// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
import { IERC721Receiver } from "../interfaces/IERC721Receiver.sol";
import "./TransferHelperStructs.sol";
import { ConduitInterface } from "../interfaces/ConduitInterface.sol";
import {
    ConduitControllerInterface
} from "../interfaces/ConduitControllerInterface.sol";
import { Conduit } from "../conduit/Conduit.sol";
import { ConduitTransfer } from "../conduit/lib/ConduitStructs.sol";
import {
    TransferHelperInterface
} from "../interfaces/TransferHelperInterface.sol";
import { TransferHelperErrors } from "../interfaces/TransferHelperErrors.sol";
/**
 * @title TransferHelper
 * @author stephankmin, stuckinaboot, ryanio
 * @notice TransferHelper is a utility contract for transferring
 *         ERC20/ERC721/ERC1155 items in bulk to specific recipients.
 */
contract TransferHelper is TransferHelperInterface, TransferHelperErrors {
    // Allow for interaction with the conduit controller.
    ConduitControllerInterface internal immutable _CONDUIT_CONTROLLER;
    // Set conduit creation code and runtime code hashes as immutable arguments.
    bytes32 internal immutable _CONDUIT_CREATION_CODE_HASH;
    bytes32 internal immutable _CONDUIT_RUNTIME_CODE_HASH;
    /**
     * @dev Set the supplied conduit controller and retrieve its
     *      conduit creation code hash.
     *
     *
     * @param conduitController A contract that deploys conduits, or proxies
     *                          that may optionally be used to transfer approved
     *                          ERC20/721/1155 tokens.
     */
    constructor(address conduitController) {
        // Get the conduit creation code and runtime code hashes from the
        // supplied conduit controller and set them as an immutable.
        ConduitControllerInterface controller = ConduitControllerInterface(
            conduitController
        );
        (_CONDUIT_CREATION_CODE_HASH, _CONDUIT_RUNTIME_CODE_HASH) = controller
            .getConduitCodeHashes();
        // Set the supplied conduit controller as an immutable.
        _CONDUIT_CONTROLLER = controller;
    }
    /**
     * @notice Transfer multiple ERC20/ERC721/ERC1155 items to
     *         specified recipients.
     *
     * @param items      The items to transfer to an intended recipient.
     * @param conduitKey An optional conduit key referring to a conduit through
     *                   which the bulk transfer should occur.
     *
     * @return magicValue A value indicating that the transfers were successful.
     */
    function bulkTransfer(
        TransferHelperItemsWithRecipient[] calldata items,
        bytes32 conduitKey
    ) external override returns (bytes4 magicValue) {
        // Ensure that a conduit key has been supplied.
        if (conduitKey == bytes32(0)) {
            revert InvalidConduit(conduitKey, address(0));
        }
        // Use conduit derived from supplied conduit key to perform transfers.
        _performTransfersWithConduit(items, conduitKey);
        // Return a magic value indicating that the transfers were performed.
        magicValue = this.bulkTransfer.selector;
    }
    /**
     * @notice Perform multiple transfers to specified recipients via the
     *         conduit derived from the provided conduit key.
     *
     * @param transfers  The items to transfer.
     * @param conduitKey The conduit key referring to the conduit through
     *                   which the bulk transfer should occur.
     */
    function _performTransfersWithConduit(
        TransferHelperItemsWithRecipient[] calldata transfers,
        bytes32 conduitKey
    ) internal {
        // Retrieve total number of transfers and place on stack.
        uint256 numTransfers = transfers.length;
        // Derive the conduit address from the deployer, conduit key
        // and creation code hash.
        address conduit = address(
            uint160(
                uint256(
                    keccak256(
                        abi.encodePacked(
                            bytes1(0xff),
                            address(_CONDUIT_CONTROLLER),
                            conduitKey,
                            _CONDUIT_CREATION_CODE_HASH
                        )
                    )
                )
            )
        );
        // Declare a variable to store the sum of all items across transfers.
        uint256 sumOfItemsAcrossAllTransfers;
        // Skip overflow checks: all for loops are indexed starting at zero.
        unchecked {
            // Iterate over each transfer.
            for (uint256 i = 0; i < numTransfers; ++i) {
                // Retrieve the transfer in question.
                TransferHelperItemsWithRecipient calldata transfer = transfers[
                    i
                ];
                // Increment totalItems by the number of items in the transfer.
                sumOfItemsAcrossAllTransfers += transfer.items.length;
            }
        }
        // Declare a new array in memory with length totalItems to populate with
        // each conduit transfer.
        ConduitTransfer[] memory conduitTransfers = new ConduitTransfer[](
            sumOfItemsAcrossAllTransfers
        );
        // Declare an index for storing ConduitTransfers in conduitTransfers.
        uint256 itemIndex;
        // Skip overflow checks: all for loops are indexed starting at zero.
        unchecked {
            // Iterate over each transfer.
            for (uint256 i = 0; i < numTransfers; ++i) {
                // Retrieve the transfer in question.
                TransferHelperItemsWithRecipient calldata transfer = transfers[
                    i
                ];
                // Retrieve the items of the transfer in question.
                TransferHelperItem[] calldata transferItems = transfer.items;
                // Ensure recipient is not the zero address.
                _checkRecipientIsNotZeroAddress(transfer.recipient);
                // Create a boolean indicating whether validateERC721Receiver
                // is true and recipient is a contract.
                bool callERC721Receiver = transfer.validateERC721Receiver &&
                    transfer.recipient.code.length != 0;
                // Retrieve the total number of items in the transfer and
                // place on stack.
                uint256 numItemsInTransfer = transferItems.length;
                // Iterate over each item in the transfer to create a
                // corresponding ConduitTransfer.
                for (uint256 j = 0; j < numItemsInTransfer; ++j) {
                    // Retrieve the item from the transfer.
                    TransferHelperItem calldata item = transferItems[j];
                    if (item.itemType == ConduitItemType.ERC20) {
                        // Ensure that the identifier of an ERC20 token is 0.
                        if (item.identifier != 0) {
                            revert InvalidERC20Identifier();
                        }
                    }
                    // If the item is an ERC721 token and
                    // callERC721Receiver is true...
                    if (item.itemType == ConduitItemType.ERC721) {
                        if (callERC721Receiver) {
                            // Check if the recipient implements
                            // onERC721Received for the given tokenId.
                            _checkERC721Receiver(
                                conduit,
                                transfer.recipient,
                                item.identifier
                            );
                        }
                    }
                    // Create a ConduitTransfer corresponding to each
                    // TransferHelperItem.
                    conduitTransfers[itemIndex] = ConduitTransfer(
                        item.itemType,
                        item.token,
                        msg.sender,
                        transfer.recipient,
                        item.identifier,
                        item.amount
                    );
                    // Increment the index for storing ConduitTransfers.
                    ++itemIndex;
                }
            }
        }
        // Attempt the external call to transfer tokens via the derived conduit.
        try ConduitInterface(conduit).execute(conduitTransfers) returns (
            bytes4 conduitMagicValue
        ) {
            // Check if the value returned from the external call matches
            // the conduit `execute` selector.
            if (conduitMagicValue != ConduitInterface.execute.selector) {
                // If the external call fails, revert with the conduit key
                // and conduit address.
                revert InvalidConduit(conduitKey, conduit);
            }
        } catch Error(string memory reason) {
            // Catch reverts with a provided reason string and
            // revert with the reason, conduit key and conduit address.
            revert ConduitErrorRevertString(reason, conduitKey, conduit);
        } catch (bytes memory data) {
            // Conduits will throw a custom error when attempting to transfer
            // native token item types or an ERC721 item amount other than 1.
            // Bubble up these custom errors when encountered. Note that the
            // conduit itself will bubble up revert reasons from transfers as
            // well, meaning that these errors are not necessarily indicative of
            // an issue with the item type or amount in cases where the same
            // custom error signature is encountered during a conduit transfer.
            // Set initial value of first four bytes of revert data to the mask.
            bytes4 customErrorSelector = bytes4(0xffffffff);
            // Utilize assembly to read first four bytes (if present) directly.
            assembly {
                // Combine original mask with first four bytes of revert data.
                customErrorSelector := and(
                    mload(add(data, 0x20)), // Data begins after length offset.
                    customErrorSelector
                )
            }
            // Pass through the custom error in question if the revert data is
            // the correct length and matches an expected custom error selector.
            if (
                data.length == 4 &&
                (customErrorSelector == InvalidItemType.selector ||
                    customErrorSelector == InvalidERC721TransferAmount.selector)
            ) {
                // "Bubble up" the revert reason.
                assembly {
                    revert(add(data, 0x20), 0x04)
                }
            }
            // Catch all other reverts from the external call to the conduit and
            // include the conduit's raw revert reason as a data argument to a
            // new custom error.
            revert ConduitErrorRevertBytes(data, conduitKey, conduit);
        }
    }
    /**
     * @notice An internal function to check if a recipient address implements
     *         onERC721Received for a given tokenId. Note that this check does
     *         not adhere to the safe transfer specification and is only meant
     *         to provide an additional layer of assurance that the recipient
     *         can receive the tokens — any hooks or post-transfer checks will
     *         fail and the caller will be the transfer helper rather than the
     *         ERC721 contract. Note that the conduit is set as the operator, as
     *         it will be the caller once the transfer is performed.
     *
     * @param conduit   The conduit to provide as the operator when calling
     *                  onERC721Received.
     * @param recipient The ERC721 recipient on which to call onERC721Received.
     * @param tokenId   The ERC721 tokenId of the token being transferred.
     */
    function _checkERC721Receiver(
        address conduit,
        address recipient,
        uint256 tokenId
    ) internal {
        // Check if recipient can receive ERC721 tokens.
        try
            IERC721Receiver(recipient).onERC721Received(
                conduit,
                msg.sender,
                tokenId,
                ""
            )
        returns (bytes4 selector) {
            // Check if onERC721Received selector is valid.
            if (selector != IERC721Receiver.onERC721Received.selector) {
                // Revert if recipient cannot accept
                // ERC721 tokens.
                revert InvalidERC721Recipient(recipient);
            }
        } catch (bytes memory data) {
            // "Bubble up" recipient's revert reason.
            revert ERC721ReceiverErrorRevertBytes(
                data,
                recipient,
                msg.sender,
                tokenId
            );
        } catch Error(string memory reason) {
            // "Bubble up" recipient's revert reason.
            revert ERC721ReceiverErrorRevertString(
                reason,
                recipient,
                msg.sender,
                tokenId
            );
        }
    }
    /**
     * @notice An internal function that reverts if the passed-in recipient
     *         is the zero address.
     *
     * @param recipient The recipient on which to perform the check.
     */
    function _checkRecipientIsNotZeroAddress(address recipient) internal pure {
        // Revert if the recipient is the zero address.
        if (recipient == address(0x0)) {
            revert RecipientCannotBeZeroAddress();
        }
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
interface IERC721Receiver {
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
import { ConduitItemType } from "../conduit/lib/ConduitEnums.sol";
/**
 * @dev A TransferHelperItem specifies the itemType (ERC20/ERC721/ERC1155),
 *      token address, token identifier, and amount of the token to be
 *      transferred via the TransferHelper. For ERC20 tokens, identifier
 *      must be 0. For ERC721 tokens, amount must be 1.
 */
struct TransferHelperItem {
    ConduitItemType itemType;
    address token;
    uint256 identifier;
    uint256 amount;
}
/**
 * @dev A TransferHelperItemsWithRecipient specifies the tokens to transfer
 *      via the TransferHelper, their intended recipient, and a boolean flag
 *      indicating whether onERC721Received should be called on a recipient
 *      contract.
 */
struct TransferHelperItemsWithRecipient {
    TransferHelperItem[] items;
    address recipient;
    bool validateERC721Receiver;
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
import {
    ConduitTransfer,
    ConduitBatch1155Transfer
} from "../conduit/lib/ConduitStructs.sol";
/**
 * @title ConduitInterface
 * @author 0age
 * @notice ConduitInterface contains all external function interfaces, events,
 *         and errors for conduit contracts.
 */
interface ConduitInterface {
    /**
     * @dev Revert with an error when attempting to execute transfers using a
     *      caller that does not have an open channel.
     */
    error ChannelClosed(address channel);
    /**
     * @dev Revert with an error when attempting to update a channel to the
     *      current status of that channel.
     */
    error ChannelStatusAlreadySet(address channel, bool isOpen);
    /**
     * @dev Revert with an error when attempting to execute a transfer for an
     *      item that does not have an ERC20/721/1155 item type.
     */
    error InvalidItemType();
    /**
     * @dev Revert with an error when attempting to update the status of a
     *      channel from a caller that is not the conduit controller.
     */
    error InvalidController();
    /**
     * @dev Emit an event whenever a channel is opened or closed.
     *
     * @param channel The channel that has been updated.
     * @param open    A boolean indicating whether the conduit is open or not.
     */
    event ChannelUpdated(address indexed channel, bool open);
    /**
     * @notice Execute a sequence of ERC20/721/1155 transfers. Only a caller
     *         with an open channel can call this function.
     *
     * @param transfers The ERC20/721/1155 transfers to perform.
     *
     * @return magicValue A magic value indicating that the transfers were
     *                    performed successfully.
     */
    function execute(ConduitTransfer[] calldata transfers)
        external
        returns (bytes4 magicValue);
    /**
     * @notice Execute a sequence of batch 1155 transfers. Only a caller with an
     *         open channel can call this function.
     *
     * @param batch1155Transfers The 1155 batch transfers to perform.
     *
     * @return magicValue A magic value indicating that the transfers were
     *                    performed successfully.
     */
    function executeBatch1155(
        ConduitBatch1155Transfer[] calldata batch1155Transfers
    ) external returns (bytes4 magicValue);
    /**
     * @notice Execute a sequence of transfers, both single and batch 1155. Only
     *         a caller with an open channel can call this function.
     *
     * @param standardTransfers  The ERC20/721/1155 transfers to perform.
     * @param batch1155Transfers The 1155 batch transfers to perform.
     *
     * @return magicValue A magic value indicating that the transfers were
     *                    performed successfully.
     */
    function executeWithBatch1155(
        ConduitTransfer[] calldata standardTransfers,
        ConduitBatch1155Transfer[] calldata batch1155Transfers
    ) external returns (bytes4 magicValue);
    /**
     * @notice Open or close a given channel. Only callable by the controller.
     *
     * @param channel The channel to open or close.
     * @param isOpen  The status of the channel (either open or closed).
     */
    function updateChannel(address channel, bool isOpen) external;
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
/**
 * @title ConduitControllerInterface
 * @author 0age
 * @notice ConduitControllerInterface contains all external function interfaces,
 *         structs, events, and errors for the conduit controller.
 */
interface ConduitControllerInterface {
    /**
     * @dev Track the conduit key, current owner, new potential owner, and open
     *      channels for each deployed conduit.
     */
    struct ConduitProperties {
        bytes32 key;
        address owner;
        address potentialOwner;
        address[] channels;
        mapping(address => uint256) channelIndexesPlusOne;
    }
    /**
     * @dev Emit an event whenever a new conduit is created.
     *
     * @param conduit    The newly created conduit.
     * @param conduitKey The conduit key used to create the new conduit.
     */
    event NewConduit(address conduit, bytes32 conduitKey);
    /**
     * @dev Emit an event whenever conduit ownership is transferred.
     *
     * @param conduit       The conduit for which ownership has been
     *                      transferred.
     * @param previousOwner The previous owner of the conduit.
     * @param newOwner      The new owner of the conduit.
     */
    event OwnershipTransferred(
        address indexed conduit,
        address indexed previousOwner,
        address indexed newOwner
    );
    /**
     * @dev Emit an event whenever a conduit owner registers a new potential
     *      owner for that conduit.
     *
     * @param newPotentialOwner The new potential owner of the conduit.
     */
    event PotentialOwnerUpdated(address indexed newPotentialOwner);
    /**
     * @dev Revert with an error when attempting to create a new conduit using a
     *      conduit key where the first twenty bytes of the key do not match the
     *      address of the caller.
     */
    error InvalidCreator();
    /**
     * @dev Revert with an error when attempting to create a new conduit when no
     *      initial owner address is supplied.
     */
    error InvalidInitialOwner();
    /**
     * @dev Revert with an error when attempting to set a new potential owner
     *      that is already set.
     */
    error NewPotentialOwnerAlreadySet(
        address conduit,
        address newPotentialOwner
    );
    /**
     * @dev Revert with an error when attempting to cancel ownership transfer
     *      when no new potential owner is currently set.
     */
    error NoPotentialOwnerCurrentlySet(address conduit);
    /**
     * @dev Revert with an error when attempting to interact with a conduit that
     *      does not yet exist.
     */
    error NoConduit();
    /**
     * @dev Revert with an error when attempting to create a conduit that
     *      already exists.
     */
    error ConduitAlreadyExists(address conduit);
    /**
     * @dev Revert with an error when attempting to update channels or transfer
     *      ownership of a conduit when the caller is not the owner of the
     *      conduit in question.
     */
    error CallerIsNotOwner(address conduit);
    /**
     * @dev Revert with an error when attempting to register a new potential
     *      owner and supplying the null address.
     */
    error NewPotentialOwnerIsZeroAddress(address conduit);
    /**
     * @dev Revert with an error when attempting to claim ownership of a conduit
     *      with a caller that is not the current potential owner for the
     *      conduit in question.
     */
    error CallerIsNotNewPotentialOwner(address conduit);
    /**
     * @dev Revert with an error when attempting to retrieve a channel using an
     *      index that is out of range.
     */
    error ChannelOutOfRange(address conduit);
    /**
     * @notice Deploy a new conduit using a supplied conduit key and assigning
     *         an initial owner for the deployed conduit. Note that the first
     *         twenty bytes of the supplied conduit key must match the caller
     *         and that a new conduit cannot be created if one has already been
     *         deployed using the same conduit key.
     *
     * @param conduitKey   The conduit key used to deploy the conduit. Note that
     *                     the first twenty bytes of the conduit key must match
     *                     the caller of this contract.
     * @param initialOwner The initial owner to set for the new conduit.
     *
     * @return conduit The address of the newly deployed conduit.
     */
    function createConduit(bytes32 conduitKey, address initialOwner)
        external
        returns (address conduit);
    /**
     * @notice Open or close a channel on a given conduit, thereby allowing the
     *         specified account to execute transfers against that conduit.
     *         Extreme care must be taken when updating channels, as malicious
     *         or vulnerable channels can transfer any ERC20, ERC721 and ERC1155
     *         tokens where the token holder has granted the conduit approval.
     *         Only the owner of the conduit in question may call this function.
     *
     * @param conduit The conduit for which to open or close the channel.
     * @param channel The channel to open or close on the conduit.
     * @param isOpen  A boolean indicating whether to open or close the channel.
     */
    function updateChannel(
        address conduit,
        address channel,
        bool isOpen
    ) external;
    /**
     * @notice Initiate conduit ownership transfer by assigning a new potential
     *         owner for the given conduit. Once set, the new potential owner
     *         may call `acceptOwnership` to claim ownership of the conduit.
     *         Only the owner of the conduit in question may call this function.
     *
     * @param conduit The conduit for which to initiate ownership transfer.
     * @param newPotentialOwner The new potential owner of the conduit.
     */
    function transferOwnership(address conduit, address newPotentialOwner)
        external;
    /**
     * @notice Clear the currently set potential owner, if any, from a conduit.
     *         Only the owner of the conduit in question may call this function.
     *
     * @param conduit The conduit for which to cancel ownership transfer.
     */
    function cancelOwnershipTransfer(address conduit) external;
    /**
     * @notice Accept ownership of a supplied conduit. Only accounts that the
     *         current owner has set as the new potential owner may call this
     *         function.
     *
     * @param conduit The conduit for which to accept ownership.
     */
    function acceptOwnership(address conduit) external;
    /**
     * @notice Retrieve the current owner of a deployed conduit.
     *
     * @param conduit The conduit for which to retrieve the associated owner.
     *
     * @return owner The owner of the supplied conduit.
     */
    function ownerOf(address conduit) external view returns (address owner);
    /**
     * @notice Retrieve the conduit key for a deployed conduit via reverse
     *         lookup.
     *
     * @param conduit The conduit for which to retrieve the associated conduit
     *                key.
     *
     * @return conduitKey The conduit key used to deploy the supplied conduit.
     */
    function getKey(address conduit) external view returns (bytes32 conduitKey);
    /**
     * @notice Derive the conduit associated with a given conduit key and
     *         determine whether that conduit exists (i.e. whether it has been
     *         deployed).
     *
     * @param conduitKey The conduit key used to derive the conduit.
     *
     * @return conduit The derived address of the conduit.
     * @return exists  A boolean indicating whether the derived conduit has been
     *                 deployed or not.
     */
    function getConduit(bytes32 conduitKey)
        external
        view
        returns (address conduit, bool exists);
    /**
     * @notice Retrieve the potential owner, if any, for a given conduit. The
     *         current owner may set a new potential owner via
     *         `transferOwnership` and that owner may then accept ownership of
     *         the conduit in question via `acceptOwnership`.
     *
     * @param conduit The conduit for which to retrieve the potential owner.
     *
     * @return potentialOwner The potential owner, if any, for the conduit.
     */
    function getPotentialOwner(address conduit)
        external
        view
        returns (address potentialOwner);
    /**
     * @notice Retrieve the status (either open or closed) of a given channel on
     *         a conduit.
     *
     * @param conduit The conduit for which to retrieve the channel status.
     * @param channel The channel for which to retrieve the status.
     *
     * @return isOpen The status of the channel on the given conduit.
     */
    function getChannelStatus(address conduit, address channel)
        external
        view
        returns (bool isOpen);
    /**
     * @notice Retrieve the total number of open channels for a given conduit.
     *
     * @param conduit The conduit for which to retrieve the total channel count.
     *
     * @return totalChannels The total number of open channels for the conduit.
     */
    function getTotalChannels(address conduit)
        external
        view
        returns (uint256 totalChannels);
    /**
     * @notice Retrieve an open channel at a specific index for a given conduit.
     *         Note that the index of a channel can change as a result of other
     *         channels being closed on the conduit.
     *
     * @param conduit      The conduit for which to retrieve the open channel.
     * @param channelIndex The index of the channel in question.
     *
     * @return channel The open channel, if any, at the specified channel index.
     */
    function getChannel(address conduit, uint256 channelIndex)
        external
        view
        returns (address channel);
    /**
     * @notice Retrieve all open channels for a given conduit. Note that calling
     *         this function for a conduit with many channels will revert with
     *         an out-of-gas error.
     *
     * @param conduit The conduit for which to retrieve open channels.
     *
     * @return channels An array of open channels on the given conduit.
     */
    function getChannels(address conduit)
        external
        view
        returns (address[] memory channels);
    /**
     * @dev Retrieve the conduit creation code and runtime code hashes.
     */
    function getConduitCodeHashes()
        external
        view
        returns (bytes32 creationCodeHash, bytes32 runtimeCodeHash);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
import { ConduitInterface } from "../interfaces/ConduitInterface.sol";
import { ConduitItemType } from "./lib/ConduitEnums.sol";
import { TokenTransferrer } from "../lib/TokenTransferrer.sol";
import {
    ConduitTransfer,
    ConduitBatch1155Transfer
} from "./lib/ConduitStructs.sol";
import "./lib/ConduitConstants.sol";
/**
 * @title Conduit
 * @author 0age
 * @notice This contract serves as an originator for "proxied" transfers. Each
 *         conduit is deployed and controlled by a "conduit controller" that can
 *         add and remove "channels" or contracts that can instruct the conduit
 *         to transfer approved ERC20/721/1155 tokens. *IMPORTANT NOTE: each
 *         conduit has an owner that can arbitrarily add or remove channels, and
 *         a malicious or negligent owner can add a channel that allows for any
 *         approved ERC20/721/1155 tokens to be taken immediately — be extremely
 *         cautious with what conduits you give token approvals to!*
 */
contract Conduit is ConduitInterface, TokenTransferrer {
    // Set deployer as an immutable controller that can update channel statuses.
    address private immutable _controller;
    // Track the status of each channel.
    mapping(address => bool) private _channels;
    /**
     * @notice Ensure that the caller is currently registered as an open channel
     *         on the conduit.
     */
    modifier onlyOpenChannel() {
        // Utilize assembly to access channel storage mapping directly.
        assembly {
            // Write the caller to scratch space.
            mstore(ChannelKey_channel_ptr, caller())
            // Write the storage slot for _channels to scratch space.
            mstore(ChannelKey_slot_ptr, _channels.slot)
            // Derive the position in storage of _channels[msg.sender]
            // and check if the stored value is zero.
            if iszero(
                sload(keccak256(ChannelKey_channel_ptr, ChannelKey_length))
            ) {
                // The caller is not an open channel; revert with
                // ChannelClosed(caller). First, set error signature in memory.
                mstore(ChannelClosed_error_ptr, ChannelClosed_error_signature)
                // Next, set the caller as the argument.
                mstore(ChannelClosed_channel_ptr, caller())
                // Finally, revert, returning full custom error with argument.
                revert(ChannelClosed_error_ptr, ChannelClosed_error_length)
            }
        }
        // Continue with function execution.
        _;
    }
    /**
     * @notice In the constructor, set the deployer as the controller.
     */
    constructor() {
        // Set the deployer as the controller.
        _controller = msg.sender;
    }
    /**
     * @notice Execute a sequence of ERC20/721/1155 transfers. Only a caller
     *         with an open channel can call this function. Note that channels
     *         are expected to implement reentrancy protection if desired, and
     *         that cross-channel reentrancy may be possible if the conduit has
     *         multiple open channels at once. Also note that channels are
     *         expected to implement checks against transferring any zero-amount
     *         items if that constraint is desired.
     *
     * @param transfers The ERC20/721/1155 transfers to perform.
     *
     * @return magicValue A magic value indicating that the transfers were
     *                    performed successfully.
     */
    function execute(ConduitTransfer[] calldata transfers)
        external
        override
        onlyOpenChannel
        returns (bytes4 magicValue)
    {
        // Retrieve the total number of transfers and place on the stack.
        uint256 totalStandardTransfers = transfers.length;
        // Iterate over each transfer.
        for (uint256 i = 0; i < totalStandardTransfers; ) {
            // Retrieve the transfer in question and perform the transfer.
            _transfer(transfers[i]);
            // Skip overflow check as for loop is indexed starting at zero.
            unchecked {
                ++i;
            }
        }
        // Return a magic value indicating that the transfers were performed.
        magicValue = this.execute.selector;
    }
    /**
     * @notice Execute a sequence of batch 1155 item transfers. Only a caller
     *         with an open channel can call this function. Note that channels
     *         are expected to implement reentrancy protection if desired, and
     *         that cross-channel reentrancy may be possible if the conduit has
     *         multiple open channels at once. Also note that channels are
     *         expected to implement checks against transferring any zero-amount
     *         items if that constraint is desired.
     *
     * @param batchTransfers The 1155 batch item transfers to perform.
     *
     * @return magicValue A magic value indicating that the item transfers were
     *                    performed successfully.
     */
    function executeBatch1155(
        ConduitBatch1155Transfer[] calldata batchTransfers
    ) external override onlyOpenChannel returns (bytes4 magicValue) {
        // Perform 1155 batch transfers. Note that memory should be considered
        // entirely corrupted from this point forward.
        _performERC1155BatchTransfers(batchTransfers);
        // Return a magic value indicating that the transfers were performed.
        magicValue = this.executeBatch1155.selector;
    }
    /**
     * @notice Execute a sequence of transfers, both single ERC20/721/1155 item
     *         transfers as well as batch 1155 item transfers. Only a caller
     *         with an open channel can call this function. Note that channels
     *         are expected to implement reentrancy protection if desired, and
     *         that cross-channel reentrancy may be possible if the conduit has
     *         multiple open channels at once. Also note that channels are
     *         expected to implement checks against transferring any zero-amount
     *         items if that constraint is desired.
     *
     * @param standardTransfers The ERC20/721/1155 item transfers to perform.
     * @param batchTransfers    The 1155 batch item transfers to perform.
     *
     * @return magicValue A magic value indicating that the item transfers were
     *                    performed successfully.
     */
    function executeWithBatch1155(
        ConduitTransfer[] calldata standardTransfers,
        ConduitBatch1155Transfer[] calldata batchTransfers
    ) external override onlyOpenChannel returns (bytes4 magicValue) {
        // Retrieve the total number of transfers and place on the stack.
        uint256 totalStandardTransfers = standardTransfers.length;
        // Iterate over each standard transfer.
        for (uint256 i = 0; i < totalStandardTransfers; ) {
            // Retrieve the transfer in question and perform the transfer.
            _transfer(standardTransfers[i]);
            // Skip overflow check as for loop is indexed starting at zero.
            unchecked {
                ++i;
            }
        }
        // Perform 1155 batch transfers. Note that memory should be considered
        // entirely corrupted from this point forward aside from the free memory
        // pointer having the default value.
        _performERC1155BatchTransfers(batchTransfers);
        // Return a magic value indicating that the transfers were performed.
        magicValue = this.executeWithBatch1155.selector;
    }
    /**
     * @notice Open or close a given channel. Only callable by the controller.
     *
     * @param channel The channel to open or close.
     * @param isOpen  The status of the channel (either open or closed).
     */
    function updateChannel(address channel, bool isOpen) external override {
        // Ensure that the caller is the controller of this contract.
        if (msg.sender != _controller) {
            revert InvalidController();
        }
        // Ensure that the channel does not already have the indicated status.
        if (_channels[channel] == isOpen) {
            revert ChannelStatusAlreadySet(channel, isOpen);
        }
        // Update the status of the channel.
        _channels[channel] = isOpen;
        // Emit a corresponding event.
        emit ChannelUpdated(channel, isOpen);
    }
    /**
     * @dev Internal function to transfer a given ERC20/721/1155 item. Note that
     *      channels are expected to implement checks against transferring any
     *      zero-amount items if that constraint is desired.
     *
     * @param item The ERC20/721/1155 item to transfer.
     */
    function _transfer(ConduitTransfer calldata item) internal {
        // Determine the transfer method based on the respective item type.
        if (item.itemType == ConduitItemType.ERC20) {
            // Transfer ERC20 token. Note that item.identifier is ignored and
            // therefore ERC20 transfer items are potentially malleable — this
            // check should be performed by the calling channel if a constraint
            // on item malleability is desired.
            _performERC20Transfer(item.token, item.from, item.to, item.amount);
        } else if (item.itemType == ConduitItemType.ERC721) {
            // Ensure that exactly one 721 item is being transferred.
            if (item.amount != 1) {
                revert InvalidERC721TransferAmount();
            }
            // Transfer ERC721 token.
            _performERC721Transfer(
                item.token,
                item.from,
                item.to,
                item.identifier
            );
        } else if (item.itemType == ConduitItemType.ERC1155) {
            // Transfer ERC1155 token.
            _performERC1155Transfer(
                item.token,
                item.from,
                item.to,
                item.identifier,
                item.amount
            );
        } else {
            // Throw with an error.
            revert InvalidItemType();
        }
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
import { ConduitItemType } from "./ConduitEnums.sol";
struct ConduitTransfer {
    ConduitItemType itemType;
    address token;
    address from;
    address to;
    uint256 identifier;
    uint256 amount;
}
struct ConduitBatch1155Transfer {
    address token;
    address from;
    address to;
    uint256[] ids;
    uint256[] amounts;
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
import {
    TransferHelperItem,
    TransferHelperItemsWithRecipient
} from "../helpers/TransferHelperStructs.sol";
interface TransferHelperInterface {
    /**
     * @notice Transfer multiple items to a single recipient.
     *
     * @param items The items to transfer.
     * @param conduitKey  The key of the conduit performing the bulk transfer.
     */
    function bulkTransfer(
        TransferHelperItemsWithRecipient[] calldata items,
        bytes32 conduitKey
    ) external returns (bytes4);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
/**
 * @title TransferHelperErrors
 */
interface TransferHelperErrors {
    /**
     * @dev Revert with an error when attempting to execute transfers with a
     *      NATIVE itemType.
     */
    error InvalidItemType();
    /**
     * @dev Revert with an error when an ERC721 transfer with amount other than
     *      one is attempted.
     */
    error InvalidERC721TransferAmount();
    /**
     * @dev Revert with an error when attempting to execute an ERC721 transfer
     *      to an invalid recipient.
     */
    error InvalidERC721Recipient(address recipient);
    /**
     * @dev Revert with an error when a call to a ERC721 receiver reverts with
     *      bytes data.
     */
    error ERC721ReceiverErrorRevertBytes(
        bytes reason,
        address receiver,
        address sender,
        uint256 identifier
    );
    /**
     * @dev Revert with an error when a call to a ERC721 receiver reverts with
     *      string reason.
     */
    error ERC721ReceiverErrorRevertString(
        string reason,
        address receiver,
        address sender,
        uint256 identifier
    );
    /**
     * @dev Revert with an error when an ERC20 token has an invalid identifier.
     */
    error InvalidERC20Identifier();
    /**
     * @dev Revert with an error if the recipient is the zero address.
     */
    error RecipientCannotBeZeroAddress();
    /**
     * @dev Revert with an error when attempting to fill an order referencing an
     *      invalid conduit (i.e. one that has not been deployed).
     */
    error InvalidConduit(bytes32 conduitKey, address conduit);
    /**
     * @dev Revert with an error when a call to a conduit reverts with a
     *      reason string.
     */
    error ConduitErrorRevertString(
        string reason,
        bytes32 conduitKey,
        address conduit
    );
    /**
     * @dev Revert with an error when a call to a conduit reverts with bytes
     *      data.
     */
    error ConduitErrorRevertBytes(
        bytes reason,
        bytes32 conduitKey,
        address conduit
    );
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
enum ConduitItemType {
    NATIVE, // unused
    ERC20,
    ERC721,
    ERC1155
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
import "./TokenTransferrerConstants.sol";
import {
    TokenTransferrerErrors
} from "../interfaces/TokenTransferrerErrors.sol";
import { ConduitBatch1155Transfer } from "../conduit/lib/ConduitStructs.sol";
/**
 * @title TokenTransferrer
 * @author 0age
 * @custom:coauthor d1ll0n
 * @custom:coauthor transmissions11
 * @notice TokenTransferrer is a library for performing optimized ERC20, ERC721,
 *         ERC1155, and batch ERC1155 transfers, used by both Seaport as well as
 *         by conduits deployed by the ConduitController. Use great caution when
 *         considering these functions for use in other codebases, as there are
 *         significant side effects and edge cases that need to be thoroughly
 *         understood and carefully addressed.
 */
contract TokenTransferrer is TokenTransferrerErrors {
    /**
     * @dev Internal function to transfer ERC20 tokens from a given originator
     *      to a given recipient. Sufficient approvals must be set on the
     *      contract performing the transfer.
     *
     * @param token      The ERC20 token to transfer.
     * @param from       The originator of the transfer.
     * @param to         The recipient of the transfer.
     * @param amount     The amount to transfer.
     */
    function _performERC20Transfer(
        address token,
        address from,
        address to,
        uint256 amount
    ) internal {
        // Utilize assembly to perform an optimized ERC20 token transfer.
        assembly {
            // The free memory pointer memory slot will be used when populating
            // call data for the transfer; read the value and restore it later.
            let memPointer := mload(FreeMemoryPointerSlot)
            // Write call data into memory, starting with function selector.
            mstore(ERC20_transferFrom_sig_ptr, ERC20_transferFrom_signature)
            mstore(ERC20_transferFrom_from_ptr, from)
            mstore(ERC20_transferFrom_to_ptr, to)
            mstore(ERC20_transferFrom_amount_ptr, amount)
            // Make call & copy up to 32 bytes of return data to scratch space.
            // Scratch space does not need to be cleared ahead of time, as the
            // subsequent check will ensure that either at least a full word of
            // return data is received (in which case it will be overwritten) or
            // that no data is received (in which case scratch space will be
            // ignored) on a successful call to the given token.
            let callStatus := call(
                gas(),
                token,
                0,
                ERC20_transferFrom_sig_ptr,
                ERC20_transferFrom_length,
                0,
                OneWord
            )
            // Determine whether transfer was successful using status & result.
            let success := and(
                // Set success to whether the call reverted, if not check it
                // either returned exactly 1 (can't just be non-zero data), or
                // had no return data.
                or(
                    and(eq(mload(0), 1), gt(returndatasize(), 31)),
                    iszero(returndatasize())
                ),
                callStatus
            )
            // Handle cases where either the transfer failed or no data was
            // returned. Group these, as most transfers will succeed with data.
            // Equivalent to `or(iszero(success), iszero(returndatasize()))`
            // but after it's inverted for JUMPI this expression is cheaper.
            if iszero(and(success, iszero(iszero(returndatasize())))) {
                // If the token has no code or the transfer failed: Equivalent
                // to `or(iszero(success), iszero(extcodesize(token)))` but
                // after it's inverted for JUMPI this expression is cheaper.
                if iszero(and(iszero(iszero(extcodesize(token))), success)) {
                    // If the transfer failed:
                    if iszero(success) {
                        // If it was due to a revert:
                        if iszero(callStatus) {
                            // If it returned a message, bubble it up as long as
                            // sufficient gas remains to do so:
                            if returndatasize() {
                                // Ensure that sufficient gas is available to
                                // copy returndata while expanding memory where
                                // necessary. Start by computing the word size
                                // of returndata and allocated memory. Round up
                                // to the nearest full word.
                                let returnDataWords := div(
                                    add(returndatasize(), AlmostOneWord),
                                    OneWord
                                )
                                // Note: use the free memory pointer in place of
                                // msize() to work around a Yul warning that
                                // prevents accessing msize directly when the IR
                                // pipeline is activated.
                                let msizeWords := div(memPointer, OneWord)
                                // Next, compute the cost of the returndatacopy.
                                let cost := mul(CostPerWord, returnDataWords)
                                // Then, compute cost of new memory allocation.
                                if gt(returnDataWords, msizeWords) {
                                    cost := add(
                                        cost,
                                        add(
                                            mul(
                                                sub(
                                                    returnDataWords,
                                                    msizeWords
                                                ),
                                                CostPerWord
                                            ),
                                            div(
                                                sub(
                                                    mul(
                                                        returnDataWords,
                                                        returnDataWords
                                                    ),
                                                    mul(msizeWords, msizeWords)
                                                ),
                                                MemoryExpansionCoefficient
                                            )
                                        )
                                    )
                                }
                                // Finally, add a small constant and compare to
                                // gas remaining; bubble up the revert data if
                                // enough gas is still available.
                                if lt(add(cost, ExtraGasBuffer), gas()) {
                                    // Copy returndata to memory; overwrite
                                    // existing memory.
                                    returndatacopy(0, 0, returndatasize())
                                    // Revert, specifying memory region with
                                    // copied returndata.
                                    revert(0, returndatasize())
                                }
                            }
                            // Otherwise revert with a generic error message.
                            mstore(
                                TokenTransferGenericFailure_error_sig_ptr,
                                TokenTransferGenericFailure_error_signature
                            )
                            mstore(
                                TokenTransferGenericFailure_error_token_ptr,
                                token
                            )
                            mstore(
                                TokenTransferGenericFailure_error_from_ptr,
                                from
                            )
                            mstore(TokenTransferGenericFailure_error_to_ptr, to)
                            mstore(TokenTransferGenericFailure_error_id_ptr, 0)
                            mstore(
                                TokenTransferGenericFailure_error_amount_ptr,
                                amount
                            )
                            revert(
                                TokenTransferGenericFailure_error_sig_ptr,
                                TokenTransferGenericFailure_error_length
                            )
                        }
                        // Otherwise revert with a message about the token
                        // returning false or non-compliant return values.
                        mstore(
                            BadReturnValueFromERC20OnTransfer_error_sig_ptr,
                            BadReturnValueFromERC20OnTransfer_error_signature
                        )
                        mstore(
                            BadReturnValueFromERC20OnTransfer_error_token_ptr,
                            token
                        )
                        mstore(
                            BadReturnValueFromERC20OnTransfer_error_from_ptr,
                            from
                        )
                        mstore(
                            BadReturnValueFromERC20OnTransfer_error_to_ptr,
                            to
                        )
                        mstore(
                            BadReturnValueFromERC20OnTransfer_error_amount_ptr,
                            amount
                        )
                        revert(
                            BadReturnValueFromERC20OnTransfer_error_sig_ptr,
                            BadReturnValueFromERC20OnTransfer_error_length
                        )
                    }
                    // Otherwise, revert with error about token not having code:
                    mstore(NoContract_error_sig_ptr, NoContract_error_signature)
                    mstore(NoContract_error_token_ptr, token)
                    revert(NoContract_error_sig_ptr, NoContract_error_length)
                }
                // Otherwise, the token just returned no data despite the call
                // having succeeded; no need to optimize for this as it's not
                // technically ERC20 compliant.
            }
            // Restore the original free memory pointer.
            mstore(FreeMemoryPointerSlot, memPointer)
            // Restore the zero slot to zero.
            mstore(ZeroSlot, 0)
        }
    }
    /**
     * @dev Internal function to transfer an ERC721 token from a given
     *      originator to a given recipient. Sufficient approvals must be set on
     *      the contract performing the transfer. Note that this function does
     *      not check whether the receiver can accept the ERC721 token (i.e. it
     *      does not use `safeTransferFrom`).
     *
     * @param token      The ERC721 token to transfer.
     * @param from       The originator of the transfer.
     * @param to         The recipient of the transfer.
     * @param identifier The tokenId to transfer.
     */
    function _performERC721Transfer(
        address token,
        address from,
        address to,
        uint256 identifier
    ) internal {
        // Utilize assembly to perform an optimized ERC721 token transfer.
        assembly {
            // If the token has no code, revert.
            if iszero(extcodesize(token)) {
                mstore(NoContract_error_sig_ptr, NoContract_error_signature)
                mstore(NoContract_error_token_ptr, token)
                revert(NoContract_error_sig_ptr, NoContract_error_length)
            }
            // The free memory pointer memory slot will be used when populating
            // call data for the transfer; read the value and restore it later.
            let memPointer := mload(FreeMemoryPointerSlot)
            // Write call data to memory starting with function selector.
            mstore(ERC721_transferFrom_sig_ptr, ERC721_transferFrom_signature)
            mstore(ERC721_transferFrom_from_ptr, from)
            mstore(ERC721_transferFrom_to_ptr, to)
            mstore(ERC721_transferFrom_id_ptr, identifier)
            // Perform the call, ignoring return data.
            let success := call(
                gas(),
                token,
                0,
                ERC721_transferFrom_sig_ptr,
                ERC721_transferFrom_length,
                0,
                0
            )
            // If the transfer reverted:
            if iszero(success) {
                // If it returned a message, bubble it up as long as sufficient
                // gas remains to do so:
                if returndatasize() {
                    // Ensure that sufficient gas is available to copy
                    // returndata while expanding memory where necessary. Start
                    // by computing word size of returndata & allocated memory.
                    // Round up to the nearest full word.
                    let returnDataWords := div(
                        add(returndatasize(), AlmostOneWord),
                        OneWord
                    )
                    // Note: use the free memory pointer in place of msize() to
                    // work around a Yul warning that prevents accessing msize
                    // directly when the IR pipeline is activated.
                    let msizeWords := div(memPointer, OneWord)
                    // Next, compute the cost of the returndatacopy.
                    let cost := mul(CostPerWord, returnDataWords)
                    // Then, compute cost of new memory allocation.
                    if gt(returnDataWords, msizeWords) {
                        cost := add(
                            cost,
                            add(
                                mul(
                                    sub(returnDataWords, msizeWords),
                                    CostPerWord
                                ),
                                div(
                                    sub(
                                        mul(returnDataWords, returnDataWords),
                                        mul(msizeWords, msizeWords)
                                    ),
                                    MemoryExpansionCoefficient
                                )
                            )
                        )
                    }
                    // Finally, add a small constant and compare to gas
                    // remaining; bubble up the revert data if enough gas is
                    // still available.
                    if lt(add(cost, ExtraGasBuffer), gas()) {
                        // Copy returndata to memory; overwrite existing memory.
                        returndatacopy(0, 0, returndatasize())
                        // Revert, giving memory region with copied returndata.
                        revert(0, returndatasize())
                    }
                }
                // Otherwise revert with a generic error message.
                mstore(
                    TokenTransferGenericFailure_error_sig_ptr,
                    TokenTransferGenericFailure_error_signature
                )
                mstore(TokenTransferGenericFailure_error_token_ptr, token)
                mstore(TokenTransferGenericFailure_error_from_ptr, from)
                mstore(TokenTransferGenericFailure_error_to_ptr, to)
                mstore(TokenTransferGenericFailure_error_id_ptr, identifier)
                mstore(TokenTransferGenericFailure_error_amount_ptr, 1)
                revert(
                    TokenTransferGenericFailure_error_sig_ptr,
                    TokenTransferGenericFailure_error_length
                )
            }
            // Restore the original free memory pointer.
            mstore(FreeMemoryPointerSlot, memPointer)
            // Restore the zero slot to zero.
            mstore(ZeroSlot, 0)
        }
    }
    /**
     * @dev Internal function to transfer ERC1155 tokens from a given
     *      originator to a given recipient. Sufficient approvals must be set on
     *      the contract performing the transfer and contract recipients must
     *      implement the ERC1155TokenReceiver interface to indicate that they
     *      are willing to accept the transfer.
     *
     * @param token      The ERC1155 token to transfer.
     * @param from       The originator of the transfer.
     * @param to         The recipient of the transfer.
     * @param identifier The id to transfer.
     * @param amount     The amount to transfer.
     */
    function _performERC1155Transfer(
        address token,
        address from,
        address to,
        uint256 identifier,
        uint256 amount
    ) internal {
        // Utilize assembly to perform an optimized ERC1155 token transfer.
        assembly {
            // If the token has no code, revert.
            if iszero(extcodesize(token)) {
                mstore(NoContract_error_sig_ptr, NoContract_error_signature)
                mstore(NoContract_error_token_ptr, token)
                revert(NoContract_error_sig_ptr, NoContract_error_length)
            }
            // The following memory slots will be used when populating call data
            // for the transfer; read the values and restore them later.
            let memPointer := mload(FreeMemoryPointerSlot)
            let slot0x80 := mload(Slot0x80)
            let slot0xA0 := mload(Slot0xA0)
            let slot0xC0 := mload(Slot0xC0)
            // Write call data into memory, beginning with function selector.
            mstore(
                ERC1155_safeTransferFrom_sig_ptr,
                ERC1155_safeTransferFrom_signature
            )
            mstore(ERC1155_safeTransferFrom_from_ptr, from)
            mstore(ERC1155_safeTransferFrom_to_ptr, to)
            mstore(ERC1155_safeTransferFrom_id_ptr, identifier)
            mstore(ERC1155_safeTransferFrom_amount_ptr, amount)
            mstore(
                ERC1155_safeTransferFrom_data_offset_ptr,
                ERC1155_safeTransferFrom_data_length_offset
            )
            mstore(ERC1155_safeTransferFrom_data_length_ptr, 0)
            // Perform the call, ignoring return data.
            let success := call(
                gas(),
                token,
                0,
                ERC1155_safeTransferFrom_sig_ptr,
                ERC1155_safeTransferFrom_length,
                0,
                0
            )
            // If the transfer reverted:
            if iszero(success) {
                // If it returned a message, bubble it up as long as sufficient
                // gas remains to do so:
                if returndatasize() {
                    // Ensure that sufficient gas is available to copy
                    // returndata while expanding memory where necessary. Start
                    // by computing word size of returndata & allocated memory.
                    // Round up to the nearest full word.
                    let returnDataWords := div(
                        add(returndatasize(), AlmostOneWord),
                        OneWord
                    )
                    // Note: use the free memory pointer in place of msize() to
                    // work around a Yul warning that prevents accessing msize
                    // directly when the IR pipeline is activated.
                    let msizeWords := div(memPointer, OneWord)
                    // Next, compute the cost of the returndatacopy.
                    let cost := mul(CostPerWord, returnDataWords)
                    // Then, compute cost of new memory allocation.
                    if gt(returnDataWords, msizeWords) {
                        cost := add(
                            cost,
                            add(
                                mul(
                                    sub(returnDataWords, msizeWords),
                                    CostPerWord
                                ),
                                div(
                                    sub(
                                        mul(returnDataWords, returnDataWords),
                                        mul(msizeWords, msizeWords)
                                    ),
                                    MemoryExpansionCoefficient
                                )
                            )
                        )
                    }
                    // Finally, add a small constant and compare to gas
                    // remaining; bubble up the revert data if enough gas is
                    // still available.
                    if lt(add(cost, ExtraGasBuffer), gas()) {
                        // Copy returndata to memory; overwrite existing memory.
                        returndatacopy(0, 0, returndatasize())
                        // Revert, giving memory region with copied returndata.
                        revert(0, returndatasize())
                    }
                }
                // Otherwise revert with a generic error message.
                mstore(
                    TokenTransferGenericFailure_error_sig_ptr,
                    TokenTransferGenericFailure_error_signature
                )
                mstore(TokenTransferGenericFailure_error_token_ptr, token)
                mstore(TokenTransferGenericFailure_error_from_ptr, from)
                mstore(TokenTransferGenericFailure_error_to_ptr, to)
                mstore(TokenTransferGenericFailure_error_id_ptr, identifier)
                mstore(TokenTransferGenericFailure_error_amount_ptr, amount)
                revert(
                    TokenTransferGenericFailure_error_sig_ptr,
                    TokenTransferGenericFailure_error_length
                )
            }
            mstore(Slot0x80, slot0x80) // Restore slot 0x80.
            mstore(Slot0xA0, slot0xA0) // Restore slot 0xA0.
            mstore(Slot0xC0, slot0xC0) // Restore slot 0xC0.
            // Restore the original free memory pointer.
            mstore(FreeMemoryPointerSlot, memPointer)
            // Restore the zero slot to zero.
            mstore(ZeroSlot, 0)
        }
    }
    /**
     * @dev Internal function to transfer ERC1155 tokens from a given
     *      originator to a given recipient. Sufficient approvals must be set on
     *      the contract performing the transfer and contract recipients must
     *      implement the ERC1155TokenReceiver interface to indicate that they
     *      are willing to accept the transfer. NOTE: this function is not
     *      memory-safe; it will overwrite existing memory, restore the free
     *      memory pointer to the default value, and overwrite the zero slot.
     *      This function should only be called once memory is no longer
     *      required and when uninitialized arrays are not utilized, and memory
     *      should be considered fully corrupted (aside from the existence of a
     *      default-value free memory pointer) after calling this function.
     *
     * @param batchTransfers The group of 1155 batch transfers to perform.
     */
    function _performERC1155BatchTransfers(
        ConduitBatch1155Transfer[] calldata batchTransfers
    ) internal {
        // Utilize assembly to perform optimized batch 1155 transfers.
        assembly {
            let len := batchTransfers.length
            // Pointer to first head in the array, which is offset to the struct
            // at each index. This gets incremented after each loop to avoid
            // multiplying by 32 to get the offset for each element.
            let nextElementHeadPtr := batchTransfers.offset
            // Pointer to beginning of the head of the array. This is the
            // reference position each offset references. It's held static to
            // let each loop calculate the data position for an element.
            let arrayHeadPtr := nextElementHeadPtr
            // Write the function selector, which will be reused for each call:
            // safeBatchTransferFrom(address,address,uint256[],uint256[],bytes)
            mstore(
                ConduitBatch1155Transfer_from_offset,
                ERC1155_safeBatchTransferFrom_signature
            )
            // Iterate over each batch transfer.
            for {
                let i := 0
            } lt(i, len) {
                i := add(i, 1)
            } {
                // Read the offset to the beginning of the element and add
                // it to pointer to the beginning of the array head to get
                // the absolute position of the element in calldata.
                let elementPtr := add(
                    arrayHeadPtr,
                    calldataload(nextElementHeadPtr)
                )
                // Retrieve the token from calldata.
                let token := calldataload(elementPtr)
                // If the token has no code, revert.
                if iszero(extcodesize(token)) {
                    mstore(NoContract_error_sig_ptr, NoContract_error_signature)
                    mstore(NoContract_error_token_ptr, token)
                    revert(NoContract_error_sig_ptr, NoContract_error_length)
                }
                // Get the total number of supplied ids.
                let idsLength := calldataload(
                    add(elementPtr, ConduitBatch1155Transfer_ids_length_offset)
                )
                // Determine the expected offset for the amounts array.
                let expectedAmountsOffset := add(
                    ConduitBatch1155Transfer_amounts_length_baseOffset,
                    mul(idsLength, OneWord)
                )
                // Validate struct encoding.
                let invalidEncoding := iszero(
                    and(
                        // ids.length == amounts.length
                        eq(
                            idsLength,
                            calldataload(add(elementPtr, expectedAmountsOffset))
                        ),
                        and(
                            // ids_offset == 0xa0
                            eq(
                                calldataload(
                                    add(
                                        elementPtr,
                                        ConduitBatch1155Transfer_ids_head_offset
                                    )
                                ),
                                ConduitBatch1155Transfer_ids_length_offset
                            ),
                            // amounts_offset == 0xc0 + ids.length*32
                            eq(
                                calldataload(
                                    add(
                                        elementPtr,
                                        ConduitBatchTransfer_amounts_head_offset
                                    )
                                ),
                                expectedAmountsOffset
                            )
                        )
                    )
                )
                // Revert with an error if the encoding is not valid.
                if invalidEncoding {
                    mstore(
                        Invalid1155BatchTransferEncoding_ptr,
                        Invalid1155BatchTransferEncoding_selector
                    )
                    revert(
                        Invalid1155BatchTransferEncoding_ptr,
                        Invalid1155BatchTransferEncoding_length
                    )
                }
                // Update the offset position for the next loop
                nextElementHeadPtr := add(nextElementHeadPtr, OneWord)
                // Copy the first section of calldata (before dynamic values).
                calldatacopy(
                    BatchTransfer1155Params_ptr,
                    add(elementPtr, ConduitBatch1155Transfer_from_offset),
                    ConduitBatch1155Transfer_usable_head_size
                )
                // Determine size of calldata required for ids and amounts. Note
                // that the size includes both lengths as well as the data.
                let idsAndAmountsSize := add(TwoWords, mul(idsLength, TwoWords))
                // Update the offset for the data array in memory.
                mstore(
                    BatchTransfer1155Params_data_head_ptr,
                    add(
                        BatchTransfer1155Params_ids_length_offset,
                        idsAndAmountsSize
                    )
                )
                // Set the length of the data array in memory to zero.
                mstore(
                    add(
                        BatchTransfer1155Params_data_length_basePtr,
                        idsAndAmountsSize
                    ),
                    0
                )
                // Determine the total calldata size for the call to transfer.
                let transferDataSize := add(
                    BatchTransfer1155Params_calldata_baseSize,
                    idsAndAmountsSize
                )
                // Copy second section of calldata (including dynamic values).
                calldatacopy(
                    BatchTransfer1155Params_ids_length_ptr,
                    add(elementPtr, ConduitBatch1155Transfer_ids_length_offset),
                    idsAndAmountsSize
                )
                // Perform the call to transfer 1155 tokens.
                let success := call(
                    gas(),
                    token,
                    0,
                    ConduitBatch1155Transfer_from_offset, // Data portion start.
                    transferDataSize, // Location of the length of callData.
                    0,
                    0
                )
                // If the transfer reverted:
                if iszero(success) {
                    // If it returned a message, bubble it up as long as
                    // sufficient gas remains to do so:
                    if returndatasize() {
                        // Ensure that sufficient gas is available to copy
                        // returndata while expanding memory where necessary.
                        // Start by computing word size of returndata and
                        // allocated memory. Round up to the nearest full word.
                        let returnDataWords := div(
                            add(returndatasize(), AlmostOneWord),
                            OneWord
                        )
                        // Note: use transferDataSize in place of msize() to
                        // work around a Yul warning that prevents accessing
                        // msize directly when the IR pipeline is activated.
                        // The free memory pointer is not used here because
                        // this function does almost all memory management
                        // manually and does not update it, and transferDataSize
                        // should be the largest memory value used (unless a
                        // previous batch was larger).
                        let msizeWords := div(transferDataSize, OneWord)
                        // Next, compute the cost of the returndatacopy.
                        let cost := mul(CostPerWord, returnDataWords)
                        // Then, compute cost of new memory allocation.
                        if gt(returnDataWords, msizeWords) {
                            cost := add(
                                cost,
                                add(
                                    mul(
                                        sub(returnDataWords, msizeWords),
                                        CostPerWord
                                    ),
                                    div(
                                        sub(
                                            mul(
                                                returnDataWords,
                                                returnDataWords
                                            ),
                                            mul(msizeWords, msizeWords)
                                        ),
                                        MemoryExpansionCoefficient
                                    )
                                )
                            )
                        }
                        // Finally, add a small constant and compare to gas
                        // remaining; bubble up the revert data if enough gas is
                        // still available.
                        if lt(add(cost, ExtraGasBuffer), gas()) {
                            // Copy returndata to memory; overwrite existing.
                            returndatacopy(0, 0, returndatasize())
                            // Revert with memory region containing returndata.
                            revert(0, returndatasize())
                        }
                    }
                    // Set the error signature.
                    mstore(
                        0,
                        ERC1155BatchTransferGenericFailure_error_signature
                    )
                    // Write the token.
                    mstore(ERC1155BatchTransferGenericFailure_token_ptr, token)
                    // Increase the offset to ids by 32.
                    mstore(
                        BatchTransfer1155Params_ids_head_ptr,
                        ERC1155BatchTransferGenericFailure_ids_offset
                    )
                    // Increase the offset to amounts by 32.
                    mstore(
                        BatchTransfer1155Params_amounts_head_ptr,
                        add(
                            OneWord,
                            mload(BatchTransfer1155Params_amounts_head_ptr)
                        )
                    )
                    // Return modified region. The total size stays the same as
                    // `token` uses the same number of bytes as `data.length`.
                    revert(0, transferDataSize)
                }
            }
            // Reset the free memory pointer to the default value; memory must
            // be assumed to be dirtied and not reused from this point forward.
            // Also note that the zero slot is not reset to zero, meaning empty
            // arrays cannot be safely created or utilized until it is restored.
            mstore(FreeMemoryPointerSlot, DefaultFreeMemoryPointer)
        }
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
// error ChannelClosed(address channel)
uint256 constant ChannelClosed_error_signature = (
    0x93daadf200000000000000000000000000000000000000000000000000000000
);
uint256 constant ChannelClosed_error_ptr = 0x00;
uint256 constant ChannelClosed_channel_ptr = 0x4;
uint256 constant ChannelClosed_error_length = 0x24;
// For the mapping:
// mapping(address => bool) channels
// The position in storage for a particular account is:
// keccak256(abi.encode(account, channels.slot))
uint256 constant ChannelKey_channel_ptr = 0x00;
uint256 constant ChannelKey_slot_ptr = 0x20;
uint256 constant ChannelKey_length = 0x40;
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
/*
 * -------------------------- Disambiguation & Other Notes ---------------------
 *    - The term "head" is used as it is in the documentation for ABI encoding,
 *      but only in reference to dynamic types, i.e. it always refers to the
 *      offset or pointer to the body of a dynamic type. In calldata, the head
 *      is always an offset (relative to the parent object), while in memory,
 *      the head is always the pointer to the body. More information found here:
 *      https://docs.soliditylang.org/en/v0.8.14/abi-spec.html#argument-encoding
 *        - Note that the length of an array is separate from and precedes the
 *          head of the array.
 *
 *    - The term "body" is used in place of the term "head" used in the ABI
 *      documentation. It refers to the start of the data for a dynamic type,
 *      e.g. the first word of a struct or the first word of the first element
 *      in an array.
 *
 *    - The term "pointer" is used to describe the absolute position of a value
 *      and never an offset relative to another value.
 *        - The suffix "_ptr" refers to a memory pointer.
 *        - The suffix "_cdPtr" refers to a calldata pointer.
 *
 *    - The term "offset" is used to describe the position of a value relative
 *      to some parent value. For example, OrderParameters_conduit_offset is the
 *      offset to the "conduit" value in the OrderParameters struct relative to
 *      the start of the body.
 *        - Note: Offsets are used to derive pointers.
 *
 *    - Some structs have pointers defined for all of their fields in this file.
 *      Lines which are commented out are fields that are not used in the
 *      codebase but have been left in for readability.
 */
uint256 constant AlmostOneWord = 0x1f;
uint256 constant OneWord = 0x20;
uint256 constant TwoWords = 0x40;
uint256 constant ThreeWords = 0x60;
uint256 constant FreeMemoryPointerSlot = 0x40;
uint256 constant ZeroSlot = 0x60;
uint256 constant DefaultFreeMemoryPointer = 0x80;
uint256 constant Slot0x80 = 0x80;
uint256 constant Slot0xA0 = 0xa0;
uint256 constant Slot0xC0 = 0xc0;
// abi.encodeWithSignature("transferFrom(address,address,uint256)")
uint256 constant ERC20_transferFrom_signature = (
    0x23b872dd00000000000000000000000000000000000000000000000000000000
);
uint256 constant ERC20_transferFrom_sig_ptr = 0x0;
uint256 constant ERC20_transferFrom_from_ptr = 0x04;
uint256 constant ERC20_transferFrom_to_ptr = 0x24;
uint256 constant ERC20_transferFrom_amount_ptr = 0x44;
uint256 constant ERC20_transferFrom_length = 0x64; // 4 + 32 * 3 == 100
// abi.encodeWithSignature(
//     "safeTransferFrom(address,address,uint256,uint256,bytes)"
// )
uint256 constant ERC1155_safeTransferFrom_signature = (
    0xf242432a00000000000000000000000000000000000000000000000000000000
);
uint256 constant ERC1155_safeTransferFrom_sig_ptr = 0x0;
uint256 constant ERC1155_safeTransferFrom_from_ptr = 0x04;
uint256 constant ERC1155_safeTransferFrom_to_ptr = 0x24;
uint256 constant ERC1155_safeTransferFrom_id_ptr = 0x44;
uint256 constant ERC1155_safeTransferFrom_amount_ptr = 0x64;
uint256 constant ERC1155_safeTransferFrom_data_offset_ptr = 0x84;
uint256 constant ERC1155_safeTransferFrom_data_length_ptr = 0xa4;
uint256 constant ERC1155_safeTransferFrom_length = 0xc4; // 4 + 32 * 6 == 196
uint256 constant ERC1155_safeTransferFrom_data_length_offset = 0xa0;
// abi.encodeWithSignature(
//     "safeBatchTransferFrom(address,address,uint256[],uint256[],bytes)"
// )
uint256 constant ERC1155_safeBatchTransferFrom_signature = (
    0x2eb2c2d600000000000000000000000000000000000000000000000000000000
);
bytes4 constant ERC1155_safeBatchTransferFrom_selector = bytes4(
    bytes32(ERC1155_safeBatchTransferFrom_signature)
);
uint256 constant ERC721_transferFrom_signature = ERC20_transferFrom_signature;
uint256 constant ERC721_transferFrom_sig_ptr = 0x0;
uint256 constant ERC721_transferFrom_from_ptr = 0x04;
uint256 constant ERC721_transferFrom_to_ptr = 0x24;
uint256 constant ERC721_transferFrom_id_ptr = 0x44;
uint256 constant ERC721_transferFrom_length = 0x64; // 4 + 32 * 3 == 100
// abi.encodeWithSignature("NoContract(address)")
uint256 constant NoContract_error_signature = (
    0x5f15d67200000000000000000000000000000000000000000000000000000000
);
uint256 constant NoContract_error_sig_ptr = 0x0;
uint256 constant NoContract_error_token_ptr = 0x4;
uint256 constant NoContract_error_length = 0x24; // 4 + 32 == 36
// abi.encodeWithSignature(
//     "TokenTransferGenericFailure(address,address,address,uint256,uint256)"
// )
uint256 constant TokenTransferGenericFailure_error_signature = (
    0xf486bc8700000000000000000000000000000000000000000000000000000000
);
uint256 constant TokenTransferGenericFailure_error_sig_ptr = 0x0;
uint256 constant TokenTransferGenericFailure_error_token_ptr = 0x4;
uint256 constant TokenTransferGenericFailure_error_from_ptr = 0x24;
uint256 constant TokenTransferGenericFailure_error_to_ptr = 0x44;
uint256 constant TokenTransferGenericFailure_error_id_ptr = 0x64;
uint256 constant TokenTransferGenericFailure_error_amount_ptr = 0x84;
// 4 + 32 * 5 == 164
uint256 constant TokenTransferGenericFailure_error_length = 0xa4;
// abi.encodeWithSignature(
//     "BadReturnValueFromERC20OnTransfer(address,address,address,uint256)"
// )
uint256 constant BadReturnValueFromERC20OnTransfer_error_signature = (
    0x9889192300000000000000000000000000000000000000000000000000000000
);
uint256 constant BadReturnValueFromERC20OnTransfer_error_sig_ptr = 0x0;
uint256 constant BadReturnValueFromERC20OnTransfer_error_token_ptr = 0x4;
uint256 constant BadReturnValueFromERC20OnTransfer_error_from_ptr = 0x24;
uint256 constant BadReturnValueFromERC20OnTransfer_error_to_ptr = 0x44;
uint256 constant BadReturnValueFromERC20OnTransfer_error_amount_ptr = 0x64;
// 4 + 32 * 4 == 132
uint256 constant BadReturnValueFromERC20OnTransfer_error_length = 0x84;
uint256 constant ExtraGasBuffer = 0x20;
uint256 constant CostPerWord = 3;
uint256 constant MemoryExpansionCoefficient = 0x200;
// Values are offset by 32 bytes in order to write the token to the beginning
// in the event of a revert
uint256 constant BatchTransfer1155Params_ptr = 0x24;
uint256 constant BatchTransfer1155Params_ids_head_ptr = 0x64;
uint256 constant BatchTransfer1155Params_amounts_head_ptr = 0x84;
uint256 constant BatchTransfer1155Params_data_head_ptr = 0xa4;
uint256 constant BatchTransfer1155Params_data_length_basePtr = 0xc4;
uint256 constant BatchTransfer1155Params_calldata_baseSize = 0xc4;
uint256 constant BatchTransfer1155Params_ids_length_ptr = 0xc4;
uint256 constant BatchTransfer1155Params_ids_length_offset = 0xa0;
uint256 constant BatchTransfer1155Params_amounts_length_baseOffset = 0xc0;
uint256 constant BatchTransfer1155Params_data_length_baseOffset = 0xe0;
uint256 constant ConduitBatch1155Transfer_usable_head_size = 0x80;
uint256 constant ConduitBatch1155Transfer_from_offset = 0x20;
uint256 constant ConduitBatch1155Transfer_ids_head_offset = 0x60;
uint256 constant ConduitBatch1155Transfer_amounts_head_offset = 0x80;
uint256 constant ConduitBatch1155Transfer_ids_length_offset = 0xa0;
uint256 constant ConduitBatch1155Transfer_amounts_length_baseOffset = 0xc0;
uint256 constant ConduitBatch1155Transfer_calldata_baseSize = 0xc0;
// Note: abbreviated version of above constant to adhere to line length limit.
uint256 constant ConduitBatchTransfer_amounts_head_offset = 0x80;
uint256 constant Invalid1155BatchTransferEncoding_ptr = 0x00;
uint256 constant Invalid1155BatchTransferEncoding_length = 0x04;
uint256 constant Invalid1155BatchTransferEncoding_selector = (
    0xeba2084c00000000000000000000000000000000000000000000000000000000
);
uint256 constant ERC1155BatchTransferGenericFailure_error_signature = (
    0xafc445e200000000000000000000000000000000000000000000000000000000
);
uint256 constant ERC1155BatchTransferGenericFailure_token_ptr = 0x04;
uint256 constant ERC1155BatchTransferGenericFailure_ids_offset = 0xc0;
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
/**
 * @title TokenTransferrerErrors
 */
interface TokenTransferrerErrors {
    /**
     * @dev Revert with an error when an ERC721 transfer with amount other than
     *      one is attempted.
     */
    error InvalidERC721TransferAmount();
    /**
     * @dev Revert with an error when attempting to fulfill an order where an
     *      item has an amount of zero.
     */
    error MissingItemAmount();
    /**
     * @dev Revert with an error when attempting to fulfill an order where an
     *      item has unused parameters. This includes both the token and the
     *      identifier parameters for native transfers as well as the identifier
     *      parameter for ERC20 transfers. Note that the conduit does not
     *      perform this check, leaving it up to the calling channel to enforce
     *      when desired.
     */
    error UnusedItemParameters();
    /**
     * @dev Revert with an error when an ERC20, ERC721, or ERC1155 token
     *      transfer reverts.
     *
     * @param token      The token for which the transfer was attempted.
     * @param from       The source of the attempted transfer.
     * @param to         The recipient of the attempted transfer.
     * @param identifier The identifier for the attempted transfer.
     * @param amount     The amount for the attempted transfer.
     */
    error TokenTransferGenericFailure(
        address token,
        address from,
        address to,
        uint256 identifier,
        uint256 amount
    );
    /**
     * @dev Revert with an error when a batch ERC1155 token transfer reverts.
     *
     * @param token       The token for which the transfer was attempted.
     * @param from        The source of the attempted transfer.
     * @param to          The recipient of the attempted transfer.
     * @param identifiers The identifiers for the attempted transfer.
     * @param amounts     The amounts for the attempted transfer.
     */
    error ERC1155BatchTransferGenericFailure(
        address token,
        address from,
        address to,
        uint256[] identifiers,
        uint256[] amounts
    );
    /**
     * @dev Revert with an error when an ERC20 token transfer returns a falsey
     *      value.
     *
     * @param token      The token for which the ERC20 transfer was attempted.
     * @param from       The source of the attempted ERC20 transfer.
     * @param to         The recipient of the attempted ERC20 transfer.
     * @param amount     The amount for the attempted ERC20 transfer.
     */
    error BadReturnValueFromERC20OnTransfer(
        address token,
        address from,
        address to,
        uint256 amount
    );
    /**
     * @dev Revert with an error when an account being called as an assumed
     *      contract does not have code and returns no data.
     *
     * @param account The account that should contain code.
     */
    error NoContract(address account);
    /**
     * @dev Revert with an error when attempting to execute an 1155 batch
     *      transfer using calldata not produced by default ABI encoding or with
     *      different lengths for ids and amounts arrays.
     */
    error Invalid1155BatchTransferEncoding();
}

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

// SPDX-License-Identifier: MIT

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/token/ERC721/IERC721.sol



pragma solidity ^0.8.0;


/**
 * @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`, 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 be 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: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * 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 Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @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 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);

    /**
      * @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;
}

// File: @openzeppelin/contracts/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 `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(address operator, address from, uint256 tokenId, bytes calldata data) external returns (bytes4);
}

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



pragma solidity ^0.8.0;


/**
 * @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/utils/Address.sol



pragma solidity ^0.8.0;

/**
 * @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
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 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://diligence.consensys.net/posts/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/v0.5.11/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");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (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 functionCall(target, data, "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");
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return _verifyCallResult(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) {
        require(isContract(target), "Address: static call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(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) {
        require(isContract(target), "Address: delegate call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
        if (success) {
            return returndata;
        } else {
            // 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

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: @openzeppelin/contracts/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) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

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



pragma solidity ^0.8.0;

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

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

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

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

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

}

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



pragma solidity ^0.8.0;


/**
 * @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/token/ERC721/ERC721.sol



pragma solidity ^0.8.0;








/**
 * @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: balance query for the zero address");
        return _balances[owner];
    }

    /**
     * @dev See {IERC721-ownerOf}.
     */
    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        address owner = _owners[tokenId];
        require(owner != address(0), "ERC721: owner query for nonexistent token");
        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) {
        require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");

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

    /**
     * @dev Base URI for computing {tokenURI}. Empty by default, can be overriden
     * 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 owner nor approved for all"
        );

        _approve(to, tokenId);
    }

    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        require(_exists(tokenId), "ERC721: approved query for nonexistent token");

        return _tokenApprovals[tokenId];
    }

    /**
     * @dev See {IERC721-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        require(operator != _msgSender(), "ERC721: approve to caller");

        _operatorApprovals[_msgSender()][operator] = approved;
        emit ApprovalForAll(_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: transfer caller is not owner nor 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: transfer caller is not owner nor 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 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 _owners[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) {
        require(_exists(tokenId), "ERC721: operator query for nonexistent token");
        address owner = ERC721.ownerOf(tokenId);
        return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, 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);

        _balances[to] += 1;
        _owners[tokenId] = to;

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

    /**
     * @dev Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId) internal virtual {
        address owner = ERC721.ownerOf(tokenId);

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

        // Clear approvals
        _approve(address(0), tokenId);

        _balances[owner] -= 1;
        delete _owners[tokenId];

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

    /**
     * @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 of token that is not own");
        require(to != address(0), "ERC721: transfer to the zero address");

        _beforeTokenTransfer(from, to, tokenId);

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

        _balances[from] -= 1;
        _balances[to] += 1;
        _owners[tokenId] = to;

        emit Transfer(from, to, tokenId);
    }

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

    /**
     * @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(to).onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert("ERC721: transfer to non ERC721Receiver implementer");
                } else {
                    // solhint-disable-next-line no-inline-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.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, ``from``'s `tokenId` will be burned.
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 tokenId) internal virtual { }
}

// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol



pragma solidity ^0.8.0;


/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Enumerable is IERC721 {

    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns a token ID owned by `owner` at a given `index` of its token list.
     * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId);

    /**
     * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
     * Use along with {totalSupply} to enumerate all tokens.
     */
    function tokenByIndex(uint256 index) external view returns (uint256);
}

// File: @openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol



pragma solidity ^0.8.0;



/**
 * @dev This implements an optional extension of {ERC721} defined in the EIP that adds
 * enumerability of all the token ids in the contract as well as all token ids owned by each
 * account.
 */
abstract contract ERC721Enumerable is ERC721, IERC721Enumerable {
    // Mapping from owner to list of owned token IDs
    mapping(address => mapping(uint256 => uint256)) private _ownedTokens;

    // Mapping from token ID to index of the owner tokens list
    mapping(uint256 => uint256) private _ownedTokensIndex;

    // Array with all token ids, used for enumeration
    uint256[] private _allTokens;

    // Mapping from token id to position in the allTokens array
    mapping(uint256 => uint256) private _allTokensIndex;

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC721) returns (bool) {
        return interfaceId == type(IERC721Enumerable).interfaceId
            || super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721.balanceOf(owner), "ERC721Enumerable: owner index out of bounds");
        return _ownedTokens[owner][index];
    }

    /**
     * @dev See {IERC721Enumerable-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _allTokens.length;
    }

    /**
     * @dev See {IERC721Enumerable-tokenByIndex}.
     */
    function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721Enumerable.totalSupply(), "ERC721Enumerable: global index out of bounds");
        return _allTokens[index];
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, ``from``'s `tokenId` will be burned.
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 tokenId) internal virtual override {
        super._beforeTokenTransfer(from, to, tokenId);

        if (from == address(0)) {
            _addTokenToAllTokensEnumeration(tokenId);
        } else if (from != to) {
            _removeTokenFromOwnerEnumeration(from, tokenId);
        }
        if (to == address(0)) {
            _removeTokenFromAllTokensEnumeration(tokenId);
        } else if (to != from) {
            _addTokenToOwnerEnumeration(to, tokenId);
        }
    }

    /**
     * @dev Private function to add a token to this extension's ownership-tracking data structures.
     * @param to address representing the new owner of the given token ID
     * @param tokenId uint256 ID of the token to be added to the tokens list of the given address
     */
    function _addTokenToOwnerEnumeration(address to, uint256 tokenId) private {
        uint256 length = ERC721.balanceOf(to);
        _ownedTokens[to][length] = tokenId;
        _ownedTokensIndex[tokenId] = length;
    }

    /**
     * @dev Private function to add a token to this extension's token tracking data structures.
     * @param tokenId uint256 ID of the token to be added to the tokens list
     */
    function _addTokenToAllTokensEnumeration(uint256 tokenId) private {
        _allTokensIndex[tokenId] = _allTokens.length;
        _allTokens.push(tokenId);
    }

    /**
     * @dev Private function to remove a token from this extension's ownership-tracking data structures. Note that
     * while the token is not assigned a new owner, the `_ownedTokensIndex` mapping is _not_ updated: this allows for
     * gas optimizations e.g. when performing a transfer operation (avoiding double writes).
     * This has O(1) time complexity, but alters the order of the _ownedTokens array.
     * @param from address representing the previous owner of the given token ID
     * @param tokenId uint256 ID of the token to be removed from the tokens list of the given address
     */
    function _removeTokenFromOwnerEnumeration(address from, uint256 tokenId) private {
        // To prevent a gap in from's tokens array, we store the last token in the index of the token to delete, and
        // then delete the last slot (swap and pop).

        uint256 lastTokenIndex = ERC721.balanceOf(from) - 1;
        uint256 tokenIndex = _ownedTokensIndex[tokenId];

        // When the token to delete is the last token, the swap operation is unnecessary
        if (tokenIndex != lastTokenIndex) {
            uint256 lastTokenId = _ownedTokens[from][lastTokenIndex];

            _ownedTokens[from][tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
            _ownedTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index
        }

        // This also deletes the contents at the last position of the array
        delete _ownedTokensIndex[tokenId];
        delete _ownedTokens[from][lastTokenIndex];
    }

    /**
     * @dev Private function to remove a token from this extension's token tracking data structures.
     * This has O(1) time complexity, but alters the order of the _allTokens array.
     * @param tokenId uint256 ID of the token to be removed from the tokens list
     */
    function _removeTokenFromAllTokensEnumeration(uint256 tokenId) private {
        // To prevent a gap in the tokens array, we store the last token in the index of the token to delete, and
        // then delete the last slot (swap and pop).

        uint256 lastTokenIndex = _allTokens.length - 1;
        uint256 tokenIndex = _allTokensIndex[tokenId];

        // When the token to delete is the last token, the swap operation is unnecessary. However, since this occurs so
        // rarely (when the last minted token is burnt) that we still do the swap here to avoid the gas cost of adding
        // an 'if' statement (like in _removeTokenFromOwnerEnumeration)
        uint256 lastTokenId = _allTokens[lastTokenIndex];

        _allTokens[tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
        _allTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index

        // This also deletes the contents at the last position of the array
        delete _allTokensIndex[tokenId];
        _allTokens.pop();
    }
}

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



pragma solidity ^0.8.0;

/**
 * @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 () {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

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

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

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

// File: contracts/BoredApeKennelClub.sol


pragma solidity ^0.8.0;



abstract contract BAYC {
  function ownerOf(uint256 tokenId) public virtual view returns (address);
  function tokenOfOwnerByIndex(address owner, uint256 index) public virtual view returns (uint256);
  function balanceOf(address owner) external virtual view returns (uint256 balance);
}

contract BoredApeKennelClub is ERC721Enumerable, Ownable {  
  BAYC private bayc;

  uint constant public MAX_DOG_ADOPTION = 50;
  string public BakcProvenance;
  bool public saleIsActive = false;
  uint256 public collectionStartingIndex;
  uint256 public collectionStartingIndexBlock;
  uint256 public maxDogs;
  uint256 public setBlockTimestamp;
  uint256 public revealTimestamp;
  string private baseURI;

  constructor(
    string memory name,
    string memory symbol,
    uint256 maxNftSupply,
    uint256 saleStart,
    address dependentContractAddress
  ) ERC721(name, symbol) {
    maxDogs = maxNftSupply;
    revealTimestamp = saleStart + (86400 * 7);
    setBlockTimestamp = saleStart + (86400 * 6);
    bayc = BAYC(dependentContractAddress);
  }

  function setRevealTimestamp(uint256 revealTimeStamp) public onlyOwner {
    revealTimestamp = revealTimeStamp;
  }

  function setStartingBlockTimestamp(uint256 startingBlockTimestamp) public onlyOwner {
    setBlockTimestamp = startingBlockTimestamp;
  }

  function setProvenanceHash(string memory provenanceHash) public onlyOwner {
    BakcProvenance = provenanceHash;
  }

  function isMinted(uint256 tokenId) external view returns (bool) {
    require(tokenId < maxDogs, "tokenId outside collection bounds");

    return _exists(tokenId);
  }

  function _baseURI() internal view override returns (string memory) {
    return baseURI;
  }
  
  function setBaseURI(string memory uri) public onlyOwner {
    baseURI = uri;
  }

  function flipSaleState() public onlyOwner {
    saleIsActive = !saleIsActive;
  }

  function trySetStartingIndexBlock() private {
    if (
      collectionStartingIndexBlock == 0 &&
      (totalSupply() == maxDogs || block.timestamp >= setBlockTimestamp)
    ) {
      collectionStartingIndexBlock = block.number;
    }
  }

  /**
    * DM Gordy in Discord that you've got a cure for his bAby MoUtH.
    */
  function adoptDog(uint256 baycTokenId) public {
    require(saleIsActive, "Sale must be active to mint a Dog");
    require(totalSupply() < maxDogs, "Purchase would exceed max supply of Dogs");
    require(baycTokenId < maxDogs, "Requested tokenId exceeds upper bound");
    require(bayc.ownerOf(baycTokenId) == msg.sender, "Must own the Bored Ape for requested tokenId to mint a Dog");
    
    _safeMint(msg.sender, baycTokenId);
    trySetStartingIndexBlock();
  }

  /**
    * DM Garga in Discord, ask him if he's done his pushups
    */
  function adoptNDogs(uint256 startingIndex, uint256 numDogs) public {
    require(saleIsActive, "Sale must be active to mint a Dog");
    require(numDogs > 0, "Must adopt at least one dog");
    require(numDogs <= MAX_DOG_ADOPTION, "Cannot adopt more than fifty dogs at once");
    uint balance = bayc.balanceOf(msg.sender);
    require(balance > 0, "Must hold at least one Ape to mint a Dog");
    require(balance >= startingIndex + numDogs, "Must hold at least as many Apes as the number of Dogs you intend to mint");

    for(uint i = 0; i < balance && i < numDogs && i < MAX_DOG_ADOPTION; i++) {
      require(totalSupply() < maxDogs, "Cannot exceed max supply of Dogs.");
      uint tokenId = bayc.tokenOfOwnerByIndex(msg.sender, i + startingIndex);
      if (!_exists(tokenId)) {
        _safeMint(msg.sender, tokenId);
      }
    }

    trySetStartingIndexBlock();
  }

  /**
    * Set the starting index for the collection
    */
  function setStartingIndex() public {
    require(collectionStartingIndex == 0, "Starting index is already set");
    require(collectionStartingIndexBlock != 0, "Starting index block must be set");
    require(
      block.timestamp >= revealTimestamp || totalSupply() == maxDogs, 
      "Must be on or after the reveal time to set starting index"
    );

    collectionStartingIndex = uint256(blockhash(collectionStartingIndexBlock)) % maxDogs;

    // Just a sanity case in the worst case if this function is called late (EVM only stores last 256 block hashes)
    if ((block.number - collectionStartingIndexBlock) > 255) {
      collectionStartingIndex = uint256(blockhash(block.number - 1)) % maxDogs;
    }

    // Prevent default sequence
    if (collectionStartingIndex == 0) {
      collectionStartingIndex = collectionStartingIndex + 1;
    }
  }

  /**
    * Set the starting index block for the collection, essentially unblocking
    * setting starting index
    */
  function emergencySetStartingIndexBlock() public onlyOwner {
    require(collectionStartingIndexBlock == 0, "Starting index block is already set");
    require(collectionStartingIndex == 0, "Starting index is already set");

    collectionStartingIndexBlock = block.number;
  }
}