// File: @openzeppelin/contracts/access/Ownable.sol



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

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

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

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

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

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin/contracts/security/ReentrancyGuard.sol



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

pragma solidity ^0.8.0;

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

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

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be _NOT_ENTERED
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

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

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

    /**
     * @dev Returns true if the reentrancy guard is currently set to "entered", which indicates there is a
     * `nonReentrant` function in the call stack.
     */
    function _reentrancyGuardEntered() internal view returns (bool) {
        return _status == _ENTERED;
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// 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);
}

// File: @openzeppelin/contracts/token/ERC721/ERC721.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC721/ERC721.sol)

pragma solidity ^0.8.0;

import "./IERC721.sol";
import "./IERC721Receiver.sol";
import "./extensions/IERC721Metadata.sol";
import "../../utils/Address.sol";
import "../../utils/Context.sol";
import "../../utils/Strings.sol";
import "../../utils/introspection/ERC165.sol";

/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension, but not including the Enumerable extension, which is available separately as
 * {ERC721Enumerable}.
 */
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
    using Address for address;
    using Strings for uint256;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

    // Mapping from token ID to owner address
    mapping(uint256 => address) private _owners;

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

    // Mapping from token ID to approved address
    mapping(uint256 => address) private _tokenApprovals;

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

    /**
     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721-balanceOf}.
     */
    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), "ERC721: address zero is not a valid owner");
        return _balances[owner];
    }

    /**
     * @dev See {IERC721-ownerOf}.
     */
    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        address owner = _ownerOf(tokenId);
        require(owner != address(0), "ERC721: invalid token ID");
        return owner;
    }

    /**
     * @dev See {IERC721Metadata-name}.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev See {IERC721Metadata-symbol}.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        _requireMinted(tokenId);

        string memory baseURI = _baseURI();
        return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : "";
    }

    /**
     * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
     * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
     * by default, can be overridden in child contracts.
     */
    function _baseURI() internal view virtual returns (string memory) {
        return "";
    }

    /**
     * @dev See {IERC721-approve}.
     */
    function approve(address to, uint256 tokenId) public virtual override {
        address owner = ERC721.ownerOf(tokenId);
        require(to != owner, "ERC721: approval to current owner");

        require(
            _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
            "ERC721: approve caller is not token owner or approved for all"
        );

        _approve(to, tokenId);
    }

    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        _requireMinted(tokenId);

        return _tokenApprovals[tokenId];
    }

    /**
     * @dev See {IERC721-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        _setApprovalForAll(_msgSender(), operator, approved);
    }

    /**
     * @dev See {IERC721-isApprovedForAll}.
     */
    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[owner][operator];
    }

    /**
     * @dev See {IERC721-transferFrom}.
     */
    function transferFrom(address from, address to, uint256 tokenId) public virtual override {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner or approved");

        _transfer(from, to, tokenId);
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId) public virtual override {
        safeTransferFrom(from, to, tokenId, "");
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory data) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner or approved");
        _safeTransfer(from, to, tokenId, data);
    }

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * `data` is additional data, it has no specified format and it is sent in call to `to`.
     *
     * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
     * implement alternative mechanisms to perform token transfer, such as signature-based.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeTransfer(address from, address to, uint256 tokenId, bytes memory data) internal virtual {
        _transfer(from, to, tokenId);
        require(_checkOnERC721Received(from, to, tokenId, data), "ERC721: transfer to non ERC721Receiver implementer");
    }

    /**
     * @dev Returns the owner of the `tokenId`. Does NOT revert if token doesn't exist
     */
    function _ownerOf(uint256 tokenId) internal view virtual returns (address) {
        return _owners[tokenId];
    }

    /**
     * @dev Returns whether `tokenId` exists.
     *
     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
     *
     * Tokens start existing when they are minted (`_mint`),
     * and stop existing when they are burned (`_burn`).
     */
    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return _ownerOf(tokenId) != address(0);
    }

    /**
     * @dev Returns whether `spender` is allowed to manage `tokenId`.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
        address owner = ERC721.ownerOf(tokenId);
        return (spender == owner || isApprovedForAll(owner, spender) || getApproved(tokenId) == spender);
    }

    /**
     * @dev Safely mints `tokenId` and transfers it to `to`.
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeMint(address to, uint256 tokenId) internal virtual {
        _safeMint(to, tokenId, "");
    }

    /**
     * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
     * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
     */
    function _safeMint(address to, uint256 tokenId, bytes memory data) internal virtual {
        _mint(to, tokenId);
        require(
            _checkOnERC721Received(address(0), to, tokenId, data),
            "ERC721: transfer to non ERC721Receiver implementer"
        );
    }

    /**
     * @dev Mints `tokenId` and transfers it to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - `to` cannot be the zero address.
     *
     * Emits a {Transfer} event.
     */
    function _mint(address to, uint256 tokenId) internal virtual {
        require(to != address(0), "ERC721: mint to the zero address");
        require(!_exists(tokenId), "ERC721: token already minted");

        _beforeTokenTransfer(address(0), to, tokenId, 1);

        // Check that tokenId was not minted by `_beforeTokenTransfer` hook
        require(!_exists(tokenId), "ERC721: token already minted");

        unchecked {
            // Will not overflow unless all 2**256 token ids are minted to the same owner.
            // Given that tokens are minted one by one, it is impossible in practice that
            // this ever happens. Might change if we allow batch minting.
            // The ERC fails to describe this case.
            _balances[to] += 1;
        }

        _owners[tokenId] = to;

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

        _afterTokenTransfer(address(0), to, tokenId, 1);
    }

    /**
     * @dev Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     * This is an internal function that does not check if the sender is authorized to operate on the token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId) internal virtual {
        address owner = ERC721.ownerOf(tokenId);

        _beforeTokenTransfer(owner, address(0), tokenId, 1);

        // Update ownership in case tokenId was transferred by `_beforeTokenTransfer` hook
        owner = ERC721.ownerOf(tokenId);

        // Clear approvals
        delete _tokenApprovals[tokenId];

        unchecked {
            // Cannot overflow, as that would require more tokens to be burned/transferred
            // out than the owner initially received through minting and transferring in.
            _balances[owner] -= 1;
        }
        delete _owners[tokenId];

        emit Transfer(owner, address(0), tokenId);

        _afterTokenTransfer(owner, address(0), tokenId, 1);
    }

    /**
     * @dev Transfers `tokenId` from `from` to `to`.
     *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     *
     * Emits a {Transfer} event.
     */
    function _transfer(address from, address to, uint256 tokenId) internal virtual {
        require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer from incorrect owner");
        require(to != address(0), "ERC721: transfer to the zero address");

        _beforeTokenTransfer(from, to, tokenId, 1);

        // Check that tokenId was not transferred by `_beforeTokenTransfer` hook
        require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer from incorrect owner");

        // Clear approvals from the previous owner
        delete _tokenApprovals[tokenId];

        unchecked {
            // `_balances[from]` cannot overflow for the same reason as described in `_burn`:
            // `from`'s balance is the number of token held, which is at least one before the current
            // transfer.
            // `_balances[to]` could overflow in the conditions described in `_mint`. That would require
            // all 2**256 token ids to be minted, which in practice is impossible.
            _balances[from] -= 1;
            _balances[to] += 1;
        }
        _owners[tokenId] = to;

        emit Transfer(from, to, tokenId);

        _afterTokenTransfer(from, to, tokenId, 1);
    }

    /**
     * @dev Approve `to` to operate on `tokenId`
     *
     * Emits an {Approval} event.
     */
    function _approve(address to, uint256 tokenId) internal virtual {
        _tokenApprovals[tokenId] = to;
        emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
    }

    /**
     * @dev Approve `operator` to operate on all of `owner` tokens
     *
     * Emits an {ApprovalForAll} event.
     */
    function _setApprovalForAll(address owner, address operator, bool approved) internal virtual {
        require(owner != operator, "ERC721: approve to caller");
        _operatorApprovals[owner][operator] = approved;
        emit ApprovalForAll(owner, operator, approved);
    }

    /**
     * @dev Reverts if the `tokenId` has not been minted yet.
     */
    function _requireMinted(uint256 tokenId) internal view virtual {
        require(_exists(tokenId), "ERC721: invalid token ID");
    }

    /**
     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
     * The call is not executed if the target address is not a contract.
     *
     * @param from address representing the previous owner of the given token ID
     * @param to target address that will receive the tokens
     * @param tokenId uint256 ID of the token to be transferred
     * @param data bytes optional data to send along with the call
     * @return bool whether the call correctly returned the expected magic value
     */
    function _checkOnERC721Received(
        address from,
        address to,
        uint256 tokenId,
        bytes memory data
    ) private returns (bool) {
        if (to.isContract()) {
            try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, data) returns (bytes4 retval) {
                return retval == IERC721Receiver.onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert("ERC721: transfer to non ERC721Receiver implementer");
                } else {
                    /// @solidity memory-safe-assembly
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            return true;
        }
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting and burning. If {ERC721Consecutive} is
     * used, the hook may be called as part of a consecutive (batch) mint, as indicated by `batchSize` greater than 1.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s tokens will be transferred to `to`.
     * - When `from` is zero, the tokens will be minted for `to`.
     * - When `to` is zero, ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     * - `batchSize` is non-zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 firstTokenId, uint256 batchSize) internal virtual {}

    /**
     * @dev Hook that is called after any token transfer. This includes minting and burning. If {ERC721Consecutive} is
     * used, the hook may be called as part of a consecutive (batch) mint, as indicated by `batchSize` greater than 1.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s tokens were transferred to `to`.
     * - When `from` is zero, the tokens were minted for `to`.
     * - When `to` is zero, ``from``'s tokens were burned.
     * - `from` and `to` are never both zero.
     * - `batchSize` is non-zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(address from, address to, uint256 firstTokenId, uint256 batchSize) internal virtual {}

    /**
     * @dev Unsafe write access to the balances, used by extensions that "mint" tokens using an {ownerOf} override.
     *
     * WARNING: Anyone calling this MUST ensure that the balances remain consistent with the ownership. The invariant
     * being that for any address `a` the value returned by `balanceOf(a)` must be equal to the number of tokens such
     * that `ownerOf(tokenId)` is `a`.
     */
    // solhint-disable-next-line func-name-mixedcase
    function __unsafe_increaseBalance(address account, uint256 amount) internal {
        _balances[account] += amount;
    }
}

// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC721.sol";

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

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

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

// File: @openzeppelin/contracts/token/ERC721/IERC721.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

import "../../utils/introspection/IERC165.sol";

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

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

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

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

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

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

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

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

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

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

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

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

// File: @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

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

// File: @openzeppelin/contracts/utils/Address.sol



// 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);
        }
    }
}

// File: @openzeppelin/contracts/utils/Context.sol



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

pragma solidity ^0.8.0;

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

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

// File: @openzeppelin/contracts/utils/introspection/ERC165.sol



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

pragma solidity ^0.8.0;

import "./IERC165.sol";

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

// File: @openzeppelin/contracts/utils/introspection/IERC165.sol



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

pragma solidity ^0.8.0;

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

// File: @openzeppelin/contracts/utils/math/Math.sol



// 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);
        }
    }
}

// File: @openzeppelin/contracts/utils/math/SignedMath.sol



// 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);
        }
    }
}

// File: @openzeppelin/contracts/utils/Strings.sol



// 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));
    }
}

// File: contracts/common/EIP712.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

contract EIP712 {
    // --- Public fields ---

    bytes32 public immutable DOMAIN_SEPARATOR;

    // --- Constructor ---

    constructor(bytes memory name, bytes memory version) {
        uint256 chainId;
        assembly {
            chainId := chainid()
        }

        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                keccak256(
                    "EIP712Domain("
                    "string name,"
                    "string version,"
                    "uint256 chainId,"
                    "address verifyingContract"
                    ")"
                ),
                keccak256(name),
                keccak256(version),
                chainId,
                address(this)
            )
        );
    }

    // --- Internal methods ---

    /**
     * @dev Get the EIP712 hash of a struct hash
     *
     * @param structHash Struct hash to get the EIP712 hash for
     *
     * @return eip712Hash The resulting EIP712 hash
     */
    function _getEIP712Hash(
        bytes32 structHash
    ) internal view returns (bytes32 eip712Hash) {
        eip712Hash = keccak256(
            abi.encodePacked(hex"1901", DOMAIN_SEPARATOR, structHash)
        );
    }
}

// File: contracts/common/interfaces/IEIP2612.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

interface IEIP2612 {
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;
}

// File: contracts/common/interfaces/IPermit2.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

interface IPermit2 {
    event Permit(
        address indexed owner,
        address indexed token,
        address indexed spender,
        uint160 amount,
        uint48 expiration,
        uint48 nonce
    );

    struct PermitDetails {
        address token;
        uint160 amount;
        uint48 expiration;
        uint48 nonce;
    }

    struct PermitSingle {
        PermitDetails details;
        address spender;
        uint256 sigDeadline;
    }

    function permit(
        address owner,
        PermitSingle memory permitSingle,
        bytes calldata signature
    ) external;

    function transferFrom(
        address from,
        address to,
        uint160 amount,
        address token
    ) external;
}

// File: contracts/common/PermitExecutor.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

import {IPermit2} from "./interfaces/IPermit2.sol";
import {IEIP2612} from "./interfaces/IEIP2612.sol";

contract PermitExecutor {
    // --- Structs and enums ---

    enum Kind {
        EIP2612,
        PERMIT2
    }

    struct Permit {
        Kind kind;
        bytes data;
    }

    // --- Public fields ---

    address public immutable permit2 =
        0x000000000022D473030F116dDEE9F6B43aC78BA3;

    // --- Modifiers ---

    /**
     * @dev Execute permits
     *
     * @param permits Permits to execute
     */
    modifier executePermits(Permit[] calldata permits) {
        unchecked {
            uint256 permitsLength = permits.length;
            for (uint256 i; i < permitsLength; i++) {
                Permit calldata permit = permits[i];
                if (permit.kind == Kind.EIP2612) {
                    (
                        address token,
                        address owner,
                        address spender,
                        uint256 value,
                        uint256 deadline,
                        uint8 v,
                        bytes32 r,
                        bytes32 s
                    ) = abi.decode(
                            permit.data,
                            (
                                address,
                                address,
                                address,
                                uint256,
                                uint256,
                                uint8,
                                bytes32,
                                bytes32
                            )
                        );

                    IEIP2612(token).permit(
                        owner,
                        spender,
                        value,
                        deadline,
                        v,
                        r,
                        s
                    );
                } else {
                    (
                        address owner,
                        IPermit2.PermitSingle memory permitSingle,
                        bytes memory signature
                    ) = abi.decode(
                            permit.data,
                            (address, IPermit2.PermitSingle, bytes)
                        );

                    IPermit2(permit2).permit(owner, permitSingle, signature);
                }
            }
        }

        _;
    }

    // --- Internal methods ---

    function _permit2TransferFrom(
        address from,
        address to,
        uint160 amount,
        address token
    ) internal {
        IPermit2(permit2).transferFrom(from, to, amount, token);
    }
}

// File: contracts/common/SignatureVerification.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

import {EIP712} from "./EIP712.sol";

// Copied from Seaport's source code
abstract contract SignatureVerification is EIP712 {
    // --- Errors ---

    error InvalidSignature();

    // --- Virtual methods ---

    function _lookupBulkOrderTypehash(
        uint256 treeHeight
    ) internal pure virtual returns (bytes32 typeHash);

    // --- Internal methods ---

    function _verifySignature(
        bytes32 intentHash,
        address signer,
        bytes memory signature
    ) internal view {
        // Skip signature verification if the signer is the caller
        if (signer == msg.sender) {
            return;
        }

        bytes32 originalDigest = _getEIP712Hash(intentHash);
        uint256 originalSignatureLength = signature.length;

        bytes32 digest;
        if (_isValidBulkOrderSize(originalSignatureLength)) {
            (intentHash) = _computeBulkOrderProof(signature, intentHash);
            digest = _getEIP712Hash(intentHash);
        } else {
            digest = originalDigest;
        }

        _assertValidSignature(
            signer,
            digest,
            originalDigest,
            originalSignatureLength,
            signature
        );
    }

    function _isValidBulkOrderSize(
        uint256 signatureLength
    ) internal pure returns (bool validLength) {
        // Utilize assembly to validate the length:
        // (64 + x) + 3 + 32y where (0 <= x <= 1) and (1 <= y <= 24)
        assembly {
            validLength := and(
                lt(sub(signatureLength, 0x63), 0x2e2),
                lt(and(add(signatureLength, 0x1d), 0x1f), 0x2)
            )
        }
    }

    function _computeBulkOrderProof(
        bytes memory proofAndSignature,
        bytes32 leaf
    ) internal pure returns (bytes32 bulkOrderHash) {
        // Declare arguments for the root hash and the height of the proof
        bytes32 root;
        uint256 height;

        // Utilize assembly to efficiently derive the root hash using the proof
        assembly {
            // Retrieve the length of the proof, key, and signature combined
            let fullLength := mload(proofAndSignature)

            // If proofAndSignature has odd length, it is a compact signature with 64 bytes
            let signatureLength := sub(65, and(fullLength, 1))

            // Derive height (or depth of tree) with signature and proof length
            height := shr(0x5, sub(fullLength, signatureLength))

            // Update the length in memory to only include the signature
            mstore(proofAndSignature, signatureLength)

            // Derive the pointer for the key using the signature length
            let keyPtr := add(proofAndSignature, add(0x20, signatureLength))

            // Retrieve the three-byte key using the derived pointer
            let key := shr(0xe8, mload(keyPtr))

            // Retrieve pointer to first proof element by applying a constant for the key size to the derived key pointer
            let proof := add(keyPtr, 0x3)

            // Compute level 1
            let scratchPtr1 := shl(0x5, and(key, 1))
            mstore(scratchPtr1, leaf)
            mstore(xor(scratchPtr1, 0x20), mload(proof))

            // Compute remaining proofs
            for {
                let i := 1
            } lt(i, height) {
                i := add(i, 1)
            } {
                proof := add(proof, 0x20)
                let scratchPtr := shl(0x5, and(shr(i, key), 1))
                mstore(scratchPtr, keccak256(0, 0x40))
                mstore(xor(scratchPtr, 0x20), mload(proof))
            }

            // Compute root hash
            root := keccak256(0, 0x40)
        }

        // Retrieve appropriate typehash constant based on height.
        bytes32 rootTypeHash = _lookupBulkOrderTypehash(height);

        // Use the typehash and the root hash to derive final bulk order hash
        assembly {
            mstore(0, rootTypeHash)
            mstore(0x20, root)
            bulkOrderHash := keccak256(0, 0x40)
        }
    }

    function _assertValidSignature(
        address signer,
        bytes32 digest,
        bytes32 originalDigest,
        uint256 originalSignatureLength,
        bytes memory signature
    ) internal view {
        // Declare value for ecrecover equality or 1271 call success status
        bool success;

        // Utilize assembly to perform optimized signature verification check
        assembly {
            // Ensure that first word of scratch space is empty
            mstore(0, 0)

            // Get the length of the signature.
            let signatureLength := mload(signature)

            // Get the pointer to the value preceding the signature length
            // This will be used for temporary memory overrides - either the signature head for isValidSignature or the digest for ecrecover
            let wordBeforeSignaturePtr := sub(signature, 0x20)

            // Cache the current value behind the signature to restore it later
            let cachedWordBeforeSignature := mload(wordBeforeSignaturePtr)

            // Declare lenDiff + recoveredSigner scope to manage stack pressure
            {
                // Take the difference between the max ECDSA signature length and the actual signature length (overflow desired for any values > 65)
                // If the diff is not 0 or 1, it is not a valid ECDSA signature - move on to EIP1271 check
                let lenDiff := sub(65, signatureLength)

                // Declare variable for recovered signer
                let recoveredSigner

                // If diff is 0 or 1, it may be an ECDSA signature
                // Try to recover signer
                if iszero(gt(lenDiff, 1)) {
                    // Read the signature `s` value
                    let originalSignatureS := mload(add(signature, 0x40))

                    // Read the first byte of the word after `s`
                    // If the signature is 65 bytes, this will be the real `v` value
                    // If not, it will need to be modified - doing it this way saves an extra condition.
                    let v := byte(0, mload(add(signature, 0x60)))

                    // If lenDiff is 1, parse 64-byte signature as ECDSA
                    if lenDiff {
                        // Extract yParity from highest bit of vs and add 27 to get v
                        v := add(shr(0xff, originalSignatureS), 27)

                        // Extract canonical s from vs, all but the highest bit
                        // Temporarily overwrite the original `s` value in the signature
                        mstore(
                            add(signature, 0x40),
                            and(
                                originalSignatureS,
                                0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
                            )
                        )
                    }
                    // Temporarily overwrite the signature length with `v` to conform to the expected input for ecrecover
                    mstore(signature, v)

                    // Temporarily overwrite the word before the length with `digest` to conform to the expected input for ecrecover
                    mstore(wordBeforeSignaturePtr, digest)

                    // Attempt to recover the signer for the given signature
                    // Do not check the call status as ecrecover will return a null address if the signature is invalid
                    pop(
                        staticcall(
                            gas(),
                            0x1, // Call ecrecover precompile
                            wordBeforeSignaturePtr, // Use data memory location
                            0x80, // Size of digest, v, r, and s
                            0, // Write result to scratch space
                            0x20 // Provide size of returned result
                        )
                    )

                    // Restore cached word before signature
                    mstore(wordBeforeSignaturePtr, cachedWordBeforeSignature)

                    // Restore cached signature length
                    mstore(signature, signatureLength)

                    // Restore cached signature `s` value
                    mstore(add(signature, 0x40), originalSignatureS)

                    // Read the recovered signer from the buffer given as return space for ecrecover
                    recoveredSigner := mload(0)
                }

                // Set success to true if the signature provided was a valid
                // ECDSA signature and the signer is not the null address
                // Use gt instead of direct as success is used outside of assembly
                success := and(eq(signer, recoveredSigner), gt(signer, 0))
            }

            // If the signature was not verified with ecrecover, try EIP1271
            if iszero(success) {
                // Reset the original signature length
                mstore(signature, originalSignatureLength)

                // Temporarily overwrite the word before the signature length and use it as the
                // head of the signature input to `isValidSignature`, which has a value of 64
                mstore(wordBeforeSignaturePtr, 0x40)

                // Get pointer to use for the selector of `isValidSignature`
                let selectorPtr := sub(signature, 0x44)

                // Cache the value currently stored at the selector pointer
                let cachedWordOverwrittenBySelector := mload(selectorPtr)

                // Cache the value currently stored at the digest pointer
                let cachedWordOverwrittenByDigest := mload(sub(signature, 0x40))

                // Write the selector first, since it overlaps the digest
                mstore(selectorPtr, 0x44)

                // Next, write the original digest
                mstore(sub(signature, 0x40), originalDigest)

                // Call signer with `isValidSignature` to validate signature
                success := staticcall(
                    gas(),
                    signer,
                    selectorPtr,
                    add(originalSignatureLength, 0x64),
                    0,
                    0x20
                )

                // Determine if the signature is valid on successful calls
                if success {
                    // If first word of scratch space does not contain EIP-1271 signature selector, revert
                    if iszero(
                        eq(
                            mload(0),
                            0x1626ba7e00000000000000000000000000000000000000000000000000000000
                        )
                    ) {
                        success := 0
                    }
                }

                // Restore the cached values overwritten by selector, digest and signature head
                mstore(wordBeforeSignaturePtr, cachedWordBeforeSignature)
                mstore(selectorPtr, cachedWordOverwrittenBySelector)
                mstore(sub(signature, 0x40), cachedWordOverwrittenByDigest)
            }
        }

        if (!success) {
            revert InvalidSignature();
        }
    }
}

// File: contracts/erc20/interfaces/ISolutionERC20.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

import {MemswapERC20} from "../MemswapERC20.sol";

interface ISolutionERC20 {
    function callback(
        MemswapERC20.Intent memory intent,
        uint128 amountToFill,
        bytes memory data
    ) external;

    function refund() external payable;
}

// File: contracts/erc20/MemswapERC20.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

import {EIP712} from "../common/EIP712.sol";
import {PermitExecutor} from "../common/PermitExecutor.sol";
import {SignatureVerification} from "../common/SignatureVerification.sol";
import {MemswapAlphaNFT} from "../nft/MemswapAlphaNFT.sol";

import {ISolutionERC20} from "./interfaces/ISolutionERC20.sol";

contract MemswapERC20 is
    Ownable,
    PermitExecutor,
    ReentrancyGuard,
    SignatureVerification
{
    // --- Structs and enums ---

    struct Intent {
        // When isBuy = true:
        // amount = buy amount
        // endAmount = sell end amount
        // startAmountBps = sell start amount bps
        // expectedAmountBps = sell expected amount bps

        // When isBuy = false:
        // amount = sell amount
        // endAmount = buy end amount
        // startAmountBps = buy start amount bps
        // expectedAmountBps = buy expected amount bps

        // Exact output (isBuy = true) or exact input (isBuy = false)
        bool isBuy;
        address buyToken;
        address sellToken;
        address maker;
        // The address allowed to solve or authorize others to solve
        address solver;
        address source;
        uint16 feeBps;
        uint16 surplusBps;
        uint32 startTime;
        uint32 endTime;
        bool isPartiallyFillable;
        bool isSmartOrder;
        bool isIncentivized;
        uint128 amount;
        uint128 endAmount;
        uint16 startAmountBps;
        uint16 expectedAmountBps;
        bytes signature;
    }

    struct IntentStatus {
        bool isPrevalidated;
        bool isCancelled;
        uint128 amountFilled;
    }

    struct Authorization {
        // When isBuy = true:
        // fillAmountToCheck = buy amount to fill
        // executeAmountToCheck = maximum sell amount pulled from user

        // When isBuy = false:
        // fillAmountToCheck = sell amount to fill
        // executeAmountToCheck = minimum buy amount pushed to user

        uint128 fillAmountToCheck;
        uint128 executeAmountToCheck;
        uint32 blockDeadline;
    }

    struct Solution {
        // When isBuy = true:
        // fillAmount = buy amount to fill

        // When isBuy = false:
        // fillAmount = sell amount to fill

        bytes data;
        uint128 fillAmount;
    }

    // --- Events ---

    event IncentivizationParametersUpdated();
    event IntentCancelled(bytes32 indexed intentHash);
    event IntentPrevalidated(bytes32 indexed intentHash);
    event IntentSolved(
        bytes32 indexed intentHash,
        bool isBuy,
        address buyToken,
        address sellToken,
        address maker,
        address solver,
        uint128 buyAmount,
        uint128 sellAmount
    );
    event IntentsPosted();
    event NonceIncremented(address maker, uint256 newNonce);

    // --- Errors ---

    error AmountCheckFailed();
    error AuthorizationAmountMismatch();
    error AuthorizationIsExpired();
    error IntentCannotBePrevalidated();
    error IntentIsCancelled();
    error IntentIsExpired();
    error IntentIsFilled();
    error IntentIsNotPartiallyFillable();
    error IntentIsNotStarted();
    error InvalidFillAmount();
    error InvalidPriorityFee();
    error InvalidSolution();
    error InvalidStartAndEndTimes();
    error InvalidTip();
    error MerkleTreeTooLarge();
    error Unauthorized();
    error UnsuccessfulCall();

    // --- Fields ---

    bytes32 public immutable AUTHORIZATION_TYPEHASH;
    bytes32 public immutable INTENT_TYPEHASH;
    address public immutable MEMSWAP_ALPHA_NFT;

    mapping(address => uint256) public nonce;
    mapping(bytes32 => bytes32) public intentPrivateData;
    mapping(bytes32 => IntentStatus) public intentStatus;
    mapping(bytes32 => Authorization) public authorization;

    // Relevant for incentivized intents
    uint16 public defaultSlippage;
    uint16 public multiplier;
    uint64 public requiredPriorityFee;
    uint64 public minTip;
    uint64 public maxTip;

    // --- Constructor ---

    constructor(address memswapAlphaNft) EIP712("MemswapERC20", "1.0") {
        AUTHORIZATION_TYPEHASH = keccak256(
            abi.encodePacked(
                "Authorization(",
                "bytes32 intentHash,",
                "address solver,",
                "uint128 fillAmountToCheck,",
                "uint128 executeAmountToCheck,",
                "uint32 blockDeadline",
                ")"
            )
        );

        INTENT_TYPEHASH = keccak256(
            abi.encodePacked(
                "Intent(",
                "bool isBuy,",
                "address buyToken,",
                "address sellToken,",
                "address maker,",
                "address solver,",
                "address source,",
                "uint16 feeBps,",
                "uint16 surplusBps,",
                "uint32 startTime,",
                "uint32 endTime,",
                "uint256 nonce,",
                "bool isPartiallyFillable,",
                "bool isSmartOrder,",
                "bool isIncentivized,",
                "uint128 amount,",
                "uint128 endAmount,",
                "uint16 startAmountBps,",
                "uint16 expectedAmountBps",
                ")"
            )
        );

        MEMSWAP_ALPHA_NFT = memswapAlphaNft;

        defaultSlippage = 50;
        multiplier = 4;
        requiredPriorityFee = 1 gwei;
        minTip = 0.05 gwei * 500000;
        maxTip = 1.5 gwei * 500000;
    }

    // Fallback

    receive() external payable {}

    // Owner methods

    function updateIncentivizationParameters(
        uint16 newDefaultSlippage,
        uint16 newMultiplier,
        uint64 newRequiredPriorityFee,
        uint64 newMinTip,
        uint64 newMaxTip
    ) external onlyOwner {
        defaultSlippage = newDefaultSlippage;
        multiplier = newMultiplier;
        requiredPriorityFee = newRequiredPriorityFee;
        minTip = newMinTip;
        maxTip = newMaxTip;

        emit IncentivizationParametersUpdated();
    }

    // Public methods

    /**
     * @notice Authorize an address to solve particular intents
     *
     * @param intents Intents to solve
     * @param auths Authorizations
     * @param solver The address authorized to solve
     */
    function authorize(
        Intent[] calldata intents,
        Authorization[] calldata auths,
        address solver
    ) external {
        unchecked {
            uint256 intentsLength = intents.length;
            for (uint256 i; i < intentsLength; i++) {
                Intent calldata intent = intents[i];
                Authorization calldata auth = auths[i];

                if (intent.solver != msg.sender) {
                    revert Unauthorized();
                }

                bytes32 intentHash = getIntentHash(intent);
                bytes32 authId = keccak256(
                    abi.encodePacked(intentHash, solver)
                );
                authorization[authId] = auth;
            }
        }
    }

    /**
     * @notice Make intents available on-chain (this method doesn't do anything
     *         useful - it's only used as a mechanism for intent distribution)
     *
     * @custom:param intents Intents being made available
     */
    function post(
        /**
         * @custom:name intents
         */
        Intent[] calldata
    ) external {
        emit IntentsPosted();
    }

    /**
     * @notice Pre-validate an arbitrary number of intents (the signature of each
     *         intent will be checked, thus resulting in skipping verification on
     *         further attempts to solve the intent, unless the intent explicitly
     *         enforces checking the signature on every fill)
     *
     * @param intents Intents to validate
     */
    function prevalidate(Intent[] calldata intents) external {
        unchecked {
            uint256 intentsLength = intents.length;
            for (uint256 i; i < intentsLength; i++) {
                Intent calldata intent = intents[i];
                if (intent.isSmartOrder) {
                    revert IntentCannotBePrevalidated();
                }

                bytes32 intentHash = getIntentHash(intent);

                _prevalidateIntent(
                    intentHash,
                    intent.maker,
                    intent.isSmartOrder,
                    intent.signature
                );
                emit IntentPrevalidated(intentHash);
            }
        }
    }

    /**
     * @notice Cancel an arbitrary number of intents
     *
     * @param intents Intents to cancel
     */
    function cancel(Intent[] calldata intents) external {
        unchecked {
            uint256 intentsLength = intents.length;
            for (uint256 i; i < intentsLength; i++) {
                Intent calldata intent = intents[i];
                if (intent.maker != msg.sender) {
                    revert Unauthorized();
                }

                bytes32 intentHash = getIntentHash(intent);
                IntentStatus memory status = intentStatus[intentHash];
                status.isPrevalidated = false;
                status.isCancelled = true;

                intentStatus[intentHash] = status;
                emit IntentCancelled(intentHash);
            }
        }
    }

    /**
     * @notice Increment the nonce for `msg.sender`. This will result in
     *         the invalidation of any intents signed with a lower nonce
     *         than the latest value.
     */
    function incrementNonce() external {
        unchecked {
            uint256 newNonce = nonce[msg.sender] + 1;
            nonce[msg.sender] = newNonce;
            emit NonceIncremented(msg.sender, newNonce);
        }
    }

    /**
     * @notice Reveal intents by making available data assumed to not be publicly
     *         available (maker + signature prefix). This method should be called
     *         right before the solution transaction, ideally bundled, so that no
     *         details are revealed sooner than it should be.
     *
     * @param intents Intents to reveal
     */
    function reveal(Intent[] memory intents) external {
        unchecked {
            uint256 intentsLength = intents.length;
            for (uint256 i; i < intentsLength; i++) {
                Intent memory intent = intents[i];

                // Ensure the intent is valid
                bytes32 intentHash = getIntentHash(intent);
                _verifySignature(intentHash, intent.maker, intent.signature);

                // Extract the private data (intent + signature prefix)
                address maker = intent.maker;
                bytes12 signaturePrefix = bytes12(intent.signature);

                // Override the maker with the zero address to get the correct partial intent hash
                intent.maker = address(0);

                // Store the private data (intent + signature prefix)
                bytes32 partialIntentHash = getIntentHash(intent);
                intentPrivateData[partialIntentHash] = bytes32(
                    abi.encodePacked(maker, signaturePrefix)
                );
            }
        }
    }

    /**
     * @notice Solve intent
     *
     * @param intent Intent to solve
     * @param solution Solution
     * @param permits Permits to execute prior to the solution
     */
    function solve(
        Intent memory intent,
        Solution calldata solution,
        PermitExecutor.Permit[] calldata permits
    ) external payable nonReentrant executePermits(permits) {
        // Make any private data available
        _includePrivateData(intent);

        // Check authorization
        if (intent.solver != address(0) && intent.solver != msg.sender) {
            revert Unauthorized();
        }

        // Solve
        _solve(intent, solution, intent.isBuy ? type(uint128).max : 0);
    }

    /**
     * @notice Solve intent with authorization. Compared to the regular `solve`,
     *         this method allows solving intents of a different solver, as long
     *         as there's a valid authorization in-place for the current caller.
     *         The authorization will be checked via a storage slot.
     *
     * @param intent Intent to solve
     * @param solution Solution
     * @param permits Permits to execute prior to the solution
     */
    function solveWithOnChainAuthorizationCheck(
        Intent memory intent,
        Solution calldata solution,
        PermitExecutor.Permit[] calldata permits
    ) external payable nonReentrant executePermits(permits) {
        // Make any private data available
        _includePrivateData(intent);

        // Check authorization
        bytes32 intentHash = getIntentHash(intent);
        bytes32 authId = keccak256(abi.encodePacked(intentHash, msg.sender));
        Authorization memory auth = authorization[authId];
        _checkAuthorization(auth, solution.fillAmount);

        // Solve
        _solve(intent, solution, auth.executeAmountToCheck);
    }

    /**
     * @notice Solve intent with authorization. Compared to the regular `solve`,
     *         this method allows solving intents of a different solver, as long
     *         as there's a valid authorization in-place for the current caller.
     *         The authorization will be checked via a signature.
     *
     * @param intent Intent to solve
     * @param solution Solution for the intent
     * @param auth Authorization
     * @param authSignature Authorization signature
     * @param permits Permits to execute prior to the solution
     */
    function solveWithSignatureAuthorizationCheck(
        Intent memory intent,
        Solution calldata solution,
        Authorization calldata auth,
        bytes calldata authSignature,
        PermitExecutor.Permit[] calldata permits
    ) external payable nonReentrant executePermits(permits) {
        // Make any private data available
        _includePrivateData(intent);

        // Check authorization
        bytes32 intentHash = getIntentHash(intent);
        bytes32 authorizationHash = getAuthorizationHash(
            intentHash,
            msg.sender,
            auth
        );
        bytes32 digest = _getEIP712Hash(authorizationHash);
        _assertValidSignature(
            intent.solver,
            digest,
            digest,
            authSignature.length,
            authSignature
        );
        _checkAuthorization(auth, solution.fillAmount);

        // Solve
        _solve(intent, solution, auth.executeAmountToCheck);
    }

    // View methods

    /**
     * @notice Get the EIP712 struct hash for an authorization
     *
     * @param intentHash Intent EIP712 struct hash to authorize
     * @param solver Solver to authorize
     * @param auth Authorization details/conditions
     *
     * @return authorizationHash The EIP712 struct hash of the authorization
     */
    function getAuthorizationHash(
        bytes32 intentHash,
        address solver,
        Authorization memory auth
    ) public view returns (bytes32 authorizationHash) {
        authorizationHash = keccak256(
            abi.encode(
                AUTHORIZATION_TYPEHASH,
                intentHash,
                solver,
                auth.fillAmountToCheck,
                auth.executeAmountToCheck,
                auth.blockDeadline
            )
        );
    }

    /**
     * @notice Get the EIP712 struct hash for an intent
     *
     * @param intent Intent to compute the hash for
     *
     * @return intentHash The EIP712 struct hash of the intent
     */
    function getIntentHash(
        Intent memory intent
    ) public view returns (bytes32 intentHash) {
        intentHash = keccak256(
            bytes.concat(
                abi.encode(
                    INTENT_TYPEHASH,
                    intent.isBuy,
                    intent.buyToken,
                    intent.sellToken,
                    intent.maker,
                    intent.solver,
                    intent.source,
                    intent.feeBps,
                    intent.surplusBps,
                    intent.startTime,
                    intent.endTime,
                    nonce[intent.maker]
                ),
                abi.encode(
                    intent.isPartiallyFillable,
                    intent.isSmartOrder,
                    intent.isIncentivized,
                    intent.amount,
                    intent.endAmount,
                    intent.startAmountBps,
                    intent.expectedAmountBps
                )
            )
        );
    }

    // Internal methods

    function _preProcess(
        Intent memory intent,
        uint128 amountToFill
    ) internal returns (uint128 actualAmountToFill) {
        bytes32 intentHash = getIntentHash(intent);

        // Verify start and end times

        if (intent.startTime > block.timestamp) {
            revert IntentIsNotStarted();
        }

        if (intent.endTime < block.timestamp) {
            revert IntentIsExpired();
        }

        if (intent.startTime >= intent.endTime) {
            revert InvalidStartAndEndTimes();
        }

        // Verify cancellation status and signature

        IntentStatus memory status = intentStatus[intentHash];

        if (status.isCancelled) {
            revert IntentIsCancelled();
        }

        if (!status.isPrevalidated) {
            _prevalidateIntent(
                intentHash,
                intent.maker,
                intent.isSmartOrder,
                intent.signature
            );
        }

        // Ensure there's still some amount left to be filled
        uint128 amountAvailable = intent.amount - status.amountFilled;
        if (amountAvailable == 0) {
            revert IntentIsFilled();
        }

        // Ensure non-partially-fillable intents are fully filled
        if (!intent.isPartiallyFillable && amountToFill < amountAvailable) {
            revert IntentIsNotPartiallyFillable();
        }

        // Compute the actual amount to fill
        actualAmountToFill = amountToFill > amountAvailable
            ? amountAvailable
            : amountToFill;
        if (actualAmountToFill == 0) {
            revert InvalidFillAmount();
        }

        // Update the storage
        intentStatus[intentHash].amountFilled += actualAmountToFill;

        if (intent.isBuy) {
            // When isBuy = true:
            // amount = buy amount
            // endAmount = sell end amount
            // startAmountBps = sell start amount bps
            // expectedAmountBps = sell expected amount bps

            uint128 endAmount = (intent.endAmount * actualAmountToFill) /
                intent.amount;
            uint128 startAmount = endAmount -
                (endAmount * intent.startAmountBps) /
                10000;

            //                                                      (now() - startTime)
            // maxAmount = startAmount + (endAmount - startAmount) ---------------------
            //                                                     (endTime - startTime)

            uint128 maxAmount = startAmount +
                ((endAmount - startAmount) *
                    (uint32(block.timestamp) - intent.startTime)) /
                (intent.endTime - intent.startTime);

            // Transfer inputs to solver
            _transferNativeOrERC20(
                intent.maker,
                msg.sender,
                intent.sellToken,
                maxAmount
            );
        } else {
            // When isBuy = false:
            // amount = sell amount
            // endAmount = buy end amount
            // startAmountBps = buy start amount bps
            // expectedAmountBps = buy expected amount bps

            // Transfer inputs to solver
            _transferNativeOrERC20(
                intent.maker,
                msg.sender,
                intent.sellToken,
                actualAmountToFill
            );
        }
    }

    function _postProcess(
        Intent memory intent,
        uint128 amountToFill,
        uint128 amountToCheck,
        uint128 makerBuyBalanceDiff,
        uint128 makerSellBalanceDiff,
        uint128 sourceBalanceDiff
    ) internal returns (uint256 requiredTip) {
        bytes32 intentHash = getIntentHash(intent);

        if (intent.isBuy) {
            // When isBuy = true:
            // amount = buy amount
            // endAmount = sell end amount
            // startAmountBps = sell start amount bps
            // expectedAmountBps = sell expected amount bps

            uint128 endAmount = (intent.endAmount * amountToFill) /
                intent.amount;
            uint128 startAmount = endAmount -
                (endAmount * intent.startAmountBps) /
                10000;
            uint128 expectedAmount = endAmount -
                (endAmount * intent.expectedAmountBps) /
                10000;

            //                                                      (now() - startTime)
            // maxAmount = startAmount + (endAmount - startAmount) ---------------------
            //                                                     (endTime - startTime)

            uint128 maxAmount = startAmount +
                ((endAmount - startAmount) *
                    (uint32(block.timestamp) - intent.startTime)) /
                (intent.endTime - intent.startTime);

            uint128 executeAmount = makerSellBalanceDiff;

            // The amount to execute should be lower than the maximum allowed amount
            if (executeAmount > maxAmount) {
                revert InvalidSolution();
            }

            // The amount to execute should be lower than the check amount
            if (executeAmount > amountToCheck) {
                revert AmountCheckFailed();
            }

            // Compute total fees
            uint128 sourceFees;
            if (intent.source != address(0)) {
                // Fee
                if (intent.feeBps > 0) {
                    sourceFees += (executeAmount * intent.feeBps) / 10000;
                }

                // Surplus fee
                if (intent.surplusBps > 0 && executeAmount < expectedAmount) {
                    sourceFees +=
                        ((expectedAmount - executeAmount) * intent.surplusBps) /
                        10000;
                }
            }

            // Ensure the correct amount of fees were paid
            if (sourceBalanceDiff < sourceFees) {
                revert InvalidSolution();
            }

            // Ensure the maker got the correct amount of tokens
            if (makerBuyBalanceDiff < amountToFill) {
                revert InvalidSolution();
            }

            if (intent.isIncentivized) {
                uint256 priorityFee = tx.gasprice - block.basefee;
                if (priorityFee != requiredPriorityFee) {
                    revert InvalidPriorityFee();
                }

                uint16 slippage = intent.expectedAmountBps;
                if (slippage == 0) {
                    slippage = defaultSlippage;
                }

                uint128 slippageUnit = (slippage * expectedAmount) / 10000;
                uint128 minValue = expectedAmount - slippageUnit * multiplier;
                uint128 maxValue = expectedAmount + slippageUnit;

                if (executeAmount >= maxValue) {
                    requiredTip = minTip;
                } else if (executeAmount <= minValue) {
                    requiredTip = maxTip;
                } else {
                    requiredTip =
                        maxTip -
                        ((executeAmount - minValue) * (maxTip - minTip)) /
                        (maxValue - minValue);
                }

                uint256 balance = address(this).balance;
                if (balance < requiredTip) {
                    revert InvalidTip();
                } else {
                    block.coinbase.transfer(requiredTip);
                }

                uint256 leftover = address(this).balance;
                if (leftover > 0) {
                    ISolutionERC20(msg.sender).refund{
                        value: address(this).balance
                    }();
                }
            }

            emit IntentSolved(
                intentHash,
                intent.isBuy,
                intent.buyToken,
                intent.sellToken,
                intent.maker,
                msg.sender,
                amountToFill,
                executeAmount
            );
        } else {
            // When isBuy = false:
            // amount = sell amount
            // endAmount = buy end amount
            // startAmountBps = buy start amount bps
            // expectedAmountBps = buy expected amount bps

            uint128 endAmount = (intent.endAmount * amountToFill) /
                intent.amount;
            uint128 startAmount = endAmount +
                (endAmount * intent.startAmountBps) /
                10000;
            uint128 expectedAmount = endAmount +
                (endAmount * intent.expectedAmountBps) /
                10000;

            //                                                      (now() - startTime)
            // minAmount = startAmount - (startAmount - endAmount) ---------------------
            //                                                     (endTime - startTime)

            uint128 minAmount = startAmount -
                ((startAmount - endAmount) *
                    (uint32(block.timestamp) - intent.startTime)) /
                (intent.endTime - intent.startTime);

            uint128 executeAmount = makerBuyBalanceDiff + sourceBalanceDiff;

            // The amount to execute should be greater than the minimum amount
            if (executeAmount < minAmount) {
                revert InvalidSolution();
            }

            // The amount to execute should be greater than the check amount
            if (executeAmount < amountToCheck) {
                revert AmountCheckFailed();
            }

            // Compute total fees
            uint128 sourceFees;
            if (intent.source != address(0)) {
                // Fee
                if (intent.feeBps > 0) {
                    sourceFees += (executeAmount * intent.feeBps) / 10000;
                }

                // Surplus fee
                if (intent.surplusBps > 0 && executeAmount > expectedAmount) {
                    sourceFees +=
                        ((executeAmount - expectedAmount) * intent.surplusBps) /
                        10000;
                }
            }

            // Ensure the correct amount of fees were paid
            if (sourceBalanceDiff < sourceFees) {
                revert InvalidSolution();
            }

            // Ensure the maker spent the correct amount of tokens
            if (makerSellBalanceDiff < amountToFill) {
                revert InvalidSolution();
            }

            if (intent.isIncentivized) {
                uint256 priorityFee = tx.gasprice - block.basefee;
                if (priorityFee != requiredPriorityFee) {
                    revert InvalidPriorityFee();
                }

                uint16 slippage = intent.expectedAmountBps;
                if (slippage == 0) {
                    slippage = defaultSlippage;
                }

                uint128 slippageUnit = (slippage * expectedAmount) / 10000;
                uint128 minValue = expectedAmount - slippageUnit;
                uint128 maxValue = expectedAmount + slippageUnit * multiplier;

                if (executeAmount >= maxValue) {
                    requiredTip = minTip;
                } else if (executeAmount <= minValue) {
                    requiredTip = maxTip;
                } else {
                    requiredTip =
                        minTip +
                        ((executeAmount - minValue) * (maxTip - minTip)) /
                        (maxValue - minValue);
                }

                uint256 balance = address(this).balance;
                if (balance < requiredTip) {
                    revert InvalidTip();
                } else {
                    block.coinbase.transfer(requiredTip);
                }

                uint256 leftover = address(this).balance;
                if (leftover > 0) {
                    ISolutionERC20(msg.sender).refund{
                        value: address(this).balance
                    }();
                }
            }

            emit IntentSolved(
                intentHash,
                intent.isBuy,
                intent.buyToken,
                intent.sellToken,
                intent.maker,
                msg.sender,
                executeAmount,
                amountToFill
            );
        }
    }

    /**
     * @dev Solve intent
     *
     * @param intent Intent to solve
     * @param solution Solution for the intent
     * @param amountToCheck The amount to check the solution against
     */
    function _solve(
        Intent memory intent,
        Solution calldata solution,
        uint128 amountToCheck
    ) internal {
        uint256 coinbaseBalanceBefore = block.coinbase.balance;

        // Determine the token for which the amount is variable
        // - isBuy = true -> sellToken (exact output, variable input)
        // - isBuy = false -> buyToken (exact input, variable output)
        address relevantToken = intent.isBuy
            ? intent.sellToken
            : intent.buyToken;

        // Fetch the balances before the solution execution
        uint128 makerBuyBalanceBefore = _getBalanceNativeOrERC20(
            intent.buyToken,
            intent.maker
        );
        uint128 makerSellBalanceBefore = _getBalanceNativeOrERC20(
            intent.sellToken,
            intent.maker
        );
        uint128 sourceBalanceBefore = _getBalanceNativeOrERC20(
            relevantToken,
            intent.source
        );

        // Pre-process
        uint128 actualAmountToFill = _preProcess(intent, solution.fillAmount);

        // Solve
        ISolutionERC20(msg.sender).callback(
            intent,
            actualAmountToFill,
            solution.data
        );

        // Fetch the balances after the solution execution
        uint128 makerBuyBalanceAfter = _getBalanceNativeOrERC20(
            intent.buyToken,
            intent.maker
        );
        uint128 makerSellBalanceAfter = _getBalanceNativeOrERC20(
            intent.sellToken,
            intent.maker
        );
        uint128 sourceBalanceAfter = _getBalanceNativeOrERC20(
            relevantToken,
            intent.source
        );

        // Post-process
        uint256 requiredTip = _postProcess(
            intent,
            actualAmountToFill,
            amountToCheck,
            makerBuyBalanceAfter - makerBuyBalanceBefore,
            makerSellBalanceBefore - makerSellBalanceAfter,
            sourceBalanceAfter - sourceBalanceBefore
        );

        MemswapAlphaNFT(MEMSWAP_ALPHA_NFT).mint(intent.maker);

        uint256 coinbaseBalanceAfter = block.coinbase.balance;
        if (
            intent.isIncentivized &&
            coinbaseBalanceAfter - coinbaseBalanceBefore != requiredTip
        ) {
            revert InvalidTip();
        }
    }

    /**
     * @dev Check an authorization
     *
     * @param auth Authorization to check
     * @param amount Amount to check the authorization against
     */
    function _checkAuthorization(
        Authorization memory auth,
        uint128 amount
    ) internal view {
        // Ensure the authorization is not expired
        if (auth.blockDeadline < block.number) {
            revert AuthorizationIsExpired();
        }

        // Ensure the amount to fill matches the authorized amount
        if (auth.fillAmountToCheck != amount) {
            revert AuthorizationAmountMismatch();
        }
    }

    /**
     * @dev Pre-validate an intent by checking its signature
     *
     * @param intentHash EIP712 intent struct hash to verify
     * @param maker The maker of the intent
     * @param isSmartOrder Whether the intent is a smart order
     * @param signature The signature of the intent
     */
    function _prevalidateIntent(
        bytes32 intentHash,
        address maker,
        bool isSmartOrder,
        bytes memory signature
    ) internal {
        _verifySignature(intentHash, maker, signature);

        // Mark the intent as validated if allowed
        if (!isSmartOrder) {
            intentStatus[intentHash].isPrevalidated = true;
        }
    }

    /**
     * @dev Make any private data available for an intent
     *
     * @param intent Intent to make private data available for
     */
    function _includePrivateData(Intent memory intent) internal view {
        if (intent.maker == address(0)) {
            bytes32 intentHash = getIntentHash(intent);
            bytes32 privateData = intentPrivateData[intentHash];

            // For byte conversions, right bits are stripped (we use `bytes20(...)`)
            address revealedMaker = address(uint160(bytes20(privateData)));
            // For numeric conversions, left bits are stripped (we use `uint96(uint256(...))`)
            bytes12 revealedSignaturePrefix = bytes12(
                uint96(uint256(privateData))
            );

            // Override the maker
            intent.maker = revealedMaker;

            // Override the signature prefix
            bytes memory signature = intent.signature;
            assembly {
                mstore(
                    add(signature, 0x20),
                    or(
                        and(
                            mload(add(signature, 0x20)),
                            not(shl(160, 0xffffffffffffffffffffffff))
                        ),
                        revealedSignaturePrefix
                    )
                )
            }
        }
    }

    /**
     * @dev Helper method to get the balance of native or ERC20 tokens
     *
     * @param token Token to get the balance for (native tokens are represented by the zero address)
     * @param owner Wallet to get the balance of
     *
     * @return balance The amount of `token` owned by `owner`
     */
    function _getBalanceNativeOrERC20(
        address token,
        address owner
    ) internal view returns (uint128 balance) {
        if (token == address(0)) {
            balance = uint128(owner.balance);
        } else {
            balance = uint128(IERC20(token).balanceOf(owner));
        }
    }

    /**
     * @dev Helper method for transferring native or ERC20 tokens
     *
     * @param from Transfer from this address
     * @param to Transfer to this address
     * @param token Token to transfer (native tokens are represented by the zero address)
     * @param amount Amount to transfer
     */
    function _transferNativeOrERC20(
        address from,
        address to,
        address token,
        uint256 amount
    ) internal {
        bool success;
        if (token == address(0)) {
            (success, ) = to.call{value: amount}("");
        } else {
            // First, attempt to transfer directly
            try IERC20(token).transferFrom(from, to, amount) {
                success = true;
            } catch {
                // Secondly, attempt to transfer via permit2
                _permit2TransferFrom(from, to, uint160(amount), token);
                success = true;
            }
        }

        if (!success) {
            revert UnsuccessfulCall();
        }
    }

    // --- Overridden methods ---

    function _lookupBulkOrderTypehash(
        uint256 treeHeight
    ) internal pure override returns (bytes32 typeHash) {
        // keccak256("BatchIntent(Intent[2]...[2] tree)Intent(bool isBuy,address buyToken,address sellToken,address maker,address solver,address source,uint16 feeBps,uint16 surplusBps,uint32 startTime,uint32 endTime,uint256 nonce,bool isPartiallyFillable,bool isSmartOrder,bool isIncentivized,uint128 amount,uint128 endAmount,uint16 startAmountBps,uint16 expectedAmountBps)")
        if (treeHeight == 1) {
            typeHash = 0x945d94161e2113b02bf0e182f366f2b49c50dae0d6b4cadf79490fff5e9d5d21;
        } else if (treeHeight == 2) {
            typeHash = 0x9e209c79444e36e3d4dbf12b64c493ae40e24454994a956cb26ab0be056fe054;
        } else if (treeHeight == 3) {
            typeHash = 0x64c8d79fdb76f3762a63fbcab9c8fe85e6f7642185a3fe06891df4e6a5b65995;
        } else if (treeHeight == 4) {
            typeHash = 0x6cf775cee971eeb656e22ab338d039139a243cfbff441dbc01338620e13fbf90;
        } else if (treeHeight == 5) {
            typeHash = 0x74b6db66988afe42dc67b9fc70688db72a3608c32f7c1c3bf199da73ba898b48;
        } else if (treeHeight == 6) {
            typeHash = 0xceec5d0dbe05897fb8bc2bf5c810b27c6e205e643b445e9a1f3ab44bace846de;
        } else if (treeHeight == 7) {
            typeHash = 0xe61dcdbdc2622edbe0073e024bc0c07de7def5c63ee7cab74e3ab7525e053213;
        } else if (treeHeight == 8) {
            typeHash = 0x6878d00790537f609a965823f50c7704250ab4ff24d4617ea8f721f6f374f106;
        } else {
            revert MerkleTreeTooLarge();
        }
    }
}

// File: contracts/erc721/interfaces/ISolutionERC721.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

import {MemswapERC721} from "../MemswapERC721.sol";

interface ISolutionERC721 {
    function callback(
        MemswapERC721.Intent memory intent,
        MemswapERC721.TokenDetails[] memory tokenDetailsToFill,
        bytes memory data
    ) external;

    function refund() external payable;
}

// File: contracts/erc721/MemswapERC721.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721.sol";

import {EIP712} from "../common/EIP712.sol";
import {PermitExecutor} from "../common/PermitExecutor.sol";
import {SignatureVerification} from "../common/SignatureVerification.sol";
import {MemswapAlphaNFT} from "../nft/MemswapAlphaNFT.sol";

import {ISolutionERC721} from "./interfaces/ISolutionERC721.sol";

contract MemswapERC721 is
    Ownable,
    PermitExecutor,
    ReentrancyGuard,
    SignatureVerification
{
    // --- Structs and enums ---

    struct Intent {
        // When isBuy = true:
        // amount = buy amount
        // endAmount = sell end amount
        // startAmountBps = sell start amount bps
        // expectedAmountBps = sell expected amount bps

        // When isBuy = false:
        // amount = sell amount
        // endAmount = buy end amount
        // startAmountBps = buy start amount bps
        // expectedAmountBps = buy expected amount bps

        // Exact output (isBuy = true) or exact input (isBuy = false)
        bool isBuy;
        address buyToken;
        address sellToken;
        address maker;
        // The address allowed to solve or authorize others to solve
        address solver;
        address source;
        uint16 feeBps;
        uint16 surplusBps;
        uint32 startTime;
        uint32 endTime;
        bool isPartiallyFillable;
        bool isSmartOrder;
        bool isIncentivized;
        bool isCriteriaOrder;
        uint256 tokenIdOrCriteria;
        uint128 amount;
        uint128 endAmount;
        uint16 startAmountBps;
        uint16 expectedAmountBps;
        bytes signature;
    }

    struct IntentStatus {
        bool isPrevalidated;
        bool isCancelled;
        uint128 amountFilled;
    }

    struct Authorization {
        // When isBuy = true:
        // fillAmountToCheck = buy amount to fill
        // executeAmountToCheck = maximum sell amount pulled from user

        // When isBuy = false:
        // fillAmountToCheck = sell amount to fill
        // executeAmountToCheck = minimum buy amount pushed to user

        uint128 fillAmountToCheck;
        uint128 executeAmountToCheck;
        uint32 blockDeadline;
    }

    struct TokenDetails {
        uint256 tokenId;
        bytes32[] criteriaProof;
    }

    struct Solution {
        // When isBuy = true:
        // fillTokenDetails = tokens to push to user

        // When isBuy = false:
        // fillTokenDetails = tokens to pull from user

        bytes data;
        TokenDetails[] fillTokenDetails;
    }

    // --- Events ---

    event IncentivizationParametersUpdated();
    event IntentCancelled(bytes32 indexed intentHash);
    event IntentPrevalidated(bytes32 indexed intentHash);
    event IntentSolved(
        bytes32 indexed intentHash,
        bool isBuy,
        address buyToken,
        address sellToken,
        address maker,
        address solver,
        uint128 amount,
        uint256[] tokenIds
    );
    event IntentsPosted();
    event NonceIncremented(address maker, uint256 newNonce);

    // --- Errors ---

    error AmountCheckFailed();
    error AuthorizationAmountMismatch();
    error AuthorizationIsExpired();
    error IntentCannotBePrevalidated();
    error IntentIsCancelled();
    error IntentIsExpired();
    error IntentIsFilled();
    error IntentIsNotPartiallyFillable();
    error IntentIsNotStarted();
    error InvalidCriteriaProof();
    error InvalidFillAmount();
    error InvalidPriorityFee();
    error InvalidSolution();
    error InvalidStartAndEndTimes();
    error InvalidTip();
    error InvalidTokenId();
    error MerkleTreeTooLarge();
    error Unauthorized();
    error UnsuccessfulCall();

    // --- Fields ---

    bytes32 public immutable AUTHORIZATION_TYPEHASH;
    bytes32 public immutable INTENT_TYPEHASH;
    address public immutable MEMSWAP_ALPHA_NFT;

    mapping(address => uint256) public nonce;
    mapping(bytes32 => bytes32) public intentPrivateData;
    mapping(bytes32 => IntentStatus) public intentStatus;
    mapping(bytes32 => Authorization) public authorization;

    // Relevant for incentivized intents
    uint16 public defaultSlippage;
    uint16 public multiplier;
    uint64 public requiredPriorityFee;
    uint64 public minTip;
    uint64 public maxTip;

    // --- Constructor ---

    constructor(address memswapAlphaNft) EIP712("MemswapERC721", "1.0") {
        AUTHORIZATION_TYPEHASH = keccak256(
            abi.encodePacked(
                "Authorization(",
                "bytes32 intentHash,",
                "address solver,",
                "uint128 fillAmountToCheck,",
                "uint128 executeAmountToCheck,",
                "uint32 blockDeadline",
                ")"
            )
        );

        INTENT_TYPEHASH = keccak256(
            abi.encodePacked(
                "Intent(",
                "bool isBuy,",
                "address buyToken,",
                "address sellToken,",
                "address maker,",
                "address solver,",
                "address source,",
                "uint16 feeBps,",
                "uint16 surplusBps,",
                "uint32 startTime,",
                "uint32 endTime,",
                "uint256 nonce,",
                "bool isPartiallyFillable,",
                "bool isSmartOrder,",
                "bool isIncentivized,",
                "bool isCriteriaOrder,",
                "uint256 tokenIdOrCriteria,",
                "uint128 amount,",
                "uint128 endAmount,",
                "uint16 startAmountBps,",
                "uint16 expectedAmountBps",
                ")"
            )
        );

        MEMSWAP_ALPHA_NFT = memswapAlphaNft;

        defaultSlippage = 50;
        multiplier = 4;
        requiredPriorityFee = 1 gwei;
        minTip = 0.05 gwei * 500000;
        maxTip = 1.5 gwei * 500000;
    }

    // Fallback

    receive() external payable {}

    // Owner methods

    function updateIncentivizationParameters(
        uint16 newDefaultSlippage,
        uint16 newMultiplier,
        uint64 newRequiredPriorityFee,
        uint64 newMinTip,
        uint64 newMaxTip
    ) external onlyOwner {
        defaultSlippage = newDefaultSlippage;
        multiplier = newMultiplier;
        requiredPriorityFee = newRequiredPriorityFee;
        minTip = newMinTip;
        maxTip = newMaxTip;

        emit IncentivizationParametersUpdated();
    }

    // Public methods

    /**
     * @notice Authorize an address to solve particular intents
     *
     * @param intents Intents to solve
     * @param auths Authorizations
     * @param solver The address authorized to solve
     */
    function authorize(
        Intent[] calldata intents,
        Authorization[] calldata auths,
        address solver
    ) external {
        unchecked {
            uint256 intentsLength = intents.length;
            for (uint256 i; i < intentsLength; i++) {
                Intent calldata intent = intents[i];
                Authorization calldata auth = auths[i];

                if (intent.solver != msg.sender) {
                    revert Unauthorized();
                }

                bytes32 intentHash = getIntentHash(intent);
                bytes32 authId = keccak256(
                    abi.encodePacked(intentHash, solver)
                );
                authorization[authId] = auth;
            }
        }
    }

    /**
     * @notice Make intents available on-chain (this method doesn't do anything
     *         useful - it's only used as a mechanism for intent distribution)
     *
     * @custom:param intents Intents being made available
     */
    function post(
        /**
         * @custom:name intents
         */
        Intent[] calldata
    ) external {
        emit IntentsPosted();
    }

    /**
     * @notice Pre-validate an arbitrary number of intents (the signature of each
     *         intent will be checked, thus resulting in skipping verification on
     *         further attempts to solve the intent, unless the intent explicitly
     *         enforces checking the signature on every fill)
     *
     * @param intents Intents to validate
     */
    function prevalidate(Intent[] calldata intents) external {
        unchecked {
            uint256 intentsLength = intents.length;
            for (uint256 i; i < intentsLength; i++) {
                Intent calldata intent = intents[i];
                if (intent.isSmartOrder) {
                    revert IntentCannotBePrevalidated();
                }

                bytes32 intentHash = getIntentHash(intent);

                _prevalidateIntent(
                    intentHash,
                    intent.maker,
                    intent.isSmartOrder,
                    intent.signature
                );
                emit IntentPrevalidated(intentHash);
            }
        }
    }

    /**
     * @notice Cancel an arbitrary number of intents
     *
     * @param intents Intents to cancel
     */
    function cancel(Intent[] calldata intents) external {
        unchecked {
            uint256 intentsLength = intents.length;
            for (uint256 i; i < intentsLength; i++) {
                Intent calldata intent = intents[i];
                if (intent.maker != msg.sender) {
                    revert Unauthorized();
                }

                bytes32 intentHash = getIntentHash(intent);
                IntentStatus memory status = intentStatus[intentHash];
                status.isPrevalidated = false;
                status.isCancelled = true;

                intentStatus[intentHash] = status;
                emit IntentCancelled(intentHash);
            }
        }
    }

    /**
     * @notice Increment the nonce for `msg.sender`. This will result in
     *         the invalidation of any intents signed with a lower nonce
     *         than the latest value.
     */
    function incrementNonce() external {
        unchecked {
            uint256 newNonce = nonce[msg.sender] + 1;
            nonce[msg.sender] = newNonce;
            emit NonceIncremented(msg.sender, newNonce);
        }
    }

    /**
     * @notice Reveal intents by making available data assumed to not be publicly
     *         available (maker + signature prefix). This method should be called
     *         right before the solution transaction, ideally bundled, so that no
     *         details are revealed sooner than it should be.
     *
     * @param intents Intents to reveal
     */
    function reveal(Intent[] memory intents) external {
        unchecked {
            uint256 intentsLength = intents.length;
            for (uint256 i; i < intentsLength; i++) {
                Intent memory intent = intents[i];

                // Ensure the intent is valid
                bytes32 intentHash = getIntentHash(intent);
                _verifySignature(intentHash, intent.maker, intent.signature);

                // Extract the private data (intent + signature prefix)
                address maker = intent.maker;
                bytes12 signaturePrefix = bytes12(intent.signature);

                // Override the maker with the zero address to get the correct partial intent hash
                intent.maker = address(0);

                // Store the private data (intent + signature prefix)
                bytes32 partialIntentHash = getIntentHash(intent);
                intentPrivateData[partialIntentHash] = bytes32(
                    abi.encodePacked(maker, signaturePrefix)
                );
            }
        }
    }

    /**
     * @notice Solve intent
     *
     * @param intent Intent to solve
     * @param solution Solution
     * @param permits Permits to execute prior to the solution
     */
    function solve(
        Intent memory intent,
        Solution calldata solution,
        PermitExecutor.Permit[] calldata permits
    ) external payable nonReentrant executePermits(permits) {
        // Make any private data available
        _includePrivateData(intent);

        // Check authorization
        if (intent.solver != address(0) && intent.solver != msg.sender) {
            revert Unauthorized();
        }

        // Solve
        _solve(intent, solution, intent.isBuy ? type(uint128).max : 0);
    }

    /**
     * @notice Solve intent with authorization. Compared to the regular `solve`,
     *         this method allows solving intents of a different solver, as long
     *         as there's a valid authorization in-place for the current caller.
     *         The authorization will be checked via a storage slot.
     *
     * @param intent Intent to solve
     * @param solution Solution
     * @param permits Permits to execute prior to the solution
     */
    function solveWithOnChainAuthorizationCheck(
        Intent memory intent,
        Solution calldata solution,
        PermitExecutor.Permit[] calldata permits
    ) external payable nonReentrant executePermits(permits) {
        // Make any private data available
        _includePrivateData(intent);

        // Check authorization
        bytes32 intentHash = getIntentHash(intent);
        bytes32 authId = keccak256(abi.encodePacked(intentHash, msg.sender));
        Authorization memory auth = authorization[authId];
        _checkAuthorization(auth, uint128(solution.fillTokenDetails.length));

        // Solve
        _solve(intent, solution, auth.executeAmountToCheck);
    }

    /**
     * @notice Solve intent with authorization. Compared to the regular `solve`,
     *         this method allows solving intents of a different solver, as long
     *         as there's a valid authorization in-place for the current caller.
     *         The authorization will be checked via a signature.
     *
     * @param intent Intent to solve
     * @param solution Solution for the intent
     * @param auth Authorization
     * @param authSignature Authorization signature
     * @param permits Permits to execute prior to the solution
     */
    function solveWithSignatureAuthorizationCheck(
        Intent memory intent,
        Solution calldata solution,
        Authorization calldata auth,
        bytes calldata authSignature,
        PermitExecutor.Permit[] calldata permits
    ) external payable nonReentrant executePermits(permits) {
        // Make any private data available
        _includePrivateData(intent);

        // Check authorization
        bytes32 intentHash = getIntentHash(intent);
        bytes32 authorizationHash = getAuthorizationHash(
            intentHash,
            msg.sender,
            auth
        );
        bytes32 digest = _getEIP712Hash(authorizationHash);
        _assertValidSignature(
            intent.solver,
            digest,
            digest,
            authSignature.length,
            authSignature
        );
        _checkAuthorization(auth, uint128(solution.fillTokenDetails.length));

        // Solve
        _solve(intent, solution, auth.executeAmountToCheck);
    }

    // View methods

    /**
     * @notice Get the EIP712 struct hash for an authorization
     *
     * @param intentHash Intent EIP712 struct hash to authorize
     * @param solver Solver to authorize
     * @param auth Authorization details/conditions
     *
     * @return authorizationHash The EIP712 struct hash of the authorization
     */
    function getAuthorizationHash(
        bytes32 intentHash,
        address solver,
        Authorization memory auth
    ) public view returns (bytes32 authorizationHash) {
        authorizationHash = keccak256(
            abi.encode(
                AUTHORIZATION_TYPEHASH,
                intentHash,
                solver,
                auth.fillAmountToCheck,
                auth.executeAmountToCheck,
                auth.blockDeadline
            )
        );
    }

    /**
     * @notice Get the EIP712 struct hash for an intent
     *
     * @param intent Intent to compute the hash for
     *
     * @return intentHash The EIP712 struct hash of the intent
     */
    function getIntentHash(
        Intent memory intent
    ) public view returns (bytes32 intentHash) {
        intentHash = keccak256(
            bytes.concat(
                abi.encode(
                    INTENT_TYPEHASH,
                    intent.isBuy,
                    intent.buyToken,
                    intent.sellToken,
                    intent.maker,
                    intent.solver,
                    intent.source,
                    intent.feeBps,
                    intent.surplusBps,
                    intent.startTime,
                    intent.endTime,
                    nonce[intent.maker]
                ),
                abi.encode(
                    intent.isPartiallyFillable,
                    intent.isSmartOrder,
                    intent.isIncentivized,
                    intent.isCriteriaOrder,
                    intent.tokenIdOrCriteria,
                    intent.amount,
                    intent.endAmount,
                    intent.startAmountBps,
                    intent.expectedAmountBps
                )
            )
        );
    }

    // Internal methods

    function _preProcess(
        Intent memory intent,
        TokenDetails[] memory tokenDetailsToFill
    ) internal returns (TokenDetails[] memory actualTokenDetailsToFill) {
        bytes32 intentHash = getIntentHash(intent);

        // Verify start and end times

        if (intent.startTime > block.timestamp) {
            revert IntentIsNotStarted();
        }

        if (intent.endTime < block.timestamp) {
            revert IntentIsExpired();
        }

        if (intent.startTime >= intent.endTime) {
            revert InvalidStartAndEndTimes();
        }

        // Verify cancellation status and signature

        IntentStatus memory status = intentStatus[intentHash];

        if (status.isCancelled) {
            revert IntentIsCancelled();
        }

        if (!status.isPrevalidated) {
            _prevalidateIntent(
                intentHash,
                intent.maker,
                intent.isSmartOrder,
                intent.signature
            );
        }

        // Ensure there's still some amount left to be filled
        uint128 amountAvailable = intent.amount - status.amountFilled;
        if (amountAvailable == 0) {
            revert IntentIsFilled();
        }

        uint128 amountToFill = uint128(tokenDetailsToFill.length);

        // Ensure non-partially-fillable intents are fully filled
        if (!intent.isPartiallyFillable && amountToFill < amountAvailable) {
            revert IntentIsNotPartiallyFillable();
        }

        // Compute the actual amount to fill
        uint128 actualAmountToFill = amountToFill > amountAvailable
            ? amountAvailable
            : amountToFill;
        if (actualAmountToFill == 0) {
            revert InvalidFillAmount();
        }

        // Update the storage
        intentStatus[intentHash].amountFilled += actualAmountToFill;

        actualTokenDetailsToFill = new TokenDetails[](actualAmountToFill);
        unchecked {
            for (uint256 i; i < actualAmountToFill; i++) {
                actualTokenDetailsToFill[i] = tokenDetailsToFill[i];
            }
        }

        if (intent.isBuy) {
            // When isBuy = true:
            // amount = buy amount
            // endAmount = sell end amount
            // startAmountBps = sell start amount bps
            // expectedAmountBps = sell expected amount bps

            uint128 endAmount = (intent.endAmount * actualAmountToFill) /
                intent.amount;
            uint128 startAmount = endAmount -
                (endAmount * intent.startAmountBps) /
                10000;

            //                                                      (now() - startTime)
            // maxAmount = startAmount + (endAmount - startAmount) ---------------------
            //                                                     (endTime - startTime)

            uint128 maxAmount = startAmount +
                ((endAmount - startAmount) *
                    (uint32(block.timestamp) - intent.startTime)) /
                (intent.endTime - intent.startTime);

            // Transfer inputs to solver
            _transferNativeOrERC20(
                intent.maker,
                msg.sender,
                intent.sellToken,
                maxAmount
            );

            // Ensure the maker doesn't own any of the tokens that are being filled with
            unchecked {
                for (uint256 i; i < actualAmountToFill; i++) {
                    TokenDetails memory details = tokenDetailsToFill[i];
                    try
                        IERC721(intent.buyToken).ownerOf(details.tokenId)
                    returns (address owner) {
                        if (owner == intent.maker) {
                            revert InvalidSolution();
                        }
                    } catch {
                        // Skip errors (to support not-yet-minted tokens)
                    }
                }
            }
        } else {
            // When isBuy = false:
            // amount = sell amount
            // endAmount = buy end amount
            // startAmountBps = buy start amount bps
            // expectedAmountBps = buy expected amount bps

            unchecked {
                for (uint256 i; i < actualAmountToFill; i++) {
                    TokenDetails memory details = tokenDetailsToFill[i];

                    if (intent.isCriteriaOrder) {
                        if (intent.tokenIdOrCriteria != 0) {
                            _verifyCriteriaProof(
                                details.tokenId,
                                intent.tokenIdOrCriteria,
                                details.criteriaProof
                            );
                        }
                    } else {
                        if (intent.tokenIdOrCriteria != details.tokenId) {
                            revert InvalidTokenId();
                        }
                    }

                    // Transfer inputs to solver
                    _transferERC721(
                        intent.maker,
                        msg.sender,
                        intent.sellToken,
                        details.tokenId
                    );
                }
            }
        }
    }

    function _postProcess(
        Intent memory intent,
        TokenDetails[] memory tokenDetailsToFill,
        uint128 amountToCheck,
        uint128 makerBuyBalanceDiff,
        uint128 makerSellBalanceDiff,
        uint128 sourceBalanceDiff
    ) internal returns (uint256 requiredTip) {
        bytes32 intentHash = getIntentHash(intent);

        uint128 amountToFill = uint128(tokenDetailsToFill.length);
        if (intent.isBuy) {
            // When isBuy = true:
            // amount = buy amount
            // endAmount = sell end amount
            // startAmountBps = sell start amount bps
            // expectedAmountBps = sell expected amount bps

            uint128 endAmount = (intent.endAmount * amountToFill) /
                intent.amount;
            uint128 startAmount = endAmount -
                (endAmount * intent.startAmountBps) /
                10000;
            uint128 expectedAmount = endAmount -
                (endAmount * intent.expectedAmountBps) /
                10000;

            //                                                      (now() - startTime)
            // maxAmount = startAmount + (endAmount - startAmount) ---------------------
            //                                                     (endTime - startTime)

            uint128 maxAmount = startAmount +
                ((endAmount - startAmount) *
                    (uint32(block.timestamp) - intent.startTime)) /
                (intent.endTime - intent.startTime);

            uint128 executeAmount = makerSellBalanceDiff;

            // The amount to execute should be lower than the maximum allowed amount
            if (executeAmount > maxAmount) {
                revert InvalidSolution();
            }

            // The amount to execute should be lower than the check amount
            if (executeAmount > amountToCheck) {
                revert AmountCheckFailed();
            }

            // Compute total fees
            uint128 sourceFees;
            if (intent.source != address(0)) {
                // Fee
                if (intent.feeBps > 0) {
                    sourceFees += (executeAmount * intent.feeBps) / 10000;
                }

                // Surplus fee
                if (intent.surplusBps > 0 && executeAmount < expectedAmount) {
                    sourceFees +=
                        ((expectedAmount - executeAmount) * intent.surplusBps) /
                        10000;
                }
            }

            // Ensure the correct amount of fees were paid
            if (sourceBalanceDiff < sourceFees) {
                revert InvalidSolution();
            }

            // Ensure the maker got the correct amount of tokens
            if (makerBuyBalanceDiff < amountToFill) {
                revert InvalidSolution();
            }

            // Ensure the maker owns all tokens that are being filled with
            uint256[] memory filledTokenIds = new uint256[](amountToFill);
            unchecked {
                for (uint256 i; i < amountToFill; i++) {
                    TokenDetails memory details = tokenDetailsToFill[i];

                    if (intent.isCriteriaOrder) {
                        if (intent.tokenIdOrCriteria != 0) {
                            _verifyCriteriaProof(
                                details.tokenId,
                                intent.tokenIdOrCriteria,
                                details.criteriaProof
                            );
                        }
                    } else {
                        if (intent.tokenIdOrCriteria != details.tokenId) {
                            revert InvalidTokenId();
                        }
                    }

                    if (
                        IERC721(intent.buyToken).ownerOf(details.tokenId) !=
                        intent.maker
                    ) {
                        revert InvalidSolution();
                    }

                    filledTokenIds[i] = details.tokenId;
                }
            }

            if (intent.isIncentivized) {
                uint256 priorityFee = tx.gasprice - block.basefee;
                if (priorityFee != requiredPriorityFee) {
                    revert InvalidPriorityFee();
                }

                uint16 slippage = intent.expectedAmountBps;
                if (slippage == 0) {
                    slippage = defaultSlippage;
                }

                uint128 slippageUnit = (slippage * expectedAmount) / 10000;
                uint128 minValue = expectedAmount - slippageUnit * multiplier;
                uint128 maxValue = expectedAmount + slippageUnit;

                if (executeAmount >= maxValue) {
                    requiredTip = minTip;
                } else if (executeAmount <= minValue) {
                    requiredTip = maxTip;
                } else {
                    requiredTip =
                        maxTip -
                        ((executeAmount - minValue) * (maxTip - minTip)) /
                        (maxValue - minValue);
                }

                uint256 balance = address(this).balance;
                if (balance < requiredTip) {
                    revert InvalidTip();
                } else {
                    block.coinbase.transfer(requiredTip);
                }

                uint256 leftover = address(this).balance;
                if (leftover > 0) {
                    ISolutionERC721(msg.sender).refund{
                        value: address(this).balance
                    }();
                }
            }

            emit IntentSolved(
                intentHash,
                intent.isBuy,
                intent.buyToken,
                intent.sellToken,
                intent.maker,
                msg.sender,
                executeAmount,
                filledTokenIds
            );
        } else {
            // When isBuy = false:
            // amount = sell amount
            // endAmount = buy end amount
            // startAmountBps = buy start amount bps
            // expectedAmountBps = buy expected amount bps

            uint128 endAmount = (intent.endAmount * amountToFill) /
                intent.amount;
            uint128 startAmount = endAmount +
                (endAmount * intent.startAmountBps) /
                10000;
            uint128 expectedAmount = endAmount +
                (endAmount * intent.expectedAmountBps) /
                10000;

            //                                                      (now() - startTime)
            // minAmount = startAmount - (startAmount - endAmount) ---------------------
            //                                                     (endTime - startTime)

            uint128 minAmount = startAmount -
                ((startAmount - endAmount) *
                    (uint32(block.timestamp) - intent.startTime)) /
                (intent.endTime - intent.startTime);

            uint128 executeAmount = makerBuyBalanceDiff + sourceBalanceDiff;

            // The amount to execute should be greater than the minimum amount
            if (executeAmount < minAmount) {
                revert InvalidSolution();
            }

            // The amount to execute should be greater than the check amount
            if (executeAmount < amountToCheck) {
                revert AmountCheckFailed();
            }

            // Compute total fees
            uint128 sourceFees;
            if (intent.source != address(0)) {
                // Fee
                if (intent.feeBps > 0) {
                    sourceFees += (executeAmount * intent.feeBps) / 10000;
                }

                // Surplus fee
                if (intent.surplusBps > 0 && executeAmount > expectedAmount) {
                    sourceFees +=
                        ((executeAmount - expectedAmount) * intent.surplusBps) /
                        10000;
                }
            }

            // Ensure the correct amount of fees were paid
            if (sourceBalanceDiff < sourceFees) {
                revert InvalidSolution();
            }

            // Ensure the maker spent the correct amount of tokens
            if (makerSellBalanceDiff < amountToFill) {
                revert InvalidSolution();
            }

            uint256[] memory filledTokenIds = new uint256[](amountToFill);
            unchecked {
                for (uint256 i; i < amountToFill; i++) {
                    TokenDetails memory details = tokenDetailsToFill[i];
                    filledTokenIds[i] = details.tokenId;
                }
            }

            if (intent.isIncentivized) {
                uint256 priorityFee = tx.gasprice - block.basefee;
                if (priorityFee != requiredPriorityFee) {
                    revert InvalidPriorityFee();
                }

                uint16 slippage = intent.expectedAmountBps;
                if (slippage == 0) {
                    slippage = defaultSlippage;
                }

                uint128 slippageUnit = (slippage * expectedAmount) / 10000;
                uint128 minValue = expectedAmount - slippageUnit;
                uint128 maxValue = expectedAmount + slippageUnit * multiplier;

                if (executeAmount >= maxValue) {
                    requiredTip = minTip;
                } else if (executeAmount <= minValue) {
                    requiredTip = maxTip;
                } else {
                    requiredTip =
                        minTip +
                        ((executeAmount - minValue) * (maxTip - minTip)) /
                        (maxValue - minValue);
                }

                uint256 balance = address(this).balance;
                if (balance < requiredTip) {
                    revert InvalidTip();
                } else {
                    block.coinbase.transfer(requiredTip);
                }

                uint256 leftover = address(this).balance;
                if (leftover > 0) {
                    ISolutionERC721(msg.sender).refund{
                        value: address(this).balance
                    }();
                }
            }

            emit IntentSolved(
                intentHash,
                intent.isBuy,
                intent.buyToken,
                intent.sellToken,
                intent.maker,
                msg.sender,
                executeAmount,
                filledTokenIds
            );
        }
    }

    /**
     * @dev Solve intent
     *
     * @param intent Intent to solve
     * @param solution Solution for the intent
     * @param amountToCheck The amount to check the solution against
     */
    function _solve(
        Intent memory intent,
        Solution calldata solution,
        uint128 amountToCheck
    ) internal {
        uint256 coinbaseBalanceBefore = block.coinbase.balance;

        // Determine the token for which the amount is variable
        // - isBuy = true -> sellToken (exact output, variable input)
        // - isBuy = false -> buyToken (exact input, variable output)
        address relevantToken = intent.isBuy
            ? intent.sellToken
            : intent.buyToken;

        // Fetch the balances before the solution execution
        uint128 makerBuyBalanceBefore = _getBalanceNativeOrERC20OrERC721(
            intent.buyToken,
            intent.maker
        );
        uint128 makerSellBalanceBefore = _getBalanceNativeOrERC20OrERC721(
            intent.sellToken,
            intent.maker
        );
        uint128 sourceBalanceBefore = _getBalanceNativeOrERC20OrERC721(
            relevantToken,
            intent.source
        );

        // Pre-process
        TokenDetails[] memory actualTokenDetailsToFill = _preProcess(
            intent,
            solution.fillTokenDetails
        );

        // Solve
        ISolutionERC721(msg.sender).callback(
            intent,
            actualTokenDetailsToFill,
            solution.data
        );

        // Fetch the balances after the solution execution
        uint128 makerBuyBalanceAfter = _getBalanceNativeOrERC20OrERC721(
            intent.buyToken,
            intent.maker
        );
        uint128 makerSellBalanceAfter = _getBalanceNativeOrERC20OrERC721(
            intent.sellToken,
            intent.maker
        );
        uint128 sourceBalanceAfter = _getBalanceNativeOrERC20OrERC721(
            relevantToken,
            intent.source
        );

        // Post-process
        uint256 requiredTip = _postProcess(
            intent,
            actualTokenDetailsToFill,
            amountToCheck,
            makerBuyBalanceAfter - makerBuyBalanceBefore,
            makerSellBalanceBefore - makerSellBalanceAfter,
            sourceBalanceAfter - sourceBalanceBefore
        );

        MemswapAlphaNFT(MEMSWAP_ALPHA_NFT).mint(intent.maker);

        uint256 coinbaseBalanceAfter = block.coinbase.balance;
        if (
            intent.isIncentivized &&
            coinbaseBalanceAfter - coinbaseBalanceBefore != requiredTip
        ) {
            revert InvalidTip();
        }
    }

    /**
     * @dev Check an authorization
     *
     * @param auth Authorization to check
     * @param amount Amount to check the authorization against
     */
    function _checkAuthorization(
        Authorization memory auth,
        uint128 amount
    ) internal view {
        // Ensure the authorization is not expired
        if (auth.blockDeadline < block.number) {
            revert AuthorizationIsExpired();
        }

        // Ensure the amount to fill matches the authorized amount
        if (auth.fillAmountToCheck != amount) {
            revert AuthorizationAmountMismatch();
        }
    }

    /**
     * @dev Pre-validate an intent by checking its signature
     *
     * @param intentHash EIP712 intent struct hash to verify
     * @param maker The maker of the intent
     * @param hasDynamicSignature Whether the intent has a dynamic signature
     * @param signature The signature of the intent
     */
    function _prevalidateIntent(
        bytes32 intentHash,
        address maker,
        bool hasDynamicSignature,
        bytes memory signature
    ) internal {
        _verifySignature(intentHash, maker, signature);

        // Mark the intent as validated if allowed
        if (!hasDynamicSignature) {
            intentStatus[intentHash].isPrevalidated = true;
        }
    }

    /**
     * @dev Make any private data available for an intent
     *
     * @param intent Intent to make private data available for
     */
    function _includePrivateData(Intent memory intent) internal view {
        if (intent.maker == address(0)) {
            bytes32 intentHash = getIntentHash(intent);
            bytes32 privateData = intentPrivateData[intentHash];

            // For byte conversions, right bits are stripped (we use `bytes20(...)`)
            address revealedMaker = address(uint160(bytes20(privateData)));
            // For numeric conversions, left bits are stripped (we use `uint96(uint256(...))`)
            bytes12 revealedSignaturePrefix = bytes12(
                uint96(uint256(privateData))
            );

            // Override the maker
            intent.maker = revealedMaker;

            // Override the signature prefix
            bytes memory signature = intent.signature;
            assembly {
                mstore(
                    add(signature, 0x20),
                    or(
                        and(
                            mload(add(signature, 0x20)),
                            not(shl(160, 0xFFFFFFFFFFFFFFFFFFFFFFFF))
                        ),
                        revealedSignaturePrefix
                    )
                )
            }
        }
    }

    /**
     * @dev Helper method to get the balance of native or ERC20/ERC721 tokens
     *
     * @param token Token to get the balance for (native tokens are represented by the zero address)
     * @param owner Wallet to get the balance of
     *
     * @return balance The amount of `token` owned by `owner`
     */
    function _getBalanceNativeOrERC20OrERC721(
        address token,
        address owner
    ) internal view returns (uint128 balance) {
        if (token == address(0)) {
            balance = uint128(owner.balance);
        } else {
            // Same interface for ERC20 and ERC721
            balance = uint128(IERC20(token).balanceOf(owner));
        }
    }

    /**
     * @dev Helper method for transferring native and ERC20 tokens
     *
     * @param from Transfer from this address
     * @param to Transfer to this address
     * @param token Token to transfer (native tokens are represented by the zero address)
     * @param amount Amonut to transfer
     */
    function _transferNativeOrERC20(
        address from,
        address to,
        address token,
        uint256 amount
    ) internal {
        bool success;
        if (address(token) == address(0)) {
            (success, ) = to.call{value: amount}("");
        } else {
            // First, attempt to transfer directly
            try IERC20(token).transferFrom(from, to, amount) {
                success = true;
            } catch {
                // Secondly, attempt to transfer via permit2
                _permit2TransferFrom(from, to, uint160(amount), token);
                success = true;
            }
        }

        if (!success) {
            revert UnsuccessfulCall();
        }
    }

    /**
     * @dev Helper method for transferring ERC721 tokens
     *
     * @param from Transfer from this address
     * @param to Transfer to this address
     * @param token Token to transfer
     * @param tokenId Token id to transfer
     */
    function _transferERC721(
        address from,
        address to,
        address token,
        uint256 tokenId
    ) internal {
        IERC721(token).transferFrom(from, to, tokenId);
    }

    /**
     * @dev Verify a merkle proof
     *      Taken from: https://github.com/ProjectOpenSea/seaport/blob/dfce06d02413636f324f73352b54a4497d63c310/contracts/lib/CriteriaResolution.sol#L243-L247
     *
     * @param leaf Leaf to verify
     * @param root Merkle root
     * @param criteriaProof Merkle proof for the inclusion of `leaf` in `root`
     */
    function _verifyCriteriaProof(
        uint256 leaf,
        uint256 root,
        bytes32[] memory criteriaProof
    ) internal pure {
        bool isValid;

        assembly {
            // Store the leaf at the beginning of scratch space
            mstore(0, leaf)

            // Derive the hash of the leaf to use as the initial proof element
            let computedHash := keccak256(0, 0x20)
            // Get memory start location of the first element in proof array
            let data := add(criteriaProof, 0x20)

            for {
                // Left shift by 5 is equivalent to multiplying by 0x20
                let end := add(data, shl(5, mload(criteriaProof)))
            } lt(data, end) {
                // Increment by one word at a time
                data := add(data, 0x20)
            } {
                // Get the proof element
                let loadedData := mload(data)

                // Sort proof elements and place them in scratch space
                let scratch := shl(5, gt(computedHash, loadedData))
                mstore(scratch, computedHash)
                mstore(xor(scratch, 0x20), loadedData)

                // Derive the updated hash
                computedHash := keccak256(0, 0x40)
            }

            isValid := eq(computedHash, root)
        }

        if (!isValid) {
            revert InvalidCriteriaProof();
        }
    }

    // --- Overridden methods ---

    function _lookupBulkOrderTypehash(
        uint256 treeHeight
    ) internal pure override returns (bytes32 typeHash) {
        // keccak256("BatchIntent(Intent[2]...[2] tree)Intent(bool isBuy,address buyToken,address sellToken,address maker,address solver,address source,uint16 feeBps,uint16 surplusBps,uint32 startTime,uint32 endTime,uint256 nonce,bool isPartiallyFillable,bool isSmartOrder,bool isIncentivized,bool isCriteriaOrder,uint256 tokenIdOrCriteria,uint128 amount,uint128 endAmount,uint16 startAmountBps,uint16 expectedAmountBps)")
        if (treeHeight == 1) {
            typeHash = 0xe2f9470ce56204b03b7f6a5da488bc405af34f9420fea7d23b9caa0e9f13b34b;
        } else if (treeHeight == 2) {
            typeHash = 0x38f007c7b676c4e3c06780a2eb36358363d4dbba803a413335dac32c672faf5c;
        } else if (treeHeight == 3) {
            typeHash = 0xaebed864141699427ffecf19db72b18a6519621259be5ad00bc0cd844551e7fb;
        } else if (treeHeight == 4) {
            typeHash = 0xb4f25ef2f5b34b8c0b2db30279b8b106d127c64b562153796fd3b9b826e08094;
        } else if (treeHeight == 5) {
            typeHash = 0xed14a836400793f5936eecd4130e39ee9d8d69c4815012477a72d0d8ccacb560;
        } else if (treeHeight == 6) {
            typeHash = 0xd51da1ce6fb4cad122d966c4939bfbe48df609c2321c0aa5ad45f30d93c5bce4;
        } else if (treeHeight == 7) {
            typeHash = 0x7f233ad630dc1877c45a371e9b3c2e9b0bf2d2a42d50f3ce4f6f548f50a4ce7b;
        } else if (treeHeight == 8) {
            typeHash = 0x075e03a4af0aeb0971b0a23187d89b336494d815e4007aed2a282b2ff023dea8;
        } else {
            revert MerkleTreeTooLarge();
        }
    }
}

// File: contracts/nft/MemswapAlphaNFT.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC721/ERC721.sol";

contract MemswapAlphaNFT is ERC721, Ownable {
    // --- Errors ---

    error Unauthorized();

    // --- Fields ---

    // Public

    string public baseTokenURI;
    string public contractURI;

    mapping(address => bool) public isAllowedToMint;

    // Private

    uint256 private nextTokenId;

    // --- Constructor ---

    constructor(
        address _owner,
        string memory _baseTokenURI,
        string memory _contractURI
    ) ERC721("Memswap Alpha NFT", "MEM") {
        baseTokenURI = _baseTokenURI;
        contractURI = _contractURI;

        _transferOwnership(_owner);
    }

    // --- Public methods ---

    function mint(address recipient) external {
        if (!isAllowedToMint[msg.sender]) {
            revert Unauthorized();
        }

        _mint(recipient, nextTokenId++);
    }

    // --- Owner methods ---

    function updateBaseTokenURI(
        string memory newBaseTokenURI
    ) external onlyOwner {
        baseTokenURI = newBaseTokenURI;
    }

    function updateContractURI(
        string memory newContractURI
    ) external onlyOwner {
        contractURI = newContractURI;
    }

    function setIsAllowedToMint(
        address[] calldata minters,
        bool[] calldata allowed
    ) external onlyOwner {
        unchecked {
            for (uint256 i; i < minters.length; i++) {
                isAllowedToMint[minters[i]] = allowed[i];
            }
        }
    }

    // --- Internal methods ---

    function _baseURI() internal view override returns (string memory) {
        return baseTokenURI;
    }
}

// File: contracts/solution/SolutionProxy.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721.sol";

import {MemswapERC20} from "../erc20/MemswapERC20.sol";
import {MemswapERC721} from "../erc721/MemswapERC721.sol";
import {PermitExecutor} from "../common/PermitExecutor.sol";

import {ISolutionERC20} from "../erc20/interfaces/ISolutionERC20.sol";
import {ISolutionERC721} from "../erc721/interfaces/ISolutionERC721.sol";

contract SolutionProxy is ISolutionERC20, ISolutionERC721 {
    // --- Structs ---

    struct Call {
        address to;
        bytes data;
        uint256 value;
    }

    // --- Errors ---

    error NotSupported();
    error Unauthorized();
    error UnsuccessfulCall();

    // --- Fields ---

    address public owner;
    address public memswapERC20;
    address public memswapERC721;

    // --- Constructor ---

    constructor(
        address ownerAddress,
        address memswapERC20Address,
        address memswapERC721Address
    ) {
        owner = ownerAddress;
        memswapERC20 = memswapERC20Address;
        memswapERC721 = memswapERC721Address;
    }

    // --- Fallback ---

    receive() external payable {}

    // --- Modifiers ---

    modifier restrictCaller(address caller) {
        if (msg.sender != caller) {
            revert Unauthorized();
        }

        _;
    }

    // --- Owner methods ---

    function transferOwnership(
        address newOwner
    ) external restrictCaller(owner) {
        owner = newOwner;
    }

    function updateMemswapERC20(
        address newMemswapERC20
    ) external restrictCaller(owner) {
        memswapERC20 = newMemswapERC20;
    }

    function updateMemswapERC721(
        address newMemswapERC721
    ) external restrictCaller(owner) {
        memswapERC721 = newMemswapERC721;
    }

    // --- Common ---

    function refund()
        external
        payable
        override(ISolutionERC20, ISolutionERC721)
    {
        makeCall(Call(owner, "", address(this).balance));
    }

    // --- ERC20 ---

    function solveERC20(
        MemswapERC20.Intent calldata intent,
        MemswapERC20.Solution calldata solution,
        PermitExecutor.Permit[] calldata permits
    ) external payable restrictCaller(owner) {
        MemswapERC20(payable(memswapERC20)).solve{value: msg.value}(
            intent,
            solution,
            permits
        );
    }

    function solveWithOnChainAuthorizationCheckERC20(
        MemswapERC20.Intent calldata intent,
        MemswapERC20.Solution calldata solution,
        PermitExecutor.Permit[] calldata permits
    ) external payable restrictCaller(owner) {
        MemswapERC20(payable(memswapERC20)).solveWithOnChainAuthorizationCheck{
            value: msg.value
        }(intent, solution, permits);
    }

    function solveWithSignatureAuthorizationCheckERC20(
        MemswapERC20.Intent calldata intent,
        MemswapERC20.Solution calldata solution,
        MemswapERC20.Authorization calldata auth,
        bytes calldata authSignature,
        PermitExecutor.Permit[] calldata permits
    ) external payable restrictCaller(owner) {
        MemswapERC20(payable(memswapERC20))
            .solveWithSignatureAuthorizationCheck{value: msg.value}(
            intent,
            solution,
            auth,
            authSignature,
            permits
        );
    }

    function callback(
        MemswapERC20.Intent memory intent,
        uint128 amountToFill,
        bytes memory data
    ) external override restrictCaller(memswapERC20) {
        (uint128 amountToExecute, Call[] memory calls) = abi.decode(
            data,
            (uint128, Call[])
        );

        // Make calls
        unchecked {
            uint256 callsLength = calls.length;
            for (uint256 i; i < callsLength; i++) {
                makeCall(calls[i]);
            }
        }

        if (intent.isBuy) {
            // Push outputs to maker
            bool outputETH = intent.buyToken == address(0);
            if (outputETH) {
                makeCall(Call(intent.maker, "", amountToFill));
            } else {
                IERC20(intent.buyToken).transfer(intent.maker, amountToFill);
            }

            uint256 amountLeft;

            // Take profits in sell token
            amountLeft = IERC20(intent.sellToken).balanceOf(address(this));
            if (amountLeft > 0) {
                IERC20(intent.sellToken).transfer(owner, amountLeft);
            }

            // Take profits in native token
            amountLeft = address(this).balance;
            if (amountLeft > 0) {
                makeCall(Call(owner, "", amountLeft));
            }
        } else {
            uint256 amountLeft;

            // Push outputs to maker
            bool outputETH = intent.buyToken == address(0);
            if (outputETH) {
                makeCall(Call(intent.maker, "", amountToExecute));

                // Take profits in native token
                amountLeft = address(this).balance;
                if (amountLeft > 0) {
                    makeCall(Call(owner, "", amountLeft));
                }
            } else {
                IERC20(intent.buyToken).transfer(intent.maker, amountToExecute);

                // Take profits in buy token
                amountLeft = IERC20(intent.buyToken).balanceOf(address(this));
                if (amountLeft > 0) {
                    IERC20(intent.buyToken).transfer(owner, amountLeft);
                }
            }
        }
    }

    // --- ERC721 ---

    function solveERC721(
        MemswapERC721.Intent calldata intent,
        MemswapERC721.Solution calldata solution,
        PermitExecutor.Permit[] calldata permits
    ) external payable restrictCaller(owner) {
        MemswapERC721(payable(memswapERC721)).solve{value: msg.value}(
            intent,
            solution,
            permits
        );
    }

    function solveWithOnChainAuthorizationCheckERC721(
        MemswapERC721.Intent calldata intent,
        MemswapERC721.Solution calldata solution,
        PermitExecutor.Permit[] calldata permits
    ) external payable restrictCaller(owner) {
        MemswapERC721(payable(memswapERC721))
            .solveWithOnChainAuthorizationCheck{value: msg.value}(
            intent,
            solution,
            permits
        );
    }

    function solveWithSignatureAuthorizationCheckERC721(
        MemswapERC721.Intent calldata intent,
        MemswapERC721.Solution calldata solution,
        MemswapERC721.Authorization calldata auth,
        bytes calldata authSignature,
        PermitExecutor.Permit[] calldata permits
    ) external payable restrictCaller(owner) {
        MemswapERC721(payable(memswapERC721))
            .solveWithSignatureAuthorizationCheck{value: msg.value}(
            intent,
            solution,
            auth,
            authSignature,
            permits
        );
    }

    function callback(
        MemswapERC721.Intent memory intent,
        MemswapERC721.TokenDetails[] memory,
        bytes memory data
    ) external override restrictCaller(memswapERC721) {
        Call[] memory calls = abi.decode(data, (Call[]));

        // Make calls
        unchecked {
            uint256 callsLength = calls.length;
            for (uint256 i; i < callsLength; i++) {
                makeCall(calls[i]);
            }
        }

        if (intent.isBuy) {
            uint256 amountLeft;

            // Take profits in sell token
            amountLeft = IERC20(intent.sellToken).balanceOf(address(this));
            if (amountLeft > 0) {
                IERC20(intent.sellToken).transfer(owner, amountLeft);
            }

            // Take profits in native token
            amountLeft = address(this).balance;
            if (amountLeft > 0) {
                makeCall(Call(owner, "", amountLeft));
            }
        } else {
            revert NotSupported();
        }
    }

    // --- Internal methods ---

    function makeCall(Call memory call) internal {
        (bool success, ) = call.to.call{value: call.value}(call.data);
        if (!success) {
            revert UnsuccessfulCall();
        }
    }
}