pragma solidity 0.4.26;

library SafeMath {

  /**
  * @dev Multiplies two numbers, throws on overflow.
  */
  function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
    if (a == 0) {
      return 0;
    }
    c = a * b;
    assert(c / a == b);
    return c;
  }

  /**
  * @dev Integer division of two numbers, truncating the quotient.
  */
  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    // assert(b > 0); // Solidity automatically throws when dividing by 0
    // uint256 c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold
    return a / b;
  }

  /**
  * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
  */
  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  /**
  * @dev Adds two numbers, throws on overflow.
  */
  function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
    c = a + b;
    assert(c >= a);
    return c;
  }
}

contract Ownable {
  address public owner;


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


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  constructor() public {
    owner = msg.sender;
  }

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

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) public onlyOwner {
    require(newOwner != address(0));
    emit OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

  /**
   * @dev Allows the current owner to relinquish control of the contract.
   */
  function renounceOwnership() public onlyOwner {
    emit OwnershipRenounced(owner);
    owner = address(0);
  }
}

contract ERC20Basic {
  function totalSupply() public view returns (uint256);
  function balanceOf(address who) public view returns (uint256);
  function transfer(address to, uint256 value) public returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
}

contract ERC20 is ERC20Basic {
  function allowance(address owner, address spender)
    public view returns (uint256);

  function transferFrom(address from, address to, uint256 value)
    public returns (bool);

  function approve(address spender, uint256 value) public returns (bool);
  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}

library ArrayUtils {

    /**
     * Replace bytes in an array with bytes in another array, guarded by a bitmask
     * Efficiency of this function is a bit unpredictable because of the EVM's word-specific model (arrays under 32 bytes will be slower)
     *
     * @dev Mask must be the size of the byte array. A nonzero byte means the byte array can be changed.
     * @param array The original array
     * @param desired The target array
     * @param mask The mask specifying which bits can be changed
     * @return The updated byte array (the parameter will be modified inplace)
     */
    function guardedArrayReplace(bytes memory array, bytes memory desired, bytes memory mask)
        internal
        pure
    {
        require(array.length == desired.length);
        require(array.length == mask.length);

        uint words = array.length / 0x20;
        uint index = words * 0x20;
        assert(index / 0x20 == words);
        uint i;

        for (i = 0; i < words; i++) {
            /* Conceptually: array[i] = (!mask[i] && array[i]) || (mask[i] && desired[i]), bitwise in word chunks. */
            assembly {
                let commonIndex := mul(0x20, add(1, i))
                let maskValue := mload(add(mask, commonIndex))
                mstore(add(array, commonIndex), or(and(not(maskValue), mload(add(array, commonIndex))), and(maskValue, mload(add(desired, commonIndex)))))
            }
        }

        /* Deal with the last section of the byte array. */
        if (words > 0) {
            /* This overlaps with bytes already set but is still more efficient than iterating through each of the remaining bytes individually. */
            i = words;
            assembly {
                let commonIndex := mul(0x20, add(1, i))
                let maskValue := mload(add(mask, commonIndex))
                mstore(add(array, commonIndex), or(and(not(maskValue), mload(add(array, commonIndex))), and(maskValue, mload(add(desired, commonIndex)))))
            }
        } else {
            /* If the byte array is shorter than a word, we must unfortunately do the whole thing bytewise.
               (bounds checks could still probably be optimized away in assembly, but this is a rare case) */
            for (i = index; i < array.length; i++) {
                array[i] = ((mask[i] ^ 0xff) & array[i]) | (mask[i] & desired[i]);
            }
        }
    }

    /**
     * Test if two arrays are equal
     * @param a First array
     * @param b Second array
     * @return Whether or not all bytes in the arrays are equal
     */
    function arrayEq(bytes memory a, bytes memory b)
        internal
        pure
        returns (bool)
    {
        return keccak256(a) == keccak256(b);
    }

    /**
     * Unsafe write byte array into a memory location
     *
     * @param index Memory location
     * @param source Byte array to write
     * @return End memory index
     */
    function unsafeWriteBytes(uint index, bytes source)
        internal
        pure
        returns (uint)
    {
        if (source.length > 0) {
            assembly {
                let length := mload(source)
                let end := add(source, add(0x20, length))
                let arrIndex := add(source, 0x20)
                let tempIndex := index
                for { } eq(lt(arrIndex, end), 1) {
                    arrIndex := add(arrIndex, 0x20)
                    tempIndex := add(tempIndex, 0x20)
                } {
                    mstore(tempIndex, mload(arrIndex))
                }
                index := add(index, length)
            }
        }
        return index;
    }

    /**
     * Unsafe write address into a memory location
     *
     * @param index Memory location
     * @param source Address to write
     * @return End memory index
     */
    function unsafeWriteAddress(uint index, address source)
        internal
        pure
        returns (uint)
    {
        uint conv = uint(source) << 0x60;
        assembly {
            mstore(index, conv)
            index := add(index, 0x14)
        }
        return index;
    }

    /**
     * Unsafe write address into a memory location using entire word
     *
     * @param index Memory location
     * @param source uint to write
     * @return End memory index
     */
    function unsafeWriteAddressWord(uint index, address source)
        internal
        pure
        returns (uint)
    {
        assembly {
            mstore(index, source)
            index := add(index, 0x20)
        }
        return index;
    }

    /**
     * Unsafe write uint into a memory location
     *
     * @param index Memory location
     * @param source uint to write
     * @return End memory index
     */
    function unsafeWriteUint(uint index, uint source)
        internal
        pure
        returns (uint)
    {
        assembly {
            mstore(index, source)
            index := add(index, 0x20)
        }
        return index;
    }

    /**
     * Unsafe write uint8 into a memory location
     *
     * @param index Memory location
     * @param source uint8 to write
     * @return End memory index
     */
    function unsafeWriteUint8(uint index, uint8 source)
        internal
        pure
        returns (uint)
    {
        assembly {
            mstore8(index, source)
            index := add(index, 0x1)
        }
        return index;
    }

    /**
     * Unsafe write uint8 into a memory location using entire word
     *
     * @param index Memory location
     * @param source uint to write
     * @return End memory index
     */
    function unsafeWriteUint8Word(uint index, uint8 source)
        internal
        pure
        returns (uint)
    {
        assembly {
            mstore(index, source)
            index := add(index, 0x20)
        }
        return index;
    }

    /**
     * Unsafe write bytes32 into a memory location using entire word
     *
     * @param index Memory location
     * @param source uint to write
     * @return End memory index
     */
    function unsafeWriteBytes32(uint index, bytes32 source)
        internal
        pure
        returns (uint)
    {
        assembly {
            mstore(index, source)
            index := add(index, 0x20)
        }
        return index;
    }
}

contract ReentrancyGuarded {

    bool reentrancyLock = false;

    /* Prevent a contract function from being reentrant-called. */
    modifier reentrancyGuard {
        if (reentrancyLock) {
            revert();
        }
        reentrancyLock = true;
        _;
        reentrancyLock = false;
    }

}

contract TokenRecipient {
    event ReceivedEther(address indexed sender, uint amount);
    event ReceivedTokens(address indexed from, uint256 value, address indexed token, bytes extraData);

    /**
     * @dev Receive tokens and generate a log event
     * @param from Address from which to transfer tokens
     * @param value Amount of tokens to transfer
     * @param token Address of token
     * @param extraData Additional data to log
     */
    function receiveApproval(address from, uint256 value, address token, bytes extraData) public {
        ERC20 t = ERC20(token);
        require(t.transferFrom(from, this, value));
        emit ReceivedTokens(from, value, token, extraData);
    }

    /**
     * @dev Receive Ether and generate a log event
     */
    function () payable public {
        emit ReceivedEther(msg.sender, msg.value);
    }
}

contract ExchangeCore is ReentrancyGuarded, Ownable {
    string public constant name = "Wyvern Exchange Contract";
    string public constant version = "2.3";

    // NOTE: these hashes are derived and verified in the constructor.
    bytes32 private constant _EIP_712_DOMAIN_TYPEHASH = 0x8b73c3c69bb8fe3d512ecc4cf759cc79239f7b179b0ffacaa9a75d522b39400f;
    bytes32 private constant _NAME_HASH = 0x9a2ed463836165738cfa54208ff6e7847fd08cbaac309aac057086cb0a144d13;
    bytes32 private constant _VERSION_HASH = 0xe2fd538c762ee69cab09ccd70e2438075b7004dd87577dc3937e9fcc8174bb64;
    bytes32 private constant _ORDER_TYPEHASH = 0xdba08a88a748f356e8faf8578488343eab21b1741728779c9dcfdc782bc800f8;

    bytes4 private constant _EIP_1271_MAGIC_VALUE = 0x1626ba7e;

    //    // NOTE: chainId opcode is not supported in solidiy 0.4.x; here we hardcode as 1.
    // In order to protect against orders that are replayable across forked chains,
    // either the solidity version needs to be bumped up or it needs to be retrieved
    // from another contract.
    uint256 private constant _CHAIN_ID = 1;

    // Note: the domain separator is derived and verified in the constructor. */
    bytes32 public constant DOMAIN_SEPARATOR = 0x72982d92449bfb3d338412ce4738761aff47fb975ceb17a1bc3712ec716a5a68;

    /* The token used to pay exchange fees. */
    ERC20 public exchangeToken;

    /* User registry. */
    ProxyRegistry public registry;

    /* Token transfer proxy. */
    TokenTransferProxy public tokenTransferProxy;

    /* Cancelled / finalized orders, by hash. */
    mapping(bytes32 => bool) public cancelledOrFinalized;

    /* Orders verified by on-chain approval (alternative to ECDSA signatures so that smart contracts can place orders directly). */
    /* Note that the maker's nonce at the time of approval **plus one** is stored in the mapping. */
    mapping(bytes32 => uint256) private _approvedOrdersByNonce;

    /* Track per-maker nonces that can be incremented by the maker to cancel orders in bulk. */
    // The current nonce for the maker represents the only valid nonce that can be signed by the maker
    // If a signature was signed with a nonce that's different from the one stored in nonces, it
    // will fail validation.
    mapping(address => uint256) public nonces;

    /* For split fee orders, minimum required protocol maker fee, in basis points. Paid to owner (who can change it). */
    uint public minimumMakerProtocolFee = 0;

    /* For split fee orders, minimum required protocol taker fee, in basis points. Paid to owner (who can change it). */
    uint public minimumTakerProtocolFee = 0;

    /* Recipient of protocol fees. */
    address public protocolFeeRecipient;

    /* Fee method: protocol fee or split fee. */
    enum FeeMethod { ProtocolFee, SplitFee }

    /* Inverse basis point. */
    uint public constant INVERSE_BASIS_POINT = 10000;

    /* An ECDSA signature. */
    struct Sig {
        /* v parameter */
        uint8 v;
        /* r parameter */
        bytes32 r;
        /* s parameter */
        bytes32 s;
    }

    /* An order on the exchange. */
    struct Order {
        /* Exchange address, intended as a versioning mechanism. */
        address exchange;
        /* Order maker address. */
        address maker;
        /* Order taker address, if specified. */
        address taker;
        /* Maker relayer fee of the order, unused for taker order. */
        uint makerRelayerFee;
        /* Taker relayer fee of the order, or maximum taker fee for a taker order. */
        uint takerRelayerFee;
        /* Maker protocol fee of the order, unused for taker order. */
        uint makerProtocolFee;
        /* Taker protocol fee of the order, or maximum taker fee for a taker order. */
        uint takerProtocolFee;
        /* Order fee recipient or zero address for taker order. */
        address feeRecipient;
        /* Fee method (protocol token or split fee). */
        FeeMethod feeMethod;
        /* Side (buy/sell). */
        SaleKindInterface.Side side;
        /* Kind of sale. */
        SaleKindInterface.SaleKind saleKind;
        /* Target. */
        address target;
        /* HowToCall. */
        AuthenticatedProxy.HowToCall howToCall;
        /* Calldata. */
        bytes calldata;
        /* Calldata replacement pattern, or an empty byte array for no replacement. */
        bytes replacementPattern;
        /* Static call target, zero-address for no static call. */
        address staticTarget;
        /* Static call extra data. */
        bytes staticExtradata;
        /* Token used to pay for the order, or the zero-address as a sentinel value for Ether. */
        address paymentToken;
        /* Base price of the order (in paymentTokens). */
        uint basePrice;
        /* Auction extra parameter - minimum bid increment for English auctions, starting/ending price difference. */
        uint extra;
        /* Listing timestamp. */
        uint listingTime;
        /* Expiration timestamp - 0 for no expiry. */
        uint expirationTime;
        /* Order salt, used to prevent duplicate hashes. */
        uint salt;
        /* NOTE: uint nonce is an additional component of the order but is read from storage */
    }

    event OrderApprovedPartOne    (bytes32 indexed hash, address exchange, address indexed maker, address taker, uint makerRelayerFee, uint takerRelayerFee, uint makerProtocolFee, uint takerProtocolFee, address indexed feeRecipient, FeeMethod feeMethod, SaleKindInterface.Side side, SaleKindInterface.SaleKind saleKind, address target);
    event OrderApprovedPartTwo    (bytes32 indexed hash, AuthenticatedProxy.HowToCall howToCall, bytes calldata, bytes replacementPattern, address staticTarget, bytes staticExtradata, address paymentToken, uint basePrice, uint extra, uint listingTime, uint expirationTime, uint salt, bool orderbookInclusionDesired);
    event OrderCancelled          (bytes32 indexed hash);
    event OrdersMatched           (bytes32 buyHash, bytes32 sellHash, address indexed maker, address indexed taker, uint price, bytes32 indexed metadata);
    event NonceIncremented        (address indexed maker, uint newNonce);

    constructor () public {
        require(keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)") == _EIP_712_DOMAIN_TYPEHASH);
        require(keccak256(bytes(name)) == _NAME_HASH);
        require(keccak256(bytes(version)) == _VERSION_HASH);
        require(keccak256("Order(address exchange,address maker,address taker,uint256 makerRelayerFee,uint256 takerRelayerFee,uint256 makerProtocolFee,uint256 takerProtocolFee,address feeRecipient,uint8 feeMethod,uint8 side,uint8 saleKind,address target,uint8 howToCall,bytes calldata,bytes replacementPattern,address staticTarget,bytes staticExtradata,address paymentToken,uint256 basePrice,uint256 extra,uint256 listingTime,uint256 expirationTime,uint256 salt,uint256 nonce)") == _ORDER_TYPEHASH);
        require(DOMAIN_SEPARATOR == _deriveDomainSeparator());
    }

    /**
     * @dev Derive the domain separator for EIP-712 signatures.
     * @return The domain separator.
     */
    function _deriveDomainSeparator() private view returns (bytes32) {
        return keccak256(
            abi.encode(
                _EIP_712_DOMAIN_TYPEHASH, // keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)")
                _NAME_HASH, // keccak256("Wyvern Exchange Contract")
                _VERSION_HASH, // keccak256(bytes("2.3"))
                _CHAIN_ID, // NOTE: this is fixed, need to use solidity 0.5+ or make external call to support!
                address(this)
            )
        );
    }

    /**
     * Increment a particular maker's nonce, thereby invalidating all orders that were not signed
     * with the original nonce.
     */
    function incrementNonce() external {
        uint newNonce = ++nonces[msg.sender];
        emit NonceIncremented(msg.sender, newNonce);
    }

    /**
     * @dev Change the minimum maker fee paid to the protocol (owner only)
     * @param newMinimumMakerProtocolFee New fee to set in basis points
     */
    function changeMinimumMakerProtocolFee(uint newMinimumMakerProtocolFee)
        public
        onlyOwner
    {
        minimumMakerProtocolFee = newMinimumMakerProtocolFee;
    }

    /**
     * @dev Change the minimum taker fee paid to the protocol (owner only)
     * @param newMinimumTakerProtocolFee New fee to set in basis points
     */
    function changeMinimumTakerProtocolFee(uint newMinimumTakerProtocolFee)
        public
        onlyOwner
    {
        minimumTakerProtocolFee = newMinimumTakerProtocolFee;
    }

    /**
     * @dev Change the protocol fee recipient (owner only)
     * @param newProtocolFeeRecipient New protocol fee recipient address
     */
    function changeProtocolFeeRecipient(address newProtocolFeeRecipient)
        public
        onlyOwner
    {
        protocolFeeRecipient = newProtocolFeeRecipient;
    }

    /**
     * @dev Transfer tokens
     * @param token Token to transfer
     * @param from Address to charge fees
     * @param to Address to receive fees
     * @param amount Amount of protocol tokens to charge
     */
    function transferTokens(address token, address from, address to, uint amount)
        internal
    {
        if (amount > 0) {
            require(tokenTransferProxy.transferFrom(token, from, to, amount));
        }
    }

    /**
     * @dev Charge a fee in protocol tokens
     * @param from Address to charge fees
     * @param to Address to receive fees
     * @param amount Amount of protocol tokens to charge
     */
    function chargeProtocolFee(address from, address to, uint amount)
        internal
    {
        transferTokens(exchangeToken, from, to, amount);
    }

    /**
     * @dev Execute a STATICCALL (introduced with Ethereum Metropolis, non-state-modifying external call)
     * @param target Contract to call
     * @param calldata Calldata (appended to extradata)
     * @param extradata Base data for STATICCALL (probably function selector and argument encoding)
     * @return The result of the call (success or failure)
     */
    function staticCall(address target, bytes memory calldata, bytes memory extradata)
        public
        view
        returns (bool result)
    {
        bytes memory combined = new bytes(calldata.length + extradata.length);
        uint index;
        assembly {
            index := add(combined, 0x20)
        }
        index = ArrayUtils.unsafeWriteBytes(index, extradata);
        ArrayUtils.unsafeWriteBytes(index, calldata);
        assembly {
            result := staticcall(gas, target, add(combined, 0x20), mload(combined), mload(0x40), 0)
        }
        return result;
    }

    /**
     * @dev Hash an order, returning the canonical EIP-712 order hash without the domain separator
     * @param order Order to hash
     * @param nonce maker nonce to hash
     * @return Hash of order
     */
    function hashOrder(Order memory order, uint nonce)
        internal
        pure
        returns (bytes32 hash)
    {
        /* Unfortunately abi.encodePacked doesn't work here, stack size constraints. */
        uint size = 800;
        bytes memory array = new bytes(size);
        uint index;
        assembly {
            index := add(array, 0x20)
        }
        index = ArrayUtils.unsafeWriteBytes32(index, _ORDER_TYPEHASH);
        index = ArrayUtils.unsafeWriteAddressWord(index, order.exchange);
        index = ArrayUtils.unsafeWriteAddressWord(index, order.maker);
        index = ArrayUtils.unsafeWriteAddressWord(index, order.taker);
        index = ArrayUtils.unsafeWriteUint(index, order.makerRelayerFee);
        index = ArrayUtils.unsafeWriteUint(index, order.takerRelayerFee);
        index = ArrayUtils.unsafeWriteUint(index, order.makerProtocolFee);
        index = ArrayUtils.unsafeWriteUint(index, order.takerProtocolFee);
        index = ArrayUtils.unsafeWriteAddressWord(index, order.feeRecipient);
        index = ArrayUtils.unsafeWriteUint8Word(index, uint8(order.feeMethod));
        index = ArrayUtils.unsafeWriteUint8Word(index, uint8(order.side));
        index = ArrayUtils.unsafeWriteUint8Word(index, uint8(order.saleKind));
        index = ArrayUtils.unsafeWriteAddressWord(index, order.target);
        index = ArrayUtils.unsafeWriteUint8Word(index, uint8(order.howToCall));
        index = ArrayUtils.unsafeWriteBytes32(index, keccak256(order.calldata));
        index = ArrayUtils.unsafeWriteBytes32(index, keccak256(order.replacementPattern));
        index = ArrayUtils.unsafeWriteAddressWord(index, order.staticTarget);
        index = ArrayUtils.unsafeWriteBytes32(index, keccak256(order.staticExtradata));
        index = ArrayUtils.unsafeWriteAddressWord(index, order.paymentToken);
        index = ArrayUtils.unsafeWriteUint(index, order.basePrice);
        index = ArrayUtils.unsafeWriteUint(index, order.extra);
        index = ArrayUtils.unsafeWriteUint(index, order.listingTime);
        index = ArrayUtils.unsafeWriteUint(index, order.expirationTime);
        index = ArrayUtils.unsafeWriteUint(index, order.salt);
        index = ArrayUtils.unsafeWriteUint(index, nonce);
        assembly {
            hash := keccak256(add(array, 0x20), size)
        }
        return hash;
    }

    /**
     * @dev Hash an order, returning the hash that a client must sign via EIP-712 including the message prefix
     * @param order Order to hash
     * @param nonce Nonce to hash
     * @return Hash of message prefix and order hash per Ethereum format
     */
    function hashToSign(Order memory order, uint nonce)
        internal
        pure
        returns (bytes32)
    {
        return keccak256(
            abi.encodePacked("\x19\x01", DOMAIN_SEPARATOR, hashOrder(order, nonce))
        );
    }

    /**
     * @dev Assert an order is valid and return its hash
     * @param order Order to validate
     * @param nonce Nonce to validate
     * @param sig ECDSA signature
     */
    function requireValidOrder(Order memory order, Sig memory sig, uint nonce)
        internal
        view
        returns (bytes32)
    {
        bytes32 hash = hashToSign(order, nonce);
        require(validateOrder(hash, order, sig));
        return hash;
    }

    /**
     * @dev Validate order parameters (does *not* check signature validity)
     * @param order Order to validate
     */
    function validateOrderParameters(Order memory order)
        internal
        view
        returns (bool)
    {
        /* Order must be targeted at this protocol version (this Exchange contract). */
        if (order.exchange != address(this)) {
            return false;
        }

        /* Order must have a maker. */
        if (order.maker == address(0)) {
            return false;
        }

        /* Order must possess valid sale kind parameter combination. */
        if (!SaleKindInterface.validateParameters(order.saleKind, order.expirationTime)) {
            return false;
        }

        /* If using the split fee method, order must have sufficient protocol fees. */
        if (order.feeMethod == FeeMethod.SplitFee && (order.makerProtocolFee < minimumMakerProtocolFee || order.takerProtocolFee < minimumTakerProtocolFee)) {
            return false;
        }

        return true;
    }

    /**
     * @dev Validate a provided previously approved / signed order, hash, and signature.
     * @param hash Order hash (already calculated, passed to avoid recalculation)
     * @param order Order to validate
     * @param sig ECDSA signature
     */
    function validateOrder(bytes32 hash, Order memory order, Sig memory sig)
        internal
        view
        returns (bool)
    {
        /* Not done in an if-conditional to prevent unnecessary ecrecover evaluation, which seems to happen even though it should short-circuit. */

        /* Order must have valid parameters. */
        if (!validateOrderParameters(order)) {
            return false;
        }

        /* Order must have not been canceled or already filled. */
        if (cancelledOrFinalized[hash]) {
            return false;
        }

        /* Return true if order has been previously approved with the current nonce */
        uint approvedOrderNoncePlusOne = _approvedOrdersByNonce[hash];
        if (approvedOrderNoncePlusOne != 0) {
            return approvedOrderNoncePlusOne == nonces[order.maker] + 1;
        }

        /* Prevent signature malleability and non-standard v values. */
        if (uint256(sig.s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return false;
        }
        if (sig.v != 27 && sig.v != 28) {
            return false;
        }

        /* recover via ECDSA, signed by maker (already verified as non-zero). */
        if (ecrecover(hash, sig.v, sig.r, sig.s) == order.maker) {
            return true;
        }

        /* fallback — attempt EIP-1271 isValidSignature check. */
        return _tryContractSignature(order.maker, hash, sig);
    }

    function _tryContractSignature(address orderMaker, bytes32 hash, Sig memory sig) internal view returns (bool) {
        bytes memory isValidSignatureData = abi.encodeWithSelector(
            _EIP_1271_MAGIC_VALUE,
            hash,
            abi.encodePacked(sig.r, sig.s, sig.v)
        );

        bytes4 result;

        // NOTE: solidity 0.4.x does not support STATICCALL outside of assembly
        assembly {
            let success := staticcall(           // perform a staticcall
                gas,                             // forward all available gas
                orderMaker,                      // call the order maker
                add(isValidSignatureData, 0x20), // calldata offset comes after length
                mload(isValidSignatureData),     // load calldata length
                0,                               // do not use memory for return data
                0                                // do not use memory for return data
            )

            if iszero(success) {                     // if the call fails
                returndatacopy(0, 0, returndatasize) // copy returndata buffer to memory
                revert(0, returndatasize)            // revert + pass through revert data
            }

            if eq(returndatasize, 0x20) {  // if returndata == 32 (one word)
                returndatacopy(0, 0, 0x20) // copy return data to memory in scratch space
                result := mload(0)         // load return data from memory to the stack
            }
        }

        return result == _EIP_1271_MAGIC_VALUE;
    }

    /**
     * @dev Determine if an order has been approved. Note that the order may not still
     * be valid in cases where the maker's nonce has been incremented.
     * @param hash Hash of the order
     * @return whether or not the order was approved.
     */
    function approvedOrders(bytes32 hash) public view returns (bool approved) {
        return _approvedOrdersByNonce[hash] != 0;
    }

    /**
     * @dev Approve an order and optionally mark it for orderbook inclusion. Must be called by the maker of the order
     * @param order Order to approve
     * @param orderbookInclusionDesired Whether orderbook providers should include the order in their orderbooks
     */
    function approveOrder(Order memory order, bool orderbookInclusionDesired)
        internal
    {
        /* CHECKS */

        /* Assert sender is authorized to approve order. */
        require(msg.sender == order.maker);

        /* Calculate order hash. */
        bytes32 hash = hashToSign(order, nonces[order.maker]);

        /* Assert order has not already been approved. */
        require(_approvedOrdersByNonce[hash] == 0);

        /* EFFECTS */

        /* Mark order as approved. */
        _approvedOrdersByNonce[hash] = nonces[order.maker] + 1;

        /* Log approval event. Must be split in two due to Solidity stack size limitations. */
        {
            emit OrderApprovedPartOne(hash, order.exchange, order.maker, order.taker, order.makerRelayerFee, order.takerRelayerFee, order.makerProtocolFee, order.takerProtocolFee, order.feeRecipient, order.feeMethod, order.side, order.saleKind, order.target);
        }
        {
            emit OrderApprovedPartTwo(hash, order.howToCall, order.calldata, order.replacementPattern, order.staticTarget, order.staticExtradata, order.paymentToken, order.basePrice, order.extra, order.listingTime, order.expirationTime, order.salt, orderbookInclusionDesired);
        }
    }

    /**
     * @dev Cancel an order, preventing it from being matched. Must be called by the maker of the order
     * @param order Order to cancel
     * @param nonce Nonce to cancel
     * @param sig ECDSA signature
     */
    function cancelOrder(Order memory order, Sig memory sig, uint nonce)
        internal
    {
        /* CHECKS */

        /* Calculate order hash. */
        bytes32 hash = requireValidOrder(order, sig, nonce);

        /* Assert sender is authorized to cancel order. */
        require(msg.sender == order.maker);

        /* EFFECTS */

        /* Mark order as cancelled, preventing it from being matched. */
        cancelledOrFinalized[hash] = true;

        /* Log cancel event. */
        emit OrderCancelled(hash);
    }

    /**
     * @dev Calculate the current price of an order (convenience function)
     * @param order Order to calculate the price of
     * @return The current price of the order
     */
    function calculateCurrentPrice (Order memory order)
        internal
        view
        returns (uint)
    {
        return SaleKindInterface.calculateFinalPrice(order.side, order.saleKind, order.basePrice, order.extra, order.listingTime, order.expirationTime);
    }

    /**
     * @dev Calculate the price two orders would match at, if in fact they would match (otherwise fail)
     * @param buy Buy-side order
     * @param sell Sell-side order
     * @return Match price
     */
    function calculateMatchPrice(Order memory buy, Order memory sell)
        view
        internal
        returns (uint)
    {
        /* Calculate sell price. */
        uint sellPrice = SaleKindInterface.calculateFinalPrice(sell.side, sell.saleKind, sell.basePrice, sell.extra, sell.listingTime, sell.expirationTime);

        /* Calculate buy price. */
        uint buyPrice = SaleKindInterface.calculateFinalPrice(buy.side, buy.saleKind, buy.basePrice, buy.extra, buy.listingTime, buy.expirationTime);

        /* Require price cross. */
        require(buyPrice >= sellPrice);

        /* Maker/taker priority. */
        return sell.feeRecipient != address(0) ? sellPrice : buyPrice;
    }

    /**
     * @dev Execute all ERC20 token / Ether transfers associated with an order match (fees and buyer => seller transfer)
     * @param buy Buy-side order
     * @param sell Sell-side order
     */
    function executeFundsTransfer(Order memory buy, Order memory sell)
        internal
        returns (uint)
    {
        /* Only payable in the special case of unwrapped Ether. */
        if (sell.paymentToken != address(0)) {
            require(msg.value == 0);
        }

        /* Calculate match price. */
        uint price = calculateMatchPrice(buy, sell);

        /* If paying using a token (not Ether), transfer tokens. This is done prior to fee payments to that a seller will have tokens before being charged fees. */
        if (price > 0 && sell.paymentToken != address(0)) {
            transferTokens(sell.paymentToken, buy.maker, sell.maker, price);
        }

        /* Amount that will be received by seller (for Ether). */
        uint receiveAmount = price;

        /* Amount that must be sent by buyer (for Ether). */
        uint requiredAmount = price;

        /* Determine maker/taker and charge fees accordingly. */
        if (sell.feeRecipient != address(0)) {
            /* Sell-side order is maker. */

            /* Assert taker fee is less than or equal to maximum fee specified by buyer. */
            require(sell.takerRelayerFee <= buy.takerRelayerFee);

            if (sell.feeMethod == FeeMethod.SplitFee) {
                /* Assert taker fee is less than or equal to maximum fee specified by buyer. */
                require(sell.takerProtocolFee <= buy.takerProtocolFee);

                /* Maker fees are deducted from the token amount that the maker receives. Taker fees are extra tokens that must be paid by the taker. */

                if (sell.makerRelayerFee > 0) {
                    uint makerRelayerFee = SafeMath.div(SafeMath.mul(sell.makerRelayerFee, price), INVERSE_BASIS_POINT);
                    if (sell.paymentToken == address(0)) {
                        receiveAmount = SafeMath.sub(receiveAmount, makerRelayerFee);
                        sell.feeRecipient.transfer(makerRelayerFee);
                    } else {
                        transferTokens(sell.paymentToken, sell.maker, sell.feeRecipient, makerRelayerFee);
                    }
                }

                if (sell.takerRelayerFee > 0) {
                    uint takerRelayerFee = SafeMath.div(SafeMath.mul(sell.takerRelayerFee, price), INVERSE_BASIS_POINT);
                    if (sell.paymentToken == address(0)) {
                        requiredAmount = SafeMath.add(requiredAmount, takerRelayerFee);
                        sell.feeRecipient.transfer(takerRelayerFee);
                    } else {
                        transferTokens(sell.paymentToken, buy.maker, sell.feeRecipient, takerRelayerFee);
                    }
                }

                if (sell.makerProtocolFee > 0) {
                    uint makerProtocolFee = SafeMath.div(SafeMath.mul(sell.makerProtocolFee, price), INVERSE_BASIS_POINT);
                    if (sell.paymentToken == address(0)) {
                        receiveAmount = SafeMath.sub(receiveAmount, makerProtocolFee);
                        protocolFeeRecipient.transfer(makerProtocolFee);
                    } else {
                        transferTokens(sell.paymentToken, sell.maker, protocolFeeRecipient, makerProtocolFee);
                    }
                }

                if (sell.takerProtocolFee > 0) {
                    uint takerProtocolFee = SafeMath.div(SafeMath.mul(sell.takerProtocolFee, price), INVERSE_BASIS_POINT);
                    if (sell.paymentToken == address(0)) {
                        requiredAmount = SafeMath.add(requiredAmount, takerProtocolFee);
                        protocolFeeRecipient.transfer(takerProtocolFee);
                    } else {
                        transferTokens(sell.paymentToken, buy.maker, protocolFeeRecipient, takerProtocolFee);
                    }
                }

            } else {
                /* Charge maker fee to seller. */
                chargeProtocolFee(sell.maker, sell.feeRecipient, sell.makerRelayerFee);

                /* Charge taker fee to buyer. */
                chargeProtocolFee(buy.maker, sell.feeRecipient, sell.takerRelayerFee);
            }
        } else {
            /* Buy-side order is maker. */

            /* Assert taker fee is less than or equal to maximum fee specified by seller. */
            require(buy.takerRelayerFee <= sell.takerRelayerFee);

            if (sell.feeMethod == FeeMethod.SplitFee) {
                /* The Exchange does not escrow Ether, so direct Ether can only be used to with sell-side maker / buy-side taker orders. */
                require(sell.paymentToken != address(0));

                /* Assert taker fee is less than or equal to maximum fee specified by seller. */
                require(buy.takerProtocolFee <= sell.takerProtocolFee);

                if (buy.makerRelayerFee > 0) {
                    makerRelayerFee = SafeMath.div(SafeMath.mul(buy.makerRelayerFee, price), INVERSE_BASIS_POINT);
                    transferTokens(sell.paymentToken, buy.maker, buy.feeRecipient, makerRelayerFee);
                }

                if (buy.takerRelayerFee > 0) {
                    takerRelayerFee = SafeMath.div(SafeMath.mul(buy.takerRelayerFee, price), INVERSE_BASIS_POINT);
                    transferTokens(sell.paymentToken, sell.maker, buy.feeRecipient, takerRelayerFee);
                }

                if (buy.makerProtocolFee > 0) {
                    makerProtocolFee = SafeMath.div(SafeMath.mul(buy.makerProtocolFee, price), INVERSE_BASIS_POINT);
                    transferTokens(sell.paymentToken, buy.maker, protocolFeeRecipient, makerProtocolFee);
                }

                if (buy.takerProtocolFee > 0) {
                    takerProtocolFee = SafeMath.div(SafeMath.mul(buy.takerProtocolFee, price), INVERSE_BASIS_POINT);
                    transferTokens(sell.paymentToken, sell.maker, protocolFeeRecipient, takerProtocolFee);
                }

            } else {
                /* Charge maker fee to buyer. */
                chargeProtocolFee(buy.maker, buy.feeRecipient, buy.makerRelayerFee);

                /* Charge taker fee to seller. */
                chargeProtocolFee(sell.maker, buy.feeRecipient, buy.takerRelayerFee);
            }
        }

        if (sell.paymentToken == address(0)) {
            /* Special-case Ether, order must be matched by buyer. */
            require(msg.value >= requiredAmount);
            sell.maker.transfer(receiveAmount);
            /* Allow overshoot for variable-price auctions, refund difference. */
            uint diff = SafeMath.sub(msg.value, requiredAmount);
            if (diff > 0) {
                buy.maker.transfer(diff);
            }
        }

        /* This contract should never hold Ether, however, we cannot assert this, since it is impossible to prevent anyone from sending Ether e.g. with selfdestruct. */

        return price;
    }

    /**
     * @dev Return whether or not two orders can be matched with each other by basic parameters (does not check order signatures / calldata or perform static calls)
     * @param buy Buy-side order
     * @param sell Sell-side order
     * @return Whether or not the two orders can be matched
     */
    function ordersCanMatch(Order memory buy, Order memory sell)
        internal
        view
        returns (bool)
    {
        return (
            /* Must be opposite-side. */
            (buy.side == SaleKindInterface.Side.Buy && sell.side == SaleKindInterface.Side.Sell) &&
            /* Must use same fee method. */
            (buy.feeMethod == sell.feeMethod) &&
            /* Must use same payment token. */
            (buy.paymentToken == sell.paymentToken) &&
            /* Must match maker/taker addresses. */
            (sell.taker == address(0) || sell.taker == buy.maker) &&
            (buy.taker == address(0) || buy.taker == sell.maker) &&
            /* One must be maker and the other must be taker (no bool XOR in Solidity). */
            ((sell.feeRecipient == address(0) && buy.feeRecipient != address(0)) || (sell.feeRecipient != address(0) && buy.feeRecipient == address(0))) &&
            /* Must match target. */
            (buy.target == sell.target) &&
            /* Must match howToCall. */
            (buy.howToCall == sell.howToCall) &&
            /* Buy-side order must be settleable. */
            SaleKindInterface.canSettleOrder(buy.listingTime, buy.expirationTime) &&
            /* Sell-side order must be settleable. */
            SaleKindInterface.canSettleOrder(sell.listingTime, sell.expirationTime)
        );
    }

    /**
     * @dev Atomically match two orders, ensuring validity of the match, and execute all associated state transitions. Protected against reentrancy by a contract-global lock.
     * @param buy Buy-side order
     * @param buySig Buy-side order signature
     * @param sell Sell-side order
     * @param sellSig Sell-side order signature
     */
    function atomicMatch(Order memory buy, Sig memory buySig, Order memory sell, Sig memory sellSig, bytes32 metadata)
        internal
        reentrancyGuard
    {
        /* CHECKS */

        /* Ensure buy order validity and calculate hash if necessary. */
        bytes32 buyHash;
        if (buy.maker == msg.sender) {
            require(validateOrderParameters(buy));
        } else {
            buyHash = _requireValidOrderWithNonce(buy, buySig);
        }

        /* Ensure sell order validity and calculate hash if necessary. */
        bytes32 sellHash;
        if (sell.maker == msg.sender) {
            require(validateOrderParameters(sell));
        } else {
            sellHash = _requireValidOrderWithNonce(sell, sellSig);
        }

        /* Must be matchable. */
        require(ordersCanMatch(buy, sell));

        /* Target must exist (prevent malicious selfdestructs just prior to order settlement). */
        uint size;
        address target = sell.target;
        assembly {
            size := extcodesize(target)
        }
        require(size > 0);

        /* Must match calldata after replacement, if specified. */
        if (buy.replacementPattern.length > 0) {
          ArrayUtils.guardedArrayReplace(buy.calldata, sell.calldata, buy.replacementPattern);
        }
        if (sell.replacementPattern.length > 0) {
          ArrayUtils.guardedArrayReplace(sell.calldata, buy.calldata, sell.replacementPattern);
        }
        require(ArrayUtils.arrayEq(buy.calldata, sell.calldata));

        /* Retrieve delegateProxy contract. */
        OwnableDelegateProxy delegateProxy = registry.proxies(sell.maker);

        /* Proxy must exist. */
        require(delegateProxy != address(0));

        /* Access the passthrough AuthenticatedProxy. */
        AuthenticatedProxy proxy = AuthenticatedProxy(delegateProxy);

        /* EFFECTS */

        /* Mark previously signed or approved orders as finalized. */
        if (msg.sender != buy.maker) {
            cancelledOrFinalized[buyHash] = true;
        }
        if (msg.sender != sell.maker) {
            cancelledOrFinalized[sellHash] = true;
        }

        /* INTERACTIONS */

        /* Execute funds transfer and pay fees. */
        uint price = executeFundsTransfer(buy, sell);

        /* Assert implementation. */
        require(delegateProxy.implementation() == registry.delegateProxyImplementation());

        /* Execute specified call through proxy. */
        require(proxy.proxy(sell.target, sell.howToCall, sell.calldata));

        /* Static calls are intentionally done after the effectful call so they can check resulting state. */

        /* Handle buy-side static call if specified. */
        if (buy.staticTarget != address(0)) {
            require(staticCall(buy.staticTarget, sell.calldata, buy.staticExtradata));
        }

        /* Handle sell-side static call if specified. */
        if (sell.staticTarget != address(0)) {
            require(staticCall(sell.staticTarget, sell.calldata, sell.staticExtradata));
        }

        /* Log match event. */
        emit OrdersMatched(buyHash, sellHash, sell.feeRecipient != address(0) ? sell.maker : buy.maker, sell.feeRecipient != address(0) ? buy.maker : sell.maker, price, metadata);
    }

    function _requireValidOrderWithNonce(Order memory order, Sig memory sig) internal view returns (bytes32) {
        return requireValidOrder(order, sig, nonces[order.maker]);
    }
}

contract Exchange is ExchangeCore {

    /**
     * @dev Call guardedArrayReplace - library function exposed for testing.
     */
    function guardedArrayReplace(bytes array, bytes desired, bytes mask)
        public
        pure
        returns (bytes)
    {
        ArrayUtils.guardedArrayReplace(array, desired, mask);
        return array;
    }

    /**
     * @dev Call calculateFinalPrice - library function exposed for testing.
     */
    function calculateFinalPrice(SaleKindInterface.Side side, SaleKindInterface.SaleKind saleKind, uint basePrice, uint extra, uint listingTime, uint expirationTime)
        public
        view
        returns (uint)
    {
        return SaleKindInterface.calculateFinalPrice(side, saleKind, basePrice, extra, listingTime, expirationTime);
    }

    /**
     * @dev Call hashOrder - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function hashOrder_(
        address[7] addrs,
        uint[9] uints,
        FeeMethod feeMethod,
        SaleKindInterface.Side side,
        SaleKindInterface.SaleKind saleKind,
        AuthenticatedProxy.HowToCall howToCall,
        bytes calldata,
        bytes replacementPattern,
        bytes staticExtradata)
        public
        view
        returns (bytes32)
    {
        return hashOrder(
          Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], feeMethod, side, saleKind, addrs[4], howToCall, calldata, replacementPattern, addrs[5], staticExtradata, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]),
          nonces[addrs[1]]
        );
    }

    /**
     * @dev Call hashToSign - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function hashToSign_(
        address[7] addrs,
        uint[9] uints,
        FeeMethod feeMethod,
        SaleKindInterface.Side side,
        SaleKindInterface.SaleKind saleKind,
        AuthenticatedProxy.HowToCall howToCall,
        bytes calldata,
        bytes replacementPattern,
        bytes staticExtradata)
        public
        view
        returns (bytes32)
    {
        return hashToSign(
          Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], feeMethod, side, saleKind, addrs[4], howToCall, calldata, replacementPattern, addrs[5], staticExtradata, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]),
          nonces[addrs[1]]
        );
    }

    /**
     * @dev Call validateOrderParameters - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function validateOrderParameters_ (
        address[7] addrs,
        uint[9] uints,
        FeeMethod feeMethod,
        SaleKindInterface.Side side,
        SaleKindInterface.SaleKind saleKind,
        AuthenticatedProxy.HowToCall howToCall,
        bytes calldata,
        bytes replacementPattern,
        bytes staticExtradata)
        view
        public
        returns (bool)
    {
        Order memory order = Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], feeMethod, side, saleKind, addrs[4], howToCall, calldata, replacementPattern, addrs[5], staticExtradata, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]);
        return validateOrderParameters(
          order
        );
    }

    /**
     * @dev Call validateOrder - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function validateOrder_ (
        address[7] addrs,
        uint[9] uints,
        FeeMethod feeMethod,
        SaleKindInterface.Side side,
        SaleKindInterface.SaleKind saleKind,
        AuthenticatedProxy.HowToCall howToCall,
        bytes calldata,
        bytes replacementPattern,
        bytes staticExtradata,
        uint8 v,
        bytes32 r,
        bytes32 s)
        view
        public
        returns (bool)
    {
        Order memory order = Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], feeMethod, side, saleKind, addrs[4], howToCall, calldata, replacementPattern, addrs[5], staticExtradata, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]);
        return validateOrder(
          hashToSign(order, nonces[order.maker]),
          order,
          Sig(v, r, s)
        );
    }

    /**
     * @dev Call approveOrder - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function approveOrder_ (
        address[7] addrs,
        uint[9] uints,
        FeeMethod feeMethod,
        SaleKindInterface.Side side,
        SaleKindInterface.SaleKind saleKind,
        AuthenticatedProxy.HowToCall howToCall,
        bytes calldata,
        bytes replacementPattern,
        bytes staticExtradata,
        bool orderbookInclusionDesired)
        public
    {
        Order memory order = Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], feeMethod, side, saleKind, addrs[4], howToCall, calldata, replacementPattern, addrs[5], staticExtradata, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]);
        return approveOrder(order, orderbookInclusionDesired);
    }

    /**
     * @dev Call cancelOrder - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function cancelOrder_(
        address[7] addrs,
        uint[9] uints,
        FeeMethod feeMethod,
        SaleKindInterface.Side side,
        SaleKindInterface.SaleKind saleKind,
        AuthenticatedProxy.HowToCall howToCall,
        bytes calldata,
        bytes replacementPattern,
        bytes staticExtradata,
        uint8 v,
        bytes32 r,
        bytes32 s)
        public
    {
        Order memory order = Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], feeMethod, side, saleKind, addrs[4], howToCall, calldata, replacementPattern, addrs[5], staticExtradata, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]);
        return cancelOrder(
          order,
          Sig(v, r, s),
          nonces[order.maker]
        );
    }

    /**
     * @dev Call cancelOrder, supplying a specific nonce — enables cancelling orders
     that were signed with nonces greater than the current nonce.
     */
    function cancelOrderWithNonce_(
        address[7] addrs,
        uint[9] uints,
        FeeMethod feeMethod,
        SaleKindInterface.Side side,
        SaleKindInterface.SaleKind saleKind,
        AuthenticatedProxy.HowToCall howToCall,
        bytes calldata,
        bytes replacementPattern,
        bytes staticExtradata,
        uint8 v,
        bytes32 r,
        bytes32 s,
        uint nonce)
        public
    {
        Order memory order = Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], feeMethod, side, saleKind, addrs[4], howToCall, calldata, replacementPattern, addrs[5], staticExtradata, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]);
        return cancelOrder(
          order,
          Sig(v, r, s),
          nonce
        );
    }

    /**
     * @dev Call calculateCurrentPrice - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function calculateCurrentPrice_(
        address[7] addrs,
        uint[9] uints,
        FeeMethod feeMethod,
        SaleKindInterface.Side side,
        SaleKindInterface.SaleKind saleKind,
        AuthenticatedProxy.HowToCall howToCall,
        bytes calldata,
        bytes replacementPattern,
        bytes staticExtradata)
        public
        view
        returns (uint)
    {
        return calculateCurrentPrice(
          Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], feeMethod, side, saleKind, addrs[4], howToCall, calldata, replacementPattern, addrs[5], staticExtradata, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8])
        );
    }

    /**
     * @dev Call ordersCanMatch - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function ordersCanMatch_(
        address[14] addrs,
        uint[18] uints,
        uint8[8] feeMethodsSidesKindsHowToCalls,
        bytes calldataBuy,
        bytes calldataSell,
        bytes replacementPatternBuy,
        bytes replacementPatternSell,
        bytes staticExtradataBuy,
        bytes staticExtradataSell)
        public
        view
        returns (bool)
    {
        Order memory buy = Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], FeeMethod(feeMethodsSidesKindsHowToCalls[0]), SaleKindInterface.Side(feeMethodsSidesKindsHowToCalls[1]), SaleKindInterface.SaleKind(feeMethodsSidesKindsHowToCalls[2]), addrs[4], AuthenticatedProxy.HowToCall(feeMethodsSidesKindsHowToCalls[3]), calldataBuy, replacementPatternBuy, addrs[5], staticExtradataBuy, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]);
        Order memory sell = Order(addrs[7], addrs[8], addrs[9], uints[9], uints[10], uints[11], uints[12], addrs[10], FeeMethod(feeMethodsSidesKindsHowToCalls[4]), SaleKindInterface.Side(feeMethodsSidesKindsHowToCalls[5]), SaleKindInterface.SaleKind(feeMethodsSidesKindsHowToCalls[6]), addrs[11], AuthenticatedProxy.HowToCall(feeMethodsSidesKindsHowToCalls[7]), calldataSell, replacementPatternSell, addrs[12], staticExtradataSell, ERC20(addrs[13]), uints[13], uints[14], uints[15], uints[16], uints[17]);
        return ordersCanMatch(
          buy,
          sell
        );
    }

    /**
     * @dev Return whether or not two orders' calldata specifications can match
     * @param buyCalldata Buy-side order calldata
     * @param buyReplacementPattern Buy-side order calldata replacement mask
     * @param sellCalldata Sell-side order calldata
     * @param sellReplacementPattern Sell-side order calldata replacement mask
     * @return Whether the orders' calldata can be matched
     */
    function orderCalldataCanMatch(bytes buyCalldata, bytes buyReplacementPattern, bytes sellCalldata, bytes sellReplacementPattern)
        public
        pure
        returns (bool)
    {
        if (buyReplacementPattern.length > 0) {
          ArrayUtils.guardedArrayReplace(buyCalldata, sellCalldata, buyReplacementPattern);
        }
        if (sellReplacementPattern.length > 0) {
          ArrayUtils.guardedArrayReplace(sellCalldata, buyCalldata, sellReplacementPattern);
        }
        return ArrayUtils.arrayEq(buyCalldata, sellCalldata);
    }

    /**
     * @dev Call calculateMatchPrice - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function calculateMatchPrice_(
        address[14] addrs,
        uint[18] uints,
        uint8[8] feeMethodsSidesKindsHowToCalls,
        bytes calldataBuy,
        bytes calldataSell,
        bytes replacementPatternBuy,
        bytes replacementPatternSell,
        bytes staticExtradataBuy,
        bytes staticExtradataSell)
        public
        view
        returns (uint)
    {
        Order memory buy = Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], FeeMethod(feeMethodsSidesKindsHowToCalls[0]), SaleKindInterface.Side(feeMethodsSidesKindsHowToCalls[1]), SaleKindInterface.SaleKind(feeMethodsSidesKindsHowToCalls[2]), addrs[4], AuthenticatedProxy.HowToCall(feeMethodsSidesKindsHowToCalls[3]), calldataBuy, replacementPatternBuy, addrs[5], staticExtradataBuy, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]);
        Order memory sell = Order(addrs[7], addrs[8], addrs[9], uints[9], uints[10], uints[11], uints[12], addrs[10], FeeMethod(feeMethodsSidesKindsHowToCalls[4]), SaleKindInterface.Side(feeMethodsSidesKindsHowToCalls[5]), SaleKindInterface.SaleKind(feeMethodsSidesKindsHowToCalls[6]), addrs[11], AuthenticatedProxy.HowToCall(feeMethodsSidesKindsHowToCalls[7]), calldataSell, replacementPatternSell, addrs[12], staticExtradataSell, ERC20(addrs[13]), uints[13], uints[14], uints[15], uints[16], uints[17]);
        return calculateMatchPrice(
          buy,
          sell
        );
    }

    /**
     * @dev Call atomicMatch - Solidity ABI encoding limitation workaround, hopefully temporary.
     */
    function atomicMatch_(
        address[14] addrs,
        uint[18] uints,
        uint8[8] feeMethodsSidesKindsHowToCalls,
        bytes calldataBuy,
        bytes calldataSell,
        bytes replacementPatternBuy,
        bytes replacementPatternSell,
        bytes staticExtradataBuy,
        bytes staticExtradataSell,
        uint8[2] vs,
        bytes32[5] rssMetadata)
        public
        payable
    {

        return atomicMatch(
          Order(addrs[0], addrs[1], addrs[2], uints[0], uints[1], uints[2], uints[3], addrs[3], FeeMethod(feeMethodsSidesKindsHowToCalls[0]), SaleKindInterface.Side(feeMethodsSidesKindsHowToCalls[1]), SaleKindInterface.SaleKind(feeMethodsSidesKindsHowToCalls[2]), addrs[4], AuthenticatedProxy.HowToCall(feeMethodsSidesKindsHowToCalls[3]), calldataBuy, replacementPatternBuy, addrs[5], staticExtradataBuy, ERC20(addrs[6]), uints[4], uints[5], uints[6], uints[7], uints[8]),
          Sig(vs[0], rssMetadata[0], rssMetadata[1]),
          Order(addrs[7], addrs[8], addrs[9], uints[9], uints[10], uints[11], uints[12], addrs[10], FeeMethod(feeMethodsSidesKindsHowToCalls[4]), SaleKindInterface.Side(feeMethodsSidesKindsHowToCalls[5]), SaleKindInterface.SaleKind(feeMethodsSidesKindsHowToCalls[6]), addrs[11], AuthenticatedProxy.HowToCall(feeMethodsSidesKindsHowToCalls[7]), calldataSell, replacementPatternSell, addrs[12], staticExtradataSell, ERC20(addrs[13]), uints[13], uints[14], uints[15], uints[16], uints[17]),
          Sig(vs[1], rssMetadata[2], rssMetadata[3]),
          rssMetadata[4]
        );
    }

}

contract WyvernExchangeWithBulkCancellations is Exchange {
    string public constant codename = "Bulk Smash";

    /**
     * @dev Initialize a WyvernExchange instance
     * @param registryAddress Address of the registry instance which this Exchange instance will use
     * @param tokenAddress Address of the token used for protocol fees
     */
    constructor (ProxyRegistry registryAddress, TokenTransferProxy tokenTransferProxyAddress, ERC20 tokenAddress, address protocolFeeAddress) public {
        registry = registryAddress;
        tokenTransferProxy = tokenTransferProxyAddress;
        exchangeToken = tokenAddress;
        protocolFeeRecipient = protocolFeeAddress;
        owner = msg.sender;
    }
}

library SaleKindInterface {

    /**
     * Side: buy or sell.
     */
    enum Side { Buy, Sell }

    /**
     * Currently supported kinds of sale: fixed price, Dutch auction.
     * English auctions cannot be supported without stronger escrow guarantees.
     * Future interesting options: Vickrey auction, nonlinear Dutch auctions.
     */
    enum SaleKind { FixedPrice, DutchAuction }

    /**
     * @dev Check whether the parameters of a sale are valid
     * @param saleKind Kind of sale
     * @param expirationTime Order expiration time
     * @return Whether the parameters were valid
     */
    function validateParameters(SaleKind saleKind, uint expirationTime)
        pure
        internal
        returns (bool)
    {
        /* Auctions must have a set expiration date. */
        return (saleKind == SaleKind.FixedPrice || expirationTime > 0);
    }

    /**
     * @dev Return whether or not an order can be settled
     * @dev Precondition: parameters have passed validateParameters
     * @param listingTime Order listing time
     * @param expirationTime Order expiration time
     */
    function canSettleOrder(uint listingTime, uint expirationTime)
        view
        internal
        returns (bool)
    {
        return (listingTime < now) && (expirationTime == 0 || now < expirationTime);
    }

    /**
     * @dev Calculate the settlement price of an order
     * @dev Precondition: parameters have passed validateParameters.
     * @param side Order side
     * @param saleKind Method of sale
     * @param basePrice Order base price
     * @param extra Order extra price data
     * @param listingTime Order listing time
     * @param expirationTime Order expiration time
     */
    function calculateFinalPrice(Side side, SaleKind saleKind, uint basePrice, uint extra, uint listingTime, uint expirationTime)
        view
        internal
        returns (uint finalPrice)
    {
        if (saleKind == SaleKind.FixedPrice) {
            return basePrice;
        } else if (saleKind == SaleKind.DutchAuction) {
            uint diff = SafeMath.div(SafeMath.mul(extra, SafeMath.sub(now, listingTime)), SafeMath.sub(expirationTime, listingTime));
            if (side == Side.Sell) {
                /* Sell-side - start price: basePrice. End price: basePrice - extra. */
                return SafeMath.sub(basePrice, diff);
            } else {
                /* Buy-side - start price: basePrice. End price: basePrice + extra. */
                return SafeMath.add(basePrice, diff);
            }
        }
    }

}

contract ProxyRegistry is Ownable {

    /* DelegateProxy implementation contract. Must be initialized. */
    address public delegateProxyImplementation;

    /* Authenticated proxies by user. */
    mapping(address => OwnableDelegateProxy) public proxies;

    /* Contracts pending access. */
    mapping(address => uint) public pending;

    /* Contracts allowed to call those proxies. */
    mapping(address => bool) public contracts;

    /* Delay period for adding an authenticated contract.
       This mitigates a particular class of potential attack on the Wyvern DAO (which owns this registry) - if at any point the value of assets held by proxy contracts exceeded the value of half the WYV supply (votes in the DAO),
       a malicious but rational attacker could buy half the Wyvern and grant themselves access to all the proxy contracts. A delay period renders this attack nonthreatening - given two weeks, if that happened, users would have
       plenty of time to notice and transfer their assets.
    */
    uint public DELAY_PERIOD = 2 weeks;

    /**
     * Start the process to enable access for specified contract. Subject to delay period.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address to which to grant permissions
     */
    function startGrantAuthentication (address addr)
        public
        onlyOwner
    {
        require(!contracts[addr] && pending[addr] == 0);
        pending[addr] = now;
    }

    /**
     * End the process to nable access for specified contract after delay period has passed.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address to which to grant permissions
     */
    function endGrantAuthentication (address addr)
        public
        onlyOwner
    {
        require(!contracts[addr] && pending[addr] != 0 && ((pending[addr] + DELAY_PERIOD) < now));
        pending[addr] = 0;
        contracts[addr] = true;
    }

    /**
     * Revoke access for specified contract. Can be done instantly.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address of which to revoke permissions
     */
    function revokeAuthentication (address addr)
        public
        onlyOwner
    {
        contracts[addr] = false;
    }

    /**
     * Register a proxy contract with this registry
     *
     * @dev Must be called by the user which the proxy is for, creates a new AuthenticatedProxy
     * @return New AuthenticatedProxy contract
     */
    function registerProxy()
        public
        returns (OwnableDelegateProxy proxy)
    {
        require(proxies[msg.sender] == address(0));
        proxy = new OwnableDelegateProxy(msg.sender, delegateProxyImplementation, abi.encodeWithSignature("initialize(address,address)", msg.sender, address(this)));
        proxies[msg.sender] = proxy;
        return proxy;
    }

}

contract TokenTransferProxy {

    /* Authentication registry. */
    ProxyRegistry public registry;

    /**
     * Call ERC20 `transferFrom`
     *
     * @dev Authenticated contract only
     * @param token ERC20 token address
     * @param from From address
     * @param to To address
     * @param amount Transfer amount
     */
    function transferFrom(address token, address from, address to, uint amount)
        public
        returns (bool)
    {
        require(registry.contracts(msg.sender));
        return ERC20(token).transferFrom(from, to, amount);
    }

}

contract OwnedUpgradeabilityStorage {

  // Current implementation
  address internal _implementation;

  // Owner of the contract
  address private _upgradeabilityOwner;

  /**
   * @dev Tells the address of the owner
   * @return the address of the owner
   */
  function upgradeabilityOwner() public view returns (address) {
    return _upgradeabilityOwner;
  }

  /**
   * @dev Sets the address of the owner
   */
  function setUpgradeabilityOwner(address newUpgradeabilityOwner) internal {
    _upgradeabilityOwner = newUpgradeabilityOwner;
  }

  /**
  * @dev Tells the address of the current implementation
  * @return address of the current implementation
  */
  function implementation() public view returns (address) {
    return _implementation;
  }

  /**
  * @dev Tells the proxy type (EIP 897)
  * @return Proxy type, 2 for forwarding proxy
  */
  function proxyType() public pure returns (uint256 proxyTypeId) {
    return 2;
  }
}

contract AuthenticatedProxy is TokenRecipient, OwnedUpgradeabilityStorage {

    /* Whether initialized. */
    bool initialized = false;

    /* Address which owns this proxy. */
    address public user;

    /* Associated registry with contract authentication information. */
    ProxyRegistry public registry;

    /* Whether access has been revoked. */
    bool public revoked;

    /* Delegate call could be used to atomically transfer multiple assets owned by the proxy contract with one order. */
    enum HowToCall { Call, DelegateCall }

    /* Event fired when the proxy access is revoked or unrevoked. */
    event Revoked(bool revoked);

    /**
     * Initialize an AuthenticatedProxy
     *
     * @param addrUser Address of user on whose behalf this proxy will act
     * @param addrRegistry Address of ProxyRegistry contract which will manage this proxy
     */
    function initialize (address addrUser, ProxyRegistry addrRegistry)
        public
    {
        require(!initialized);
        initialized = true;
        user = addrUser;
        registry = addrRegistry;
    }

    /**
     * Set the revoked flag (allows a user to revoke ProxyRegistry access)
     *
     * @dev Can be called by the user only
     * @param revoke Whether or not to revoke access
     */
    function setRevoke(bool revoke)
        public
    {
        require(msg.sender == user);
        revoked = revoke;
        emit Revoked(revoke);
    }

    /**
     * Execute a message call from the proxy contract
     *
     * @dev Can be called by the user, or by a contract authorized by the registry as long as the user has not revoked access
     * @param dest Address to which the call will be sent
     * @param howToCall Which kind of call to make
     * @param calldata Calldata to send
     * @return Result of the call (success or failure)
     */
    function proxy(address dest, HowToCall howToCall, bytes calldata)
        public
        returns (bool result)
    {
        require(msg.sender == user || (!revoked && registry.contracts(msg.sender)));
        if (howToCall == HowToCall.Call) {
            result = dest.call(calldata);
        } else if (howToCall == HowToCall.DelegateCall) {
            result = dest.delegatecall(calldata);
        }
        return result;
    }

    /**
     * Execute a message call and assert success
     *
     * @dev Same functionality as `proxy`, just asserts the return value
     * @param dest Address to which the call will be sent
     * @param howToCall What kind of call to make
     * @param calldata Calldata to send
     */
    function proxyAssert(address dest, HowToCall howToCall, bytes calldata)
        public
    {
        require(proxy(dest, howToCall, calldata));
    }

}

contract Proxy {

  /**
  * @dev Tells the address of the implementation where every call will be delegated.
  * @return address of the implementation to which it will be delegated
  */
  function implementation() public view returns (address);

  /**
  * @dev Tells the type of proxy (EIP 897)
  * @return Type of proxy, 2 for upgradeable proxy
  */
  function proxyType() public pure returns (uint256 proxyTypeId);

  /**
  * @dev Fallback function allowing to perform a delegatecall to the given implementation.
  * This function will return whatever the implementation call returns
  */
  function () payable public {
    address _impl = implementation();
    require(_impl != address(0));

    assembly {
      let ptr := mload(0x40)
      calldatacopy(ptr, 0, calldatasize)
      let result := delegatecall(gas, _impl, ptr, calldatasize, 0, 0)
      let size := returndatasize
      returndatacopy(ptr, 0, size)

      switch result
      case 0 { revert(ptr, size) }
      default { return(ptr, size) }
    }
  }
}

contract OwnedUpgradeabilityProxy is Proxy, OwnedUpgradeabilityStorage {
  /**
  * @dev Event to show ownership has been transferred
  * @param previousOwner representing the address of the previous owner
  * @param newOwner representing the address of the new owner
  */
  event ProxyOwnershipTransferred(address previousOwner, address newOwner);

  /**
  * @dev This event will be emitted every time the implementation gets upgraded
  * @param implementation representing the address of the upgraded implementation
  */
  event Upgraded(address indexed implementation);

  /**
  * @dev Upgrades the implementation address
  * @param implementation representing the address of the new implementation to be set
  */
  function _upgradeTo(address implementation) internal {
    require(_implementation != implementation);
    _implementation = implementation;
    emit Upgraded(implementation);
  }

  /**
  * @dev Throws if called by any account other than the owner.
  */
  modifier onlyProxyOwner() {
    require(msg.sender == proxyOwner());
    _;
  }

  /**
   * @dev Tells the address of the proxy owner
   * @return the address of the proxy owner
   */
  function proxyOwner() public view returns (address) {
    return upgradeabilityOwner();
  }

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferProxyOwnership(address newOwner) public onlyProxyOwner {
    require(newOwner != address(0));
    emit ProxyOwnershipTransferred(proxyOwner(), newOwner);
    setUpgradeabilityOwner(newOwner);
  }

  /**
   * @dev Allows the upgradeability owner to upgrade the current implementation of the proxy.
   * @param implementation representing the address of the new implementation to be set.
   */
  function upgradeTo(address implementation) public onlyProxyOwner {
    _upgradeTo(implementation);
  }

  /**
   * @dev Allows the upgradeability owner to upgrade the current implementation of the proxy
   * and delegatecall the new implementation for initialization.
   * @param implementation representing the address of the new implementation to be set.
   * @param data represents the msg.data to bet sent in the low level call. This parameter may include the function
   * signature of the implementation to be called with the needed payload
   */
  function upgradeToAndCall(address implementation, bytes data) payable public onlyProxyOwner {
    upgradeTo(implementation);
    require(address(this).delegatecall(data));
  }
}

contract OwnableDelegateProxy is OwnedUpgradeabilityProxy {

    constructor(address owner, address initialImplementation, bytes calldata)
        public
    {
        setUpgradeabilityOwner(owner);
        _upgradeTo(initialImplementation);
        require(initialImplementation.delegatecall(calldata));
    }

}

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;
import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "./MultisigOwnable.sol";
import "@chainlink/contracts/src/v0.8/VRFConsumerBase.sol";
import "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";
import "./ERC721A.sol";
import "./BatchReveal.sol";
/*
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:::::::::: j               ' ´                   ｀ ヽ.      ,:::::::::::。::::::::::::::::::
::::::::::!              ´                           ヽ      ,:::::::::☆:::::::::::::::::::
::::::::: !             ´      ＿                ＿   ヽ     !::::::::::::::::::::::::::::::
::::::::: !            |  γ  =（   ヽ         : ' =::（ ヽ|     !:::::::::::::::::::::::::::::
::::::::: !            | 〈 ん:::☆:j j       ! ん:☆:::ﾊ       ::::::::::::::::::::::::::::::
::::::::: !            |  弋:::::.ﾉ ﾉ        ヾ:::::ﾉ ﾉ |     ::::::::::::::::::::::::::::::
:::::::::::'           |    ゝ  -  '     人    -    '  ﾉ     j::::::::::::::::::::::::::::::
:::::::::::,            ヽ                            ,     j::::☆::::::::::::::::::::::::::
::::::::::::,            ' ､                      , ／     ﾉ::::::::::::::::::::::::::::::::
::::::::::::::＼             ｰ--------------- '         ,':::::::::::::::::::::::::::::::::
::::☆:::::::::::ヽ                                    ／:::::::::::::::::::::::::::::::::::
:::::::::::::::::::7                :::::::::::::::＜::::::::::::::::::::::::::::::::::::::
:::::::::::::::::::r´                   :::::::::::::ヽ::::::::::::::::::::::::::::::::::::
::::::::::::::::::/                               :::::ヽ::::::::::::::::::::::::::::::::::
*/
// IMPORTANT: _burn() must never be called
contract Tubbies is ERC721A, MultisigOwnable, VRFConsumerBase, BatchReveal {
    using Strings for uint256;
    bytes32 immutable public merkleRoot;
    uint immutable public startSaleTimestamp;
    string public baseURI;
    string public unrevealedURI;
    bool public finalized = false;
    bool public useFancyMath = true;
    bool public airdropped = false;
    // Constants from https://docs.chain.link/docs/vrf-contracts/
    bytes32 immutable private s_keyHash;
    address immutable private linkToken;
    address immutable private linkCoordinator;
    constructor(bytes32 _merkleRoot, string memory _baseURI, string memory _unrevealedURI, bytes32 _s_keyHash, address _linkToken, address _linkCoordinator)
        ERC721A("Tubby Cats", "TUBBY")
        VRFConsumerBase(_linkCoordinator, _linkToken)
    {
        linkToken = _linkToken;
        linkCoordinator = _linkCoordinator;
        s_keyHash = _s_keyHash;
        merkleRoot = _merkleRoot;
        startSaleTimestamp = block.timestamp + 2 days;
        unrevealedURI = _unrevealedURI;
        baseURI = _baseURI;
    }
    function airdrop(address[] memory airdrops) external onlyRealOwner{
        require(airdropped == false, "already airdropped");
        for(uint i=0; i<airdrops.length; i++){
            _mint(airdrops[i], 1, '', false);
        }
        airdropped = true;
    }
    function setParams(string memory newBaseURI, string memory newUnrevealedURI, bool newFinal, bool newUseFancyMath) external onlyRealOwner {
        require(finalized == false, "final");
        baseURI = newBaseURI;
        unrevealedURI = newUnrevealedURI;
        finalized = newFinal;
        useFancyMath = newUseFancyMath;
    }
    function retrieveFunds(address payable to) external onlyRealOwner {
        to.transfer(address(this).balance);
    }
    // SALE
    function toBytes32(address addr) pure internal returns (bytes32){
        return bytes32(uint256(uint160(addr)));
    }
    // CAUTION: Never introduce any kind of batch processing for mint() or mintFromSale() since then people can
    // execute the same bug that appeared on sushi's bitDAO auction
    // There are some issues with merkle trees such as pre-image attacks or possibly duplicated leaves on
    // unbalanced trees, but here we protect against them by checking against msg.sender and only allowing each account to claim once
    // See https://github.com/miguelmota/merkletreejs#notes for more info
    mapping(address=>bool) public claimed;
    function mint(bytes32[] calldata _merkleProof) public payable {
        require(MerkleProof.verify(_merkleProof, merkleRoot, toBytes32(msg.sender)) == true, "wrong merkle proof");
        require(claimed[msg.sender] == false, "already claimed");
        claimed[msg.sender] = true;
        require(msg.value == 0.1 ether, "wrong payment");
        _mint(msg.sender, 1, '', false);
        require(totalSupply() <= TOKEN_LIMIT, "limit reached");
    }
    function mintFromSale(uint tubbiesToMint) public payable {
        require(block.timestamp > startSaleTimestamp, "Public sale hasn't started yet");
        require(tubbiesToMint <= 5, "Only up to 5 tubbies can be minted at once");
        uint cost;
        unchecked {
            cost = tubbiesToMint * 0.1 ether;
        }
        require(msg.value == cost, "wrong payment");
        _mint(msg.sender, tubbiesToMint, '', false);
        require(totalSupply() <= TOKEN_LIMIT, "limit reached");
    }
    // RANDOMIZATION
    uint public lastTokenRevealed = 0;
    // Can be made callable by everyone but restricting to onlyRealOwner for extra security
    // batchNumber belongs to [0, TOKEN_LIMIT/REVEAL_BATCH_SIZE]
    // if fee is incorrect chainlink's coordinator will just revert the tx so it's good
    function requestRandomSeed(uint s_fee) public onlyRealOwner returns (bytes32 requestId) {
        require(totalSupply() >= (lastTokenRevealed + REVEAL_BATCH_SIZE), "totalSupply too low");
        // checking LINK balance
        require(IERC20(linkToken).balanceOf(address(this)) >= s_fee, "Not enough LINK to pay fee");
        // requesting randomness
        requestId = requestRandomness(s_keyHash, s_fee);
    }
    function fulfillRandomness(bytes32, uint256 randomness) internal override {
        require(totalSupply() >= (lastTokenRevealed + REVEAL_BATCH_SIZE), "totalSupply too low");
        uint batchNumber = lastTokenRevealed/REVEAL_BATCH_SIZE;
        // not perfectly random since the folding doesn't match bounds perfectly, but difference is small
        batchToSeed[batchNumber] = randomness % (TOKEN_LIMIT - (batchNumber*REVEAL_BATCH_SIZE));
        unchecked {
            lastTokenRevealed += REVEAL_BATCH_SIZE;
        }
    }
    // OPTIMIZATION: No need for numbers to be readable, so this could be optimized
    // but gas cost here doesn't matter so we go for the standard approach
    function tokenURI(uint256 id) public view override returns (string memory) {
        if(!useFancyMath){
            return string(abi.encodePacked(baseURI, id.toString()));
        }
        if(id >= lastTokenRevealed){
            return unrevealedURI;
        } else {
            uint batch = id/REVEAL_BATCH_SIZE;
            return string(abi.encodePacked(baseURI, getShuffledTokenId(id, batch).toString(), ".json"));
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)
pragma solidity ^0.8.0;
/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol
        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }
    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }
    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);
    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);
    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);
    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);
    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);
    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);
    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}
//SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "@openzeppelin/contracts/access/Ownable.sol";
/*
Opensea only allows EOAs to make changes to collections,
which makes it impossible to use multisigs to secure these NFT contracts
since when you want to make changes you need to transfer ownership to an EOA, who can rug.
This contract establishes a second owner that can change the EOA owner,
this way a multisig can give ownership to an EOA and later claim it back.
*/
abstract contract MultisigOwnable is Ownable {
    address public realOwner;
    constructor() {
        realOwner = msg.sender;
    }
    modifier onlyRealOwner() {
        require(realOwner == msg.sender, "MultisigOwnable: caller is not the real owner");
        _;
    }
    function transferRealOwnership(address newRealOwner) public onlyRealOwner {
        realOwner = newRealOwner;
    }
    function transferLowerOwnership(address newOwner) public onlyRealOwner {
        _transferOwnership(newOwner);
    }
}// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./interfaces/LinkTokenInterface.sol";
import "./VRFRequestIDBase.sol";
/** ****************************************************************************
 * @notice Interface for contracts using VRF randomness
 * *****************************************************************************
 * @dev PURPOSE
 *
 * @dev Reggie the Random Oracle (not his real job) wants to provide randomness
 * @dev to Vera the verifier in such a way that Vera can be sure he's not
 * @dev making his output up to suit himself. Reggie provides Vera a public key
 * @dev to which he knows the secret key. Each time Vera provides a seed to
 * @dev Reggie, he gives back a value which is computed completely
 * @dev deterministically from the seed and the secret key.
 *
 * @dev Reggie provides a proof by which Vera can verify that the output was
 * @dev correctly computed once Reggie tells it to her, but without that proof,
 * @dev the output is indistinguishable to her from a uniform random sample
 * @dev from the output space.
 *
 * @dev The purpose of this contract is to make it easy for unrelated contracts
 * @dev to talk to Vera the verifier about the work Reggie is doing, to provide
 * @dev simple access to a verifiable source of randomness.
 * *****************************************************************************
 * @dev USAGE
 *
 * @dev Calling contracts must inherit from VRFConsumerBase, and can
 * @dev initialize VRFConsumerBase's attributes in their constructor as
 * @dev shown:
 *
 * @dev   contract VRFConsumer {
 * @dev     constuctor(<other arguments>, address _vrfCoordinator, address _link)
 * @dev       VRFConsumerBase(_vrfCoordinator, _link) public {
 * @dev         <initialization with other arguments goes here>
 * @dev       }
 * @dev   }
 *
 * @dev The oracle will have given you an ID for the VRF keypair they have
 * @dev committed to (let's call it keyHash), and have told you the minimum LINK
 * @dev price for VRF service. Make sure your contract has sufficient LINK, and
 * @dev call requestRandomness(keyHash, fee, seed), where seed is the input you
 * @dev want to generate randomness from.
 *
 * @dev Once the VRFCoordinator has received and validated the oracle's response
 * @dev to your request, it will call your contract's fulfillRandomness method.
 *
 * @dev The randomness argument to fulfillRandomness is the actual random value
 * @dev generated from your seed.
 *
 * @dev The requestId argument is generated from the keyHash and the seed by
 * @dev makeRequestId(keyHash, seed). If your contract could have concurrent
 * @dev requests open, you can use the requestId to track which seed is
 * @dev associated with which randomness. See VRFRequestIDBase.sol for more
 * @dev details. (See "SECURITY CONSIDERATIONS" for principles to keep in mind,
 * @dev if your contract could have multiple requests in flight simultaneously.)
 *
 * @dev Colliding `requestId`s are cryptographically impossible as long as seeds
 * @dev differ. (Which is critical to making unpredictable randomness! See the
 * @dev next section.)
 *
 * *****************************************************************************
 * @dev SECURITY CONSIDERATIONS
 *
 * @dev A method with the ability to call your fulfillRandomness method directly
 * @dev could spoof a VRF response with any random value, so it's critical that
 * @dev it cannot be directly called by anything other than this base contract
 * @dev (specifically, by the VRFConsumerBase.rawFulfillRandomness method).
 *
 * @dev For your users to trust that your contract's random behavior is free
 * @dev from malicious interference, it's best if you can write it so that all
 * @dev behaviors implied by a VRF response are executed *during* your
 * @dev fulfillRandomness method. If your contract must store the response (or
 * @dev anything derived from it) and use it later, you must ensure that any
 * @dev user-significant behavior which depends on that stored value cannot be
 * @dev manipulated by a subsequent VRF request.
 *
 * @dev Similarly, both miners and the VRF oracle itself have some influence
 * @dev over the order in which VRF responses appear on the blockchain, so if
 * @dev your contract could have multiple VRF requests in flight simultaneously,
 * @dev you must ensure that the order in which the VRF responses arrive cannot
 * @dev be used to manipulate your contract's user-significant behavior.
 *
 * @dev Since the ultimate input to the VRF is mixed with the block hash of the
 * @dev block in which the request is made, user-provided seeds have no impact
 * @dev on its economic security properties. They are only included for API
 * @dev compatability with previous versions of this contract.
 *
 * @dev Since the block hash of the block which contains the requestRandomness
 * @dev call is mixed into the input to the VRF *last*, a sufficiently powerful
 * @dev miner could, in principle, fork the blockchain to evict the block
 * @dev containing the request, forcing the request to be included in a
 * @dev different block with a different hash, and therefore a different input
 * @dev to the VRF. However, such an attack would incur a substantial economic
 * @dev cost. This cost scales with the number of blocks the VRF oracle waits
 * @dev until it calls responds to a request.
 */
abstract contract VRFConsumerBase is VRFRequestIDBase {
  /**
   * @notice fulfillRandomness handles the VRF response. Your contract must
   * @notice implement it. See "SECURITY CONSIDERATIONS" above for important
   * @notice principles to keep in mind when implementing your fulfillRandomness
   * @notice method.
   *
   * @dev VRFConsumerBase expects its subcontracts to have a method with this
   * @dev signature, and will call it once it has verified the proof
   * @dev associated with the randomness. (It is triggered via a call to
   * @dev rawFulfillRandomness, below.)
   *
   * @param requestId The Id initially returned by requestRandomness
   * @param randomness the VRF output
   */
  function fulfillRandomness(bytes32 requestId, uint256 randomness) internal virtual;
  /**
   * @dev In order to keep backwards compatibility we have kept the user
   * seed field around. We remove the use of it because given that the blockhash
   * enters later, it overrides whatever randomness the used seed provides.
   * Given that it adds no security, and can easily lead to misunderstandings,
   * we have removed it from usage and can now provide a simpler API.
   */
  uint256 private constant USER_SEED_PLACEHOLDER = 0;
  /**
   * @notice requestRandomness initiates a request for VRF output given _seed
   *
   * @dev The fulfillRandomness method receives the output, once it's provided
   * @dev by the Oracle, and verified by the vrfCoordinator.
   *
   * @dev The _keyHash must already be registered with the VRFCoordinator, and
   * @dev the _fee must exceed the fee specified during registration of the
   * @dev _keyHash.
   *
   * @dev The _seed parameter is vestigial, and is kept only for API
   * @dev compatibility with older versions. It can't *hurt* to mix in some of
   * @dev your own randomness, here, but it's not necessary because the VRF
   * @dev oracle will mix the hash of the block containing your request into the
   * @dev VRF seed it ultimately uses.
   *
   * @param _keyHash ID of public key against which randomness is generated
   * @param _fee The amount of LINK to send with the request
   *
   * @return requestId unique ID for this request
   *
   * @dev The returned requestId can be used to distinguish responses to
   * @dev concurrent requests. It is passed as the first argument to
   * @dev fulfillRandomness.
   */
  function requestRandomness(bytes32 _keyHash, uint256 _fee) internal returns (bytes32 requestId) {
    LINK.transferAndCall(vrfCoordinator, _fee, abi.encode(_keyHash, USER_SEED_PLACEHOLDER));
    // This is the seed passed to VRFCoordinator. The oracle will mix this with
    // the hash of the block containing this request to obtain the seed/input
    // which is finally passed to the VRF cryptographic machinery.
    uint256 vRFSeed = makeVRFInputSeed(_keyHash, USER_SEED_PLACEHOLDER, address(this), nonces[_keyHash]);
    // nonces[_keyHash] must stay in sync with
    // VRFCoordinator.nonces[_keyHash][this], which was incremented by the above
    // successful LINK.transferAndCall (in VRFCoordinator.randomnessRequest).
    // This provides protection against the user repeating their input seed,
    // which would result in a predictable/duplicate output, if multiple such
    // requests appeared in the same block.
    nonces[_keyHash] = nonces[_keyHash] + 1;
    return makeRequestId(_keyHash, vRFSeed);
  }
  LinkTokenInterface internal immutable LINK;
  address private immutable vrfCoordinator;
  // Nonces for each VRF key from which randomness has been requested.
  //
  // Must stay in sync with VRFCoordinator[_keyHash][this]
  mapping(bytes32 => uint256) /* keyHash */ /* nonce */
    private nonces;
  /**
   * @param _vrfCoordinator address of VRFCoordinator contract
   * @param _link address of LINK token contract
   *
   * @dev https://docs.chain.link/docs/link-token-contracts
   */
  constructor(address _vrfCoordinator, address _link) {
    vrfCoordinator = _vrfCoordinator;
    LINK = LinkTokenInterface(_link);
  }
  // rawFulfillRandomness is called by VRFCoordinator when it receives a valid VRF
  // proof. rawFulfillRandomness then calls fulfillRandomness, after validating
  // the origin of the call
  function rawFulfillRandomness(bytes32 requestId, uint256 randomness) external {
    require(msg.sender == vrfCoordinator, "Only VRFCoordinator can fulfill");
    fulfillRandomness(requestId, randomness);
  }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/cryptography/MerkleProof.sol)
pragma solidity ^0.8.0;
/**
 * @dev These functions deal with verification of Merkle Trees proofs.
 *
 * The proofs can be generated using the JavaScript library
 * https://github.com/miguelmota/merkletreejs[merkletreejs].
 * Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.
 *
 * See `test/utils/cryptography/MerkleProof.test.js` for some examples.
 */
library MerkleProof {
    /**
     * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
     * defined by `root`. For this, a `proof` must be provided, containing
     * sibling hashes on the branch from the leaf to the root of the tree. Each
     * pair of leaves and each pair of pre-images are assumed to be sorted.
     */
    function verify(
        bytes32[] memory proof,
        bytes32 root,
        bytes32 leaf
    ) internal pure returns (bool) {
        return processProof(proof, leaf) == root;
    }
    /**
     * @dev Returns the rebuilt hash obtained by traversing a Merklee tree up
     * from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
     * hash matches the root of the tree. When processing the proof, the pairs
     * of leafs & pre-images are assumed to be sorted.
     *
     * _Available since v4.4._
     */
    function processProof(bytes32[] memory proof, bytes32 leaf) internal pure returns (bytes32) {
        bytes32 computedHash = leaf;
        for (uint256 i = 0; i < proof.length; i++) {
            bytes32 proofElement = proof[i];
            if (computedHash <= proofElement) {
                // Hash(current computed hash + current element of the proof)
                computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
            } else {
                // Hash(current element of the proof + current computed hash)
                computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
            }
        }
        return computedHash;
    }
}
// SPDX-License-Identifier: MIT
// Creator: Chiru Labs
// Fork of ERC721A.sol (it's not the same one as on npm package erc721a because this one has extension methods removed)
pragma solidity ^0.8.4;
import '@openzeppelin/contracts/token/ERC721/IERC721.sol';
import '@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol';
import '@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol';
import '@openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol';
import '@openzeppelin/contracts/utils/Address.sol';
import '@openzeppelin/contracts/utils/Context.sol';
import '@openzeppelin/contracts/utils/Strings.sol';
import '@openzeppelin/contracts/utils/introspection/ERC165.sol';
error ApprovalCallerNotOwnerNorApproved();
error ApprovalQueryForNonexistentToken();
error ApproveToCaller();
error ApprovalToCurrentOwner();
error BalanceQueryForZeroAddress();
error MintedQueryForZeroAddress();
error BurnedQueryForZeroAddress();
error MintToZeroAddress();
error MintZeroQuantity();
error OwnerIndexOutOfBounds();
error OwnerQueryForNonexistentToken();
error TokenIndexOutOfBounds();
error TransferCallerNotOwnerNorApproved();
error TransferFromIncorrectOwner();
error TransferToNonERC721ReceiverImplementer();
error TransferToZeroAddress();
error URIQueryForNonexistentToken();
/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata and Enumerable extension. Built to optimize for lower gas during batch mints.
 *
 * Assumes serials are sequentially minted starting at 0 (e.g. 0, 1, 2, 3..).
 *
 * Assumes that an owner cannot have more than 2**64 - 1 (max value of uint64) of supply.
 *
 * Assumes that the maximum token id cannot exceed 2**256 - 1 (max value of uint256).
 */
contract ERC721A is Context, ERC165, IERC721, IERC721Metadata {
    using Address for address;
    using Strings for uint256;
    // Compiler will pack this into a single 256bit word.
    struct TokenOwnership {
        // The address of the owner.
        address addr;
        // Keeps track of the start time of ownership with minimal overhead for tokenomics.
        uint64 startTimestamp;
        // Whether the token has been burned.
        bool burned;
    }
    // Compiler will pack this into a single 256bit word.
    struct AddressData {
        // Realistically, 2**64-1 is more than enough.
        uint64 balance;
        // Keeps track of mint count with minimal overhead for tokenomics.
        uint64 numberMinted;
        // Keeps track of burn count with minimal overhead for tokenomics.
        uint64 numberBurned;
    }
    // The tokenId of the next token to be minted.
    uint256 internal _currentIndex;
    // The number of tokens burned.
    uint256 internal _burnCounter;
    // Token name
    string private _name;
    // Token symbol
    string private _symbol;
    // Mapping from token ID to ownership details
    // An empty struct value does not necessarily mean the token is unowned. See ownershipOf implementation for details.
    mapping(uint256 => TokenOwnership) internal _ownerships;
    // Mapping owner address to address data
    mapping(address => AddressData) private _addressData;
    // 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;
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }
    /**
     * @dev See {IERC721Enumerable-totalSupply}.
     */
    function totalSupply() public view returns (uint256) {
        // Counter underflow is impossible as _burnCounter cannot be incremented
        // more than _currentIndex times
        unchecked {
            return _currentIndex - _burnCounter;    
        }
    }
    /**
     * @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 override returns (uint256) {
        if (owner == address(0)) revert BalanceQueryForZeroAddress();
        return uint256(_addressData[owner].balance);
    }
    function _numberMinted(address owner) internal view returns (uint256) {
        if (owner == address(0)) revert MintedQueryForZeroAddress();
        return uint256(_addressData[owner].numberMinted);
    }
    function _numberBurned(address owner) internal view returns (uint256) {
        if (owner == address(0)) revert BurnedQueryForZeroAddress();
        return uint256(_addressData[owner].numberBurned);
    }
    /**
     * Gas spent here starts off proportional to the maximum mint batch size.
     * It gradually moves to O(1) as tokens get transferred around in the collection over time.
     */
    function ownershipOf(uint256 tokenId) internal view returns (TokenOwnership memory) {
        uint256 curr = tokenId;
        unchecked {
            if (curr < _currentIndex) {
                TokenOwnership memory ownership = _ownerships[curr];
                if (!ownership.burned) {
                    if (ownership.addr != address(0)) {
                        return ownership;
                    }
                    // Invariant: 
                    // There will always be an ownership that has an address and is not burned 
                    // before an ownership that does not have an address and is not burned.
                    // Hence, curr will not underflow.
                    while (true) {
                        curr--;
                        ownership = _ownerships[curr];
                        if (ownership.addr != address(0)) {
                            return ownership;
                        }
                    }
                }
            }
        }
        revert OwnerQueryForNonexistentToken();
    }
    /**
     * @dev See {IERC721-ownerOf}.
     */
    function ownerOf(uint256 tokenId) public view override returns (address) {
        return ownershipOf(tokenId).addr;
    }
    /**
     * @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) {
        if (!_exists(tokenId)) revert URIQueryForNonexistentToken();
        string memory baseURI = _baseURI();
        return bytes(baseURI).length != 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : '';
    }
    /**
     * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
     * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
     * by default, can be overriden in child contracts.
     */
    function _baseURI() internal view virtual returns (string memory) {
        return '';
    }
    /**
     * @dev See {IERC721-approve}.
     */
    function approve(address to, uint256 tokenId) public override {
        address owner = ERC721A.ownerOf(tokenId);
        if (to == owner) revert ApprovalToCurrentOwner();
        if (_msgSender() != owner && !isApprovedForAll(owner, _msgSender())) {
            revert ApprovalCallerNotOwnerNorApproved();
        }
        _approve(to, tokenId, owner);
    }
    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId) public view override returns (address) {
        if (!_exists(tokenId)) revert ApprovalQueryForNonexistentToken();
        return _tokenApprovals[tokenId];
    }
    /**
     * @dev See {IERC721-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public override {
        if (operator == _msgSender()) revert ApproveToCaller();
        _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 {
        _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 {
        _transfer(from, to, tokenId);
        if (!_checkOnERC721Received(from, to, tokenId, _data)) {
            revert TransferToNonERC721ReceiverImplementer();
        }
    }
    /**
     * @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`),
     */
    function _exists(uint256 tokenId) internal view returns (bool) {
        return tokenId < _currentIndex && !_ownerships[tokenId].burned;
    }
    function _safeMint(address to, uint256 quantity) internal {
        _safeMint(to, quantity, '');
    }
    /**
     * @dev Safely mints `quantity` tokens and transfers them to `to`.
     *
     * Requirements:
     *
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called for each safe transfer.
     * - `quantity` must be greater than 0.
     *
     * Emits a {Transfer} event.
     */
    function _safeMint(
        address to,
        uint256 quantity,
        bytes memory _data
    ) internal {
        _mint(to, quantity, _data, true);
    }
    /**
     * @dev Mints `quantity` tokens and transfers them to `to`.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `quantity` must be greater than 0.
     *
     * Emits a {Transfer} event.
     */
    function _mint(
        address to,
        uint256 quantity,
        bytes memory _data,
        bool safe
    ) internal {
        uint256 startTokenId = _currentIndex;
        if (to == address(0)) revert MintToZeroAddress();
        if (quantity == 0) revert MintZeroQuantity();
        _beforeTokenTransfers(address(0), to, startTokenId, quantity);
        // Overflows are incredibly unrealistic.
        // balance or numberMinted overflow if current value of either + quantity > 1.8e19 (2**64) - 1
        // updatedIndex overflows if _currentIndex + quantity > 1.2e77 (2**256) - 1
        unchecked {
            _addressData[to].balance += uint64(quantity);
            _addressData[to].numberMinted += uint64(quantity);
            _ownerships[startTokenId].addr = to;
            _ownerships[startTokenId].startTimestamp = uint64(block.timestamp);
            uint256 updatedIndex = startTokenId;
            for (uint256 i; i < quantity; i++) {
                emit Transfer(address(0), to, updatedIndex);
                if (safe && !_checkOnERC721Received(address(0), to, updatedIndex, _data)) {
                    revert TransferToNonERC721ReceiverImplementer();
                }
                updatedIndex++;
            }
            _currentIndex = updatedIndex;
        }
        _afterTokenTransfers(address(0), to, startTokenId, quantity);
    }
    /**
     * @dev Transfers `tokenId` from `from` to `to`.
     *
     * 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
    ) private {
        TokenOwnership memory prevOwnership = ownershipOf(tokenId);
        bool isApprovedOrOwner = (_msgSender() == prevOwnership.addr ||
            isApprovedForAll(prevOwnership.addr, _msgSender()) ||
            getApproved(tokenId) == _msgSender());
        if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
        if (prevOwnership.addr != from) revert TransferFromIncorrectOwner();
        if (to == address(0)) revert TransferToZeroAddress();
        _beforeTokenTransfers(from, to, tokenId, 1);
        // Clear approvals from the previous owner
        _approve(address(0), tokenId, prevOwnership.addr);
        // Underflow of the sender's balance is impossible because we check for
        // ownership above and the recipient's balance can't realistically overflow.
        // Counter overflow is incredibly unrealistic as tokenId would have to be 2**256.
        unchecked {
            _addressData[from].balance -= 1;
            _addressData[to].balance += 1;
            _ownerships[tokenId].addr = to;
            _ownerships[tokenId].startTimestamp = uint64(block.timestamp);
            // If the ownership slot of tokenId+1 is not explicitly set, that means the transfer initiator owns it.
            // Set the slot of tokenId+1 explicitly in storage to maintain correctness for ownerOf(tokenId+1) calls.
            uint256 nextTokenId = tokenId + 1;
            if (_ownerships[nextTokenId].addr == address(0)) {
                // This will suffice for checking _exists(nextTokenId),
                // as a burned slot cannot contain the zero address.
                if (nextTokenId < _currentIndex) {
                    _ownerships[nextTokenId].addr = prevOwnership.addr;
                    _ownerships[nextTokenId].startTimestamp = prevOwnership.startTimestamp;
                }
            }
        }
        emit Transfer(from, to, tokenId);
        _afterTokenTransfers(from, to, tokenId, 1);
    }
    /**
     * @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 {
        TokenOwnership memory prevOwnership = ownershipOf(tokenId);
        _beforeTokenTransfers(prevOwnership.addr, address(0), tokenId, 1);
        // Clear approvals from the previous owner
        _approve(address(0), tokenId, prevOwnership.addr);
        // Underflow of the sender's balance is impossible because we check for
        // ownership above and the recipient's balance can't realistically overflow.
        // Counter overflow is incredibly unrealistic as tokenId would have to be 2**256.
        unchecked {
            _addressData[prevOwnership.addr].balance -= 1;
            _addressData[prevOwnership.addr].numberBurned += 1;
            // Keep track of who burned the token, and the timestamp of burning.
            _ownerships[tokenId].addr = prevOwnership.addr;
            _ownerships[tokenId].startTimestamp = uint64(block.timestamp);
            _ownerships[tokenId].burned = true;
            // If the ownership slot of tokenId+1 is not explicitly set, that means the burn initiator owns it.
            // Set the slot of tokenId+1 explicitly in storage to maintain correctness for ownerOf(tokenId+1) calls.
            uint256 nextTokenId = tokenId + 1;
            if (_ownerships[nextTokenId].addr == address(0)) {
                // This will suffice for checking _exists(nextTokenId),
                // as a burned slot cannot contain the zero address.
                if (nextTokenId < _currentIndex) {
                    _ownerships[nextTokenId].addr = prevOwnership.addr;
                    _ownerships[nextTokenId].startTimestamp = prevOwnership.startTimestamp;
                }
            }
        }
        emit Transfer(prevOwnership.addr, address(0), tokenId);
        _afterTokenTransfers(prevOwnership.addr, address(0), tokenId, 1);
        // Overflow not possible, as _burnCounter cannot be exceed _currentIndex times.
        unchecked { 
            _burnCounter++;
        }
    }
    /**
     * @dev Approve `to` to operate on `tokenId`
     *
     * Emits a {Approval} event.
     */
    function _approve(
        address to,
        uint256 tokenId,
        address owner
    ) private {
        _tokenApprovals[tokenId] = to;
        emit Approval(owner, 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 TransferToNonERC721ReceiverImplementer();
                } else {
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            return true;
        }
    }
    /**
     * @dev Hook that is called before a set of serially-ordered token ids are about to be transferred. This includes minting.
     * And also called before burning one token.
     *
     * startTokenId - the first token id to be transferred
     * quantity - the amount to be transferred
     *
     * 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, `tokenId` will be burned by `from`.
     * - `from` and `to` are never both zero.
     */
    function _beforeTokenTransfers(
        address from,
        address to,
        uint256 startTokenId,
        uint256 quantity
    ) internal virtual {}
    /**
     * @dev Hook that is called after a set of serially-ordered token ids have been transferred. This includes
     * minting.
     * And also called after one token has been burned.
     *
     * startTokenId - the first token id to be transferred
     * quantity - the amount to be transferred
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, `from`'s `tokenId` has been
     * transferred to `to`.
     * - When `from` is zero, `tokenId` has been minted for `to`.
     * - When `to` is zero, `tokenId` has been burned by `from`.
     * - `from` and `to` are never both zero.
     */
    function _afterTokenTransfers(
        address from,
        address to,
        uint256 startTokenId,
        uint256 quantity
    ) internal virtual {}
}//SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/*
  See ../../randomness.md
*/
abstract contract BatchReveal {
    uint constant public TOKEN_LIMIT = 20e3;
    uint constant public REVEAL_BATCH_SIZE = 1e3;
    mapping(uint => uint) public batchToSeed;
    struct Range{
        int128 start;
        int128 end;
    }
    // Forked from openzeppelin
    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(int128 a, int128 b) internal pure returns (int128) {
        return a < b ? a : b;
    }
    uint constant RANGE_LENGTH = (TOKEN_LIMIT/REVEAL_BATCH_SIZE)*2;
    int128 constant intTOKEN_LIMIT = int128(int(TOKEN_LIMIT));
    // ranges include the start but not the end [start, end)
    function addRange(Range[RANGE_LENGTH] memory ranges, int128 start, int128 end, uint lastIndex) pure private returns (uint) {
        uint positionToAssume = lastIndex;
        for(uint j=0; j<lastIndex; j++){
            int128 rangeStart = ranges[j].start;
            int128 rangeEnd = ranges[j].end;
            if(start < rangeStart && positionToAssume == lastIndex){
                positionToAssume = j;
            }
            if(
                (start < rangeStart && end > rangeStart) ||
                (rangeStart <= start &&  end <= rangeEnd) ||
                (start < rangeEnd && end > rangeEnd)
            ){
                int128 length = end-start;
                start = min(start, rangeStart);
                end = start + length + (rangeEnd-rangeStart);
                ranges[j] = Range(-1,-1); // Delete
            }
        }
        for(uint pos = lastIndex; pos > positionToAssume; pos--){
            ranges[pos] = ranges[pos-1];
        }
        ranges[positionToAssume] = Range(start, min(end, intTOKEN_LIMIT));
        lastIndex++;
        if(end > intTOKEN_LIMIT){
            addRange(ranges, 0, end - intTOKEN_LIMIT, lastIndex);
            lastIndex++;
        }
        return lastIndex;
    }
    function buildJumps(uint lastBatch) view private returns (Range[RANGE_LENGTH] memory) {
        Range[RANGE_LENGTH] memory ranges;
        uint lastIndex = 0;
        for(uint i=0; i<lastBatch; i++){
            int128 start = int128(int(getFreeTokenId(batchToSeed[i], ranges)));
            int128 end = start + int128(int(REVEAL_BATCH_SIZE));
            lastIndex = addRange(ranges, start, end, lastIndex);
        }
        return ranges;
    }
    function getShuffledTokenId(uint startId, uint batch) view internal returns (uint) {
        Range[RANGE_LENGTH] memory ranges = buildJumps(batch);
        uint positionsToMove = (startId % REVEAL_BATCH_SIZE) + batchToSeed[batch];
        return getFreeTokenId(positionsToMove, ranges);
    }
    function getFreeTokenId(uint positionsToMoveStart, Range[RANGE_LENGTH] memory ranges) pure private returns (uint) {
        int128 positionsToMove = int128(int(positionsToMoveStart));
        int128 id = 0;
        for(uint round = 0; round<2; round++){
            for(uint i=0; i<RANGE_LENGTH; i++){
                int128 start = ranges[i].start;
                int128 end = ranges[i].end;
                if(id < start){
                    int128 finalId = id + positionsToMove;
                    if(finalId < start){
                        return uint(uint128(finalId));
                    } else {
                        positionsToMove -= start - id;
                        id = end;
                    }
                } else if(id < end){
                    id = end;
                }
            }
            if((id + positionsToMove) >= intTOKEN_LIMIT){
                positionsToMove -= intTOKEN_LIMIT - id;
                id = 0;
            }
        }
        return uint(uint128(id + positionsToMove));
    }
}// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }
    /**
     * @dev 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 {
        _transferOwnership(address(0));
    }
    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }
    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
pragma solidity ^0.8.0;
/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }
    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
interface LinkTokenInterface {
  function allowance(address owner, address spender) external view returns (uint256 remaining);
  function approve(address spender, uint256 value) external returns (bool success);
  function balanceOf(address owner) external view returns (uint256 balance);
  function decimals() external view returns (uint8 decimalPlaces);
  function decreaseApproval(address spender, uint256 addedValue) external returns (bool success);
  function increaseApproval(address spender, uint256 subtractedValue) external;
  function name() external view returns (string memory tokenName);
  function symbol() external view returns (string memory tokenSymbol);
  function totalSupply() external view returns (uint256 totalTokensIssued);
  function transfer(address to, uint256 value) external returns (bool success);
  function transferAndCall(
    address to,
    uint256 value,
    bytes calldata data
  ) external returns (bool success);
  function transferFrom(
    address from,
    address to,
    uint256 value
  ) external returns (bool success);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract VRFRequestIDBase {
  /**
   * @notice returns the seed which is actually input to the VRF coordinator
   *
   * @dev To prevent repetition of VRF output due to repetition of the
   * @dev user-supplied seed, that seed is combined in a hash with the
   * @dev user-specific nonce, and the address of the consuming contract. The
   * @dev risk of repetition is mostly mitigated by inclusion of a blockhash in
   * @dev the final seed, but the nonce does protect against repetition in
   * @dev requests which are included in a single block.
   *
   * @param _userSeed VRF seed input provided by user
   * @param _requester Address of the requesting contract
   * @param _nonce User-specific nonce at the time of the request
   */
  function makeVRFInputSeed(
    bytes32 _keyHash,
    uint256 _userSeed,
    address _requester,
    uint256 _nonce
  ) internal pure returns (uint256) {
    return uint256(keccak256(abi.encode(_keyHash, _userSeed, _requester, _nonce)));
  }
  /**
   * @notice Returns the id for this request
   * @param _keyHash The serviceAgreement ID to be used for this request
   * @param _vRFInputSeed The seed to be passed directly to the VRF
   * @return The id for this request
   *
   * @dev Note that _vRFInputSeed is not the seed passed by the consuming
   * @dev contract, but the one generated by makeVRFInputSeed
   */
  function makeRequestId(bytes32 _keyHash, uint256 _vRFInputSeed) internal pure returns (bytes32) {
    return keccak256(abi.encodePacked(_keyHash, _vRFInputSeed));
  }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)
pragma solidity ^0.8.0;
import "../../utils/introspection/IERC165.sol";
/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);
    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);
    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, 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;
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (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);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)
pragma solidity ^0.8.0;
import "../IERC721.sol";
/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Metadata is IERC721 {
    /**
     * @dev Returns the token collection name.
     */
    function name() external view returns (string memory);
    /**
     * @dev Returns the token collection symbol.
     */
    function symbol() external view returns (string memory);
    /**
     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
     */
    function tokenURI(uint256 tokenId) external view returns (string memory);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Enumerable.sol)
pragma solidity ^0.8.0;
import "../IERC721.sol";
/**
 * @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);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (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;
        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");
        (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");
        (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");
        (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");
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // 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
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)
pragma solidity ^0.8.0;
import "./IERC165.sol";
/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)
pragma solidity ^0.8.0;
/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

pragma solidity ^0.4.13;

contract Ownable {
  address public owner;


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


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  constructor() public {
    owner = msg.sender;
  }

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

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) public onlyOwner {
    require(newOwner != address(0));
    emit OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

  /**
   * @dev Allows the current owner to relinquish control of the contract.
   */
  function renounceOwnership() public onlyOwner {
    emit OwnershipRenounced(owner);
    owner = address(0);
  }
}

contract ERC20Basic {
  function totalSupply() public view returns (uint256);
  function balanceOf(address who) public view returns (uint256);
  function transfer(address to, uint256 value) public returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
}

contract ERC20 is ERC20Basic {
  function allowance(address owner, address spender)
    public view returns (uint256);

  function transferFrom(address from, address to, uint256 value)
    public returns (bool);

  function approve(address spender, uint256 value) public returns (bool);
  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}

contract TokenRecipient {
    event ReceivedEther(address indexed sender, uint amount);
    event ReceivedTokens(address indexed from, uint256 value, address indexed token, bytes extraData);

    /**
     * @dev Receive tokens and generate a log event
     * @param from Address from which to transfer tokens
     * @param value Amount of tokens to transfer
     * @param token Address of token
     * @param extraData Additional data to log
     */
    function receiveApproval(address from, uint256 value, address token, bytes extraData) public {
        ERC20 t = ERC20(token);
        require(t.transferFrom(from, this, value));
        emit ReceivedTokens(from, value, token, extraData);
    }

    /**
     * @dev Receive Ether and generate a log event
     */
    function () payable public {
        emit ReceivedEther(msg.sender, msg.value);
    }
}

contract ProxyRegistry is Ownable {

    /* DelegateProxy implementation contract. Must be initialized. */
    address public delegateProxyImplementation;

    /* Authenticated proxies by user. */
    mapping(address => OwnableDelegateProxy) public proxies;

    /* Contracts pending access. */
    mapping(address => uint) public pending;

    /* Contracts allowed to call those proxies. */
    mapping(address => bool) public contracts;

    /* Delay period for adding an authenticated contract.
       This mitigates a particular class of potential attack on the Wyvern DAO (which owns this registry) - if at any point the value of assets held by proxy contracts exceeded the value of half the WYV supply (votes in the DAO),
       a malicious but rational attacker could buy half the Wyvern and grant themselves access to all the proxy contracts. A delay period renders this attack nonthreatening - given two weeks, if that happened, users would have
       plenty of time to notice and transfer their assets.
    */
    uint public DELAY_PERIOD = 2 weeks;

    /**
     * Start the process to enable access for specified contract. Subject to delay period.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address to which to grant permissions
     */
    function startGrantAuthentication (address addr)
        public
        onlyOwner
    {
        require(!contracts[addr] && pending[addr] == 0);
        pending[addr] = now;
    }

    /**
     * End the process to nable access for specified contract after delay period has passed.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address to which to grant permissions
     */
    function endGrantAuthentication (address addr)
        public
        onlyOwner
    {
        require(!contracts[addr] && pending[addr] != 0 && ((pending[addr] + DELAY_PERIOD) < now));
        pending[addr] = 0;
        contracts[addr] = true;
    }

    /**
     * Revoke access for specified contract. Can be done instantly.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address of which to revoke permissions
     */    
    function revokeAuthentication (address addr)
        public
        onlyOwner
    {
        contracts[addr] = false;
    }

    /**
     * Register a proxy contract with this registry
     *
     * @dev Must be called by the user which the proxy is for, creates a new AuthenticatedProxy
     * @return New AuthenticatedProxy contract
     */
    function registerProxy()
        public
        returns (OwnableDelegateProxy proxy)
    {
        require(proxies[msg.sender] == address(0));
        proxy = new OwnableDelegateProxy(msg.sender, delegateProxyImplementation, abi.encodeWithSignature("initialize(address,address)", msg.sender, address(this)));
        proxies[msg.sender] = proxy;
        return proxy;
    }

}

contract WyvernProxyRegistry is ProxyRegistry {

    string public constant name = "Project Wyvern Proxy Registry";

    /* Whether the initial auth address has been set. */
    bool public initialAddressSet = false;

    constructor ()
        public
    {
        delegateProxyImplementation = new AuthenticatedProxy();
    }

    /** 
     * Grant authentication to the initial Exchange protocol contract
     *
     * @dev No delay, can only be called once - after that the standard registry process with a delay must be used
     * @param authAddress Address of the contract to grant authentication
     */
    function grantInitialAuthentication (address authAddress)
        onlyOwner
        public
    {
        require(!initialAddressSet);
        initialAddressSet = true;
        contracts[authAddress] = true;
    }

}

contract OwnedUpgradeabilityStorage {

  // Current implementation
  address internal _implementation;

  // Owner of the contract
  address private _upgradeabilityOwner;

  /**
   * @dev Tells the address of the owner
   * @return the address of the owner
   */
  function upgradeabilityOwner() public view returns (address) {
    return _upgradeabilityOwner;
  }

  /**
   * @dev Sets the address of the owner
   */
  function setUpgradeabilityOwner(address newUpgradeabilityOwner) internal {
    _upgradeabilityOwner = newUpgradeabilityOwner;
  }

  /**
  * @dev Tells the address of the current implementation
  * @return address of the current implementation
  */
  function implementation() public view returns (address) {
    return _implementation;
  }

  /**
  * @dev Tells the proxy type (EIP 897)
  * @return Proxy type, 2 for forwarding proxy
  */
  function proxyType() public pure returns (uint256 proxyTypeId) {
    return 2;
  }
}

contract AuthenticatedProxy is TokenRecipient, OwnedUpgradeabilityStorage {

    /* Whether initialized. */
    bool initialized = false;

    /* Address which owns this proxy. */
    address public user;

    /* Associated registry with contract authentication information. */
    ProxyRegistry public registry;

    /* Whether access has been revoked. */
    bool public revoked;

    /* Delegate call could be used to atomically transfer multiple assets owned by the proxy contract with one order. */
    enum HowToCall { Call, DelegateCall }

    /* Event fired when the proxy access is revoked or unrevoked. */
    event Revoked(bool revoked);

    /**
     * Initialize an AuthenticatedProxy
     *
     * @param addrUser Address of user on whose behalf this proxy will act
     * @param addrRegistry Address of ProxyRegistry contract which will manage this proxy
     */
    function initialize (address addrUser, ProxyRegistry addrRegistry)
        public
    {
        require(!initialized);
        initialized = true;
        user = addrUser;
        registry = addrRegistry;
    }

    /**
     * Set the revoked flag (allows a user to revoke ProxyRegistry access)
     *
     * @dev Can be called by the user only
     * @param revoke Whether or not to revoke access
     */
    function setRevoke(bool revoke)
        public
    {
        require(msg.sender == user);
        revoked = revoke;
        emit Revoked(revoke);
    }

    /**
     * Execute a message call from the proxy contract
     *
     * @dev Can be called by the user, or by a contract authorized by the registry as long as the user has not revoked access
     * @param dest Address to which the call will be sent
     * @param howToCall Which kind of call to make
     * @param calldata Calldata to send
     * @return Result of the call (success or failure)
     */
    function proxy(address dest, HowToCall howToCall, bytes calldata)
        public
        returns (bool result)
    {
        require(msg.sender == user || (!revoked && registry.contracts(msg.sender)));
        if (howToCall == HowToCall.Call) {
            result = dest.call(calldata);
        } else if (howToCall == HowToCall.DelegateCall) {
            result = dest.delegatecall(calldata);
        }
        return result;
    }

    /**
     * Execute a message call and assert success
     * 
     * @dev Same functionality as `proxy`, just asserts the return value
     * @param dest Address to which the call will be sent
     * @param howToCall What kind of call to make
     * @param calldata Calldata to send
     */
    function proxyAssert(address dest, HowToCall howToCall, bytes calldata)
        public
    {
        require(proxy(dest, howToCall, calldata));
    }

}

contract Proxy {

  /**
  * @dev Tells the address of the implementation where every call will be delegated.
  * @return address of the implementation to which it will be delegated
  */
  function implementation() public view returns (address);

  /**
  * @dev Tells the type of proxy (EIP 897)
  * @return Type of proxy, 2 for upgradeable proxy
  */
  function proxyType() public pure returns (uint256 proxyTypeId);

  /**
  * @dev Fallback function allowing to perform a delegatecall to the given implementation.
  * This function will return whatever the implementation call returns
  */
  function () payable public {
    address _impl = implementation();
    require(_impl != address(0));

    assembly {
      let ptr := mload(0x40)
      calldatacopy(ptr, 0, calldatasize)
      let result := delegatecall(gas, _impl, ptr, calldatasize, 0, 0)
      let size := returndatasize
      returndatacopy(ptr, 0, size)

      switch result
      case 0 { revert(ptr, size) }
      default { return(ptr, size) }
    }
  }
}

contract OwnedUpgradeabilityProxy is Proxy, OwnedUpgradeabilityStorage {
  /**
  * @dev Event to show ownership has been transferred
  * @param previousOwner representing the address of the previous owner
  * @param newOwner representing the address of the new owner
  */
  event ProxyOwnershipTransferred(address previousOwner, address newOwner);

  /**
  * @dev This event will be emitted every time the implementation gets upgraded
  * @param implementation representing the address of the upgraded implementation
  */
  event Upgraded(address indexed implementation);

  /**
  * @dev Upgrades the implementation address
  * @param implementation representing the address of the new implementation to be set
  */
  function _upgradeTo(address implementation) internal {
    require(_implementation != implementation);
    _implementation = implementation;
    emit Upgraded(implementation);
  }

  /**
  * @dev Throws if called by any account other than the owner.
  */
  modifier onlyProxyOwner() {
    require(msg.sender == proxyOwner());
    _;
  }

  /**
   * @dev Tells the address of the proxy owner
   * @return the address of the proxy owner
   */
  function proxyOwner() public view returns (address) {
    return upgradeabilityOwner();
  }

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferProxyOwnership(address newOwner) public onlyProxyOwner {
    require(newOwner != address(0));
    emit ProxyOwnershipTransferred(proxyOwner(), newOwner);
    setUpgradeabilityOwner(newOwner);
  }

  /**
   * @dev Allows the upgradeability owner to upgrade the current implementation of the proxy.
   * @param implementation representing the address of the new implementation to be set.
   */
  function upgradeTo(address implementation) public onlyProxyOwner {
    _upgradeTo(implementation);
  }

  /**
   * @dev Allows the upgradeability owner to upgrade the current implementation of the proxy
   * and delegatecall the new implementation for initialization.
   * @param implementation representing the address of the new implementation to be set.
   * @param data represents the msg.data to bet sent in the low level call. This parameter may include the function
   * signature of the implementation to be called with the needed payload
   */
  function upgradeToAndCall(address implementation, bytes data) payable public onlyProxyOwner {
    upgradeTo(implementation);
    require(address(this).delegatecall(data));
  }
}

contract OwnableDelegateProxy is OwnedUpgradeabilityProxy {

    constructor(address owner, address initialImplementation, bytes calldata)
        public
    {
        setUpgradeabilityOwner(owner);
        _upgradeTo(initialImplementation);
        require(initialImplementation.delegatecall(calldata));
    }

}

contract OwnedUpgradeabilityStorage {

  // Current implementation
  address internal _implementation;

  // Owner of the contract
  address private _upgradeabilityOwner;

  /**
   * @dev Tells the address of the owner
   * @return the address of the owner
   */
  function upgradeabilityOwner() public view returns (address) {
    return _upgradeabilityOwner;
  }

  /**
   * @dev Sets the address of the owner
   */
  function setUpgradeabilityOwner(address newUpgradeabilityOwner) internal {
    _upgradeabilityOwner = newUpgradeabilityOwner;
  }

  /**
  * @dev Tells the address of the current implementation
  * @return address of the current implementation
  */
  function implementation() public view returns (address) {
    return _implementation;
  }

  /**
  * @dev Tells the proxy type (EIP 897)
  * @return Proxy type, 2 for forwarding proxy
  */
  function proxyType() public pure returns (uint256 proxyTypeId) {
    return 2;
  }
}



contract Proxy {

  /**
  * @dev Tells the address of the implementation where every call will be delegated.
  * @return address of the implementation to which it will be delegated
  */
  function implementation() public view returns (address);

  /**
  * @dev Tells the type of proxy (EIP 897)
  * @return Type of proxy, 2 for upgradeable proxy
  */
  function proxyType() public pure returns (uint256 proxyTypeId);

  /**
  * @dev Fallback function allowing to perform a delegatecall to the given implementation.
  * This function will return whatever the implementation call returns
  */
  function () payable public {
    address _impl = implementation();
    require(_impl != address(0));

    assembly {
      let ptr := mload(0x40)
      calldatacopy(ptr, 0, calldatasize)
      let result := delegatecall(gas, _impl, ptr, calldatasize, 0, 0)
      let size := returndatasize
      returndatacopy(ptr, 0, size)

      switch result
      case 0 { revert(ptr, size) }
      default { return(ptr, size) }
    }
  }
}

contract OwnedUpgradeabilityProxy is Proxy, OwnedUpgradeabilityStorage {
  /**
  * @dev Event to show ownership has been transferred
  * @param previousOwner representing the address of the previous owner
  * @param newOwner representing the address of the new owner
  */
  event ProxyOwnershipTransferred(address previousOwner, address newOwner);

  /**
  * @dev This event will be emitted every time the implementation gets upgraded
  * @param implementation representing the address of the upgraded implementation
  */
  event Upgraded(address indexed implementation);

  /**
  * @dev Upgrades the implementation address
  * @param implementation representing the address of the new implementation to be set
  */
  function _upgradeTo(address implementation) internal {
    require(_implementation != implementation);
    _implementation = implementation;
    emit Upgraded(implementation);
  }

  /**
  * @dev Throws if called by any account other than the owner.
  */
  modifier onlyProxyOwner() {
    require(msg.sender == proxyOwner());
    _;
  }

  /**
   * @dev Tells the address of the proxy owner
   * @return the address of the proxy owner
   */
  function proxyOwner() public view returns (address) {
    return upgradeabilityOwner();
  }

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferProxyOwnership(address newOwner) public onlyProxyOwner {
    require(newOwner != address(0));
    emit ProxyOwnershipTransferred(proxyOwner(), newOwner);
    setUpgradeabilityOwner(newOwner);
  }

  /**
   * @dev Allows the upgradeability owner to upgrade the current implementation of the proxy.
   * @param implementation representing the address of the new implementation to be set.
   */
  function upgradeTo(address implementation) public onlyProxyOwner {
    _upgradeTo(implementation);
  }

  /**
   * @dev Allows the upgradeability owner to upgrade the current implementation of the proxy
   * and delegatecall the new implementation for initialization.
   * @param implementation representing the address of the new implementation to be set.
   * @param data represents the msg.data to bet sent in the low level call. This parameter may include the function
   * signature of the implementation to be called with the needed payload
   */
  function upgradeToAndCall(address implementation, bytes data) payable public onlyProxyOwner {
    upgradeTo(implementation);
    require(address(this).delegatecall(data));
  }
}


contract OwnableDelegateProxy is OwnedUpgradeabilityProxy {

    constructor(address owner, address initialImplementation, bytes calldata)
        public
    {
        setUpgradeabilityOwner(owner);
        _upgradeTo(initialImplementation);
        require(initialImplementation.delegatecall(calldata));
    }

}

pragma solidity ^0.4.13;

contract Ownable {
  address public owner;


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


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  constructor() public {
    owner = msg.sender;
  }

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

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) public onlyOwner {
    require(newOwner != address(0));
    emit OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

  /**
   * @dev Allows the current owner to relinquish control of the contract.
   */
  function renounceOwnership() public onlyOwner {
    emit OwnershipRenounced(owner);
    owner = address(0);
  }
}

contract ERC20Basic {
  function totalSupply() public view returns (uint256);
  function balanceOf(address who) public view returns (uint256);
  function transfer(address to, uint256 value) public returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
}

contract ERC20 is ERC20Basic {
  function allowance(address owner, address spender)
    public view returns (uint256);

  function transferFrom(address from, address to, uint256 value)
    public returns (bool);

  function approve(address spender, uint256 value) public returns (bool);
  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}

contract ProxyRegistry is Ownable {

    /* DelegateProxy implementation contract. Must be initialized. */
    address public delegateProxyImplementation;

    /* Authenticated proxies by user. */
    mapping(address => OwnableDelegateProxy) public proxies;

    /* Contracts pending access. */
    mapping(address => uint) public pending;

    /* Contracts allowed to call those proxies. */
    mapping(address => bool) public contracts;

    /* Delay period for adding an authenticated contract.
       This mitigates a particular class of potential attack on the Wyvern DAO (which owns this registry) - if at any point the value of assets held by proxy contracts exceeded the value of half the WYV supply (votes in the DAO),
       a malicious but rational attacker could buy half the Wyvern and grant themselves access to all the proxy contracts. A delay period renders this attack nonthreatening - given two weeks, if that happened, users would have
       plenty of time to notice and transfer their assets.
    */
    uint public DELAY_PERIOD = 2 weeks;

    /**
     * Start the process to enable access for specified contract. Subject to delay period.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address to which to grant permissions
     */
    function startGrantAuthentication (address addr)
        public
        onlyOwner
    {
        require(!contracts[addr] && pending[addr] == 0);
        pending[addr] = now;
    }

    /**
     * End the process to nable access for specified contract after delay period has passed.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address to which to grant permissions
     */
    function endGrantAuthentication (address addr)
        public
        onlyOwner
    {
        require(!contracts[addr] && pending[addr] != 0 && ((pending[addr] + DELAY_PERIOD) < now));
        pending[addr] = 0;
        contracts[addr] = true;
    }

    /**
     * Revoke access for specified contract. Can be done instantly.
     *
     * @dev ProxyRegistry owner only
     * @param addr Address of which to revoke permissions
     */    
    function revokeAuthentication (address addr)
        public
        onlyOwner
    {
        contracts[addr] = false;
    }

    /**
     * Register a proxy contract with this registry
     *
     * @dev Must be called by the user which the proxy is for, creates a new AuthenticatedProxy
     * @return New AuthenticatedProxy contract
     */
    function registerProxy()
        public
        returns (OwnableDelegateProxy proxy)
    {
        require(proxies[msg.sender] == address(0));
        proxy = new OwnableDelegateProxy(msg.sender, delegateProxyImplementation, abi.encodeWithSignature("initialize(address,address)", msg.sender, address(this)));
        proxies[msg.sender] = proxy;
        return proxy;
    }

}

contract TokenRecipient {
    event ReceivedEther(address indexed sender, uint amount);
    event ReceivedTokens(address indexed from, uint256 value, address indexed token, bytes extraData);

    /**
     * @dev Receive tokens and generate a log event
     * @param from Address from which to transfer tokens
     * @param value Amount of tokens to transfer
     * @param token Address of token
     * @param extraData Additional data to log
     */
    function receiveApproval(address from, uint256 value, address token, bytes extraData) public {
        ERC20 t = ERC20(token);
        require(t.transferFrom(from, this, value));
        emit ReceivedTokens(from, value, token, extraData);
    }

    /**
     * @dev Receive Ether and generate a log event
     */
    function () payable public {
        emit ReceivedEther(msg.sender, msg.value);
    }
}

contract OwnedUpgradeabilityStorage {

  // Current implementation
  address internal _implementation;

  // Owner of the contract
  address private _upgradeabilityOwner;

  /**
   * @dev Tells the address of the owner
   * @return the address of the owner
   */
  function upgradeabilityOwner() public view returns (address) {
    return _upgradeabilityOwner;
  }

  /**
   * @dev Sets the address of the owner
   */
  function setUpgradeabilityOwner(address newUpgradeabilityOwner) internal {
    _upgradeabilityOwner = newUpgradeabilityOwner;
  }

  /**
  * @dev Tells the address of the current implementation
  * @return address of the current implementation
  */
  function implementation() public view returns (address) {
    return _implementation;
  }

  /**
  * @dev Tells the proxy type (EIP 897)
  * @return Proxy type, 2 for forwarding proxy
  */
  function proxyType() public pure returns (uint256 proxyTypeId) {
    return 2;
  }
}

contract AuthenticatedProxy is TokenRecipient, OwnedUpgradeabilityStorage {

    /* Whether initialized. */
    bool initialized = false;

    /* Address which owns this proxy. */
    address public user;

    /* Associated registry with contract authentication information. */
    ProxyRegistry public registry;

    /* Whether access has been revoked. */
    bool public revoked;

    /* Delegate call could be used to atomically transfer multiple assets owned by the proxy contract with one order. */
    enum HowToCall { Call, DelegateCall }

    /* Event fired when the proxy access is revoked or unrevoked. */
    event Revoked(bool revoked);

    /**
     * Initialize an AuthenticatedProxy
     *
     * @param addrUser Address of user on whose behalf this proxy will act
     * @param addrRegistry Address of ProxyRegistry contract which will manage this proxy
     */
    function initialize (address addrUser, ProxyRegistry addrRegistry)
        public
    {
        require(!initialized);
        initialized = true;
        user = addrUser;
        registry = addrRegistry;
    }

    /**
     * Set the revoked flag (allows a user to revoke ProxyRegistry access)
     *
     * @dev Can be called by the user only
     * @param revoke Whether or not to revoke access
     */
    function setRevoke(bool revoke)
        public
    {
        require(msg.sender == user);
        revoked = revoke;
        emit Revoked(revoke);
    }

    /**
     * Execute a message call from the proxy contract
     *
     * @dev Can be called by the user, or by a contract authorized by the registry as long as the user has not revoked access
     * @param dest Address to which the call will be sent
     * @param howToCall Which kind of call to make
     * @param calldata Calldata to send
     * @return Result of the call (success or failure)
     */
    function proxy(address dest, HowToCall howToCall, bytes calldata)
        public
        returns (bool result)
    {
        require(msg.sender == user || (!revoked && registry.contracts(msg.sender)));
        if (howToCall == HowToCall.Call) {
            result = dest.call(calldata);
        } else if (howToCall == HowToCall.DelegateCall) {
            result = dest.delegatecall(calldata);
        }
        return result;
    }

    /**
     * Execute a message call and assert success
     * 
     * @dev Same functionality as `proxy`, just asserts the return value
     * @param dest Address to which the call will be sent
     * @param howToCall What kind of call to make
     * @param calldata Calldata to send
     */
    function proxyAssert(address dest, HowToCall howToCall, bytes calldata)
        public
    {
        require(proxy(dest, howToCall, calldata));
    }

}

contract Proxy {

  /**
  * @dev Tells the address of the implementation where every call will be delegated.
  * @return address of the implementation to which it will be delegated
  */
  function implementation() public view returns (address);

  /**
  * @dev Tells the type of proxy (EIP 897)
  * @return Type of proxy, 2 for upgradeable proxy
  */
  function proxyType() public pure returns (uint256 proxyTypeId);

  /**
  * @dev Fallback function allowing to perform a delegatecall to the given implementation.
  * This function will return whatever the implementation call returns
  */
  function () payable public {
    address _impl = implementation();
    require(_impl != address(0));

    assembly {
      let ptr := mload(0x40)
      calldatacopy(ptr, 0, calldatasize)
      let result := delegatecall(gas, _impl, ptr, calldatasize, 0, 0)
      let size := returndatasize
      returndatacopy(ptr, 0, size)

      switch result
      case 0 { revert(ptr, size) }
      default { return(ptr, size) }
    }
  }
}

contract OwnedUpgradeabilityProxy is Proxy, OwnedUpgradeabilityStorage {
  /**
  * @dev Event to show ownership has been transferred
  * @param previousOwner representing the address of the previous owner
  * @param newOwner representing the address of the new owner
  */
  event ProxyOwnershipTransferred(address previousOwner, address newOwner);

  /**
  * @dev This event will be emitted every time the implementation gets upgraded
  * @param implementation representing the address of the upgraded implementation
  */
  event Upgraded(address indexed implementation);

  /**
  * @dev Upgrades the implementation address
  * @param implementation representing the address of the new implementation to be set
  */
  function _upgradeTo(address implementation) internal {
    require(_implementation != implementation);
    _implementation = implementation;
    emit Upgraded(implementation);
  }

  /**
  * @dev Throws if called by any account other than the owner.
  */
  modifier onlyProxyOwner() {
    require(msg.sender == proxyOwner());
    _;
  }

  /**
   * @dev Tells the address of the proxy owner
   * @return the address of the proxy owner
   */
  function proxyOwner() public view returns (address) {
    return upgradeabilityOwner();
  }

  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferProxyOwnership(address newOwner) public onlyProxyOwner {
    require(newOwner != address(0));
    emit ProxyOwnershipTransferred(proxyOwner(), newOwner);
    setUpgradeabilityOwner(newOwner);
  }

  /**
   * @dev Allows the upgradeability owner to upgrade the current implementation of the proxy.
   * @param implementation representing the address of the new implementation to be set.
   */
  function upgradeTo(address implementation) public onlyProxyOwner {
    _upgradeTo(implementation);
  }

  /**
   * @dev Allows the upgradeability owner to upgrade the current implementation of the proxy
   * and delegatecall the new implementation for initialization.
   * @param implementation representing the address of the new implementation to be set.
   * @param data represents the msg.data to bet sent in the low level call. This parameter may include the function
   * signature of the implementation to be called with the needed payload
   */
  function upgradeToAndCall(address implementation, bytes data) payable public onlyProxyOwner {
    upgradeTo(implementation);
    require(address(this).delegatecall(data));
  }
}

contract OwnableDelegateProxy is OwnedUpgradeabilityProxy {

    constructor(address owner, address initialImplementation, bytes calldata)
        public
    {
        setUpgradeabilityOwner(owner);
        _upgradeTo(initialImplementation);
        require(initialImplementation.delegatecall(calldata));
    }

}

pragma solidity 0.8.11;

interface IERC721 {
    function safeTransferFrom(address from, address to, uint256 tokenId) external;
    function transferFrom(address from, address to, uint256 tokenId) external;
}

interface IERC1155 {
    function safeTransferFrom(address from, address to, uint256 tokenId, uint256 amount, bytes calldata data) external;
}

/// @title MerkleValidator enables matching trait-based and collection-based orders for ERC721 and ERC1155 tokens.
/// @author 0age
/// @dev This contract is intended to be called during atomicMatch_ via DELEGATECALL.
contract MerkleValidator {
    /// @dev InvalidProof is thrown on invalid proofs.
    error InvalidProof();

    /// @dev UnnecessaryProof is thrown in cases where a proof is supplied without a valid root to match against (root = 0)
    error UnnecessaryProof();

    /// @dev Match an ERC721 order, ensuring that the supplied proof demonstrates inclusion of the tokenId in the associated merkle root.
    /// @param from The account to transfer the ERC721 token from — this token must first be approved on the seller's AuthenticatedProxy contract.
    /// @param to The account to transfer the ERC721 token to.
    /// @param token The ERC721 token to transfer.
    /// @param tokenId The ERC721 tokenId to transfer.
    /// @param root A merkle root derived from each valid tokenId — set to 0 to indicate a collection-level or tokenId-specific order.
    /// @param proof A proof that the supplied tokenId is contained within the associated merkle root. Must be length 0 if root is not set.
    /// @return A boolean indicating a successful match and transfer.
    function matchERC721UsingCriteria(
        address from,
        address to,
        IERC721 token,
        uint256 tokenId,
        bytes32 root,
        bytes32[] calldata proof
    ) external returns (bool) {
    	// Proof verification is performed when there's a non-zero root.
    	if (root != bytes32(0)) {
    		_verifyProof(tokenId, root, proof);
    	} else if (proof.length != 0) {
    		// A root of zero should never have a proof.
    		revert UnnecessaryProof();
    	}

    	// Transfer the token.
        token.transferFrom(from, to, tokenId);

        return true;
    }

    /// @dev Match an ERC721 order using `safeTransferFrom`, ensuring that the supplied proof demonstrates inclusion of the tokenId in the associated merkle root.
    /// @param from The account to transfer the ERC721 token from — this token must first be approved on the seller's AuthenticatedProxy contract.
    /// @param to The account to transfer the ERC721 token to.
    /// @param token The ERC721 token to transfer.
    /// @param tokenId The ERC721 tokenId to transfer.
    /// @param root A merkle root derived from each valid tokenId — set to 0 to indicate a collection-level or tokenId-specific order.
    /// @param proof A proof that the supplied tokenId is contained within the associated merkle root. Must be length 0 if root is not set.
    /// @return A boolean indicating a successful match and transfer.
    function matchERC721WithSafeTransferUsingCriteria(
        address from,
        address to,
        IERC721 token,
        uint256 tokenId,
        bytes32 root,
        bytes32[] calldata proof
    ) external returns (bool) {
        // Proof verification is performed when there's a non-zero root.
        if (root != bytes32(0)) {
            _verifyProof(tokenId, root, proof);
        } else if (proof.length != 0) {
            // A root of zero should never have a proof.
            revert UnnecessaryProof();
        }

        // Transfer the token.
        token.safeTransferFrom(from, to, tokenId);

        return true;
    }

    /// @dev Match an ERC1155 order, ensuring that the supplied proof demonstrates inclusion of the tokenId in the associated merkle root.
    /// @param from The account to transfer the ERC1155 token from — this token must first be approved on the seller's AuthenticatedProxy contract.
    /// @param to The account to transfer the ERC1155 token to.
    /// @param token The ERC1155 token to transfer.
    /// @param tokenId The ERC1155 tokenId to transfer.
    /// @param amount The amount of ERC1155 tokens with the given tokenId to transfer.
    /// @param root A merkle root derived from each valid tokenId — set to 0 to indicate a collection-level or tokenId-specific order.
    /// @param proof A proof that the supplied tokenId is contained within the associated merkle root. Must be length 0 if root is not set.
    /// @return A boolean indicating a successful match and transfer.
    function matchERC1155UsingCriteria(
        address from,
        address to,
        IERC1155 token,
        uint256 tokenId,
        uint256 amount,
        bytes32 root,
        bytes32[] calldata proof
    ) external returns (bool) {
        // Proof verification is performed when there's a non-zero root.
        if (root != bytes32(0)) {
            _verifyProof(tokenId, root, proof);
        } else if (proof.length != 0) {
            // A root of zero should never have a proof.
            revert UnnecessaryProof();
        }

        // Transfer the token.
        token.safeTransferFrom(from, to, tokenId, amount, "");

        return true;
    }

    /// @dev Ensure that a given tokenId is contained within a supplied merkle root using a supplied proof.
    /// @param leaf The tokenId.
    /// @param root A merkle root derived from each valid tokenId.
    /// @param proof A proof that the supplied tokenId is contained within the associated merkle root.
    function _verifyProof(
        uint256 leaf,
        bytes32 root,
        bytes32[] memory proof
    ) private pure {
        bytes32 computedHash = bytes32(leaf);
        for (uint256 i = 0; i < proof.length; i++) {
            bytes32 proofElement = proof[i];
            if (computedHash <= proofElement) {
                // Hash(current computed hash + current element of the proof)
                computedHash = _efficientHash(computedHash, proofElement);
            } else {
                // Hash(current element of the proof + current computed hash)
                computedHash = _efficientHash(proofElement, computedHash);
            }
        }
        if (computedHash != root) {
            revert InvalidProof();
        }
    }

    /// @dev Efficiently hash two bytes32 elements using memory scratch space.
    /// @param a The first element included in the hash.
    /// @param b The second element included in the hash.
    /// @return value The resultant hash of the two bytes32 elements.
    function _efficientHash(
        bytes32 a,
        bytes32 b
    ) private pure returns (bytes32 value) {
        assembly {
            mstore(0x00, a)
            mstore(0x20, b)
            value := keccak256(0x00, 0x40)
        }
    }
}