// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/// @title: Andrew Mitchell's Manifold Extension
/// @author: Andrew Mitchell
/// @author: manifold.xyz

import "@manifoldxyz/libraries-solidity/contracts/access/IAdminControl.sol";
import "@manifoldxyz/creator-core-solidity/contracts/core/IERC721CreatorCore.sol";
import "@manifoldxyz/creator-core-solidity/contracts/extensions/CreatorExtension.sol";
import "@manifoldxyz/creator-core-solidity/contracts/extensions/ICreatorExtensionTokenURI.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/utils/math/SafeMath.sol";

import "./IManifoldERC721Edition.sol";

/**
 * 72 101 108 108 111  87 111 114 108 100 
 * 
 * Andrew Mitchell's custom contract extension.
 * mitchel1.eth, mitchel1.tez
 * Uses the Manifold ERC721 Edition Controller Implementation
 */
contract MitchellsExtension is CreatorExtension, ICreatorExtensionTokenURI, IManifoldERC721Edition, ReentrancyGuard {
    using SafeMath for uint256;
    using Strings for uint256;

    struct IndexRange {
        uint256 startIndex;
        uint256 count;
    }

    mapping(address => mapping(uint256 => string)) public _tokenPrefix;
    mapping(address => mapping(uint256 => uint256)) public _maxSupply;
    mapping(address => mapping(uint256 => uint256)) public _price;
    mapping(address => mapping(uint256 => uint256)) public _totalSupply;
    mapping(address => mapping(uint256 => IndexRange[])) public _indexRanges;
    mapping(address => mapping(uint256 => mapping(uint256 => string))) public _scripts;
    mapping(address => mapping(uint256 => mapping(uint256 => uint256))) _creationDates;
    mapping(address => mapping(uint256 => mapping(uint256 => address))) _creators;

    mapping(address => uint256) public _currentSeries;

    bool public pause = true;

    /**
     * @dev Only allows approved admins to call the specified function
     */
    modifier creatorAdminRequired(address creator) {
        require(IAdminControl(creator).isAdmin(msg.sender), "Must be owner or admin of creator contract");
        _;
    }
    
    function supportsInterface(bytes4 interfaceId) public view virtual override(CreatorExtension, IERC165) returns (bool) {
        return interfaceId == type(ICreatorExtensionTokenURI).interfaceId || interfaceId == type(IManifoldERC721Edition).interfaceId ||
               CreatorExtension.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IManifoldERC721Edition-totalSupply}.
     */
    function totalSupply(address creator, uint256 series) external view override returns(uint256) {
        return _totalSupply[creator][series];
    }

    /**
     * @dev See {IManifoldERC721Edition-maxSupply}.
     */
    function maxSupply(address creator, uint256 series) external view override returns(uint256) {
        return _maxSupply[creator][series];
    }

    /**
     * @dev See {IManifoldERC721Edition-createSeries}.
     */
    function createSeries(address creator, uint256 maxSupply_, string calldata prefix) external override creatorAdminRequired(creator) returns(uint256) {
        _currentSeries[creator] += 1;
        uint256 series = _currentSeries[creator];
        _maxSupply[creator][series] = maxSupply_;
        _tokenPrefix[creator][series] = prefix;
        emit SeriesCreated(msg.sender, creator, series, maxSupply_);
        return series;
    }

    /**
     * @dev See {IManifoldERC721Edition-latestSeries}.
     */
    function latestSeries(address creator) external view override returns(uint256) {
        return _currentSeries[creator];
    }

    /**
     * See {IManifoldERC721Edition-setTokenURIPrefix}.
     */
    function setTokenURIPrefix(address creator, uint256 series, string calldata prefix) external override creatorAdminRequired(creator) {
        require(series > 0 && series <= _currentSeries[creator], "Invalid series");
        _tokenPrefix[creator][series] = prefix;
    }

     /**
     * Set price of a series
     */
    function setPrice(address creator, uint256 series, uint256 price) external creatorAdminRequired(creator) {
        require(series > 0 && series <= _currentSeries[creator], "Invalid series");
        _price[creator][series] = price;
    }
    
    /**
     * @dev See {ICreatorExtensionTokenURI-tokenURI}.
     */
    function tokenURI(address creator, uint256 tokenId) external view override returns (string memory) {
        (uint256 series, uint256 index) = _tokenSeriesAndIndex(creator, tokenId);
        return string(abi.encodePacked(_tokenPrefix[creator][series], (index+1).toString()));
    }
    
    /**
     * @dev See {IManifoldERC721Edition-mint}.
     */
    function mint(address creator, uint256 series, address recipient, uint16 count) external override payable {
        require(!pause, "Sale has not started");
        require(count > 0, "Invalid amount requested");
        require(_totalSupply[creator][series]+count <= _maxSupply[creator][series], "Too many requested");
        require(msg.value >=_price[creator][series].mul(count), "Not enough ETH sent");
        uint256[] memory tokenIds = IERC721CreatorCore(creator).mintExtensionBatch(recipient, count);
        
        uint mintIndex = _totalSupply[creator][series];
        for (uint256 i = 0; i < count;) {
            _creators[creator][series][mintIndex] = recipient;
            _creationDates[creator][series][mintIndex] = block.number;
            mintIndex++;
            unchecked{i++;}
        }

        _updateIndexRanges(creator, series, tokenIds[0], count);
    }

    /**
     * @dev See {IManifoldERC721Edition-mint}.
     */
    function mintInternal(address creator, uint256 series, address[] calldata recipients) external override nonReentrant creatorAdminRequired(creator) {
        require(recipients.length > 0, "Invalid amount requested");
        require(_totalSupply[creator][series]+recipients.length <= _maxSupply[creator][series], "Too many requested");
        
        uint mintIndex = _totalSupply[creator][series];
        uint256 startIndex = IERC721CreatorCore(creator).mintExtension(recipients[0]);
        _creators[creator][series][mintIndex] = recipients[0];
        _creationDates[creator][series][mintIndex] = block.number;
        mintIndex ++;
        for (uint256 i = 1; i < recipients.length;) {
            IERC721CreatorCore(creator).mintExtension(recipients[i]);
            _creators[creator][series][mintIndex] = recipients[i];
            _creationDates[creator][series][mintIndex] = block.number;
            mintIndex++;
            unchecked{i++;}
        }
        _updateIndexRanges(creator, series, startIndex, recipients.length);
    }

    /**
     * @dev Update the index ranges, which is used to figure out the index from a tokenId
     */
    function _updateIndexRanges(address creator, uint256 series, uint256 startIndex, uint256 count) internal {
        IndexRange[] storage indexRanges = _indexRanges[creator][series];
        if (indexRanges.length == 0) {
           indexRanges.push(IndexRange(startIndex, count));
        } else {
          IndexRange storage lastIndexRange = indexRanges[indexRanges.length-1];
          if ((lastIndexRange.startIndex + lastIndexRange.count) == startIndex) {
             lastIndexRange.count += count;
          } else {
            indexRanges.push(IndexRange(startIndex, count));
          }
        }
        _totalSupply[creator][series] += count;
    }

    /**
     * @dev Index from tokenId
     */
    function _tokenSeriesAndIndex(address creator, uint256 tokenId) internal view returns(uint256, uint256) {
        require(_currentSeries[creator] > 0, "Invalid token");
        for (uint series=1; series <= _currentSeries[creator]; series++) {
            IndexRange[] memory indexRanges = _indexRanges[creator][series];
            uint256 offset;
            for (uint i = 0; i < indexRanges.length; i++) {
                IndexRange memory currentIndex = indexRanges[i];
                if (tokenId < currentIndex.startIndex) break;
                if (tokenId >= currentIndex.startIndex && tokenId < currentIndex.startIndex + currentIndex.count) {
                   return (series, tokenId - currentIndex.startIndex + offset);
                }
                offset += currentIndex.count;
            }
        }
        revert("Invalid token");
    }

    /**
     * @dev Token Hash used to generate art piece
     */
    function tokenHash(address creator, uint256 series, uint256 tokenId) public view returns (bytes32){
        require(_totalSupply[creator][series] >= tokenId, "Token nonexistent");
        return bytes32(keccak256(abi.encodePacked(address(this), _creationDates[creator][series][tokenId], _creators[creator][series][tokenId], tokenId)));
    }

    /**
     * @dev Pause is used to manage when mints can occur
     */
    function togglePause(address creator) public creatorAdminRequired(creator) {
        pause = !pause;
    }

    function addScriptChunk(address creator, uint256 series, uint256 index, string memory _chunk) public creatorAdminRequired(creator) {
        _scripts[creator][series][index]=_chunk;
    }

    function getScriptChunk(address creator, uint256 series, uint256 index) public view returns (string memory){
        return _scripts[creator][series][index];
    }

    function removeScriptChunk(address creator, uint256 series, uint256 index) public creatorAdminRequired(creator) {
        delete _scripts[creator][series][index];
    }

    function withdrawAll(address creator) public creatorAdminRequired(creator) payable {
        require(payable(msg.sender).send(address(this).balance));
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/// @author: manifold.xyz

import "@openzeppelin/contracts/utils/introspection/ERC165.sol";

/**
 * @dev Base creator extension variables
 */
abstract contract CreatorExtension is ERC165 {

    /**
     * @dev Legacy extension interface identifiers
     *
     * {IERC165-supportsInterface} needs to return 'true' for this interface
     * in order backwards compatible with older creator contracts
     */
    bytes4 constant internal LEGACY_EXTENSION_INTERFACE = 0x7005caad;

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165) returns (bool) {
        return interfaceId == LEGACY_EXTENSION_INTERFACE
            || super.supportsInterface(interfaceId);
    }
    
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)

pragma solidity ^0.8.0;

import "./IERC165.sol";

/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/// @author: manifold.xyz

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

/**
 * @dev Interface for admin control
 */
interface IAdminControl is IERC165 {

    event AdminApproved(address indexed account, address indexed sender);
    event AdminRevoked(address indexed account, address indexed sender);

    /**
     * @dev gets address of all admins
     */
    function getAdmins() external view returns (address[] memory);

    /**
     * @dev add an admin.  Can only be called by contract owner.
     */
    function approveAdmin(address admin) external;

    /**
     * @dev remove an admin.  Can only be called by contract owner.
     */
    function revokeAdmin(address admin) external;

    /**
     * @dev checks whether or not given address is an admin
     * Returns True if they are
     */
    function isAdmin(address admin) external view returns (bool);

}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/// @author: manifold.xyz

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

/**
 * @dev Core creator interface
 */
interface ICreatorCore is IERC165 {

    event ExtensionRegistered(address indexed extension, address indexed sender);
    event ExtensionUnregistered(address indexed extension, address indexed sender);
    event ExtensionBlacklisted(address indexed extension, address indexed sender);
    event MintPermissionsUpdated(address indexed extension, address indexed permissions, address indexed sender);
    event RoyaltiesUpdated(uint256 indexed tokenId, address payable[] receivers, uint256[] basisPoints);
    event DefaultRoyaltiesUpdated(address payable[] receivers, uint256[] basisPoints);
    event ExtensionRoyaltiesUpdated(address indexed extension, address payable[] receivers, uint256[] basisPoints);
    event ExtensionApproveTransferUpdated(address indexed extension, bool enabled);

    /**
     * @dev gets address of all extensions
     */
    function getExtensions() external view returns (address[] memory);

    /**
     * @dev add an extension.  Can only be called by contract owner or admin.
     * extension address must point to a contract implementing ICreatorExtension.
     * Returns True if newly added, False if already added.
     */
    function registerExtension(address extension, string calldata baseURI) external;

    /**
     * @dev add an extension.  Can only be called by contract owner or admin.
     * extension address must point to a contract implementing ICreatorExtension.
     * Returns True if newly added, False if already added.
     */
    function registerExtension(address extension, string calldata baseURI, bool baseURIIdentical) external;

    /**
     * @dev add an extension.  Can only be called by contract owner or admin.
     * Returns True if removed, False if already removed.
     */
    function unregisterExtension(address extension) external;

    /**
     * @dev blacklist an extension.  Can only be called by contract owner or admin.
     * This function will destroy all ability to reference the metadata of any tokens created
     * by the specified extension. It will also unregister the extension if needed.
     * Returns True if removed, False if already removed.
     */
    function blacklistExtension(address extension) external;

    /**
     * @dev set the baseTokenURI of an extension.  Can only be called by extension.
     */
    function setBaseTokenURIExtension(string calldata uri) external;

    /**
     * @dev set the baseTokenURI of an extension.  Can only be called by extension.
     * For tokens with no uri configured, tokenURI will return "uri+tokenId"
     */
    function setBaseTokenURIExtension(string calldata uri, bool identical) external;

    /**
     * @dev set the common prefix of an extension.  Can only be called by extension.
     * If configured, and a token has a uri set, tokenURI will return "prefixURI+tokenURI"
     * Useful if you want to use ipfs/arweave
     */
    function setTokenURIPrefixExtension(string calldata prefix) external;

    /**
     * @dev set the tokenURI of a token extension.  Can only be called by extension that minted token.
     */
    function setTokenURIExtension(uint256 tokenId, string calldata uri) external;

    /**
     * @dev set the tokenURI of a token extension for multiple tokens.  Can only be called by extension that minted token.
     */
    function setTokenURIExtension(uint256[] memory tokenId, string[] calldata uri) external;

    /**
     * @dev set the baseTokenURI for tokens with no extension.  Can only be called by owner/admin.
     * For tokens with no uri configured, tokenURI will return "uri+tokenId"
     */
    function setBaseTokenURI(string calldata uri) external;

    /**
     * @dev set the common prefix for tokens with no extension.  Can only be called by owner/admin.
     * If configured, and a token has a uri set, tokenURI will return "prefixURI+tokenURI"
     * Useful if you want to use ipfs/arweave
     */
    function setTokenURIPrefix(string calldata prefix) external;

    /**
     * @dev set the tokenURI of a token with no extension.  Can only be called by owner/admin.
     */
    function setTokenURI(uint256 tokenId, string calldata uri) external;

    /**
     * @dev set the tokenURI of multiple tokens with no extension.  Can only be called by owner/admin.
     */
    function setTokenURI(uint256[] memory tokenIds, string[] calldata uris) external;

    /**
     * @dev set a permissions contract for an extension.  Used to control minting.
     */
    function setMintPermissions(address extension, address permissions) external;

    /**
     * @dev Configure so transfers of tokens created by the caller (must be extension) gets approval
     * from the extension before transferring
     */
    function setApproveTransferExtension(bool enabled) external;

    /**
     * @dev get the extension of a given token
     */
    function tokenExtension(uint256 tokenId) external view returns (address);

    /**
     * @dev Set default royalties
     */
    function setRoyalties(address payable[] calldata receivers, uint256[] calldata basisPoints) external;

    /**
     * @dev Set royalties of a token
     */
    function setRoyalties(uint256 tokenId, address payable[] calldata receivers, uint256[] calldata basisPoints) external;

    /**
     * @dev Set royalties of an extension
     */
    function setRoyaltiesExtension(address extension, address payable[] calldata receivers, uint256[] calldata basisPoints) external;

    /**
     * @dev Get royalites of a token.  Returns list of receivers and basisPoints
     */
    function getRoyalties(uint256 tokenId) external view returns (address payable[] memory, uint256[] memory);
    
    // Royalty support for various other standards
    function getFeeRecipients(uint256 tokenId) external view returns (address payable[] memory);
    function getFeeBps(uint256 tokenId) external view returns (uint[] memory);
    function getFees(uint256 tokenId) external view returns (address payable[] memory, uint256[] memory);
    function royaltyInfo(uint256 tokenId, uint256 value) external view returns (address, uint256);

}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/// @author: manifold.xyz

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

/**
 * @dev Implement this if you want your extension to have overloadable URI's
 */
interface ICreatorExtensionTokenURI is IERC165 {

    /**
     * Get the uri for a given creator/tokenId
     */
    function tokenURI(address creator, uint256 tokenId) external view returns (string memory);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

/**
 * @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

pragma solidity ^0.8.0;

/// @author: manifold.xyz

import "./ICreatorCore.sol";

/**
 * @dev Core ERC721 creator interface
 */
interface IERC721CreatorCore is ICreatorCore {

    /**
     * @dev mint a token with no extension. Can only be called by an admin.
     * Returns tokenId minted
     */
    function mintBase(address to) external returns (uint256);

    /**
     * @dev mint a token with no extension. Can only be called by an admin.
     * Returns tokenId minted
     */
    function mintBase(address to, string calldata uri) external returns (uint256);

    /**
     * @dev batch mint a token with no extension. Can only be called by an admin.
     * Returns tokenId minted
     */
    function mintBaseBatch(address to, uint16 count) external returns (uint256[] memory);

    /**
     * @dev batch mint a token with no extension. Can only be called by an admin.
     * Returns tokenId minted
     */
    function mintBaseBatch(address to, string[] calldata uris) external returns (uint256[] memory);

    /**
     * @dev mint a token. Can only be called by a registered extension.
     * Returns tokenId minted
     */
    function mintExtension(address to) external returns (uint256);

    /**
     * @dev mint a token. Can only be called by a registered extension.
     * Returns tokenId minted
     */
    function mintExtension(address to, string calldata uri) external returns (uint256);

    /**
     * @dev batch mint a token. Can only be called by a registered extension.
     * Returns tokenIds minted
     */
    function mintExtensionBatch(address to, uint16 count) external returns (uint256[] memory);

    /**
     * @dev batch mint a token. Can only be called by a registered extension.
     * Returns tokenId minted
     */
    function mintExtensionBatch(address to, string[] calldata uris) external returns (uint256[] memory);

    /**
     * @dev burn a token. Can only be called by token owner or approved address.
     * On burn, calls back to the registered extension's onBurn method
     */
    function burn(uint256 tokenId) external;

}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/// @author: manifold.xyz

/**
 * Manifold ERC721 Edition Controller interface
 */
interface IManifoldERC721Edition {
    event SeriesCreated(address caller, address creator, uint256 series, uint256 maxSupply);

    /**
     * @dev Create a new series.  Returns the series id.
     */
    function createSeries(address creator, uint256 maxSupply, string calldata prefix) external returns(uint256);

    /**
     * @dev Get the latest series created.
     */
    function latestSeries(address creator) external view returns(uint256);

    /**
     * @dev Set the token uri prefix
     */
    function setTokenURIPrefix(address creator, uint256 series, string calldata prefix) external;
    
    /**
     * @dev Mint NFTs to a single recipient
     */
    function mint(address creator, uint256 series, address recipient, uint16 count) external payable;

    /**
     * @dev Mint NFTS to the recipients
     */
    function mintInternal(address creator, uint256 series, address[] calldata recipients) external;

    /**
     * @dev Total supply of editions
     */
    function totalSupply(address creator, uint256 series) external view returns(uint256);

    /**
     * @dev Max supply of editions
     */
    function maxSupply(address creator, uint256 series) external view returns(uint256);
}

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

pragma solidity ^0.8.0;

/**
 * @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;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @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() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

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

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/math/SafeMath.sol)

pragma solidity ^0.8.0;

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
 * now has built in overflow checking.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    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 substraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    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.
     *
     * _Available since v3.4._
     */
    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.
     *
     * _Available since v3.4._
     */
    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.
     *
     * _Available since v3.4._
     */
    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 addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        return a + b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return a - b;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        return a * b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)

pragma solidity ^0.8.0;

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        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_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}

{
  "compilationTarget": {
    "contracts/Contract2.sol": "MitchellsExtension"
  },
  "evmVersion": "london",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": []
}