// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     *
     * Furthermore, `isContract` will also return true if the target contract within
     * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
     * which only has an effect at the end of a transaction.
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://consensys.net/diligence/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.8.0/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // Look for revert reason and bubble it up if present
        if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

// Copyright 2023-, Semiotic AI, Inc.
// SPDX-License-Identifier: Apache-2.0
pragma solidity 0.8.18;

import {ECDSA} from "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";

/**
 * @title AllocationIDTracker
 * @dev This contract tracks the allocation IDs of the RAVs that have been submitted to
 *      ensure that each allocation ID is only used once. It is external to escrow
 *      contract to allow for updating the escrow contract without losing the list of
 *      used allocation IDs.
 * @notice This contract is intended to be used with the `Escrow` contract.
 */
contract AllocationIDTracker {
    // senders used allocation IDs
    mapping(address sender => mapping(address allocationId => bool isUsed))
        private _sendersUsedAllocationIDs;

    // Custom error to indicate the provided allocation ID was previously claimed and no longer valid
    error AllocationIDPreviouslyClaimed(address sender, address allocationID);

    // Custom error to indicate the provided proof is not valid
    error InvalidProof();

    /**
     * @dev Emitted when an allocation ID is used.
     */
    event AllocationIDUsed(
        address indexed sender,
        address indexed allocationID
    );

    /**
     * @dev Checks if an allocation ID has been used.
     * @param allocationID The allocation ID to check.
     * @return True if the allocation ID has been used, false otherwise.
     */
    function isAllocationIDUsed(
        address sender,
        address allocationID
    ) external view returns (bool) {
        return _sendersUsedAllocationIDs[sender][allocationID];
    }

    /**
     * @dev Marks an allocation ID as used.
     * @param sender The sender of the token to receiver.
     * @param allocationID The allocation ID to mark as used.
     * @param proof ECDSA Proof signed by the receiver's allocationID consisting of packed (chainID, sender address, allocationID, escrow contract address).
     * @notice REVERT with error:
     *               - AllocationIDPreviouslyClaimed: If the (sender, allocationID) pair was previously claimed
     *               - InvalidProof: If the proof is not valid
     */
    function useAllocationID(
        address sender,
        address allocationID,
        bytes calldata proof
    ) external {
        if (_sendersUsedAllocationIDs[sender][allocationID] == true) {
            revert AllocationIDPreviouslyClaimed(sender, allocationID);
        }
        verifyProof(proof, sender, allocationID);

        _sendersUsedAllocationIDs[sender][allocationID] = true;
        emit AllocationIDUsed(sender, allocationID);
    }

    /**
     * @dev Verifies a proof of allocationID ownership.
     * @param proof ECDSA Proof signed by the receiver's allocationID consisting of packed (chainID, sender address, allocationID, escrow contract address).
     * @param sender The sender of the token to receiver.
     * @param allocationID The allocation ID to verify.
     * @notice REVERT with error:
     *               - InvalidProof: If the proof is not valid
     */
    function verifyProof(
        bytes calldata proof,
        address sender,
        address allocationID
    ) private view {
        bytes32 messageHash = keccak256(
            abi.encodePacked(block.chainid, sender, allocationID, msg.sender)
        );
        bytes32 digest = ECDSA.toEthSignedMessageHash(messageHash);
        if (ECDSA.recover(digest, proof) != allocationID) {
            revert InvalidProof();
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/cryptography/ECDSA.sol)

pragma solidity ^0.8.0;

import "../Strings.sol";

/**
 * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
 *
 * These functions can be used to verify that a message was signed by the holder
 * of the private keys of a given address.
 */
library ECDSA {
    enum RecoverError {
        NoError,
        InvalidSignature,
        InvalidSignatureLength,
        InvalidSignatureS,
        InvalidSignatureV // Deprecated in v4.8
    }

    function _throwError(RecoverError error) private pure {
        if (error == RecoverError.NoError) {
            return; // no error: do nothing
        } else if (error == RecoverError.InvalidSignature) {
            revert("ECDSA: invalid signature");
        } else if (error == RecoverError.InvalidSignatureLength) {
            revert("ECDSA: invalid signature length");
        } else if (error == RecoverError.InvalidSignatureS) {
            revert("ECDSA: invalid signature 's' value");
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature` or error string. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     *
     * Documentation for signature generation:
     * - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
     * - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
     *
     * _Available since v4.3._
     */
    function tryRecover(bytes32 hash, bytes memory signature) internal pure returns (address, RecoverError) {
        if (signature.length == 65) {
            bytes32 r;
            bytes32 s;
            uint8 v;
            // ecrecover takes the signature parameters, and the only way to get them
            // currently is to use assembly.
            /// @solidity memory-safe-assembly
            assembly {
                r := mload(add(signature, 0x20))
                s := mload(add(signature, 0x40))
                v := byte(0, mload(add(signature, 0x60)))
            }
            return tryRecover(hash, v, r, s);
        } else {
            return (address(0), RecoverError.InvalidSignatureLength);
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     */
    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, signature);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `r` and `vs` short-signature fields separately.
     *
     * See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]
     *
     * _Available since v4.3._
     */
    function tryRecover(bytes32 hash, bytes32 r, bytes32 vs) internal pure returns (address, RecoverError) {
        bytes32 s = vs & bytes32(0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff);
        uint8 v = uint8((uint256(vs) >> 255) + 27);
        return tryRecover(hash, v, r, s);
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `r and `vs` short-signature fields separately.
     *
     * _Available since v4.2._
     */
    function recover(bytes32 hash, bytes32 r, bytes32 vs) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, r, vs);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `v`,
     * `r` and `s` signature fields separately.
     *
     * _Available since v4.3._
     */
    function tryRecover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) internal pure returns (address, RecoverError) {
        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
        // the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most
        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
        //
        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
        // these malleable signatures as well.
        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return (address(0), RecoverError.InvalidSignatureS);
        }

        // If the signature is valid (and not malleable), return the signer address
        address signer = ecrecover(hash, v, r, s);
        if (signer == address(0)) {
            return (address(0), RecoverError.InvalidSignature);
        }

        return (signer, RecoverError.NoError);
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `v`,
     * `r` and `s` signature fields separately.
     */
    function recover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, v, r, s);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Returns an Ethereum Signed Message, created from a `hash`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32 message) {
        // 32 is the length in bytes of hash,
        // enforced by the type signature above
        /// @solidity memory-safe-assembly
        assembly {
            mstore(0x00, "\x19Ethereum Signed Message:\n32")
            mstore(0x1c, hash)
            message := keccak256(0x00, 0x3c)
        }
    }

    /**
     * @dev Returns an Ethereum Signed Message, created from `s`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes memory s) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n", Strings.toString(s.length), s));
    }

    /**
     * @dev Returns an Ethereum Signed Typed Data, created from a
     * `domainSeparator` and a `structHash`. This produces hash corresponding
     * to the one signed with the
     * https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`]
     * JSON-RPC method as part of EIP-712.
     *
     * See {recover}.
     */
    function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32 data) {
        /// @solidity memory-safe-assembly
        assembly {
            let ptr := mload(0x40)
            mstore(ptr, "\x19\x01")
            mstore(add(ptr, 0x02), domainSeparator)
            mstore(add(ptr, 0x22), structHash)
            data := keccak256(ptr, 0x42)
        }
    }

    /**
     * @dev Returns an Ethereum Signed Data with intended validator, created from a
     * `validator` and `data` according to the version 0 of EIP-191.
     *
     * See {recover}.
     */
    function toDataWithIntendedValidatorHash(address validator, bytes memory data) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\x19\x00", validator, data));
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/cryptography/EIP712.sol)

pragma solidity ^0.8.8;

import "./ECDSA.sol";
import "../ShortStrings.sol";
import "../../interfaces/IERC5267.sol";

/**
 * @dev https://eips.ethereum.org/EIPS/eip-712[EIP 712] is a standard for hashing and signing of typed structured data.
 *
 * The encoding specified in the EIP is very generic, and such a generic implementation in Solidity is not feasible,
 * thus this contract does not implement the encoding itself. Protocols need to implement the type-specific encoding
 * they need in their contracts using a combination of `abi.encode` and `keccak256`.
 *
 * This contract implements the EIP 712 domain separator ({_domainSeparatorV4}) that is used as part of the encoding
 * scheme, and the final step of the encoding to obtain the message digest that is then signed via ECDSA
 * ({_hashTypedDataV4}).
 *
 * The implementation of the domain separator was designed to be as efficient as possible while still properly updating
 * the chain id to protect against replay attacks on an eventual fork of the chain.
 *
 * NOTE: This contract implements the version of the encoding known as "v4", as implemented by the JSON RPC method
 * https://docs.metamask.io/guide/signing-data.html[`eth_signTypedDataV4` in MetaMask].
 *
 * NOTE: In the upgradeable version of this contract, the cached values will correspond to the address, and the domain
 * separator of the implementation contract. This will cause the `_domainSeparatorV4` function to always rebuild the
 * separator from the immutable values, which is cheaper than accessing a cached version in cold storage.
 *
 * _Available since v3.4._
 *
 * @custom:oz-upgrades-unsafe-allow state-variable-immutable state-variable-assignment
 */
abstract contract EIP712 is IERC5267 {
    using ShortStrings for *;

    bytes32 private constant _TYPE_HASH =
        keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)");

    // Cache the domain separator as an immutable value, but also store the chain id that it corresponds to, in order to
    // invalidate the cached domain separator if the chain id changes.
    bytes32 private immutable _cachedDomainSeparator;
    uint256 private immutable _cachedChainId;
    address private immutable _cachedThis;

    bytes32 private immutable _hashedName;
    bytes32 private immutable _hashedVersion;

    ShortString private immutable _name;
    ShortString private immutable _version;
    string private _nameFallback;
    string private _versionFallback;

    /**
     * @dev Initializes the domain separator and parameter caches.
     *
     * The meaning of `name` and `version` is specified in
     * https://eips.ethereum.org/EIPS/eip-712#definition-of-domainseparator[EIP 712]:
     *
     * - `name`: the user readable name of the signing domain, i.e. the name of the DApp or the protocol.
     * - `version`: the current major version of the signing domain.
     *
     * NOTE: These parameters cannot be changed except through a xref:learn::upgrading-smart-contracts.adoc[smart
     * contract upgrade].
     */
    constructor(string memory name, string memory version) {
        _name = name.toShortStringWithFallback(_nameFallback);
        _version = version.toShortStringWithFallback(_versionFallback);
        _hashedName = keccak256(bytes(name));
        _hashedVersion = keccak256(bytes(version));

        _cachedChainId = block.chainid;
        _cachedDomainSeparator = _buildDomainSeparator();
        _cachedThis = address(this);
    }

    /**
     * @dev Returns the domain separator for the current chain.
     */
    function _domainSeparatorV4() internal view returns (bytes32) {
        if (address(this) == _cachedThis && block.chainid == _cachedChainId) {
            return _cachedDomainSeparator;
        } else {
            return _buildDomainSeparator();
        }
    }

    function _buildDomainSeparator() private view returns (bytes32) {
        return keccak256(abi.encode(_TYPE_HASH, _hashedName, _hashedVersion, block.chainid, address(this)));
    }

    /**
     * @dev Given an already https://eips.ethereum.org/EIPS/eip-712#definition-of-hashstruct[hashed struct], this
     * function returns the hash of the fully encoded EIP712 message for this domain.
     *
     * This hash can be used together with {ECDSA-recover} to obtain the signer of a message. For example:
     *
     * ```solidity
     * bytes32 digest = _hashTypedDataV4(keccak256(abi.encode(
     *     keccak256("Mail(address to,string contents)"),
     *     mailTo,
     *     keccak256(bytes(mailContents))
     * )));
     * address signer = ECDSA.recover(digest, signature);
     * ```
     */
    function _hashTypedDataV4(bytes32 structHash) internal view virtual returns (bytes32) {
        return ECDSA.toTypedDataHash(_domainSeparatorV4(), structHash);
    }

    /**
     * @dev See {EIP-5267}.
     *
     * _Available since v4.9._
     */
    function eip712Domain()
        public
        view
        virtual
        override
        returns (
            bytes1 fields,
            string memory name,
            string memory version,
            uint256 chainId,
            address verifyingContract,
            bytes32 salt,
            uint256[] memory extensions
        )
    {
        return (
            hex"0f", // 01111
            _name.toStringWithFallback(_nameFallback),
            _version.toStringWithFallback(_versionFallback),
            block.chainid,
            address(this),
            bytes32(0),
            new uint256[](0)
        );
    }
}

// Copyright 2023-, Semiotic AI, Inc.
// SPDX-License-Identifier: Apache-2.0
pragma solidity 0.8.18;

import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {ECDSA} from "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
import {TAPVerifier} from "./TAPVerifier.sol";
import {AllocationIDTracker} from "./AllocationIDTracker.sol";
import {IStaking} from "./IStaking.sol";

/**
 * @title Escrow
 * @dev This contract allows `senders` to deposit escrow for specific `receivers`,
 *      which can later be redeemed using Receipt Aggregate Vouchers (`RAV`) signed
 *      by an authorized `signer`. `Senders` can deposit escrow for `receivers`,
 *      authorize `signers` to create signed `RAVs`, and withdraw escrow after a
 *      set `thawingPeriod` number of seconds. `Receivers` can redeem signed `RAVs` to
 *      claim escrow.
 * @notice This contract uses the `TAPVerifier` contract for recovering signer addresses
 *         from `RAVs`.
 * @notice CAUTIONARY NOTE: Upon observing a thaw event, indexers should act promptly. If the thaw concerns an authorized signer,
 *         treat it as no longer valid for initiating new engagements. For ongoing engagements, efforts should be made to conclude
 *         them swiftly. If funds are in a thawing state, anticipate an imminent withdrawal. Even if actions post-thaw are postponed,
 *         it's prudent to act as though they've already taken place to sidestep potential pitfalls.
 */
contract Escrow {
    using SafeERC20 for IERC20;

    struct EscrowAccount {
        uint256 balance; // Total escrow balance for a sender-receiver pair
        uint256 amountThawing; // Amount of escrow currently being thawed
        uint256 thawEndTimestamp; // Timestamp at which thawing period ends (zero if not thawing)
    }

    struct SenderAuthorization {
        address sender; // Sender the signer is authorized to sign for
        uint256 thawEndTimestamp; // Timestamp at which thawing period ends (zero if not thawing)
    }

    // Stores how much escrow each sender has deposited for each receiver, as well as thawing information
    mapping(address sender => mapping(address receiver => EscrowAccount escrowAccount))
        public escrowAccounts;

    // Map of signer to authorized signer information
    mapping(address signer => SenderAuthorization authorizedSigner)
        public authorizedSigners;

    // The ERC20 token used for escrow
    IERC20 public immutable escrowToken;

    // Graph staking contract
    IStaking public immutable staking;

    // The contract used for verifying receipt aggregate vouchers
    TAPVerifier public immutable tapVerifier;

    // The contract used for tracking used allocation IDs
    AllocationIDTracker public immutable allocationIDTracker;

    // The duration (in seconds) in which escrow funds are thawing before they can be withdrawn
    uint256 public immutable withdrawEscrowThawingPeriod;

    // The duration (in seconds) in which a signer is thawing before they can be revoked
    uint256 public immutable revokeSignerThawingPeriod;

    // The maximum thawing period (in seconds) for both escrow withdrawal and signer revocation
    // This is a precautionary measure to avoid inadvertedly locking funds for too long
    uint256 public constant MAX_THAWING_PERIOD = 90 days;

    // Custom error to indicate insufficient escrow balance
    error InsufficientEscrow(uint256 available, uint256 required);

    // Custom error to indicate insufficient thaw amount (must be greater than 0)
    error InsufficientThawAmount();

    // Custom error to indicate escrow is still thawing
    error EscrowStillThawing(
        uint256 currentTimestamp,
        uint256 thawEndTimestamp
    );

    // Custom error to indicate escrow thawing has not been initiated
    error EscrowNotThawing();

    // Custom error to indicate invalid signer proof
    error InvalidSignerProof();

    // Custom error to indicate provided signer is not one of provided senders authorized signers
    error SignerNotAuthorizedBySender(address signer, address sender);

    // Custom error to indicate signer already authorized
    error SignerAlreadyAuthorized(address signer, address authorizingSender);

    // Custom error to indicate signer is still thawing
    error SignerStillThawing(
        uint256 currentTimestamp,
        uint256 thawEndTimestamp
    );

    // Custom error to indicate signer thawing has not been initiated
    error SignerNotThawing();

    // Custom error to indicate invalid RAV signer
    error InvalidRAVSigner();

    // Custom error to indicate the signer is not currently authorized by any sender
    error SignerNotAuthorized();

    // Custom error to indicate inputs length mismatch
    error InputsLengthMismatch();

    // Custom error to indicate thawing parameter is off bounds
    error RevokeSignerThawingTooLong(uint256 thawingPeriod, uint256 maxThawingPeriod);

    // Custom error to indicate thawing parameter is off bounds
    error WithdrawEscrowThawingTooLong(uint256 thawingPeriod, uint256 maxThawingPeriod);

    /**
     * @dev Emitted when escrow is deposited for a receiver.
     */
    event Deposit(
        address indexed sender,
        address indexed receiver,
        uint256 amount
    );

    /**
     * @dev Emitted when escrow is redeemed by a receiver.
     * @notice If the actual amount redeemed is less than the expected amount,
     *         there was insufficient escrow available to redeem.
     */
    event Redeem(
        address indexed sender,
        address indexed receiver,
        address indexed allocationID,
        uint256 expectedAmount,
        uint256 actualAmount
    );

    /**
     * @dev Emitted when a thaw request is made for escrow.
     */
    event Thaw(
        address indexed sender,
        address indexed receiver,
        uint256 amount,
        uint256 totalAmountThawing,
        uint256 thawEndTimestamp
    );

    /**
     * @dev Emitted when a thaw request is cancelled for escrow.
     */
    event CancelThaw(address indexed sender, address indexed receiver);

    /**
     * @dev Emitted when a thaw request is made for authorized signer
     */
    event ThawSigner(
        address indexed sender,
        address indexed authorizedSigner,
        uint256 thawEndTimestamp
    );

    /**
     * @dev Emitted when the thawing of a signer is cancelled
     */
    event CancelThawSigner(
        address indexed sender,
        address indexed authorizedSigner,
        uint256 thawEndTimestamp
    );

    /**
     * @dev Emitted when a authorized signer has been revoked
     */
    event RevokeAuthorizedSigner(
        address indexed sender,
        address indexed authorizedSigner
    );

    /**
     * @dev Emitted when thawed escrow is withdrawn by the sender.
     */
    event Withdraw(
        address indexed sender,
        address indexed receiver,
        uint256 amount
    );

    /**
     * @dev Emitted when a signer is authorized to sign RAVs for a sender.
     */
    event AuthorizeSigner(address indexed signer, address indexed sender);

    constructor(
        address escrowToken_,
        address staking_,
        address tapVerifier_,
        address allocationIDTracker_,
        uint256 withdrawEscrowThawingPeriod_,
        uint256 revokeSignerThawingPeriod_
    ) {
        if (withdrawEscrowThawingPeriod_ > MAX_THAWING_PERIOD) {
            revert WithdrawEscrowThawingTooLong({
                thawingPeriod: withdrawEscrowThawingPeriod_,
                maxThawingPeriod: MAX_THAWING_PERIOD
            });
        }
        if(revokeSignerThawingPeriod_ > MAX_THAWING_PERIOD) {
            revert RevokeSignerThawingTooLong({
                thawingPeriod: revokeSignerThawingPeriod_,
                maxThawingPeriod: MAX_THAWING_PERIOD
            });
        }

        escrowToken = IERC20(escrowToken_);
        staking = IStaking(staking_);
        tapVerifier = TAPVerifier(tapVerifier_);
        allocationIDTracker = AllocationIDTracker(allocationIDTracker_);
        withdrawEscrowThawingPeriod = withdrawEscrowThawingPeriod_;
        revokeSignerThawingPeriod = revokeSignerThawingPeriod_;

        // Approve the staking contract to pull any amount of tokens from this contract
        // NOTE: this is done to increase gas efficiency instead of approving on each voucher redeem
        escrowToken.approve(address(staking), type(uint256).max);
    }

    /**
     * @dev Deposits escrow for a receiver.
     * @param receiver Address of the receiver.
     * @param amount Amount of escrow to deposit.
     * @notice The escrow must be approved for transfer by the sender.
     * @notice REVERT: this function will revert if the escrow transfer fails.
     */
    function deposit(address receiver, uint256 amount) external {
        escrowAccounts[msg.sender][receiver].balance += amount;
        escrowToken.safeTransferFrom(msg.sender, address(this), amount);
        emit Deposit(msg.sender, receiver, amount);
    }

    /**
     * @dev Deposits escrow for multiple receivers.
     * @param receivers Array of addresses of the receivers.
     * @param amounts Array of amounts of escrow to deposit.
     * @notice The escrow must be approved for transfer by the sender.
     * @notice REVERT: this function will revert if the escrow transfer fails.
     * @notice REVERT: if the length of the receivers and amounts arrays do not match.
     */
    function depositMany(
        address[] calldata receivers,
        uint256[] calldata amounts
    ) external {
        if (receivers.length != amounts.length) {
            revert InputsLengthMismatch();
        }

        uint256 totalAmount = 0;
        for (uint256 i = 0; i < receivers.length; i++) {
            address receiver = receivers[i];
            uint256 amount = amounts[i];

            totalAmount += amount;
            escrowAccounts[msg.sender][receiver].balance += amount;
            emit Deposit(msg.sender, receiver, amount);
        }

        escrowToken.safeTransferFrom(msg.sender, address(this), totalAmount);
    }

    /**
     * @dev Requests to thaw a specific amount of escrow from a receiver's escrow account.
     *      If requested amount is zero any thawing in progress will be cancelled. If requested
     *      amount is greater than zero any thawing in progress will be cancelled and a new
     *     thawing request will be initiated.
     * @param receiver Address of the receiver the escrow account is for.
     * @param amount Amount of escrow to thaw.
     * @notice WARNING: Requesting to thaw escrow funds serves as an indication that these funds are soon to be withdrawn.
     * Receivers with commitments linked to the thawing funds should quickly wrap up those commitments.
     * At the same time, receivers should avoid starting new engagements tied to the thawing funds.
     * After the thawing process, the funds should be viewed as withdrawn, irrespective of the actual withdrawal status.
     * @notice REVERT with error:
     *               - InsufficientThawAmount: if the requested amount is zero and there is no
     *                 escrow currently thawing
     *               - InsufficientEscrow: if the sender receiver escrow account does
     *                 not have enough escrow (greater than `amount`)
     */
    function thaw(address receiver, uint256 amount) external {
        EscrowAccount storage account = escrowAccounts[msg.sender][receiver];
        if (amount == 0) {
            // if amount thawing is zero and requested amount is zero this is an invalid request(#36).
            // otherwise if amount thawing is greater than zero and requested amount is zero this
            // is a cancel thaw request.
            if (account.amountThawing == 0) {
                revert InsufficientThawAmount();
            }
            account.amountThawing = 0;
            account.thawEndTimestamp = 0;
            emit CancelThaw(msg.sender, receiver);
            return;
        }

        // Check if the escrow balance is sufficient
        if (account.balance < amount) {
            revert InsufficientEscrow({
                available: account.balance,
                required: amount
            });
        }

        // Set amount to thaw
        account.amountThawing = amount;
        // Set when the thaw is complete (thawing period number of seconds after current timestamp)
        account.thawEndTimestamp =
            block.timestamp +
            withdrawEscrowThawingPeriod;

        emit Thaw(
            msg.sender,
            receiver,
            amount,
            account.amountThawing,
            account.thawEndTimestamp
        );
    }

    /**
     * @dev Withdraws all thawed escrow from a receiver's escrow account.
     * @param receiver Address of the receiver.
     * @notice REVERT with error:
     *               - EscrowNotThawing: There is no escrow currently thawing
     *               - EscrowStillThawing: ThawEndTimestamp has not been reached
     *                 for escrow currently thawing
     */
    function withdraw(address receiver) external {
        EscrowAccount storage account = escrowAccounts[msg.sender][receiver];
        if (account.thawEndTimestamp == 0) {
            revert EscrowNotThawing();
        }

        if (account.thawEndTimestamp > block.timestamp) {
            revert EscrowStillThawing({
                currentTimestamp: block.timestamp,
                thawEndTimestamp: account.thawEndTimestamp
            });
        }

        // Amount is the minimum between the amount being thawed and the actual balance
        uint256 amount = account.amountThawing > account.balance
            ? account.balance
            : account.amountThawing;

        account.balance -= amount; // Reduce the balance by the withdrawn amount (no underflow risk)
        account.amountThawing = 0;
        account.thawEndTimestamp = 0;
        escrowToken.safeTransfer(msg.sender, amount);
        emit Withdraw(msg.sender, receiver, amount);
    }

    /**
     * @dev Authorizes a signer to sign RAVs for the sender.
     * @param signer Address of the authorized signer.
     * @param proof The proof provided by the signer to authorize the sender, consisting of packed (chainID, proof deadline, sender address).
     * @dev The proof deadline is the timestamp at which the proof expires. The proof is susceptible to replay attacks until the deadline is reached.
     * @notice REVERT with error:
     *               - SignerAlreadyAuthorized: Signer is currently authorized for a sender
     *               - InvalidSignerProof: The provided signer proof is invalid
     */
    function authorizeSigner(
        address signer,
        uint256 proofDeadline,
        bytes calldata proof
    ) external {
        if (authorizedSigners[signer].sender != address(0)) {
            revert SignerAlreadyAuthorized(
                signer,
                authorizedSigners[signer].sender
            );
        }

        verifyAuthorizedSignerProof(proof, proofDeadline, signer);

        authorizedSigners[signer].sender = msg.sender;
        authorizedSigners[signer].thawEndTimestamp = 0;
        emit AuthorizeSigner(signer, msg.sender);
    }

    /**
     * @dev Starts thawing a signer to be removed from the authorized signers list.
     * @param signer Address of the signer to remove.
     * @notice WARNING: Thawing a signer alerts receivers that signatures from that signer will soon be deemed invalid.
     * Receivers without existing signed receipts or RAVs from this signer should treat them as unauthorized.
     * Those with existing signed documents from this signer should work towards settling their engagements.
     * Once a signer is thawed, they should be viewed as revoked regardless of their revocation status.
     * @notice REVERT with error:
     *               - SignerNotAuthorizedBySender: The provided signer is either not authorized or
     *                 authorized by a different sender
     */
    function thawSigner(address signer) external {
        SenderAuthorization storage authorization = authorizedSigners[signer];

        if (authorization.sender != msg.sender) {
            revert SignerNotAuthorizedBySender(
                signer,
                authorizedSigners[signer].sender
            );
        }

        authorization.thawEndTimestamp =
            block.timestamp +
            revokeSignerThawingPeriod;
        emit ThawSigner(
            authorization.sender,
            signer,
            authorization.thawEndTimestamp
        );
    }

    /**
     * @dev Stops thawing a signer.
     * @param signer Address of the signer to stop thawing.
     * @notice REVERT with error:
     *               - SignerNotAuthorizedBySender: The provided signer is either not authorized or
     *                 authorized by a different sender
     */
    function cancelThawSigner(address signer) external {
        SenderAuthorization storage authorization = authorizedSigners[signer];

        if (authorization.sender != msg.sender) {
            revert SignerNotAuthorizedBySender(
                signer,
                authorizedSigners[signer].sender
            );
        }

        authorization.thawEndTimestamp = 0;
        emit CancelThawSigner(
            authorization.sender,
            signer,
            authorization.thawEndTimestamp
        );
    }

    /**
     * @dev Revokes a signer from the authorized signers list if thawed.
     * @param signer Address of the signer to remove.
     * @notice REVERT with error:
     *               - SignerNotAuthorizedBySender: The provided signer is either not authorized or
     *                 authorized by a different sender
     *               - SignerNotThawing: No thaw was initiated for the provided signer
     *               - SignerStillThawing: ThawEndTimestamp has not been reached
     *                 for provided signer
     */
    function revokeAuthorizedSigner(address signer) external {
        SenderAuthorization storage authorization = authorizedSigners[signer];

        if (authorization.sender != msg.sender) {
            revert SignerNotAuthorizedBySender(
                signer,
                authorizedSigners[signer].sender
            );
        }

        if (authorization.thawEndTimestamp == 0) {
            revert SignerNotThawing();
        }

        if (authorization.thawEndTimestamp > block.timestamp) {
            revert SignerStillThawing({
                currentTimestamp: block.timestamp,
                thawEndTimestamp: authorization.thawEndTimestamp
            });
        }

        delete authorizedSigners[signer];
        emit RevokeAuthorizedSigner(authorization.sender, signer);
    }

    /**
     * @dev Redeems escrow (up to amount available in escrow) for a receiver using a signed RAV.
     * @param signedRAV Signed RAV containing the receiver and escrow amount.
     * @param allocationIDProof Proof of allocationID ownership.
     * @notice If a signer or funds are in the thawing process, exercise caution. Thawing indicates upcoming removals.
     *         For in-depth understanding, refer to the respective documentation sections on thawing signers and funds.
     * @notice Will accept redeem even if escrow account balance is below RAV valueAggregate. Check escrow balance before
     *         redeeming to ensure expected funds are available. Only one succesfully redeem is allowed for
     *         (sender, allocationID) pair.
     * @notice REVERT: This function may revert if ECDSA.recover fails, check Open Zeppelin ECDSA library for details.
     * @notice REVERT with error:
     *               - InvalidRAVSigner: If the RAV is signed by a signer who is not authorized by any sender
     *               - AllocationIDTracker.AllocationIDPreviouslyClaimed: If the allocation ID was previously claimed
     *               - AllocationIDTracker.InvalidProof: If the allocation ID ownership proof is not valid
     */
    function redeem(
        TAPVerifier.SignedRAV calldata signedRAV,
        bytes calldata allocationIDProof
    ) external {
        address signer = tapVerifier.recoverRAVSigner(signedRAV);

        if (authorizedSigners[signer].sender == address(0)) {
            revert InvalidRAVSigner();
        }

        address sender = authorizedSigners[signer].sender;
        address receiver = staking
            .getAllocation(signedRAV.rav.allocationId)
            .indexer;
        address allocationId = signedRAV.rav.allocationId;

        // Amount is the minimum between the amount owed on rav and the actual balance
        uint256 amount = signedRAV.rav.valueAggregate >
            escrowAccounts[sender][receiver].balance
            ? escrowAccounts[sender][receiver].balance
            : signedRAV.rav.valueAggregate;

        escrowAccounts[sender][receiver].balance -= amount;

        allocationIDTracker.useAllocationID(
            sender,
            allocationId,
            allocationIDProof
        );
        staking.collect(amount, allocationId);
        emit Redeem(
            sender,
            receiver,
            signedRAV.rav.allocationId,
            signedRAV.rav.valueAggregate,
            amount
        );
    }

    /**
     * @dev Retrieves the amount of escrow deposited by a sender for a receiver.
     * @param sender Address of the sender.
     * @param receiver Address of the receiver.
     * @return The amount of escrow deposited.
     */
    function getEscrowAmount(
        address sender,
        address receiver
    ) external view returns (uint256) {
        return escrowAccounts[sender][receiver].balance;
    }

    /**
     * @dev Retrieves the escrow account details for a sender-receiver pair of the sender that a signer is authorized for.
     * @param signer Address of the authorized signer.
     * @param receiver Address of the receiver.
     * @return The escrow account details.
     */
    function getEscrowAccountFromSignerAddress(
        address signer,
        address receiver
    ) external view returns (EscrowAccount memory) {
        address sender = authorizedSigners[signer].sender;
        if (sender == address(0)) {
            revert SignerNotAuthorized();
        }
        return escrowAccounts[sender][receiver];
    }

    /**
     * @dev Verifies a proof that authorizes the sender to authorize the signer.
     * @param proof The proof provided by the signer to authorize the sender.
     * @param signer The address of the signer being authorized.
     * @notice REVERT with error:
     *               - InvalidSignerProof: If the given proof is not valid
     */
    function verifyAuthorizedSignerProof(
        bytes calldata proof,
        uint256 proofDeadline,
        address signer
    ) private view {
        // Verify that the proof deadline has not passed
        if (block.timestamp > proofDeadline) {
            revert InvalidSignerProof();
        }

        // Generate the hash of the sender's address
        bytes32 messageHash = keccak256(
            abi.encodePacked(block.chainid, proofDeadline, msg.sender)
        );

        // Generate the digest to be signed by the signer
        bytes32 digest = ECDSA.toEthSignedMessageHash(messageHash);

        // Verify that the recovered signer matches the expected signer
        if (ECDSA.recover(digest, proof) != signer) {
            revert InvalidSignerProof();
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @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 amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

    /**
     * @dev Moves `amount` 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 amount) 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 `amount` 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 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` 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 amount) external returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/extensions/IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (interfaces/IERC5267.sol)

pragma solidity ^0.8.0;

interface IERC5267 {
    /**
     * @dev MAY be emitted to signal that the domain could have changed.
     */
    event EIP712DomainChanged();

    /**
     * @dev returns the fields and values that describe the domain separator used by this contract for EIP-712
     * signature.
     */
    function eip712Domain()
        external
        view
        returns (
            bytes1 fields,
            string memory name,
            string memory version,
            uint256 chainId,
            address verifyingContract,
            bytes32 salt,
            uint256[] memory extensions
        );
}

// Copyright 2023-, Semiotic AI, Inc.
// SPDX-License-Identifier: Apache-2.0
pragma solidity 0.8.18;

/**
 * @title IStaking
 * @dev This interface is intended to mock the necessary functions of the `Staking` contract while using a
 *      version of solidity consistent with the project.
 * @notice When deploying this interface should be attached to the `Staking` contract.
 */
interface IStaking {
    struct Allocation {
        address indexer;
        bytes32 _subgraphDeploymentID;
        uint256 _tokens;
        address _allocationID;
        bytes32 _metadata;
    }
    function collect(uint256 _tokens, address _allocationID) external;
    function getAllocation(address _allocationID) external view returns (Allocation memory);
    function allocate(
        bytes32 _subgraphDeploymentID,
        uint256 _tokens,
        address _allocationID,
        bytes32 _metadata,
        bytes calldata _proof
    ) external;
    function stake(uint256 _tokens) external;
    function setAssetHolder(address _assetHolder, bool _allowed) external;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/math/Math.sol)

pragma solidity ^0.8.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    enum Rounding {
        Down, // Toward negative infinity
        Up, // Toward infinity
        Zero // Toward zero
    }

    /**
     * @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 up instead
     * of rounding down.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (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; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod0 := mul(x, y)
                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.
            require(denominator > prod1, "Math: mulDiv overflow");

            ///////////////////////////////////////////////
            // 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.

            // Does not overflow because the denominator cannot be zero at this stage in the function.
            uint256 twos = denominator & (~denominator + 1);
            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 (rounding == Rounding.Up && 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 down.
     *
     * 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 + (rounding == Rounding.Up && result * result < a ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 2, rounded down, of a positive value.
     * 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 + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 10, rounded down, of a positive value.
     * 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 + (rounding == Rounding.Up && 10 ** result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 256, rounded down, of a positive value.
     * 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 + (rounding == Rounding.Up && 1 << (result << 3) < value ? 1 : 0);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../extensions/IERC20Permit.sol";
import "../../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    /**
     * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    /**
     * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
     * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
     */
    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    /**
     * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 oldAllowance = token.allowance(address(this), spender);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance + value));
    }

    /**
     * @dev Decrease the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance - value));
        }
    }

    /**
     * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful. Compatible with tokens that require the approval to be set to
     * 0 before setting it to a non-zero value.
     */
    function forceApprove(IERC20 token, address spender, uint256 value) internal {
        bytes memory approvalCall = abi.encodeWithSelector(token.approve.selector, spender, value);

        if (!_callOptionalReturnBool(token, approvalCall)) {
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, 0));
            _callOptionalReturn(token, approvalCall);
        }
    }

    /**
     * @dev Use a ERC-2612 signature to set the `owner` approval toward `spender` on `token`.
     * Revert on invalid signature.
     */
    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address-functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        require(returndata.length == 0 || abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     *
     * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
     */
    function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We cannot use {Address-functionCall} here since this should return false
        // and not revert is the subcall reverts.

        (bool success, bytes memory returndata) = address(token).call(data);
        return
            success && (returndata.length == 0 || abi.decode(returndata, (bool))) && Address.isContract(address(token));
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/ShortStrings.sol)

pragma solidity ^0.8.8;

import "./StorageSlot.sol";

// | string  | 0xAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA   |
// | length  | 0x                                                              BB |
type ShortString is bytes32;

/**
 * @dev This library provides functions to convert short memory strings
 * into a `ShortString` type that can be used as an immutable variable.
 *
 * Strings of arbitrary length can be optimized using this library if
 * they are short enough (up to 31 bytes) by packing them with their
 * length (1 byte) in a single EVM word (32 bytes). Additionally, a
 * fallback mechanism can be used for every other case.
 *
 * Usage example:
 *
 * ```solidity
 * contract Named {
 *     using ShortStrings for *;
 *
 *     ShortString private immutable _name;
 *     string private _nameFallback;
 *
 *     constructor(string memory contractName) {
 *         _name = contractName.toShortStringWithFallback(_nameFallback);
 *     }
 *
 *     function name() external view returns (string memory) {
 *         return _name.toStringWithFallback(_nameFallback);
 *     }
 * }
 * ```
 */
library ShortStrings {
    // Used as an identifier for strings longer than 31 bytes.
    bytes32 private constant _FALLBACK_SENTINEL = 0x00000000000000000000000000000000000000000000000000000000000000FF;

    error StringTooLong(string str);
    error InvalidShortString();

    /**
     * @dev Encode a string of at most 31 chars into a `ShortString`.
     *
     * This will trigger a `StringTooLong` error is the input string is too long.
     */
    function toShortString(string memory str) internal pure returns (ShortString) {
        bytes memory bstr = bytes(str);
        if (bstr.length > 31) {
            revert StringTooLong(str);
        }
        return ShortString.wrap(bytes32(uint256(bytes32(bstr)) | bstr.length));
    }

    /**
     * @dev Decode a `ShortString` back to a "normal" string.
     */
    function toString(ShortString sstr) internal pure returns (string memory) {
        uint256 len = byteLength(sstr);
        // using `new string(len)` would work locally but is not memory safe.
        string memory str = new string(32);
        /// @solidity memory-safe-assembly
        assembly {
            mstore(str, len)
            mstore(add(str, 0x20), sstr)
        }
        return str;
    }

    /**
     * @dev Return the length of a `ShortString`.
     */
    function byteLength(ShortString sstr) internal pure returns (uint256) {
        uint256 result = uint256(ShortString.unwrap(sstr)) & 0xFF;
        if (result > 31) {
            revert InvalidShortString();
        }
        return result;
    }

    /**
     * @dev Encode a string into a `ShortString`, or write it to storage if it is too long.
     */
    function toShortStringWithFallback(string memory value, string storage store) internal returns (ShortString) {
        if (bytes(value).length < 32) {
            return toShortString(value);
        } else {
            StorageSlot.getStringSlot(store).value = value;
            return ShortString.wrap(_FALLBACK_SENTINEL);
        }
    }

    /**
     * @dev Decode a string that was encoded to `ShortString` or written to storage using {setWithFallback}.
     */
    function toStringWithFallback(ShortString value, string storage store) internal pure returns (string memory) {
        if (ShortString.unwrap(value) != _FALLBACK_SENTINEL) {
            return toString(value);
        } else {
            return store;
        }
    }

    /**
     * @dev Return the length of a string that was encoded to `ShortString` or written to storage using {setWithFallback}.
     *
     * WARNING: This will return the "byte length" of the string. This may not reflect the actual length in terms of
     * actual characters as the UTF-8 encoding of a single character can span over multiple bytes.
     */
    function byteLengthWithFallback(ShortString value, string storage store) internal view returns (uint256) {
        if (ShortString.unwrap(value) != _FALLBACK_SENTINEL) {
            return byteLength(value);
        } else {
            return bytes(store).length;
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/math/SignedMath.sol)

pragma solidity ^0.8.0;

/**
 * @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 v4.9.0) (utils/StorageSlot.sol)
// This file was procedurally generated from scripts/generate/templates/StorageSlot.js.

pragma solidity ^0.8.0;

/**
 * @dev Library for reading and writing primitive types to specific storage slots.
 *
 * Storage slots are often used to avoid storage conflict when dealing with upgradeable contracts.
 * This library helps with reading and writing to such slots without the need for inline assembly.
 *
 * The functions in this library return Slot structs that contain a `value` member that can be used to read or write.
 *
 * Example usage to set ERC1967 implementation slot:
 * ```solidity
 * contract ERC1967 {
 *     bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
 *
 *     function _getImplementation() internal view returns (address) {
 *         return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
 *     }
 *
 *     function _setImplementation(address newImplementation) internal {
 *         require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
 *         StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
 *     }
 * }
 * ```
 *
 * _Available since v4.1 for `address`, `bool`, `bytes32`, `uint256`._
 * _Available since v4.9 for `string`, `bytes`._
 */
library StorageSlot {
    struct AddressSlot {
        address value;
    }

    struct BooleanSlot {
        bool value;
    }

    struct Bytes32Slot {
        bytes32 value;
    }

    struct Uint256Slot {
        uint256 value;
    }

    struct StringSlot {
        string value;
    }

    struct BytesSlot {
        bytes value;
    }

    /**
     * @dev Returns an `AddressSlot` with member `value` located at `slot`.
     */
    function getAddressSlot(bytes32 slot) internal pure returns (AddressSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `BooleanSlot` with member `value` located at `slot`.
     */
    function getBooleanSlot(bytes32 slot) internal pure returns (BooleanSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `Bytes32Slot` with member `value` located at `slot`.
     */
    function getBytes32Slot(bytes32 slot) internal pure returns (Bytes32Slot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `Uint256Slot` with member `value` located at `slot`.
     */
    function getUint256Slot(bytes32 slot) internal pure returns (Uint256Slot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `StringSlot` with member `value` located at `slot`.
     */
    function getStringSlot(bytes32 slot) internal pure returns (StringSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `StringSlot` representation of the string storage pointer `store`.
     */
    function getStringSlot(string storage store) internal pure returns (StringSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := store.slot
        }
    }

    /**
     * @dev Returns an `BytesSlot` with member `value` located at `slot`.
     */
    function getBytesSlot(bytes32 slot) internal pure returns (BytesSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `BytesSlot` representation of the bytes storage pointer `store`.
     */
    function getBytesSlot(bytes storage store) internal pure returns (BytesSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := store.slot
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Strings.sol)

pragma solidity ^0.8.0;

import "./math/Math.sol";
import "./math/SignedMath.sol";

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

    /**
     * @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), _SYMBOLS))
                }
                value /= 10;
                if (value == 0) break;
            }
            return buffer;
        }
    }

    /**
     * @dev Converts a `int256` to its ASCII `string` decimal representation.
     */
    function toString(int256 value) internal pure returns (string memory) {
        return string(abi.encodePacked(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) {
        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] = _SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        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 keccak256(bytes(a)) == keccak256(bytes(b));
    }
}

// Copyright 2023-, Semiotic AI, Inc.
// SPDX-License-Identifier: Apache-2.0
pragma solidity 0.8.18;

import {ECDSA} from "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
import {EIP712} from "@openzeppelin/contracts/utils/cryptography/EIP712.sol";

/**
 * @title TAPVerifier
 * @dev A contract for verifying receipt aggregation vouchers.
 */
contract TAPVerifier is EIP712 {
    struct ReceiptAggregateVoucher {
        address allocationId;
        uint64 timestampNs;
        uint128 valueAggregate;
    }

    struct SignedRAV {
        ReceiptAggregateVoucher rav;
        bytes signature; // 65 bytes: r (32 Bytes) || s (32 Bytes) || v (1 Byte)
    }

    // --- EIP 712 ---
    bytes32 private constant RAV_TYPEHASH =
        keccak256(
            "ReceiptAggregateVoucher(address allocationId,uint64 timestampNs,uint128 valueAggregate)"
        );

    /**
     * @dev Constructs a new instance of the TAPVerifier contract.
     */
    constructor(string memory name, string memory version) EIP712(name, version) {}

    /**
     * @dev Recovers the signer address of a signed ReceiptAggregateVoucher (RAV).
     * @param signedRAV The SignedRAV containing the RAV and its signature.
     * @return The address of the signer.
     * @notice REVERT: This function may revert if ECDSA.recover fails, check ECDSA library for details.
     */
    function recoverRAVSigner(
        SignedRAV calldata signedRAV
    ) public view returns (address) {
        bytes32 messageHash = hashRAV(signedRAV.rav);
        return ECDSA.recover(messageHash, signedRAV.signature);
    }

    /**
     * @dev Compares address recovered from signature to provided address.
     * @param signedRAV The SignedRAV containing the RAV and its signature.
     * @param expectedAddress The address to compare the recovered address to.
     * @return True if the recovered address matches the provided address, false otherwise.
     * @notice REVERT: This function may revert if ECDSA.recover fails, check ECDSA library for details.
     */
    function verifyRAVSignature(
        SignedRAV calldata signedRAV,
        address expectedAddress
    ) external view returns (bool) {
        return recoverRAVSigner(signedRAV) == expectedAddress;
    }

    /**
     * @dev Computes the hash of a ReceiptAggregateVoucher (RAV).
     * @param rav The RAV for which to compute the hash.
     * @return The hash of the RAV.
     */
    function hashRAV(
        ReceiptAggregateVoucher calldata rav
    ) public view returns (bytes32) {
        return
            _hashTypedDataV4(
                keccak256(
                    abi.encode(
                        RAV_TYPEHASH,
                        rav.allocationId,
                        rav.timestampNs,
                        rav.valueAggregate
                    )
                )
            );
    }
}

{
  "compilationTarget": {
    "src/Escrow.sol": "Escrow"
  },
  "evmVersion": "paris",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": [
    ":@ensdomains/=lib/contracts/node_modules/@ensdomains/",
    ":@openzeppelin/=lib/openzeppelin-contracts/",
    ":arbos-precompiles/=lib/contracts/",
    ":ds-test/=lib/forge-std/lib/ds-test/src/",
    ":erc4626-tests/=lib/openzeppelin-contracts/lib/erc4626-tests/",
    ":eth-gas-reporter/=lib/contracts/node_modules/eth-gas-reporter/",
    ":forge-std/=lib/forge-std/src/",
    ":hardhat/=lib/contracts/node_modules/hardhat/",
    ":openzeppelin-contracts/=lib/openzeppelin-contracts/",
    ":openzeppelin/=lib/openzeppelin-contracts/contracts/",
    ":solmate/=lib/solmate/src/"
  ]
}