{"Address.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Collection of functions related to the address type\n */\nlibrary Address {\n    /**\n     * @dev Returns true if `account` is a contract.\n     *\n     * [IMPORTANT]\n     * ====\n     * It is unsafe to assume that an address for which this function returns\n     * false is an externally-owned account (EOA) and not a contract.\n     *\n     * Among others, `isContract` will return false for the following\n     * types of addresses:\n     *\n     *  - an externally-owned account\n     *  - a contract in construction\n     *  - an address where a contract will be created\n     *  - an address where a contract lived, but was destroyed\n     * ====\n     */\n    function isContract(address account) internal view returns (bool) {\n        // This method relies on extcodesize, which returns 0 for contracts in\n        // construction, since the code is only stored at the end of the\n        // constructor execution.\n\n        uint256 size;\n        assembly {\n            size := extcodesize(account)\n        }\n        return size \u003e 0;\n    }\n\n    /**\n     * @dev Replacement for Solidity\u0027s `transfer`: sends `amount` wei to\n     * `recipient`, forwarding all available gas and reverting on errors.\n     *\n     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost\n     * of certain opcodes, possibly making contracts go over the 2300 gas limit\n     * imposed by `transfer`, making them unable to receive funds via\n     * `transfer`. {sendValue} removes this limitation.\n     *\n     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].\n     *\n     * IMPORTANT: because control is transferred to `recipient`, care must be\n     * taken to not create reentrancy vulnerabilities. Consider using\n     * {ReentrancyGuard} or the\n     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].\n     */\n    function sendValue(address payable recipient, uint256 amount) internal {\n        require(address(this).balance \u003e= amount, \"Address: insufficient balance\");\n\n        (bool success, ) = recipient.call{value: amount}(\"\");\n        require(success, \"Address: unable to send value, recipient may have reverted\");\n    }\n\n    /**\n     * @dev Performs a Solidity function call using a low level `call`. A\n     * plain `call` is an unsafe replacement for a function call: use this\n     * function instead.\n     *\n     * If `target` reverts with a revert reason, it is bubbled up by this\n     * function (like regular Solidity function calls).\n     *\n     * Returns the raw returned data. To convert to the expected return value,\n     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].\n     *\n     * Requirements:\n     *\n     * - `target` must be a contract.\n     * - calling `target` with `data` must not revert.\n     *\n     * _Available since v3.1._\n     */\n    function functionCall(address target, bytes memory data) internal returns (bytes memory) {\n        return functionCall(target, data, \"Address: low-level call failed\");\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with\n     * `errorMessage` as a fallback revert reason when `target` reverts.\n     *\n     * _Available since v3.1._\n     */\n    function functionCall(\n        address target,\n        bytes memory data,\n        string memory errorMessage\n    ) internal returns (bytes memory) {\n        return functionCallWithValue(target, data, 0, errorMessage);\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\n     * but also transferring `value` wei to `target`.\n     *\n     * Requirements:\n     *\n     * - the calling contract must have an ETH balance of at least `value`.\n     * - the called Solidity function must be `payable`.\n     *\n     * _Available since v3.1._\n     */\n    function functionCallWithValue(\n        address target,\n        bytes memory data,\n        uint256 value\n    ) internal returns (bytes memory) {\n        return functionCallWithValue(target, data, value, \"Address: low-level call with value failed\");\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but\n     * with `errorMessage` as a fallback revert reason when `target` reverts.\n     *\n     * _Available since v3.1._\n     */\n    function functionCallWithValue(\n        address target,\n        bytes memory data,\n        uint256 value,\n        string memory errorMessage\n    ) internal returns (bytes memory) {\n        require(address(this).balance \u003e= value, \"Address: insufficient balance for call\");\n        require(isContract(target), \"Address: call to non-contract\");\n\n        (bool success, bytes memory returndata) = target.call{value: value}(data);\n        return verifyCallResult(success, returndata, errorMessage);\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\n     * but performing a static call.\n     *\n     * _Available since v3.3._\n     */\n    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {\n        return functionStaticCall(target, data, \"Address: low-level static call failed\");\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],\n     * but performing a static call.\n     *\n     * _Available since v3.3._\n     */\n    function functionStaticCall(\n        address target,\n        bytes memory data,\n        string memory errorMessage\n    ) internal view returns (bytes memory) {\n        require(isContract(target), \"Address: static call to non-contract\");\n\n        (bool success, bytes memory returndata) = target.staticcall(data);\n        return verifyCallResult(success, returndata, errorMessage);\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\n     * but performing a delegate call.\n     *\n     * _Available since v3.4._\n     */\n    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {\n        return functionDelegateCall(target, data, \"Address: low-level delegate call failed\");\n    }\n\n    /**\n     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],\n     * but performing a delegate call.\n     *\n     * _Available since v3.4._\n     */\n    function functionDelegateCall(\n        address target,\n        bytes memory data,\n        string memory errorMessage\n    ) internal returns (bytes memory) {\n        require(isContract(target), \"Address: delegate call to non-contract\");\n\n        (bool success, bytes memory returndata) = target.delegatecall(data);\n        return verifyCallResult(success, returndata, errorMessage);\n    }\n\n    /**\n     * @dev Tool to verifies that a low level call was successful, and revert if it wasn\u0027t, either by bubbling the\n     * revert reason using the provided one.\n     *\n     * _Available since v4.3._\n     */\n    function verifyCallResult(\n        bool success,\n        bytes memory returndata,\n        string memory errorMessage\n    ) internal pure returns (bytes memory) {\n        if (success) {\n            return returndata;\n        } else {\n            // Look for revert reason and bubble it up if present\n            if (returndata.length \u003e 0) {\n                // The easiest way to bubble the revert reason is using memory via assembly\n\n                assembly {\n                    let returndata_size := mload(returndata)\n                    revert(add(32, returndata), returndata_size)\n                }\n            } else {\n                revert(errorMessage);\n            }\n        }\n    }\n}\n"},"Barn.sol":{"content":"// SPDX-License-Identifier: MIT LICENSE\n\npragma solidity ^0.8.0;\n\nimport \"./IERC721Receiver.sol\";\nimport \"./Pausable.sol\";\nimport \"./Woolf.sol\";\nimport \"./WOOL.sol\";\n\ncontract Barn is Ownable, IERC721Receiver, Pausable {\n  \n  // maximum alpha score for a Wolf\n  uint8 public constant MAX_ALPHA = 8;\n\n  // struct to store a stake\u0027s token, owner, and earning values\n  struct Stake {\n    uint16 tokenId;\n    uint80 value;\n    address owner;\n  }\n\n  event TokenStaked(address owner, uint256 tokenId, uint256 value);\n  event SheepClaimed(uint256 tokenId, uint256 earned, bool unstaked);\n  event WolfClaimed(uint256 tokenId, uint256 earned, bool unstaked);\n\n  // reference to the Woolf NFT contract\n  Woolf woolf;\n  // reference to the $WOOL contract for minting $WOOL earnings\n  WOOL wool;\n\n  // maps tokenId to stake\n  mapping(uint256 =\u003e Stake) public barn; \n  // maps alpha to all Wolf stakes with that alpha\n  mapping(uint256 =\u003e Stake[]) public pack; \n  // tracks location of each Wolf in Pack\n  mapping(uint256 =\u003e uint256) public packIndices; \n  // total alpha scores staked\n  uint256 public totalAlphaStaked = 0; \n  // any rewards distributed when no wolves are staked\n  uint256 public unaccountedRewards = 0; \n  // amount of $WOOL due for each alpha point staked\n  uint256 public woolPerAlpha = 0; \n\n  // sheep earn 10000 $WOOL per day\n  uint256 public constant DAILY_WOOL_RATE = 10000 ether;\n  // sheep must have 2 days worth of $WOOL to unstake or else it\u0027s too cold\n  uint256 public constant MINIMUM_TO_EXIT = 2 days;\n  // wolves take a 20% tax on all $WOOL claimed\n  uint256 public constant WOOL_CLAIM_TAX_PERCENTAGE = 20;\n  // there will only ever be (roughly) 2.4 billion $WOOL earned through staking\n  uint256 public constant MAXIMUM_GLOBAL_WOOL = 2400000000 ether;\n\n  // amount of $WOOL earned so far\n  uint256 public totalWoolEarned;\n  // number of Sheep staked in the Barn\n  uint256 public totalSheepStaked;\n  // the last time $WOOL was claimed\n  uint256 public lastClaimTimestamp;\n\n  // emergency rescue to allow unstaking without any checks but without $WOOL\n  bool public rescueEnabled = false;\n\n  /**\n   * @param _woolf reference to the Woolf NFT contract\n   * @param _wool reference to the $WOOL token\n   */\n  constructor(address _woolf, address _wool) { \n    woolf = Woolf(_woolf);\n    wool = WOOL(_wool);\n  }\n\n  /** STAKING */\n\n  /**\n   * adds Sheep and Wolves to the Barn and Pack\n   * @param account the address of the staker\n   * @param tokenIds the IDs of the Sheep and Wolves to stake\n   */\n  function addManyToBarnAndPack(address account, uint16[] calldata tokenIds) external {\n    require(account == _msgSender() || _msgSender() == address(woolf), \"DONT GIVE YOUR TOKENS AWAY\");\n    for (uint i = 0; i \u003c tokenIds.length; i++) {\n      if (_msgSender() != address(woolf)) { // dont do this step if its a mint + stake\n        require(woolf.ownerOf(tokenIds[i]) == _msgSender(), \"AINT YO TOKEN\");\n        woolf.transferFrom(_msgSender(), address(this), tokenIds[i]);\n      } else if (tokenIds[i] == 0) {\n        continue; // there may be gaps in the array for stolen tokens\n      }\n\n      if (isSheep(tokenIds[i])) \n        _addSheepToBarn(account, tokenIds[i]);\n      else \n        _addWolfToPack(account, tokenIds[i]);\n    }\n  }\n\n  /**\n   * adds a single Sheep to the Barn\n   * @param account the address of the staker\n   * @param tokenId the ID of the Sheep to add to the Barn\n   */\n  function _addSheepToBarn(address account, uint256 tokenId) internal whenNotPaused _updateEarnings {\n    barn[tokenId] = Stake({\n      owner: account,\n      tokenId: uint16(tokenId),\n      value: uint80(block.timestamp)\n    });\n    totalSheepStaked += 1;\n    emit TokenStaked(account, tokenId, block.timestamp);\n  }\n\n  /**\n   * adds a single Wolf to the Pack\n   * @param account the address of the staker\n   * @param tokenId the ID of the Wolf to add to the Pack\n   */\n  function _addWolfToPack(address account, uint256 tokenId) internal {\n    uint256 alpha = _alphaForWolf(tokenId);\n    totalAlphaStaked += alpha; // Portion of earnings ranges from 8 to 5\n    packIndices[tokenId] = pack[alpha].length; // Store the location of the wolf in the Pack\n    pack[alpha].push(Stake({\n      owner: account,\n      tokenId: uint16(tokenId),\n      value: uint80(woolPerAlpha)\n    })); // Add the wolf to the Pack\n    emit TokenStaked(account, tokenId, woolPerAlpha);\n  }\n\n  /** CLAIMING / UNSTAKING */\n\n  /**\n   * realize $WOOL earnings and optionally unstake tokens from the Barn / Pack\n   * to unstake a Sheep it will require it has 2 days worth of $WOOL unclaimed\n   * @param tokenIds the IDs of the tokens to claim earnings from\n   * @param unstake whether or not to unstake ALL of the tokens listed in tokenIds\n   */\n  function claimManyFromBarnAndPack(uint16[] calldata tokenIds, bool unstake) external whenNotPaused _updateEarnings {\n    uint256 owed = 0;\n    for (uint i = 0; i \u003c tokenIds.length; i++) {\n      if (isSheep(tokenIds[i]))\n        owed += _claimSheepFromBarn(tokenIds[i], unstake);\n      else\n        owed += _claimWolfFromPack(tokenIds[i], unstake);\n    }\n    if (owed == 0) return;\n    wool.mint(_msgSender(), owed);\n  }\n\n  /**\n   * realize $WOOL earnings for a single Sheep and optionally unstake it\n   * if not unstaking, pay a 20% tax to the staked Wolves\n   * if unstaking, there is a 50% chance all $WOOL is stolen\n   * @param tokenId the ID of the Sheep to claim earnings from\n   * @param unstake whether or not to unstake the Sheep\n   * @return owed - the amount of $WOOL earned\n   */\n  function _claimSheepFromBarn(uint256 tokenId, bool unstake) internal returns (uint256 owed) {\n    Stake memory stake = barn[tokenId];\n    require(stake.owner == _msgSender(), \"SWIPER, NO SWIPING\");\n    require(!(unstake \u0026\u0026 block.timestamp - stake.value \u003c MINIMUM_TO_EXIT), \"GONNA BE COLD WITHOUT TWO DAY\u0027S WOOL\");\n    if (totalWoolEarned \u003c MAXIMUM_GLOBAL_WOOL) {\n      owed = (block.timestamp - stake.value) * DAILY_WOOL_RATE / 1 days;\n    } else if (stake.value \u003e lastClaimTimestamp) {\n      owed = 0; // $WOOL production stopped already\n    } else {\n      owed = (lastClaimTimestamp - stake.value) * DAILY_WOOL_RATE / 1 days; // stop earning additional $WOOL if it\u0027s all been earned\n    }\n    if (unstake) {\n      if (random(tokenId) \u0026 1 == 1) { // 50% chance of all $WOOL stolen\n        _payWolfTax(owed);\n        owed = 0;\n      }\n      woolf.safeTransferFrom(address(this), _msgSender(), tokenId, \"\"); // send back Sheep\n      delete barn[tokenId];\n      totalSheepStaked -= 1;\n    } else {\n      _payWolfTax(owed * WOOL_CLAIM_TAX_PERCENTAGE / 100); // percentage tax to staked wolves\n      owed = owed * (100 - WOOL_CLAIM_TAX_PERCENTAGE) / 100; // remainder goes to Sheep owner\n      barn[tokenId] = Stake({\n        owner: _msgSender(),\n        tokenId: uint16(tokenId),\n        value: uint80(block.timestamp)\n      }); // reset stake\n    }\n    emit SheepClaimed(tokenId, owed, unstake);\n  }\n\n  /**\n   * realize $WOOL earnings for a single Wolf and optionally unstake it\n   * Wolves earn $WOOL proportional to their Alpha rank\n   * @param tokenId the ID of the Wolf to claim earnings from\n   * @param unstake whether or not to unstake the Wolf\n   * @return owed - the amount of $WOOL earned\n   */\n  function _claimWolfFromPack(uint256 tokenId, bool unstake) internal returns (uint256 owed) {\n    require(woolf.ownerOf(tokenId) == address(this), \"AINT A PART OF THE PACK\");\n    uint256 alpha = _alphaForWolf(tokenId);\n    Stake memory stake = pack[alpha][packIndices[tokenId]];\n    require(stake.owner == _msgSender(), \"SWIPER, NO SWIPING\");\n    owed = (alpha) * (woolPerAlpha - stake.value); // Calculate portion of tokens based on Alpha\n    if (unstake) {\n      totalAlphaStaked -= alpha; // Remove Alpha from total staked\n      woolf.safeTransferFrom(address(this), _msgSender(), tokenId, \"\"); // Send back Wolf\n      Stake memory lastStake = pack[alpha][pack[alpha].length - 1];\n      pack[alpha][packIndices[tokenId]] = lastStake; // Shuffle last Wolf to current position\n      packIndices[lastStake.tokenId] = packIndices[tokenId];\n      pack[alpha].pop(); // Remove duplicate\n      delete packIndices[tokenId]; // Delete old mapping\n    } else {\n      pack[alpha][packIndices[tokenId]] = Stake({\n        owner: _msgSender(),\n        tokenId: uint16(tokenId),\n        value: uint80(woolPerAlpha)\n      }); // reset stake\n    }\n    emit WolfClaimed(tokenId, owed, unstake);\n  }\n\n  /**\n   * emergency unstake tokens\n   * @param tokenIds the IDs of the tokens to claim earnings from\n   */\n  function rescue(uint256[] calldata tokenIds) external {\n    require(rescueEnabled, \"RESCUE DISABLED\");\n    uint256 tokenId;\n    Stake memory stake;\n    Stake memory lastStake;\n    uint256 alpha;\n    for (uint i = 0; i \u003c tokenIds.length; i++) {\n      tokenId = tokenIds[i];\n      if (isSheep(tokenId)) {\n        stake = barn[tokenId];\n        require(stake.owner == _msgSender(), \"SWIPER, NO SWIPING\");\n        woolf.safeTransferFrom(address(this), _msgSender(), tokenId, \"\"); // send back Sheep\n        delete barn[tokenId];\n        totalSheepStaked -= 1;\n        emit SheepClaimed(tokenId, 0, true);\n      } else {\n        alpha = _alphaForWolf(tokenId);\n        stake = pack[alpha][packIndices[tokenId]];\n        require(stake.owner == _msgSender(), \"SWIPER, NO SWIPING\");\n        totalAlphaStaked -= alpha; // Remove Alpha from total staked\n        woolf.safeTransferFrom(address(this), _msgSender(), tokenId, \"\"); // Send back Wolf\n        lastStake = pack[alpha][pack[alpha].length - 1];\n        pack[alpha][packIndices[tokenId]] = lastStake; // Shuffle last Wolf to current position\n        packIndices[lastStake.tokenId] = packIndices[tokenId];\n        pack[alpha].pop(); // Remove duplicate\n        delete packIndices[tokenId]; // Delete old mapping\n        emit WolfClaimed(tokenId, 0, true);\n      }\n    }\n  }\n\n  /** ACCOUNTING */\n\n  /** \n   * add $WOOL to claimable pot for the Pack\n   * @param amount $WOOL to add to the pot\n   */\n  function _payWolfTax(uint256 amount) internal {\n    if (totalAlphaStaked == 0) { // if there\u0027s no staked wolves\n      unaccountedRewards += amount; // keep track of $WOOL due to wolves\n      return;\n    }\n    // makes sure to include any unaccounted $WOOL \n    woolPerAlpha += (amount + unaccountedRewards) / totalAlphaStaked;\n    unaccountedRewards = 0;\n  }\n\n  /**\n   * tracks $WOOL earnings to ensure it stops once 2.4 billion is eclipsed\n   */\n  modifier _updateEarnings() {\n    if (totalWoolEarned \u003c MAXIMUM_GLOBAL_WOOL) {\n      totalWoolEarned += \n        (block.timestamp - lastClaimTimestamp)\n        * totalSheepStaked\n        * DAILY_WOOL_RATE / 1 days; \n      lastClaimTimestamp = block.timestamp;\n    }\n    _;\n  }\n\n  /** ADMIN */\n\n  /**\n   * allows owner to enable \"rescue mode\"\n   * simplifies accounting, prioritizes tokens out in emergency\n   */\n  function setRescueEnabled(bool _enabled) external onlyOwner {\n    rescueEnabled = _enabled;\n  }\n\n  /**\n   * enables owner to pause / unpause minting\n   */\n  function setPaused(bool _paused) external onlyOwner {\n    if (_paused) _pause();\n    else _unpause();\n  }\n\n  /** READ ONLY */\n\n  /**\n   * checks if a token is a Sheep\n   * @param tokenId the ID of the token to check\n   * @return sheep - whether or not a token is a Sheep\n   */\n  function isSheep(uint256 tokenId) public view returns (bool sheep) {\n    (sheep, , , , , , , , , ) = woolf.tokenTraits(tokenId);\n  }\n\n  /**\n   * gets the alpha score for a Wolf\n   * @param tokenId the ID of the Wolf to get the alpha score for\n   * @return the alpha score of the Wolf (5-8)\n   */\n  function _alphaForWolf(uint256 tokenId) internal view returns (uint8) {\n    ( , , , , , , , , , uint8 alphaIndex) = woolf.tokenTraits(tokenId);\n    return MAX_ALPHA - alphaIndex; // alpha index is 0-3\n  }\n\n  /**\n   * chooses a random Wolf thief when a newly minted token is stolen\n   * @param seed a random value to choose a Wolf from\n   * @return the owner of the randomly selected Wolf thief\n   */\n  function randomWolfOwner(uint256 seed) external view returns (address) {\n    if (totalAlphaStaked == 0) return address(0x0);\n    uint256 bucket = (seed \u0026 0xFFFFFFFF) % totalAlphaStaked; // choose a value from 0 to total alpha staked\n    uint256 cumulative;\n    seed \u003e\u003e= 32;\n    // loop through each bucket of Wolves with the same alpha score\n    for (uint i = MAX_ALPHA - 3; i \u003c= MAX_ALPHA; i++) {\n      cumulative += pack[i].length * i;\n      // if the value is not inside of that bucket, keep going\n      if (bucket \u003e= cumulative) continue;\n      // get the address of a random Wolf with that alpha score\n      return pack[i][seed % pack[i].length].owner;\n    }\n    return address(0x0);\n  }\n\n  /**\n   * generates a pseudorandom number\n   * @param seed a value ensure different outcomes for different sources in the same block\n   * @return a pseudorandom value\n   */\n  function random(uint256 seed) internal view returns (uint256) {\n    return uint256(keccak256(abi.encodePacked(\n      tx.origin,\n      blockhash(block.number - 1),\n      block.timestamp,\n      seed\n    )));\n  }\n\n  function onERC721Received(\n        address,\n        address from,\n        uint256,\n        bytes calldata\n    ) external pure override returns (bytes4) {\n      require(from == address(0x0), \"Cannot send tokens to Barn directly\");\n      return IERC721Receiver.onERC721Received.selector;\n    }\n\n  \n}"},"Context.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Provides information about the current execution context, including the\n * sender of the transaction and its data. While these are generally available\n * via msg.sender and msg.data, they should not be accessed in such a direct\n * manner, since when dealing with meta-transactions the account sending and\n * paying for execution may not be the actual sender (as far as an application\n * is concerned).\n *\n * This contract is only required for intermediate, library-like contracts.\n */\nabstract contract Context {\n    function _msgSender() internal view virtual returns (address) {\n        return msg.sender;\n    }\n\n    function _msgData() internal view virtual returns (bytes calldata) {\n        return msg.data;\n    }\n}\n"},"ERC165.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\nimport \"./IERC165.sol\";\n\n/**\n * @dev Implementation of the {IERC165} interface.\n *\n * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check\n * for the additional interface id that will be supported. For example:\n *\n * ```solidity\n * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {\n *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);\n * }\n * ```\n *\n * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.\n */\nabstract contract ERC165 is IERC165 {\n    /**\n     * @dev See {IERC165-supportsInterface}.\n     */\n    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {\n        return interfaceId == type(IERC165).interfaceId;\n    }\n}\n"},"ERC20.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\nimport \"./IERC20.sol\";\nimport \"./IERC20Metadata.sol\";\nimport \"./Context.sol\";\n\n/**\n * @dev Implementation of the {IERC20} interface.\n *\n * This implementation is agnostic to the way tokens are created. This means\n * that a supply mechanism has to be added in a derived contract using {_mint}.\n * For a generic mechanism see {ERC20PresetMinterPauser}.\n *\n * TIP: For a detailed writeup see our guide\n * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How\n * to implement supply mechanisms].\n *\n * We have followed general OpenZeppelin Contracts guidelines: functions revert\n * instead returning `false` on failure. This behavior is nonetheless\n * conventional and does not conflict with the expectations of ERC20\n * applications.\n *\n * Additionally, an {Approval} event is emitted on calls to {transferFrom}.\n * This allows applications to reconstruct the allowance for all accounts just\n * by listening to said events. Other implementations of the EIP may not emit\n * these events, as it isn\u0027t required by the specification.\n *\n * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}\n * functions have been added to mitigate the well-known issues around setting\n * allowances. See {IERC20-approve}.\n */\ncontract ERC20 is Context, IERC20, IERC20Metadata {\n    mapping(address =\u003e uint256) private _balances;\n\n    mapping(address =\u003e mapping(address =\u003e uint256)) private _allowances;\n\n    uint256 private _totalSupply;\n\n    string private _name;\n    string private _symbol;\n\n    /**\n     * @dev Sets the values for {name} and {symbol}.\n     *\n     * The default value of {decimals} is 18. To select a different value for\n     * {decimals} you should overload it.\n     *\n     * All two of these values are immutable: they can only be set once during\n     * construction.\n     */\n    constructor(string memory name_, string memory symbol_) {\n        _name = name_;\n        _symbol = symbol_;\n    }\n\n    /**\n     * @dev Returns the name of the token.\n     */\n    function name() public view virtual override returns (string memory) {\n        return _name;\n    }\n\n    /**\n     * @dev Returns the symbol of the token, usually a shorter version of the\n     * name.\n     */\n    function symbol() public view virtual override returns (string memory) {\n        return _symbol;\n    }\n\n    /**\n     * @dev Returns the number of decimals used to get its user representation.\n     * For example, if `decimals` equals `2`, a balance of `505` tokens should\n     * be displayed to a user as `5.05` (`505 / 10 ** 2`).\n     *\n     * Tokens usually opt for a value of 18, imitating the relationship between\n     * Ether and Wei. This is the value {ERC20} uses, unless this function is\n     * overridden;\n     *\n     * NOTE: This information is only used for _display_ purposes: it in\n     * no way affects any of the arithmetic of the contract, including\n     * {IERC20-balanceOf} and {IERC20-transfer}.\n     */\n    function decimals() public view virtual override returns (uint8) {\n        return 18;\n    }\n\n    /**\n     * @dev See {IERC20-totalSupply}.\n     */\n    function totalSupply() public view virtual override returns (uint256) {\n        return _totalSupply;\n    }\n\n    /**\n     * @dev See {IERC20-balanceOf}.\n     */\n    function balanceOf(address account) public view virtual override returns (uint256) {\n        return _balances[account];\n    }\n\n    /**\n     * @dev See {IERC20-transfer}.\n     *\n     * Requirements:\n     *\n     * - `recipient` cannot be the zero address.\n     * - the caller must have a balance of at least `amount`.\n     */\n    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {\n        _transfer(_msgSender(), recipient, amount);\n        return true;\n    }\n\n    /**\n     * @dev See {IERC20-allowance}.\n     */\n    function allowance(address owner, address spender) public view virtual override returns (uint256) {\n        return _allowances[owner][spender];\n    }\n\n    /**\n     * @dev See {IERC20-approve}.\n     *\n     * Requirements:\n     *\n     * - `spender` cannot be the zero address.\n     */\n    function approve(address spender, uint256 amount) public virtual override returns (bool) {\n        _approve(_msgSender(), spender, amount);\n        return true;\n    }\n\n    /**\n     * @dev See {IERC20-transferFrom}.\n     *\n     * Emits an {Approval} event indicating the updated allowance. This is not\n     * required by the EIP. See the note at the beginning of {ERC20}.\n     *\n     * Requirements:\n     *\n     * - `sender` and `recipient` cannot be the zero address.\n     * - `sender` must have a balance of at least `amount`.\n     * - the caller must have allowance for ``sender``\u0027s tokens of at least\n     * `amount`.\n     */\n    function transferFrom(\n        address sender,\n        address recipient,\n        uint256 amount\n    ) public virtual override returns (bool) {\n        _transfer(sender, recipient, amount);\n\n        uint256 currentAllowance = _allowances[sender][_msgSender()];\n        require(currentAllowance \u003e= amount, \"ERC20: transfer amount exceeds allowance\");\n        unchecked {\n            _approve(sender, _msgSender(), currentAllowance - amount);\n        }\n\n        return true;\n    }\n\n    /**\n     * @dev Atomically increases the allowance granted to `spender` by the caller.\n     *\n     * This is an alternative to {approve} that can be used as a mitigation for\n     * problems described in {IERC20-approve}.\n     *\n     * Emits an {Approval} event indicating the updated allowance.\n     *\n     * Requirements:\n     *\n     * - `spender` cannot be the zero address.\n     */\n    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {\n        _approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);\n        return true;\n    }\n\n    /**\n     * @dev Atomically decreases the allowance granted to `spender` by the caller.\n     *\n     * This is an alternative to {approve} that can be used as a mitigation for\n     * problems described in {IERC20-approve}.\n     *\n     * Emits an {Approval} event indicating the updated allowance.\n     *\n     * Requirements:\n     *\n     * - `spender` cannot be the zero address.\n     * - `spender` must have allowance for the caller of at least\n     * `subtractedValue`.\n     */\n    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {\n        uint256 currentAllowance = _allowances[_msgSender()][spender];\n        require(currentAllowance \u003e= subtractedValue, \"ERC20: decreased allowance below zero\");\n        unchecked {\n            _approve(_msgSender(), spender, currentAllowance - subtractedValue);\n        }\n\n        return true;\n    }\n\n    /**\n     * @dev Moves `amount` of tokens from `sender` to `recipient`.\n     *\n     * This internal function is equivalent to {transfer}, and can be used to\n     * e.g. implement automatic token fees, slashing mechanisms, etc.\n     *\n     * Emits a {Transfer} event.\n     *\n     * Requirements:\n     *\n     * - `sender` cannot be the zero address.\n     * - `recipient` cannot be the zero address.\n     * - `sender` must have a balance of at least `amount`.\n     */\n    function _transfer(\n        address sender,\n        address recipient,\n        uint256 amount\n    ) internal virtual {\n        require(sender != address(0), \"ERC20: transfer from the zero address\");\n        require(recipient != address(0), \"ERC20: transfer to the zero address\");\n\n        _beforeTokenTransfer(sender, recipient, amount);\n\n        uint256 senderBalance = _balances[sender];\n        require(senderBalance \u003e= amount, \"ERC20: transfer amount exceeds balance\");\n        unchecked {\n            _balances[sender] = senderBalance - amount;\n        }\n        _balances[recipient] += amount;\n\n        emit Transfer(sender, recipient, amount);\n\n        _afterTokenTransfer(sender, recipient, amount);\n    }\n\n    /** @dev Creates `amount` tokens and assigns them to `account`, increasing\n     * the total supply.\n     *\n     * Emits a {Transfer} event with `from` set to the zero address.\n     *\n     * Requirements:\n     *\n     * - `account` cannot be the zero address.\n     */\n    function _mint(address account, uint256 amount) internal virtual {\n        require(account != address(0), \"ERC20: mint to the zero address\");\n\n        _beforeTokenTransfer(address(0), account, amount);\n\n        _totalSupply += amount;\n        _balances[account] += amount;\n        emit Transfer(address(0), account, amount);\n\n        _afterTokenTransfer(address(0), account, amount);\n    }\n\n    /**\n     * @dev Destroys `amount` tokens from `account`, reducing the\n     * total supply.\n     *\n     * Emits a {Transfer} event with `to` set to the zero address.\n     *\n     * Requirements:\n     *\n     * - `account` cannot be the zero address.\n     * - `account` must have at least `amount` tokens.\n     */\n    function _burn(address account, uint256 amount) internal virtual {\n        require(account != address(0), \"ERC20: burn from the zero address\");\n\n        _beforeTokenTransfer(account, address(0), amount);\n\n        uint256 accountBalance = _balances[account];\n        require(accountBalance \u003e= amount, \"ERC20: burn amount exceeds balance\");\n        unchecked {\n            _balances[account] = accountBalance - amount;\n        }\n        _totalSupply -= amount;\n\n        emit Transfer(account, address(0), amount);\n\n        _afterTokenTransfer(account, address(0), amount);\n    }\n\n    /**\n     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.\n     *\n     * This internal function is equivalent to `approve`, and can be used to\n     * e.g. set automatic allowances for certain subsystems, etc.\n     *\n     * Emits an {Approval} event.\n     *\n     * Requirements:\n     *\n     * - `owner` cannot be the zero address.\n     * - `spender` cannot be the zero address.\n     */\n    function _approve(\n        address owner,\n        address spender,\n        uint256 amount\n    ) internal virtual {\n        require(owner != address(0), \"ERC20: approve from the zero address\");\n        require(spender != address(0), \"ERC20: approve to the zero address\");\n\n        _allowances[owner][spender] = amount;\n        emit Approval(owner, spender, amount);\n    }\n\n    /**\n     * @dev Hook that is called before any transfer of tokens. This includes\n     * minting and burning.\n     *\n     * Calling conditions:\n     *\n     * - when `from` and `to` are both non-zero, `amount` of ``from``\u0027s tokens\n     * will be transferred to `to`.\n     * - when `from` is zero, `amount` tokens will be minted for `to`.\n     * - when `to` is zero, `amount` of ``from``\u0027s tokens will be burned.\n     * - `from` and `to` are never both zero.\n     *\n     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n     */\n    function _beforeTokenTransfer(\n        address from,\n        address to,\n        uint256 amount\n    ) internal virtual {}\n\n    /**\n     * @dev Hook that is called after any transfer of tokens. This includes\n     * minting and burning.\n     *\n     * Calling conditions:\n     *\n     * - when `from` and `to` are both non-zero, `amount` of ``from``\u0027s tokens\n     * has been transferred to `to`.\n     * - when `from` is zero, `amount` tokens have been minted for `to`.\n     * - when `to` is zero, `amount` of ``from``\u0027s tokens have been burned.\n     * - `from` and `to` are never both zero.\n     *\n     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n     */\n    function _afterTokenTransfer(\n        address from,\n        address to,\n        uint256 amount\n    ) internal virtual {}\n}\n"},"ERC721.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\nimport \"./IERC721.sol\";\nimport \"./IERC721Receiver.sol\";\nimport \"./IERC721Metadata.sol\";\nimport \"./Address.sol\";\nimport \"./Context.sol\";\nimport \"./Strings.sol\";\nimport \"./ERC165.sol\";\n\n/**\n * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including\n * the Metadata extension, but not including the Enumerable extension, which is available separately as\n * {ERC721Enumerable}.\n */\ncontract ERC721 is Context, ERC165, IERC721, IERC721Metadata {\n    using Address for address;\n    using Strings for uint256;\n\n    // Token name\n    string private _name;\n\n    // Token symbol\n    string private _symbol;\n\n    // Mapping from token ID to owner address\n    mapping(uint256 =\u003e address) private _owners;\n\n    // Mapping owner address to token count\n    mapping(address =\u003e uint256) private _balances;\n\n    // Mapping from token ID to approved address\n    mapping(uint256 =\u003e address) private _tokenApprovals;\n\n    // Mapping from owner to operator approvals\n    mapping(address =\u003e mapping(address =\u003e bool)) private _operatorApprovals;\n\n    /**\n     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.\n     */\n    constructor(string memory name_, string memory symbol_) {\n        _name = name_;\n        _symbol = symbol_;\n    }\n\n    /**\n     * @dev See {IERC165-supportsInterface}.\n     */\n    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {\n        return\n            interfaceId == type(IERC721).interfaceId ||\n            interfaceId == type(IERC721Metadata).interfaceId ||\n            super.supportsInterface(interfaceId);\n    }\n\n    /**\n     * @dev See {IERC721-balanceOf}.\n     */\n    function balanceOf(address owner) public view virtual override returns (uint256) {\n        require(owner != address(0), \"ERC721: balance query for the zero address\");\n        return _balances[owner];\n    }\n\n    /**\n     * @dev See {IERC721-ownerOf}.\n     */\n    function ownerOf(uint256 tokenId) public view virtual override returns (address) {\n        address owner = _owners[tokenId];\n        require(owner != address(0), \"ERC721: owner query for nonexistent token\");\n        return owner;\n    }\n\n    /**\n     * @dev See {IERC721Metadata-name}.\n     */\n    function name() public view virtual override returns (string memory) {\n        return _name;\n    }\n\n    /**\n     * @dev See {IERC721Metadata-symbol}.\n     */\n    function symbol() public view virtual override returns (string memory) {\n        return _symbol;\n    }\n\n    /**\n     * @dev See {IERC721Metadata-tokenURI}.\n     */\n    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {\n        require(_exists(tokenId), \"ERC721Metadata: URI query for nonexistent token\");\n\n        string memory baseURI = _baseURI();\n        return bytes(baseURI).length \u003e 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : \"\";\n    }\n\n    /**\n     * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each\n     * token will be the concatenation of the `baseURI` and the `tokenId`. Empty\n     * by default, can be overriden in child contracts.\n     */\n    function _baseURI() internal view virtual returns (string memory) {\n        return \"\";\n    }\n\n    /**\n     * @dev See {IERC721-approve}.\n     */\n    function approve(address to, uint256 tokenId) public virtual override {\n        address owner = ERC721.ownerOf(tokenId);\n        require(to != owner, \"ERC721: approval to current owner\");\n\n        require(\n            _msgSender() == owner || isApprovedForAll(owner, _msgSender()),\n            \"ERC721: approve caller is not owner nor approved for all\"\n        );\n\n        _approve(to, tokenId);\n    }\n\n    /**\n     * @dev See {IERC721-getApproved}.\n     */\n    function getApproved(uint256 tokenId) public view virtual override returns (address) {\n        require(_exists(tokenId), \"ERC721: approved query for nonexistent token\");\n\n        return _tokenApprovals[tokenId];\n    }\n\n    /**\n     * @dev See {IERC721-setApprovalForAll}.\n     */\n    function setApprovalForAll(address operator, bool approved) public virtual override {\n        require(operator != _msgSender(), \"ERC721: approve to caller\");\n\n        _operatorApprovals[_msgSender()][operator] = approved;\n        emit ApprovalForAll(_msgSender(), operator, approved);\n    }\n\n    /**\n     * @dev See {IERC721-isApprovedForAll}.\n     */\n    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {\n        return _operatorApprovals[owner][operator];\n    }\n\n    /**\n     * @dev See {IERC721-transferFrom}.\n     */\n    function transferFrom(\n        address from,\n        address to,\n        uint256 tokenId\n    ) public virtual override {\n        //solhint-disable-next-line max-line-length\n        require(_isApprovedOrOwner(_msgSender(), tokenId), \"ERC721: transfer caller is not owner nor approved\");\n\n        _transfer(from, to, tokenId);\n    }\n\n    /**\n     * @dev See {IERC721-safeTransferFrom}.\n     */\n    function safeTransferFrom(\n        address from,\n        address to,\n        uint256 tokenId\n    ) public virtual override {\n        safeTransferFrom(from, to, tokenId, \"\");\n    }\n\n    /**\n     * @dev See {IERC721-safeTransferFrom}.\n     */\n    function safeTransferFrom(\n        address from,\n        address to,\n        uint256 tokenId,\n        bytes memory _data\n    ) public virtual override {\n        require(_isApprovedOrOwner(_msgSender(), tokenId), \"ERC721: transfer caller is not owner nor approved\");\n        _safeTransfer(from, to, tokenId, _data);\n    }\n\n    /**\n     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients\n     * are aware of the ERC721 protocol to prevent tokens from being forever locked.\n     *\n     * `_data` is additional data, it has no specified format and it is sent in call to `to`.\n     *\n     * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.\n     * implement alternative mechanisms to perform token transfer, such as signature-based.\n     *\n     * Requirements:\n     *\n     * - `from` cannot be the zero address.\n     * - `to` cannot be the zero address.\n     * - `tokenId` token must exist and be owned by `from`.\n     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n     *\n     * Emits a {Transfer} event.\n     */\n    function _safeTransfer(\n        address from,\n        address to,\n        uint256 tokenId,\n        bytes memory _data\n    ) internal virtual {\n        _transfer(from, to, tokenId);\n        require(_checkOnERC721Received(from, to, tokenId, _data), \"ERC721: transfer to non ERC721Receiver implementer\");\n    }\n\n    /**\n     * @dev Returns whether `tokenId` exists.\n     *\n     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.\n     *\n     * Tokens start existing when they are minted (`_mint`),\n     * and stop existing when they are burned (`_burn`).\n     */\n    function _exists(uint256 tokenId) internal view virtual returns (bool) {\n        return _owners[tokenId] != address(0);\n    }\n\n    /**\n     * @dev Returns whether `spender` is allowed to manage `tokenId`.\n     *\n     * Requirements:\n     *\n     * - `tokenId` must exist.\n     */\n    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {\n        require(_exists(tokenId), \"ERC721: operator query for nonexistent token\");\n        address owner = ERC721.ownerOf(tokenId);\n        return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));\n    }\n\n    /**\n     * @dev Safely mints `tokenId` and transfers it to `to`.\n     *\n     * Requirements:\n     *\n     * - `tokenId` must not exist.\n     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n     *\n     * Emits a {Transfer} event.\n     */\n    function _safeMint(address to, uint256 tokenId) internal virtual {\n        _safeMint(to, tokenId, \"\");\n    }\n\n    /**\n     * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is\n     * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.\n     */\n    function _safeMint(\n        address to,\n        uint256 tokenId,\n        bytes memory _data\n    ) internal virtual {\n        _mint(to, tokenId);\n        require(\n            _checkOnERC721Received(address(0), to, tokenId, _data),\n            \"ERC721: transfer to non ERC721Receiver implementer\"\n        );\n    }\n\n    /**\n     * @dev Mints `tokenId` and transfers it to `to`.\n     *\n     * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible\n     *\n     * Requirements:\n     *\n     * - `tokenId` must not exist.\n     * - `to` cannot be the zero address.\n     *\n     * Emits a {Transfer} event.\n     */\n    function _mint(address to, uint256 tokenId) internal virtual {\n        require(to != address(0), \"ERC721: mint to the zero address\");\n        require(!_exists(tokenId), \"ERC721: token already minted\");\n\n        _beforeTokenTransfer(address(0), to, tokenId);\n\n        _balances[to] += 1;\n        _owners[tokenId] = to;\n\n        emit Transfer(address(0), to, tokenId);\n    }\n\n    /**\n     * @dev Destroys `tokenId`.\n     * The approval is cleared when the token is burned.\n     *\n     * Requirements:\n     *\n     * - `tokenId` must exist.\n     *\n     * Emits a {Transfer} event.\n     */\n    function _burn(uint256 tokenId) internal virtual {\n        address owner = ERC721.ownerOf(tokenId);\n\n        _beforeTokenTransfer(owner, address(0), tokenId);\n\n        // Clear approvals\n        _approve(address(0), tokenId);\n\n        _balances[owner] -= 1;\n        delete _owners[tokenId];\n\n        emit Transfer(owner, address(0), tokenId);\n    }\n\n    /**\n     * @dev Transfers `tokenId` from `from` to `to`.\n     *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.\n     *\n     * Requirements:\n     *\n     * - `to` cannot be the zero address.\n     * - `tokenId` token must be owned by `from`.\n     *\n     * Emits a {Transfer} event.\n     */\n    function _transfer(\n        address from,\n        address to,\n        uint256 tokenId\n    ) internal virtual {\n        require(ERC721.ownerOf(tokenId) == from, \"ERC721: transfer of token that is not own\");\n        require(to != address(0), \"ERC721: transfer to the zero address\");\n\n        _beforeTokenTransfer(from, to, tokenId);\n\n        // Clear approvals from the previous owner\n        _approve(address(0), tokenId);\n\n        _balances[from] -= 1;\n        _balances[to] += 1;\n        _owners[tokenId] = to;\n\n        emit Transfer(from, to, tokenId);\n    }\n\n    /**\n     * @dev Approve `to` to operate on `tokenId`\n     *\n     * Emits a {Approval} event.\n     */\n    function _approve(address to, uint256 tokenId) internal virtual {\n        _tokenApprovals[tokenId] = to;\n        emit Approval(ERC721.ownerOf(tokenId), to, tokenId);\n    }\n\n    /**\n     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.\n     * The call is not executed if the target address is not a contract.\n     *\n     * @param from address representing the previous owner of the given token ID\n     * @param to target address that will receive the tokens\n     * @param tokenId uint256 ID of the token to be transferred\n     * @param _data bytes optional data to send along with the call\n     * @return bool whether the call correctly returned the expected magic value\n     */\n    function _checkOnERC721Received(\n        address from,\n        address to,\n        uint256 tokenId,\n        bytes memory _data\n    ) private returns (bool) {\n        if (to.isContract()) {\n            try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {\n                return retval == IERC721Receiver.onERC721Received.selector;\n            } catch (bytes memory reason) {\n                if (reason.length == 0) {\n                    revert(\"ERC721: transfer to non ERC721Receiver implementer\");\n                } else {\n                    assembly {\n                        revert(add(32, reason), mload(reason))\n                    }\n                }\n            }\n        } else {\n            return true;\n        }\n    }\n\n    /**\n     * @dev Hook that is called before any token transfer. This includes minting\n     * and burning.\n     *\n     * Calling conditions:\n     *\n     * - When `from` and `to` are both non-zero, ``from``\u0027s `tokenId` will be\n     * transferred to `to`.\n     * - When `from` is zero, `tokenId` will be minted for `to`.\n     * - When `to` is zero, ``from``\u0027s `tokenId` will be burned.\n     * - `from` and `to` are never both zero.\n     *\n     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n     */\n    function _beforeTokenTransfer(\n        address from,\n        address to,\n        uint256 tokenId\n    ) internal virtual {}\n}\n"},"ERC721Enumerable.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\nimport \"./ERC721.sol\";\nimport \"./IERC721Enumerable.sol\";\n\n/**\n * @dev This implements an optional extension of {ERC721} defined in the EIP that adds\n * enumerability of all the token ids in the contract as well as all token ids owned by each\n * account.\n */\nabstract contract ERC721Enumerable is ERC721, IERC721Enumerable {\n    // Mapping from owner to list of owned token IDs\n    mapping(address =\u003e mapping(uint256 =\u003e uint256)) private _ownedTokens;\n\n    // Mapping from token ID to index of the owner tokens list\n    mapping(uint256 =\u003e uint256) private _ownedTokensIndex;\n\n    // Array with all token ids, used for enumeration\n    uint256[] private _allTokens;\n\n    // Mapping from token id to position in the allTokens array\n    mapping(uint256 =\u003e uint256) private _allTokensIndex;\n\n    /**\n     * @dev See {IERC165-supportsInterface}.\n     */\n    function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC721) returns (bool) {\n        return interfaceId == type(IERC721Enumerable).interfaceId || super.supportsInterface(interfaceId);\n    }\n\n    /**\n     * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.\n     */\n    function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {\n        require(index \u003c ERC721.balanceOf(owner), \"ERC721Enumerable: owner index out of bounds\");\n        return _ownedTokens[owner][index];\n    }\n\n    /**\n     * @dev See {IERC721Enumerable-totalSupply}.\n     */\n    function totalSupply() public view virtual override returns (uint256) {\n        return _allTokens.length;\n    }\n\n    /**\n     * @dev See {IERC721Enumerable-tokenByIndex}.\n     */\n    function tokenByIndex(uint256 index) public view virtual override returns (uint256) {\n        require(index \u003c ERC721Enumerable.totalSupply(), \"ERC721Enumerable: global index out of bounds\");\n        return _allTokens[index];\n    }\n\n    /**\n     * @dev Hook that is called before any token transfer. This includes minting\n     * and burning.\n     *\n     * Calling conditions:\n     *\n     * - When `from` and `to` are both non-zero, ``from``\u0027s `tokenId` will be\n     * transferred to `to`.\n     * - When `from` is zero, `tokenId` will be minted for `to`.\n     * - When `to` is zero, ``from``\u0027s `tokenId` will be burned.\n     * - `from` cannot be the zero address.\n     * - `to` cannot be the zero address.\n     *\n     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n     */\n    function _beforeTokenTransfer(\n        address from,\n        address to,\n        uint256 tokenId\n    ) internal virtual override {\n        super._beforeTokenTransfer(from, to, tokenId);\n\n        if (from == address(0)) {\n            _addTokenToAllTokensEnumeration(tokenId);\n        } else if (from != to) {\n            _removeTokenFromOwnerEnumeration(from, tokenId);\n        }\n        if (to == address(0)) {\n            _removeTokenFromAllTokensEnumeration(tokenId);\n        } else if (to != from) {\n            _addTokenToOwnerEnumeration(to, tokenId);\n        }\n    }\n\n    /**\n     * @dev Private function to add a token to this extension\u0027s ownership-tracking data structures.\n     * @param to address representing the new owner of the given token ID\n     * @param tokenId uint256 ID of the token to be added to the tokens list of the given address\n     */\n    function _addTokenToOwnerEnumeration(address to, uint256 tokenId) private {\n        uint256 length = ERC721.balanceOf(to);\n        _ownedTokens[to][length] = tokenId;\n        _ownedTokensIndex[tokenId] = length;\n    }\n\n    /**\n     * @dev Private function to add a token to this extension\u0027s token tracking data structures.\n     * @param tokenId uint256 ID of the token to be added to the tokens list\n     */\n    function _addTokenToAllTokensEnumeration(uint256 tokenId) private {\n        _allTokensIndex[tokenId] = _allTokens.length;\n        _allTokens.push(tokenId);\n    }\n\n    /**\n     * @dev Private function to remove a token from this extension\u0027s ownership-tracking data structures. Note that\n     * while the token is not assigned a new owner, the `_ownedTokensIndex` mapping is _not_ updated: this allows for\n     * gas optimizations e.g. when performing a transfer operation (avoiding double writes).\n     * This has O(1) time complexity, but alters the order of the _ownedTokens array.\n     * @param from address representing the previous owner of the given token ID\n     * @param tokenId uint256 ID of the token to be removed from the tokens list of the given address\n     */\n    function _removeTokenFromOwnerEnumeration(address from, uint256 tokenId) private {\n        // To prevent a gap in from\u0027s tokens array, we store the last token in the index of the token to delete, and\n        // then delete the last slot (swap and pop).\n\n        uint256 lastTokenIndex = ERC721.balanceOf(from) - 1;\n        uint256 tokenIndex = _ownedTokensIndex[tokenId];\n\n        // When the token to delete is the last token, the swap operation is unnecessary\n        if (tokenIndex != lastTokenIndex) {\n            uint256 lastTokenId = _ownedTokens[from][lastTokenIndex];\n\n            _ownedTokens[from][tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token\n            _ownedTokensIndex[lastTokenId] = tokenIndex; // Update the moved token\u0027s index\n        }\n\n        // This also deletes the contents at the last position of the array\n        delete _ownedTokensIndex[tokenId];\n        delete _ownedTokens[from][lastTokenIndex];\n    }\n\n    /**\n     * @dev Private function to remove a token from this extension\u0027s token tracking data structures.\n     * This has O(1) time complexity, but alters the order of the _allTokens array.\n     * @param tokenId uint256 ID of the token to be removed from the tokens list\n     */\n    function _removeTokenFromAllTokensEnumeration(uint256 tokenId) private {\n        // To prevent a gap in the tokens array, we store the last token in the index of the token to delete, and\n        // then delete the last slot (swap and pop).\n\n        uint256 lastTokenIndex = _allTokens.length - 1;\n        uint256 tokenIndex = _allTokensIndex[tokenId];\n\n        // When the token to delete is the last token, the swap operation is unnecessary. However, since this occurs so\n        // rarely (when the last minted token is burnt) that we still do the swap here to avoid the gas cost of adding\n        // an \u0027if\u0027 statement (like in _removeTokenFromOwnerEnumeration)\n        uint256 lastTokenId = _allTokens[lastTokenIndex];\n\n        _allTokens[tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token\n        _allTokensIndex[lastTokenId] = tokenIndex; // Update the moved token\u0027s index\n\n        // This also deletes the contents at the last position of the array\n        delete _allTokensIndex[tokenId];\n        _allTokens.pop();\n    }\n}\n"},"IBarn.sol":{"content":"// SPDX-License-Identifier: MIT LICENSE \n\npragma solidity ^0.8.0;\n\ninterface IBarn {\n  function addManyToBarnAndPack(address account, uint16[] calldata tokenIds) external;\n  function randomWolfOwner(uint256 seed) external view returns (address);\n}"},"IERC165.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Interface of the ERC165 standard, as defined in the\n * https://eips.ethereum.org/EIPS/eip-165[EIP].\n *\n * Implementers can declare support of contract interfaces, which can then be\n * queried by others ({ERC165Checker}).\n *\n * For an implementation, see {ERC165}.\n */\ninterface IERC165 {\n    /**\n     * @dev Returns true if this contract implements the interface defined by\n     * `interfaceId`. See the corresponding\n     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]\n     * to learn more about how these ids are created.\n     *\n     * This function call must use less than 30 000 gas.\n     */\n    function supportsInterface(bytes4 interfaceId) external view returns (bool);\n}\n"},"IERC20.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Interface of the ERC20 standard as defined in the EIP.\n */\ninterface IERC20 {\n    /**\n     * @dev Returns the amount of tokens in existence.\n     */\n    function totalSupply() external view returns (uint256);\n\n    /**\n     * @dev Returns the amount of tokens owned by `account`.\n     */\n    function balanceOf(address account) external view returns (uint256);\n\n    /**\n     * @dev Moves `amount` tokens from the caller\u0027s account to `recipient`.\n     *\n     * Returns a boolean value indicating whether the operation succeeded.\n     *\n     * Emits a {Transfer} event.\n     */\n    function transfer(address recipient, uint256 amount) external returns (bool);\n\n    /**\n     * @dev Returns the remaining number of tokens that `spender` will be\n     * allowed to spend on behalf of `owner` through {transferFrom}. This is\n     * zero by default.\n     *\n     * This value changes when {approve} or {transferFrom} are called.\n     */\n    function allowance(address owner, address spender) external view returns (uint256);\n\n    /**\n     * @dev Sets `amount` as the allowance of `spender` over the caller\u0027s tokens.\n     *\n     * Returns a boolean value indicating whether the operation succeeded.\n     *\n     * IMPORTANT: Beware that changing an allowance with this method brings the risk\n     * that someone may use both the old and the new allowance by unfortunate\n     * transaction ordering. One possible solution to mitigate this race\n     * condition is to first reduce the spender\u0027s allowance to 0 and set the\n     * desired value afterwards:\n     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729\n     *\n     * Emits an {Approval} event.\n     */\n    function approve(address spender, uint256 amount) external returns (bool);\n\n    /**\n     * @dev Moves `amount` tokens from `sender` to `recipient` using the\n     * allowance mechanism. `amount` is then deducted from the caller\u0027s\n     * allowance.\n     *\n     * Returns a boolean value indicating whether the operation succeeded.\n     *\n     * Emits a {Transfer} event.\n     */\n    function transferFrom(\n        address sender,\n        address recipient,\n        uint256 amount\n    ) external returns (bool);\n\n    /**\n     * @dev Emitted when `value` tokens are moved from one account (`from`) to\n     * another (`to`).\n     *\n     * Note that `value` may be zero.\n     */\n    event Transfer(address indexed from, address indexed to, uint256 value);\n\n    /**\n     * @dev Emitted when the allowance of a `spender` for an `owner` is set by\n     * a call to {approve}. `value` is the new allowance.\n     */\n    event Approval(address indexed owner, address indexed spender, uint256 value);\n}\n"},"IERC20Metadata.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\nimport \"./IERC20.sol\";\n\n/**\n * @dev Interface for the optional metadata functions from the ERC20 standard.\n *\n * _Available since v4.1._\n */\ninterface IERC20Metadata is IERC20 {\n    /**\n     * @dev Returns the name of the token.\n     */\n    function name() external view returns (string memory);\n\n    /**\n     * @dev Returns the symbol of the token.\n     */\n    function symbol() external view returns (string memory);\n\n    /**\n     * @dev Returns the decimals places of the token.\n     */\n    function decimals() external view returns (uint8);\n}\n"},"IERC721.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\nimport \"./IERC165.sol\";\n\n/**\n * @dev Required interface of an ERC721 compliant contract.\n */\ninterface IERC721 is IERC165 {\n    /**\n     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.\n     */\n    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);\n\n    /**\n     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.\n     */\n    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);\n\n    /**\n     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.\n     */\n    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);\n\n    /**\n     * @dev Returns the number of tokens in ``owner``\u0027s account.\n     */\n    function balanceOf(address owner) external view returns (uint256 balance);\n\n    /**\n     * @dev Returns the owner of the `tokenId` token.\n     *\n     * Requirements:\n     *\n     * - `tokenId` must exist.\n     */\n    function ownerOf(uint256 tokenId) external view returns (address owner);\n\n    /**\n     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients\n     * are aware of the ERC721 protocol to prevent tokens from being forever locked.\n     *\n     * Requirements:\n     *\n     * - `from` cannot be the zero address.\n     * - `to` cannot be the zero address.\n     * - `tokenId` token must exist and be owned by `from`.\n     * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.\n     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n     *\n     * Emits a {Transfer} event.\n     */\n    function safeTransferFrom(\n        address from,\n        address to,\n        uint256 tokenId\n    ) external;\n\n    /**\n     * @dev Transfers `tokenId` token from `from` to `to`.\n     *\n     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.\n     *\n     * Requirements:\n     *\n     * - `from` cannot be the zero address.\n     * - `to` cannot be the zero address.\n     * - `tokenId` token must be owned by `from`.\n     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.\n     *\n     * Emits a {Transfer} event.\n     */\n    function transferFrom(\n        address from,\n        address to,\n        uint256 tokenId\n    ) external;\n\n    /**\n     * @dev Gives permission to `to` to transfer `tokenId` token to another account.\n     * The approval is cleared when the token is transferred.\n     *\n     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.\n     *\n     * Requirements:\n     *\n     * - The caller must own the token or be an approved operator.\n     * - `tokenId` must exist.\n     *\n     * Emits an {Approval} event.\n     */\n    function approve(address to, uint256 tokenId) external;\n\n    /**\n     * @dev Returns the account approved for `tokenId` token.\n     *\n     * Requirements:\n     *\n     * - `tokenId` must exist.\n     */\n    function getApproved(uint256 tokenId) external view returns (address operator);\n\n    /**\n     * @dev Approve or remove `operator` as an operator for the caller.\n     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.\n     *\n     * Requirements:\n     *\n     * - The `operator` cannot be the caller.\n     *\n     * Emits an {ApprovalForAll} event.\n     */\n    function setApprovalForAll(address operator, bool _approved) external;\n\n    /**\n     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.\n     *\n     * See {setApprovalForAll}\n     */\n    function isApprovedForAll(address owner, address operator) external view returns (bool);\n\n    /**\n     * @dev Safely transfers `tokenId` token from `from` to `to`.\n     *\n     * Requirements:\n     *\n     * - `from` cannot be the zero address.\n     * - `to` cannot be the zero address.\n     * - `tokenId` token must exist and be owned by `from`.\n     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.\n     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n     *\n     * Emits a {Transfer} event.\n     */\n    function safeTransferFrom(\n        address from,\n        address to,\n        uint256 tokenId,\n        bytes calldata data\n    ) external;\n}\n"},"IERC721Enumerable.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\nimport \"./IERC721.sol\";\n\n/**\n * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension\n * @dev See https://eips.ethereum.org/EIPS/eip-721\n */\ninterface IERC721Enumerable is IERC721 {\n    /**\n     * @dev Returns the total amount of tokens stored by the contract.\n     */\n    function totalSupply() external view returns (uint256);\n\n    /**\n     * @dev Returns a token ID owned by `owner` at a given `index` of its token list.\n     * Use along with {balanceOf} to enumerate all of ``owner``\u0027s tokens.\n     */\n    function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId);\n\n    /**\n     * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.\n     * Use along with {totalSupply} to enumerate all tokens.\n     */\n    function tokenByIndex(uint256 index) external view returns (uint256);\n}\n"},"IERC721Metadata.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\nimport \"./IERC721.sol\";\n\n/**\n * @title ERC-721 Non-Fungible Token Standard, optional metadata extension\n * @dev See https://eips.ethereum.org/EIPS/eip-721\n */\ninterface IERC721Metadata is IERC721 {\n    /**\n     * @dev Returns the token collection name.\n     */\n    function name() external view returns (string memory);\n\n    /**\n     * @dev Returns the token collection symbol.\n     */\n    function symbol() external view returns (string memory);\n\n    /**\n     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.\n     */\n    function tokenURI(uint256 tokenId) external view returns (string memory);\n}\n"},"IERC721Receiver.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\n/**\n * @title ERC721 token receiver interface\n * @dev Interface for any contract that wants to support safeTransfers\n * from ERC721 asset contracts.\n */\ninterface IERC721Receiver {\n    /**\n     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}\n     * by `operator` from `from`, this function is called.\n     *\n     * It must return its Solidity selector to confirm the token transfer.\n     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.\n     *\n     * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.\n     */\n    function onERC721Received(\n        address operator,\n        address from,\n        uint256 tokenId,\n        bytes calldata data\n    ) external returns (bytes4);\n}\n"},"ITraits.sol":{"content":"// SPDX-License-Identifier: MIT LICENSE \n\npragma solidity ^0.8.0;\n\ninterface ITraits {\n  function tokenURI(uint256 tokenId) external view returns (string memory);\n}"},"IWoolf.sol":{"content":"// SPDX-License-Identifier: MIT LICENSE\n\npragma solidity ^0.8.0;\n\ninterface IWoolf {\n\n  // struct to store each token\u0027s traits\n  struct SheepWolf {\n    bool isSheep;\n    uint8 fur;\n    uint8 head;\n    uint8 ears;\n    uint8 eyes;\n    uint8 nose;\n    uint8 mouth;\n    uint8 neck;\n    uint8 feet;\n    uint8 alphaIndex;\n  }\n\n\n  function getPaidTokens() external view returns (uint256);\n  function getTokenTraits(uint256 tokenId) external view returns (SheepWolf memory);\n}"},"Ownable.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\nimport \"./Context.sol\";\n\n/**\n * @dev Contract module which provides a basic access control mechanism, where\n * there is an account (an owner) that can be granted exclusive access to\n * specific functions.\n *\n * By default, the owner account will be the one that deploys the contract. This\n * can later be changed with {transferOwnership}.\n *\n * This module is used through inheritance. It will make available the modifier\n * `onlyOwner`, which can be applied to your functions to restrict their use to\n * the owner.\n */\nabstract contract Ownable is Context {\n    address private _owner;\n\n    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);\n\n    /**\n     * @dev Initializes the contract setting the deployer as the initial owner.\n     */\n    constructor() {\n        _setOwner(_msgSender());\n    }\n\n    /**\n     * @dev Returns the address of the current owner.\n     */\n    function owner() public view virtual returns (address) {\n        return _owner;\n    }\n\n    /**\n     * @dev Throws if called by any account other than the owner.\n     */\n    modifier onlyOwner() {\n        require(owner() == _msgSender(), \"Ownable: caller is not the owner\");\n        _;\n    }\n\n    /**\n     * @dev Leaves the contract without owner. It will not be possible to call\n     * `onlyOwner` functions anymore. Can only be called by the current owner.\n     *\n     * NOTE: Renouncing ownership will leave the contract without an owner,\n     * thereby removing any functionality that is only available to the owner.\n     */\n    function renounceOwnership() public virtual onlyOwner {\n        _setOwner(address(0));\n    }\n\n    /**\n     * @dev Transfers ownership of the contract to a new account (`newOwner`).\n     * Can only be called by the current owner.\n     */\n    function transferOwnership(address newOwner) public virtual onlyOwner {\n        require(newOwner != address(0), \"Ownable: new owner is the zero address\");\n        _setOwner(newOwner);\n    }\n\n    function _setOwner(address newOwner) private {\n        address oldOwner = _owner;\n        _owner = newOwner;\n        emit OwnershipTransferred(oldOwner, newOwner);\n    }\n}\n"},"Pausable.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\nimport \"./Context.sol\";\n\n/**\n * @dev Contract module which allows children to implement an emergency stop\n * mechanism that can be triggered by an authorized account.\n *\n * This module is used through inheritance. It will make available the\n * modifiers `whenNotPaused` and `whenPaused`, which can be applied to\n * the functions of your contract. Note that they will not be pausable by\n * simply including this module, only once the modifiers are put in place.\n */\nabstract contract Pausable is Context {\n    /**\n     * @dev Emitted when the pause is triggered by `account`.\n     */\n    event Paused(address account);\n\n    /**\n     * @dev Emitted when the pause is lifted by `account`.\n     */\n    event Unpaused(address account);\n\n    bool private _paused;\n\n    /**\n     * @dev Initializes the contract in unpaused state.\n     */\n    constructor() {\n        _paused = false;\n    }\n\n    /**\n     * @dev Returns true if the contract is paused, and false otherwise.\n     */\n    function paused() public view virtual returns (bool) {\n        return _paused;\n    }\n\n    /**\n     * @dev Modifier to make a function callable only when the contract is not paused.\n     *\n     * Requirements:\n     *\n     * - The contract must not be paused.\n     */\n    modifier whenNotPaused() {\n        require(!paused(), \"Pausable: paused\");\n        _;\n    }\n\n    /**\n     * @dev Modifier to make a function callable only when the contract is paused.\n     *\n     * Requirements:\n     *\n     * - The contract must be paused.\n     */\n    modifier whenPaused() {\n        require(paused(), \"Pausable: not paused\");\n        _;\n    }\n\n    /**\n     * @dev Triggers stopped state.\n     *\n     * Requirements:\n     *\n     * - The contract must not be paused.\n     */\n    function _pause() internal virtual whenNotPaused {\n        _paused = true;\n        emit Paused(_msgSender());\n    }\n\n    /**\n     * @dev Returns to normal state.\n     *\n     * Requirements:\n     *\n     * - The contract must be paused.\n     */\n    function _unpause() internal virtual whenPaused {\n        _paused = false;\n        emit Unpaused(_msgSender());\n    }\n}\n"},"Strings.sol":{"content":"// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\n/**\n * @dev String operations.\n */\nlibrary Strings {\n    bytes16 private constant _HEX_SYMBOLS = \"0123456789abcdef\";\n\n    /**\n     * @dev Converts a `uint256` to its ASCII `string` decimal representation.\n     */\n    function toString(uint256 value) internal pure returns (string memory) {\n        // Inspired by OraclizeAPI\u0027s implementation - MIT licence\n        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol\n\n        if (value == 0) {\n            return \"0\";\n        }\n        uint256 temp = value;\n        uint256 digits;\n        while (temp != 0) {\n            digits++;\n            temp /= 10;\n        }\n        bytes memory buffer = new bytes(digits);\n        while (value != 0) {\n            digits -= 1;\n            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));\n            value /= 10;\n        }\n        return string(buffer);\n    }\n\n    /**\n     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.\n     */\n    function toHexString(uint256 value) internal pure returns (string memory) {\n        if (value == 0) {\n            return \"0x00\";\n        }\n        uint256 temp = value;\n        uint256 length = 0;\n        while (temp != 0) {\n            length++;\n            temp \u003e\u003e= 8;\n        }\n        return toHexString(value, length);\n    }\n\n    /**\n     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.\n     */\n    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {\n        bytes memory buffer = new bytes(2 * length + 2);\n        buffer[0] = \"0\";\n        buffer[1] = \"x\";\n        for (uint256 i = 2 * length + 1; i \u003e 1; --i) {\n            buffer[i] = _HEX_SYMBOLS[value \u0026 0xf];\n            value \u003e\u003e= 4;\n        }\n        require(value == 0, \"Strings: hex length insufficient\");\n        return string(buffer);\n    }\n}\n"},"Traits.sol":{"content":"// SPDX-License-Identifier: MIT LICENSE\n\npragma solidity ^0.8.0;\nimport \"./Ownable.sol\";\nimport \"./Strings.sol\";\nimport \"./ITraits.sol\";\nimport \"./IWoolf.sol\";\n\ncontract Traits is Ownable, ITraits {\n\n  using Strings for uint256;\n\n  // struct to store each trait\u0027s data for metadata and rendering\n  struct Trait {\n    string name;\n    string png;\n  }\n\n  // mapping from trait type (index) to its name\n  string[9] _traitTypes = [\n    \"Fur\",\n    \"Head\",\n    \"Ears\",\n    \"Eyes\",\n    \"Nose\",\n    \"Mouth\",\n    \"Neck\",\n    \"Feet\",\n    \"Alpha\"\n  ];\n  // storage of each traits name and base64 PNG data\n  mapping(uint8 =\u003e mapping(uint8 =\u003e Trait)) public traitData;\n  // mapping from alphaIndex to its score\n  string[4] _alphas = [\n    \"8\",\n    \"7\",\n    \"6\",\n    \"5\"\n  ];\n\n  IWoolf public woolf;\n\n  constructor() {}\n\n  /** ADMIN */\n\n  function setWoolf(address _woolf) external onlyOwner {\n    woolf = IWoolf(_woolf);\n  }\n\n  /**\n   * administrative to upload the names and images associated with each trait\n   * @param traitType the trait type to upload the traits for (see traitTypes for a mapping)\n   * @param traits the names and base64 encoded PNGs for each trait\n   */\n  function uploadTraits(uint8 traitType, uint8[] calldata traitIds, Trait[] calldata traits) external onlyOwner {\n    require(traitIds.length == traits.length, \"Mismatched inputs\");\n    for (uint i = 0; i \u003c traits.length; i++) {\n      traitData[traitType][traitIds[i]] = Trait(\n        traits[i].name,\n        traits[i].png\n      );\n    }\n  }\n\n  /** RENDER */\n\n  /**\n   * generates an \u003cimage\u003e element using base64 encoded PNGs\n   * @param trait the trait storing the PNG data\n   * @return the \u003cimage\u003e element\n   */\n  function drawTrait(Trait memory trait) internal pure returns (string memory) {\n    return string(abi.encodePacked(\n      \u0027\u003cimage x=\"4\" y=\"4\" width=\"32\" height=\"32\" image-rendering=\"pixelated\" preserveAspectRatio=\"xMidYMid\" xlink:href=\"data:image/png;base64,\u0027,\n      trait.png,\n      \u0027\"/\u003e\u0027\n    ));\n  }\n\n  /**\n   * generates an entire SVG by composing multiple \u003cimage\u003e elements of PNGs\n   * @param tokenId the ID of the token to generate an SVG for\n   * @return a valid SVG of the Sheep / Wolf\n   */\n  function drawSVG(uint256 tokenId) public view returns (string memory) {\n    IWoolf.SheepWolf memory s = woolf.getTokenTraits(tokenId);\n    uint8 shift = s.isSheep ? 0 : 9;\n\n    string memory svgString = string(abi.encodePacked(\n      drawTrait(traitData[0 + shift][s.fur]),\n      s.isSheep ? drawTrait(traitData[1 + shift][s.head]) : drawTrait(traitData[1 + shift][s.alphaIndex]),\n      s.isSheep ? drawTrait(traitData[2 + shift][s.ears]) : \u0027\u0027,\n      drawTrait(traitData[3 + shift][s.eyes]),\n      s.isSheep ? drawTrait(traitData[4 + shift][s.nose]) : \u0027\u0027,\n      drawTrait(traitData[5 + shift][s.mouth]),\n      s.isSheep ? \u0027\u0027 : drawTrait(traitData[6 + shift][s.neck]),\n      s.isSheep ? drawTrait(traitData[7 + shift][s.feet]) : \u0027\u0027\n    ));\n\n    return string(abi.encodePacked(\n      \u0027\u003csvg id=\"woolf\" width=\"100%\" height=\"100%\" version=\"1.1\" viewBox=\"0 0 40 40\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"\u003e\u0027,\n      svgString,\n      \"\u003c/svg\u003e\"\n    ));\n  }\n\n  /**\n   * generates an attribute for the attributes array in the ERC721 metadata standard\n   * @param traitType the trait type to reference as the metadata key\n   * @param value the token\u0027s trait associated with the key\n   * @return a JSON dictionary for the single attribute\n   */\n  function attributeForTypeAndValue(string memory traitType, string memory value) internal pure returns (string memory) {\n    return string(abi.encodePacked(\n      \u0027{\"trait_type\":\"\u0027,\n      traitType,\n      \u0027\",\"value\":\"\u0027,\n      value,\n      \u0027\"}\u0027\n    ));\n  }\n\n  /**\n   * generates an array composed of all the individual traits and values\n   * @param tokenId the ID of the token to compose the metadata for\n   * @return a JSON array of all of the attributes for given token ID\n   */\n  function compileAttributes(uint256 tokenId) public view returns (string memory) {\n    IWoolf.SheepWolf memory s = woolf.getTokenTraits(tokenId);\n    string memory traits;\n    if (s.isSheep) {\n      traits = string(abi.encodePacked(\n        attributeForTypeAndValue(_traitTypes[0], traitData[0][s.fur].name),\u0027,\u0027,\n        attributeForTypeAndValue(_traitTypes[1], traitData[1][s.head].name),\u0027,\u0027,\n        attributeForTypeAndValue(_traitTypes[2], traitData[2][s.ears].name),\u0027,\u0027,\n        attributeForTypeAndValue(_traitTypes[3], traitData[3][s.eyes].name),\u0027,\u0027,\n        attributeForTypeAndValue(_traitTypes[4], traitData[4][s.nose].name),\u0027,\u0027,\n        attributeForTypeAndValue(_traitTypes[5], traitData[5][s.mouth].name),\u0027,\u0027,\n        attributeForTypeAndValue(_traitTypes[7], traitData[7][s.feet].name),\u0027,\u0027\n      ));\n    } else {\n      traits = string(abi.encodePacked(\n        attributeForTypeAndValue(_traitTypes[0], traitData[9][s.fur].name),\u0027,\u0027,\n        attributeForTypeAndValue(_traitTypes[1], traitData[10][s.alphaIndex].name),\u0027,\u0027,\n        attributeForTypeAndValue(_traitTypes[3], traitData[12][s.eyes].name),\u0027,\u0027,\n        attributeForTypeAndValue(_traitTypes[5], traitData[14][s.mouth].name),\u0027,\u0027,\n        attributeForTypeAndValue(_traitTypes[6], traitData[15][s.neck].name),\u0027,\u0027,\n        attributeForTypeAndValue(\"Alpha Score\", _alphas[s.alphaIndex]),\u0027,\u0027\n      ));\n    }\n    return string(abi.encodePacked(\n      \u0027[\u0027,\n      traits,\n      \u0027{\"trait_type\":\"Generation\",\"value\":\u0027,\n      tokenId \u003c= woolf.getPaidTokens() ? \u0027\"Gen 0\"\u0027 : \u0027\"Gen 1\"\u0027,\n      \u0027},{\"trait_type\":\"Type\",\"value\":\u0027,\n      s.isSheep ? \u0027\"Sheep\"\u0027 : \u0027\"Wolf\"\u0027,\n      \u0027}]\u0027\n    ));\n  }\n\n  /**\n   * generates a base64 encoded metadata response without referencing off-chain content\n   * @param tokenId the ID of the token to generate the metadata for\n   * @return a base64 encoded JSON dictionary of the token\u0027s metadata and SVG\n   */\n  function tokenURI(uint256 tokenId) public view override returns (string memory) {\n    IWoolf.SheepWolf memory s = woolf.getTokenTraits(tokenId);\n\n    string memory metadata = string(abi.encodePacked(\n      \u0027{\"name\": \"\u0027,\n      s.isSheep ? \u0027Sheep #\u0027 : \u0027Wolf #\u0027,\n      tokenId.toString(),\n      \u0027\", \"description\": \"Thousands of Sheep and Wolves compete on a farm in the metaverse. A tempting prize of $WOOL awaits, with deadly high stakes. All the metadata and images are generated and stored 100% on-chain. No IPFS. NO API. Just the Ethereum blockchain.\", \"image\": \"data:image/svg+xml;base64,\u0027,\n      base64(bytes(drawSVG(tokenId))),\n      \u0027\", \"attributes\":\u0027,\n      compileAttributes(tokenId),\n      \"}\"\n    ));\n\n    return string(abi.encodePacked(\n      \"data:application/json;base64,\",\n      base64(bytes(metadata))\n    ));\n  }\n\n  /** BASE 64 - Written by Brech Devos */\n  \n  string internal constant TABLE = \u0027ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/\u0027;\n\n  function base64(bytes memory data) internal pure returns (string memory) {\n    if (data.length == 0) return \u0027\u0027;\n    \n    // load the table into memory\n    string memory table = TABLE;\n\n    // multiply by 4/3 rounded up\n    uint256 encodedLen = 4 * ((data.length + 2) / 3);\n\n    // add some extra buffer at the end required for the writing\n    string memory result = new string(encodedLen + 32);\n\n    assembly {\n      // set the actual output length\n      mstore(result, encodedLen)\n      \n      // prepare the lookup table\n      let tablePtr := add(table, 1)\n      \n      // input ptr\n      let dataPtr := data\n      let endPtr := add(dataPtr, mload(data))\n      \n      // result ptr, jump over length\n      let resultPtr := add(result, 32)\n      \n      // run over the input, 3 bytes at a time\n      for {} lt(dataPtr, endPtr) {}\n      {\n          dataPtr := add(dataPtr, 3)\n          \n          // read 3 bytes\n          let input := mload(dataPtr)\n          \n          // write 4 characters\n          mstore(resultPtr, shl(248, mload(add(tablePtr, and(shr(18, input), 0x3F)))))\n          resultPtr := add(resultPtr, 1)\n          mstore(resultPtr, shl(248, mload(add(tablePtr, and(shr(12, input), 0x3F)))))\n          resultPtr := add(resultPtr, 1)\n          mstore(resultPtr, shl(248, mload(add(tablePtr, and(shr( 6, input), 0x3F)))))\n          resultPtr := add(resultPtr, 1)\n          mstore(resultPtr, shl(248, mload(add(tablePtr, and(        input,  0x3F)))))\n          resultPtr := add(resultPtr, 1)\n      }\n      \n      // padding with \u0027=\u0027\n      switch mod(mload(data), 3)\n      case 1 { mstore(sub(resultPtr, 2), shl(240, 0x3d3d)) }\n      case 2 { mstore(sub(resultPtr, 1), shl(248, 0x3d)) }\n    }\n    \n    return result;\n  }\n}"},"WOOL.sol":{"content":"// SPDX-License-Identifier: MIT LICENSE\n\npragma solidity ^0.8.0;\nimport \"./ERC20.sol\";\nimport \"./Ownable.sol\";\n\ncontract WOOL is ERC20, Ownable {\n\n  // a mapping from an address to whether or not it can mint / burn\n  mapping(address =\u003e bool) controllers;\n  \n  constructor() ERC20(\"WOOL\", \"WOOL\") { }\n\n  /**\n   * mints $WOOL to a recipient\n   * @param to the recipient of the $WOOL\n   * @param amount the amount of $WOOL to mint\n   */\n  function mint(address to, uint256 amount) external {\n    require(controllers[msg.sender], \"Only controllers can mint\");\n    _mint(to, amount);\n  }\n\n  /**\n   * burns $WOOL from a holder\n   * @param from the holder of the $WOOL\n   * @param amount the amount of $WOOL to burn\n   */\n  function burn(address from, uint256 amount) external {\n    require(controllers[msg.sender], \"Only controllers can burn\");\n    _burn(from, amount);\n  }\n\n  /**\n   * enables an address to mint / burn\n   * @param controller the address to enable\n   */\n  function addController(address controller) external onlyOwner {\n    controllers[controller] = true;\n  }\n\n  /**\n   * disables an address from minting / burning\n   * @param controller the address to disbale\n   */\n  function removeController(address controller) external onlyOwner {\n    controllers[controller] = false;\n  }\n}"},"Woolf.sol":{"content":"// SPDX-License-Identifier: MIT LICENSE\n\npragma solidity ^0.8.0;\nimport \"./Ownable.sol\";\nimport \"./Pausable.sol\";\nimport \"./ERC721Enumerable.sol\";\nimport \"./IWoolf.sol\";\nimport \"./IBarn.sol\";\nimport \"./ITraits.sol\";\nimport \"./WOOL.sol\";\n\n\ncontract Woolf is IWoolf, ERC721Enumerable, Ownable, Pausable {\n\n  // mint price\n  uint256 public constant MINT_PRICE = .069420 ether;\n  // max number of tokens that can be minted - 50000 in production\n  uint256 public immutable MAX_TOKENS;\n  // number of tokens that can be claimed for free - 20% of MAX_TOKENS\n  uint256 public PAID_TOKENS;\n  // number of tokens have been minted so far\n  uint16 public minted;\n\n  // mapping from tokenId to a struct containing the token\u0027s traits\n  mapping(uint256 =\u003e SheepWolf) public tokenTraits;\n  // mapping from hashed(tokenTrait) to the tokenId it\u0027s associated with\n  // used to ensure there are no duplicates\n  mapping(uint256 =\u003e uint256) public existingCombinations;\n\n  // list of probabilities for each trait type\n  // 0 - 9 are associated with Sheep, 10 - 18 are associated with Wolves\n  uint8[][18] public rarities;\n  // list of aliases for Walker\u0027s Alias algorithm\n  // 0 - 9 are associated with Sheep, 10 - 18 are associated with Wolves\n  uint8[][18] public aliases;\n\n  // reference to the Barn for choosing random Wolf thieves\n  IBarn public barn;\n  // reference to $WOOL for burning on mint\n  WOOL public wool;\n  // reference to Traits\n  ITraits public traits;\n\n  /** \n   * instantiates contract and rarity tables\n   */\n  constructor(address _wool, address _traits, uint256 _maxTokens) ERC721(\"Wolf Game\", \u0027WGAME\u0027) { \n    wool = WOOL(_wool);\n    traits = ITraits(_traits);\n    MAX_TOKENS = _maxTokens;\n    PAID_TOKENS = _maxTokens / 5;\n\n    // I know this looks weird but it saves users gas by making lookup O(1)\n    // A.J. Walker\u0027s Alias Algorithm\n    // sheep\n    // fur\n    rarities[0] = [15, 50, 200, 250, 255];\n    aliases[0] = [4, 4, 4, 4, 4];\n    // head\n    rarities[1] = [190, 215, 240, 100, 110, 135, 160, 185, 80, 210, 235, 240, 80, 80, 100, 100, 100, 245, 250, 255];\n    aliases[1] = [1, 2, 4, 0, 5, 6, 7, 9, 0, 10, 11, 17, 0, 0, 0, 0, 4, 18, 19, 19];\n    // ears\n    rarities[2] =  [255, 30, 60, 60, 150, 156];\n    aliases[2] = [0, 0, 0, 0, 0, 0];\n    // eyes\n    rarities[3] = [221, 100, 181, 140, 224, 147, 84, 228, 140, 224, 250, 160, 241, 207, 173, 84, 254, 220, 196, 140, 168, 252, 140, 183, 236, 252, 224, 255];\n    aliases[3] = [1, 2, 5, 0, 1, 7, 1, 10, 5, 10, 11, 12, 13, 14, 16, 11, 17, 23, 13, 14, 17, 23, 23, 24, 27, 27, 27, 27];\n    // nose\n    rarities[4] = [175, 100, 40, 250, 115, 100, 185, 175, 180, 255];\n    aliases[4] = [3, 0, 4, 6, 6, 7, 8, 8, 9, 9];\n    // mouth\n    rarities[5] = [80, 225, 227, 228, 112, 240, 64, 160, 167, 217, 171, 64, 240, 126, 80, 255];\n    aliases[5] = [1, 2, 3, 8, 2, 8, 8, 9, 9, 10, 13, 10, 13, 15, 13, 15];\n    // neck\n    rarities[6] = [255];\n    aliases[6] = [0];\n    // feet\n    rarities[7] = [243, 189, 133, 133, 57, 95, 152, 135, 133, 57, 222, 168, 57, 57, 38, 114, 114, 114, 255];\n    aliases[7] = [1, 7, 0, 0, 0, 0, 0, 10, 0, 0, 11, 18, 0, 0, 0, 1, 7, 11, 18];\n    // alphaIndex\n    rarities[8] = [255];\n    aliases[8] = [0];\n\n    // wolves\n    // fur\n    rarities[9] = [210, 90, 9, 9, 9, 150, 9, 255, 9];\n    aliases[9] = [5, 0, 0, 5, 5, 7, 5, 7, 5];\n    // head\n    rarities[10] = [255];\n    aliases[10] = [0];\n    // ears\n    rarities[11] = [255];\n    aliases[11] = [0];\n    // eyes\n    rarities[12] = [135, 177, 219, 141, 183, 225, 147, 189, 231, 135, 135, 135, 135, 246, 150, 150, 156, 165, 171, 180, 186, 195, 201, 210, 243, 252, 255];\n    aliases[12] = [1, 2, 3, 4, 5, 6, 7, 8, 13, 3, 6, 14, 15, 16, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 26, 26];\n    // nose\n    rarities[13] = [255];\n    aliases[13] = [0];\n    // mouth\n    rarities[14] = [239, 244, 249, 234, 234, 234, 234, 234, 234, 234, 130, 255, 247];\n    aliases[14] = [1, 2, 11, 0, 11, 11, 11, 11, 11, 11, 11, 11, 11];\n    // neck\n    rarities[15] = [75, 180, 165, 120, 60, 150, 105, 195, 45, 225, 75, 45, 195, 120, 255];\n    aliases[15] = [1, 9, 0, 0, 0, 0, 0, 0, 0, 12, 0, 0, 14, 12, 14];\n    // feet \n    rarities[16] = [255];\n    aliases[16] = [0];\n    // alphaIndex\n    rarities[17] = [8, 160, 73, 255]; \n    aliases[17] = [2, 3, 3, 3];\n  }\n\n  /** EXTERNAL */\n\n  /** \n   * mint a token - 90% Sheep, 10% Wolves\n   * The first 20% are free to claim, the remaining cost $WOOL\n   */\n  function mint(uint256 amount, bool stake) external payable whenNotPaused {\n    require(tx.origin == _msgSender(), \"Only EOA\");\n    require(minted + amount \u003c= MAX_TOKENS, \"All tokens minted\");\n    require(amount \u003e 0 \u0026\u0026 amount \u003c= 10, \"Invalid mint amount\");\n    if (minted \u003c PAID_TOKENS) {\n      require(minted + amount \u003c= PAID_TOKENS, \"All tokens on-sale already sold\");\n      require(amount * MINT_PRICE == msg.value, \"Invalid payment amount\");\n    } else {\n      require(msg.value == 0);\n    }\n\n    uint256 totalWoolCost = 0;\n    uint16[] memory tokenIds = stake ? new uint16[](amount) : new uint16[](0);\n    uint256 seed;\n    for (uint i = 0; i \u003c amount; i++) {\n      minted++;\n      seed = random(minted);\n      generate(minted, seed);\n      address recipient = selectRecipient(seed);\n      if (!stake || recipient != _msgSender()) {\n        _safeMint(recipient, minted);\n      } else {\n        _safeMint(address(barn), minted);\n        tokenIds[i] = minted;\n      }\n      totalWoolCost += mintCost(minted);\n    }\n    \n    if (totalWoolCost \u003e 0) wool.burn(_msgSender(), totalWoolCost);\n    if (stake) barn.addManyToBarnAndPack(_msgSender(), tokenIds);\n  }\n\n  /** \n   * the first 20% are paid in ETH\n   * the next 20% are 20000 $WOOL\n   * the next 40% are 40000 $WOOL\n   * the final 20% are 80000 $WOOL\n   * @param tokenId the ID to check the cost of to mint\n   * @return the cost of the given token ID\n   */\n  function mintCost(uint256 tokenId) public view returns (uint256) {\n    if (tokenId \u003c= PAID_TOKENS) return 0;\n    if (tokenId \u003c= MAX_TOKENS * 2 / 5) return 20000 ether;\n    if (tokenId \u003c= MAX_TOKENS * 4 / 5) return 40000 ether;\n    return 80000 ether;\n  }\n\n  function transferFrom(\n    address from,\n    address to,\n    uint256 tokenId\n  ) public virtual override {\n    // Hardcode the Barn\u0027s approval so that users don\u0027t have to waste gas approving\n    if (_msgSender() != address(barn))\n      require(_isApprovedOrOwner(_msgSender(), tokenId), \"ERC721: transfer caller is not owner nor approved\");\n    _transfer(from, to, tokenId);\n  }\n\n  /** INTERNAL */\n\n  /**\n   * generates traits for a specific token, checking to make sure it\u0027s unique\n   * @param tokenId the id of the token to generate traits for\n   * @param seed a pseudorandom 256 bit number to derive traits from\n   * @return t - a struct of traits for the given token ID\n   */\n  function generate(uint256 tokenId, uint256 seed) internal returns (SheepWolf memory t) {\n    t = selectTraits(seed);\n    if (existingCombinations[structToHash(t)] == 0) {\n      tokenTraits[tokenId] = t;\n      existingCombinations[structToHash(t)] = tokenId;\n      return t;\n    }\n    return generate(tokenId, random(seed));\n  }\n\n  /**\n   * uses A.J. Walker\u0027s Alias algorithm for O(1) rarity table lookup\n   * ensuring O(1) instead of O(n) reduces mint cost by more than 50%\n   * probability \u0026 alias tables are generated off-chain beforehand\n   * @param seed portion of the 256 bit seed to remove trait correlation\n   * @param traitType the trait type to select a trait for \n   * @return the ID of the randomly selected trait\n   */\n  function selectTrait(uint16 seed, uint8 traitType) internal view returns (uint8) {\n    uint8 trait = uint8(seed) % uint8(rarities[traitType].length);\n    if (seed \u003e\u003e 8 \u003c rarities[traitType][trait]) return trait;\n    return aliases[traitType][trait];\n  }\n\n  /**\n   * the first 20% (ETH purchases) go to the minter\n   * the remaining 80% have a 10% chance to be given to a random staked wolf\n   * @param seed a random value to select a recipient from\n   * @return the address of the recipient (either the minter or the Wolf thief\u0027s owner)\n   */\n  function selectRecipient(uint256 seed) internal view returns (address) {\n    if (minted \u003c= PAID_TOKENS || ((seed \u003e\u003e 245) % 10) != 0) return _msgSender(); // top 10 bits haven\u0027t been used\n    address thief = barn.randomWolfOwner(seed \u003e\u003e 144); // 144 bits reserved for trait selection\n    if (thief == address(0x0)) return _msgSender();\n    return thief;\n  }\n\n  /**\n   * selects the species and all of its traits based on the seed value\n   * @param seed a pseudorandom 256 bit number to derive traits from\n   * @return t -  a struct of randomly selected traits\n   */\n  function selectTraits(uint256 seed) internal view returns (SheepWolf memory t) {    \n    t.isSheep = (seed \u0026 0xFFFF) % 10 != 0;\n    uint8 shift = t.isSheep ? 0 : 9;\n    seed \u003e\u003e= 16;\n    t.fur = selectTrait(uint16(seed \u0026 0xFFFF), 0 + shift);\n    seed \u003e\u003e= 16;\n    t.head = selectTrait(uint16(seed \u0026 0xFFFF), 1 + shift);\n    seed \u003e\u003e= 16;\n    t.ears = selectTrait(uint16(seed \u0026 0xFFFF), 2 + shift);\n    seed \u003e\u003e= 16;\n    t.eyes = selectTrait(uint16(seed \u0026 0xFFFF), 3 + shift);\n    seed \u003e\u003e= 16;\n    t.nose = selectTrait(uint16(seed \u0026 0xFFFF), 4 + shift);\n    seed \u003e\u003e= 16;\n    t.mouth = selectTrait(uint16(seed \u0026 0xFFFF), 5 + shift);\n    seed \u003e\u003e= 16;\n    t.neck = selectTrait(uint16(seed \u0026 0xFFFF), 6 + shift);\n    seed \u003e\u003e= 16;\n    t.feet = selectTrait(uint16(seed \u0026 0xFFFF), 7 + shift);\n    seed \u003e\u003e= 16;\n    t.alphaIndex = selectTrait(uint16(seed \u0026 0xFFFF), 8 + shift);\n  }\n\n  /**\n   * converts a struct to a 256 bit hash to check for uniqueness\n   * @param s the struct to pack into a hash\n   * @return the 256 bit hash of the struct\n   */\n  function structToHash(SheepWolf memory s) internal pure returns (uint256) {\n    return uint256(bytes32(\n      abi.encodePacked(\n        s.isSheep,\n        s.fur,\n        s.head,\n        s.eyes,\n        s.mouth,\n        s.neck,\n        s.ears,\n        s.feet,\n        s.alphaIndex\n      )\n    ));\n  }\n\n  /**\n   * generates a pseudorandom number\n   * @param seed a value ensure different outcomes for different sources in the same block\n   * @return a pseudorandom value\n   */\n  function random(uint256 seed) internal view returns (uint256) {\n    return uint256(keccak256(abi.encodePacked(\n      tx.origin,\n      blockhash(block.number - 1),\n      block.timestamp,\n      seed\n    )));\n  }\n\n  /** READ */\n\n  function getTokenTraits(uint256 tokenId) external view override returns (SheepWolf memory) {\n    return tokenTraits[tokenId];\n  }\n\n  function getPaidTokens() external view override returns (uint256) {\n    return PAID_TOKENS;\n  }\n\n  /** ADMIN */\n\n  /**\n   * called after deployment so that the contract can get random wolf thieves\n   * @param _barn the address of the Barn\n   */\n  function setBarn(address _barn) external onlyOwner {\n    barn = IBarn(_barn);\n  }\n\n  /**\n   * allows owner to withdraw funds from minting\n   */\n  function withdraw() external onlyOwner {\n    payable(owner()).transfer(address(this).balance);\n  }\n\n  /**\n   * updates the number of tokens for sale\n   */\n  function setPaidTokens(uint256 _paidTokens) external onlyOwner {\n    PAID_TOKENS = _paidTokens;\n  }\n\n  /**\n   * enables owner to pause / unpause minting\n   */\n  function setPaused(bool _paused) external onlyOwner {\n    if (_paused) _pause();\n    else _unpause();\n  }\n\n  /** RENDER */\n\n  function tokenURI(uint256 tokenId) public view override returns (string memory) {\n    require(_exists(tokenId), \"ERC721Metadata: URI query for nonexistent token\");\n    return traits.tokenURI(tokenId);\n  }\n}"}}