// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.2) (utils/Base64.sol)

pragma solidity ^0.8.20;

/**
 * @dev Provides a set of functions to operate with Base64 strings.
 */
library Base64 {
    /**
     * @dev Base64 Encoding/Decoding Table
     */
    string internal constant _TABLE = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

    /**
     * @dev Converts a `bytes` to its Bytes64 `string` representation.
     */
    function encode(bytes memory data) internal pure returns (string memory) {
        /**
         * Inspired by Brecht Devos (Brechtpd) implementation - MIT licence
         * https://github.com/Brechtpd/base64/blob/e78d9fd951e7b0977ddca77d92dc85183770daf4/base64.sol
         */
        if (data.length == 0) return "";

        // Loads the table into memory
        string memory table = _TABLE;

        // Encoding takes 3 bytes chunks of binary data from `bytes` data parameter
        // and split into 4 numbers of 6 bits.
        // The final Base64 length should be `bytes` data length multiplied by 4/3 rounded up
        // - `data.length + 2`  -> Round up
        // - `/ 3`              -> Number of 3-bytes chunks
        // - `4 *`              -> 4 characters for each chunk
        string memory result = new string(4 * ((data.length + 2) / 3));

        /// @solidity memory-safe-assembly
        assembly {
            // Prepare the lookup table (skip the first "length" byte)
            let tablePtr := add(table, 1)

            // Prepare result pointer, jump over length
            let resultPtr := add(result, 0x20)
            let dataPtr := data
            let endPtr := add(data, mload(data))

            // In some cases, the last iteration will read bytes after the end of the data. We cache the value, and
            // set it to zero to make sure no dirty bytes are read in that section.
            let afterPtr := add(endPtr, 0x20)
            let afterCache := mload(afterPtr)
            mstore(afterPtr, 0x00)

            // Run over the input, 3 bytes at a time
            for {

            } lt(dataPtr, endPtr) {

            } {
                // Advance 3 bytes
                dataPtr := add(dataPtr, 3)
                let input := mload(dataPtr)

                // To write each character, shift the 3 byte (24 bits) chunk
                // 4 times in blocks of 6 bits for each character (18, 12, 6, 0)
                // and apply logical AND with 0x3F to bitmask the least significant 6 bits.
                // Use this as an index into the lookup table, mload an entire word
                // so the desired character is in the least significant byte, and
                // mstore8 this least significant byte into the result and continue.

                mstore8(resultPtr, mload(add(tablePtr, and(shr(18, input), 0x3F))))
                resultPtr := add(resultPtr, 1) // Advance

                mstore8(resultPtr, mload(add(tablePtr, and(shr(12, input), 0x3F))))
                resultPtr := add(resultPtr, 1) // Advance

                mstore8(resultPtr, mload(add(tablePtr, and(shr(6, input), 0x3F))))
                resultPtr := add(resultPtr, 1) // Advance

                mstore8(resultPtr, mload(add(tablePtr, and(input, 0x3F))))
                resultPtr := add(resultPtr, 1) // Advance
            }

            // Reset the value that was cached
            mstore(afterPtr, afterCache)

            // When data `bytes` is not exactly 3 bytes long
            // it is padded with `=` characters at the end
            switch mod(mload(data), 3)
            case 1 {
                mstore8(sub(resultPtr, 1), 0x3d)
                mstore8(sub(resultPtr, 2), 0x3d)
            }
            case 2 {
                mstore8(sub(resultPtr, 1), 0x3d)
            }
        }

        return result;
    }
}

// SPDX-License-Identifier: Apache-2.0

pragma solidity ^0.8.21;

import {
    RMRKAbstractEquippable
} from "@rmrk-team/evm-contracts/contracts/implementations/abstract/RMRKAbstractEquippable.sol";
import {
    RMRKImplementationBase
} from "@rmrk-team/evm-contracts/contracts/implementations/utils/RMRKImplementationBase.sol";
import {
    RMRKTokenHolder
} from "@rmrk-team/evm-contracts/contracts/RMRK/extension/tokenHolder/RMRKTokenHolder.sol";
import {IERC165} from "@openzeppelin/contracts/utils/introspection/IERC165.sol";
import {Base64} from "@openzeppelin/contracts/utils/Base64.sol";
import {Strings} from "@openzeppelin/contracts/utils/Strings.sol";
import {IChunkies} from "./IChunkies.sol";

error OnlyNFTOwnerCanTransferTokensFromIt();
error LengthMismatch();

contract Chunkies is
    RMRKAbstractEquippable,
    RMRKTokenHolder /** , IChunkies */
{
    using Strings for uint256;

    // Events
    /**
     * @notice From ERC4906 This event emits when the metadata of a token is changed.
     *  So that the third-party platforms such as NFT market could
     *  get notified when the metadata of a token is changed.
     */
    event MetadataUpdate(uint256 _tokenId);

    // Variables
    mapping(address => bool) private _autoAcceptCollection;

    mapping(uint64 assetId => bool isOthala) private _othalaAssets;
    mapping(uint64 assetId => bool isDead) private _deadAssets;

    string private _baseAnimationURI;
    string private _baseImageURI;
    string private _othalaDescription;
    string private _regularDescription;
    string private _addressAsString;
    mapping(uint256 tokenId => uint256 timestamp) private _lastEquipUpdate;
    uint256 private immutable _deployedTimestamp = block.timestamp;

    // Constructor
    constructor(
        string memory collectionMetadata,
        address royaltyRecipient,
        uint16 royaltyPercentageBps,
        string memory othalaDescription,
        string memory regularDescription
    )
        RMRKImplementationBase(
            "Chunkies",
            "CHNK",
            collectionMetadata,
            2 ** 256 - 1, // Infinite supply
            royaltyRecipient,
            royaltyPercentageBps
        )
    {
        _othalaDescription = othalaDescription;
        _regularDescription = regularDescription;
    }

    function mintWithAsset(
        address to,
        uint256 numToMint,
        uint64 assetId
    ) external onlyOwnerOrContributor returns (uint256 firstTokenId) {
        (uint256 nextToken, uint256 totalSupplyOffset) = _prepareMint(
            numToMint
        );
        for (uint256 tokenId = nextToken; tokenId < totalSupplyOffset; ) {
            _safeMint(to, tokenId, "");
            _addAssetToToken(tokenId, assetId, 0);
            _acceptAsset(tokenId, 0, assetId);
            unchecked {
                ++tokenId;
            }
        }
        firstTokenId = nextToken;
    }

    // ------------------ TOKEN URI ------------------

    function setBaseAnimationURI(
        string memory baseAnimationURI
    ) external onlyOwnerOrContributor {
        _baseAnimationURI = baseAnimationURI;
    }

    function setBaseImageURI(
        string memory baseImageURI
    ) external onlyOwnerOrContributor {
        _baseImageURI = baseImageURI;
    }

    function tokenURI(uint256 tokenId) external view returns (string memory) {
        _requireMinted(tokenId);
        string memory tokenID = tokenId.toString();
        uint64 mainAssetId = getActiveAssets(tokenId)[0];
        (bool isOthala_, ) = getAssetConfiguration(mainAssetId);
        string memory json = string(
            abi.encodePacked(
                '{\n\t"name": "',
                _deadAssets[mainAssetId] ? "Dead " : "",
                isOthala_ ? "Othala " : "",
                "Chunky #",
                tokenID,
                '",\n\t"description": "',
                isOthala_ ? _othalaDescription : _regularDescription,
                '",\n\t"external_url": "https://skybreach.app/',
                '",\n\t"image":',
                _buildImageURI(tokenId),
                ',\n\t"animation_url": "',
                _baseAnimationURI,
                tokenID,
                '"\n}'
            )
        ); // format the json

        return
            string(
                abi.encodePacked(
                    "data:application/json;base64,",
                    Base64.encode(bytes(json))
                )
            ); // return the full concatenated string
    }

    // ------------------ ASSETS ------------------

    function getAssetConfiguration(
        uint64 assetId
    ) public view returns (bool isOthala, bool isDead) {
        isOthala = _othalaAssets[assetId];
        isDead = _deadAssets[assetId];
    }

    function configureAsset(
        uint64 assetId,
        bool isOthala_,
        bool isDead_
    ) external onlyOwnerOrContributor {
        _othalaAssets[assetId] = isOthala_;
        _deadAssets[assetId] = isDead_;
    }

    function replaceMainAsset(
        uint256 tokenId,
        uint64 newAssetId
    ) external onlyOwnerOrContributor {
        uint64 currentAssetId = _getMainAsset(tokenId);
        _addAssetToToken(tokenId, newAssetId, currentAssetId);
        _acceptAsset(tokenId, _pendingAssets[tokenId].length - 1, newAssetId);
        emit MetadataUpdate(tokenId);
    }

    function _getMainAsset(uint256 tokenId) internal view returns (uint64) {
        return getActiveAssets(tokenId)[0];
    }

    // ------------------ ERC20 ------------------

    function transferHeldERC20FromToken(
        address erc20Contract,
        uint256 tokenHolderId,
        address to,
        uint256 amount,
        bytes memory data
    ) external {
        if (_msgSender() != ownerOf(tokenHolderId)) {
            revert OnlyNFTOwnerCanTransferTokensFromIt();
        }
        _transferHeldERC20FromToken(
            erc20Contract,
            tokenHolderId,
            to,
            amount,
            data
        );
    }

    // ------------------ MISC ------------------

    /**
     * @inheritdoc IERC165
     */
    function supportsInterface(
        bytes4 interfaceId
    )
        public
        view
        override(RMRKTokenHolder, RMRKAbstractEquippable)
        returns (bool)
    {
        return
            RMRKAbstractEquippable.supportsInterface(interfaceId) ||
            RMRKTokenHolder.supportsInterface(interfaceId);
    }

    function setAutoAcceptCollection(
        address collection,
        bool autoAccept
    ) external onlyOwnerOrContributor {
        _autoAcceptCollection[collection] = autoAccept;
    }

    function addSlotPartToAsset(
        uint64 assetId,
        uint64 slotPartId
    ) external onlyOwnerOrContributor {
        _partIds[assetId].push(slotPartId);
    }

    // ------------------ INTERNAL HELPERS ------------------

    function _buildImageURI(
        uint256 tokenId
    ) internal view returns (string memory) {
        string memory tokenIdStr = tokenId.toString();
        uint256 lastEquippedInt = _lastEquipUpdate[tokenId];
        uint256 mainAssetId = _getMainAsset(tokenId);
        string memory assetIdStr = mainAssetId.toString();

        return
            string(
                abi.encodePacked(
                    '"',
                    _baseImageURI,
                    (
                        lastEquippedInt == 0
                            ? _deployedTimestamp
                            : lastEquippedInt
                    ).toString(),
                    "/",
                    Strings.toHexString(uint256(uint160(address(this))), 20),
                    "/",
                    tokenIdStr,
                    "/",
                    assetIdStr,
                    '.webp"'
                )
            );
    }

    function _beforeEquip(IntakeEquip memory data) internal override {
        _storeLastEquipUpdate(data.tokenId);
        // emit MetadataUpdate(data.tokenId);
    }

    function _beforeUnequip(uint256 tokenId, uint64, uint64) internal override {
        _storeLastEquipUpdate(tokenId);
        // emit MetadataUpdate(tokenId);
    }

    function _storeLastEquipUpdate(uint256 tokenId) private {
        _lastEquipUpdate[tokenId] = block.timestamp;
    }

    function _afterAddChild(
        uint256 tokenId,
        address childAddress,
        uint256 childId,
        bytes memory
    ) internal override {
        // Auto accept children if they are from known collections
        if (_autoAcceptCollection[childAddress]) {
            _acceptChild(
                tokenId,
                _pendingChildren[tokenId].length - 1,
                childAddress,
                childId
            );
        }
    }

    function _afterAddAssetToToken(
        uint256 tokenId,
        uint64 assetId,
        uint64 replacesAssetWithId
    ) internal override {
        // Remove auto accept from AbstractEquippable. We handle it here.
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.1) (utils/Context.sol)

pragma solidity ^0.8.20;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }

    function _contextSuffixLength() internal view virtual returns (uint256) {
        return 0;
    }
}

// SPDX-License-Identifier: Apache-2.0

pragma solidity ^0.8.21;

import {
    IERC5773
} from "@rmrk-team/evm-contracts/contracts/RMRK/multiasset/IERC5773.sol";
import {
    IERC7401
} from "@rmrk-team/evm-contracts/contracts/RMRK/nestable/IERC7401.sol";
import {
    IERC6220
} from "@rmrk-team/evm-contracts/contracts/RMRK/equippable/IERC6220.sol";

interface IChunkies is IERC5773, IERC7401, IERC6220 {
    function mintWithAsset(
        address to,
        uint256 numToMint,
        uint64 assetId
    ) external returns (uint256);

    function replaceMainAsset(uint256 tokenId, uint64 newAssetId) external;

    function getAssetConfiguration(
        uint64 assetId
    ) external view returns (bool isOthala_, bool isDead_);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/introspection/IERC165.sol)

pragma solidity ^0.8.20;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.20;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the value of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the value of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves a `value` amount of tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 value) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets a `value` amount of tokens as the allowance of `spender` over the
     * caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 value) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the
     * allowance mechanism. `value` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 value) external returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (interfaces/IERC2981.sol)

pragma solidity ^0.8.20;

import {IERC165} from "../utils/introspection/IERC165.sol";

/**
 * @dev Interface for the NFT Royalty Standard.
 *
 * A standardized way to retrieve royalty payment information for non-fungible tokens (NFTs) to enable universal
 * support for royalty payments across all NFT marketplaces and ecosystem participants.
 */
interface IERC2981 is IERC165 {
    /**
     * @dev Returns how much royalty is owed and to whom, based on a sale price that may be denominated in any unit of
     * exchange. The royalty amount is denominated and should be paid in that same unit of exchange.
     */
    function royaltyInfo(
        uint256 tokenId,
        uint256 salePrice
    ) external view returns (address receiver, uint256 royaltyAmount);
}

// SPDX-License-Identifier: Apache-2.0

pragma solidity ^0.8.21;

import {IERC165} from "@openzeppelin/contracts/utils/introspection/IERC165.sol";

/**
 * @title IERC5773
 * @author RMRK team
 * @notice Interface smart contract of the RMRK multi asset module.
 */
interface IERC5773 is IERC165 {
    /**
     * @notice Used to notify listeners that an asset object is initialized at `assetId`.
     * @param assetId ID of the asset that was initialized
     */
    event AssetSet(uint64 indexed assetId);

    /**
     * @notice Used to notify listeners that an asset object at `assetId` is added to token's pending asset
     *  array.
     * @param tokenIds An array of token IDs that received a new pending asset
     * @param assetId ID of the asset that has been added to the token's pending assets array
     * @param replacesId ID of the asset that would be replaced
     */
    event AssetAddedToTokens(
        uint256[] tokenIds,
        uint64 indexed assetId,
        uint64 indexed replacesId
    );

    /**
     * @notice Used to notify listeners that an asset object at `assetId` is accepted by the token and migrated
     *  from token's pending assets array to active assets array of the token.
     * @param tokenId ID of the token that had a new asset accepted
     * @param assetId ID of the asset that was accepted
     * @param replacesId ID of the asset that was replaced
     */
    event AssetAccepted(
        uint256 indexed tokenId,
        uint64 indexed assetId,
        uint64 indexed replacesId
    );

    /**
     * @notice Used to notify listeners that an asset object at `assetId` is rejected from token and is dropped
     *  from the pending assets array of the token.
     * @param tokenId ID of the token that had an asset rejected
     * @param assetId ID of the asset that was rejected
     */
    event AssetRejected(uint256 indexed tokenId, uint64 indexed assetId);

    /**
     * @notice Used to notify listeners that token's prioritiy array is reordered.
     * @param tokenId ID of the token that had the asset priority array updated
     */
    event AssetPrioritySet(uint256 indexed tokenId);

    /**
     * @notice Used to notify listeners that owner has granted an approval to the user to manage the assets of a
     *  given token.
     * @dev Approvals must be cleared on transfer
     * @param owner Address of the account that has granted the approval for all token's assets
     * @param approved Address of the account that has been granted approval to manage the token's assets
     * @param tokenId ID of the token on which the approval was granted
     */
    event ApprovalForAssets(
        address indexed owner,
        address indexed approved,
        uint256 indexed tokenId
    );

    /**
     * @notice Used to notify listeners that owner has granted approval to the user to manage assets of all of their
     *  tokens.
     * @param owner Address of the account that has granted the approval for all assets on all of their tokens
     * @param operator Address of the account that has been granted the approval to manage the token's assets on all of
     *  the tokens
     * @param approved Boolean value signifying whether the permission has been granted (`true`) or revoked (`false`)
     */
    event ApprovalForAllForAssets(
        address indexed owner,
        address indexed operator,
        bool approved
    );

    /**
     * @notice Accepts an asset at from the pending array of given token.
     * @dev Migrates the asset from the token's pending asset array to the token's active asset array.
     * @dev Active assets cannot be removed by anyone, but can be replaced by a new asset.
     * @dev Requirements:
     *
     *  - The caller must own the token or be approved to manage the token's assets
     *  - `tokenId` must exist.
     *  - `index` must be in range of the length of the pending asset array.
     * @dev Emits an {AssetAccepted} event.
     * @param tokenId ID of the token for which to accept the pending asset
     * @param index Index of the asset in the pending array to accept
     * @param assetId ID of the asset expected to be in the index
     */
    function acceptAsset(
        uint256 tokenId,
        uint256 index,
        uint64 assetId
    ) external;

    /**
     * @notice Rejects an asset from the pending array of given token.
     * @dev Removes the asset from the token's pending asset array.
     * @dev Requirements:
     *
     *  - The caller must own the token or be approved to manage the token's assets
     *  - `tokenId` must exist.
     *  - `index` must be in range of the length of the pending asset array.
     * @dev Emits a {AssetRejected} event.
     * @param tokenId ID of the token that the asset is being rejected from
     * @param index Index of the asset in the pending array to be rejected
     * @param assetId ID of the asset expected to be in the index
     */
    function rejectAsset(
        uint256 tokenId,
        uint256 index,
        uint64 assetId
    ) external;

    /**
     * @notice Rejects all assets from the pending array of a given token.
     * @dev Effecitvely deletes the pending array.
     * @dev Requirements:
     *
     *  - The caller must own the token or be approved to manage the token's assets
     *  - `tokenId` must exist.
     * @dev Emits a {AssetRejected} event with assetId = 0.
     * @param tokenId ID of the token of which to clear the pending array.
     * @param maxRejections Maximum number of expected assets to reject, used to prevent from rejecting assets which
     *  arrive just before this operation.
     */
    function rejectAllAssets(uint256 tokenId, uint256 maxRejections) external;

    /**
     * @notice Sets a new priority array for a given token.
     * @dev The priority array is a non-sequential list of `uint64`s, where the lowest value is considered highest
     *  priority.
     * @dev Value `0` of a priority is a special case equivalent to unitialized.
     * @dev Requirements:
     *
     *  - The caller must own the token or be approved to manage the token's assets
     *  - `tokenId` must exist.
     *  - The length of `priorities` must be equal the length of the active assets array.
     * @dev Emits a {AssetPrioritySet} event.
     * @param tokenId ID of the token to set the priorities for
     * @param priorities An array of priorities of active assets. The succesion of items in the priorities array
     *  matches that of the succesion of items in the active array
     */
    function setPriority(
        uint256 tokenId,
        uint64[] calldata priorities
    ) external;

    /**
     * @notice Used to retrieve IDs of the active assets of given token.
     * @dev Asset data is stored by reference, in order to access the data corresponding to the ID, call
     *  `getAssetMetadata(tokenId, assetId)`.
     * @dev You can safely get 10k
     * @param tokenId ID of the token to retrieve the IDs of the active assets
     * @return assetIds An array of active asset IDs of the given token
     */
    function getActiveAssets(
        uint256 tokenId
    ) external view returns (uint64[] memory assetIds);

    /**
     * @notice Used to retrieve IDs of the pending assets of given token.
     * @dev Asset data is stored by reference, in order to access the data corresponding to the ID, call
     *  `getAssetMetadata(tokenId, assetId)`.
     * @param tokenId ID of the token to retrieve the IDs of the pending assets
     * @return assetIds An array of pending asset IDs of the given token
     */
    function getPendingAssets(
        uint256 tokenId
    ) external view returns (uint64[] memory assetIds);

    /**
     * @notice Used to retrieve the priorities of the active resoources of a given token.
     * @dev Asset priorities are a non-sequential array of uint64 values with an array size equal to active asset
     *  priorites.
     * @param tokenId ID of the token for which to retrieve the priorities of the active assets
     * @return priorities An array of priorities of the active assets of the given token
     */
    function getActiveAssetPriorities(
        uint256 tokenId
    ) external view returns (uint64[] memory priorities);

    /**
     * @notice Used to retrieve the asset that will be replaced if a given asset from the token's pending array
     *  is accepted.
     * @dev Asset data is stored by reference, in order to access the data corresponding to the ID, call
     *  `getAssetMetadata(tokenId, assetId)`.
     * @param tokenId ID of the token to check
     * @param newAssetId ID of the pending asset which will be accepted
     * @return replacesAssetWithId ID of the asset which will be replaced
     */
    function getAssetReplacements(
        uint256 tokenId,
        uint64 newAssetId
    ) external view returns (uint64 replacesAssetWithId);

    /**
     * @notice Used to fetch the asset metadata of the specified token's active asset with the given index.
     * @dev Assets are stored by reference mapping `_assets[assetId]`.
     * @dev Can be overriden to implement enumerate, fallback or other custom logic.
     * @param tokenId ID of the token from which to retrieve the asset metadata
     * @param assetId Asset Id, must be in the active assets array
     * @return metadata The metadata of the asset belonging to the specified index in the token's active assets
     *  array
     */
    function getAssetMetadata(
        uint256 tokenId,
        uint64 assetId
    ) external view returns (string memory metadata);

    // Approvals

    /**
     * @notice Used to grant permission to the user to manage token's assets.
     * @dev This differs from transfer approvals, as approvals are not cleared when the approved party accepts or
     *  rejects an asset, or sets asset priorities. This approval is cleared on token transfer.
     * @dev Only a single account can be approved at a time, so approving the `0x0` address clears previous approvals.
     * @dev Requirements:
     *
     *  - The caller must own the token or be an approved operator.
     *  - `tokenId` must exist.
     * @dev Emits an {ApprovalForAssets} event.
     * @param to Address of the account to grant the approval to
     * @param tokenId ID of the token for which the approval to manage the assets is granted
     */
    function approveForAssets(address to, uint256 tokenId) external;

    /**
     * @notice Used to retrieve the address of the account approved to manage assets of a given token.
     * @dev Requirements:
     *
     *  - `tokenId` must exist.
     * @param tokenId ID of the token for which to retrieve the approved address
     * @return approved Address of the account that is approved to manage the specified token's assets
     */
    function getApprovedForAssets(
        uint256 tokenId
    ) external view returns (address approved);

    /**
     * @notice Used to add or remove an operator of assets for the caller.
     * @dev Operators can call {acceptAsset}, {rejectAsset}, {rejectAllAssets} or {setPriority} for any token
     *  owned by the caller.
     * @dev Requirements:
     *
     *  - The `operator` cannot be the caller.
     * @dev Emits an {ApprovalForAllForAssets} event.
     * @param operator Address of the account to which the operator role is granted or revoked from
     * @param approved The boolean value indicating whether the operator role is being granted (`true`) or revoked
     *  (`false`)
     */
    function setApprovalForAllForAssets(
        address operator,
        bool approved
    ) external;

    /**
     * @notice Used to check whether the address has been granted the operator role by a given address or not.
     * @dev See {setApprovalForAllForAssets}.
     * @param owner Address of the account that we are checking for whether it has granted the operator role
     * @param operator Address of the account that we are checking whether it has the operator role or not
     * @return isApproved A boolean value indicating whether the account we are checking has been granted the operator role
     */
    function isApprovedForAllForAssets(
        address owner,
        address operator
    ) external view returns (bool isApproved);
}

// SPDX-License-Identifier: Apache-2.0

pragma solidity ^0.8.21;

import {IERC5773} from "../multiasset/IERC5773.sol";

/**
 * @title IERC6220
 * @author RMRK team
 * @notice Interface smart contract of the RMRK equippable module.
 */
interface IERC6220 is IERC5773 {
    /**
     * @notice Used to store the core structure of the `Equippable` RMRK lego.
     * @return assetId The ID of the asset equipping a child
     * @return childAssetId The ID of the asset used as equipment
     * @return childId The ID of token that is equipped
     * @return childEquippableAddress Address of the collection to which the child asset belongs to
     */
    struct Equipment {
        uint64 assetId;
        uint64 childAssetId;
        uint256 childId;
        address childEquippableAddress;
    }

    /**
     * @notice Used to provide a struct for inputing equip data.
     * @dev Only used for input and not storage of data.
     * @return tokenId ID of the token we are managing
     * @return childIndex Index of a child in the list of token's active children
     * @return assetId ID of the asset that we are equipping into
     * @return slotPartId ID of the slot part that we are using to equip
     * @return childAssetId ID of the asset that we are equipping
     */
    struct IntakeEquip {
        uint256 tokenId;
        uint256 childIndex;
        uint64 assetId;
        uint64 slotPartId;
        uint64 childAssetId;
    }

    /**
     * @notice Used to notify listeners that a child's asset has been equipped into one of its parent assets.
     * @param tokenId ID of the token that had an asset equipped
     * @param assetId ID of the asset associated with the token we are equipping into
     * @param slotPartId ID of the slot we are using to equip
     * @param childId ID of the child token we are equipping into the slot
     * @param childAddress Address of the child token's collection
     * @param childAssetId ID of the asset associated with the token we are equipping
     */
    event ChildAssetEquipped(
        uint256 indexed tokenId,
        uint64 indexed assetId,
        uint64 indexed slotPartId,
        uint256 childId,
        address childAddress,
        uint64 childAssetId
    );

    /**
     * @notice Used to notify listeners that a child's asset has been unequipped from one of its parent assets.
     * @param tokenId ID of the token that had an asset unequipped
     * @param assetId ID of the asset associated with the token we are unequipping out of
     * @param slotPartId ID of the slot we are unequipping from
     * @param childId ID of the token being unequipped
     * @param childAddress Address of the collection that a token that is being unequipped belongs to
     * @param childAssetId ID of the asset associated with the token we are unequipping
     */
    event ChildAssetUnequipped(
        uint256 indexed tokenId,
        uint64 indexed assetId,
        uint64 indexed slotPartId,
        uint256 childId,
        address childAddress,
        uint64 childAssetId
    );

    /**
     * @notice Used to notify listeners that the assets belonging to a `equippableGroupId` have been marked as
     *  equippable into a given slot and parent
     * @param equippableGroupId ID of the equippable group being marked as equippable into the slot associated with
     *  `slotPartId` of the `parentAddress` collection
     * @param slotPartId ID of the slot part of the catalog into which the parts belonging to the equippable group
     *  associated with `equippableGroupId` can be equipped
     * @param parentAddress Address of the collection into which the parts belonging to `equippableGroupId` can be
     *  equipped
     */
    event ValidParentEquippableGroupIdSet(
        uint64 indexed equippableGroupId,
        uint64 indexed slotPartId,
        address parentAddress
    );

    /**
     * @notice Used to equip a child into a token.
     * @dev The `IntakeEquip` stuct contains the following data:
     *  [
     *      tokenId,
     *      childIndex,
     *      assetId,
     *      slotPartId,
     *      childAssetId
     *  ]
     * @param data An `IntakeEquip` struct specifying the equip data
     */
    function equip(IntakeEquip memory data) external;

    /**
     * @notice Used to unequip child from parent token.
     * @dev This can only be called by the owner of the token or by an account that has been granted permission to
     *  manage the given token by the current owner.
     * @param tokenId ID of the parent from which the child is being unequipped
     * @param assetId ID of the parent's asset that contains the `Slot` into which the child is equipped
     * @param slotPartId ID of the `Slot` from which to unequip the child
     */
    function unequip(
        uint256 tokenId,
        uint64 assetId,
        uint64 slotPartId
    ) external;

    /**
     * @notice Used to check whether the token has a given child equipped.
     * @dev This is used to prevent from transferring a child that is equipped.
     * @param tokenId ID of the parent token for which we are querying for
     * @param childAddress Address of the child token's smart contract
     * @param childId ID of the child token
     * @return isEquipped A boolean value indicating whether the child token is equipped into the given token or not
     */
    function isChildEquipped(
        uint256 tokenId,
        address childAddress,
        uint256 childId
    ) external view returns (bool isEquipped);

    /**
     * @notice Used to verify whether a token can be equipped into a given parent's slot.
     * @param parent Address of the parent token's smart contract
     * @param tokenId ID of the token we want to equip
     * @param assetId ID of the asset associated with the token we want to equip
     * @param slotId ID of the slot that we want to equip the token into
     * @return canBeEquipped A boolean indicating whether the token with the given asset can be equipped into the desired slot
     */
    function canTokenBeEquippedWithAssetIntoSlot(
        address parent,
        uint256 tokenId,
        uint64 assetId,
        uint64 slotId
    ) external view returns (bool canBeEquipped);

    /**
     * @notice Used to get the Equipment object equipped into the specified slot of the desired token.
     * @dev The `Equipment` struct consists of the following data:
     *  [
     *      assetId,
     *      childAssetId,
     *      childId,
     *      childEquippableAddress
     *  ]
     * @param tokenId ID of the token for which we are retrieving the equipped object
     * @param targetCatalogAddress Address of the `Catalog` associated with the `Slot` part of the token
     * @param slotPartId ID of the `Slot` part that we are checking for equipped objects
     * @return equipment The `Equipment` struct containing data about the equipped object
     */
    function getEquipment(
        uint256 tokenId,
        address targetCatalogAddress,
        uint64 slotPartId
    ) external view returns (Equipment memory equipment);

    /**
     * @notice Used to get the asset and equippable data associated with given `assetId`.
     * @param tokenId ID of the token for which to retrieve the asset
     * @param assetId ID of the asset of which we are retrieving
     * @return metadataURI The metadata URI of the asset
     * @return equippableGroupId ID of the equippable group this asset belongs to
     * @return catalogAddress The address of the catalog the part belongs to
     * @return partIds An array of IDs of parts included in the asset
     */
    function getAssetAndEquippableData(
        uint256 tokenId,
        uint64 assetId
    )
        external
        view
        returns (
            string memory metadataURI,
            uint64 equippableGroupId,
            address catalogAddress,
            uint64[] memory partIds
        );
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.20;

import {IERC165} from "../../utils/introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon
     *   a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) external;

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must have been allowed to move this token by either {approve} or
     *   {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon
     *   a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Note that the caller is responsible to confirm that the recipient is capable of receiving ERC721
     * or else they may be permanently lost. Usage of {safeTransferFrom} prevents loss, though the caller must
     * understand this adds an external call which potentially creates a reentrancy vulnerability.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 tokenId) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the address zero.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool approved) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC721/extensions/IERC721Metadata.sol)

pragma solidity ^0.8.20;

import {IERC721} from "../IERC721.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Metadata is IERC721 {
    /**
     * @dev Returns the token collection name.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the token collection symbol.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
     */
    function tokenURI(uint256 tokenId) external view returns (string memory);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.20;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be
     * reverted.
     *
     * The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

// SPDX-License-Identifier: Apache-2.0

pragma solidity ^0.8.21;

import {IERC165} from "@openzeppelin/contracts/utils/introspection/IERC165.sol";

/**
 * @title IERC7401
 * @author RMRK team
 * @notice Interface smart contract of the RMRK nestable module.
 */
interface IERC7401 is IERC165 {
    /**
     * @notice The core struct of RMRK ownership.
     * @dev The `DirectOwner` struct is used to store information of the next immediate owner, be it the parent token or
     *  the externally owned account.
     * @dev If the token is owned by the externally owned account, the `tokenId` should equal `0`.
     * @param tokenId ID of the parent token
     * @param ownerAddress Address of the owner of the token. If the owner is another token, then the address should be
     *  the one of the parent token's collection smart contract. If the owner is externally owned account, the address
     *  should be the address of this account
     * @param isNft A boolean value signifying whether the token is owned by another token (`true`) or by an externally
     *  owned account (`false`)
     */
    struct DirectOwner {
        uint256 tokenId;
        address ownerAddress;
    }

    /**
     * @notice Used to notify listeners that the token is being transferred.
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     * @param from Address of the previous immediate owner, which is a smart contract if the token was nested.
     * @param to Address of the new immediate owner, which is a smart contract if the token is being nested.
     * @param fromTokenId ID of the previous parent token. If the token was not nested before, the value should be `0`
     * @param toTokenId ID of the new parent token. If the token is not being nested, the value should be `0`
     * @param tokenId ID of the token being transferred
     */
    event NestTransfer(
        address indexed from,
        address indexed to,
        uint256 fromTokenId,
        uint256 toTokenId,
        uint256 indexed tokenId
    );

    /**
     * @notice Used to notify listeners that a new token has been added to a given token's pending children array.
     * @dev Emitted when a child NFT is added to a token's pending array.
     * @param tokenId ID of the token that received a new pending child token
     * @param childIndex Index of the proposed child token in the parent token's pending children array
     * @param childAddress Address of the proposed child token's collection smart contract
     * @param childId ID of the child token in the child token's collection smart contract
     */
    event ChildProposed(
        uint256 indexed tokenId,
        uint256 childIndex,
        address indexed childAddress,
        uint256 indexed childId
    );

    /**
     * @notice Used to notify listeners that a new child token was accepted by the parent token.
     * @dev Emitted when a parent token accepts a token from its pending array, migrating it to the active array.
     * @param tokenId ID of the token that accepted a new child token
     * @param childIndex Index of the newly accepted child token in the parent token's active children array
     * @param childAddress Address of the child token's collection smart contract
     * @param childId ID of the child token in the child token's collection smart contract
     */
    event ChildAccepted(
        uint256 indexed tokenId,
        uint256 childIndex,
        address indexed childAddress,
        uint256 indexed childId
    );

    /**
     * @notice Used to notify listeners that all pending child tokens of a given token have been rejected.
     * @dev Emitted when a token removes all a child tokens from its pending array.
     * @param tokenId ID of the token that rejected all of the pending children
     */
    event AllChildrenRejected(uint256 indexed tokenId);

    /**
     * @notice Used to notify listeners a child token has been transferred from parent token.
     * @dev Emitted when a token transfers a child from itself, transferring ownership to the root owner.
     * @param tokenId ID of the token that transferred a child token
     * @param childIndex Index of a child in the array from which it is being transferred
     * @param childAddress Address of the child token's collection smart contract
     * @param childId ID of the child token in the child token's collection smart contract
     * @param fromPending A boolean value signifying whether the token was in the pending child tokens array (`true`) or
     *  in the active child tokens array (`false`)
     * @param toZero A boolean value signifying whether the token is being transferred to the `0x0` address (`true`) or
     *  not (`false`)
     */
    event ChildTransferred(
        uint256 indexed tokenId,
        uint256 childIndex,
        address indexed childAddress,
        uint256 indexed childId,
        bool fromPending,
        bool toZero
    );

    /**
     * @notice The core child token struct, holding the information about the child tokens.
     * @return tokenId ID of the child token in the child token's collection smart contract
     * @return contractAddress Address of the child token's smart contract
     */
    struct Child {
        uint256 tokenId;
        address contractAddress;
    }

    /**
     * @notice Used to retrieve the *root* owner of a given token.
     * @dev The *root* owner of the token is an externally owned account (EOA). If the given token is child of another
     *  NFT, this will return an EOA address. Otherwise, if the token is owned by an EOA, this EOA will be returned.
     * @param tokenId ID of the token for which the *root* owner has been retrieved
     * @return owner_ The *root* owner of the token
     */
    function ownerOf(uint256 tokenId) external view returns (address owner_);

    /**
     * @notice Used to retrieve the immediate owner of the given token.
     * @dev If the immediate owner is another token, the address returned will be the parent token's collection address.
     * @param tokenId ID of the token for which the RMRK owner is being retrieved
     * @return owner Address of the given token's owner
     * @return parentId The ID of the parent token. Should be `0` if the owner is an externally owned account
     * @return isNFT The boolean value signifying whether the owner is an NFT or not
     */
    function directOwnerOf(
        uint256 tokenId
    ) external view returns (address owner, uint256 parentId, bool isNFT);

    /**
     * @notice Used to burn a given token.
     * @dev When a token is burned, all of its child tokens are recursively burned as well.
     * @dev When specifying the maximum recursive burns, the execution will be reverted if there are more children to be
     *  burned.
     * @dev Setting the `maxRecursiveBurn` value to 0 will only attempt to burn the specified token and revert if there
     *  are any child tokens present.
     * @dev The approvals are cleared when the token is burned.
     * @dev Requirements:
     *
     *  - `tokenId` must exist.
     * @dev Emits a {Transfer} event.
     * @param tokenId ID of the token to burn
     * @param maxRecursiveBurns Maximum number of tokens to recursively burn
     * @return burnedChildren Number of recursively burned children
     */
    function burn(
        uint256 tokenId,
        uint256 maxRecursiveBurns
    ) external returns (uint256 burnedChildren);

    /**
     * @notice Used to add a child token to a given parent token.
     * @dev This adds the child token into the given parent token's pending child tokens array.
     * @dev Requirements:
     *
     *  - `directOwnerOf` on the child contract must resolve to the called contract.
     *  - the pending array of the parent contract must not be full.
     * @param parentId ID of the parent token to receive the new child token
     * @param childId ID of the new proposed child token
     * @param data Additional data with no specified format
     */
    function addChild(
        uint256 parentId,
        uint256 childId,
        bytes memory data
    ) external;

    /**
     * @notice Used to accept a pending child token for a given parent token.
     * @dev This moves the child token from parent token's pending child tokens array into the active child tokens
     *  array.
     * @param parentId ID of the parent token for which the child token is being accepted
     * @param childIndex Index of a child tokem in the given parent's pending children array
     * @param childAddress Address of the collection smart contract of the child token expected to be located at the
     *  specified index of the given parent token's pending children array
     * @param childId ID of the child token expected to be located at the specified index of the given parent token's
     *  pending children array
     */
    function acceptChild(
        uint256 parentId,
        uint256 childIndex,
        address childAddress,
        uint256 childId
    ) external;

    /**
     * @notice Used to reject all pending children of a given parent token.
     * @dev Removes the children from the pending array mapping.
     * @dev This does not update the ownership storage data on children. If necessary, ownership can be reclaimed by the
     *  rootOwner of the previous parent.
     * @dev Requirements:
     *
     * Requirements:
     *
     * - `parentId` must exist
     * @param parentId ID of the parent token for which to reject all of the pending tokens.
     * @param maxRejections Maximum number of expected children to reject, used to prevent from rejecting children which
     *  arrive just before this operation.
     */
    function rejectAllChildren(
        uint256 parentId,
        uint256 maxRejections
    ) external;

    /**
     * @notice Used to transfer a child token from a given parent token.
     * @dev When transferring a child token, the owner of the token is set to `to`, or is not updated in the event of
     *  `to` being the `0x0` address.
     * @param tokenId ID of the parent token from which the child token is being transferred
     * @param to Address to which to transfer the token to
     * @param destinationId ID of the token to receive this child token (MUST be 0 if the destination is not a token)
     * @param childIndex Index of a token we are transferring, in the array it belongs to (can be either active array or
     *  pending array)
     * @param childAddress Address of the child token's collection smart contract.
     * @param childId ID of the child token in its own collection smart contract.
     * @param isPending A boolean value indicating whether the child token being transferred is in the pending array of
     *  the parent token (`true`) or in the active array (`false`)
     * @param data Additional data with no specified format, sent in call to `_to`
     */
    function transferChild(
        uint256 tokenId,
        address to,
        uint256 destinationId,
        uint256 childIndex,
        address childAddress,
        uint256 childId,
        bool isPending,
        bytes memory data
    ) external;

    /**
     * @notice Used to retrieve the active child tokens of a given parent token.
     * @dev Returns array of Child structs existing for parent token.
     * @dev The Child struct consists of the following values:
     *  [
     *      tokenId,
     *      contractAddress
     *  ]
     * @param parentId ID of the parent token for which to retrieve the active child tokens
     * @return children An array of Child structs containing the parent token's active child tokens
     */
    function childrenOf(
        uint256 parentId
    ) external view returns (Child[] memory children);

    /**
     * @notice Used to retrieve the pending child tokens of a given parent token.
     * @dev Returns array of pending Child structs existing for given parent.
     * @dev The Child struct consists of the following values:
     *  [
     *      tokenId,
     *      contractAddress
     *  ]
     * @param parentId ID of the parent token for which to retrieve the pending child tokens
     * @return children An array of Child structs containing the parent token's pending child tokens
     */
    function pendingChildrenOf(
        uint256 parentId
    ) external view returns (Child[] memory children);

    /**
     * @notice Used to retrieve a specific active child token for a given parent token.
     * @dev Returns a single Child struct locating at `index` of parent token's active child tokens array.
     * @dev The Child struct consists of the following values:
     *  [
     *      tokenId,
     *      contractAddress
     *  ]
     * @param parentId ID of the parent token for which the child is being retrieved
     * @param index Index of the child token in the parent token's active child tokens array
     * @return child A Child struct containing data about the specified child
     */
    function childOf(
        uint256 parentId,
        uint256 index
    ) external view returns (Child memory child);

    /**
     * @notice Used to retrieve a specific pending child token from a given parent token.
     * @dev Returns a single Child struct locating at `index` of parent token's active child tokens array.
     * @dev The Child struct consists of the following values:
     *  [
     *      tokenId,
     *      contractAddress
     *  ]
     * @param parentId ID of the parent token for which the pending child token is being retrieved
     * @param index Index of the child token in the parent token's pending child tokens array
     * @return child A Child struct containting data about the specified child
     */
    function pendingChildOf(
        uint256 parentId,
        uint256 index
    ) external view returns (Child memory child);

    /**
     * @notice Used to transfer the token into another token.
     * @param from Address of the direct owner of the token to be transferred
     * @param to Address of the receiving token's collection smart contract
     * @param tokenId ID of the token being transferred
     * @param destinationId ID of the token to receive the token being transferred
     * @param data Additional data with no specified format, sent in the addChild call
     */
    function nestTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        uint256 destinationId,
        bytes memory data
    ) external;
}

// SPDX-License-Identifier: CC0-1.0

pragma solidity ^0.8.21;

import "@openzeppelin/contracts/utils/introspection/IERC165.sol";

interface IERC7590 is IERC165 {
    /**
     * @notice Used to notify listeners that the token received ERC-20 tokens.
     * @param erc20Contract The address of the ERC-20 smart contract
     * @param toTokenId The ID of the token receiving the ERC-20 tokens
     * @param from The address of the account from which the tokens are being transferred
     * @param amount The number of ERC-20 tokens received
     */
    event ReceivedERC20(
        address indexed erc20Contract,
        uint256 indexed toTokenId,
        address indexed from,
        uint256 amount
    );

    /**
     * @notice Used to notify the listeners that the ERC-20 tokens have been transferred.
     * @param erc20Contract The address of the ERC-20 smart contract
     * @param fromTokenId The ID of the token from which the ERC-20 tokens have been transferred
     * @param to The address receiving the ERC-20 tokens
     * @param amount The number of ERC-20 tokens transferred
     */
    event TransferredERC20(
        address indexed erc20Contract,
        uint256 indexed fromTokenId,
        address indexed to,
        uint256 amount
    );

    /**
     * @notice Used to retrieve the given token's specific ERC-20 balance
     * @param erc20Contract The address of the ERC-20 smart contract
     * @param tokenId The ID of the token being checked for ERC-20 balance
     * @return The amount of the specified ERC-20 tokens owned by a given token
     */
    function balanceOfERC20(
        address erc20Contract,
        uint256 tokenId
    ) external view returns (uint256);

    /**
     * @notice Transfer ERC-20 tokens from a specific token.
     * @dev The balance MUST be transferred from this smart contract.
     * @dev MUST increase the transfer-out-nonce for the tokenId
     * @dev MUST revert if the `msg.sender` is not the owner of the NFT or approved to manage it.
     * @param erc20Contract The address of the ERC-20 smart contract
     * @param tokenId The ID of the token to transfer the ERC-20 tokens from
     * @param amount The number of ERC-20 tokens to transfer
     * @param data Additional data with no specified format, to allow for custom logic
     */
    function transferHeldERC20FromToken(
        address erc20Contract,
        uint256 tokenId,
        address to,
        uint256 amount,
        bytes memory data
    ) external;

    /**
     * @notice Transfer ERC-20 tokens to a specific token.
     * @dev The ERC-20 smart contract must have approval for this contract to transfer the ERC-20 tokens.
     * @dev The balance MUST be transferred from the `msg.sender`.
     * @param erc20Contract The address of the ERC-20 smart contract
     * @param tokenId The ID of the token to transfer ERC-20 tokens to
     * @param amount The number of ERC-20 tokens to transfer
     * @param data Additional data with no specified format, to allow for custom logic
     */
    function transferERC20ToToken(
        address erc20Contract,
        uint256 tokenId,
        uint256 amount,
        bytes memory data
    ) external;

    /**
     * @notice Nonce increased every time an ERC20 token is transferred out of a token
     * @param tokenId The ID of the token to check the nonce for
     * @return The nonce of the token
     */
    function erc20TransferOutNonce(
        uint256 tokenId
    ) external view returns (uint256);
}

// SPDX-License-Identifier: Apache-2.0

pragma solidity ^0.8.21;

import {IERC165} from "@openzeppelin/contracts/utils/introspection/IERC165.sol";

/**
 * @title IRMRKCatalog
 * @author RMRK team
 * @notice An interface Catalog for RMRK equippable module.
 */
interface IRMRKCatalog is IERC165 {
    /**
     * @notice Event to announce addition of a new part.
     * @dev It is emitted when a new part is added.
     * @param partId ID of the part that was added
     * @param itemType Enum value specifying whether the part is `None`, `Slot` and `Fixed`
     * @param zIndex An uint specifying the z value of the part. It is used to specify the depth which the part should
     *  be rendered at
     * @param equippableAddresses An array of addresses that can equip this part
     * @param metadataURI The metadata URI of the part
     */
    event AddedPart(
        uint64 indexed partId,
        ItemType indexed itemType,
        uint8 zIndex,
        address[] equippableAddresses,
        string metadataURI
    );

    /**
     * @notice Event to announce new equippables to the part.
     * @dev It is emitted when new addresses are marked as equippable for `partId`.
     * @param partId ID of the part that had new equippable addresses added
     * @param equippableAddresses An array of the new addresses that can equip this part
     */
    event AddedEquippables(
        uint64 indexed partId,
        address[] equippableAddresses
    );

    /**
     * @notice Event to announce the overriding of equippable addresses of the part.
     * @dev It is emitted when the existing list of addresses marked as equippable for `partId` is overwritten by a new one.
     * @param partId ID of the part whose list of equippable addresses was overwritten
     * @param equippableAddresses The new, full, list of addresses that can equip this part
     */
    event SetEquippables(uint64 indexed partId, address[] equippableAddresses);

    /**
     * @notice Event to announce that a given part can be equipped by any address.
     * @dev It is emitted when a given part is marked as equippable by any.
     * @param partId ID of the part marked as equippable by any address
     */
    event SetEquippableToAll(uint64 indexed partId);

    /**
     * @notice Used to define a type of the item. Possible values are `None`, `Slot` or `Fixed`.
     * @dev Used for fixed and slot parts.
     */
    enum ItemType {
        None,
        Slot,
        Fixed
    }

    /**
     * @notice The integral structure of a standard RMRK catalog item defining it.
     * @dev Requires a minimum of 3 storage slots per catalog item, equivalent to roughly 60,000 gas as of Berlin hard
     *  fork (April 14, 2021), though 5-7 storage slots is more realistic, given the standard length of an IPFS URI.
     *  This will result in between 25,000,000 and 35,000,000 gas per 250 assets--the maximum block size of Ethereum
     *  mainnet is 30M at peak usage.
     * @return itemType The item type of the part
     * @return z The z value of the part defining how it should be rendered when presenting the full NFT
     * @return equippable The array of addresses allowed to be equipped in this part
     * @return metadataURI The metadata URI of the part
     */
    struct Part {
        ItemType itemType; //1 byte
        uint8 z; //1 byte
        address[] equippable; //n Collections that can be equipped into this slot
        string metadataURI; //n bytes 32+
    }

    /**
     * @notice The structure used to add a new `Part`.
     * @dev The part is added with specified ID, so you have to make sure that you are using an unused `partId`,
     *  otherwise the addition of the part vill be reverted.
     * @dev The full `IntakeStruct` looks like this:
     *  [
     *          partID,
     *      [
     *          itemType,
     *          z,
     *          [
     *               permittedCollectionAddress0,
     *               permittedCollectionAddress1,
     *               permittedCollectionAddress2
     *           ],
     *           metadataURI
     *       ]
     *   ]
     * @return partId ID to be assigned to the `Part`
     * @return part A `Part` to be added
     */
    struct IntakeStruct {
        uint64 partId;
        Part part;
    }

    /**
     * @notice Used to return the metadata URI of the associated Catalog.
     * @return Catalog metadata URI
     */
    function getMetadataURI() external view returns (string memory);

    /**
     * @notice Used to return the `itemType` of the associated Catalog
     * @return `itemType` of the associated Catalog
     */
    function getType() external view returns (string memory);

    /**
     * @notice Used to check whether the given address is allowed to equip the desired `Part`.
     * @dev Returns true if a collection may equip asset with `partId`.
     * @param partId The ID of the part that we are checking
     * @param targetAddress The address that we are checking for whether the part can be equipped into it or not
     * @return isEquippable The status indicating whether the `targetAddress` can be equipped into `Part` with `partId` or not
     */
    function checkIsEquippable(
        uint64 partId,
        address targetAddress
    ) external view returns (bool isEquippable);

    /**
     * @notice Used to check if the part is equippable by all addresses.
     * @dev Returns true if part is equippable to all.
     * @param partId ID of the part that we are checking
     * @return isEquippableToAll The status indicating whether the part with `partId` can be equipped by any address or not
     */
    function checkIsEquippableToAll(
        uint64 partId
    ) external view returns (bool isEquippableToAll);

    /**
     * @notice Used to retrieve a `Part` with id `partId`
     * @param partId ID of the part that we are retrieving
     * @return part The `Part` struct associated with given `partId`
     */
    function getPart(uint64 partId) external view returns (Part memory part);

    /**
     * @notice Used to retrieve multiple parts at the same time.
     * @param partIds An array of part IDs that we want to retrieve
     * @return part An array of `Part` structs associated with given `partIds`
     */
    function getParts(
        uint64[] memory partIds
    ) external view returns (Part[] memory part);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/math/Math.sol)

pragma solidity ^0.8.20;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    /**
     * @dev Muldiv operation overflow.
     */
    error MathOverflowedMulDiv();

    enum Rounding {
        Floor, // Toward negative infinity
        Ceil, // Toward positive infinity
        Trunc, // Toward zero
        Expand // Away from zero
    }

    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, with an overflow flag.
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
            // benefit is lost if 'b' is also tested.
            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
            if (a == 0) return (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }

    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds towards infinity instead
     * of rounding towards zero.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        if (b == 0) {
            // Guarantee the same behavior as in a regular Solidity division.
            return a / b;
        }

        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a == 0 ? 0 : (a - 1) / b + 1;
    }

    /**
     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or
     * denominator == 0.
     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv) with further edits by
     * Uniswap Labs also under MIT license.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
        unchecked {
            // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
            // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
            // variables such that product = prod1 * 2^256 + prod0.
            uint256 prod0 = x * y; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod1 := sub(sub(mm, prod0), lt(mm, prod0))
            }

            // Handle non-overflow cases, 256 by 256 division.
            if (prod1 == 0) {
                // Solidity will revert if denominator == 0, unlike the div opcode on its own.
                // The surrounding unchecked block does not change this fact.
                // See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
                return prod0 / denominator;
            }

            // Make sure the result is less than 2^256. Also prevents denominator == 0.
            if (denominator <= prod1) {
                revert MathOverflowedMulDiv();
            }

            ///////////////////////////////////////////////
            // 512 by 256 division.
            ///////////////////////////////////////////////

            // Make division exact by subtracting the remainder from [prod1 prod0].
            uint256 remainder;
            assembly {
                // Compute remainder using mulmod.
                remainder := mulmod(x, y, denominator)

                // Subtract 256 bit number from 512 bit number.
                prod1 := sub(prod1, gt(remainder, prod0))
                prod0 := sub(prod0, remainder)
            }

            // Factor powers of two out of denominator and compute largest power of two divisor of denominator.
            // Always >= 1. See https://cs.stackexchange.com/q/138556/92363.

            uint256 twos = denominator & (0 - denominator);
            assembly {
                // Divide denominator by twos.
                denominator := div(denominator, twos)

                // Divide [prod1 prod0] by twos.
                prod0 := div(prod0, twos)

                // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                twos := add(div(sub(0, twos), twos), 1)
            }

            // Shift in bits from prod1 into prod0.
            prod0 |= prod1 * twos;

            // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
            // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
            // four bits. That is, denominator * inv = 1 mod 2^4.
            uint256 inverse = (3 * denominator) ^ 2;

            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also
            // works in modular arithmetic, doubling the correct bits in each step.
            inverse *= 2 - denominator * inverse; // inverse mod 2^8
            inverse *= 2 - denominator * inverse; // inverse mod 2^16
            inverse *= 2 - denominator * inverse; // inverse mod 2^32
            inverse *= 2 - denominator * inverse; // inverse mod 2^64
            inverse *= 2 - denominator * inverse; // inverse mod 2^128
            inverse *= 2 - denominator * inverse; // inverse mod 2^256

            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
            // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
            // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
            // is no longer required.
            result = prod0 * inverse;
            return result;
        }
    }

    /**
     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
        uint256 result = mulDiv(x, y, denominator);
        if (unsignedRoundsUp(rounding) && mulmod(x, y, denominator) > 0) {
            result += 1;
        }
        return result;
    }

    /**
     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded
     * towards zero.
     *
     * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
     */
    function sqrt(uint256 a) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
        //
        // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
        //
        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
        //
        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
        uint256 result = 1 << (log2(a) >> 1);

        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
        // into the expected uint128 result.
        unchecked {
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            return min(result, a / result);
        }
    }

    /**
     * @notice Calculates sqrt(a), following the selected rounding direction.
     */
    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = sqrt(a);
            return result + (unsignedRoundsUp(rounding) && result * result < a ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 2 of a positive value rounded towards zero.
     * Returns 0 if given 0.
     */
    function log2(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 128;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 64;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 32;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 16;
            }
            if (value >> 8 > 0) {
                value >>= 8;
                result += 8;
            }
            if (value >> 4 > 0) {
                value >>= 4;
                result += 4;
            }
            if (value >> 2 > 0) {
                value >>= 2;
                result += 2;
            }
            if (value >> 1 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log2(value);
            return result + (unsignedRoundsUp(rounding) && 1 << result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 10 of a positive value rounded towards zero.
     * Returns 0 if given 0.
     */
    function log10(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >= 10 ** 64) {
                value /= 10 ** 64;
                result += 64;
            }
            if (value >= 10 ** 32) {
                value /= 10 ** 32;
                result += 32;
            }
            if (value >= 10 ** 16) {
                value /= 10 ** 16;
                result += 16;
            }
            if (value >= 10 ** 8) {
                value /= 10 ** 8;
                result += 8;
            }
            if (value >= 10 ** 4) {
                value /= 10 ** 4;
                result += 4;
            }
            if (value >= 10 ** 2) {
                value /= 10 ** 2;
                result += 2;
            }
            if (value >= 10 ** 1) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log10(value);
            return result + (unsignedRoundsUp(rounding) && 10 ** result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 256 of a positive value rounded towards zero.
     * Returns 0 if given 0.
     *
     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
     */
    function log256(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 16;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 8;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 4;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 2;
            }
            if (value >> 8 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 256, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log256(value);
            return result + (unsignedRoundsUp(rounding) && 1 << (result << 3) < value ? 1 : 0);
        }
    }

    /**
     * @dev Returns whether a provided rounding mode is considered rounding up for unsigned integers.
     */
    function unsignedRoundsUp(Rounding rounding) internal pure returns (bool) {
        return uint8(rounding) % 2 == 1;
    }
}

// SPDX-License-Identifier: Apache-2.0

pragma solidity ^0.8.21;

import {Context} from "@openzeppelin/contracts/utils/Context.sol";
import "../library/RMRKErrors.sol";

/**
 * @title Ownable
 * @author RMRK team
 * @notice A minimal ownable smart contract or owner and contributors.
 * @dev This smart contract is based on "openzeppelin's access/Ownable.sol".
 */
contract Ownable is Context {
    address private _owner;
    mapping(address => uint256) private _contributors;

    /**
     * @notice Used to anounce the transfer of ownership.
     * @param previousOwner Address of the account that transferred their ownership role
     * @param newOwner Address of the account receiving the ownership role
     */
    event OwnershipTransferred(
        address indexed previousOwner,
        address indexed newOwner
    );

    /**
     * @notice Event that signifies that an address was granted contributor role or that the permission has been
     *  revoked.
     * @dev This can only be triggered by a current owner, so there is no need to include that information in the event.
     * @param contributor Address of the account that had contributor role status updated
     * @param isContributor A boolean value signifying whether the role has been granted (`true`) or revoked (`false`)
     */
    event ContributorUpdate(address indexed contributor, bool isContributor);

    /**
     * @dev Reverts if called by any account other than the owner or an approved contributor.
     */
    modifier onlyOwnerOrContributor() {
        _onlyOwnerOrContributor();
        _;
    }

    /**
     * @dev Reverts if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _onlyOwner();
        _;
    }

    /**
     * @dev Initializes the contract by setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @notice Returns the address of the current owner.
     * @return owner_ Address of the current owner
     */
    function owner() public view virtual returns (address owner_) {
        owner_ = _owner;
    }

    /**
     * @notice Leaves the contract without owner. Functions using the `onlyOwner` modifier will be disabled.
     * @dev Can only be called by the current owner.
     * @dev Renouncing ownership will leave the contract without an owner, thereby removing any functionality that is
     *  only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @notice Transfers ownership of the contract to a new owner.
     * @dev Can only be called by the current owner.
     * @param newOwner Address of the new owner's account
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        if (newOwner == address(0)) revert RMRKNewOwnerIsZeroAddress();
        _transferOwnership(newOwner);
    }

    /**
     * @notice Transfers ownership of the contract to a new owner.
     * @dev Internal function without access restriction.
     * @dev Emits ***OwnershipTransferred*** event.
     * @param newOwner Address of the new owner's account
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }

    /**
     * @notice Adds or removes a contributor to the smart contract.
     * @dev Can only be called by the owner.
     * @dev Emits ***ContributorUpdate*** event.
     * @param contributor Address of the contributor's account
     * @param grantRole A boolean value signifying whether the contributor role is being granted (`true`) or revoked
     *  (`false`)
     */
    function manageContributor(
        address contributor,
        bool grantRole
    ) external onlyOwner {
        if (contributor == address(0)) revert RMRKNewContributorIsZeroAddress();
        grantRole
            ? _contributors[contributor] = 1
            : _contributors[contributor] = 0;
        emit ContributorUpdate(contributor, grantRole);
    }

    /**
     * @notice Used to check if the address is one of the contributors.
     * @param contributor Address of the contributor whose status we are checking
     * @return isContributor_ Boolean value indicating whether the address is a contributor or not
     */
    function isContributor(
        address contributor
    ) public view returns (bool isContributor_) {
        isContributor_ = _contributors[contributor] == 1;
    }

    /**
     * @notice Used to verify that the caller is either the owner or a contributor.
     * @dev If the caller is not the owner or a contributor, the execution will be reverted.
     */
    function _onlyOwnerOrContributor() private view {
        if (owner() != _msgSender() && !isContributor(_msgSender()))
            revert RMRKNotOwnerOrContributor();
    }

    /**
     * @notice Used to verify that the caller is the owner.
     * @dev If the caller is not the owner, the execution will be reverted.
     */
    function _onlyOwner() private view {
        if (owner() != _msgSender()) revert RMRKNotOwner();
    }
}

// SPDX-License-Identifier: Apache-2.0

pragma solidity ^0.8.21;

import {IERC165} from "@openzeppelin/contracts/utils/introspection/IERC165.sol";
import {IERC2981} from "@openzeppelin/contracts/interfaces/IERC2981.sol";
import {
    IERC721Metadata
} from "@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol";
import {
    RMRKMinifiedEquippable
} from "../../RMRK/equippable/RMRKMinifiedEquippable.sol";
import {RMRKImplementationBase} from "../utils/RMRKImplementationBase.sol";

/**
 * @title RMRKAbstractEquippable
 * @author RMRK team
 * @notice Abstract implementation of RMRK equipable module.
 */
abstract contract RMRKAbstractEquippable is
    RMRKImplementationBase,
    RMRKMinifiedEquippable
{
    /**
     * @notice Used to add an asset to a token.
     * @dev If the given asset is already added to the token, the execution will be reverted.
     * @dev If the asset ID is invalid, the execution will be reverted.
     * @dev If the token already has the maximum amount of pending assets (128), the execution will be
     *  reverted.
     * @param tokenId ID of the token to add the asset to
     * @param assetId ID of the asset to add to the token
     * @param replacesAssetWithId ID of the asset to replace from the token's list of active assets
     */
    function addAssetToToken(
        uint256 tokenId,
        uint64 assetId,
        uint64 replacesAssetWithId
    ) public virtual onlyOwnerOrContributor {
        _addAssetToToken(tokenId, assetId, replacesAssetWithId);
    }

    /**
     * @notice Used to add an equippable asset entry.
     * @dev The ID of the asset is automatically assigned to be the next available asset ID.
     * @param equippableGroupId ID of the equippable group
     * @param catalogAddress Address of the `Catalog` smart contract this asset belongs to
     * @param metadataURI Metadata URI of the asset
     * @param partIds An array of IDs of fixed and slot parts to be included in the asset
     * @return assetId The ID of the newly added asset
     */
    function addEquippableAssetEntry(
        uint64 equippableGroupId,
        address catalogAddress,
        string memory metadataURI,
        uint64[] memory partIds
    ) public virtual onlyOwnerOrContributor returns (uint256 assetId) {
        unchecked {
            ++_totalAssets;
        }
        _addAssetEntry(
            uint64(_totalAssets),
            equippableGroupId,
            catalogAddress,
            metadataURI,
            partIds
        );
        assetId = _totalAssets;
    }

    /**
     * @notice Used to add a asset entry.
     * @dev The ID of the asset is automatically assigned to be the next available asset ID.
     * @param metadataURI Metadata URI of the asset
     * @return assetId ID of the newly added asset
     */
    function addAssetEntry(
        string memory metadataURI
    ) public virtual onlyOwnerOrContributor returns (uint256 assetId) {
        unchecked {
            ++_totalAssets;
        }
        _addAssetEntry(uint64(_totalAssets), metadataURI);
        assetId = _totalAssets;
    }

    /**
     * @notice Used to declare that the assets belonging to a given `equippableGroupId` are equippable into the `Slot`
     *  associated with the `partId` of the collection at the specified `parentAddress`
     * @param equippableGroupId ID of the equippable group
     * @param parentAddress Address of the parent into which the equippable group can be equipped into
     * @param partId ID of the `Slot` that the items belonging to the equippable group can be equipped into
     */
    function setValidParentForEquippableGroup(
        uint64 equippableGroupId,
        address parentAddress,
        uint64 partId
    ) public virtual onlyOwnerOrContributor {
        _setValidParentForEquippableGroup(
            equippableGroupId,
            parentAddress,
            partId
        );
    }

    /**
     * @inheritdoc IERC165
     */
    function supportsInterface(
        bytes4 interfaceId
    ) public view virtual override returns (bool) {
        return
            super.supportsInterface(interfaceId) ||
            interfaceId == type(IERC2981).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            interfaceId == RMRK_INTERFACE();
    }

    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual override {
        super._beforeTokenTransfer(from, to, tokenId);
        if (to == address(0)) {
            unchecked {
                _totalSupply -= 1;
            }
        }
    }

    function _afterAddAssetToToken(
        uint256 tokenId,
        uint64 assetId,
        uint64 replacesAssetWithId
    ) internal virtual override {
        super._afterAddAssetToToken(tokenId, assetId, replacesAssetWithId);
        // This relies on no other auto accept mechanism being in place.
        // We auto accept the first ever asset or any asset added by the token owner.
        // This is done to allow a meta factory to mint, add assets and accept them in one transaction.
        if (
            _activeAssets[tokenId].length == 0 ||
            _msgSender() == ownerOf(tokenId)
        ) {
            _acceptAsset(tokenId, _pendingAssets[tokenId].length - 1, assetId);
        }
    }
}

// SPDX-License-Identifier: Apache-2.0

pragma solidity ^0.8.21;

/**
 * @title RMRKCore
 * @author RMRK team
 * @notice Smart contract of the RMRK core module.
 * @dev This is currently just a passthrough contract which allows for granular editing of base-level ERC721 functions.
 */
contract RMRKCore {
    string private constant _VERSION = "2.5.5";
    bytes4 private constant _RMRK_INTERFACE = 0x524D524B; // "RMRK" in ASCII hex

    /**
     * @notice Version of the @rmrk-team/evm-contracts package
     * @return version Version identifier for implementations of the @rmrk-team/evm-contracts package
     */
    function VERSION() public pure returns (string memory version) {
        version = _VERSION;
    }

    /**
     * @notice Interface identifier of the @rmrk-team/evm-contracts package
     * @return rmrkInterface Interface identifier for implementations of the @rmrk-team/evm-contracts package
     */
    function RMRK_INTERFACE() public pure returns (bytes4 rmrkInterface) {
        rmrkInterface = _RMRK_INTERFACE;
    }
}

// SPDX-License-Identifier: Apache-2.0

pragma solidity ^0.8.21;

/// @title RMRKErrors
/// @author RMRK team
/// @notice A collection of errors used in the RMRK suite
/// @dev Errors are kept in a centralised file in order to provide a central point of reference and to avoid error
///  naming collisions due to inheritance

/// Attempting to grant the token to 0x0 address
error ERC721AddressZeroIsNotaValidOwner();
/// Attempting to grant approval to the current owner of the token
error ERC721ApprovalToCurrentOwner();
/// Attempting to grant approval when not being owner or approved for all should not be permitted
error ERC721ApproveCallerIsNotOwnerNorApprovedForAll();
/// Attempting to grant approval to self
error ERC721ApproveToCaller();
/// Attempting to use an invalid token ID
error ERC721InvalidTokenId();
/// Attempting to mint to 0x0 address
error ERC721MintToTheZeroAddress();
/// Attempting to manage a token without being its owner or approved by the owner
error ERC721NotApprovedOrOwner();
/// Attempting to mint an already minted token
error ERC721TokenAlreadyMinted();
/// Attempting to transfer the token from an address that is not the owner
error ERC721TransferFromIncorrectOwner();
/// Attempting to safe transfer to an address that is unable to receive the token
error ERC721TransferToNonReceiverImplementer();
/// Attempting to transfer the token to a 0x0 address
error ERC721TransferToTheZeroAddress();
/// Attempting to grant approval of assets to their current owner
error RMRKApprovalForAssetsToCurrentOwner();
/// Attempting to grant approval of assets without being the caller or approved for all
error RMRKApproveForAssetsCallerIsNotOwnerNorApprovedForAll();
/// Attempting to incorrectly configue a Catalog item
error RMRKBadConfig();
/// Attempting to set the priorities with an array of length that doesn't match the length of active assets array
error RMRKBadPriorityListLength();
/// Attempting to add an asset entry with `Part`s, without setting the `Catalog` address
error RMRKCatalogRequiredForParts();
/// Attempting to transfer a soulbound (non-transferrable) token
error RMRKCannotTransferSoulbound();
/// Attempting to accept a child that has already been accepted
error RMRKChildAlreadyExists();
/// Attempting to interact with a child, using index that is higher than the number of children
error RMRKChildIndexOutOfRange();
/// Attempting to find the index of a child token on a parent which does not own it.
error RMRKChildNotFoundInParent();
/// Attempting to equip a `Part` with a child not approved by the Catalog
error RMRKEquippableEquipNotAllowedByCatalog();
/// Attempting to use ID 0, which is not supported
/// @dev The ID 0 in RMRK suite is reserved for empty values. Guarding against its use ensures the expected operation
error RMRKIdZeroForbidden();
/// Attempting to interact with an asset, using index greater than number of assets
error RMRKIndexOutOfRange();
/// Attempting to reclaim a child that can't be reclaimed
error RMRKInvalidChildReclaim();
/// Attempting to interact with an end-user account when the contract account is expected
error RMRKIsNotContract();
/// Attempting to interact with a contract that had its operation locked
error RMRKLocked();
/// Attempting to add a pending child after the number of pending children has reached the limit (default limit is 128)
error RMRKMaxPendingChildrenReached();
/// Attempting to add a pending asset after the number of pending assets has reached the limit (default limit is
///  128)
error RMRKMaxPendingAssetsReached();
/// Attempting to burn a total number of recursive children higher than maximum set
/// @param childContract Address of the collection smart contract in which the maximum number of recursive burns was reached
/// @param childId ID of the child token at which the maximum number of recursive burns was reached
error RMRKMaxRecursiveBurnsReached(address childContract, uint256 childId);
/// Attempting to mint a number of tokens that would cause the total supply to be greater than maximum supply
error RMRKMintOverMax();
/// Attempting to mint zero tokens
error RMRKMintZero();
/// Attempting to pass complementary arrays of different lengths
error RMRKMismachedArrayLength();
/// Attempting to transfer a child before it is unequipped
error RMRKMustUnequipFirst();
/// Attempting to nest a child over the nestable limit (current limit is 100 levels of nesting)
error RMRKNestableTooDeep();
/// Attempting to nest the token to own descendant, which would create a loop and leave the looped tokens in limbo
error RMRKNestableTransferToDescendant();
/// Attempting to nest the token to a smart contract that doesn't support nesting
error RMRKNestableTransferToNonRMRKNestableImplementer();
/// Attempting to nest the token into itself
error RMRKNestableTransferToSelf();
/// Attempting to interact with an asset that can not be found
error RMRKNoAssetMatchingId();
/// Attempting to manage an asset without owning it or having been granted permission by the owner to do so
error RMRKNotApprovedForAssetsOrOwner();
/// Attempting to interact with a token without being its owner or having been granted permission by the
///  owner to do so
/// @dev When a token is nested, only the direct owner (NFT parent) can mange it. In that case, approved addresses are
///  not allowed to manage it, in order to ensure the expected behaviour
error RMRKNotApprovedOrDirectOwner();
/// Attempting to compose an asset wihtout having an associated Catalog
error RMRKNotComposableAsset();
/// Attempting to unequip an item that isn't equipped
error RMRKNotEquipped();
/// Attempting to interact with a management function without being the smart contract's owner
error RMRKNotOwner();
/// Attempting to interact with a function without being the owner or contributor of the collection
error RMRKNotOwnerOrContributor();
/// Attempting to transfer the ownership to the 0x0 address
error RMRKNewOwnerIsZeroAddress();
/// Attempting to assign a 0x0 address as a contributor
error RMRKNewContributorIsZeroAddress();
/// Attempting an operation requiring the token being nested, while it is not
error RMRKParentIsNotNFT();
/// Attempting to add a `Part` with an ID that is already used
error RMRKPartAlreadyExists();
/// Attempting to use a `Part` that doesn't exist
error RMRKPartDoesNotExist();
/// Attempting to use a `Part` that is `Fixed` when `Slot` kind of `Part` should be used
error RMRKPartIsNotSlot();
/// Attempting to interact with a pending child using an index greater than the size of pending array
error RMRKPendingChildIndexOutOfRange();
/// Attempting to add an asset using an ID that has already been used
error RMRKAssetAlreadyExists();
/// Attempting to equip an item into a slot that already has an item equipped
error RMRKSlotAlreadyUsed();
/// Attempting to equip an item into a `Slot` that the target asset does not implement
error RMRKTargetAssetCannotReceiveSlot();
/// Attempting to equip a child into a `Slot` and parent that the child's collection doesn't support
error RMRKTokenCannotBeEquippedWithAssetIntoSlot();
/// Attempting to compose a NFT of a token without active assets
error RMRKTokenDoesNotHaveAsset();
/// Attempting to determine the asset with the top priority on a token without assets
error RMRKTokenHasNoAssets();
/// Attempting to accept or transfer a child which does not match the one at the specified index
error RMRKUnexpectedChildId();
/// Attempting to reject all pending assets but more assets than expected are pending
error RMRKUnexpectedNumberOfAssets();
/// Attempting to reject all pending children but children assets than expected are pending
error RMRKUnexpectedNumberOfChildren();
/// Attempting to accept or reject an asset which does not match the one at the specified index
error RMRKUnexpectedAssetId();
/// Attempting an operation expecting a parent to the token which is not the actual one
error RMRKUnexpectedParent();
/// Attempting not to pass an empty array of equippable addresses when adding or setting the equippable addresses
error RMRKZeroLengthIdsPassed();
/// Attempting to set the royalties to a value higher than 100% (10000 in basis points)
error RMRKRoyaltiesTooHigh();
/// Attempting to do a bulk operation on a token that is not owned by the caller
error RMRKCanOnlyDoBulkOperationsOnOwnedTokens();
/// Attempting to do a bulk operation with multiple tokens at a time
error RMRKCanOnlyDoBulkOperationsWithOneTokenAtATime();
/// Attempting to pay with native token with a value different than expected
error RMRKWrongValueSent();
// Attempting to send native token to a recipient that is unable to receive it
error TransferFailed();

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.21;

import {Ownable} from "../../RMRK/access/Ownable.sol";
import "../../RMRK/library/RMRKErrors.sol";
import {RMRKRoyalties} from "../../RMRK/extension/RMRKRoyalties.sol";

/**
 * @title RMRKImplementationBase
 * @author RMRK team
 * @notice Smart contract of the RMRK minting utils module.
 * @dev This smart contract includes the top-level utilities for managing minting and implements Ownable by default.
 */
abstract contract RMRKImplementationBase is RMRKRoyalties, Ownable {
    string internal _contractURI;
    string private _name;
    string private _symbol;

    uint256 private _nextId;
    uint256 internal _totalSupply;
    uint256 internal _maxSupply;
    uint256 internal _totalAssets;

    /**
     * @notice Initializes the smart contract with a given maximum supply and minting price.
     * @param name_ Name of the token collection
     * @param symbol_ Symbol of the token collection
     * @param contractURI_ The collection metadata URI
     * @param maxSupply_ The maximum supply of tokens
     * @param royaltyRecipient Address to which royalties should be sent
     * @param royaltyPercentageBps The royalty percentage expressed in basis points
     */
    constructor(
        string memory name_,
        string memory symbol_,
        string memory contractURI_,
        uint256 maxSupply_,
        address royaltyRecipient,
        uint256 royaltyPercentageBps
    ) RMRKRoyalties(royaltyRecipient, royaltyPercentageBps) {
        _name = name_;
        _symbol = symbol_;
        _contractURI = contractURI_;
        _maxSupply = maxSupply_;
    }

    /**
     * @notice Used to retrieve the total supply of the tokens in a collection.
     * @return totalSupply_ The number of tokens in a collection
     */
    function totalSupply() public view virtual returns (uint256 totalSupply_) {
        totalSupply_ = _totalSupply;
    }

    /**
     * @notice Used to retrieve the maximum supply of the collection.
     * @return maxSupply_ The maximum supply of tokens in the collection
     */
    function maxSupply() public view virtual returns (uint256 maxSupply_) {
        maxSupply_ = _maxSupply;
    }

    /**
     * @notice Used to retrieve the total number of assets.
     * @return totalAssets_ The total number of assets
     */
    function totalAssets() public view virtual returns (uint256 totalAssets_) {
        totalAssets_ = _totalAssets;
    }

    /**
     * @notice Used to retrieve the metadata URI of the collection.
     * @return contractURI_ string The metadata URI of the collection
     */
    function contractURI()
        public
        view
        virtual
        returns (string memory contractURI_)
    {
        contractURI_ = _contractURI;
    }

    /**
     * @notice Used to retrieve the collection name.
     * @return name_ Name of the collection
     */
    function name() public view virtual returns (string memory name_) {
        name_ = _name;
    }

    /**
     * @notice Used to retrieve the collection symbol.
     * @return symbol_ Symbol of the collection
     */
    function symbol() public view virtual returns (string memory symbol_) {
        symbol_ = _symbol;
    }

    /**
     * @inheritdoc RMRKRoyalties
     */
    function updateRoyaltyRecipient(
        address newRoyaltyRecipient
    ) public virtual override onlyOwner {
        _setRoyaltyRecipient(newRoyaltyRecipient);
    }

    /**
     * @notice Used to calculate the token IDs of tokens to be minted.
     * @param numToMint Amount of tokens to be minted
     * @return nextToken The ID of the first token to be minted in the current minting cycle
     * @return totalSupplyOffset The ID of the last token to be minted in the current minting cycle
     */
    function _prepareMint(
        uint256 numToMint
    ) internal virtual returns (uint256 nextToken, uint256 totalSupplyOffset) {
        if (numToMint == uint256(0)) revert RMRKMintZero();
        if (numToMint + _nextId > _maxSupply) revert RMRKMintOverMax();

        unchecked {
            nextToken = _nextId + 1;
            _nextId += numToMint;
            _totalSupply += numToMint;
            totalSupplyOffset = _nextId + 1;
        }
    }
}

// SPDX-License-Identifier: Apache-2.0

pragma solidity ^0.8.21;

/**
 * @title RMRKLib
 * @author RMRK team
 * @notice RMRK library smart contract.
 */
library RMRKLib {
    error IndexOutOfBounds();

    /**
     * @notice Used to remove an item from the array using the specified index.
     * @dev The item is removed by replacing it with the last item and removing the last element.
     * @param array An array of items containing the item to be removed
     * @param index Index of the item to remove
     */
    function removeItemByIndex(uint64[] storage array, uint256 index) internal {
        //Check to see if this is already gated by require in all calls
        if (index >= array.length) revert IndexOutOfBounds();
        array[index] = array[array.length - 1];
        array.pop();
    }

    /**
     * @notice Used to determine the index of the item in the array by spedifying its value.
     * @dev This was adapted from Cryptofin-Solidity `arrayUtils`.
     * @dev If the item is not found the index returned will equal `0`.
     * @param A The array containing the item to be found
     * @param a The value of the item to find the index of
     * @return The index of the item in the array
     * @return A boolean value specifying whether the item was found
     */
    function indexOf(
        uint64[] memory A,
        uint64 a
    ) internal pure returns (uint256, bool) {
        uint256 length = A.length;
        for (uint256 i; i < length; ) {
            if (A[i] == a) {
                return (i, true);
            }
            unchecked {
                ++i;
            }
        }
        return (0, false);
    }
}

// SPDX-License-Identifier: Apache-2.0

pragma solidity ^0.8.21;

import {IERC165} from "@openzeppelin/contracts/utils/introspection/IERC165.sol";
import {IERC5773} from "../multiasset/IERC5773.sol";
import {IERC6220} from "../equippable/IERC6220.sol";
import {IERC721} from "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import {
    IERC721Receiver
} from "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";
import {IERC7401} from "../nestable/IERC7401.sol";
import {Context} from "@openzeppelin/contracts/utils/Context.sol";
import {IRMRKCatalog} from "../catalog/IRMRKCatalog.sol";
import {RMRKCore} from "../core/RMRKCore.sol";
import {RMRKLib} from "../library/RMRKLib.sol";
import {ReentrancyGuard} from "../security/ReentrancyGuard.sol";
import "../library/RMRKErrors.sol";

/**
 * @title RMRKMinifiedEquippable
 * @author RMRK team
 * @notice Smart contract of the RMRK Equippable module, without utility internal functions.
 * @dev This includes all the code for MultiAsset, Nestable and Equippable.
 * @dev Most of the code is duplicated from the other legos, this version is created to save size.
 */
contract RMRKMinifiedEquippable is
    ReentrancyGuard,
    Context,
    IERC165,
    IERC721,
    IERC7401,
    IERC6220,
    RMRKCore
{
    using RMRKLib for uint64[];

    uint256 private constant _MAX_LEVELS_TO_CHECK_FOR_INHERITANCE_LOOP = 100;

    // Mapping owner address to token count
    mapping(address => uint256) private _balances;

    // Mapping from token ID to approver address to approved address
    // The approver is necessary so approvals are invalidated for nested children on transfer
    // WARNING: If a child NFT returns to a previous root owner, old permissions would be active again
    mapping(uint256 => mapping(address => address)) private _tokenApprovals;

    // Mapping from owner to operator approvals
    mapping(address => mapping(address => bool)) private _operatorApprovals;

    // ------------------- NESTABLE --------------

    // Mapping from token ID to DirectOwner struct
    mapping(uint256 => DirectOwner) private _RMRKOwners;

    // Mapping of tokenId to array of active children structs
    mapping(uint256 => Child[]) internal _activeChildren;

    // Mapping of tokenId to array of pending children structs
    mapping(uint256 => Child[]) internal _pendingChildren;

    // Mapping of child token address to child token ID to whether they are pending or active on any token
    // We might have a first extra mapping from token ID, but since the same child cannot be nested into multiple tokens
    //  we can strip it for size/gas savings.
    mapping(address => mapping(uint256 => uint256)) internal _childIsInActive;

    // -------------------------- MODIFIERS ----------------------------

    /**
     * @notice Used to verify that the caller is either the owner of the token or approved to manage it by its owner.
     * @dev If the caller is not the owner of the token or approved to manage it by its owner, the execution will be
     *  reverted.
     * @param tokenId ID of the token to check
     */
    function _onlyApprovedOrOwner(uint256 tokenId) internal view {
        address owner = ownerOf(tokenId);
        if (
            !(_msgSender() == owner ||
                isApprovedForAll(owner, _msgSender()) ||
                getApproved(tokenId) == _msgSender())
        ) revert ERC721NotApprovedOrOwner();
    }

    /**
     * @notice Used to verify that the caller is either the owner of the token or approved to manage it by its owner.
     * @param tokenId ID of the token to check
     */
    modifier onlyApprovedOrOwner(uint256 tokenId) {
        _onlyApprovedOrOwner(tokenId);
        _;
    }

    /**
     * @notice Used to verify that the caller is approved to manage the given token or it its direct owner.
     * @dev This does not delegate to ownerOf, which returns the root owner, but rater uses an owner from DirectOwner
     *  struct.
     * @dev The execution is reverted if the caller is not immediate owner or approved to manage the given token.
     * @dev Used for parent-scoped transfers.
     * @param tokenId ID of the token to check.
     */
    function _onlyApprovedOrDirectOwner(uint256 tokenId) internal view {
        (address owner, uint256 parentId, ) = directOwnerOf(tokenId);
        // When the parent is an NFT, only it can do operations. Otherwise, the owner or approved address can
        if (
            (parentId != 0 && _msgSender() != owner) ||
            !(_msgSender() == owner ||
                isApprovedForAll(owner, _msgSender()) ||
                getApproved(tokenId) == _msgSender())
        ) {
            revert RMRKNotApprovedOrDirectOwner();
        }
    }

    /**
     * @notice Used to verify that the caller is approved to manage the given token or is its direct owner.
     * @param tokenId ID of the token to check
     */
    modifier onlyApprovedOrDirectOwner(uint256 tokenId) {
        _onlyApprovedOrDirectOwner(tokenId);
        _;
    }

    // ------------------------------- ERC721 ---------------------------------

    /**
     * @notice Used to retrieve the number of tokens in `owner`'s account.
     * @param owner Address of the account being checked
     * @return balance The balance of the given account
     */
    function balanceOf(
        address owner
    ) public view virtual returns (uint256 balance) {
        if (owner == address(0)) revert ERC721AddressZeroIsNotaValidOwner();
        balance = _balances[owner];
    }

    ////////////////////////////////////////
    //              TRANSFERS
    ////////////////////////////////////////

    /**
     * @notice Transfers a given token from `from` to `to`.
     * @dev Requirements:
     *
     *  - `from` cannot be the zero address.
     *  - `to` cannot be the zero address.
     *  - `tokenId` token must be owned by `from`.
     *  - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * @dev Emits a {Transfer} event.
     * @param from Address from which to transfer the token from
     * @param to Address to which to transfer the token to
     * @param tokenId ID of the token to transfer
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual onlyApprovedOrDirectOwner(tokenId) {
        _transfer(from, to, tokenId, "");
    }

    /**
     * @notice Used to safely transfer a given token token from `from` to `to`.
     * @dev Requirements:
     *
     *  - `from` cannot be the zero address.
     *  - `to` cannot be the zero address.
     *  - `tokenId` token must exist and be owned by `from`.
     *  - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *  - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     * @dev Emits a {Transfer} event.
     * @param from Address to transfer the tokens from
     * @param to Address to transfer the tokens to
     * @param tokenId ID of the token to transfer
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual {
        safeTransferFrom(from, to, tokenId, "");
    }

    /**
     * @notice Used to safely transfer a given token token from `from` to `to`.
     * @dev Requirements:
     *
     *  - `from` cannot be the zero address.
     *  - `to` cannot be the zero address.
     *  - `tokenId` token must exist and be owned by `from`.
     *  - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *  - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     * @dev Emits a {Transfer} event.
     * @param from Address to transfer the tokens from
     * @param to Address to transfer the tokens to
     * @param tokenId ID of the token to transfer
     * @param data Additional data without a specified format to be sent along with the token transaction
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory data
    ) public virtual onlyApprovedOrDirectOwner(tokenId) {
        _transfer(from, to, tokenId, data);
        if (!_checkOnERC721Received(from, to, tokenId, data))
            revert ERC721TransferToNonReceiverImplementer();
    }

    /**
     * @inheritdoc IERC7401
     */
    function nestTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        uint256 destinationId,
        bytes memory data
    ) public virtual onlyApprovedOrDirectOwner(tokenId) {
        (address immediateOwner, uint256 parentId, ) = directOwnerOf(tokenId);
        if (immediateOwner != from) revert ERC721TransferFromIncorrectOwner();
        if (to == address(this) && tokenId == destinationId)
            revert RMRKNestableTransferToSelf();

        _checkDestination(to);
        _checkForInheritanceLoop(tokenId, to, destinationId);

        _beforeTokenTransfer(from, to, tokenId);
        _beforeNestedTokenTransfer(
            immediateOwner,
            to,
            parentId,
            destinationId,
            tokenId,
            data
        );
        _balances[from] -= 1;
        _updateOwnerAndClearApprovals(tokenId, destinationId, to);
        _balances[to] += 1;

        // Sending to NFT:
        _sendToNFT(immediateOwner, to, parentId, destinationId, tokenId, data);
    }

    /**
     * @notice Used to transfer the token from `from` to `to`.
     * @dev As opposed to {transferFrom}, this imposes no restrictions on msg.sender
     * @dev Requirements:
     *
     *  - `to` cannot be the zero address.
     *  - `tokenId` token must be owned by `from`.
     * @dev Emits a {Transfer} event.
     * @param from Address of the account currently owning the given token
     * @param to Address to transfer the token to
     * @param tokenId ID of the token to transfer
     * @param data Additional data with no specified format, sent in call to `to`
     */
    function _transfer(
        address from,
        address to,
        uint256 tokenId,
        bytes memory data
    ) internal virtual {
        (address immediateOwner, uint256 parentId, ) = directOwnerOf(tokenId);
        if (immediateOwner != from) revert ERC721TransferFromIncorrectOwner();
        if (to == address(0)) revert ERC721TransferToTheZeroAddress();

        _beforeTokenTransfer(from, to, tokenId);
        _beforeNestedTokenTransfer(from, to, parentId, 0, tokenId, data);

        _balances[from] -= 1;
        _updateOwnerAndClearApprovals(tokenId, 0, to);
        _balances[to] += 1;

        emit Transfer(from, to, tokenId);
        emit NestTransfer(from, to, parentId, 0, tokenId);

        _afterTokenTransfer(from, to, tokenId);
        _afterNestedTokenTransfer(from, to, parentId, 0, tokenId, data);
    }

    /**
     * @notice Used to send a token to another token.
     * @dev If the token being sent is currently owned by an externally owned account, the `parentId` should equal `0`.
     * @dev Emits {Transfer} event.
     * @dev Emits {NestTransfer} event.
     * @param from Address from which the token is being sent
     * @param to Address of the collection smart contract of the token to receive the given token
     * @param parentId ID of the current parent token of the token being sent
     * @param destinationId ID of the tokento receive the token being sent
     * @param tokenId ID of the token being sent
     * @param data Additional data with no specified format, sent in the addChild call
     */
    function _sendToNFT(
        address from,
        address to,
        uint256 parentId,
        uint256 destinationId,
        uint256 tokenId,
        bytes memory data
    ) private {
        IERC7401 destContract = IERC7401(to);
        destContract.addChild(destinationId, tokenId, data);

        emit Transfer(from, to, tokenId);
        emit NestTransfer(from, to, parentId, destinationId, tokenId);

        _afterTokenTransfer(from, to, tokenId);
        _afterNestedTokenTransfer(
            from,
            to,
            parentId,
            destinationId,
            tokenId,
            data
        );
    }

    /**
     * @notice Used to check if nesting a given token into a specified token would create an inheritance loop.
     * @dev If a loop would occur, the tokens would be unmanageable, so the execution is reverted if one is detected.
     * @dev The check for inheritance loop is bounded to guard against too much gas being consumed.
     * @param currentId ID of the token that would be nested
     * @param targetContract Address of the collection smart contract of the token into which the given token would be
     *  nested
     * @param targetId ID of the token into which the given token would be nested
     */
    function _checkForInheritanceLoop(
        uint256 currentId,
        address targetContract,
        uint256 targetId
    ) private view {
        for (uint256 i; i < _MAX_LEVELS_TO_CHECK_FOR_INHERITANCE_LOOP; ) {
            (
                address nextOwner,
                uint256 nextOwnerTokenId,
                bool isNft
            ) = IERC7401(targetContract).directOwnerOf(targetId);
            // If there's a final address, we're good. There's no loop.
            if (!isNft) {
                return;
            }
            // Ff the current nft is an ancestor at some point, there is an inheritance loop
            if (nextOwner == address(this) && nextOwnerTokenId == currentId) {
                revert RMRKNestableTransferToDescendant();
            }
            // We reuse the parameters to save some contract size
            targetContract = nextOwner;
            targetId = nextOwnerTokenId;
            unchecked {
                ++i;
            }
        }
        revert RMRKNestableTooDeep();
    }

    ////////////////////////////////////////
    //              MINTING
    ////////////////////////////////////////

    /**
     * @notice Used to safely mint the token to the specified address while passing the additional data to contract
     *  recipients.
     * @param to Address to which to mint the token
     * @param tokenId ID of the token to mint
     * @param data Additional data to send with the tokens
     */
    function _safeMint(
        address to,
        uint256 tokenId,
        bytes memory data
    ) internal virtual {
        _innerMint(to, tokenId, 0, data);

        emit Transfer(address(0), to, tokenId);
        emit NestTransfer(address(0), to, 0, 0, tokenId);

        _afterTokenTransfer(address(0), to, tokenId);
        _afterNestedTokenTransfer(address(0), to, 0, 0, tokenId, data);
        if (!_checkOnERC721Received(address(0), to, tokenId, data))
            revert ERC721TransferToNonReceiverImplementer();
    }

    /**
     * @notice Used to mint a child token to a given parent token.
     * @param to Address of the collection smart contract of the token into which to mint the child token
     * @param tokenId ID of the token to mint
     * @param destinationId ID of the token into which to mint the new child token
     * @param data Additional data with no specified format, sent in the addChild call
     */
    function _nestMint(
        address to,
        uint256 tokenId,
        uint256 destinationId,
        bytes memory data
    ) internal virtual {
        _checkDestination(to);
        _innerMint(to, tokenId, destinationId, data);
        _sendToNFT(address(0), to, 0, destinationId, tokenId, data);
    }

    /**
     * @notice Used to mint a child token into a given parent token.
     * @dev Requirements:
     *
     *  - `to` cannot be the zero address.
     *  - `tokenId` must not exist.
     *  - `tokenId` must not be `0`.
     * @param to Address of the collection smart contract of the token into which to mint the child token
     * @param tokenId ID of the token to mint
     * @param destinationId ID of the token into which to mint the new token
     * @param data Additional data with no specified format, sent in call to `to`
     */
    function _innerMint(
        address to,
        uint256 tokenId,
        uint256 destinationId,
        bytes memory data
    ) private {
        if (to == address(0)) revert ERC721MintToTheZeroAddress();
        if (_exists(tokenId)) revert ERC721TokenAlreadyMinted();
        if (tokenId == uint256(0)) revert RMRKIdZeroForbidden();

        _beforeTokenTransfer(address(0), to, tokenId);
        _beforeNestedTokenTransfer(
            address(0),
            to,
            0,
            destinationId,
            tokenId,
            data
        );

        _balances[to] += 1;
        _RMRKOwners[tokenId] = DirectOwner({
            ownerAddress: to,
            tokenId: destinationId
        });
    }

    ////////////////////////////////////////
    //              Ownership
    ////////////////////////////////////////

    /**
     * @inheritdoc IERC7401
     */
    function ownerOf(
        uint256 tokenId
    ) public view virtual override(IERC7401, IERC721) returns (address owner_) {
        (address owner, uint256 ownerTokenId, bool isNft) = directOwnerOf(
            tokenId
        );
        if (isNft) {
            owner = IERC7401(owner).ownerOf(ownerTokenId);
        }
        owner_ = owner;
    }

    /**
     * @inheritdoc IERC7401
     */
    function directOwnerOf(
        uint256 tokenId
    )
        public
        view
        virtual
        returns (address owner_, uint256 parentId, bool isNFT)
    {
        DirectOwner memory owner = _RMRKOwners[tokenId];
        if (owner.ownerAddress == address(0)) revert ERC721InvalidTokenId();

        owner_ = owner.ownerAddress;
        parentId = owner.tokenId;
        isNFT = owner.tokenId != 0;
    }

    ////////////////////////////////////////
    //              BURNING
    ////////////////////////////////////////

    /**
     * @notice Used to burn a given token.
     * @dev In case the token has any child tokens, the execution will be reverted.
     * @param tokenId ID of the token to burn
     */
    function burn(uint256 tokenId) public virtual {
        burn(tokenId, 0);
    }

    /**
     * @inheritdoc IERC7401
     */
    function burn(
        uint256 tokenId,
        uint256 maxChildrenBurns
    )
        public
        virtual
        onlyApprovedOrDirectOwner(tokenId)
        returns (uint256 burnedChildren)
    {
        (address immediateOwner, uint256 parentId, ) = directOwnerOf(tokenId);
        address rootOwner = ownerOf(tokenId);

        _beforeTokenTransfer(immediateOwner, address(0), tokenId);
        _beforeNestedTokenTransfer(
            immediateOwner,
            address(0),
            parentId,
            0,
            tokenId,
            ""
        );

        _balances[immediateOwner] -= 1;
        _approve(address(0), tokenId);
        _approveForAssets(address(0), tokenId);

        Child[] memory children = childrenOf(tokenId);

        delete _activeChildren[tokenId];
        delete _pendingChildren[tokenId];
        delete _tokenApprovals[tokenId][rootOwner];

        uint256 pendingRecursiveBurns;

        uint256 length = children.length; //gas savings
        for (uint256 i; i < length; ) {
            if (burnedChildren >= maxChildrenBurns)
                revert RMRKMaxRecursiveBurnsReached(
                    children[i].contractAddress,
                    children[i].tokenId
                );
            delete _childIsInActive[children[i].contractAddress][
                children[i].tokenId
            ];
            unchecked {
                // At this point we know pendingRecursiveBurns must be at least 1
                pendingRecursiveBurns = maxChildrenBurns - burnedChildren;
            }
            // We substract one to the next level to count for the token being burned, then add it again on returns
            // This is to allow the behavior of 0 recursive burns meaning only the current token is deleted.
            burnedChildren +=
                IERC7401(children[i].contractAddress).burn(
                    children[i].tokenId,
                    pendingRecursiveBurns - 1
                ) +
                1;
            unchecked {
                ++i;
            }
        }
        // Can't remove before burning child since child will call back to get root owner
        delete _RMRKOwners[tokenId];

        emit Transfer(immediateOwner, address(0), tokenId);
        emit NestTransfer(immediateOwner, address(0), parentId, 0, tokenId);

        _afterTokenTransfer(immediateOwner, address(0), tokenId);
        _afterNestedTokenTransfer(
            immediateOwner,
            address(0),
            parentId,
            0,
            tokenId,
            ""
        );
    }

    ////////////////////////////////////////
    //              APPROVALS
    ////////////////////////////////////////

    /**
     * @notice Used to grant a one-time approval to manage one's token.
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * @dev The approval is cleared when the token is transferred.
     * @dev Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     * @dev Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     * @dev Emits an {Approval} event.
     * @param to Address receiving the approval
     * @param tokenId ID of the token for which the approval is being granted
     */
    function approve(address to, uint256 tokenId) public virtual {
        address owner = ownerOf(tokenId);
        if (to == owner) revert ERC721ApprovalToCurrentOwner();

        if (_msgSender() != owner && !isApprovedForAll(owner, _msgSender()))
            revert ERC721ApproveCallerIsNotOwnerNorApprovedForAll();

        _approve(to, tokenId);
    }

    /**
     * @notice Used to retrieve the account approved to manage given token.
     * @dev Requirements:
     *
     *  - `tokenId` must exist.
     * @param tokenId ID of the token to check for approval
     * @return approved Address of the account approved to manage the token
     */
    function getApproved(
        uint256 tokenId
    ) public view virtual returns (address approved) {
        _requireMinted(tokenId);

        approved = _tokenApprovals[tokenId][ownerOf(tokenId)];
    }

    /**
     * @notice Used to approve or remove `operator` as an operator for the caller.
     * @dev Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     * @dev Requirements:
     *
     * - The `operator` cannot be the caller.
     * @dev Emits an {ApprovalForAll} event.
     * @param operator Address of the operator being managed
     * @param approved A boolean value signifying whether the approval is being granted (`true`) or (`revoked`)
     */
    function setApprovalForAll(address operator, bool approved) public virtual {
        if (_msgSender() == operator) revert ERC721ApproveToCaller();
        _operatorApprovals[_msgSender()][operator] = approved;
        emit ApprovalForAll(_msgSender(), operator, approved);
    }

    /**
     * @notice Used to check if the given address is allowed to manage the tokens of the specified address.
     * @param owner Address of the owner of the tokens
     * @param operator Address being checked for approval
     * @return isApproved A boolean value signifying whether the *operator* is allowed to manage the tokens of the *owner* (`true`)
     *  or not (`false`)
     */
    function isApprovedForAll(
        address owner,
        address operator
    ) public view virtual returns (bool isApproved) {
        isApproved = _operatorApprovals[owner][operator];
    }

    /**
     * @notice Used to grant an approval to manage a given token.
     * @dev Emits an {Approval} event.
     * @param to Address to which the approval is being granted
     * @param tokenId ID of the token for which the approval is being granted
     */
    function _approve(address to, uint256 tokenId) internal virtual {
        address owner = ownerOf(tokenId);
        _tokenApprovals[tokenId][owner] = to;
        emit Approval(owner, to, tokenId);
    }

    /**
     * @notice Used to update the owner of the token and clear the approvals associated with the previous owner.
     * @dev The `destinationId` should equal `0` if the new owner is an externally owned account.
     * @param tokenId ID of the token being updated
     * @param destinationId ID of the token to receive the given token
     * @param to Address of account to receive the token
     */
    function _updateOwnerAndClearApprovals(
        uint256 tokenId,
        uint256 destinationId,
        address to
    ) internal {
        _RMRKOwners[tokenId] = DirectOwner({
            ownerAddress: to,
            tokenId: destinationId
        });

        // Clear approvals from the previous owner
        _approve(address(0), tokenId);
        _approveForAssets(address(0), tokenId);
    }

    ////////////////////////////////////////
    //              UTILS
    ////////////////////////////////////////

    /**
     * @notice Used to enforce that the given token has been minted.
     * @dev Reverts if the `tokenId` has not been minted yet.
     * @dev The validation checks whether the owner of a given token is a `0x0` address and considers it not minted if
     *  it is. This means that both tokens that haven't been minted yet as well as the ones that have already been
     *  burned will cause the transaction to be reverted.
     * @param tokenId ID of the token to check
     */
    function _requireMinted(uint256 tokenId) internal view virtual {
        if (!_exists(tokenId)) revert ERC721InvalidTokenId();
    }

    /**
     * @notice Used to check whether the given token exists.
     * @dev Tokens start existing when they are minted (`_mint`) and stop existing when they are burned (`_burn`).
     * @param tokenId ID of the token being checked
     * @return exists A boolean value signifying whether the token exists
     */
    function _exists(
        uint256 tokenId
    ) internal view virtual returns (bool exists) {
        exists = _RMRKOwners[tokenId].ownerAddress != address(0);
    }

    /**
     * @notice Used to invoke {IERC721Receiver-onERC721Received} on a target address.
     * @dev The call is not executed if the target address is not a contract.
     * @param from Address representing the previous owner of the given token
     * @param to Yarget address that will receive the tokens
     * @param tokenId ID of the token to be transferred
     * @param data Optional data to send along with the call
     * @return valid Boolean value signifying whether the call correctly returned the expected magic value
     */
    function _checkOnERC721Received(
        address from,
        address to,
        uint256 tokenId,
        bytes memory data
    ) private returns (bool valid) {
        if (to.code.length != 0) {
            try
                IERC721Receiver(to).onERC721Received(
                    _msgSender(),
                    from,
                    tokenId,
                    data
                )
            returns (bytes4 retval) {
                valid = retval == IERC721Receiver.onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == uint256(0)) {
                    revert ERC721TransferToNonReceiverImplementer();
                } else {
                    /// @solidity memory-safe-assembly
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            valid = true;
        }
    }

    ////////////////////////////////////////
    //      CHILD MANAGEMENT PUBLIC
    ////////////////////////////////////////

    /**
     * @inheritdoc IERC7401
     */
    function addChild(
        uint256 parentId,
        uint256 childId,
        bytes memory data
    ) public virtual {
        _requireMinted(parentId);

        address childAddress = _msgSender();
        if (childAddress.code.length == 0) revert RMRKIsNotContract();

        Child memory child = Child({
            contractAddress: childAddress,
            tokenId: childId
        });

        _beforeAddChild(parentId, childAddress, childId, data);

        uint256 length = pendingChildrenOf(parentId).length;

        if (length < 128) {
            _pendingChildren[parentId].push(child);
        } else {
            revert RMRKMaxPendingChildrenReached();
        }

        // Previous length matches the index for the new child
        emit ChildProposed(parentId, length, childAddress, childId);

        _afterAddChild(parentId, childAddress, childId, data);
    }

    /**
     * @inheritdoc IERC7401
     */
    function acceptChild(
        uint256 parentId,
        uint256 childIndex,
        address childAddress,
        uint256 childId
    ) public virtual onlyApprovedOrOwner(parentId) {
        _acceptChild(parentId, childIndex, childAddress, childId);
    }

    /**
     * @notice Used to accept a pending child token for a given parent token.
     * @dev This moves the child token from parent token's pending child tokens array into the active child tokens
     *  array.
     * @dev Requirements:
     *
     *  - `tokenId` must exist
     *  - `index` must be in range of the pending children array
     * @dev Emits ***ChildAccepted*** event.
     * @param parentId ID of the parent token for which the child token is being accepted
     * @param childIndex Index of a child tokem in the given parent's pending children array
     * @param childAddress Address of the collection smart contract of the child token expected to be located at the
     *  specified index of the given parent token's pending children array
     * @param childId ID of the child token expected to be located at the specified index of the given parent token's
     *  pending children array
     */
    function _acceptChild(
        uint256 parentId,
        uint256 childIndex,
        address childAddress,
        uint256 childId
    ) internal virtual {
        Child memory child = pendingChildOf(parentId, childIndex);
        _checkExpectedChild(child, childAddress, childId);
        if (_childIsInActive[childAddress][childId] != 0)
            revert RMRKChildAlreadyExists();

        _beforeAcceptChild(parentId, childIndex, childAddress, childId);

        // Remove from pending:
        _removeChildByIndex(_pendingChildren[parentId], childIndex);

        // Add to active:
        _activeChildren[parentId].push(child);
        _childIsInActive[childAddress][childId] = 1; // We use 1 as true

        emit ChildAccepted(parentId, childIndex, childAddress, childId);

        _afterAcceptChild(parentId, childIndex, childAddress, childId);
    }

    /**
     * @inheritdoc IERC7401
     */
    function rejectAllChildren(
        uint256 tokenId,
        uint256 maxRejections
    ) public virtual onlyApprovedOrOwner(tokenId) {
        if (_pendingChildren[tokenId].length > maxRejections)
            revert RMRKUnexpectedNumberOfChildren();

        _beforeRejectAllChildren(tokenId);
        delete _pendingChildren[tokenId];
        emit AllChildrenRejected(tokenId);
        _afterRejectAllChildren(tokenId);
    }

    /**
     * @inheritdoc IERC7401
     */
    function transferChild(
        uint256 tokenId,
        address to,
        uint256 destinationId,
        uint256 childIndex,
        address childAddress,
        uint256 childId,
        bool isPending,
        bytes memory data
    ) public virtual onlyApprovedOrOwner(tokenId) {
        Child memory child;
        if (isPending) {
            child = pendingChildOf(tokenId, childIndex);
        } else {
            if (isChildEquipped(tokenId, childAddress, childId))
                revert RMRKMustUnequipFirst();
            child = childOf(tokenId, childIndex);
        }
        _checkExpectedChild(child, childAddress, childId);

        _beforeTransferChild(
            tokenId,
            childIndex,
            childAddress,
            childId,
            isPending,
            data
        );

        if (isPending) {
            _removeChildByIndex(_pendingChildren[tokenId], childIndex);
        } else {
            delete _childIsInActive[childAddress][childId];
            _removeChildByIndex(_activeChildren[tokenId], childIndex);
        }

        if (to != address(0)) {
            if (destinationId == uint256(0)) {
                IERC721(childAddress).safeTransferFrom(
                    address(this),
                    to,
                    childId,
                    data
                );
            } else {
                // Destination is an NFT
                IERC7401(child.contractAddress).nestTransferFrom(
                    address(this),
                    to,
                    child.tokenId,
                    destinationId,
                    data
                );
            }
        }

        emit ChildTransferred(
            tokenId,
            childIndex,
            childAddress,
            childId,
            isPending,
            to == address(0)
        );
        _afterTransferChild(
            tokenId,
            childIndex,
            childAddress,
            childId,
            isPending,
            data
        );
    }

    /**
     * @notice Used to verify that the child being accessed is the intended child.
     * @dev The Child struct consists of the following values:
     *  [
     *      tokenId,
     *      contractAddress
     *  ]
     * @param child A Child struct of a child being accessed
     * @param expectedAddress The address expected to be the one of the child
     * @param expectedId The token ID expected to be the one of the child
     */
    function _checkExpectedChild(
        Child memory child,
        address expectedAddress,
        uint256 expectedId
    ) private pure {
        if (
            expectedAddress != child.contractAddress ||
            expectedId != child.tokenId
        ) revert RMRKUnexpectedChildId();
    }

    ////////////////////////////////////////
    //      CHILD MANAGEMENT GETTERS
    ////////////////////////////////////////

    /**
     * @inheritdoc IERC7401
     */

    function childrenOf(
        uint256 parentId
    ) public view virtual returns (Child[] memory children) {
        children = _activeChildren[parentId];
    }

    /**
     * @inheritdoc IERC7401
     */

    function pendingChildrenOf(
        uint256 parentId
    ) public view virtual returns (Child[] memory children) {
        children = _pendingChildren[parentId];
    }

    /**
     * @inheritdoc IERC7401
     */
    function childOf(
        uint256 parentId,
        uint256 index
    ) public view virtual returns (Child memory child) {
        if (childrenOf(parentId).length <= index)
            revert RMRKChildIndexOutOfRange();
        child = _activeChildren[parentId][index];
    }

    /**
     * @inheritdoc IERC7401
     */
    function pendingChildOf(
        uint256 parentId,
        uint256 index
    ) public view virtual returns (Child memory child) {
        if (pendingChildrenOf(parentId).length <= index)
            revert RMRKPendingChildIndexOutOfRange();
        child = _pendingChildren[parentId][index];
    }

    // HOOKS

    /**
     * @notice Hook that is called before any token transfer. This includes minting and burning.
     * @dev Calling conditions:
     *
     *  - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be transferred to `to`.
     *  - When `from` is zero, `tokenId` will be minted to `to`.
     *  - When `to` is zero, ``from``'s `tokenId` will be burned.
     *  - `from` and `to` are never zero at the same time.
     *
     *  To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     * @param from Address from which the token is being transferred
     * @param to Address to which the token is being transferred
     * @param tokenId ID of the token being transferred
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {}

    /**
     * @notice Hook that is called after any transfer of tokens. This includes minting and burning.
     * @dev Calling conditions:
     *
     *  - When `from` and `to` are both non-zero.
     *  - `from` and `to` are never zero at the same time.
     *
     *  To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     * @param from Address from which the token has been transferred
     * @param to Address to which the token has been transferred
     * @param tokenId ID of the token that has been transferred
     */
    function _afterTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {}

    /**
     * @notice Hook that is called before nested token transfer.
     * @dev To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     * @param from Address from which the token is being transferred
     * @param to Address to which the token is being transferred
     * @param fromTokenId ID of the token from which the given token is being transferred
     * @param toTokenId ID of the token to which the given token is being transferred
     * @param tokenId ID of the token being transferred
     * @param data Additional data with no specified format, sent in the addChild call
     */
    function _beforeNestedTokenTransfer(
        address from,
        address to,
        uint256 fromTokenId,
        uint256 toTokenId,
        uint256 tokenId,
        bytes memory data
    ) internal virtual {}

    /**
     * @notice Hook that is called after nested token transfer.
     * @dev To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     * @param from Address from which the token was transferred
     * @param to Address to which the token was transferred
     * @param fromTokenId ID of the token from which the given token was transferred
     * @param toTokenId ID of the token to which the given token was transferred
     * @param tokenId ID of the token that was transferred
     * @param data Additional data with no specified format, sent in the addChild call
     */
    function _afterNestedTokenTransfer(
        address from,
        address to,
        uint256 fromTokenId,
        uint256 toTokenId,
        uint256 tokenId,
        bytes memory data
    ) internal virtual {}

    /**
     * @notice Hook that is called before a child is added to the pending tokens array of a given token.
     * @dev The Child struct consists of the following values:
     *  [
     *      tokenId,
     *      contractAddress
     *  ]
     * @dev To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     * @param tokenId ID of the token that will receive a new pending child token
     * @param childAddress Address of the collection smart contract of the child token expected to be located at the
     *  specified index of the given parent token's pending children array
     * @param childId ID of the child token expected to be located at the specified index of the given parent token's
     *  pending children array
     * @param data Additional data with no specified format
     */
    function _beforeAddChild(
        uint256 tokenId,
        address childAddress,
        uint256 childId,
        bytes memory data
    ) internal virtual {}

    /**
     * @notice Hook that is called after a child is added to the pending tokens array of a given token.
     * @dev The Child struct consists of the following values:
     *  [
     *      tokenId,
     *      contractAddress
     *  ]
     * @dev To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     * @param tokenId ID of the token that has received a new pending child token
     * @param childAddress Address of the collection smart contract of the child token expected to be located at the
     *  specified index of the given parent token's pending children array
     * @param childId ID of the child token expected to be located at the specified index of the given parent token's
     *  pending children array
     * @param data Additional data with no specified format
     */
    function _afterAddChild(
        uint256 tokenId,
        address childAddress,
        uint256 childId,
        bytes memory data
    ) internal virtual {}

    /**
     * @notice Hook that is called before a child is accepted to the active tokens array of a given token.
     * @dev The Child struct consists of the following values:
     *  [
     *      tokenId,
     *      contractAddress
     *  ]
     * @dev To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     * @param parentId ID of the token that will accept a pending child token
     * @param childIndex Index of the child token to accept in the given parent token's pending children array
     * @param childAddress Address of the collection smart contract of the child token expected to be located at the
     *  specified index of the given parent token's pending children array
     * @param childId ID of the child token expected to be located at the specified index of the given parent token's
     *  pending children array
     */
    function _beforeAcceptChild(
        uint256 parentId,
        uint256 childIndex,
        address childAddress,
        uint256 childId
    ) internal virtual {}

    /**
     * @notice Hook that is called after a child is accepted to the active tokens array of a given token.
     * @dev The Child struct consists of the following values:
     *  [
     *      tokenId,
     *      contractAddress
     *  ]
     * @dev To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     * @param parentId ID of the token that has accepted a pending child token
     * @param childIndex Index of the child token that was accpeted in the given parent token's pending children array
     * @param childAddress Address of the collection smart contract of the child token that was expected to be located
     *  at the specified index of the given parent token's pending children array
     * @param childId ID of the child token that was expected to be located at the specified index of the given parent
     *  token's pending children array
     */
    function _afterAcceptChild(
        uint256 parentId,
        uint256 childIndex,
        address childAddress,
        uint256 childId
    ) internal virtual {}

    /**
     * @notice Hook that is called before a child is transferred from a given child token array of a given token.
     * @dev The Child struct consists of the following values:
     *  [
     *      tokenId,
     *      contractAddress
     *  ]
     * @dev To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     * @param tokenId ID of the token that will transfer a child token
     * @param childIndex Index of the child token that will be transferred from the given parent token's children array
     * @param childAddress Address of the collection smart contract of the child token that is expected to be located
     *  at the specified index of the given parent token's children array
     * @param childId ID of the child token that is expected to be located at the specified index of the given parent
     *  token's children array
     * @param isPending A boolean value signifying whether the child token is being transferred from the pending child
     *  tokens array (`true`) or from the active child tokens array (`false`)
     * @param data Additional data with no specified format, sent in the addChild call
     */
    function _beforeTransferChild(
        uint256 tokenId,
        uint256 childIndex,
        address childAddress,
        uint256 childId,
        bool isPending,
        bytes memory data
    ) internal virtual {}

    /**
     * @notice Hook that is called after a child is transferred from a given child token array of a given token.
     * @dev The Child struct consists of the following values:
     *  [
     *      tokenId,
     *      contractAddress
     *  ]
     * @dev To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     * @param tokenId ID of the token that has transferred a child token
     * @param childIndex Index of the child token that was transferred from the given parent token's children array
     * @param childAddress Address of the collection smart contract of the child token that was expected to be located
     *  at the specified index of the given parent token's children array
     * @param childId ID of the child token that was expected to be located at the specified index of the given parent
     *  token's children array
     * @param isPending A boolean value signifying whether the child token was transferred from the pending child tokens
     *  array (`true`) or from the active child tokens array (`false`)
     * @param data Additional data with no specified format, sent in the addChild call
     */
    function _afterTransferChild(
        uint256 tokenId,
        uint256 childIndex,
        address childAddress,
        uint256 childId,
        bool isPending,
        bytes memory data
    ) internal virtual {}

    /**
     * @notice Hook that is called before a pending child tokens array of a given token is cleared.
     * @dev To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     * @param tokenId ID of the token that will reject all of the pending child tokens
     */
    function _beforeRejectAllChildren(uint256 tokenId) internal virtual {}

    /**
     * @notice Hook that is called after a pending child tokens array of a given token is cleared.
     * @dev To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     * @param tokenId ID of the token that has rejected all of the pending child tokens
     */
    function _afterRejectAllChildren(uint256 tokenId) internal virtual {}

    // HELPERS

    /**
     * @notice Used to remove a specified child token form an array using its index within said array.
     * @dev The caller must ensure that the length of the array is valid compared to the index passed.
     * @dev The Child struct consists of the following values:
     *  [
     *      tokenId,
     *      contractAddress
     *  ]
     * @param array An array od Child struct containing info about the child tokens in a given child tokens array
     * @param index An index of the child token to remove in the accompanying array
     */
    function _removeChildByIndex(Child[] storage array, uint256 index) private {
        array[index] = array[array.length - 1];
        array.pop();
    }

    /// Mapping of uint64 Ids to asset metadata
    mapping(uint64 => string) internal _assets;

    /// Mapping of tokenId to new asset, to asset to be replaced
    mapping(uint256 => mapping(uint64 => uint64)) internal _assetReplacements;

    /// Mapping of tokenId to an array of active assets
    /// @dev Active recurses is unbounded, getting all would reach gas limit at around 30k items
    /// so we leave this as internal in case a custom implementation needs to implement pagination
    mapping(uint256 => uint64[]) internal _activeAssets;

    /// Mapping of tokenId to an array of pending assets
    mapping(uint256 => uint64[]) internal _pendingAssets;

    /// Mapping of tokenId to an array of priorities for active assets
    mapping(uint256 => uint64[]) internal _activeAssetPriorities;

    /// Mapping of tokenId to assetId to whether the token has this asset assigned
    mapping(uint256 => mapping(uint64 => bool)) internal _tokenAssets;

    /// Mapping from owner to operator approvals for assets
    mapping(address => mapping(address => bool))
        private _operatorApprovalsForAssets;

    /**
     * @inheritdoc IERC5773
     */
    function getAssetMetadata(
        uint256 tokenId,
        uint64 assetId
    ) public view virtual override returns (string memory metadata) {
        // Allow to get the asset metadata without a token having it:
        if (tokenId != 0 && !_tokenAssets[tokenId][assetId])
            revert RMRKTokenDoesNotHaveAsset();
        metadata = _assets[assetId];
    }

    /**
     * @inheritdoc IERC5773
     */
    function getActiveAssets(
        uint256 tokenId
    ) public view virtual returns (uint64[] memory assetIds) {
        assetIds = _activeAssets[tokenId];
    }

    /**
     * @inheritdoc IERC5773
     */
    function getPendingAssets(
        uint256 tokenId
    ) public view virtual returns (uint64[] memory assetIds) {
        assetIds = _pendingAssets[tokenId];
    }

    /**
     * @inheritdoc IERC5773
     */
    function getActiveAssetPriorities(
        uint256 tokenId
    ) public view virtual returns (uint64[] memory priorities) {
        priorities = _activeAssetPriorities[tokenId];
    }

    /**
     * @inheritdoc IERC5773
     */
    function getAssetReplacements(
        uint256 tokenId,
        uint64 newAssetId
    ) public view virtual returns (uint64 replacedAssetId) {
        replacedAssetId = _assetReplacements[tokenId][newAssetId];
    }

    /**
     * @inheritdoc IERC5773
     */
    function isApprovedForAllForAssets(
        address owner,
        address operator
    ) public view virtual returns (bool isApproved) {
        isApproved = _operatorApprovalsForAssets[owner][operator];
    }

    /**
     * @inheritdoc IERC5773
     */
    function setApprovalForAllForAssets(
        address operator,
        bool approved
    ) public virtual {
        if (_msgSender() == operator)
            revert RMRKApprovalForAssetsToCurrentOwner();

        _operatorApprovalsForAssets[_msgSender()][operator] = approved;
        emit ApprovalForAllForAssets(_msgSender(), operator, approved);
    }

    /**
     * @notice Used to validate the index on the pending assets array
     * @dev The call is reverted if the index is out of range or the asset Id is not present at the index.
     * @param tokenId ID of the token that the asset is validated from
     * @param index Index of the asset in the pending array
     * @param assetId Id of the asset expected to be in the index
     */
    function _validatePendingAssetAtIndex(
        uint256 tokenId,
        uint256 index,
        uint64 assetId
    ) private view {
        if (index >= _pendingAssets[tokenId].length)
            revert RMRKIndexOutOfRange();
        if (assetId != _pendingAssets[tokenId][index])
            revert RMRKUnexpectedAssetId();
    }

    /**
     * @notice Used to remove the asset at the index on the pending assets array
     * @param tokenId ID of the token that the asset is being removed from
     * @param index Index of the asset in the pending array
     * @param assetId Id of the asset expected to be in the index
     */
    function _removePendingAsset(
        uint256 tokenId,
        uint256 index,
        uint64 assetId
    ) private {
        _pendingAssets[tokenId].removeItemByIndex(index);
        delete _assetReplacements[tokenId][assetId];
    }

    /**
     * @notice Used to add an asset entry.
     * @dev If the specified ID is already used by another asset, the execution will be reverted.
     * @dev This internal function warrants custom access control to be implemented when used.
     * @dev Emits ***AssetSet*** event.
     * @param id ID of the asset to assign to the new asset
     * @param metadataURI Metadata URI of the asset
     */
    function _addAssetEntry(
        uint64 id,
        string memory metadataURI
    ) internal virtual {
        if (id == uint64(0)) revert RMRKIdZeroForbidden();
        if (bytes(_assets[id]).length > 0) revert RMRKAssetAlreadyExists();

        _beforeAddAsset(id, metadataURI);
        _assets[id] = metadataURI;

        emit AssetSet(id);
        _afterAddAsset(id, metadataURI);
    }

    /**
     * @notice Used to add an asset to a token.
     * @dev If the given asset is already added to the token, the execution will be reverted.
     * @dev If the asset ID is invalid, the execution will be reverted.
     * @dev If the token already has the maximum amount of pending assets (128), the execution will be
     *  reverted.
     * @dev Emits ***AssetAddedToTokens*** event.
     * @param tokenId ID of the token to add the asset to
     * @param assetId ID of the asset to add to the token
     * @param replacesAssetWithId ID of the asset to replace from the token's list of active assets
     */
    function _addAssetToToken(
        uint256 tokenId,
        uint64 assetId,
        uint64 replacesAssetWithId
    ) internal virtual {
        if (_tokenAssets[tokenId][assetId]) revert RMRKAssetAlreadyExists();

        if (bytes(_assets[assetId]).length == uint256(0))
            revert RMRKNoAssetMatchingId();

        if (_pendingAssets[tokenId].length >= 128)
            revert RMRKMaxPendingAssetsReached();

        _beforeAddAssetToToken(tokenId, assetId, replacesAssetWithId);
        _tokenAssets[tokenId][assetId] = true;
        _pendingAssets[tokenId].push(assetId);

        if (replacesAssetWithId != uint64(0)) {
            _assetReplacements[tokenId][assetId] = replacesAssetWithId;
        }

        uint256[] memory tokenIds = new uint256[](1);
        tokenIds[0] = tokenId;
        emit AssetAddedToTokens(tokenIds, assetId, replacesAssetWithId);
        _afterAddAssetToToken(tokenId, assetId, replacesAssetWithId);
    }

    /**
     * @notice Hook that is called before an asset is added.
     * @param id ID of the asset
     * @param metadataURI Metadata URI of the asset
     */
    function _beforeAddAsset(
        uint64 id,
        string memory metadataURI
    ) internal virtual {}

    /**
     * @notice Hook that is called after an asset is added.
     * @param id ID of the asset
     * @param metadataURI Metadata URI of the asset
     */
    function _afterAddAsset(
        uint64 id,
        string memory metadataURI
    ) internal virtual {}

    /**
     * @notice Hook that is called before adding an asset to a token's pending assets array.
     * @dev If the asset doesn't intend to replace another asset, the `replacesAssetWithId` value should be `0`.
     * @param tokenId ID of the token to which the asset is being added
     * @param assetId ID of the asset that is being added
     * @param replacesAssetWithId ID of the asset that this asset is attempting to replace
     */
    function _beforeAddAssetToToken(
        uint256 tokenId,
        uint64 assetId,
        uint64 replacesAssetWithId
    ) internal virtual {}

    /**
     * @notice Hook that is called after an asset has been added to a token's pending assets array.
     * @dev If the asset doesn't intend to replace another asset, the `replacesAssetWithId` value should be `0`.
     * @param tokenId ID of the token to which the asset is has been added
     * @param assetId ID of the asset that is has been added
     * @param replacesAssetWithId ID of the asset that this asset is attempting to replace
     */
    function _afterAddAssetToToken(
        uint256 tokenId,
        uint64 assetId,
        uint64 replacesAssetWithId
    ) internal virtual {}

    /**
     * @notice Hook that is called before an asset is accepted to a token's active assets array.
     * @param tokenId ID of the token for which the asset is being accepted
     * @param index Index of the asset in the token's pending assets array
     * @param assetId ID of the asset expected to be located at the specified `index`
     */
    function _beforeAcceptAsset(
        uint256 tokenId,
        uint256 index,
        uint64 assetId
    ) internal virtual {}

    /**
     * @notice Hook that is called after an asset is accepted to a token's active assets array.
     * @param tokenId ID of the token for which the asset has been accepted
     * @param index Index of the asset in the token's pending assets array
     * @param assetId ID of the asset expected to have been located at the specified `index`
     * @param replacedAssetId ID of the asset that has been replaced by the accepted asset
     */
    function _afterAcceptAsset(
        uint256 tokenId,
        uint256 index,
        uint64 assetId,
        uint64 replacedAssetId
    ) internal virtual {}

    /**
     * @notice Hook that is called before rejecting an asset.
     * @param tokenId ID of the token from which the asset is being rejected
     * @param index Index of the asset in the token's pending assets array
     * @param assetId ID of the asset expected to be located at the specified `index`
     */
    function _beforeRejectAsset(
        uint256 tokenId,
        uint256 index,
        uint64 assetId
    ) internal virtual {}

    /**
     * @notice Hook that is called after rejecting an asset.
     * @param tokenId ID of the token from which the asset has been rejected
     * @param index Index of the asset in the token's pending assets array
     * @param assetId ID of the asset expected to have been located at the specified `index`
     */
    function _afterRejectAsset(
        uint256 tokenId,
        uint256 index,
        uint64 assetId
    ) internal virtual {}

    /**
     * @notice Hook that is called before rejecting all assets of a token.
     * @param tokenId ID of the token from which all of the assets are being rejected
     */
    function _beforeRejectAllAssets(uint256 tokenId) internal virtual {}

    /**
     * @notice Hook that is called after rejecting all assets of a token.
     * @param tokenId ID of the token from which all of the assets have been rejected
     */
    function _afterRejectAllAssets(uint256 tokenId) internal virtual {}

    /**
     * @notice Hook that is called before the priorities for token's assets is set.
     * @param tokenId ID of the token for which the asset priorities are being set
     * @param priorities[] An array of priorities for token's active resources
     */
    function _beforeSetPriority(
        uint256 tokenId,
        uint64[] memory priorities
    ) internal virtual {}

    /**
     * @notice Hook that is called after the priorities for token's assets is set.
     * @param tokenId ID of the token for which the asset priorities have been set
     * @param priorities[] An array of priorities for token's active resources
     */
    function _afterSetPriority(
        uint256 tokenId,
        uint64[] memory priorities
    ) internal virtual {}

    // ------------------- ASSETS --------------

    // ------------------- ASSET APPROVALS --------------

    /**
     * @notice Mapping from token ID to approver address to approved address for assets.
     * @dev The approver is necessary so approvals are invalidated for nested children on transfer.
     * @dev WARNING: If a child NFT returns the original root owner, old permissions would be active again.
     */
    mapping(uint256 => mapping(address => address))
        private _tokenApprovalsForAssets;

    // ------------------- EQUIPPABLE --------------
    /// Mapping of uint64 asset ID to corresponding catalog address.
    mapping(uint64 => address) internal _catalogAddresses;
    /// Mapping of uint64 ID to asset object.
    mapping(uint64 => uint64) internal _equippableGroupIds;
    /// Mapping of assetId to catalog parts applicable to this asset, both fixed and slot
    mapping(uint64 => uint64[]) internal _partIds;

    /// Mapping of token ID to catalog address to slot part ID to equipment information. Used to compose an NFT.
    mapping(uint256 => mapping(address => mapping(uint64 => Equipment)))
        internal _equipments;

    /// Mapping of token ID to child (nestable) address to child ID to count of equipped items. Used to check if equipped.
    mapping(uint256 => mapping(address => mapping(uint256 => uint256)))
        internal _equipCountPerChild;

    /// Mapping of `equippableGroupId` to parent contract address and valid `slotId`.
    mapping(uint64 => mapping(address => uint64)) internal _validParentSlots;

    /**
     * @notice Used to verify that the caller is either the owner of the given token or approved to manage the token's assets
     *  of the owner.
     * @param tokenId ID of the token that we are checking
     */
    function _onlyApprovedForAssetsOrOwner(uint256 tokenId) internal view {
        address owner = ownerOf(tokenId);
        if (
            !(_msgSender() == owner ||
                isApprovedForAllForAssets(owner, _msgSender()) ||
                getApprovedForAssets(tokenId) == _msgSender())
        ) revert RMRKNotApprovedForAssetsOrOwner();
    }

    /**
     * @notice Used to ensure that the caller is either the owner of the given token or approved to manage the token's assets
     *  of the owner.
     * @dev If that is not the case, the execution of the function will be reverted.
     * @param tokenId ID of the token that we are checking
     */
    modifier onlyApprovedForAssetsOrOwner(uint256 tokenId) {
        _onlyApprovedForAssetsOrOwner(tokenId);
        _;
    }

    /**
     * @inheritdoc IERC165
     */
    function supportsInterface(
        bytes4 interfaceId
    ) public view virtual override returns (bool) {
        return
            interfaceId == type(IERC165).interfaceId ||
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC7401).interfaceId ||
            interfaceId == type(IERC5773).interfaceId ||
            interfaceId == type(IERC6220).interfaceId;
    }

    // ------------------------------- ASSETS ------------------------------

    // --------------------------- ASSET HANDLERS -------------------------

    /**
     * @notice Accepts a asset at from the pending array of given token.
     * @dev Migrates the asset from the token's pending asset array to the token's active asset array.
     * @dev Active assets cannot be removed by anyone, but can be replaced by a new asset.
     * @dev Requirements:
     *
     *  - The caller must own the token or be approved to manage the token's assets
     *  - `tokenId` must exist.
     *  - `index` must be in range of the length of the pending asset array.
     * @dev Emits an {AssetAccepted} event.
     * @param tokenId ID of the token for which to accept the pending asset
     * @param index Index of the asset in the pending array to accept
     * @param assetId ID of the asset that is being accepted
     */
    function acceptAsset(
        uint256 tokenId,
        uint256 index,
        uint64 assetId
    ) public virtual onlyApprovedForAssetsOrOwner(tokenId) {
        _acceptAsset(tokenId, index, assetId);
    }

    /**
     * @notice Used to accept a pending asset.
     * @dev The call is reverted if there is no pending asset at a given index.
     * @dev Emits ***AssetAccepted*** event.
     * @param tokenId ID of the token for which to accept the pending asset
     * @param index Index of the asset in the pending array to accept
     * @param assetId ID of the asset to accept in token's pending array
     */
    function _acceptAsset(
        uint256 tokenId,
        uint256 index,
        uint64 assetId
    ) internal virtual {
        _validatePendingAssetAtIndex(tokenId, index, assetId);
        _beforeAcceptAsset(tokenId, index, assetId);

        uint64 replacesId = _assetReplacements[tokenId][assetId];
        uint256 replaceIndex;
        bool replacefound;
        if (replacesId != uint64(0))
            (replaceIndex, replacefound) = _activeAssets[tokenId].indexOf(
                replacesId
            );

        if (replacefound) {
            // We don't want to remove and then push a new asset.
            // This way we also keep the priority of the original asset
            _activeAssets[tokenId][replaceIndex] = assetId;
            delete _tokenAssets[tokenId][replacesId];
        } else {
            // We use the current size as next priority, by default priorities would be [0,1,2...]
            _activeAssetPriorities[tokenId].push(
                uint64(_activeAssets[tokenId].length)
            );
            _activeAssets[tokenId].push(assetId);
            replacesId = uint64(0);
        }
        _removePendingAsset(tokenId, index, assetId);

        emit AssetAccepted(tokenId, assetId, replacesId);
        _afterAcceptAsset(tokenId, index, assetId, replacesId);
    }

    /**
     * @notice Rejects a asset from the pending array of given token.
     * @dev Removes the asset from the token's pending asset array.
     * @dev Requirements:
     *
     *  - The caller must own the token or be approved to manage the token's assets
     *  - `tokenId` must exist.
     *  - `index` must be in range of the length of the pending asset array.
     * @dev Emits a {AssetRejected} event.
     * @param tokenId ID of the token that the asset is being rejected from
     * @param index Index of the asset in the pending array to be rejected
     * @param assetId ID of the asset that is being rejected
     */
    function rejectAsset(
        uint256 tokenId,
        uint256 index,
        uint64 assetId
    ) public virtual onlyApprovedForAssetsOrOwner(tokenId) {
        _validatePendingAssetAtIndex(tokenId, index, assetId);
        _beforeRejectAsset(tokenId, index, assetId);

        _removePendingAsset(tokenId, index, assetId);
        delete _tokenAssets[tokenId][assetId];

        emit AssetRejected(tokenId, assetId);
        _afterRejectAsset(tokenId, index, assetId);
    }

    /**
     * @notice Rejects all assets from the pending array of a given token.
     * @dev Effecitvely deletes the pending array.
     * @dev Requirements:
     *
     *  - The caller must own the token or be approved to manage the token's assets
     *  - `tokenId` must exist.
     * @dev Emits a {AssetRejected} event with assetId = 0.
     * @param tokenId ID of the token of which to clear the pending array.
     * @param maxRejections Maximum number of expected assets to reject, used to prevent from rejecting assets which
     *  arrive just before this operation.
     */
    function rejectAllAssets(
        uint256 tokenId,
        uint256 maxRejections
    ) public virtual onlyApprovedForAssetsOrOwner(tokenId) {
        uint256 len = _pendingAssets[tokenId].length;
        if (len > maxRejections) revert RMRKUnexpectedNumberOfAssets();

        _beforeRejectAllAssets(tokenId);

        for (uint256 i; i < len; ) {
            uint64 assetId = _pendingAssets[tokenId][i];
            delete _assetReplacements[tokenId][assetId];
            unchecked {
                ++i;
            }
        }
        delete (_pendingAssets[tokenId]);

        emit AssetRejected(tokenId, uint64(0));
        _afterRejectAllAssets(tokenId);
    }

    /**
     * @notice Sets a new priority array for a given token.
     * @dev The priority array is a non-sequential list of `uint64`s, where the lowest value is considered highest
     *  priority.
     * @dev Value `0` of a priority is a special case equivalent to unitialized.
     * @dev Requirements:
     *
     *  - The caller must own the token or be approved to manage the token's assets
     *  - `tokenId` must exist.
     *  - The length of `priorities` must be equal the length of the active assets array.
     * @dev Emits a {AssetPrioritySet} event.
     * @param tokenId ID of the token to set the priorities for
     * @param priorities An array of priority values
     */
    function setPriority(
        uint256 tokenId,
        uint64[] memory priorities
    ) public virtual onlyApprovedForAssetsOrOwner(tokenId) {
        uint256 length = priorities.length;
        if (length != _activeAssets[tokenId].length)
            revert RMRKBadPriorityListLength();

        _beforeSetPriority(tokenId, priorities);
        _activeAssetPriorities[tokenId] = priorities;

        emit AssetPrioritySet(tokenId);
        _afterSetPriority(tokenId, priorities);
    }

    // --------------------------- ASSET INTERNALS -------------------------

    /**
     * @notice Used to add a asset entry.
     * @dev This internal function warrants custom access control to be implemented when used.
     * @param id ID of the asset being added
     * @param equippableGroupId ID of the equippable group being marked as equippable into the slot associated with
     *  `Parts` of the `Slot` type
     * @param catalogAddress Address of the `Catalog` associated with the asset
     * @param metadataURI The metadata URI of the asset
     * @param partIds An array of IDs of fixed and slot parts to be included in the asset
     */
    function _addAssetEntry(
        uint64 id,
        uint64 equippableGroupId,
        address catalogAddress,
        string memory metadataURI,
        uint64[] memory partIds
    ) internal virtual {
        _addAssetEntry(id, metadataURI);

        if (catalogAddress == address(0) && partIds.length != 0)
            revert RMRKCatalogRequiredForParts();

        _catalogAddresses[id] = catalogAddress;
        _equippableGroupIds[id] = equippableGroupId;
        _partIds[id] = partIds;
    }

    // ----------------------- ASSET APPROVALS ------------------------

    /**
     * @notice Used to grant approvals for specific tokens to a specified address.
     * @dev This can only be called by the owner of the token or by an account that has been granted permission to
     *  manage all of the owner's assets.
     * @param to Address of the account to receive the approval to the specified token
     * @param tokenId ID of the token for which we are granting the permission
     */
    function approveForAssets(address to, uint256 tokenId) public virtual {
        address owner = ownerOf(tokenId);
        if (to == owner) revert RMRKApprovalForAssetsToCurrentOwner();

        if (
            _msgSender() != owner &&
            !isApprovedForAllForAssets(owner, _msgSender())
        ) revert RMRKApproveForAssetsCallerIsNotOwnerNorApprovedForAll();
        _approveForAssets(to, tokenId);
    }

    /**
     * @notice Used to get the address of the user that is approved to manage the specified token from the current
     *  owner.
     * @param tokenId ID of the token we are checking
     * @return approved Address of the account that is approved to manage the token
     */
    function getApprovedForAssets(
        uint256 tokenId
    ) public view virtual returns (address approved) {
        _requireMinted(tokenId);
        approved = _tokenApprovalsForAssets[tokenId][ownerOf(tokenId)];
    }

    /**
     * @notice Internal function for granting approvals for a specific token.
     * @param to Address of the account we are granting an approval to
     * @param tokenId ID of the token we are granting the approval for
     */
    function _approveForAssets(address to, uint256 tokenId) internal virtual {
        address owner = ownerOf(tokenId);
        _tokenApprovalsForAssets[tokenId][owner] = to;
        emit ApprovalForAssets(owner, to, tokenId);
    }

    // ------------------------------- EQUIPPING ------------------------------

    /**
     * @inheritdoc IERC6220
     */
    function equip(
        IntakeEquip memory data
    ) public virtual onlyApprovedForAssetsOrOwner(data.tokenId) nonReentrant {
        address catalogAddress = _catalogAddresses[data.assetId];
        uint64 slotPartId = data.slotPartId;
        if (
            _equipments[data.tokenId][catalogAddress][slotPartId]
                .childEquippableAddress != address(0)
        ) revert RMRKSlotAlreadyUsed();

        // Check from parent's asset perspective:
        _checkAssetAcceptsSlot(data.assetId, slotPartId);

        IERC7401.Child memory child = childOf(data.tokenId, data.childIndex);

        // Check from child perspective intention to be used in part
        // We add reentrancy guard because of this call, it happens before updating state
        if (
            !IERC6220(child.contractAddress)
                .canTokenBeEquippedWithAssetIntoSlot(
                    address(this),
                    child.tokenId,
                    data.childAssetId,
                    slotPartId
                )
        ) revert RMRKTokenCannotBeEquippedWithAssetIntoSlot();

        // Check from catalog perspective
        if (
            !IRMRKCatalog(catalogAddress).checkIsEquippable(
                slotPartId,
                child.contractAddress
            )
        ) revert RMRKEquippableEquipNotAllowedByCatalog();

        _beforeEquip(data);
        Equipment memory newEquip = Equipment({
            assetId: data.assetId,
            childAssetId: data.childAssetId,
            childId: child.tokenId,
            childEquippableAddress: child.contractAddress
        });

        _equipments[data.tokenId][catalogAddress][slotPartId] = newEquip;
        _equipCountPerChild[data.tokenId][child.contractAddress][
            child.tokenId
        ] += 1;

        emit ChildAssetEquipped(
            data.tokenId,
            data.assetId,
            slotPartId,
            child.tokenId,
            child.contractAddress,
            data.childAssetId
        );
        _afterEquip(data);
    }

    /**
     * @notice Private function to check if a given asset accepts a given slot or not.
     * @dev Execution will be reverted if the `Slot` does not apply for the asset.
     * @param assetId ID of the asset
     * @param slotPartId ID of the `Slot`
     */
    function _checkAssetAcceptsSlot(
        uint64 assetId,
        uint64 slotPartId
    ) private view {
        (, bool found) = _partIds[assetId].indexOf(slotPartId);
        if (!found) revert RMRKTargetAssetCannotReceiveSlot();
    }

    /**
     * @inheritdoc IERC6220
     */
    function unequip(
        uint256 tokenId,
        uint64 assetId,
        uint64 slotPartId
    ) public virtual onlyApprovedForAssetsOrOwner(tokenId) {
        address targetCatalogAddress = _catalogAddresses[assetId];
        Equipment memory equipment = _equipments[tokenId][targetCatalogAddress][
            slotPartId
        ];
        if (equipment.childEquippableAddress == address(0))
            revert RMRKNotEquipped();
        _beforeUnequip(tokenId, assetId, slotPartId);

        delete _equipments[tokenId][targetCatalogAddress][slotPartId];
        _equipCountPerChild[tokenId][equipment.childEquippableAddress][
            equipment.childId
        ] -= 1;

        emit ChildAssetUnequipped(
            tokenId,
            assetId,
            slotPartId,
            equipment.childId,
            equipment.childEquippableAddress,
            equipment.childAssetId
        );
        _afterUnequip(tokenId, assetId, slotPartId);
    }

    /**
     * @inheritdoc IERC6220
     */
    function isChildEquipped(
        uint256 tokenId,
        address childAddress,
        uint256 childId
    ) public view virtual returns (bool isEquipped) {
        isEquipped = _equipCountPerChild[tokenId][childAddress][childId] != 0;
    }

    // --------------------- ADMIN VALIDATION ---------------------

    /**
     * @notice Internal function used to declare that the assets belonging to a given `equippableGroupId` are
     *  equippable into the `Slot` associated with the `partId` of the collection at the specified `parentAddress`.
     * @dev Emits ***ValidParentEquippableGroupIdSet*** event.
     * @param equippableGroupId ID of the equippable group
     * @param parentAddress Address of the parent into which the equippable group can be equipped into
     * @param slotPartId ID of the `Slot` that the items belonging to the equippable group can be equipped into
     */
    function _setValidParentForEquippableGroup(
        uint64 equippableGroupId,
        address parentAddress,
        uint64 slotPartId
    ) internal virtual {
        if (equippableGroupId == uint64(0) || slotPartId == uint64(0))
            revert RMRKIdZeroForbidden();
        _validParentSlots[equippableGroupId][parentAddress] = slotPartId;
        emit ValidParentEquippableGroupIdSet(
            equippableGroupId,
            slotPartId,
            parentAddress
        );
    }

    /**
     * @inheritdoc IERC6220
     */
    function canTokenBeEquippedWithAssetIntoSlot(
        address parent,
        uint256 tokenId,
        uint64 assetId,
        uint64 slotId
    ) public view virtual returns (bool canBeEquipped) {
        uint64 equippableGroupId = _equippableGroupIds[assetId];
        uint64 equippableSlot = _validParentSlots[equippableGroupId][parent];
        if (equippableSlot == slotId) {
            (, bool found) = getActiveAssets(tokenId).indexOf(assetId);
            canBeEquipped = found;
        }
    }

    // --------------------- Getting Extended Assets ---------------------

    /**
     * @inheritdoc IERC6220
     */
    function getAssetAndEquippableData(
        uint256 tokenId,
        uint64 assetId
    )
        public
        view
        virtual
        returns (
            string memory metadataURI,
            uint64 equippableGroupId,
            address catalogAddress,
            uint64[] memory partIds
        )
    {
        metadataURI = getAssetMetadata(tokenId, assetId);
        equippableGroupId = _equippableGroupIds[assetId];
        catalogAddress = _catalogAddresses[assetId];
        partIds = _partIds[assetId];
    }

    ////////////////////////////////////////
    //              UTILS
    ////////////////////////////////////////

    /**
     * @inheritdoc IERC6220
     */
    function getEquipment(
        uint256 tokenId,
        address targetCatalogAddress,
        uint64 slotPartId
    ) public view virtual returns (Equipment memory equipment) {
        equipment = _equipments[tokenId][targetCatalogAddress][slotPartId];
    }

    /**
     * @notice Checks the destination is valid for a Nest Transfer/Mint.
     * @dev The destination must be a contract that implements the IERC7401 interface.
     * @param to Address of the destination
     */
    function _checkDestination(address to) internal view {
        // Checking if it is a contract before calling it seems redundant, but otherwise it would revert with no error
        if (to.code.length == 0) revert RMRKIsNotContract();
        if (!IERC165(to).supportsInterface(type(IERC7401).interfaceId))
            revert RMRKNestableTransferToNonRMRKNestableImplementer();
    }

    // HOOKS

    /**
     * @notice A hook to be called before a equipping a asset to the token.
     * @dev The `IntakeEquip` struct consist of the following data:
     *  [
     *      tokenId,
     *      childIndex,
     *      assetId,
     *      slotPartId,
     *      childAssetId
     *  ]
     * @param data The `IntakeEquip` struct containing data of the asset that is being equipped
     */
    function _beforeEquip(IntakeEquip memory data) internal virtual {}

    /**
     * @notice A hook to be called after equipping a asset to the token.
     * @dev The `IntakeEquip` struct consist of the following data:
     *  [
     *      tokenId,
     *      childIndex,
     *      assetId,
     *      slotPartId,
     *      childAssetId
     *  ]
     * @param data The `IntakeEquip` struct containing data of the asset that was equipped
     */
    function _afterEquip(IntakeEquip memory data) internal virtual {}

    /**
     * @notice A hook to be called before unequipping a asset from the token.
     * @param tokenId ID of the token from which the asset is being unequipped
     * @param assetId ID of the asset being unequipped
     * @param slotPartId ID of the slot from which the asset is being unequipped
     */
    function _beforeUnequip(
        uint256 tokenId,
        uint64 assetId,
        uint64 slotPartId
    ) internal virtual {}

    /**
     * @notice A hook to be called after unequipping a asset from the token.
     * @param tokenId ID of the token from which the asset was unequipped
     * @param assetId ID of the asset that was unequipped
     * @param slotPartId ID of the slot from which the asset was unequipped
     */
    function _afterUnequip(
        uint256 tokenId,
        uint64 assetId,
        uint64 slotPartId
    ) internal virtual {}
}

// SPDX-License-Identifier: Apache-2.0

pragma solidity ^0.8.21;

import {IERC2981} from "@openzeppelin/contracts/interfaces/IERC2981.sol";
import "../library/RMRKErrors.sol";

/**
 * @title RMRKRoyalties
 * @author RMRK team
 * @notice Smart contract of the RMRK Royalties module.
 */
abstract contract RMRKRoyalties {
    /** is IERC2981 **/ // Inheritance is commmnted to prevent linearization issues
    address private _royaltyRecipient;
    uint256 private _royaltyPercentageBps;

    /**
     * @notice Used to initiate the smart contract.
     * @dev `royaltyPercentageBps` is expressed in basis points, so 1 basis point equals 0.01% and 500 basis points
     *  equal 5%.
     * @param royaltyRecipient Address to which royalties should be sent
     * @param royaltyPercentageBps The royalty percentage expressed in basis points
     */
    constructor(address royaltyRecipient, uint256 royaltyPercentageBps) {
        _setRoyaltyRecipient(royaltyRecipient);
        if (royaltyPercentageBps >= 10000) revert RMRKRoyaltiesTooHigh();
        _royaltyPercentageBps = royaltyPercentageBps;
    }

    /**
     * @notice Used to update recipient of royalties.
     * @dev Custom access control has to be implemented to ensure that only the intended actors can update the
     *  beneficiary.
     * @param newRoyaltyRecipient Address of the new recipient of royalties
     */
    function updateRoyaltyRecipient(
        address newRoyaltyRecipient
    ) external virtual;

    /**
     * @notice Used to update the royalty recipient.
     * @param newRoyaltyRecipient Address of the new recipient of royalties
     */
    function _setRoyaltyRecipient(address newRoyaltyRecipient) internal {
        _royaltyRecipient = newRoyaltyRecipient;
    }

    /**
     * @notice Used to retrieve the recipient of royalties.
     * @return recipient Address of the recipient of royalties
     */
    function getRoyaltyRecipient()
        public
        view
        virtual
        returns (address recipient)
    {
        recipient = _royaltyRecipient;
    }

    /**
     * @notice Used to retrieve the specified royalty percentage.
     * @return royaltyPercentageBps The royalty percentage expressed in the basis points
     */
    function getRoyaltyPercentage()
        public
        view
        virtual
        returns (uint256 royaltyPercentageBps)
    {
        royaltyPercentageBps = _royaltyPercentageBps;
    }

    /**
     * @notice Used to retrieve the information about who shall receive royalties of a sale of the specified token and
     *  how much they will be.
     * @param tokenId ID of the token for which the royalty info is being retrieved
     * @param salePrice Price of the token sale
     * @return receiver The beneficiary receiving royalties of the sale
     * @return royaltyAmount The value of the royalties recieved by the `receiver` from the sale
     */
    function royaltyInfo(
        uint256 tokenId,
        uint256 salePrice
    ) external view virtual returns (address receiver, uint256 royaltyAmount) {
        uint256(tokenId); // Silence the warning about unused variable, needed for docs generation
        receiver = _royaltyRecipient;
        royaltyAmount = (salePrice * _royaltyPercentageBps) / 10000;
    }
}

// SPDX-License-Identifier: Apache-2.0

pragma solidity ^0.8.21;

import "./IERC7590.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

error InsufficientBalance();
error InvalidAddress();
error InvalidAmountTransferred();
error InvalidValue();

abstract contract RMRKTokenHolder is IERC7590 {
    mapping(uint256 tokenId => mapping(address erc20Address => uint256 balance))
        private _balances;
    mapping(uint256 tokenHolderId => uint256 nonce)
        private _erc20TransferOutNonce;

    /**
     * @inheritdoc IERC7590
     */
    function balanceOfERC20(
        address erc20Contract,
        uint256 tokenId
    ) public view returns (uint256) {
        return _balances[tokenId][erc20Contract];
    }

    /**
     * @notice Transfer ERC-20 tokens from a specific token
     * @dev The balance MUST be transferred from this smart contract.
     * @dev Implementers should validate that the `msg.sender` is either the token owner or approved to manage it before calling this.
     * @param erc20Contract The ERC-20 contract
     * @param tokenId The token to transfer from
     * @param amount The number of ERC-20 tokens to transfer
     * @param data Additional data with no specified format, to allow for custom logic
     */
    function _transferHeldERC20FromToken(
        address erc20Contract,
        uint256 tokenId,
        address to,
        uint256 amount,
        bytes memory data
    ) internal {
        if (amount == 0) {
            revert InvalidValue();
        }
        if (to == address(0) || erc20Contract == address(0)) {
            revert InvalidAddress();
        }
        if (_balances[tokenId][erc20Contract] < amount) {
            revert InsufficientBalance();
        }
        _beforeTransferHeldERC20FromToken(
            erc20Contract,
            tokenId,
            to,
            amount,
            data
        );
        IERC20 erc20 = IERC20(erc20Contract);
        uint256 initBalance = erc20.balanceOf(address(this));
        _balances[tokenId][erc20Contract] -= amount;
        _erc20TransferOutNonce[tokenId]++;

        erc20.transfer(to, amount);
        uint256 newBalance = erc20.balanceOf(address(this));
        // Since a token transfer could be taxed (i.e. part of the value is taken by a 3rd party), we need to check the actual amount transferred. It is up to the implementer to either revert if the difference differs from the `amount` parameter or use the actual amount transferred instead of the `amount` parameter. We revert.
        if (newBalance + amount != initBalance) {
            revert InvalidAmountTransferred();
        }

        emit TransferredERC20(erc20Contract, tokenId, to, amount);
        _afterTransferHeldERC20FromToken(
            erc20Contract,
            tokenId,
            to,
            amount,
            data
        );
    }

    /**
     * @inheritdoc IERC7590
     */
    function transferERC20ToToken(
        address erc20Contract,
        uint256 tokenId,
        uint256 amount,
        bytes memory data
    ) public {
        if (amount == 0) {
            revert InvalidValue();
        }
        if (erc20Contract == address(0)) {
            revert InvalidAddress();
        }
        _beforeTransferERC20ToToken(
            erc20Contract,
            tokenId,
            msg.sender,
            amount,
            data
        );
        IERC20 erc20 = IERC20(erc20Contract);
        uint256 initBalance = erc20.balanceOf(address(this));
        erc20.transferFrom(msg.sender, address(this), amount);
        uint256 newBalance = erc20.balanceOf(address(this));
        // Since a token transfer could be taxed (i.e. part of the value is taken by a 3rd party), we need to check the actual amount transferred. It is up to the implementer to either revert if the difference differs from the `amount` parameter or use the actual amount transferred instead of the `amount` parameter. We revert.
        if (initBalance + amount != newBalance) {
            revert InvalidAmountTransferred();
        }
        _balances[tokenId][erc20Contract] += amount;

        emit ReceivedERC20(erc20Contract, tokenId, msg.sender, amount);
        _afterTransferERC20ToToken(
            erc20Contract,
            tokenId,
            msg.sender,
            amount,
            data
        );
    }

    /**
     * @inheritdoc IERC7590
     */
    function erc20TransferOutNonce(
        uint256 tokenId
    ) public view returns (uint256) {
        return _erc20TransferOutNonce[tokenId];
    }

    /**
     * @notice Hook that is called before any transfer of ERC-20 tokens from a token
     * @param erc20Contract The ERC-20 contract
     * @param tokenId The token to transfer from
     * @param to The address to send the ERC-20 tokens to
     * @param amount The number of ERC-20 tokens to transfer
     * @param data Additional data with no specified format, to allow for custom logic
     */
    function _beforeTransferHeldERC20FromToken(
        address erc20Contract,
        uint256 tokenId,
        address to,
        uint256 amount,
        bytes memory data
    ) internal virtual {}

    /**
     * @notice Hook that is called after any transfer of ERC-20 tokens from a token
     * @param erc20Contract The ERC-20 contract
     * @param tokenId The token to transfer from
     * @param to The address to send the ERC-20 tokens to
     * @param amount The number of ERC-20 tokens to transfer
     * @param data Additional data with no specified format, to allow for custom logic
     */
    function _afterTransferHeldERC20FromToken(
        address erc20Contract,
        uint256 tokenId,
        address to,
        uint256 amount,
        bytes memory data
    ) internal virtual {}

    /**
     * @notice Hook that is called before any transfer of ERC-20 tokens to a token
     * @param erc20Contract The ERC-20 contract
     * @param tokenId The token to transfer from
     * @param from The address to send the ERC-20 tokens from
     * @param amount The number of ERC-20 tokens to transfer
     * @param data Additional data with no specified format, to allow for custom logic
     */
    function _beforeTransferERC20ToToken(
        address erc20Contract,
        uint256 tokenId,
        address from,
        uint256 amount,
        bytes memory data
    ) internal virtual {}

    /**
     * @notice Hook that is called after any transfer of ERC-20 tokens to a token
     * @param erc20Contract The ERC-20 contract
     * @param tokenId The token to transfer from
     * @param from The address to send the ERC-20 tokens from
     * @param amount The number of ERC-20 tokens to transfer
     * @param data Additional data with no specified format, to allow for custom logic
     */
    function _afterTransferERC20ToToken(
        address erc20Contract,
        uint256 tokenId,
        address from,
        uint256 amount,
        bytes memory data
    ) internal virtual {}

    function supportsInterface(
        bytes4 interfaceId
    ) public view virtual override returns (bool) {
        return type(IERC7590).interfaceId == interfaceId;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)

pragma solidity ^0.8.21;

error RentrantCall();

/**
 * @title ReentrancyGuard
 * @notice Smart contract used to guard against potential reentrancy exploits.
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    /**
     * @notice Initializes the ReentrancyGuard with the `_status` of `_NOT_ENTERED`.
     */
    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @notice Used to ensure that the function it is applied to cannot be reentered.
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _nonReentrantIn();
        _;
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }

    /**
     * @notice Used to ensure that the current call is not a reentrant call.
     * @dev If reentrant call is detected, the execution will be reverted.
     */
    function _nonReentrantIn() private {
        // On the first call to nonReentrant, _notEntered will be true
        if (_status == _ENTERED) revert RentrantCall();

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/math/SignedMath.sol)

pragma solidity ^0.8.20;

/**
 * @dev Standard signed math utilities missing in the Solidity language.
 */
library SignedMath {
    /**
     * @dev Returns the largest of two signed numbers.
     */
    function max(int256 a, int256 b) internal pure returns (int256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two signed numbers.
     */
    function min(int256 a, int256 b) internal pure returns (int256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two signed numbers without overflow.
     * The result is rounded towards zero.
     */
    function average(int256 a, int256 b) internal pure returns (int256) {
        // Formula from the book "Hacker's Delight"
        int256 x = (a & b) + ((a ^ b) >> 1);
        return x + (int256(uint256(x) >> 255) & (a ^ b));
    }

    /**
     * @dev Returns the absolute unsigned value of a signed value.
     */
    function abs(int256 n) internal pure returns (uint256) {
        unchecked {
            // must be unchecked in order to support `n = type(int256).min`
            return uint256(n >= 0 ? n : -n);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/Strings.sol)

pragma solidity ^0.8.20;

import {Math} from "./math/Math.sol";
import {SignedMath} from "./math/SignedMath.sol";

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant HEX_DIGITS = "0123456789abcdef";
    uint8 private constant ADDRESS_LENGTH = 20;

    /**
     * @dev The `value` string doesn't fit in the specified `length`.
     */
    error StringsInsufficientHexLength(uint256 value, uint256 length);

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        unchecked {
            uint256 length = Math.log10(value) + 1;
            string memory buffer = new string(length);
            uint256 ptr;
            /// @solidity memory-safe-assembly
            assembly {
                ptr := add(buffer, add(32, length))
            }
            while (true) {
                ptr--;
                /// @solidity memory-safe-assembly
                assembly {
                    mstore8(ptr, byte(mod(value, 10), HEX_DIGITS))
                }
                value /= 10;
                if (value == 0) break;
            }
            return buffer;
        }
    }

    /**
     * @dev Converts a `int256` to its ASCII `string` decimal representation.
     */
    function toStringSigned(int256 value) internal pure returns (string memory) {
        return string.concat(value < 0 ? "-" : "", toString(SignedMath.abs(value)));
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        unchecked {
            return toHexString(value, Math.log256(value) + 1);
        }
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        uint256 localValue = value;
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = HEX_DIGITS[localValue & 0xf];
            localValue >>= 4;
        }
        if (localValue != 0) {
            revert StringsInsufficientHexLength(value, length);
        }
        return string(buffer);
    }

    /**
     * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal
     * representation.
     */
    function toHexString(address addr) internal pure returns (string memory) {
        return toHexString(uint256(uint160(addr)), ADDRESS_LENGTH);
    }

    /**
     * @dev Returns true if the two strings are equal.
     */
    function equal(string memory a, string memory b) internal pure returns (bool) {
        return bytes(a).length == bytes(b).length && keccak256(bytes(a)) == keccak256(bytes(b));
    }
}

{
  "compilationTarget": {
    "contracts/chunkies/Chunkies.sol": "Chunkies"
  },
  "evmVersion": "paris",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 10
  },
  "remappings": []
}