// File: contracts/ERC721/ERC721ReceiverDraft.sol

pragma solidity ^0.4.24;


/// @title ERC721ReceiverDraft
/// @dev Interface for any contract that wants to support safeTransfers from
///  ERC721 asset contracts.
/// @dev Note: this is the interface defined from 
///  https://github.com/ethereum/EIPs/commit/2bddd126def7c046e1e62408dc2b51bdd9e57f0f
///  to https://github.com/ethereum/EIPs/commit/27788131d5975daacbab607076f2ee04624f9dbb 
///  and is not the final interface.
///  Due to the extended period of time this revision was specified in the draft,
///  we are supporting both this and the newer (final) interface in order to be 
///  compatible with any ERC721 implementations that may have used this interface.
contract ERC721ReceiverDraft {

    /// @dev Magic value to be returned upon successful reception of an NFT
    ///  Equals to `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`,
    ///  which can be also obtained as `ERC721ReceiverDraft(0).onERC721Received.selector`
    /// @dev see https://github.com/ethereum/EIPs/commit/2bddd126def7c046e1e62408dc2b51bdd9e57f0f
    bytes4 internal constant ERC721_RECEIVED_DRAFT = 0xf0b9e5ba;

    /// @notice Handle the receipt of an NFT
    /// @dev The ERC721 smart contract calls this function on the recipient
    ///  after a `transfer`. This function MAY throw to revert and reject the
    ///  transfer. This function MUST use 50,000 gas or less. Return of other
    ///  than the magic value MUST result in the transaction being reverted.
    ///  Note: the contract address is always the message sender.
    /// @param _from The sending address 
    /// @param _tokenId The NFT identifier which is being transfered
    /// @param data Additional data with no specified format
    /// @return `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`
    ///  unless throwing
    function onERC721Received(address _from, uint256 _tokenId, bytes data) external returns(bytes4);
}

// File: contracts/ERC721/ERC721ReceiverFinal.sol

pragma solidity ^0.4.24;


/// @title ERC721ReceiverFinal
/// @notice Interface for any contract that wants to support safeTransfers from
///  ERC721 asset contracts.
///  @dev Note: this is the final interface as defined at http://erc721.org
contract ERC721ReceiverFinal {

    /// @dev Magic value to be returned upon successful reception of an NFT
    ///  Equals to `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`,
    ///  which can be also obtained as `ERC721ReceiverFinal(0).onERC721Received.selector`
    /// @dev see https://github.com/OpenZeppelin/openzeppelin-solidity/blob/v1.12.0/contracts/token/ERC721/ERC721Receiver.sol
    bytes4 internal constant ERC721_RECEIVED_FINAL = 0x150b7a02;

    /// @notice Handle the receipt of an NFT
    /// @dev The ERC721 smart contract calls this function on the recipient
    /// after a `safetransfer`. This function MAY throw to revert and reject the
    /// transfer. Return of other than the magic value MUST result in the
    /// transaction being reverted.
    /// Note: the contract address is always the message sender.
    /// @param _operator The address which called `safeTransferFrom` function
    /// @param _from The address which previously owned the token
    /// @param _tokenId The NFT identifier which is being transferred
    /// @param _data Additional data with no specified format
    /// @return `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
    function onERC721Received(
        address _operator,
        address _from,
        uint256 _tokenId,
        bytes _data
    )
    public
        returns (bytes4);
}

// File: contracts/ERC721/ERC721Receivable.sol

pragma solidity ^0.4.24;



/// @title ERC721Receivable handles the reception of ERC721 tokens
///  See ERC721 specification
/// @author Christopher Scott
/// @dev These functions are public, and could be called by anyone, even in the case
///  where no NFTs have been transferred. Since it's not a reliable source of
///  truth about ERC721 tokens being transferred, we save the gas and don't
///  bother emitting a (potentially spurious) event as found in 
///  https://github.com/OpenZeppelin/openzeppelin-solidity/blob/5471fc808a17342d738853d7bf3e9e5ef3108074/contracts/mocks/ERC721ReceiverMock.sol
contract ERC721Receivable is ERC721ReceiverDraft, ERC721ReceiverFinal {

    /// @notice Handle the receipt of an NFT
    /// @dev The ERC721 smart contract calls this function on the recipient
    ///  after a `transfer`. This function MAY throw to revert and reject the
    ///  transfer. This function MUST use 50,000 gas or less. Return of other
    ///  than the magic value MUST result in the transaction being reverted.
    ///  Note: the contract address is always the message sender.
    /// @param _from The sending address 
    /// @param _tokenId The NFT identifier which is being transfered
    /// @param data Additional data with no specified format
    /// @return `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`
    ///  unless throwing
    function onERC721Received(address _from, uint256 _tokenId, bytes data) external returns(bytes4) {
        _from;
        _tokenId;
        data;

        // emit ERC721Received(_operator, _from, _tokenId, _data, gasleft());

        return ERC721_RECEIVED_DRAFT;
    }

    /// @notice Handle the receipt of an NFT
    /// @dev The ERC721 smart contract calls this function on the recipient
    /// after a `safetransfer`. This function MAY throw to revert and reject the
    /// transfer. Return of other than the magic value MUST result in the
    /// transaction being reverted.
    /// Note: the contract address is always the message sender.
    /// @param _operator The address which called `safeTransferFrom` function
    /// @param _from The address which previously owned the token
    /// @param _tokenId The NFT identifier which is being transferred
    /// @param _data Additional data with no specified format
    /// @return `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
    function onERC721Received(
        address _operator,
        address _from,
        uint256 _tokenId,
        bytes _data
    )
        public
        returns(bytes4)
    {
        _operator;
        _from;
        _tokenId;
        _data;

        // emit ERC721Received(_operator, _from, _tokenId, _data, gasleft());

        return ERC721_RECEIVED_FINAL;
    }

}

// File: contracts/ERC223/ERC223Receiver.sol

pragma solidity ^0.4.24;


/// @title ERC223Receiver ensures we are ERC223 compatible
/// @author Christopher Scott
contract ERC223Receiver {
    
    bytes4 public constant ERC223_ID = 0xc0ee0b8a;

    struct TKN {
        address sender;
        uint value;
        bytes data;
        bytes4 sig;
    }
    
    /// @notice tokenFallback is called from an ERC223 compatible contract
    /// @param _from the address from which the token was sent
    /// @param _value the amount of tokens sent
    /// @param _data the data sent with the transaction
    function tokenFallback(address _from, uint _value, bytes _data) public pure {
        _from;
        _value;
        _data;
    //   TKN memory tkn;
    //   tkn.sender = _from;
    //   tkn.value = _value;
    //   tkn.data = _data;
    //   uint32 u = uint32(_data[3]) + (uint32(_data[2]) << 8) + (uint32(_data[1]) << 16) + (uint32(_data[0]) << 24);
    //   tkn.sig = bytes4(u);
      
      /* tkn variable is analogue of msg variable of Ether transaction
      *  tkn.sender is person who initiated this token transaction   (analogue of msg.sender)
      *  tkn.value the number of tokens that were sent   (analogue of msg.value)
      *  tkn.data is data of token transaction   (analogue of msg.data)
      *  tkn.sig is 4 bytes signature of function
      *  if data of token transaction is a function execution
      */

    }
}

// File: contracts/ERC1271/ERC1271.sol

pragma solidity ^0.4.24;

contract ERC1271 {

    /// @dev bytes4(keccak256("isValidSignature(bytes32,bytes)")
    bytes4 internal constant ERC1271_VALIDSIGNATURE = 0x1626ba7e;

    /// @dev Should return whether the signature provided is valid for the provided data
    /// @param hash 32-byte hash of the data that is signed
    /// @param _signature Signature byte array associated with _data
    ///  MUST return the bytes4 magic value 0x1626ba7e when function passes.
    ///  MUST NOT modify state (using STATICCALL for solc < 0.5, view modifier for solc > 0.5)
    ///  MUST allow external calls
    function isValidSignature(
        bytes32 hash, 
        bytes _signature)
        external
        view 
        returns (bytes4);
}

// File: contracts/ECDSA.sol

pragma solidity ^0.4.24;


/// @title ECDSA is a library that contains useful methods for working with ECDSA signatures
library ECDSA {

    /// @notice Extracts the r, s, and v components from the `sigData` field starting from the `offset`
    /// @dev Note: does not do any bounds checking on the arguments!
    /// @param sigData the signature data; could be 1 or more packed signatures.
    /// @param offset the offset in sigData from which to start unpacking the signature components.
    function extractSignature(bytes sigData, uint256 offset) internal pure returns  (bytes32 r, bytes32 s, uint8 v) {
        // Divide the signature in r, s and v variables
        // ecrecover takes the signature parameters, and the only way to get them
        // currently is to use assembly.
        // solium-disable-next-line security/no-inline-assembly
        assembly {
             let dataPointer := add(sigData, offset)
             r := mload(add(dataPointer, 0x20))
             s := mload(add(dataPointer, 0x40))
             v := byte(0, mload(add(dataPointer, 0x60)))
        }
    
        return (r, s, v);
    }
}

// File: contracts/Wallet/CoreWallet.sol

pragma solidity ^0.4.24;






/// @title Core Wallet
/// @notice A basic smart contract wallet with cosigner functionality. The notion of "cosigner" is
///  the simplest possible multisig solution, a two-of-two signature scheme. It devolves nicely
///  to "one-of-one" (i.e. singlesig) by simply having the cosigner set to the same value as
///  the main signer.
/// 
///  Most "advanced" functionality (deadman's switch, multiday recovery flows, blacklisting, etc)
///  can be implemented externally to this smart contract, either as an additional smart contract
///  (which can be tracked as a signer without cosigner, or as a cosigner) or as an off-chain flow
///  using a public/private key pair as cosigner. Of course, the basic cosigning functionality could
///  also be implemented in this way, but (A) the complexity and gas cost of two-of-two multisig (as
///  implemented here) is negligable even if you don't need the cosigner functionality, and
///  (B) two-of-two multisig (as implemented here) handles a lot of really common use cases, most
///  notably third-party gas payment and off-chain blacklisting and fraud detection.
contract CoreWallet is ERC721Receivable, ERC223Receiver, ERC1271  {

    using ECDSA for bytes;

    /// @notice We require that presigned transactions use the EIP-191 signing format.
    ///  See that EIP for more info: https://github.com/ethereum/EIPs/blob/master/EIPS/eip-191.md
    byte public constant EIP191_VERSION_DATA = byte(0);
    byte public constant EIP191_PREFIX = byte(0x19);

    /// @notice This is the version of the contract.
    string public constant VERSION = "1.0.0";

    /// @notice A pre-shifted "1", used to increment the authVersion, so we can "prepend"
    ///  the authVersion to an address (for lookups in the authorizations mapping)
    ///  by using the '+' operator (which is cheaper than a shift and a mask). See the
    ///  comment on the `authorizations` variable for how this is used.
    uint256 public constant AUTH_VERSION_INCREMENTOR = (1 << 160);
    
    /// @notice The pre-shifted authVersion (to get the current authVersion as an integer,
    ///  shift this value right by 160 bits). Starts as `1 << 160` (`AUTH_VERSION_INCREMENTOR`)
    ///  See the comment on the `authorizations` variable for how this is used.
    uint256 public authVersion;

    /// @notice A mapping containing all of the addresses that are currently authorized to manage
    ///  the assets owned by this wallet.
    ///
    ///  The keys in this mapping are authorized addresses with a version number prepended,
    ///  like so: (authVersion,96)(address,160). The current authVersion MUST BE included
    ///  for each look-up; this allows us to effectively clear the entire mapping of its
    ///  contents merely by incrementing the authVersion variable. (This is important for
    ///  the emergencyRecovery() method.) Inspired by https://ethereum.stackexchange.com/a/42540
    ///
    ///  The values in this mapping are 256bit words, whose lower 20 bytes constitute "cosigners"
    ///  for each address. If an address maps to itself, then that address is said to have no cosigner.
    ///
    ///  The upper 12 bytes are reserved for future meta-data purposes.  The meta-data could refer
    ///  to the key (authorized address) or the value (cosigner) of the mapping.
    ///
    ///  Addresses that map to a non-zero cosigner in the current authVersion are called
    ///  "authorized addresses".
    mapping(uint256 => uint256) public authorizations;

    /// @notice A per-key nonce value, incremented each time a transaction is processed with that key.
    ///  Used for replay prevention. The nonce value in the transaction must exactly equal the current
    ///  nonce value in the wallet for that key. (This mirrors the way Ethereum's transaction nonce works.)
    mapping(address => uint256) public nonces;

    /// @notice A special address that is authorized to call `emergencyRecovery()`. That function
    ///  resets ALL authorization for this wallet, and must therefore be treated with utmost security.
    ///  Reasonable choices for recoveryAddress include:
    ///       - the address of a private key in cold storage
    ///       - a physically secured hardware wallet
    ///       - a multisig smart contract, possibly with a time-delayed challenge period
    ///       - the zero address, if you like performing without a safety net ;-)
    address public recoveryAddress;

    /// @notice Used to track whether or not this contract instance has been initialized. This
    ///  is necessary since it is common for this wallet smart contract to be used as the "library
    ///  code" for an clone contract. See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-1167.md
    ///  for more information about clone contracts.
    bool public initialized;
    
    /// @notice Used to decorate methods that can only be called directly by the recovery address.
    modifier onlyRecoveryAddress() {
        require(msg.sender == recoveryAddress, "sender must be recovery address");
        _;
    }

    /// @notice Used to decorate the `init` function so this can only be called one time. Necessary
    ///  since this contract will often be used as a "clone". (See above.)
    modifier onlyOnce() {
        require(!initialized, "must not already be initialized");
        initialized = true;
        _;
    }
    
    /// @notice Used to decorate methods that can only be called indirectly via an `invoke()` method.
    ///  In practice, it means that those methods can only be called by a signer/cosigner
    ///  pair that is currently authorized. Theoretically, we could factor out the
    ///  signer/cosigner verification code and use it explicitly in this modifier, but that
    ///  would either result in duplicated code, or additional overhead in the invoke()
    ///  calls (due to the stack manipulation for calling into the shared verification function).
    ///  Doing it this way makes calling the administration functions more expensive (since they
    ///  go through a explict call() instead of just branching within the contract), but it
    ///  makes invoke() more efficient. We assume that invoke() will be used much, much more often
    ///  than any of the administration functions.
    modifier onlyInvoked() {
        require(msg.sender == address(this), "must be called from `invoke()`");
        _;
    }
    
    /// @notice Emitted when an authorized address is added, removed, or modified. When an
    ///  authorized address is removed ("deauthorized"), cosigner will be address(0) in
    ///  this event.
    ///  
    ///  NOTE: When emergencyRecovery() is called, all existing addresses are deauthorized
    ///  WITHOUT Authorized(addr, 0) being emitted. If you are keeping an off-chain mirror of
    ///  authorized addresses, you must also watch for EmergencyRecovery events.
    /// @dev hash is 0xf5a7f4fb8a92356e8c8c4ae7ac3589908381450500a7e2fd08c95600021ee889
    /// @param authorizedAddress the address to authorize or unauthorize
    /// @param cosigner the 2-of-2 signatory (optional).
    event Authorized(address authorizedAddress, uint256 cosigner);
    
    /// @notice Emitted when an emergency recovery has been performed. If this event is fired,
    ///  ALL previously authorized addresses have been deauthorized and the only authorized
    ///  address is the authorizedAddress indicated in this event.
    /// @dev hash is 0xe12d0bbeb1d06d7a728031056557140afac35616f594ef4be227b5b172a604b5
    /// @param authorizedAddress the new authorized address
    /// @param cosigner the cosigning address for `authorizedAddress`
    event EmergencyRecovery(address authorizedAddress, uint256 cosigner);

    /// @notice Emitted when the recovery address changes. Either (but not both) of the
    ///  parameters may be zero.
    /// @dev hash is 0x568ab3dedd6121f0385e007e641e74e1f49d0fa69cab2957b0b07c4c7de5abb6
    /// @param previousRecoveryAddress the previous recovery address
    /// @param newRecoveryAddress the new recovery address
    event RecoveryAddressChanged(address previousRecoveryAddress, address newRecoveryAddress);

    /// @dev Emitted when this contract receives a non-zero amount ether via the fallback function
    ///  (i.e. This event is not fired if the contract receives ether as part of a method invocation)
    /// @param from the address which sent you ether
    /// @param value the amount of ether sent
    event Received(address from, uint value);

    /// @notice Emitted whenever a transaction is processed sucessfully from this wallet. Includes
    ///  both simple send ether transactions, as well as other smart contract invocations.
    /// @dev hash is 0x101214446435ebbb29893f3348e3aae5ea070b63037a3df346d09d3396a34aee
    /// @param hash The hash of the entire operation set. 0 is returned when emitted from `invoke0()`.
    /// @param result A bitfield of the results of the operations. A bit of 0 means success, and 1 means failure.
    /// @param numOperations A count of the number of operations processed
    event InvocationSuccess(
        bytes32 hash,
        uint256 result,
        uint256 numOperations
    );

    /// @notice The shared initialization code used to setup the contract state regardless of whether or
    ///  not the clone pattern is being used.
    /// @param _authorizedAddress the initial authorized address, must not be zero!
    /// @param _cosigner the initial cosigning address for `_authorizedAddress`, can be equal to `_authorizedAddress`
    /// @param _recoveryAddress the initial recovery address for the wallet, can be address(0)
    function init(address _authorizedAddress, uint256 _cosigner, address _recoveryAddress) public onlyOnce {
        require(_authorizedAddress != _recoveryAddress, "Do not use the recovery address as an authorized address.");
        require(address(_cosigner) != _recoveryAddress, "Do not use the recovery address as a cosigner.");
        require(_authorizedAddress != address(0), "Authorized addresses must not be zero.");
        require(address(_cosigner) != address(0), "Initial cosigner must not be zero.");
        
        recoveryAddress = _recoveryAddress;
        // set initial authorization value
        authVersion = AUTH_VERSION_INCREMENTOR;
        // add initial authorized address
        authorizations[authVersion + uint256(_authorizedAddress)] = _cosigner;
        
        emit Authorized(_authorizedAddress, _cosigner);
    }

    /// @notice The fallback function, invoked whenever we receive a transaction that doesn't call any of our
    ///  named functions. In particular, this method is called when we are the target of a simple send transaction
    ///  or when someone tries to call a method that we don't implement. We assume that a "correct" invocation of
    ///  this method only occurs when someone is trying to transfer ether to this wallet, in which case and the
    ///  `msg.data.length` will be 0.
    ///
    ///  NOTE: Some smart contracts send 0 eth as part of a more complex
    ///  operation (-cough- CryptoKitties -cough-) ; ideally, we'd `require(msg.value > 0)` here, but to work
    ///  with those kinds of smart contracts, we accept zero sends and just skip logging in that case.
    function() external payable {
        require(msg.data.length == 0, "Invalid transaction.");
        if (msg.value > 0) {
            emit Received(msg.sender, msg.value);
        }
    }
    
    /// @notice Configures an authorizable address. Can be used in four ways:
    ///   - Add a new signer/cosigner pair (cosigner must be non-zero)
    ///   - Set or change the cosigner for an existing signer (if authorizedAddress != cosigner)
    ///   - Remove the cosigning requirement for a signer (if authorizedAddress == cosigner)
    ///   - Remove a signer (if cosigner == address(0))
    /// @dev Must be called through `invoke()`
    /// @param _authorizedAddress the address to configure authorization
    /// @param _cosigner the corresponding cosigning address
    function setAuthorized(address _authorizedAddress, uint256 _cosigner) external onlyInvoked {
        // TODO: Allowing a signer to remove itself is actually pretty terrible; it could result in the user
        //  removing their only available authorized key. Unfortunately, due to how the invocation forwarding
        //  works, we don't actually _know_ which signer was used to call this method, so there's no easy way
        //  to prevent this.
        
        // TODO: Allowing the backup key to be set as an authorized address bypasses the recovery mechanisms.
        //  Dapper can prevent this with offchain logic and the cosigner, but it would be nice to have 
        //  this enforced by the smart contract logic itself.
        
        require(_authorizedAddress != address(0), "Authorized addresses must not be zero.");
        require(_authorizedAddress != recoveryAddress, "Do not use the recovery address as an authorized address.");
        require(address(_cosigner) == address(0) || address(_cosigner) != recoveryAddress, "Do not use the recovery address as a cosigner.");
 
        authorizations[authVersion + uint256(_authorizedAddress)] = _cosigner;
        emit Authorized(_authorizedAddress, _cosigner);
    }
    
    /// @notice Performs an emergency recovery operation, removing all existing authorizations and setting
    ///  a sole new authorized address with optional cosigner. THIS IS A SCORCHED EARTH SOLUTION, and great
    ///  care should be taken to ensure that this method is never called unless it is a last resort. See the
    ///  comments above about the proper kinds of addresses to use as the recoveryAddress to ensure this method
    ///  is not trivially abused.
    /// @param _authorizedAddress the new and sole authorized address
    /// @param _cosigner the corresponding cosigner address, can be equal to _authorizedAddress
    function emergencyRecovery(address _authorizedAddress, uint256 _cosigner) external onlyRecoveryAddress {
        require(_authorizedAddress != address(0), "Authorized addresses must not be zero.");
        require(_authorizedAddress != recoveryAddress, "Do not use the recovery address as an authorized address.");
        require(address(_cosigner) != address(0), "The cosigner must not be zero.");

        // Incrementing the authVersion number effectively erases the authorizations mapping. See the comments
        // on the authorizations variable (above) for more information.
        authVersion += AUTH_VERSION_INCREMENTOR;

        // Store the new signer/cosigner pair as the only remaining authorized address
        authorizations[authVersion + uint256(_authorizedAddress)] = _cosigner;
        emit EmergencyRecovery(_authorizedAddress, _cosigner);
    }

    /// @notice Sets the recovery address, which can be zero (indicating that no recovery is possible)
    ///  Can be updated by any authorized address. This address should be set with GREAT CARE. See the
    ///  comments above about the proper kinds of addresses to use as the recoveryAddress to ensure this
    ///  mechanism is not trivially abused.
    /// @dev Must be called through `invoke()`
    /// @param _recoveryAddress the new recovery address
    function setRecoveryAddress(address _recoveryAddress) external onlyInvoked {
        require(
            address(authorizations[authVersion + uint256(_recoveryAddress)]) == address(0),
            "Do not use an authorized address as the recovery address."
        );
 
        address previous = recoveryAddress;
        recoveryAddress = _recoveryAddress;

        emit RecoveryAddressChanged(previous, recoveryAddress);
    }

    /// @notice Allows ANY caller to recover gas by way of deleting old authorization keys after
    ///  a recovery operation. Anyone can call this method to delete the old unused storage and
    ///  get themselves a bit of gas refund in the bargin.
    /// @dev keys must be known to caller or else nothing is refunded
    /// @param _version the version of the mapping which you want to delete (unshifted)
    /// @param _keys the authorization keys to delete 
    function recoverGas(uint256 _version, address[] _keys) external {
        // TODO: should this be 0xffffffffffffffffffffffff ?
        require(_version > 0 && _version < 0xffffffff, "Invalid version number.");
        
        uint256 shiftedVersion = _version << 160;

        require(shiftedVersion < authVersion, "You can only recover gas from expired authVersions.");

        for (uint256 i = 0; i < _keys.length; ++i) {
            delete(authorizations[shiftedVersion + uint256(_keys[i])]);
        }
    }

    /// @notice Should return whether the signature provided is valid for the provided data
    ///  See https://github.com/ethereum/EIPs/issues/1271
    /// @dev This function meets the following conditions as per the EIP:
    ///  MUST return the bytes4 magic value `0x1626ba7e` when function passes.
    ///  MUST NOT modify state (using `STATICCALL` for solc < 0.5, `view` modifier for solc > 0.5)
    ///  MUST allow external calls
    /// @param hash A 32 byte hash of the signed data.  The actual hash that is hashed however is the
    ///  the following tightly packed arguments: `0x19,0x0,wallet_address,hash`
    /// @param _signature Signature byte array associated with `_data`
    /// @return Magic value `0x1626ba7e` upon success, 0 otherwise.
    function isValidSignature(bytes32 hash, bytes _signature) external view returns (bytes4) {
        
        // We 'hash the hash' for the following reasons:
        // 1. `hash` is not the hash of an Ethereum transaction
        // 2. signature must target this wallet to avoid replaying the signature for another wallet
        // with the same key
        // 3. Gnosis does something similar: 
        // https://github.com/gnosis/safe-contracts/blob/102e632d051650b7c4b0a822123f449beaf95aed/contracts/GnosisSafe.sol
        bytes32 operationHash = keccak256(
            abi.encodePacked(
            EIP191_PREFIX,
            EIP191_VERSION_DATA,
            this,
            hash));

        bytes32[2] memory r;
        bytes32[2] memory s;
        uint8[2] memory v;
        address signer;
        address cosigner;

        // extract 1 or 2 signatures depending on length
        if (_signature.length == 65) {
            (r[0], s[0], v[0]) = _signature.extractSignature(0);
            signer = ecrecover(operationHash, v[0], r[0], s[0]);
            cosigner = signer;
        } else if (_signature.length == 130) {
            (r[0], s[0], v[0]) = _signature.extractSignature(0);
            (r[1], s[1], v[1]) = _signature.extractSignature(65);
            signer = ecrecover(operationHash, v[0], r[0], s[0]);
            cosigner = ecrecover(operationHash, v[1], r[1], s[1]);
        } else {
            return 0;
        }
            
        // check for valid signature
        if (signer == address(0)) {
            return 0;
        }

        // check for valid signature
        if (cosigner == address(0)) {
            return 0;
        }

        // check to see if this is an authorized key
        if (address(authorizations[authVersion + uint256(signer)]) != cosigner) {
            return 0;
        }

        return ERC1271_VALIDSIGNATURE;
    }

    /// @notice Query if a contract implements an interface
    /// @param interfaceID The interface identifier, as specified in ERC-165
    /// @dev Interface identification is specified in ERC-165. This function
    ///  uses less than 30,000 gas.
    /// @return `true` if the contract implements `interfaceID` and
    ///  `interfaceID` is not 0xffffffff, `false` otherwise
    function supportsInterface(bytes4 interfaceID) external pure returns (bool) {
        // I am not sure why the linter is complaining about the whitespace
        return
            interfaceID == this.supportsInterface.selector || // ERC165
            interfaceID == ERC721_RECEIVED_FINAL || // ERC721 Final
            interfaceID == ERC721_RECEIVED_DRAFT || // ERC721 Draft
            interfaceID == ERC223_ID || // ERC223
            interfaceID == ERC1271_VALIDSIGNATURE; // ERC1271
    }

    /// @notice A version of `invoke()` that has no explicit signatures, and uses msg.sender
    ///  as both the signer and cosigner. Will only succeed if `msg.sender` is an authorized
    ///  signer for this wallet, with no cosigner, saving transaction size and gas in that case.
    /// @param data The data containing the transactions to be invoked; see internalInvoke for details.
    function invoke0(bytes data) external {
        // The nonce doesn't need to be incremented for transactions that don't include explicit signatures;
        // the built-in nonce of the native ethereum transaction will protect against replay attacks, and we
        // can save the gas that would be spent updating the nonce variable

        // The operation should be approved if the signer address has no cosigner (i.e. signer == cosigner)
        require(address(authorizations[authVersion + uint256(msg.sender)]) == msg.sender, "Invalid authorization.");

        internalInvoke(0, data);
    }

    /// @notice A version of `invoke()` that has one explicit signature which is used to derive the authorized
    ///  address. Uses `msg.sender` as the cosigner.
    /// @param v the v value for the signature; see https://github.com/ethereum/EIPs/blob/master/EIPS/eip-155.md
    /// @param r the r value for the signature
    /// @param s the s value for the signature
    /// @param nonce the nonce value for the signature
    /// @param authorizedAddress the address of the authorization key; this is used here so that cosigner signatures are interchangeable
    ///  between this function and `invoke2()`
    /// @param data The data containing the transactions to be invoked; see internalInvoke for details.
    function invoke1CosignerSends(uint8 v, bytes32 r, bytes32 s, uint256 nonce, address authorizedAddress, bytes data) external {
        // check signature version
        require(v == 27 || v == 28, "Invalid signature version.");

        // calculate hash
        bytes32 operationHash = keccak256(
            abi.encodePacked(
            EIP191_PREFIX,
            EIP191_VERSION_DATA,
            this,
            nonce,
            authorizedAddress,
            data));
 
        // recover signer
        address signer = ecrecover(operationHash, v, r, s);

        // check for valid signature
        require(signer != address(0), "Invalid signature.");

        // check nonce
        require(nonce == nonces[signer], "must use correct nonce");

        // check signer
        require(signer == authorizedAddress, "authorized addresses must be equal");

        // Get cosigner
        address requiredCosigner = address(authorizations[authVersion + uint256(signer)]);
        
        // The operation should be approved if the signer address has no cosigner (i.e. signer == cosigner) or
        // if the actual cosigner matches the required cosigner.
        require(requiredCosigner == signer || requiredCosigner == msg.sender, "Invalid authorization.");

        // increment nonce to prevent replay attacks
        nonces[signer] = nonce + 1;

        // call internal function
        internalInvoke(operationHash, data);
    }

    /// @notice A version of `invoke()` that has one explicit signature which is used to derive the cosigning
    ///  address. Uses `msg.sender` as the authorized address.
    /// @param v the v value for the signature; see https://github.com/ethereum/EIPs/blob/master/EIPS/eip-155.md
    /// @param r the r value for the signature
    /// @param s the s value for the signature
    /// @param data The data containing the transactions to be invoked; see internalInvoke for details.
    function invoke1SignerSends(uint8 v, bytes32 r, bytes32 s, bytes data) external {
        // check signature version
        // `ecrecover` will infact return 0 if given invalid
        // so perhaps this check is redundant
        require(v == 27 || v == 28, "Invalid signature version.");
        
        uint256 nonce = nonces[msg.sender];

        // calculate hash
        bytes32 operationHash = keccak256(
            abi.encodePacked(
            EIP191_PREFIX,
            EIP191_VERSION_DATA,
            this,
            nonce,
            msg.sender,
            data));
 
        // recover cosigner
        address cosigner = ecrecover(operationHash, v, r, s);
        
        // check for valid signature
        require(cosigner != address(0), "Invalid signature.");

        // Get required cosigner
        address requiredCosigner = address(authorizations[authVersion + uint256(msg.sender)]);
        
        // The operation should be approved if the signer address has no cosigner (i.e. signer == cosigner) or
        // if the actual cosigner matches the required cosigner.
        require(requiredCosigner == cosigner || requiredCosigner == msg.sender, "Invalid authorization.");

        // increment nonce to prevent replay attacks
        nonces[msg.sender] = nonce + 1;
 
        internalInvoke(operationHash, data);
    }

    /// @notice A version of `invoke()` that has two explicit signatures, the first is used to derive the authorized
    ///  address, the second to derive the cosigner. The value of `msg.sender` is ignored.
    /// @param v the v values for the signatures
    /// @param r the r values for the signatures
    /// @param s the s values for the signatures
    /// @param nonce the nonce value for the signature
    /// @param authorizedAddress the address of the signer; forces the signature to be unique and tied to the signers nonce 
    /// @param data The data containing the transactions to be invoked; see internalInvoke for details.
    function invoke2(uint8[2] v, bytes32[2] r, bytes32[2] s, uint256 nonce, address authorizedAddress, bytes data) external {
        // check signature versions
        // `ecrecover` will infact return 0 if given invalid
        // so perhaps these checks are redundant
        require(v[0] == 27 || v[0] == 28, "invalid signature version v[0]");
        require(v[1] == 27 || v[1] == 28, "invalid signature version v[1]");
 
        bytes32 operationHash = keccak256(
            abi.encodePacked(
            EIP191_PREFIX,
            EIP191_VERSION_DATA,
            this,
            nonce,
            authorizedAddress,
            data));
 
        // recover signer and cosigner
        address signer = ecrecover(operationHash, v[0], r[0], s[0]);
        address cosigner = ecrecover(operationHash, v[1], r[1], s[1]);

        // check for valid signatures
        require(signer != address(0), "Invalid signature for signer.");
        require(cosigner != address(0), "Invalid signature for cosigner.");

        // check signer address
        require(signer == authorizedAddress, "authorized addresses must be equal");

        // check nonces
        require(nonce == nonces[signer], "must use correct nonce for signer");

        // Get Mapping
        address requiredCosigner = address(authorizations[authVersion + uint256(signer)]);
        
        // The operation should be approved if the signer address has no cosigner (i.e. signer == cosigner) or
        // if the actual cosigner matches the required cosigner.
        require(requiredCosigner == signer || requiredCosigner == cosigner, "Invalid authorization.");

        // increment nonce to prevent replay attacks
        nonces[signer]++;

        internalInvoke(operationHash, data);
    }

    /// @dev Internal invoke call, 
    /// @param operationHash The hash of the operation
    /// @param data The data to send to the `call()` operation
    ///  The data is prefixed with a global 1 byte revert flag
    ///  If revert is 1, then any revert from a `call()` operation is rethrown.
    ///  Otherwise, the error is recorded in the `result` field of the `InvocationSuccess` event.
    ///  Immediately following the revert byte (no padding), the data format is then is a series
    ///  of 1 or more tightly packed tuples:
    ///  `<target(20),amount(32),datalength(32),data>`
    ///  If `datalength == 0`, the data field must be omitted
    function internalInvoke(bytes32 operationHash, bytes data) internal {
        // keep track of the number of operations processed
        uint256 numOps;
        // keep track of the result of each operation as a bit
        uint256 result;

        // We need to store a reference to this string as a variable so we can use it as an argument to
        // the revert call from assembly.
        string memory invalidLengthMessage = "Data field too short";
        string memory callFailed = "Call failed";

        // At an absolute minimum, the data field must be at least 85 bytes
        // <revert(1), to_address(20), value(32), data_length(32)>
        require(data.length >= 85, invalidLengthMessage);

        // Forward the call onto its actual target. Note that the target address can be `self` here, which is
        // actually the required flow for modifying the configuration of the authorized keys and recovery address.
        //
        // The assembly code below loads data directly from memory, so the enclosing function must be marked `internal`
        assembly {
            // A cursor pointing to the revert flag, starts after the length field of the data object
            let memPtr := add(data, 32)

            // The revert flag is the leftmost byte from memPtr
            let revertFlag := byte(0, mload(memPtr))

            // A pointer to the end of the data object
            let endPtr := add(memPtr, mload(data))

            // Now, memPtr is a cursor pointing to the begining of the current sub-operation
            memPtr := add(memPtr, 1)

            // Loop through data, parsing out the various sub-operations
            for { } lt(memPtr, endPtr) { } {
                // Load the length of the call data of the current operation
                // 52 = to(20) + value(32)
                let len := mload(add(memPtr, 52))
                
                // Compute a pointer to the end of the current operation
                // 84 = to(20) + value(32) + size(32)
                let opEnd := add(len, add(memPtr, 84))

                // Bail if the current operation's data overruns the end of the enclosing data buffer
                // NOTE: Comment out this bit of code and uncomment the next section if you want
                // the solidity-coverage tool to work.
                // See https://github.com/sc-forks/solidity-coverage/issues/287
                if gt(opEnd, endPtr) {
                    // The computed end of this operation goes past the end of the data buffer. Not good!
                    revert(add(invalidLengthMessage, 32), mload(invalidLengthMessage))
                }
                // NOTE: Code that is compatible with solidity-coverage
                // switch gt(opEnd, endPtr)
                // case 1 {
                //     revert(add(invalidLengthMessage, 32), mload(invalidLengthMessage))
                // }

                // This line of code packs in a lot of functionality!
                //  - load the target address from memPtr, the address is only 20-bytes but mload always grabs 32-bytes,
                //    so we have to divide the result by 2^96 to effectively right-shift by 12 bytes.
                //  - load the value field, stored at memPtr+20
                //  - pass a pointer to the call data, stored at memPtr+84
                //  - use the previously loaded len field as the size of the call data
                //  - make the call (passing all remaining gas to the child call)
                //  - check the result (0 == reverted)
                if eq(0, call(gas, div(mload(memPtr), exp(2, 96)), mload(add(memPtr, 20)), add(memPtr, 84), len, 0, 0)) {
                    
                    switch revertFlag
                    case 1 {
                        revert(add(callFailed, 32), mload(callFailed))
                    }
                    default {
                        // mark this operation as failed
                        // create the appropriate bit, 'or' with previous
                        result := or(result, exp(2, numOps))
                    }
                }

                // increment our counter
                numOps := add(numOps, 1)
             
                // Update mem pointer to point to the next sub-operation
                memPtr := opEnd
            }
        }

        // emit single event upon success
        emit InvocationSuccess(operationHash, result, numOps);
    }
}

// File: contracts/Wallet/CloneableWallet.sol

pragma solidity ^0.4.24;



/// @title Cloneable Wallet
/// @notice This contract represents a complete but non working wallet.  
///  It is meant to be deployed and serve as the contract that you clone
///  in an EIP 1167 clone setup.
/// @dev See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-1167.md
/// @dev Currently, we are seeing approximatley 933 gas overhead for using
///  the clone wallet; use `FullWallet` if you think users will overtake
///  the transaction threshold over the lifetime of the wallet.
contract CloneableWallet is CoreWallet {

    /// @dev An empty constructor that deploys a NON-FUNCTIONAL version
    ///  of `CoreWallet`
    constructor () public {
        initialized = true;
    }
}

pragma solidity ^0.4.11;


/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
  address public owner;


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  function Ownable() {
    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) onlyOwner {
    if (newOwner != address(0)) {
      owner = newOwner;
    }
  }

}



/// @title Interface for contracts conforming to ERC-721: Non-Fungible Tokens
/// @author Dieter Shirley <[email protected]> (https://github.com/dete)
contract ERC721 {
    // Required methods
    function totalSupply() public view returns (uint256 total);
    function balanceOf(address _owner) public view returns (uint256 balance);
    function ownerOf(uint256 _tokenId) external view returns (address owner);
    function approve(address _to, uint256 _tokenId) external;
    function transfer(address _to, uint256 _tokenId) external;
    function transferFrom(address _from, address _to, uint256 _tokenId) external;

    // Events
    event Transfer(address from, address to, uint256 tokenId);
    event Approval(address owner, address approved, uint256 tokenId);

    // Optional
    // function name() public view returns (string name);
    // function symbol() public view returns (string symbol);
    // function tokensOfOwner(address _owner) external view returns (uint256[] tokenIds);
    // function tokenMetadata(uint256 _tokenId, string _preferredTransport) public view returns (string infoUrl);

    // ERC-165 Compatibility (https://github.com/ethereum/EIPs/issues/165)
    function supportsInterface(bytes4 _interfaceID) external view returns (bool);
}









/// @title Auction Core
/// @dev Contains models, variables, and internal methods for the auction.
/// @notice We omit a fallback function to prevent accidental sends to this contract.
contract ClockAuctionBase {

    // Represents an auction on an NFT
    struct Auction {
        // Current owner of NFT
        address seller;
        // Price (in wei) at beginning of auction
        uint128 startingPrice;
        // Price (in wei) at end of auction
        uint128 endingPrice;
        // Duration (in seconds) of auction
        uint64 duration;
        // Time when auction started
        // NOTE: 0 if this auction has been concluded
        uint64 startedAt;
    }

    // Reference to contract tracking NFT ownership
    ERC721 public nonFungibleContract;

    // Cut owner takes on each auction, measured in basis points (1/100 of a percent).
    // Values 0-10,000 map to 0%-100%
    uint256 public ownerCut;

    // Map from token ID to their corresponding auction.
    mapping (uint256 => Auction) tokenIdToAuction;

    event AuctionCreated(uint256 tokenId, uint256 startingPrice, uint256 endingPrice, uint256 duration);
    event AuctionSuccessful(uint256 tokenId, uint256 totalPrice, address winner);
    event AuctionCancelled(uint256 tokenId);

    /// @dev Returns true if the claimant owns the token.
    /// @param _claimant - Address claiming to own the token.
    /// @param _tokenId - ID of token whose ownership to verify.
    function _owns(address _claimant, uint256 _tokenId) internal view returns (bool) {
        return (nonFungibleContract.ownerOf(_tokenId) == _claimant);
    }

    /// @dev Escrows the NFT, assigning ownership to this contract.
    /// Throws if the escrow fails.
    /// @param _owner - Current owner address of token to escrow.
    /// @param _tokenId - ID of token whose approval to verify.
    function _escrow(address _owner, uint256 _tokenId) internal {
        // it will throw if transfer fails
        nonFungibleContract.transferFrom(_owner, this, _tokenId);
    }

    /// @dev Transfers an NFT owned by this contract to another address.
    /// Returns true if the transfer succeeds.
    /// @param _receiver - Address to transfer NFT to.
    /// @param _tokenId - ID of token to transfer.
    function _transfer(address _receiver, uint256 _tokenId) internal {
        // it will throw if transfer fails
        nonFungibleContract.transfer(_receiver, _tokenId);
    }

    /// @dev Adds an auction to the list of open auctions. Also fires the
    ///  AuctionCreated event.
    /// @param _tokenId The ID of the token to be put on auction.
    /// @param _auction Auction to add.
    function _addAuction(uint256 _tokenId, Auction _auction) internal {
        // Require that all auctions have a duration of
        // at least one minute. (Keeps our math from getting hairy!)
        require(_auction.duration >= 1 minutes);

        tokenIdToAuction[_tokenId] = _auction;

        AuctionCreated(
            uint256(_tokenId),
            uint256(_auction.startingPrice),
            uint256(_auction.endingPrice),
            uint256(_auction.duration)
        );
    }

    /// @dev Cancels an auction unconditionally.
    function _cancelAuction(uint256 _tokenId, address _seller) internal {
        _removeAuction(_tokenId);
        _transfer(_seller, _tokenId);
        AuctionCancelled(_tokenId);
    }

    /// @dev Computes the price and transfers winnings.
    /// Does NOT transfer ownership of token.
    function _bid(uint256 _tokenId, uint256 _bidAmount)
        internal
        returns (uint256)
    {
        // Get a reference to the auction struct
        Auction storage auction = tokenIdToAuction[_tokenId];

        // Explicitly check that this auction is currently live.
        // (Because of how Ethereum mappings work, we can't just count
        // on the lookup above failing. An invalid _tokenId will just
        // return an auction object that is all zeros.)
        require(_isOnAuction(auction));

        // Check that the bid is greater than or equal to the current price
        uint256 price = _currentPrice(auction);
        require(_bidAmount >= price);

        // Grab a reference to the seller before the auction struct
        // gets deleted.
        address seller = auction.seller;

        // The bid is good! Remove the auction before sending the fees
        // to the sender so we can't have a reentrancy attack.
        _removeAuction(_tokenId);

        // Transfer proceeds to seller (if there are any!)
        if (price > 0) {
            // Calculate the auctioneer's cut.
            // (NOTE: _computeCut() is guaranteed to return a
            // value <= price, so this subtraction can't go negative.)
            uint256 auctioneerCut = _computeCut(price);
            uint256 sellerProceeds = price - auctioneerCut;

            // NOTE: Doing a transfer() in the middle of a complex
            // method like this is generally discouraged because of
            // reentrancy attacks and DoS attacks if the seller is
            // a contract with an invalid fallback function. We explicitly
            // guard against reentrancy attacks by removing the auction
            // before calling transfer(), and the only thing the seller
            // can DoS is the sale of their own asset! (And if it's an
            // accident, they can call cancelAuction(). )
            seller.transfer(sellerProceeds);
        }

        // Calculate any excess funds included with the bid. If the excess
        // is anything worth worrying about, transfer it back to bidder.
        // NOTE: We checked above that the bid amount is greater than or
        // equal to the price so this cannot underflow.
        uint256 bidExcess = _bidAmount - price;

        // Return the funds. Similar to the previous transfer, this is
        // not susceptible to a re-entry attack because the auction is
        // removed before any transfers occur.
        msg.sender.transfer(bidExcess);

        // Tell the world!
        AuctionSuccessful(_tokenId, price, msg.sender);

        return price;
    }

    /// @dev Removes an auction from the list of open auctions.
    /// @param _tokenId - ID of NFT on auction.
    function _removeAuction(uint256 _tokenId) internal {
        delete tokenIdToAuction[_tokenId];
    }

    /// @dev Returns true if the NFT is on auction.
    /// @param _auction - Auction to check.
    function _isOnAuction(Auction storage _auction) internal view returns (bool) {
        return (_auction.startedAt > 0);
    }

    /// @dev Returns current price of an NFT on auction. Broken into two
    ///  functions (this one, that computes the duration from the auction
    ///  structure, and the other that does the price computation) so we
    ///  can easily test that the price computation works correctly.
    function _currentPrice(Auction storage _auction)
        internal
        view
        returns (uint256)
    {
        uint256 secondsPassed = 0;

        // A bit of insurance against negative values (or wraparound).
        // Probably not necessary (since Ethereum guarnatees that the
        // now variable doesn't ever go backwards).
        if (now > _auction.startedAt) {
            secondsPassed = now - _auction.startedAt;
        }

        return _computeCurrentPrice(
            _auction.startingPrice,
            _auction.endingPrice,
            _auction.duration,
            secondsPassed
        );
    }

    /// @dev Computes the current price of an auction. Factored out
    ///  from _currentPrice so we can run extensive unit tests.
    ///  When testing, make this function public and turn on
    ///  `Current price computation` test suite.
    function _computeCurrentPrice(
        uint256 _startingPrice,
        uint256 _endingPrice,
        uint256 _duration,
        uint256 _secondsPassed
    )
        internal
        pure
        returns (uint256)
    {
        // NOTE: We don't use SafeMath (or similar) in this function because
        //  all of our public functions carefully cap the maximum values for
        //  time (at 64-bits) and currency (at 128-bits). _duration is
        //  also known to be non-zero (see the require() statement in
        //  _addAuction())
        if (_secondsPassed >= _duration) {
            // We've reached the end of the dynamic pricing portion
            // of the auction, just return the end price.
            return _endingPrice;
        } else {
            // Starting price can be higher than ending price (and often is!), so
            // this delta can be negative.
            int256 totalPriceChange = int256(_endingPrice) - int256(_startingPrice);

            // This multiplication can't overflow, _secondsPassed will easily fit within
            // 64-bits, and totalPriceChange will easily fit within 128-bits, their product
            // will always fit within 256-bits.
            int256 currentPriceChange = totalPriceChange * int256(_secondsPassed) / int256(_duration);

            // currentPriceChange can be negative, but if so, will have a magnitude
            // less that _startingPrice. Thus, this result will always end up positive.
            int256 currentPrice = int256(_startingPrice) + currentPriceChange;

            return uint256(currentPrice);
        }
    }

    /// @dev Computes owner's cut of a sale.
    /// @param _price - Sale price of NFT.
    function _computeCut(uint256 _price) internal view returns (uint256) {
        // NOTE: We don't use SafeMath (or similar) in this function because
        //  all of our entry functions carefully cap the maximum values for
        //  currency (at 128-bits), and ownerCut <= 10000 (see the require()
        //  statement in the ClockAuction constructor). The result of this
        //  function is always guaranteed to be <= _price.
        return _price * ownerCut / 10000;
    }

}







/**
 * @title Pausable
 * @dev Base contract which allows children to implement an emergency stop mechanism.
 */
contract Pausable is Ownable {
  event Pause();
  event Unpause();

  bool public paused = false;


  /**
   * @dev modifier to allow actions only when the contract IS paused
   */
  modifier whenNotPaused() {
    require(!paused);
    _;
  }

  /**
   * @dev modifier to allow actions only when the contract IS NOT paused
   */
  modifier whenPaused {
    require(paused);
    _;
  }

  /**
   * @dev called by the owner to pause, triggers stopped state
   */
  function pause() onlyOwner whenNotPaused returns (bool) {
    paused = true;
    Pause();
    return true;
  }

  /**
   * @dev called by the owner to unpause, returns to normal state
   */
  function unpause() onlyOwner whenPaused returns (bool) {
    paused = false;
    Unpause();
    return true;
  }
}


/// @title Clock auction for non-fungible tokens.
/// @notice We omit a fallback function to prevent accidental sends to this contract.
contract ClockAuction is Pausable, ClockAuctionBase {

    /// @dev The ERC-165 interface signature for ERC-721.
    ///  Ref: https://github.com/ethereum/EIPs/issues/165
    ///  Ref: https://github.com/ethereum/EIPs/issues/721
    bytes4 constant InterfaceSignature_ERC721 = bytes4(0x9a20483d);

    /// @dev Constructor creates a reference to the NFT ownership contract
    ///  and verifies the owner cut is in the valid range.
    /// @param _nftAddress - address of a deployed contract implementing
    ///  the Nonfungible Interface.
    /// @param _cut - percent cut the owner takes on each auction, must be
    ///  between 0-10,000.
    function ClockAuction(address _nftAddress, uint256 _cut) public {
        require(_cut <= 10000);
        ownerCut = _cut;

        ERC721 candidateContract = ERC721(_nftAddress);
        require(candidateContract.supportsInterface(InterfaceSignature_ERC721));
        nonFungibleContract = candidateContract;
    }

    /// @dev Remove all Ether from the contract, which is the owner's cuts
    ///  as well as any Ether sent directly to the contract address.
    ///  Always transfers to the NFT contract, but can be called either by
    ///  the owner or the NFT contract.
    function withdrawBalance() external {
        address nftAddress = address(nonFungibleContract);

        require(
            msg.sender == owner ||
            msg.sender == nftAddress
        );
        // We are using this boolean method to make sure that even if one fails it will still work
        bool res = nftAddress.send(this.balance);
    }

    /// @dev Creates and begins a new auction.
    /// @param _tokenId - ID of token to auction, sender must be owner.
    /// @param _startingPrice - Price of item (in wei) at beginning of auction.
    /// @param _endingPrice - Price of item (in wei) at end of auction.
    /// @param _duration - Length of time to move between starting
    ///  price and ending price (in seconds).
    /// @param _seller - Seller, if not the message sender
    function createAuction(
        uint256 _tokenId,
        uint256 _startingPrice,
        uint256 _endingPrice,
        uint256 _duration,
        address _seller
    )
        external
        whenNotPaused
    {
        // Sanity check that no inputs overflow how many bits we've allocated
        // to store them in the auction struct.
        require(_startingPrice == uint256(uint128(_startingPrice)));
        require(_endingPrice == uint256(uint128(_endingPrice)));
        require(_duration == uint256(uint64(_duration)));

        require(_owns(msg.sender, _tokenId));
        _escrow(msg.sender, _tokenId);
        Auction memory auction = Auction(
            _seller,
            uint128(_startingPrice),
            uint128(_endingPrice),
            uint64(_duration),
            uint64(now)
        );
        _addAuction(_tokenId, auction);
    }

    /// @dev Bids on an open auction, completing the auction and transferring
    ///  ownership of the NFT if enough Ether is supplied.
    /// @param _tokenId - ID of token to bid on.
    function bid(uint256 _tokenId)
        external
        payable
        whenNotPaused
    {
        // _bid will throw if the bid or funds transfer fails
        _bid(_tokenId, msg.value);
        _transfer(msg.sender, _tokenId);
    }

    /// @dev Cancels an auction that hasn't been won yet.
    ///  Returns the NFT to original owner.
    /// @notice This is a state-modifying function that can
    ///  be called while the contract is paused.
    /// @param _tokenId - ID of token on auction
    function cancelAuction(uint256 _tokenId)
        external
    {
        Auction storage auction = tokenIdToAuction[_tokenId];
        require(_isOnAuction(auction));
        address seller = auction.seller;
        require(msg.sender == seller);
        _cancelAuction(_tokenId, seller);
    }

    /// @dev Cancels an auction when the contract is paused.
    ///  Only the owner may do this, and NFTs are returned to
    ///  the seller. This should only be used in emergencies.
    /// @param _tokenId - ID of the NFT on auction to cancel.
    function cancelAuctionWhenPaused(uint256 _tokenId)
        whenPaused
        onlyOwner
        external
    {
        Auction storage auction = tokenIdToAuction[_tokenId];
        require(_isOnAuction(auction));
        _cancelAuction(_tokenId, auction.seller);
    }

    /// @dev Returns auction info for an NFT on auction.
    /// @param _tokenId - ID of NFT on auction.
    function getAuction(uint256 _tokenId)
        external
        view
        returns
    (
        address seller,
        uint256 startingPrice,
        uint256 endingPrice,
        uint256 duration,
        uint256 startedAt
    ) {
        Auction storage auction = tokenIdToAuction[_tokenId];
        require(_isOnAuction(auction));
        return (
            auction.seller,
            auction.startingPrice,
            auction.endingPrice,
            auction.duration,
            auction.startedAt
        );
    }

    /// @dev Returns the current price of an auction.
    /// @param _tokenId - ID of the token price we are checking.
    function getCurrentPrice(uint256 _tokenId)
        external
        view
        returns (uint256)
    {
        Auction storage auction = tokenIdToAuction[_tokenId];
        require(_isOnAuction(auction));
        return _currentPrice(auction);
    }

}


/// @title Clock auction modified for sale of kitties
/// @notice We omit a fallback function to prevent accidental sends to this contract.
contract SaleClockAuction is ClockAuction {

    // @dev Sanity check that allows us to ensure that we are pointing to the
    //  right auction in our setSaleAuctionAddress() call.
    bool public isSaleClockAuction = true;
    
    // Tracks last 5 sale price of gen0 kitty sales
    uint256 public gen0SaleCount;
    uint256[5] public lastGen0SalePrices;

    // Delegate constructor
    function SaleClockAuction(address _nftAddr, uint256 _cut) public
        ClockAuction(_nftAddr, _cut) {}

    /// @dev Creates and begins a new auction.
    /// @param _tokenId - ID of token to auction, sender must be owner.
    /// @param _startingPrice - Price of item (in wei) at beginning of auction.
    /// @param _endingPrice - Price of item (in wei) at end of auction.
    /// @param _duration - Length of auction (in seconds).
    /// @param _seller - Seller, if not the message sender
    function createAuction(
        uint256 _tokenId,
        uint256 _startingPrice,
        uint256 _endingPrice,
        uint256 _duration,
        address _seller
    )
        external
    {
        // Sanity check that no inputs overflow how many bits we've allocated
        // to store them in the auction struct.
        require(_startingPrice == uint256(uint128(_startingPrice)));
        require(_endingPrice == uint256(uint128(_endingPrice)));
        require(_duration == uint256(uint64(_duration)));

        require(msg.sender == address(nonFungibleContract));
        _escrow(_seller, _tokenId);
        Auction memory auction = Auction(
            _seller,
            uint128(_startingPrice),
            uint128(_endingPrice),
            uint64(_duration),
            uint64(now)
        );
        _addAuction(_tokenId, auction);
    }

    /// @dev Updates lastSalePrice if seller is the nft contract
    /// Otherwise, works the same as default bid method.
    function bid(uint256 _tokenId)
        external
        payable
    {
        // _bid verifies token ID size
        address seller = tokenIdToAuction[_tokenId].seller;
        uint256 price = _bid(_tokenId, msg.value);
        _transfer(msg.sender, _tokenId);

        // If not a gen0 auction, exit
        if (seller == address(nonFungibleContract)) {
            // Track gen0 sale prices
            lastGen0SalePrices[gen0SaleCount % 5] = price;
            gen0SaleCount++;
        }
    }

    function averageGen0SalePrice() external view returns (uint256) {
        uint256 sum = 0;
        for (uint256 i = 0; i < 5; i++) {
            sum += lastGen0SalePrices[i];
        }
        return sum / 5;
    }

}

pragma solidity ^0.4.11;


/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
  address public owner;


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  function Ownable() {
    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) onlyOwner {
    if (newOwner != address(0)) {
      owner = newOwner;
    }
  }

}



/// @title Interface for contracts conforming to ERC-721: Non-Fungible Tokens
/// @author Dieter Shirley <[email protected]> (https://github.com/dete)
contract ERC721 {
    // Required methods
    function totalSupply() public view returns (uint256 total);
    function balanceOf(address _owner) public view returns (uint256 balance);
    function ownerOf(uint256 _tokenId) external view returns (address owner);
    function approve(address _to, uint256 _tokenId) external;
    function transfer(address _to, uint256 _tokenId) external;
    function transferFrom(address _from, address _to, uint256 _tokenId) external;

    // Events
    event Transfer(address from, address to, uint256 tokenId);
    event Approval(address owner, address approved, uint256 tokenId);

    // Optional
    // function name() public view returns (string name);
    // function symbol() public view returns (string symbol);
    // function tokensOfOwner(address _owner) external view returns (uint256[] tokenIds);
    // function tokenMetadata(uint256 _tokenId, string _preferredTransport) public view returns (string infoUrl);

    // ERC-165 Compatibility (https://github.com/ethereum/EIPs/issues/165)
    function supportsInterface(bytes4 _interfaceID) external view returns (bool);
}


// // Auction wrapper functions


// Auction wrapper functions







/// @title SEKRETOOOO
contract GeneScienceInterface {
    /// @dev simply a boolean to indicate this is the contract we expect to be
    function isGeneScience() public pure returns (bool);

    /// @dev given genes of kitten 1 & 2, return a genetic combination - may have a random factor
    /// @param genes1 genes of mom
    /// @param genes2 genes of sire
    /// @return the genes that are supposed to be passed down the child
    function mixGenes(uint256 genes1, uint256 genes2, uint256 targetBlock) public returns (uint256);
}







/// @title A facet of KittyCore that manages special access privileges.
/// @author Axiom Zen (https://www.axiomzen.co)
/// @dev See the KittyCore contract documentation to understand how the various contract facets are arranged.
contract KittyAccessControl {
    // This facet controls access control for CryptoKitties. There are four roles managed here:
    //
    //     - The CEO: The CEO can reassign other roles and change the addresses of our dependent smart
    //         contracts. It is also the only role that can unpause the smart contract. It is initially
    //         set to the address that created the smart contract in the KittyCore constructor.
    //
    //     - The CFO: The CFO can withdraw funds from KittyCore and its auction contracts.
    //
    //     - The COO: The COO can release gen0 kitties to auction, and mint promo cats.
    //
    // It should be noted that these roles are distinct without overlap in their access abilities, the
    // abilities listed for each role above are exhaustive. In particular, while the CEO can assign any
    // address to any role, the CEO address itself doesn't have the ability to act in those roles. This
    // restriction is intentional so that we aren't tempted to use the CEO address frequently out of
    // convenience. The less we use an address, the less likely it is that we somehow compromise the
    // account.

    /// @dev Emited when contract is upgraded - See README.md for updgrade plan
    event ContractUpgrade(address newContract);

    // The addresses of the accounts (or contracts) that can execute actions within each roles.
    address public ceoAddress;
    address public cfoAddress;
    address public cooAddress;

    // @dev Keeps track whether the contract is paused. When that is true, most actions are blocked
    bool public paused = false;

    /// @dev Access modifier for CEO-only functionality
    modifier onlyCEO() {
        require(msg.sender == ceoAddress);
        _;
    }

    /// @dev Access modifier for CFO-only functionality
    modifier onlyCFO() {
        require(msg.sender == cfoAddress);
        _;
    }

    /// @dev Access modifier for COO-only functionality
    modifier onlyCOO() {
        require(msg.sender == cooAddress);
        _;
    }

    modifier onlyCLevel() {
        require(
            msg.sender == cooAddress ||
            msg.sender == ceoAddress ||
            msg.sender == cfoAddress
        );
        _;
    }

    /// @dev Assigns a new address to act as the CEO. Only available to the current CEO.
    /// @param _newCEO The address of the new CEO
    function setCEO(address _newCEO) external onlyCEO {
        require(_newCEO != address(0));

        ceoAddress = _newCEO;
    }

    /// @dev Assigns a new address to act as the CFO. Only available to the current CEO.
    /// @param _newCFO The address of the new CFO
    function setCFO(address _newCFO) external onlyCEO {
        require(_newCFO != address(0));

        cfoAddress = _newCFO;
    }

    /// @dev Assigns a new address to act as the COO. Only available to the current CEO.
    /// @param _newCOO The address of the new COO
    function setCOO(address _newCOO) external onlyCEO {
        require(_newCOO != address(0));

        cooAddress = _newCOO;
    }

    /*** Pausable functionality adapted from OpenZeppelin ***/

    /// @dev Modifier to allow actions only when the contract IS NOT paused
    modifier whenNotPaused() {
        require(!paused);
        _;
    }

    /// @dev Modifier to allow actions only when the contract IS paused
    modifier whenPaused {
        require(paused);
        _;
    }

    /// @dev Called by any "C-level" role to pause the contract. Used only when
    ///  a bug or exploit is detected and we need to limit damage.
    function pause() external onlyCLevel whenNotPaused {
        paused = true;
    }

    /// @dev Unpauses the smart contract. Can only be called by the CEO, since
    ///  one reason we may pause the contract is when CFO or COO accounts are
    ///  compromised.
    /// @notice This is public rather than external so it can be called by
    ///  derived contracts.
    function unpause() public onlyCEO whenPaused {
        // can't unpause if contract was upgraded
        paused = false;
    }
}




/// @title Base contract for CryptoKitties. Holds all common structs, events and base variables.
/// @author Axiom Zen (https://www.axiomzen.co)
/// @dev See the KittyCore contract documentation to understand how the various contract facets are arranged.
contract KittyBase is KittyAccessControl {
    /*** EVENTS ***/

    /// @dev The Birth event is fired whenever a new kitten comes into existence. This obviously
    ///  includes any time a cat is created through the giveBirth method, but it is also called
    ///  when a new gen0 cat is created.
    event Birth(address owner, uint256 kittyId, uint256 matronId, uint256 sireId, uint256 genes);

    /// @dev Transfer event as defined in current draft of ERC721. Emitted every time a kitten
    ///  ownership is assigned, including births.
    event Transfer(address from, address to, uint256 tokenId);

    /*** DATA TYPES ***/

    /// @dev The main Kitty struct. Every cat in CryptoKitties is represented by a copy
    ///  of this structure, so great care was taken to ensure that it fits neatly into
    ///  exactly two 256-bit words. Note that the order of the members in this structure
    ///  is important because of the byte-packing rules used by Ethereum.
    ///  Ref: http://solidity.readthedocs.io/en/develop/miscellaneous.html
    struct Kitty {
        // The Kitty's genetic code is packed into these 256-bits, the format is
        // sooper-sekret! A cat's genes never change.
        uint256 genes;

        // The timestamp from the block when this cat came into existence.
        uint64 birthTime;

        // The minimum timestamp after which this cat can engage in breeding
        // activities again. This same timestamp is used for the pregnancy
        // timer (for matrons) as well as the siring cooldown.
        uint64 cooldownEndBlock;

        // The ID of the parents of this kitty, set to 0 for gen0 cats.
        // Note that using 32-bit unsigned integers limits us to a "mere"
        // 4 billion cats. This number might seem small until you realize
        // that Ethereum currently has a limit of about 500 million
        // transactions per year! So, this definitely won't be a problem
        // for several years (even as Ethereum learns to scale).
        uint32 matronId;
        uint32 sireId;

        // Set to the ID of the sire cat for matrons that are pregnant,
        // zero otherwise. A non-zero value here is how we know a cat
        // is pregnant. Used to retrieve the genetic material for the new
        // kitten when the birth transpires.
        uint32 siringWithId;

        // Set to the index in the cooldown array (see below) that represents
        // the current cooldown duration for this Kitty. This starts at zero
        // for gen0 cats, and is initialized to floor(generation/2) for others.
        // Incremented by one for each successful breeding action, regardless
        // of whether this cat is acting as matron or sire.
        uint16 cooldownIndex;

        // The "generation number" of this cat. Cats minted by the CK contract
        // for sale are called "gen0" and have a generation number of 0. The
        // generation number of all other cats is the larger of the two generation
        // numbers of their parents, plus one.
        // (i.e. max(matron.generation, sire.generation) + 1)
        uint16 generation;
    }

    /*** CONSTANTS ***/

    /// @dev A lookup table indicating the cooldown duration after any successful
    ///  breeding action, called "pregnancy time" for matrons and "siring cooldown"
    ///  for sires. Designed such that the cooldown roughly doubles each time a cat
    ///  is bred, encouraging owners not to just keep breeding the same cat over
    ///  and over again. Caps out at one week (a cat can breed an unbounded number
    ///  of times, and the maximum cooldown is always seven days).
    uint32[14] public cooldowns = [
        uint32(1 minutes),
        uint32(2 minutes),
        uint32(5 minutes),
        uint32(10 minutes),
        uint32(30 minutes),
        uint32(1 hours),
        uint32(2 hours),
        uint32(4 hours),
        uint32(8 hours),
        uint32(16 hours),
        uint32(1 days),
        uint32(2 days),
        uint32(4 days),
        uint32(7 days)
    ];

    // An approximation of currently how many seconds are in between blocks.
    uint256 public secondsPerBlock = 15;

    /*** STORAGE ***/

    /// @dev An array containing the Kitty struct for all Kitties in existence. The ID
    ///  of each cat is actually an index into this array. Note that ID 0 is a negacat,
    ///  the unKitty, the mythical beast that is the parent of all gen0 cats. A bizarre
    ///  creature that is both matron and sire... to itself! Has an invalid genetic code.
    ///  In other words, cat ID 0 is invalid... ;-)
    Kitty[] kitties;

    /// @dev A mapping from cat IDs to the address that owns them. All cats have
    ///  some valid owner address, even gen0 cats are created with a non-zero owner.
    mapping (uint256 => address) public kittyIndexToOwner;

    // @dev A mapping from owner address to count of tokens that address owns.
    //  Used internally inside balanceOf() to resolve ownership count.
    mapping (address => uint256) ownershipTokenCount;

    /// @dev A mapping from KittyIDs to an address that has been approved to call
    ///  transferFrom(). Each Kitty can only have one approved address for transfer
    ///  at any time. A zero value means no approval is outstanding.
    mapping (uint256 => address) public kittyIndexToApproved;

    /// @dev A mapping from KittyIDs to an address that has been approved to use
    ///  this Kitty for siring via breedWith(). Each Kitty can only have one approved
    ///  address for siring at any time. A zero value means no approval is outstanding.
    mapping (uint256 => address) public sireAllowedToAddress;

    /// @dev The address of the ClockAuction contract that handles sales of Kitties. This
    ///  same contract handles both peer-to-peer sales as well as the gen0 sales which are
    ///  initiated every 15 minutes.
    SaleClockAuction public saleAuction;

    /// @dev The address of a custom ClockAuction subclassed contract that handles siring
    ///  auctions. Needs to be separate from saleAuction because the actions taken on success
    ///  after a sales and siring auction are quite different.
    SiringClockAuction public siringAuction;

    /// @dev Assigns ownership of a specific Kitty to an address.
    function _transfer(address _from, address _to, uint256 _tokenId) internal {
        // Since the number of kittens is capped to 2^32 we can't overflow this
        ownershipTokenCount[_to]++;
        // transfer ownership
        kittyIndexToOwner[_tokenId] = _to;
        // When creating new kittens _from is 0x0, but we can't account that address.
        if (_from != address(0)) {
            ownershipTokenCount[_from]--;
            // once the kitten is transferred also clear sire allowances
            delete sireAllowedToAddress[_tokenId];
            // clear any previously approved ownership exchange
            delete kittyIndexToApproved[_tokenId];
        }
        // Emit the transfer event.
        Transfer(_from, _to, _tokenId);
    }

    /// @dev An internal method that creates a new kitty and stores it. This
    ///  method doesn't do any checking and should only be called when the
    ///  input data is known to be valid. Will generate both a Birth event
    ///  and a Transfer event.
    /// @param _matronId The kitty ID of the matron of this cat (zero for gen0)
    /// @param _sireId The kitty ID of the sire of this cat (zero for gen0)
    /// @param _generation The generation number of this cat, must be computed by caller.
    /// @param _genes The kitty's genetic code.
    /// @param _owner The inital owner of this cat, must be non-zero (except for the unKitty, ID 0)
    function _createKitty(
        uint256 _matronId,
        uint256 _sireId,
        uint256 _generation,
        uint256 _genes,
        address _owner
    )
        internal
        returns (uint)
    {
        // These requires are not strictly necessary, our calling code should make
        // sure that these conditions are never broken. However! _createKitty() is already
        // an expensive call (for storage), and it doesn't hurt to be especially careful
        // to ensure our data structures are always valid.
        require(_matronId == uint256(uint32(_matronId)));
        require(_sireId == uint256(uint32(_sireId)));
        require(_generation == uint256(uint16(_generation)));

        // New kitty starts with the same cooldown as parent gen/2
        uint16 cooldownIndex = uint16(_generation / 2);
        if (cooldownIndex > 13) {
            cooldownIndex = 13;
        }

        Kitty memory _kitty = Kitty({
            genes: _genes,
            birthTime: uint64(now),
            cooldownEndBlock: 0,
            matronId: uint32(_matronId),
            sireId: uint32(_sireId),
            siringWithId: 0,
            cooldownIndex: cooldownIndex,
            generation: uint16(_generation)
        });
        uint256 newKittenId = kitties.push(_kitty) - 1;

        // It's probably never going to happen, 4 billion cats is A LOT, but
        // let's just be 100% sure we never let this happen.
        require(newKittenId == uint256(uint32(newKittenId)));

        // emit the birth event
        Birth(
            _owner,
            newKittenId,
            uint256(_kitty.matronId),
            uint256(_kitty.sireId),
            _kitty.genes
        );

        // This will assign ownership, and also emit the Transfer event as
        // per ERC721 draft
        _transfer(0, _owner, newKittenId);

        return newKittenId;
    }

    // Any C-level can fix how many seconds per blocks are currently observed.
    function setSecondsPerBlock(uint256 secs) external onlyCLevel {
        require(secs < cooldowns[0]);
        secondsPerBlock = secs;
    }
}





/// @title The external contract that is responsible for generating metadata for the kitties,
///  it has one function that will return the data as bytes.
contract ERC721Metadata {
    /// @dev Given a token Id, returns a byte array that is supposed to be converted into string.
    function getMetadata(uint256 _tokenId, string) public view returns (bytes32[4] buffer, uint256 count) {
        if (_tokenId == 1) {
            buffer[0] = "Hello World! :D";
            count = 15;
        } else if (_tokenId == 2) {
            buffer[0] = "I would definitely choose a medi";
            buffer[1] = "um length string.";
            count = 49;
        } else if (_tokenId == 3) {
            buffer[0] = "Lorem ipsum dolor sit amet, mi e";
            buffer[1] = "st accumsan dapibus augue lorem,";
            buffer[2] = " tristique vestibulum id, libero";
            buffer[3] = " suscipit varius sapien aliquam.";
            count = 128;
        }
    }
}


/// @title The facet of the CryptoKitties core contract that manages ownership, ERC-721 (draft) compliant.
/// @author Axiom Zen (https://www.axiomzen.co)
/// @dev Ref: https://github.com/ethereum/EIPs/issues/721
///  See the KittyCore contract documentation to understand how the various contract facets are arranged.
contract KittyOwnership is KittyBase, ERC721 {

    /// @notice Name and symbol of the non fungible token, as defined in ERC721.
    string public constant name = "CryptoKitties";
    string public constant symbol = "CK";

    // The contract that will return kitty metadata
    ERC721Metadata public erc721Metadata;

    bytes4 constant InterfaceSignature_ERC165 =
        bytes4(keccak256('supportsInterface(bytes4)'));

    bytes4 constant InterfaceSignature_ERC721 =
        bytes4(keccak256('name()')) ^
        bytes4(keccak256('symbol()')) ^
        bytes4(keccak256('totalSupply()')) ^
        bytes4(keccak256('balanceOf(address)')) ^
        bytes4(keccak256('ownerOf(uint256)')) ^
        bytes4(keccak256('approve(address,uint256)')) ^
        bytes4(keccak256('transfer(address,uint256)')) ^
        bytes4(keccak256('transferFrom(address,address,uint256)')) ^
        bytes4(keccak256('tokensOfOwner(address)')) ^
        bytes4(keccak256('tokenMetadata(uint256,string)'));

    /// @notice Introspection interface as per ERC-165 (https://github.com/ethereum/EIPs/issues/165).
    ///  Returns true for any standardized interfaces implemented by this contract. We implement
    ///  ERC-165 (obviously!) and ERC-721.
    function supportsInterface(bytes4 _interfaceID) external view returns (bool)
    {
        // DEBUG ONLY
        //require((InterfaceSignature_ERC165 == 0x01ffc9a7) && (InterfaceSignature_ERC721 == 0x9a20483d));

        return ((_interfaceID == InterfaceSignature_ERC165) || (_interfaceID == InterfaceSignature_ERC721));
    }

    /// @dev Set the address of the sibling contract that tracks metadata.
    ///  CEO only.
    function setMetadataAddress(address _contractAddress) public onlyCEO {
        erc721Metadata = ERC721Metadata(_contractAddress);
    }

    // Internal utility functions: These functions all assume that their input arguments
    // are valid. We leave it to public methods to sanitize their inputs and follow
    // the required logic.

    /// @dev Checks if a given address is the current owner of a particular Kitty.
    /// @param _claimant the address we are validating against.
    /// @param _tokenId kitten id, only valid when > 0
    function _owns(address _claimant, uint256 _tokenId) internal view returns (bool) {
        return kittyIndexToOwner[_tokenId] == _claimant;
    }

    /// @dev Checks if a given address currently has transferApproval for a particular Kitty.
    /// @param _claimant the address we are confirming kitten is approved for.
    /// @param _tokenId kitten id, only valid when > 0
    function _approvedFor(address _claimant, uint256 _tokenId) internal view returns (bool) {
        return kittyIndexToApproved[_tokenId] == _claimant;
    }

    /// @dev Marks an address as being approved for transferFrom(), overwriting any previous
    ///  approval. Setting _approved to address(0) clears all transfer approval.
    ///  NOTE: _approve() does NOT send the Approval event. This is intentional because
    ///  _approve() and transferFrom() are used together for putting Kitties on auction, and
    ///  there is no value in spamming the log with Approval events in that case.
    function _approve(uint256 _tokenId, address _approved) internal {
        kittyIndexToApproved[_tokenId] = _approved;
    }

    /// @notice Returns the number of Kitties owned by a specific address.
    /// @param _owner The owner address to check.
    /// @dev Required for ERC-721 compliance
    function balanceOf(address _owner) public view returns (uint256 count) {
        return ownershipTokenCount[_owner];
    }

    /// @notice Transfers a Kitty to another address. If transferring to a smart
    ///  contract be VERY CAREFUL to ensure that it is aware of ERC-721 (or
    ///  CryptoKitties specifically) or your Kitty may be lost forever. Seriously.
    /// @param _to The address of the recipient, can be a user or contract.
    /// @param _tokenId The ID of the Kitty to transfer.
    /// @dev Required for ERC-721 compliance.
    function transfer(
        address _to,
        uint256 _tokenId
    )
        external
        whenNotPaused
    {
        // Safety check to prevent against an unexpected 0x0 default.
        require(_to != address(0));
        // Disallow transfers to this contract to prevent accidental misuse.
        // The contract should never own any kitties (except very briefly
        // after a gen0 cat is created and before it goes on auction).
        require(_to != address(this));
        // Disallow transfers to the auction contracts to prevent accidental
        // misuse. Auction contracts should only take ownership of kitties
        // through the allow + transferFrom flow.
        require(_to != address(saleAuction));
        require(_to != address(siringAuction));

        // You can only send your own cat.
        require(_owns(msg.sender, _tokenId));

        // Reassign ownership, clear pending approvals, emit Transfer event.
        _transfer(msg.sender, _to, _tokenId);
    }

    /// @notice Grant another address the right to transfer a specific Kitty via
    ///  transferFrom(). This is the preferred flow for transfering NFTs to contracts.
    /// @param _to The address to be granted transfer approval. Pass address(0) to
    ///  clear all approvals.
    /// @param _tokenId The ID of the Kitty that can be transferred if this call succeeds.
    /// @dev Required for ERC-721 compliance.
    function approve(
        address _to,
        uint256 _tokenId
    )
        external
        whenNotPaused
    {
        // Only an owner can grant transfer approval.
        require(_owns(msg.sender, _tokenId));

        // Register the approval (replacing any previous approval).
        _approve(_tokenId, _to);

        // Emit approval event.
        Approval(msg.sender, _to, _tokenId);
    }

    /// @notice Transfer a Kitty owned by another address, for which the calling address
    ///  has previously been granted transfer approval by the owner.
    /// @param _from The address that owns the Kitty to be transfered.
    /// @param _to The address that should take ownership of the Kitty. Can be any address,
    ///  including the caller.
    /// @param _tokenId The ID of the Kitty to be transferred.
    /// @dev Required for ERC-721 compliance.
    function transferFrom(
        address _from,
        address _to,
        uint256 _tokenId
    )
        external
        whenNotPaused
    {
        // Safety check to prevent against an unexpected 0x0 default.
        require(_to != address(0));
        // Disallow transfers to this contract to prevent accidental misuse.
        // The contract should never own any kitties (except very briefly
        // after a gen0 cat is created and before it goes on auction).
        require(_to != address(this));
        // Check for approval and valid ownership
        require(_approvedFor(msg.sender, _tokenId));
        require(_owns(_from, _tokenId));

        // Reassign ownership (also clears pending approvals and emits Transfer event).
        _transfer(_from, _to, _tokenId);
    }

    /// @notice Returns the total number of Kitties currently in existence.
    /// @dev Required for ERC-721 compliance.
    function totalSupply() public view returns (uint) {
        return kitties.length - 1;
    }

    /// @notice Returns the address currently assigned ownership of a given Kitty.
    /// @dev Required for ERC-721 compliance.
    function ownerOf(uint256 _tokenId)
        external
        view
        returns (address owner)
    {
        owner = kittyIndexToOwner[_tokenId];

        require(owner != address(0));
    }

    /// @notice Returns a list of all Kitty IDs assigned to an address.
    /// @param _owner The owner whose Kitties we are interested in.
    /// @dev This method MUST NEVER be called by smart contract code. First, it's fairly
    ///  expensive (it walks the entire Kitty array looking for cats belonging to owner),
    ///  but it also returns a dynamic array, which is only supported for web3 calls, and
    ///  not contract-to-contract calls.
    function tokensOfOwner(address _owner) external view returns(uint256[] ownerTokens) {
        uint256 tokenCount = balanceOf(_owner);

        if (tokenCount == 0) {
            // Return an empty array
            return new uint256[](0);
        } else {
            uint256[] memory result = new uint256[](tokenCount);
            uint256 totalCats = totalSupply();
            uint256 resultIndex = 0;

            // We count on the fact that all cats have IDs starting at 1 and increasing
            // sequentially up to the totalCat count.
            uint256 catId;

            for (catId = 1; catId <= totalCats; catId++) {
                if (kittyIndexToOwner[catId] == _owner) {
                    result[resultIndex] = catId;
                    resultIndex++;
                }
            }

            return result;
        }
    }

    /// @dev Adapted from memcpy() by @arachnid (Nick Johnson <[email protected]>)
    ///  This method is licenced under the Apache License.
    ///  Ref: https://github.com/Arachnid/solidity-stringutils/blob/2f6ca9accb48ae14c66f1437ec50ed19a0616f78/strings.sol
    function _memcpy(uint _dest, uint _src, uint _len) private view {
        // Copy word-length chunks while possible
        for(; _len >= 32; _len -= 32) {
            assembly {
                mstore(_dest, mload(_src))
            }
            _dest += 32;
            _src += 32;
        }

        // Copy remaining bytes
        uint256 mask = 256 ** (32 - _len) - 1;
        assembly {
            let srcpart := and(mload(_src), not(mask))
            let destpart := and(mload(_dest), mask)
            mstore(_dest, or(destpart, srcpart))
        }
    }

    /// @dev Adapted from toString(slice) by @arachnid (Nick Johnson <[email protected]>)
    ///  This method is licenced under the Apache License.
    ///  Ref: https://github.com/Arachnid/solidity-stringutils/blob/2f6ca9accb48ae14c66f1437ec50ed19a0616f78/strings.sol
    function _toString(bytes32[4] _rawBytes, uint256 _stringLength) private view returns (string) {
        var outputString = new string(_stringLength);
        uint256 outputPtr;
        uint256 bytesPtr;

        assembly {
            outputPtr := add(outputString, 32)
            bytesPtr := _rawBytes
        }

        _memcpy(outputPtr, bytesPtr, _stringLength);

        return outputString;
    }

    /// @notice Returns a URI pointing to a metadata package for this token conforming to
    ///  ERC-721 (https://github.com/ethereum/EIPs/issues/721)
    /// @param _tokenId The ID number of the Kitty whose metadata should be returned.
    function tokenMetadata(uint256 _tokenId, string _preferredTransport) external view returns (string infoUrl) {
        require(erc721Metadata != address(0));
        bytes32[4] memory buffer;
        uint256 count;
        (buffer, count) = erc721Metadata.getMetadata(_tokenId, _preferredTransport);

        return _toString(buffer, count);
    }
}



/// @title A facet of KittyCore that manages Kitty siring, gestation, and birth.
/// @author Axiom Zen (https://www.axiomzen.co)
/// @dev See the KittyCore contract documentation to understand how the various contract facets are arranged.
contract KittyBreeding is KittyOwnership {

    /// @dev The Pregnant event is fired when two cats successfully breed and the pregnancy
    ///  timer begins for the matron.
    event Pregnant(address owner, uint256 matronId, uint256 sireId, uint256 cooldownEndBlock);

    /// @notice The minimum payment required to use breedWithAuto(). This fee goes towards
    ///  the gas cost paid by whatever calls giveBirth(), and can be dynamically updated by
    ///  the COO role as the gas price changes.
    uint256 public autoBirthFee = 2 finney;

    // Keeps track of number of pregnant kitties.
    uint256 public pregnantKitties;

    /// @dev The address of the sibling contract that is used to implement the sooper-sekret
    ///  genetic combination algorithm.
    GeneScienceInterface public geneScience;

    /// @dev Update the address of the genetic contract, can only be called by the CEO.
    /// @param _address An address of a GeneScience contract instance to be used from this point forward.
    function setGeneScienceAddress(address _address) external onlyCEO {
        GeneScienceInterface candidateContract = GeneScienceInterface(_address);

        // NOTE: verify that a contract is what we expect - https://github.com/Lunyr/crowdsale-contracts/blob/cfadd15986c30521d8ba7d5b6f57b4fefcc7ac38/contracts/LunyrToken.sol#L117
        require(candidateContract.isGeneScience());

        // Set the new contract address
        geneScience = candidateContract;
    }

    /// @dev Checks that a given kitten is able to breed. Requires that the
    ///  current cooldown is finished (for sires) and also checks that there is
    ///  no pending pregnancy.
    function _isReadyToBreed(Kitty _kit) internal view returns (bool) {
        // In addition to checking the cooldownEndBlock, we also need to check to see if
        // the cat has a pending birth; there can be some period of time between the end
        // of the pregnacy timer and the birth event.
        return (_kit.siringWithId == 0) && (_kit.cooldownEndBlock <= uint64(block.number));
    }

    /// @dev Check if a sire has authorized breeding with this matron. True if both sire
    ///  and matron have the same owner, or if the sire has given siring permission to
    ///  the matron's owner (via approveSiring()).
    function _isSiringPermitted(uint256 _sireId, uint256 _matronId) internal view returns (bool) {
        address matronOwner = kittyIndexToOwner[_matronId];
        address sireOwner = kittyIndexToOwner[_sireId];

        // Siring is okay if they have same owner, or if the matron's owner was given
        // permission to breed with this sire.
        return (matronOwner == sireOwner || sireAllowedToAddress[_sireId] == matronOwner);
    }

    /// @dev Set the cooldownEndTime for the given Kitty, based on its current cooldownIndex.
    ///  Also increments the cooldownIndex (unless it has hit the cap).
    /// @param _kitten A reference to the Kitty in storage which needs its timer started.
    function _triggerCooldown(Kitty storage _kitten) internal {
        // Compute an estimation of the cooldown time in blocks (based on current cooldownIndex).
        _kitten.cooldownEndBlock = uint64((cooldowns[_kitten.cooldownIndex]/secondsPerBlock) + block.number);

        // Increment the breeding count, clamping it at 13, which is the length of the
        // cooldowns array. We could check the array size dynamically, but hard-coding
        // this as a constant saves gas. Yay, Solidity!
        if (_kitten.cooldownIndex < 13) {
            _kitten.cooldownIndex += 1;
        }
    }

    /// @notice Grants approval to another user to sire with one of your Kitties.
    /// @param _addr The address that will be able to sire with your Kitty. Set to
    ///  address(0) to clear all siring approvals for this Kitty.
    /// @param _sireId A Kitty that you own that _addr will now be able to sire with.
    function approveSiring(address _addr, uint256 _sireId)
        external
        whenNotPaused
    {
        require(_owns(msg.sender, _sireId));
        sireAllowedToAddress[_sireId] = _addr;
    }

    /// @dev Updates the minimum payment required for calling giveBirthAuto(). Can only
    ///  be called by the COO address. (This fee is used to offset the gas cost incurred
    ///  by the autobirth daemon).
    function setAutoBirthFee(uint256 val) external onlyCOO {
        autoBirthFee = val;
    }

    /// @dev Checks to see if a given Kitty is pregnant and (if so) if the gestation
    ///  period has passed.
    function _isReadyToGiveBirth(Kitty _matron) private view returns (bool) {
        return (_matron.siringWithId != 0) && (_matron.cooldownEndBlock <= uint64(block.number));
    }

    /// @notice Checks that a given kitten is able to breed (i.e. it is not pregnant or
    ///  in the middle of a siring cooldown).
    /// @param _kittyId reference the id of the kitten, any user can inquire about it
    function isReadyToBreed(uint256 _kittyId)
        public
        view
        returns (bool)
    {
        require(_kittyId > 0);
        Kitty storage kit = kitties[_kittyId];
        return _isReadyToBreed(kit);
    }

    /// @dev Checks whether a kitty is currently pregnant.
    /// @param _kittyId reference the id of the kitten, any user can inquire about it
    function isPregnant(uint256 _kittyId)
        public
        view
        returns (bool)
    {
        require(_kittyId > 0);
        // A kitty is pregnant if and only if this field is set
        return kitties[_kittyId].siringWithId != 0;
    }

    /// @dev Internal check to see if a given sire and matron are a valid mating pair. DOES NOT
    ///  check ownership permissions (that is up to the caller).
    /// @param _matron A reference to the Kitty struct of the potential matron.
    /// @param _matronId The matron's ID.
    /// @param _sire A reference to the Kitty struct of the potential sire.
    /// @param _sireId The sire's ID
    function _isValidMatingPair(
        Kitty storage _matron,
        uint256 _matronId,
        Kitty storage _sire,
        uint256 _sireId
    )
        private
        view
        returns(bool)
    {
        // A Kitty can't breed with itself!
        if (_matronId == _sireId) {
            return false;
        }

        // Kitties can't breed with their parents.
        if (_matron.matronId == _sireId || _matron.sireId == _sireId) {
            return false;
        }
        if (_sire.matronId == _matronId || _sire.sireId == _matronId) {
            return false;
        }

        // We can short circuit the sibling check (below) if either cat is
        // gen zero (has a matron ID of zero).
        if (_sire.matronId == 0 || _matron.matronId == 0) {
            return true;
        }

        // Kitties can't breed with full or half siblings.
        if (_sire.matronId == _matron.matronId || _sire.matronId == _matron.sireId) {
            return false;
        }
        if (_sire.sireId == _matron.matronId || _sire.sireId == _matron.sireId) {
            return false;
        }

        // Everything seems cool! Let's get DTF.
        return true;
    }

    /// @dev Internal check to see if a given sire and matron are a valid mating pair for
    ///  breeding via auction (i.e. skips ownership and siring approval checks).
    function _canBreedWithViaAuction(uint256 _matronId, uint256 _sireId)
        internal
        view
        returns (bool)
    {
        Kitty storage matron = kitties[_matronId];
        Kitty storage sire = kitties[_sireId];
        return _isValidMatingPair(matron, _matronId, sire, _sireId);
    }

    /// @notice Checks to see if two cats can breed together, including checks for
    ///  ownership and siring approvals. Does NOT check that both cats are ready for
    ///  breeding (i.e. breedWith could still fail until the cooldowns are finished).
    ///  TODO: Shouldn't this check pregnancy and cooldowns?!?
    /// @param _matronId The ID of the proposed matron.
    /// @param _sireId The ID of the proposed sire.
    function canBreedWith(uint256 _matronId, uint256 _sireId)
        external
        view
        returns(bool)
    {
        require(_matronId > 0);
        require(_sireId > 0);
        Kitty storage matron = kitties[_matronId];
        Kitty storage sire = kitties[_sireId];
        return _isValidMatingPair(matron, _matronId, sire, _sireId) &&
            _isSiringPermitted(_sireId, _matronId);
    }

    /// @dev Internal utility function to initiate breeding, assumes that all breeding
    ///  requirements have been checked.
    function _breedWith(uint256 _matronId, uint256 _sireId) internal {
        // Grab a reference to the Kitties from storage.
        Kitty storage sire = kitties[_sireId];
        Kitty storage matron = kitties[_matronId];

        // Mark the matron as pregnant, keeping track of who the sire is.
        matron.siringWithId = uint32(_sireId);

        // Trigger the cooldown for both parents.
        _triggerCooldown(sire);
        _triggerCooldown(matron);

        // Clear siring permission for both parents. This may not be strictly necessary
        // but it's likely to avoid confusion!
        delete sireAllowedToAddress[_matronId];
        delete sireAllowedToAddress[_sireId];

        // Every time a kitty gets pregnant, counter is incremented.
        pregnantKitties++;

        // Emit the pregnancy event.
        Pregnant(kittyIndexToOwner[_matronId], _matronId, _sireId, matron.cooldownEndBlock);
    }

    /// @notice Breed a Kitty you own (as matron) with a sire that you own, or for which you
    ///  have previously been given Siring approval. Will either make your cat pregnant, or will
    ///  fail entirely. Requires a pre-payment of the fee given out to the first caller of giveBirth()
    /// @param _matronId The ID of the Kitty acting as matron (will end up pregnant if successful)
    /// @param _sireId The ID of the Kitty acting as sire (will begin its siring cooldown if successful)
    function breedWithAuto(uint256 _matronId, uint256 _sireId)
        external
        payable
        whenNotPaused
    {
        // Checks for payment.
        require(msg.value >= autoBirthFee);

        // Caller must own the matron.
        require(_owns(msg.sender, _matronId));

        // Neither sire nor matron are allowed to be on auction during a normal
        // breeding operation, but we don't need to check that explicitly.
        // For matron: The caller of this function can't be the owner of the matron
        //   because the owner of a Kitty on auction is the auction house, and the
        //   auction house will never call breedWith().
        // For sire: Similarly, a sire on auction will be owned by the auction house
        //   and the act of transferring ownership will have cleared any oustanding
        //   siring approval.
        // Thus we don't need to spend gas explicitly checking to see if either cat
        // is on auction.

        // Check that matron and sire are both owned by caller, or that the sire
        // has given siring permission to caller (i.e. matron's owner).
        // Will fail for _sireId = 0
        require(_isSiringPermitted(_sireId, _matronId));

        // Grab a reference to the potential matron
        Kitty storage matron = kitties[_matronId];

        // Make sure matron isn't pregnant, or in the middle of a siring cooldown
        require(_isReadyToBreed(matron));

        // Grab a reference to the potential sire
        Kitty storage sire = kitties[_sireId];

        // Make sure sire isn't pregnant, or in the middle of a siring cooldown
        require(_isReadyToBreed(sire));

        // Test that these cats are a valid mating pair.
        require(_isValidMatingPair(
            matron,
            _matronId,
            sire,
            _sireId
        ));

        // All checks passed, kitty gets pregnant!
        _breedWith(_matronId, _sireId);
    }

    /// @notice Have a pregnant Kitty give birth!
    /// @param _matronId A Kitty ready to give birth.
    /// @return The Kitty ID of the new kitten.
    /// @dev Looks at a given Kitty and, if pregnant and if the gestation period has passed,
    ///  combines the genes of the two parents to create a new kitten. The new Kitty is assigned
    ///  to the current owner of the matron. Upon successful completion, both the matron and the
    ///  new kitten will be ready to breed again. Note that anyone can call this function (if they
    ///  are willing to pay the gas!), but the new kitten always goes to the mother's owner.
    function giveBirth(uint256 _matronId)
        external
        whenNotPaused
        returns(uint256)
    {
        // Grab a reference to the matron in storage.
        Kitty storage matron = kitties[_matronId];

        // Check that the matron is a valid cat.
        require(matron.birthTime != 0);

        // Check that the matron is pregnant, and that its time has come!
        require(_isReadyToGiveBirth(matron));

        // Grab a reference to the sire in storage.
        uint256 sireId = matron.siringWithId;
        Kitty storage sire = kitties[sireId];

        // Determine the higher generation number of the two parents
        uint16 parentGen = matron.generation;
        if (sire.generation > matron.generation) {
            parentGen = sire.generation;
        }

        // Call the sooper-sekret gene mixing operation.
        uint256 childGenes = geneScience.mixGenes(matron.genes, sire.genes, matron.cooldownEndBlock - 1);

        // Make the new kitten!
        address owner = kittyIndexToOwner[_matronId];
        uint256 kittenId = _createKitty(_matronId, matron.siringWithId, parentGen + 1, childGenes, owner);

        // Clear the reference to sire from the matron (REQUIRED! Having siringWithId
        // set is what marks a matron as being pregnant.)
        delete matron.siringWithId;

        // Every time a kitty gives birth counter is decremented.
        pregnantKitties--;

        // Send the balance fee to the person who made birth happen.
        msg.sender.send(autoBirthFee);

        // return the new kitten's ID
        return kittenId;
    }
}










/// @title Auction Core
/// @dev Contains models, variables, and internal methods for the auction.
/// @notice We omit a fallback function to prevent accidental sends to this contract.
contract ClockAuctionBase {

    // Represents an auction on an NFT
    struct Auction {
        // Current owner of NFT
        address seller;
        // Price (in wei) at beginning of auction
        uint128 startingPrice;
        // Price (in wei) at end of auction
        uint128 endingPrice;
        // Duration (in seconds) of auction
        uint64 duration;
        // Time when auction started
        // NOTE: 0 if this auction has been concluded
        uint64 startedAt;
    }

    // Reference to contract tracking NFT ownership
    ERC721 public nonFungibleContract;

    // Cut owner takes on each auction, measured in basis points (1/100 of a percent).
    // Values 0-10,000 map to 0%-100%
    uint256 public ownerCut;

    // Map from token ID to their corresponding auction.
    mapping (uint256 => Auction) tokenIdToAuction;

    event AuctionCreated(uint256 tokenId, uint256 startingPrice, uint256 endingPrice, uint256 duration);
    event AuctionSuccessful(uint256 tokenId, uint256 totalPrice, address winner);
    event AuctionCancelled(uint256 tokenId);

    /// @dev Returns true if the claimant owns the token.
    /// @param _claimant - Address claiming to own the token.
    /// @param _tokenId - ID of token whose ownership to verify.
    function _owns(address _claimant, uint256 _tokenId) internal view returns (bool) {
        return (nonFungibleContract.ownerOf(_tokenId) == _claimant);
    }

    /// @dev Escrows the NFT, assigning ownership to this contract.
    /// Throws if the escrow fails.
    /// @param _owner - Current owner address of token to escrow.
    /// @param _tokenId - ID of token whose approval to verify.
    function _escrow(address _owner, uint256 _tokenId) internal {
        // it will throw if transfer fails
        nonFungibleContract.transferFrom(_owner, this, _tokenId);
    }

    /// @dev Transfers an NFT owned by this contract to another address.
    /// Returns true if the transfer succeeds.
    /// @param _receiver - Address to transfer NFT to.
    /// @param _tokenId - ID of token to transfer.
    function _transfer(address _receiver, uint256 _tokenId) internal {
        // it will throw if transfer fails
        nonFungibleContract.transfer(_receiver, _tokenId);
    }

    /// @dev Adds an auction to the list of open auctions. Also fires the
    ///  AuctionCreated event.
    /// @param _tokenId The ID of the token to be put on auction.
    /// @param _auction Auction to add.
    function _addAuction(uint256 _tokenId, Auction _auction) internal {
        // Require that all auctions have a duration of
        // at least one minute. (Keeps our math from getting hairy!)
        require(_auction.duration >= 1 minutes);

        tokenIdToAuction[_tokenId] = _auction;

        AuctionCreated(
            uint256(_tokenId),
            uint256(_auction.startingPrice),
            uint256(_auction.endingPrice),
            uint256(_auction.duration)
        );
    }

    /// @dev Cancels an auction unconditionally.
    function _cancelAuction(uint256 _tokenId, address _seller) internal {
        _removeAuction(_tokenId);
        _transfer(_seller, _tokenId);
        AuctionCancelled(_tokenId);
    }

    /// @dev Computes the price and transfers winnings.
    /// Does NOT transfer ownership of token.
    function _bid(uint256 _tokenId, uint256 _bidAmount)
        internal
        returns (uint256)
    {
        // Get a reference to the auction struct
        Auction storage auction = tokenIdToAuction[_tokenId];

        // Explicitly check that this auction is currently live.
        // (Because of how Ethereum mappings work, we can't just count
        // on the lookup above failing. An invalid _tokenId will just
        // return an auction object that is all zeros.)
        require(_isOnAuction(auction));

        // Check that the bid is greater than or equal to the current price
        uint256 price = _currentPrice(auction);
        require(_bidAmount >= price);

        // Grab a reference to the seller before the auction struct
        // gets deleted.
        address seller = auction.seller;

        // The bid is good! Remove the auction before sending the fees
        // to the sender so we can't have a reentrancy attack.
        _removeAuction(_tokenId);

        // Transfer proceeds to seller (if there are any!)
        if (price > 0) {
            // Calculate the auctioneer's cut.
            // (NOTE: _computeCut() is guaranteed to return a
            // value <= price, so this subtraction can't go negative.)
            uint256 auctioneerCut = _computeCut(price);
            uint256 sellerProceeds = price - auctioneerCut;

            // NOTE: Doing a transfer() in the middle of a complex
            // method like this is generally discouraged because of
            // reentrancy attacks and DoS attacks if the seller is
            // a contract with an invalid fallback function. We explicitly
            // guard against reentrancy attacks by removing the auction
            // before calling transfer(), and the only thing the seller
            // can DoS is the sale of their own asset! (And if it's an
            // accident, they can call cancelAuction(). )
            seller.transfer(sellerProceeds);
        }

        // Calculate any excess funds included with the bid. If the excess
        // is anything worth worrying about, transfer it back to bidder.
        // NOTE: We checked above that the bid amount is greater than or
        // equal to the price so this cannot underflow.
        uint256 bidExcess = _bidAmount - price;

        // Return the funds. Similar to the previous transfer, this is
        // not susceptible to a re-entry attack because the auction is
        // removed before any transfers occur.
        msg.sender.transfer(bidExcess);

        // Tell the world!
        AuctionSuccessful(_tokenId, price, msg.sender);

        return price;
    }

    /// @dev Removes an auction from the list of open auctions.
    /// @param _tokenId - ID of NFT on auction.
    function _removeAuction(uint256 _tokenId) internal {
        delete tokenIdToAuction[_tokenId];
    }

    /// @dev Returns true if the NFT is on auction.
    /// @param _auction - Auction to check.
    function _isOnAuction(Auction storage _auction) internal view returns (bool) {
        return (_auction.startedAt > 0);
    }

    /// @dev Returns current price of an NFT on auction. Broken into two
    ///  functions (this one, that computes the duration from the auction
    ///  structure, and the other that does the price computation) so we
    ///  can easily test that the price computation works correctly.
    function _currentPrice(Auction storage _auction)
        internal
        view
        returns (uint256)
    {
        uint256 secondsPassed = 0;

        // A bit of insurance against negative values (or wraparound).
        // Probably not necessary (since Ethereum guarnatees that the
        // now variable doesn't ever go backwards).
        if (now > _auction.startedAt) {
            secondsPassed = now - _auction.startedAt;
        }

        return _computeCurrentPrice(
            _auction.startingPrice,
            _auction.endingPrice,
            _auction.duration,
            secondsPassed
        );
    }

    /// @dev Computes the current price of an auction. Factored out
    ///  from _currentPrice so we can run extensive unit tests.
    ///  When testing, make this function public and turn on
    ///  `Current price computation` test suite.
    function _computeCurrentPrice(
        uint256 _startingPrice,
        uint256 _endingPrice,
        uint256 _duration,
        uint256 _secondsPassed
    )
        internal
        pure
        returns (uint256)
    {
        // NOTE: We don't use SafeMath (or similar) in this function because
        //  all of our public functions carefully cap the maximum values for
        //  time (at 64-bits) and currency (at 128-bits). _duration is
        //  also known to be non-zero (see the require() statement in
        //  _addAuction())
        if (_secondsPassed >= _duration) {
            // We've reached the end of the dynamic pricing portion
            // of the auction, just return the end price.
            return _endingPrice;
        } else {
            // Starting price can be higher than ending price (and often is!), so
            // this delta can be negative.
            int256 totalPriceChange = int256(_endingPrice) - int256(_startingPrice);

            // This multiplication can't overflow, _secondsPassed will easily fit within
            // 64-bits, and totalPriceChange will easily fit within 128-bits, their product
            // will always fit within 256-bits.
            int256 currentPriceChange = totalPriceChange * int256(_secondsPassed) / int256(_duration);

            // currentPriceChange can be negative, but if so, will have a magnitude
            // less that _startingPrice. Thus, this result will always end up positive.
            int256 currentPrice = int256(_startingPrice) + currentPriceChange;

            return uint256(currentPrice);
        }
    }

    /// @dev Computes owner's cut of a sale.
    /// @param _price - Sale price of NFT.
    function _computeCut(uint256 _price) internal view returns (uint256) {
        // NOTE: We don't use SafeMath (or similar) in this function because
        //  all of our entry functions carefully cap the maximum values for
        //  currency (at 128-bits), and ownerCut <= 10000 (see the require()
        //  statement in the ClockAuction constructor). The result of this
        //  function is always guaranteed to be <= _price.
        return _price * ownerCut / 10000;
    }

}







/**
 * @title Pausable
 * @dev Base contract which allows children to implement an emergency stop mechanism.
 */
contract Pausable is Ownable {
  event Pause();
  event Unpause();

  bool public paused = false;


  /**
   * @dev modifier to allow actions only when the contract IS paused
   */
  modifier whenNotPaused() {
    require(!paused);
    _;
  }

  /**
   * @dev modifier to allow actions only when the contract IS NOT paused
   */
  modifier whenPaused {
    require(paused);
    _;
  }

  /**
   * @dev called by the owner to pause, triggers stopped state
   */
  function pause() onlyOwner whenNotPaused returns (bool) {
    paused = true;
    Pause();
    return true;
  }

  /**
   * @dev called by the owner to unpause, returns to normal state
   */
  function unpause() onlyOwner whenPaused returns (bool) {
    paused = false;
    Unpause();
    return true;
  }
}


/// @title Clock auction for non-fungible tokens.
/// @notice We omit a fallback function to prevent accidental sends to this contract.
contract ClockAuction is Pausable, ClockAuctionBase {

    /// @dev The ERC-165 interface signature for ERC-721.
    ///  Ref: https://github.com/ethereum/EIPs/issues/165
    ///  Ref: https://github.com/ethereum/EIPs/issues/721
    bytes4 constant InterfaceSignature_ERC721 = bytes4(0x9a20483d);

    /// @dev Constructor creates a reference to the NFT ownership contract
    ///  and verifies the owner cut is in the valid range.
    /// @param _nftAddress - address of a deployed contract implementing
    ///  the Nonfungible Interface.
    /// @param _cut - percent cut the owner takes on each auction, must be
    ///  between 0-10,000.
    function ClockAuction(address _nftAddress, uint256 _cut) public {
        require(_cut <= 10000);
        ownerCut = _cut;

        ERC721 candidateContract = ERC721(_nftAddress);
        require(candidateContract.supportsInterface(InterfaceSignature_ERC721));
        nonFungibleContract = candidateContract;
    }

    /// @dev Remove all Ether from the contract, which is the owner's cuts
    ///  as well as any Ether sent directly to the contract address.
    ///  Always transfers to the NFT contract, but can be called either by
    ///  the owner or the NFT contract.
    function withdrawBalance() external {
        address nftAddress = address(nonFungibleContract);

        require(
            msg.sender == owner ||
            msg.sender == nftAddress
        );
        // We are using this boolean method to make sure that even if one fails it will still work
        bool res = nftAddress.send(this.balance);
    }

    /// @dev Creates and begins a new auction.
    /// @param _tokenId - ID of token to auction, sender must be owner.
    /// @param _startingPrice - Price of item (in wei) at beginning of auction.
    /// @param _endingPrice - Price of item (in wei) at end of auction.
    /// @param _duration - Length of time to move between starting
    ///  price and ending price (in seconds).
    /// @param _seller - Seller, if not the message sender
    function createAuction(
        uint256 _tokenId,
        uint256 _startingPrice,
        uint256 _endingPrice,
        uint256 _duration,
        address _seller
    )
        external
        whenNotPaused
    {
        // Sanity check that no inputs overflow how many bits we've allocated
        // to store them in the auction struct.
        require(_startingPrice == uint256(uint128(_startingPrice)));
        require(_endingPrice == uint256(uint128(_endingPrice)));
        require(_duration == uint256(uint64(_duration)));

        require(_owns(msg.sender, _tokenId));
        _escrow(msg.sender, _tokenId);
        Auction memory auction = Auction(
            _seller,
            uint128(_startingPrice),
            uint128(_endingPrice),
            uint64(_duration),
            uint64(now)
        );
        _addAuction(_tokenId, auction);
    }

    /// @dev Bids on an open auction, completing the auction and transferring
    ///  ownership of the NFT if enough Ether is supplied.
    /// @param _tokenId - ID of token to bid on.
    function bid(uint256 _tokenId)
        external
        payable
        whenNotPaused
    {
        // _bid will throw if the bid or funds transfer fails
        _bid(_tokenId, msg.value);
        _transfer(msg.sender, _tokenId);
    }

    /// @dev Cancels an auction that hasn't been won yet.
    ///  Returns the NFT to original owner.
    /// @notice This is a state-modifying function that can
    ///  be called while the contract is paused.
    /// @param _tokenId - ID of token on auction
    function cancelAuction(uint256 _tokenId)
        external
    {
        Auction storage auction = tokenIdToAuction[_tokenId];
        require(_isOnAuction(auction));
        address seller = auction.seller;
        require(msg.sender == seller);
        _cancelAuction(_tokenId, seller);
    }

    /// @dev Cancels an auction when the contract is paused.
    ///  Only the owner may do this, and NFTs are returned to
    ///  the seller. This should only be used in emergencies.
    /// @param _tokenId - ID of the NFT on auction to cancel.
    function cancelAuctionWhenPaused(uint256 _tokenId)
        whenPaused
        onlyOwner
        external
    {
        Auction storage auction = tokenIdToAuction[_tokenId];
        require(_isOnAuction(auction));
        _cancelAuction(_tokenId, auction.seller);
    }

    /// @dev Returns auction info for an NFT on auction.
    /// @param _tokenId - ID of NFT on auction.
    function getAuction(uint256 _tokenId)
        external
        view
        returns
    (
        address seller,
        uint256 startingPrice,
        uint256 endingPrice,
        uint256 duration,
        uint256 startedAt
    ) {
        Auction storage auction = tokenIdToAuction[_tokenId];
        require(_isOnAuction(auction));
        return (
            auction.seller,
            auction.startingPrice,
            auction.endingPrice,
            auction.duration,
            auction.startedAt
        );
    }

    /// @dev Returns the current price of an auction.
    /// @param _tokenId - ID of the token price we are checking.
    function getCurrentPrice(uint256 _tokenId)
        external
        view
        returns (uint256)
    {
        Auction storage auction = tokenIdToAuction[_tokenId];
        require(_isOnAuction(auction));
        return _currentPrice(auction);
    }

}


/// @title Reverse auction modified for siring
/// @notice We omit a fallback function to prevent accidental sends to this contract.
contract SiringClockAuction is ClockAuction {

    // @dev Sanity check that allows us to ensure that we are pointing to the
    //  right auction in our setSiringAuctionAddress() call.
    bool public isSiringClockAuction = true;

    // Delegate constructor
    function SiringClockAuction(address _nftAddr, uint256 _cut) public
        ClockAuction(_nftAddr, _cut) {}

    /// @dev Creates and begins a new auction. Since this function is wrapped,
    /// require sender to be KittyCore contract.
    /// @param _tokenId - ID of token to auction, sender must be owner.
    /// @param _startingPrice - Price of item (in wei) at beginning of auction.
    /// @param _endingPrice - Price of item (in wei) at end of auction.
    /// @param _duration - Length of auction (in seconds).
    /// @param _seller - Seller, if not the message sender
    function createAuction(
        uint256 _tokenId,
        uint256 _startingPrice,
        uint256 _endingPrice,
        uint256 _duration,
        address _seller
    )
        external
    {
        // Sanity check that no inputs overflow how many bits we've allocated
        // to store them in the auction struct.
        require(_startingPrice == uint256(uint128(_startingPrice)));
        require(_endingPrice == uint256(uint128(_endingPrice)));
        require(_duration == uint256(uint64(_duration)));

        require(msg.sender == address(nonFungibleContract));
        _escrow(_seller, _tokenId);
        Auction memory auction = Auction(
            _seller,
            uint128(_startingPrice),
            uint128(_endingPrice),
            uint64(_duration),
            uint64(now)
        );
        _addAuction(_tokenId, auction);
    }

    /// @dev Places a bid for siring. Requires the sender
    /// is the KittyCore contract because all bid methods
    /// should be wrapped. Also returns the kitty to the
    /// seller rather than the winner.
    function bid(uint256 _tokenId)
        external
        payable
    {
        require(msg.sender == address(nonFungibleContract));
        address seller = tokenIdToAuction[_tokenId].seller;
        // _bid checks that token ID is valid and will throw if bid fails
        _bid(_tokenId, msg.value);
        // We transfer the kitty back to the seller, the winner will get
        // the offspring
        _transfer(seller, _tokenId);
    }

}





/// @title Clock auction modified for sale of kitties
/// @notice We omit a fallback function to prevent accidental sends to this contract.
contract SaleClockAuction is ClockAuction {

    // @dev Sanity check that allows us to ensure that we are pointing to the
    //  right auction in our setSaleAuctionAddress() call.
    bool public isSaleClockAuction = true;

    // Tracks last 5 sale price of gen0 kitty sales
    uint256 public gen0SaleCount;
    uint256[5] public lastGen0SalePrices;

    // Delegate constructor
    function SaleClockAuction(address _nftAddr, uint256 _cut) public
        ClockAuction(_nftAddr, _cut) {}

    /// @dev Creates and begins a new auction.
    /// @param _tokenId - ID of token to auction, sender must be owner.
    /// @param _startingPrice - Price of item (in wei) at beginning of auction.
    /// @param _endingPrice - Price of item (in wei) at end of auction.
    /// @param _duration - Length of auction (in seconds).
    /// @param _seller - Seller, if not the message sender
    function createAuction(
        uint256 _tokenId,
        uint256 _startingPrice,
        uint256 _endingPrice,
        uint256 _duration,
        address _seller
    )
        external
    {
        // Sanity check that no inputs overflow how many bits we've allocated
        // to store them in the auction struct.
        require(_startingPrice == uint256(uint128(_startingPrice)));
        require(_endingPrice == uint256(uint128(_endingPrice)));
        require(_duration == uint256(uint64(_duration)));

        require(msg.sender == address(nonFungibleContract));
        _escrow(_seller, _tokenId);
        Auction memory auction = Auction(
            _seller,
            uint128(_startingPrice),
            uint128(_endingPrice),
            uint64(_duration),
            uint64(now)
        );
        _addAuction(_tokenId, auction);
    }

    /// @dev Updates lastSalePrice if seller is the nft contract
    /// Otherwise, works the same as default bid method.
    function bid(uint256 _tokenId)
        external
        payable
    {
        // _bid verifies token ID size
        address seller = tokenIdToAuction[_tokenId].seller;
        uint256 price = _bid(_tokenId, msg.value);
        _transfer(msg.sender, _tokenId);

        // If not a gen0 auction, exit
        if (seller == address(nonFungibleContract)) {
            // Track gen0 sale prices
            lastGen0SalePrices[gen0SaleCount % 5] = price;
            gen0SaleCount++;
        }
    }

    function averageGen0SalePrice() external view returns (uint256) {
        uint256 sum = 0;
        for (uint256 i = 0; i < 5; i++) {
            sum += lastGen0SalePrices[i];
        }
        return sum / 5;
    }

}


/// @title Handles creating auctions for sale and siring of kitties.
///  This wrapper of ReverseAuction exists only so that users can create
///  auctions with only one transaction.
contract KittyAuction is KittyBreeding {

    // @notice The auction contract variables are defined in KittyBase to allow
    //  us to refer to them in KittyOwnership to prevent accidental transfers.
    // `saleAuction` refers to the auction for gen0 and p2p sale of kitties.
    // `siringAuction` refers to the auction for siring rights of kitties.

    /// @dev Sets the reference to the sale auction.
    /// @param _address - Address of sale contract.
    function setSaleAuctionAddress(address _address) external onlyCEO {
        SaleClockAuction candidateContract = SaleClockAuction(_address);

        // NOTE: verify that a contract is what we expect - https://github.com/Lunyr/crowdsale-contracts/blob/cfadd15986c30521d8ba7d5b6f57b4fefcc7ac38/contracts/LunyrToken.sol#L117
        require(candidateContract.isSaleClockAuction());

        // Set the new contract address
        saleAuction = candidateContract;
    }

    /// @dev Sets the reference to the siring auction.
    /// @param _address - Address of siring contract.
    function setSiringAuctionAddress(address _address) external onlyCEO {
        SiringClockAuction candidateContract = SiringClockAuction(_address);

        // NOTE: verify that a contract is what we expect - https://github.com/Lunyr/crowdsale-contracts/blob/cfadd15986c30521d8ba7d5b6f57b4fefcc7ac38/contracts/LunyrToken.sol#L117
        require(candidateContract.isSiringClockAuction());

        // Set the new contract address
        siringAuction = candidateContract;
    }

    /// @dev Put a kitty up for auction.
    ///  Does some ownership trickery to create auctions in one tx.
    function createSaleAuction(
        uint256 _kittyId,
        uint256 _startingPrice,
        uint256 _endingPrice,
        uint256 _duration
    )
        external
        whenNotPaused
    {
        // Auction contract checks input sizes
        // If kitty is already on any auction, this will throw
        // because it will be owned by the auction contract.
        require(_owns(msg.sender, _kittyId));
        // Ensure the kitty is not pregnant to prevent the auction
        // contract accidentally receiving ownership of the child.
        // NOTE: the kitty IS allowed to be in a cooldown.
        require(!isPregnant(_kittyId));
        _approve(_kittyId, saleAuction);
        // Sale auction throws if inputs are invalid and clears
        // transfer and sire approval after escrowing the kitty.
        saleAuction.createAuction(
            _kittyId,
            _startingPrice,
            _endingPrice,
            _duration,
            msg.sender
        );
    }

    /// @dev Put a kitty up for auction to be sire.
    ///  Performs checks to ensure the kitty can be sired, then
    ///  delegates to reverse auction.
    function createSiringAuction(
        uint256 _kittyId,
        uint256 _startingPrice,
        uint256 _endingPrice,
        uint256 _duration
    )
        external
        whenNotPaused
    {
        // Auction contract checks input sizes
        // If kitty is already on any auction, this will throw
        // because it will be owned by the auction contract.
        require(_owns(msg.sender, _kittyId));
        require(isReadyToBreed(_kittyId));
        _approve(_kittyId, siringAuction);
        // Siring auction throws if inputs are invalid and clears
        // transfer and sire approval after escrowing the kitty.
        siringAuction.createAuction(
            _kittyId,
            _startingPrice,
            _endingPrice,
            _duration,
            msg.sender
        );
    }

    /// @dev Completes a siring auction by bidding.
    ///  Immediately breeds the winning matron with the sire on auction.
    /// @param _sireId - ID of the sire on auction.
    /// @param _matronId - ID of the matron owned by the bidder.
    function bidOnSiringAuction(
        uint256 _sireId,
        uint256 _matronId
    )
        external
        payable
        whenNotPaused
    {
        // Auction contract checks input sizes
        require(_owns(msg.sender, _matronId));
        require(isReadyToBreed(_matronId));
        require(_canBreedWithViaAuction(_matronId, _sireId));

        // Define the current price of the auction.
        uint256 currentPrice = siringAuction.getCurrentPrice(_sireId);
        require(msg.value >= currentPrice + autoBirthFee);

        // Siring auction will throw if the bid fails.
        siringAuction.bid.value(msg.value - autoBirthFee)(_sireId);
        _breedWith(uint32(_matronId), uint32(_sireId));
    }

    /// @dev Transfers the balance of the sale auction contract
    /// to the KittyCore contract. We use two-step withdrawal to
    /// prevent two transfer calls in the auction bid function.
    function withdrawAuctionBalances() external onlyCLevel {
        saleAuction.withdrawBalance();
        siringAuction.withdrawBalance();
    }
}


/// @title all functions related to creating kittens
contract KittyMinting is KittyAuction {

    // Limits the number of cats the contract owner can ever create.
    uint256 public constant PROMO_CREATION_LIMIT = 5000;
    uint256 public constant GEN0_CREATION_LIMIT = 45000;

    // Constants for gen0 auctions.
    uint256 public constant GEN0_STARTING_PRICE = 10 finney;
    uint256 public constant GEN0_AUCTION_DURATION = 1 days;

    // Counts the number of cats the contract owner has created.
    uint256 public promoCreatedCount;
    uint256 public gen0CreatedCount;

    /// @dev we can create promo kittens, up to a limit. Only callable by COO
    /// @param _genes the encoded genes of the kitten to be created, any value is accepted
    /// @param _owner the future owner of the created kittens. Default to contract COO
    function createPromoKitty(uint256 _genes, address _owner) external onlyCOO {
        address kittyOwner = _owner;
        if (kittyOwner == address(0)) {
             kittyOwner = cooAddress;
        }
        require(promoCreatedCount < PROMO_CREATION_LIMIT);

        promoCreatedCount++;
        _createKitty(0, 0, 0, _genes, kittyOwner);
    }

    /// @dev Creates a new gen0 kitty with the given genes and
    ///  creates an auction for it.
    function createGen0Auction(uint256 _genes) external onlyCOO {
        require(gen0CreatedCount < GEN0_CREATION_LIMIT);

        uint256 kittyId = _createKitty(0, 0, 0, _genes, address(this));
        _approve(kittyId, saleAuction);

        saleAuction.createAuction(
            kittyId,
            _computeNextGen0Price(),
            0,
            GEN0_AUCTION_DURATION,
            address(this)
        );

        gen0CreatedCount++;
    }

    /// @dev Computes the next gen0 auction starting price, given
    ///  the average of the past 5 prices + 50%.
    function _computeNextGen0Price() internal view returns (uint256) {
        uint256 avePrice = saleAuction.averageGen0SalePrice();

        // Sanity check to ensure we don't overflow arithmetic
        require(avePrice == uint256(uint128(avePrice)));

        uint256 nextPrice = avePrice + (avePrice / 2);

        // We never auction for less than starting price
        if (nextPrice < GEN0_STARTING_PRICE) {
            nextPrice = GEN0_STARTING_PRICE;
        }

        return nextPrice;
    }
}


/// @title CryptoKitties: Collectible, breedable, and oh-so-adorable cats on the Ethereum blockchain.
/// @author Axiom Zen (https://www.axiomzen.co)
/// @dev The main CryptoKitties contract, keeps track of kittens so they don't wander around and get lost.
contract KittyCore is KittyMinting {

    // This is the main CryptoKitties contract. In order to keep our code seperated into logical sections,
    // we've broken it up in two ways. First, we have several seperately-instantiated sibling contracts
    // that handle auctions and our super-top-secret genetic combination algorithm. The auctions are
    // seperate since their logic is somewhat complex and there's always a risk of subtle bugs. By keeping
    // them in their own contracts, we can upgrade them without disrupting the main contract that tracks
    // kitty ownership. The genetic combination algorithm is kept seperate so we can open-source all of
    // the rest of our code without making it _too_ easy for folks to figure out how the genetics work.
    // Don't worry, I'm sure someone will reverse engineer it soon enough!
    //
    // Secondly, we break the core contract into multiple files using inheritence, one for each major
    // facet of functionality of CK. This allows us to keep related code bundled together while still
    // avoiding a single giant file with everything in it. The breakdown is as follows:
    //
    //      - KittyBase: This is where we define the most fundamental code shared throughout the core
    //             functionality. This includes our main data storage, constants and data types, plus
    //             internal functions for managing these items.
    //
    //      - KittyAccessControl: This contract manages the various addresses and constraints for operations
    //             that can be executed only by specific roles. Namely CEO, CFO and COO.
    //
    //      - KittyOwnership: This provides the methods required for basic non-fungible token
    //             transactions, following the draft ERC-721 spec (https://github.com/ethereum/EIPs/issues/721).
    //
    //      - KittyBreeding: This file contains the methods necessary to breed cats together, including
    //             keeping track of siring offers, and relies on an external genetic combination contract.
    //
    //      - KittyAuctions: Here we have the public methods for auctioning or bidding on cats or siring
    //             services. The actual auction functionality is handled in two sibling contracts (one
    //             for sales and one for siring), while auction creation and bidding is mostly mediated
    //             through this facet of the core contract.
    //
    //      - KittyMinting: This final facet contains the functionality we use for creating new gen0 cats.
    //             We can make up to 5000 "promo" cats that can be given away (especially important when
    //             the community is new), and all others can only be created and then immediately put up
    //             for auction via an algorithmically determined starting price. Regardless of how they
    //             are created, there is a hard limit of 50k gen0 cats. After that, it's all up to the
    //             community to breed, breed, breed!

    // Set in case the core contract is broken and an upgrade is required
    address public newContractAddress;

    /// @notice Creates the main CryptoKitties smart contract instance.
    function KittyCore() public {
        // Starts paused.
        paused = true;

        // the creator of the contract is the initial CEO
        ceoAddress = msg.sender;

        // the creator of the contract is also the initial COO
        cooAddress = msg.sender;

        // start with the mythical kitten 0 - so we don't have generation-0 parent issues
        _createKitty(0, 0, 0, uint256(-1), address(0));
    }

    /// @dev Used to mark the smart contract as upgraded, in case there is a serious
    ///  breaking bug. This method does nothing but keep track of the new contract and
    ///  emit a message indicating that the new address is set. It's up to clients of this
    ///  contract to update to the new contract address in that case. (This contract will
    ///  be paused indefinitely if such an upgrade takes place.)
    /// @param _v2Address new address
    function setNewAddress(address _v2Address) external onlyCEO whenPaused {
        // See README.md for updgrade plan
        newContractAddress = _v2Address;
        ContractUpgrade(_v2Address);
    }

    /// @notice No tipping!
    /// @dev Reject all Ether from being sent here, unless it's from one of the
    ///  two auction contracts. (Hopefully, we can prevent user accidents.)
    function() external payable {
        require(
            msg.sender == address(saleAuction) ||
            msg.sender == address(siringAuction)
        );
    }

    /// @notice Returns all the relevant information about a specific kitty.
    /// @param _id The ID of the kitty of interest.
    function getKitty(uint256 _id)
        external
        view
        returns (
        bool isGestating,
        bool isReady,
        uint256 cooldownIndex,
        uint256 nextActionAt,
        uint256 siringWithId,
        uint256 birthTime,
        uint256 matronId,
        uint256 sireId,
        uint256 generation,
        uint256 genes
    ) {
        Kitty storage kit = kitties[_id];

        // if this variable is 0 then it's not gestating
        isGestating = (kit.siringWithId != 0);
        isReady = (kit.cooldownEndBlock <= block.number);
        cooldownIndex = uint256(kit.cooldownIndex);
        nextActionAt = uint256(kit.cooldownEndBlock);
        siringWithId = uint256(kit.siringWithId);
        birthTime = uint256(kit.birthTime);
        matronId = uint256(kit.matronId);
        sireId = uint256(kit.sireId);
        generation = uint256(kit.generation);
        genes = kit.genes;
    }

    /// @dev Override unpause so it requires all external contract addresses
    ///  to be set before contract can be unpaused. Also, we can't have
    ///  newContractAddress set either, because then the contract was upgraded.
    /// @notice This is public rather than external so we can call super.unpause
    ///  without using an expensive CALL.
    function unpause() public onlyCEO whenPaused {
        require(saleAuction != address(0));
        require(siringAuction != address(0));
        require(geneScience != address(0));
        require(newContractAddress == address(0));

        // Actually unpause the contract.
        super.unpause();
    }

    // @dev Allows the CFO to capture the balance available to the contract.
    function withdrawBalance() external onlyCFO {
        uint256 balance = this.balance;
        // Subtract all the currently pregnant kittens we have, plus 1 of margin.
        uint256 subtractFees = (pregnantKitties + 1) * autoBirthFee;

        if (balance > subtractFees) {
            cfoAddress.send(balance - subtractFees);
        }
    }
}

// File: contracts/ERC721/ERC721ReceiverDraft.sol

pragma solidity ^0.4.24;


/// @title ERC721ReceiverDraft
/// @dev Interface for any contract that wants to support safeTransfers from
///  ERC721 asset contracts.
/// @dev Note: this is the interface defined from 
///  https://github.com/ethereum/EIPs/commit/2bddd126def7c046e1e62408dc2b51bdd9e57f0f
///  to https://github.com/ethereum/EIPs/commit/27788131d5975daacbab607076f2ee04624f9dbb 
///  and is not the final interface.
///  Due to the extended period of time this revision was specified in the draft,
///  we are supporting both this and the newer (final) interface in order to be 
///  compatible with any ERC721 implementations that may have used this interface.
contract ERC721ReceiverDraft {

    /// @dev Magic value to be returned upon successful reception of an NFT
    ///  Equals to `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`,
    ///  which can be also obtained as `ERC721ReceiverDraft(0).onERC721Received.selector`
    /// @dev see https://github.com/ethereum/EIPs/commit/2bddd126def7c046e1e62408dc2b51bdd9e57f0f
    bytes4 internal constant ERC721_RECEIVED_DRAFT = 0xf0b9e5ba;

    /// @notice Handle the receipt of an NFT
    /// @dev The ERC721 smart contract calls this function on the recipient
    ///  after a `transfer`. This function MAY throw to revert and reject the
    ///  transfer. This function MUST use 50,000 gas or less. Return of other
    ///  than the magic value MUST result in the transaction being reverted.
    ///  Note: the contract address is always the message sender.
    /// @param _from The sending address 
    /// @param _tokenId The NFT identifier which is being transfered
    /// @param data Additional data with no specified format
    /// @return `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`
    ///  unless throwing
    function onERC721Received(address _from, uint256 _tokenId, bytes data) external returns(bytes4);
}

// File: contracts/ERC721/ERC721ReceiverFinal.sol

pragma solidity ^0.4.24;


/// @title ERC721ReceiverFinal
/// @notice Interface for any contract that wants to support safeTransfers from
///  ERC721 asset contracts.
///  @dev Note: this is the final interface as defined at http://erc721.org
contract ERC721ReceiverFinal {

    /// @dev Magic value to be returned upon successful reception of an NFT
    ///  Equals to `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`,
    ///  which can be also obtained as `ERC721ReceiverFinal(0).onERC721Received.selector`
    /// @dev see https://github.com/OpenZeppelin/openzeppelin-solidity/blob/v1.12.0/contracts/token/ERC721/ERC721Receiver.sol
    bytes4 internal constant ERC721_RECEIVED_FINAL = 0x150b7a02;

    /// @notice Handle the receipt of an NFT
    /// @dev The ERC721 smart contract calls this function on the recipient
    /// after a `safetransfer`. This function MAY throw to revert and reject the
    /// transfer. Return of other than the magic value MUST result in the
    /// transaction being reverted.
    /// Note: the contract address is always the message sender.
    /// @param _operator The address which called `safeTransferFrom` function
    /// @param _from The address which previously owned the token
    /// @param _tokenId The NFT identifier which is being transferred
    /// @param _data Additional data with no specified format
    /// @return `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
    function onERC721Received(
        address _operator,
        address _from,
        uint256 _tokenId,
        bytes _data
    )
    public
        returns (bytes4);
}

// File: contracts/ERC721/ERC721Receivable.sol

pragma solidity ^0.4.24;



/// @title ERC721Receivable handles the reception of ERC721 tokens
///  See ERC721 specification
/// @author Christopher Scott
/// @dev These functions are public, and could be called by anyone, even in the case
///  where no NFTs have been transferred. Since it's not a reliable source of
///  truth about ERC721 tokens being transferred, we save the gas and don't
///  bother emitting a (potentially spurious) event as found in 
///  https://github.com/OpenZeppelin/openzeppelin-solidity/blob/5471fc808a17342d738853d7bf3e9e5ef3108074/contracts/mocks/ERC721ReceiverMock.sol
contract ERC721Receivable is ERC721ReceiverDraft, ERC721ReceiverFinal {

    /// @notice Handle the receipt of an NFT
    /// @dev The ERC721 smart contract calls this function on the recipient
    ///  after a `transfer`. This function MAY throw to revert and reject the
    ///  transfer. This function MUST use 50,000 gas or less. Return of other
    ///  than the magic value MUST result in the transaction being reverted.
    ///  Note: the contract address is always the message sender.
    /// @param _from The sending address 
    /// @param _tokenId The NFT identifier which is being transfered
    /// @param data Additional data with no specified format
    /// @return `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`
    ///  unless throwing
    function onERC721Received(address _from, uint256 _tokenId, bytes data) external returns(bytes4) {
        _from;
        _tokenId;
        data;

        // emit ERC721Received(_operator, _from, _tokenId, _data, gasleft());

        return ERC721_RECEIVED_DRAFT;
    }

    /// @notice Handle the receipt of an NFT
    /// @dev The ERC721 smart contract calls this function on the recipient
    /// after a `safetransfer`. This function MAY throw to revert and reject the
    /// transfer. Return of other than the magic value MUST result in the
    /// transaction being reverted.
    /// Note: the contract address is always the message sender.
    /// @param _operator The address which called `safeTransferFrom` function
    /// @param _from The address which previously owned the token
    /// @param _tokenId The NFT identifier which is being transferred
    /// @param _data Additional data with no specified format
    /// @return `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
    function onERC721Received(
        address _operator,
        address _from,
        uint256 _tokenId,
        bytes _data
    )
        public
        returns(bytes4)
    {
        _operator;
        _from;
        _tokenId;
        _data;

        // emit ERC721Received(_operator, _from, _tokenId, _data, gasleft());

        return ERC721_RECEIVED_FINAL;
    }

}

// File: contracts/ERC223/ERC223Receiver.sol

pragma solidity ^0.4.24;


/// @title ERC223Receiver ensures we are ERC223 compatible
/// @author Christopher Scott
contract ERC223Receiver {
    
    bytes4 public constant ERC223_ID = 0xc0ee0b8a;

    struct TKN {
        address sender;
        uint value;
        bytes data;
        bytes4 sig;
    }
    
    /// @notice tokenFallback is called from an ERC223 compatible contract
    /// @param _from the address from which the token was sent
    /// @param _value the amount of tokens sent
    /// @param _data the data sent with the transaction
    function tokenFallback(address _from, uint _value, bytes _data) public pure {
        _from;
        _value;
        _data;
    //   TKN memory tkn;
    //   tkn.sender = _from;
    //   tkn.value = _value;
    //   tkn.data = _data;
    //   uint32 u = uint32(_data[3]) + (uint32(_data[2]) << 8) + (uint32(_data[1]) << 16) + (uint32(_data[0]) << 24);
    //   tkn.sig = bytes4(u);
      
      /* tkn variable is analogue of msg variable of Ether transaction
      *  tkn.sender is person who initiated this token transaction   (analogue of msg.sender)
      *  tkn.value the number of tokens that were sent   (analogue of msg.value)
      *  tkn.data is data of token transaction   (analogue of msg.data)
      *  tkn.sig is 4 bytes signature of function
      *  if data of token transaction is a function execution
      */

    }
}

// File: contracts/ERC1271/ERC1271.sol

pragma solidity ^0.4.24;

contract ERC1271 {

    /// @dev bytes4(keccak256("isValidSignature(bytes32,bytes)")
    bytes4 internal constant ERC1271_VALIDSIGNATURE = 0x1626ba7e;

    /// @dev Should return whether the signature provided is valid for the provided data
    /// @param hash 32-byte hash of the data that is signed
    /// @param _signature Signature byte array associated with _data
    ///  MUST return the bytes4 magic value 0x1626ba7e when function passes.
    ///  MUST NOT modify state (using STATICCALL for solc < 0.5, view modifier for solc > 0.5)
    ///  MUST allow external calls
    function isValidSignature(
        bytes32 hash, 
        bytes _signature)
        external
        view 
        returns (bytes4);
}

// File: contracts/ECDSA.sol

pragma solidity ^0.4.24;


/// @title ECDSA is a library that contains useful methods for working with ECDSA signatures
library ECDSA {

    /// @notice Extracts the r, s, and v components from the `sigData` field starting from the `offset`
    /// @dev Note: does not do any bounds checking on the arguments!
    /// @param sigData the signature data; could be 1 or more packed signatures.
    /// @param offset the offset in sigData from which to start unpacking the signature components.
    function extractSignature(bytes sigData, uint256 offset) internal pure returns  (bytes32 r, bytes32 s, uint8 v) {
        // Divide the signature in r, s and v variables
        // ecrecover takes the signature parameters, and the only way to get them
        // currently is to use assembly.
        // solium-disable-next-line security/no-inline-assembly
        assembly {
             let dataPointer := add(sigData, offset)
             r := mload(add(dataPointer, 0x20))
             s := mload(add(dataPointer, 0x40))
             v := byte(0, mload(add(dataPointer, 0x60)))
        }
    
        return (r, s, v);
    }
}

// File: contracts/Wallet/CoreWallet.sol

pragma solidity ^0.4.24;






/// @title Core Wallet
/// @notice A basic smart contract wallet with cosigner functionality. The notion of "cosigner" is
///  the simplest possible multisig solution, a two-of-two signature scheme. It devolves nicely
///  to "one-of-one" (i.e. singlesig) by simply having the cosigner set to the same value as
///  the main signer.
/// 
///  Most "advanced" functionality (deadman's switch, multiday recovery flows, blacklisting, etc)
///  can be implemented externally to this smart contract, either as an additional smart contract
///  (which can be tracked as a signer without cosigner, or as a cosigner) or as an off-chain flow
///  using a public/private key pair as cosigner. Of course, the basic cosigning functionality could
///  also be implemented in this way, but (A) the complexity and gas cost of two-of-two multisig (as
///  implemented here) is negligable even if you don't need the cosigner functionality, and
///  (B) two-of-two multisig (as implemented here) handles a lot of really common use cases, most
///  notably third-party gas payment and off-chain blacklisting and fraud detection.
contract CoreWallet is ERC721Receivable, ERC223Receiver, ERC1271  {

    using ECDSA for bytes;

    /// @notice We require that presigned transactions use the EIP-191 signing format.
    ///  See that EIP for more info: https://github.com/ethereum/EIPs/blob/master/EIPS/eip-191.md
    byte public constant EIP191_VERSION_DATA = byte(0);
    byte public constant EIP191_PREFIX = byte(0x19);

    /// @notice This is the version of the contract.
    string public constant VERSION = "1.0.0";

    /// @notice A pre-shifted "1", used to increment the authVersion, so we can "prepend"
    ///  the authVersion to an address (for lookups in the authorizations mapping)
    ///  by using the '+' operator (which is cheaper than a shift and a mask). See the
    ///  comment on the `authorizations` variable for how this is used.
    uint256 public constant AUTH_VERSION_INCREMENTOR = (1 << 160);
    
    /// @notice The pre-shifted authVersion (to get the current authVersion as an integer,
    ///  shift this value right by 160 bits). Starts as `1 << 160` (`AUTH_VERSION_INCREMENTOR`)
    ///  See the comment on the `authorizations` variable for how this is used.
    uint256 public authVersion;

    /// @notice A mapping containing all of the addresses that are currently authorized to manage
    ///  the assets owned by this wallet.
    ///
    ///  The keys in this mapping are authorized addresses with a version number prepended,
    ///  like so: (authVersion,96)(address,160). The current authVersion MUST BE included
    ///  for each look-up; this allows us to effectively clear the entire mapping of its
    ///  contents merely by incrementing the authVersion variable. (This is important for
    ///  the emergencyRecovery() method.) Inspired by https://ethereum.stackexchange.com/a/42540
    ///
    ///  The values in this mapping are 256bit words, whose lower 20 bytes constitute "cosigners"
    ///  for each address. If an address maps to itself, then that address is said to have no cosigner.
    ///
    ///  The upper 12 bytes are reserved for future meta-data purposes.  The meta-data could refer
    ///  to the key (authorized address) or the value (cosigner) of the mapping.
    ///
    ///  Addresses that map to a non-zero cosigner in the current authVersion are called
    ///  "authorized addresses".
    mapping(uint256 => uint256) public authorizations;

    /// @notice A per-key nonce value, incremented each time a transaction is processed with that key.
    ///  Used for replay prevention. The nonce value in the transaction must exactly equal the current
    ///  nonce value in the wallet for that key. (This mirrors the way Ethereum's transaction nonce works.)
    mapping(address => uint256) public nonces;

    /// @notice A special address that is authorized to call `emergencyRecovery()`. That function
    ///  resets ALL authorization for this wallet, and must therefore be treated with utmost security.
    ///  Reasonable choices for recoveryAddress include:
    ///       - the address of a private key in cold storage
    ///       - a physically secured hardware wallet
    ///       - a multisig smart contract, possibly with a time-delayed challenge period
    ///       - the zero address, if you like performing without a safety net ;-)
    address public recoveryAddress;

    /// @notice Used to track whether or not this contract instance has been initialized. This
    ///  is necessary since it is common for this wallet smart contract to be used as the "library
    ///  code" for an clone contract. See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-1167.md
    ///  for more information about clone contracts.
    bool public initialized;
    
    /// @notice Used to decorate methods that can only be called directly by the recovery address.
    modifier onlyRecoveryAddress() {
        require(msg.sender == recoveryAddress, "sender must be recovery address");
        _;
    }

    /// @notice Used to decorate the `init` function so this can only be called one time. Necessary
    ///  since this contract will often be used as a "clone". (See above.)
    modifier onlyOnce() {
        require(!initialized, "must not already be initialized");
        initialized = true;
        _;
    }
    
    /// @notice Used to decorate methods that can only be called indirectly via an `invoke()` method.
    ///  In practice, it means that those methods can only be called by a signer/cosigner
    ///  pair that is currently authorized. Theoretically, we could factor out the
    ///  signer/cosigner verification code and use it explicitly in this modifier, but that
    ///  would either result in duplicated code, or additional overhead in the invoke()
    ///  calls (due to the stack manipulation for calling into the shared verification function).
    ///  Doing it this way makes calling the administration functions more expensive (since they
    ///  go through a explict call() instead of just branching within the contract), but it
    ///  makes invoke() more efficient. We assume that invoke() will be used much, much more often
    ///  than any of the administration functions.
    modifier onlyInvoked() {
        require(msg.sender == address(this), "must be called from `invoke()`");
        _;
    }
    
    /// @notice Emitted when an authorized address is added, removed, or modified. When an
    ///  authorized address is removed ("deauthorized"), cosigner will be address(0) in
    ///  this event.
    ///  
    ///  NOTE: When emergencyRecovery() is called, all existing addresses are deauthorized
    ///  WITHOUT Authorized(addr, 0) being emitted. If you are keeping an off-chain mirror of
    ///  authorized addresses, you must also watch for EmergencyRecovery events.
    /// @dev hash is 0xf5a7f4fb8a92356e8c8c4ae7ac3589908381450500a7e2fd08c95600021ee889
    /// @param authorizedAddress the address to authorize or unauthorize
    /// @param cosigner the 2-of-2 signatory (optional).
    event Authorized(address authorizedAddress, uint256 cosigner);
    
    /// @notice Emitted when an emergency recovery has been performed. If this event is fired,
    ///  ALL previously authorized addresses have been deauthorized and the only authorized
    ///  address is the authorizedAddress indicated in this event.
    /// @dev hash is 0xe12d0bbeb1d06d7a728031056557140afac35616f594ef4be227b5b172a604b5
    /// @param authorizedAddress the new authorized address
    /// @param cosigner the cosigning address for `authorizedAddress`
    event EmergencyRecovery(address authorizedAddress, uint256 cosigner);

    /// @notice Emitted when the recovery address changes. Either (but not both) of the
    ///  parameters may be zero.
    /// @dev hash is 0x568ab3dedd6121f0385e007e641e74e1f49d0fa69cab2957b0b07c4c7de5abb6
    /// @param previousRecoveryAddress the previous recovery address
    /// @param newRecoveryAddress the new recovery address
    event RecoveryAddressChanged(address previousRecoveryAddress, address newRecoveryAddress);

    /// @dev Emitted when this contract receives a non-zero amount ether via the fallback function
    ///  (i.e. This event is not fired if the contract receives ether as part of a method invocation)
    /// @param from the address which sent you ether
    /// @param value the amount of ether sent
    event Received(address from, uint value);

    /// @notice Emitted whenever a transaction is processed sucessfully from this wallet. Includes
    ///  both simple send ether transactions, as well as other smart contract invocations.
    /// @dev hash is 0x101214446435ebbb29893f3348e3aae5ea070b63037a3df346d09d3396a34aee
    /// @param hash The hash of the entire operation set. 0 is returned when emitted from `invoke0()`.
    /// @param result A bitfield of the results of the operations. A bit of 0 means success, and 1 means failure.
    /// @param numOperations A count of the number of operations processed
    event InvocationSuccess(
        bytes32 hash,
        uint256 result,
        uint256 numOperations
    );

    /// @notice The shared initialization code used to setup the contract state regardless of whether or
    ///  not the clone pattern is being used.
    /// @param _authorizedAddress the initial authorized address, must not be zero!
    /// @param _cosigner the initial cosigning address for `_authorizedAddress`, can be equal to `_authorizedAddress`
    /// @param _recoveryAddress the initial recovery address for the wallet, can be address(0)
    function init(address _authorizedAddress, uint256 _cosigner, address _recoveryAddress) public onlyOnce {
        require(_authorizedAddress != _recoveryAddress, "Do not use the recovery address as an authorized address.");
        require(address(_cosigner) != _recoveryAddress, "Do not use the recovery address as a cosigner.");
        require(_authorizedAddress != address(0), "Authorized addresses must not be zero.");
        require(address(_cosigner) != address(0), "Initial cosigner must not be zero.");
        
        recoveryAddress = _recoveryAddress;
        // set initial authorization value
        authVersion = AUTH_VERSION_INCREMENTOR;
        // add initial authorized address
        authorizations[authVersion + uint256(_authorizedAddress)] = _cosigner;
        
        emit Authorized(_authorizedAddress, _cosigner);
    }

    /// @notice The fallback function, invoked whenever we receive a transaction that doesn't call any of our
    ///  named functions. In particular, this method is called when we are the target of a simple send transaction
    ///  or when someone tries to call a method that we don't implement. We assume that a "correct" invocation of
    ///  this method only occurs when someone is trying to transfer ether to this wallet, in which case and the
    ///  `msg.data.length` will be 0.
    ///
    ///  NOTE: Some smart contracts send 0 eth as part of a more complex
    ///  operation (-cough- CryptoKitties -cough-) ; ideally, we'd `require(msg.value > 0)` here, but to work
    ///  with those kinds of smart contracts, we accept zero sends and just skip logging in that case.
    function() external payable {
        require(msg.data.length == 0, "Invalid transaction.");
        if (msg.value > 0) {
            emit Received(msg.sender, msg.value);
        }
    }
    
    /// @notice Configures an authorizable address. Can be used in four ways:
    ///   - Add a new signer/cosigner pair (cosigner must be non-zero)
    ///   - Set or change the cosigner for an existing signer (if authorizedAddress != cosigner)
    ///   - Remove the cosigning requirement for a signer (if authorizedAddress == cosigner)
    ///   - Remove a signer (if cosigner == address(0))
    /// @dev Must be called through `invoke()`
    /// @param _authorizedAddress the address to configure authorization
    /// @param _cosigner the corresponding cosigning address
    function setAuthorized(address _authorizedAddress, uint256 _cosigner) external onlyInvoked {
        // TODO: Allowing a signer to remove itself is actually pretty terrible; it could result in the user
        //  removing their only available authorized key. Unfortunately, due to how the invocation forwarding
        //  works, we don't actually _know_ which signer was used to call this method, so there's no easy way
        //  to prevent this.
        
        // TODO: Allowing the backup key to be set as an authorized address bypasses the recovery mechanisms.
        //  Dapper can prevent this with offchain logic and the cosigner, but it would be nice to have 
        //  this enforced by the smart contract logic itself.
        
        require(_authorizedAddress != address(0), "Authorized addresses must not be zero.");
        require(_authorizedAddress != recoveryAddress, "Do not use the recovery address as an authorized address.");
        require(address(_cosigner) == address(0) || address(_cosigner) != recoveryAddress, "Do not use the recovery address as a cosigner.");
 
        authorizations[authVersion + uint256(_authorizedAddress)] = _cosigner;
        emit Authorized(_authorizedAddress, _cosigner);
    }
    
    /// @notice Performs an emergency recovery operation, removing all existing authorizations and setting
    ///  a sole new authorized address with optional cosigner. THIS IS A SCORCHED EARTH SOLUTION, and great
    ///  care should be taken to ensure that this method is never called unless it is a last resort. See the
    ///  comments above about the proper kinds of addresses to use as the recoveryAddress to ensure this method
    ///  is not trivially abused.
    /// @param _authorizedAddress the new and sole authorized address
    /// @param _cosigner the corresponding cosigner address, can be equal to _authorizedAddress
    function emergencyRecovery(address _authorizedAddress, uint256 _cosigner) external onlyRecoveryAddress {
        require(_authorizedAddress != address(0), "Authorized addresses must not be zero.");
        require(_authorizedAddress != recoveryAddress, "Do not use the recovery address as an authorized address.");
        require(address(_cosigner) != address(0), "The cosigner must not be zero.");

        // Incrementing the authVersion number effectively erases the authorizations mapping. See the comments
        // on the authorizations variable (above) for more information.
        authVersion += AUTH_VERSION_INCREMENTOR;

        // Store the new signer/cosigner pair as the only remaining authorized address
        authorizations[authVersion + uint256(_authorizedAddress)] = _cosigner;
        emit EmergencyRecovery(_authorizedAddress, _cosigner);
    }

    /// @notice Sets the recovery address, which can be zero (indicating that no recovery is possible)
    ///  Can be updated by any authorized address. This address should be set with GREAT CARE. See the
    ///  comments above about the proper kinds of addresses to use as the recoveryAddress to ensure this
    ///  mechanism is not trivially abused.
    /// @dev Must be called through `invoke()`
    /// @param _recoveryAddress the new recovery address
    function setRecoveryAddress(address _recoveryAddress) external onlyInvoked {
        require(
            address(authorizations[authVersion + uint256(_recoveryAddress)]) == address(0),
            "Do not use an authorized address as the recovery address."
        );
 
        address previous = recoveryAddress;
        recoveryAddress = _recoveryAddress;

        emit RecoveryAddressChanged(previous, recoveryAddress);
    }

    /// @notice Allows ANY caller to recover gas by way of deleting old authorization keys after
    ///  a recovery operation. Anyone can call this method to delete the old unused storage and
    ///  get themselves a bit of gas refund in the bargin.
    /// @dev keys must be known to caller or else nothing is refunded
    /// @param _version the version of the mapping which you want to delete (unshifted)
    /// @param _keys the authorization keys to delete 
    function recoverGas(uint256 _version, address[] _keys) external {
        // TODO: should this be 0xffffffffffffffffffffffff ?
        require(_version > 0 && _version < 0xffffffff, "Invalid version number.");
        
        uint256 shiftedVersion = _version << 160;

        require(shiftedVersion < authVersion, "You can only recover gas from expired authVersions.");

        for (uint256 i = 0; i < _keys.length; ++i) {
            delete(authorizations[shiftedVersion + uint256(_keys[i])]);
        }
    }

    /// @notice Should return whether the signature provided is valid for the provided data
    ///  See https://github.com/ethereum/EIPs/issues/1271
    /// @dev This function meets the following conditions as per the EIP:
    ///  MUST return the bytes4 magic value `0x1626ba7e` when function passes.
    ///  MUST NOT modify state (using `STATICCALL` for solc < 0.5, `view` modifier for solc > 0.5)
    ///  MUST allow external calls
    /// @param hash A 32 byte hash of the signed data.  The actual hash that is hashed however is the
    ///  the following tightly packed arguments: `0x19,0x0,wallet_address,hash`
    /// @param _signature Signature byte array associated with `_data`
    /// @return Magic value `0x1626ba7e` upon success, 0 otherwise.
    function isValidSignature(bytes32 hash, bytes _signature) external view returns (bytes4) {
        
        // We 'hash the hash' for the following reasons:
        // 1. `hash` is not the hash of an Ethereum transaction
        // 2. signature must target this wallet to avoid replaying the signature for another wallet
        // with the same key
        // 3. Gnosis does something similar: 
        // https://github.com/gnosis/safe-contracts/blob/102e632d051650b7c4b0a822123f449beaf95aed/contracts/GnosisSafe.sol
        bytes32 operationHash = keccak256(
            abi.encodePacked(
            EIP191_PREFIX,
            EIP191_VERSION_DATA,
            this,
            hash));

        bytes32[2] memory r;
        bytes32[2] memory s;
        uint8[2] memory v;
        address signer;
        address cosigner;

        // extract 1 or 2 signatures depending on length
        if (_signature.length == 65) {
            (r[0], s[0], v[0]) = _signature.extractSignature(0);
            signer = ecrecover(operationHash, v[0], r[0], s[0]);
            cosigner = signer;
        } else if (_signature.length == 130) {
            (r[0], s[0], v[0]) = _signature.extractSignature(0);
            (r[1], s[1], v[1]) = _signature.extractSignature(65);
            signer = ecrecover(operationHash, v[0], r[0], s[0]);
            cosigner = ecrecover(operationHash, v[1], r[1], s[1]);
        } else {
            return 0;
        }
            
        // check for valid signature
        if (signer == address(0)) {
            return 0;
        }

        // check for valid signature
        if (cosigner == address(0)) {
            return 0;
        }

        // check to see if this is an authorized key
        if (address(authorizations[authVersion + uint256(signer)]) != cosigner) {
            return 0;
        }

        return ERC1271_VALIDSIGNATURE;
    }

    /// @notice Query if a contract implements an interface
    /// @param interfaceID The interface identifier, as specified in ERC-165
    /// @dev Interface identification is specified in ERC-165. This function
    ///  uses less than 30,000 gas.
    /// @return `true` if the contract implements `interfaceID` and
    ///  `interfaceID` is not 0xffffffff, `false` otherwise
    function supportsInterface(bytes4 interfaceID) external pure returns (bool) {
        // I am not sure why the linter is complaining about the whitespace
        return
            interfaceID == this.supportsInterface.selector || // ERC165
            interfaceID == ERC721_RECEIVED_FINAL || // ERC721 Final
            interfaceID == ERC721_RECEIVED_DRAFT || // ERC721 Draft
            interfaceID == ERC223_ID || // ERC223
            interfaceID == ERC1271_VALIDSIGNATURE; // ERC1271
    }

    /// @notice A version of `invoke()` that has no explicit signatures, and uses msg.sender
    ///  as both the signer and cosigner. Will only succeed if `msg.sender` is an authorized
    ///  signer for this wallet, with no cosigner, saving transaction size and gas in that case.
    /// @param data The data containing the transactions to be invoked; see internalInvoke for details.
    function invoke0(bytes data) external {
        // The nonce doesn't need to be incremented for transactions that don't include explicit signatures;
        // the built-in nonce of the native ethereum transaction will protect against replay attacks, and we
        // can save the gas that would be spent updating the nonce variable

        // The operation should be approved if the signer address has no cosigner (i.e. signer == cosigner)
        require(address(authorizations[authVersion + uint256(msg.sender)]) == msg.sender, "Invalid authorization.");

        internalInvoke(0, data);
    }

    /// @notice A version of `invoke()` that has one explicit signature which is used to derive the authorized
    ///  address. Uses `msg.sender` as the cosigner.
    /// @param v the v value for the signature; see https://github.com/ethereum/EIPs/blob/master/EIPS/eip-155.md
    /// @param r the r value for the signature
    /// @param s the s value for the signature
    /// @param nonce the nonce value for the signature
    /// @param authorizedAddress the address of the authorization key; this is used here so that cosigner signatures are interchangeable
    ///  between this function and `invoke2()`
    /// @param data The data containing the transactions to be invoked; see internalInvoke for details.
    function invoke1CosignerSends(uint8 v, bytes32 r, bytes32 s, uint256 nonce, address authorizedAddress, bytes data) external {
        // check signature version
        require(v == 27 || v == 28, "Invalid signature version.");

        // calculate hash
        bytes32 operationHash = keccak256(
            abi.encodePacked(
            EIP191_PREFIX,
            EIP191_VERSION_DATA,
            this,
            nonce,
            authorizedAddress,
            data));
 
        // recover signer
        address signer = ecrecover(operationHash, v, r, s);

        // check for valid signature
        require(signer != address(0), "Invalid signature.");

        // check nonce
        require(nonce == nonces[signer], "must use correct nonce");

        // check signer
        require(signer == authorizedAddress, "authorized addresses must be equal");

        // Get cosigner
        address requiredCosigner = address(authorizations[authVersion + uint256(signer)]);
        
        // The operation should be approved if the signer address has no cosigner (i.e. signer == cosigner) or
        // if the actual cosigner matches the required cosigner.
        require(requiredCosigner == signer || requiredCosigner == msg.sender, "Invalid authorization.");

        // increment nonce to prevent replay attacks
        nonces[signer] = nonce + 1;

        // call internal function
        internalInvoke(operationHash, data);
    }

    /// @notice A version of `invoke()` that has one explicit signature which is used to derive the cosigning
    ///  address. Uses `msg.sender` as the authorized address.
    /// @param v the v value for the signature; see https://github.com/ethereum/EIPs/blob/master/EIPS/eip-155.md
    /// @param r the r value for the signature
    /// @param s the s value for the signature
    /// @param data The data containing the transactions to be invoked; see internalInvoke for details.
    function invoke1SignerSends(uint8 v, bytes32 r, bytes32 s, bytes data) external {
        // check signature version
        // `ecrecover` will infact return 0 if given invalid
        // so perhaps this check is redundant
        require(v == 27 || v == 28, "Invalid signature version.");
        
        uint256 nonce = nonces[msg.sender];

        // calculate hash
        bytes32 operationHash = keccak256(
            abi.encodePacked(
            EIP191_PREFIX,
            EIP191_VERSION_DATA,
            this,
            nonce,
            msg.sender,
            data));
 
        // recover cosigner
        address cosigner = ecrecover(operationHash, v, r, s);
        
        // check for valid signature
        require(cosigner != address(0), "Invalid signature.");

        // Get required cosigner
        address requiredCosigner = address(authorizations[authVersion + uint256(msg.sender)]);
        
        // The operation should be approved if the signer address has no cosigner (i.e. signer == cosigner) or
        // if the actual cosigner matches the required cosigner.
        require(requiredCosigner == cosigner || requiredCosigner == msg.sender, "Invalid authorization.");

        // increment nonce to prevent replay attacks
        nonces[msg.sender] = nonce + 1;
 
        internalInvoke(operationHash, data);
    }

    /// @notice A version of `invoke()` that has two explicit signatures, the first is used to derive the authorized
    ///  address, the second to derive the cosigner. The value of `msg.sender` is ignored.
    /// @param v the v values for the signatures
    /// @param r the r values for the signatures
    /// @param s the s values for the signatures
    /// @param nonce the nonce value for the signature
    /// @param authorizedAddress the address of the signer; forces the signature to be unique and tied to the signers nonce 
    /// @param data The data containing the transactions to be invoked; see internalInvoke for details.
    function invoke2(uint8[2] v, bytes32[2] r, bytes32[2] s, uint256 nonce, address authorizedAddress, bytes data) external {
        // check signature versions
        // `ecrecover` will infact return 0 if given invalid
        // so perhaps these checks are redundant
        require(v[0] == 27 || v[0] == 28, "invalid signature version v[0]");
        require(v[1] == 27 || v[1] == 28, "invalid signature version v[1]");
 
        bytes32 operationHash = keccak256(
            abi.encodePacked(
            EIP191_PREFIX,
            EIP191_VERSION_DATA,
            this,
            nonce,
            authorizedAddress,
            data));
 
        // recover signer and cosigner
        address signer = ecrecover(operationHash, v[0], r[0], s[0]);
        address cosigner = ecrecover(operationHash, v[1], r[1], s[1]);

        // check for valid signatures
        require(signer != address(0), "Invalid signature for signer.");
        require(cosigner != address(0), "Invalid signature for cosigner.");

        // check signer address
        require(signer == authorizedAddress, "authorized addresses must be equal");

        // check nonces
        require(nonce == nonces[signer], "must use correct nonce for signer");

        // Get Mapping
        address requiredCosigner = address(authorizations[authVersion + uint256(signer)]);
        
        // The operation should be approved if the signer address has no cosigner (i.e. signer == cosigner) or
        // if the actual cosigner matches the required cosigner.
        require(requiredCosigner == signer || requiredCosigner == cosigner, "Invalid authorization.");

        // increment nonce to prevent replay attacks
        nonces[signer]++;

        internalInvoke(operationHash, data);
    }

    /// @dev Internal invoke call, 
    /// @param operationHash The hash of the operation
    /// @param data The data to send to the `call()` operation
    ///  The data is prefixed with a global 1 byte revert flag
    ///  If revert is 1, then any revert from a `call()` operation is rethrown.
    ///  Otherwise, the error is recorded in the `result` field of the `InvocationSuccess` event.
    ///  Immediately following the revert byte (no padding), the data format is then is a series
    ///  of 1 or more tightly packed tuples:
    ///  `<target(20),amount(32),datalength(32),data>`
    ///  If `datalength == 0`, the data field must be omitted
    function internalInvoke(bytes32 operationHash, bytes data) internal {
        // keep track of the number of operations processed
        uint256 numOps;
        // keep track of the result of each operation as a bit
        uint256 result;

        // We need to store a reference to this string as a variable so we can use it as an argument to
        // the revert call from assembly.
        string memory invalidLengthMessage = "Data field too short";
        string memory callFailed = "Call failed";

        // At an absolute minimum, the data field must be at least 85 bytes
        // <revert(1), to_address(20), value(32), data_length(32)>
        require(data.length >= 85, invalidLengthMessage);

        // Forward the call onto its actual target. Note that the target address can be `self` here, which is
        // actually the required flow for modifying the configuration of the authorized keys and recovery address.
        //
        // The assembly code below loads data directly from memory, so the enclosing function must be marked `internal`
        assembly {
            // A cursor pointing to the revert flag, starts after the length field of the data object
            let memPtr := add(data, 32)

            // The revert flag is the leftmost byte from memPtr
            let revertFlag := byte(0, mload(memPtr))

            // A pointer to the end of the data object
            let endPtr := add(memPtr, mload(data))

            // Now, memPtr is a cursor pointing to the begining of the current sub-operation
            memPtr := add(memPtr, 1)

            // Loop through data, parsing out the various sub-operations
            for { } lt(memPtr, endPtr) { } {
                // Load the length of the call data of the current operation
                // 52 = to(20) + value(32)
                let len := mload(add(memPtr, 52))
                
                // Compute a pointer to the end of the current operation
                // 84 = to(20) + value(32) + size(32)
                let opEnd := add(len, add(memPtr, 84))

                // Bail if the current operation's data overruns the end of the enclosing data buffer
                // NOTE: Comment out this bit of code and uncomment the next section if you want
                // the solidity-coverage tool to work.
                // See https://github.com/sc-forks/solidity-coverage/issues/287
                if gt(opEnd, endPtr) {
                    // The computed end of this operation goes past the end of the data buffer. Not good!
                    revert(add(invalidLengthMessage, 32), mload(invalidLengthMessage))
                }
                // NOTE: Code that is compatible with solidity-coverage
                // switch gt(opEnd, endPtr)
                // case 1 {
                //     revert(add(invalidLengthMessage, 32), mload(invalidLengthMessage))
                // }

                // This line of code packs in a lot of functionality!
                //  - load the target address from memPtr, the address is only 20-bytes but mload always grabs 32-bytes,
                //    so we have to divide the result by 2^96 to effectively right-shift by 12 bytes.
                //  - load the value field, stored at memPtr+20
                //  - pass a pointer to the call data, stored at memPtr+84
                //  - use the previously loaded len field as the size of the call data
                //  - make the call (passing all remaining gas to the child call)
                //  - check the result (0 == reverted)
                if eq(0, call(gas, div(mload(memPtr), exp(2, 96)), mload(add(memPtr, 20)), add(memPtr, 84), len, 0, 0)) {
                    
                    switch revertFlag
                    case 1 {
                        revert(add(callFailed, 32), mload(callFailed))
                    }
                    default {
                        // mark this operation as failed
                        // create the appropriate bit, 'or' with previous
                        result := or(result, exp(2, numOps))
                    }
                }

                // increment our counter
                numOps := add(numOps, 1)
             
                // Update mem pointer to point to the next sub-operation
                memPtr := opEnd
            }
        }

        // emit single event upon success
        emit InvocationSuccess(operationHash, result, numOps);
    }
}

// File: contracts/Wallet/CloneableWallet.sol

pragma solidity ^0.4.24;



/// @title Cloneable Wallet
/// @notice This contract represents a complete but non working wallet.  
///  It is meant to be deployed and serve as the contract that you clone
///  in an EIP 1167 clone setup.
/// @dev See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-1167.md
/// @dev Currently, we are seeing approximatley 933 gas overhead for using
///  the clone wallet; use `FullWallet` if you think users will overtake
///  the transaction threshold over the lifetime of the wallet.
contract CloneableWallet is CoreWallet {

    /// @dev An empty constructor that deploys a NON-FUNCTIONAL version
    ///  of `CoreWallet`
    constructor () public {
        initialized = true;
    }
}