// File: Address.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: AddressUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (utils/Address.sol)

pragma solidity ^0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library AddressUpgradeable {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: Barn.sol



// SPDX-License-Identifier: MIT LICENSE

pragma solidity ^0.8.0;

import "./IERC721Receiver.sol";
import "./Pausable.sol";
import "./Woolf.sol";
import "./WOOL.sol";

contract Barn is Ownable, IERC721Receiver, Pausable {
  
  // maximum alpha score for a Wolf
  uint8 public constant MAX_ALPHA = 8;

  // struct to store a stake's token, owner, and earning values
  struct Stake {
    uint16 tokenId;
    uint80 value;
    address owner;
  }

  event TokenStaked(address owner, uint256 tokenId, uint256 value);
  event SheepClaimed(uint256 tokenId, uint256 earned, bool unstaked);
  event WolfClaimed(uint256 tokenId, uint256 earned, bool unstaked);

  // reference to the Woolf NFT contract
  Woolf woolf;
  // reference to the $WOOL contract for minting $WOOL earnings
  WOOL wool;

  // maps tokenId to stake
  mapping(uint256 => Stake) public barn; 
  // maps alpha to all Wolf stakes with that alpha
  mapping(uint256 => Stake[]) public pack; 
  // tracks location of each Wolf in Pack
  mapping(uint256 => uint256) public packIndices; 
  // total alpha scores staked
  uint256 public totalAlphaStaked = 0; 
  // any rewards distributed when no wolves are staked
  uint256 public unaccountedRewards = 0; 
  // amount of $WOOL due for each alpha point staked
  uint256 public woolPerAlpha = 0; 

  // sheep earn 10000 $WOOL per day
  uint256 public constant DAILY_WOOL_RATE = 10000 ether;
  // sheep must have 2 days worth of $WOOL to unstake or else it's too cold
  uint256 public constant MINIMUM_TO_EXIT = 2 days;
  // wolves take a 20% tax on all $WOOL claimed
  uint256 public constant WOOL_CLAIM_TAX_PERCENTAGE = 20;
  // there will only ever be (roughly) 2.4 billion $WOOL earned through staking
  uint256 public constant MAXIMUM_GLOBAL_WOOL = 2400000000 ether;

  // amount of $WOOL earned so far
  uint256 public totalWoolEarned;
  // number of Sheep staked in the Barn
  uint256 public totalSheepStaked;
  // the last time $WOOL was claimed
  uint256 public lastClaimTimestamp;

  // emergency rescue to allow unstaking without any checks but without $WOOL
  bool public rescueEnabled = false;

  /**
   * @param _woolf reference to the Woolf NFT contract
   * @param _wool reference to the $WOOL token
   */
  constructor(address _woolf, address _wool) { 
    woolf = Woolf(_woolf);
    wool = WOOL(_wool);
  }

  /** STAKING */

  /**
   * adds Sheep and Wolves to the Barn and Pack
   * @param account the address of the staker
   * @param tokenIds the IDs of the Sheep and Wolves to stake
   */
  function addManyToBarnAndPack(address account, uint16[] calldata tokenIds) external {
    require(account == _msgSender() || _msgSender() == address(woolf), "DONT GIVE YOUR TOKENS AWAY");
    for (uint i = 0; i < tokenIds.length; i++) {
      if (_msgSender() != address(woolf)) { // dont do this step if its a mint + stake
        require(woolf.ownerOf(tokenIds[i]) == _msgSender(), "AINT YO TOKEN");
        woolf.transferFrom(_msgSender(), address(this), tokenIds[i]);
      } else if (tokenIds[i] == 0) {
        continue; // there may be gaps in the array for stolen tokens
      }

      if (isSheep(tokenIds[i])) 
        _addSheepToBarn(account, tokenIds[i]);
      else 
        _addWolfToPack(account, tokenIds[i]);
    }
  }

  /**
   * adds a single Sheep to the Barn
   * @param account the address of the staker
   * @param tokenId the ID of the Sheep to add to the Barn
   */
  function _addSheepToBarn(address account, uint256 tokenId) internal whenNotPaused _updateEarnings {
    barn[tokenId] = Stake({
      owner: account,
      tokenId: uint16(tokenId),
      value: uint80(block.timestamp)
    });
    totalSheepStaked += 1;
    emit TokenStaked(account, tokenId, block.timestamp);
  }

  /**
   * adds a single Wolf to the Pack
   * @param account the address of the staker
   * @param tokenId the ID of the Wolf to add to the Pack
   */
  function _addWolfToPack(address account, uint256 tokenId) internal {
    uint256 alpha = _alphaForWolf(tokenId);
    totalAlphaStaked += alpha; // Portion of earnings ranges from 8 to 5
    packIndices[tokenId] = pack[alpha].length; // Store the location of the wolf in the Pack
    pack[alpha].push(Stake({
      owner: account,
      tokenId: uint16(tokenId),
      value: uint80(woolPerAlpha)
    })); // Add the wolf to the Pack
    emit TokenStaked(account, tokenId, woolPerAlpha);
  }

  /** CLAIMING / UNSTAKING */

  /**
   * realize $WOOL earnings and optionally unstake tokens from the Barn / Pack
   * to unstake a Sheep it will require it has 2 days worth of $WOOL unclaimed
   * @param tokenIds the IDs of the tokens to claim earnings from
   * @param unstake whether or not to unstake ALL of the tokens listed in tokenIds
   */
  function claimManyFromBarnAndPack(uint16[] calldata tokenIds, bool unstake) external whenNotPaused _updateEarnings {
    uint256 owed = 0;
    for (uint i = 0; i < tokenIds.length; i++) {
      if (isSheep(tokenIds[i]))
        owed += _claimSheepFromBarn(tokenIds[i], unstake);
      else
        owed += _claimWolfFromPack(tokenIds[i], unstake);
    }
    if (owed == 0) return;
    wool.mint(_msgSender(), owed);
  }

  /**
   * realize $WOOL earnings for a single Sheep and optionally unstake it
   * if not unstaking, pay a 20% tax to the staked Wolves
   * if unstaking, there is a 50% chance all $WOOL is stolen
   * @param tokenId the ID of the Sheep to claim earnings from
   * @param unstake whether or not to unstake the Sheep
   * @return owed - the amount of $WOOL earned
   */
  function _claimSheepFromBarn(uint256 tokenId, bool unstake) internal returns (uint256 owed) {
    Stake memory stake = barn[tokenId];
    require(stake.owner == _msgSender(), "SWIPER, NO SWIPING");
    require(!(unstake && block.timestamp - stake.value < MINIMUM_TO_EXIT), "GONNA BE COLD WITHOUT TWO DAY'S WOOL");
    if (totalWoolEarned < MAXIMUM_GLOBAL_WOOL) {
      owed = (block.timestamp - stake.value) * DAILY_WOOL_RATE / 1 days;
    } else if (stake.value > lastClaimTimestamp) {
      owed = 0; // $WOOL production stopped already
    } else {
      owed = (lastClaimTimestamp - stake.value) * DAILY_WOOL_RATE / 1 days; // stop earning additional $WOOL if it's all been earned
    }
    if (unstake) {
      if (random(tokenId) & 1 == 1) { // 50% chance of all $WOOL stolen
        _payWolfTax(owed);
        owed = 0;
      }
      woolf.safeTransferFrom(address(this), _msgSender(), tokenId, ""); // send back Sheep
      delete barn[tokenId];
      totalSheepStaked -= 1;
    } else {
      _payWolfTax(owed * WOOL_CLAIM_TAX_PERCENTAGE / 100); // percentage tax to staked wolves
      owed = owed * (100 - WOOL_CLAIM_TAX_PERCENTAGE) / 100; // remainder goes to Sheep owner
      barn[tokenId] = Stake({
        owner: _msgSender(),
        tokenId: uint16(tokenId),
        value: uint80(block.timestamp)
      }); // reset stake
    }
    emit SheepClaimed(tokenId, owed, unstake);
  }

  /**
   * realize $WOOL earnings for a single Wolf and optionally unstake it
   * Wolves earn $WOOL proportional to their Alpha rank
   * @param tokenId the ID of the Wolf to claim earnings from
   * @param unstake whether or not to unstake the Wolf
   * @return owed - the amount of $WOOL earned
   */
  function _claimWolfFromPack(uint256 tokenId, bool unstake) internal returns (uint256 owed) {
    require(woolf.ownerOf(tokenId) == address(this), "AINT A PART OF THE PACK");
    uint256 alpha = _alphaForWolf(tokenId);
    Stake memory stake = pack[alpha][packIndices[tokenId]];
    require(stake.owner == _msgSender(), "SWIPER, NO SWIPING");
    owed = (alpha) * (woolPerAlpha - stake.value); // Calculate portion of tokens based on Alpha
    if (unstake) {
      totalAlphaStaked -= alpha; // Remove Alpha from total staked
      woolf.safeTransferFrom(address(this), _msgSender(), tokenId, ""); // Send back Wolf
      Stake memory lastStake = pack[alpha][pack[alpha].length - 1];
      pack[alpha][packIndices[tokenId]] = lastStake; // Shuffle last Wolf to current position
      packIndices[lastStake.tokenId] = packIndices[tokenId];
      pack[alpha].pop(); // Remove duplicate
      delete packIndices[tokenId]; // Delete old mapping
    } else {
      pack[alpha][packIndices[tokenId]] = Stake({
        owner: _msgSender(),
        tokenId: uint16(tokenId),
        value: uint80(woolPerAlpha)
      }); // reset stake
    }
    emit WolfClaimed(tokenId, owed, unstake);
  }

  /**
   * emergency unstake tokens
   * @param tokenIds the IDs of the tokens to claim earnings from
   */
  function rescue(uint256[] calldata tokenIds) external {
    require(rescueEnabled, "RESCUE DISABLED");
    uint256 tokenId;
    Stake memory stake;
    Stake memory lastStake;
    uint256 alpha;
    for (uint i = 0; i < tokenIds.length; i++) {
      tokenId = tokenIds[i];
      if (isSheep(tokenId)) {
        stake = barn[tokenId];
        require(stake.owner == _msgSender(), "SWIPER, NO SWIPING");
        woolf.safeTransferFrom(address(this), _msgSender(), tokenId, ""); // send back Sheep
        delete barn[tokenId];
        totalSheepStaked -= 1;
        emit SheepClaimed(tokenId, 0, true);
      } else {
        alpha = _alphaForWolf(tokenId);
        stake = pack[alpha][packIndices[tokenId]];
        require(stake.owner == _msgSender(), "SWIPER, NO SWIPING");
        totalAlphaStaked -= alpha; // Remove Alpha from total staked
        woolf.safeTransferFrom(address(this), _msgSender(), tokenId, ""); // Send back Wolf
        lastStake = pack[alpha][pack[alpha].length - 1];
        pack[alpha][packIndices[tokenId]] = lastStake; // Shuffle last Wolf to current position
        packIndices[lastStake.tokenId] = packIndices[tokenId];
        pack[alpha].pop(); // Remove duplicate
        delete packIndices[tokenId]; // Delete old mapping
        emit WolfClaimed(tokenId, 0, true);
      }
    }
  }

  /** ACCOUNTING */

  /** 
   * add $WOOL to claimable pot for the Pack
   * @param amount $WOOL to add to the pot
   */
  function _payWolfTax(uint256 amount) internal {
    if (totalAlphaStaked == 0) { // if there's no staked wolves
      unaccountedRewards += amount; // keep track of $WOOL due to wolves
      return;
    }
    // makes sure to include any unaccounted $WOOL 
    woolPerAlpha += (amount + unaccountedRewards) / totalAlphaStaked;
    unaccountedRewards = 0;
  }

  /**
   * tracks $WOOL earnings to ensure it stops once 2.4 billion is eclipsed
   */
  modifier _updateEarnings() {
    if (totalWoolEarned < MAXIMUM_GLOBAL_WOOL) {
      totalWoolEarned += 
        (block.timestamp - lastClaimTimestamp)
        * totalSheepStaked
        * DAILY_WOOL_RATE / 1 days; 
      lastClaimTimestamp = block.timestamp;
    }
    _;
  }

  /** ADMIN */

  /**
   * allows owner to enable "rescue mode"
   * simplifies accounting, prioritizes tokens out in emergency
   */
  function setRescueEnabled(bool _enabled) external onlyOwner {
    rescueEnabled = _enabled;
  }

  /**
   * enables owner to pause / unpause minting
   */
  function setPaused(bool _paused) external onlyOwner {
    if (_paused) _pause();
    else _unpause();
  }

  /** READ ONLY */

  /**
   * checks if a token is a Sheep
   * @param tokenId the ID of the token to check
   * @return sheep - whether or not a token is a Sheep
   */
  function isSheep(uint256 tokenId) public view returns (bool sheep) {
    (sheep, , , , , , , , , ) = woolf.tokenTraits(tokenId);
  }

  /**
   * gets the alpha score for a Wolf
   * @param tokenId the ID of the Wolf to get the alpha score for
   * @return the alpha score of the Wolf (5-8)
   */
  function _alphaForWolf(uint256 tokenId) internal view returns (uint8) {
    ( , , , , , , , , , uint8 alphaIndex) = woolf.tokenTraits(tokenId);
    return MAX_ALPHA - alphaIndex; // alpha index is 0-3
  }

  /**
   * chooses a random Wolf thief when a newly minted token is stolen
   * @param seed a random value to choose a Wolf from
   * @return the owner of the randomly selected Wolf thief
   */
  function randomWolfOwner(uint256 seed) external view returns (address) {
    if (totalAlphaStaked == 0) return address(0x0);
    uint256 bucket = (seed & 0xFFFFFFFF) % totalAlphaStaked; // choose a value from 0 to total alpha staked
    uint256 cumulative;
    seed >>= 32;
    // loop through each bucket of Wolves with the same alpha score
    for (uint i = MAX_ALPHA - 3; i <= MAX_ALPHA; i++) {
      cumulative += pack[i].length * i;
      // if the value is not inside of that bucket, keep going
      if (bucket >= cumulative) continue;
      // get the address of a random Wolf with that alpha score
      return pack[i][seed % pack[i].length].owner;
    }
    return address(0x0);
  }

  /**
   * generates a pseudorandom number
   * @param seed a value ensure different outcomes for different sources in the same block
   * @return a pseudorandom value
   */
  function random(uint256 seed) internal view returns (uint256) {
    return uint256(keccak256(abi.encodePacked(
      tx.origin,
      blockhash(block.number - 1),
      block.timestamp,
      seed
    )));
  }

  function onERC721Received(
        address,
        address from,
        uint256,
        bytes calldata
    ) external pure override returns (bytes4) {
      require(from == address(0x0), "Cannot send tokens to Barn directly");
      return IERC721Receiver.onERC721Received.selector;
    }

  
}
// File: Context.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

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

// File: ContextUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (utils/Context.sol)

pragma solidity ^0.8.0;
import "./Initializable.sol";

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

    function __Context_init_unchained() internal initializer {
    }
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
    uint256[50] private __gap;
}

// File: ERC165.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IERC165.sol";

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

// File: ERC165Upgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (utils/introspection/ERC165.sol)

pragma solidity ^0.8.0;

import "./IERC165Upgradeable.sol";
import "./Initializable.sol";

/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165Upgradeable is Initializable, IERC165Upgradeable {
    function __ERC165_init() internal initializer {
        __ERC165_init_unchained();
    }

    function __ERC165_init_unchained() internal initializer {
    }
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165Upgradeable).interfaceId;
    }
    uint256[50] private __gap;
}

// File: ERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IERC20.sol";
import "./IERC20Metadata.sol";
import "./Context.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20, IERC20Metadata {
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * The default value of {decimals} is 18. To select a different value for
     * {decimals} you should overload it.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless this function is
     * overridden;
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * Requirements:
     *
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for ``sender``'s tokens of at least
     * `amount`.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);

        uint256 currentAllowance = _allowances[sender][_msgSender()];
        require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
        unchecked {
            _approve(sender, _msgSender(), currentAllowance - amount);
        }

        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        uint256 currentAllowance = _allowances[_msgSender()][spender];
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(_msgSender(), spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    /**
     * @dev Moves `amount` of tokens from `sender` to `recipient`.
     *
     * This internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(
        address sender,
        address recipient,
        uint256 amount
    ) internal virtual {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(sender, recipient, amount);

        uint256 senderBalance = _balances[sender];
        require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[sender] = senderBalance - amount;
        }
        _balances[recipient] += amount;

        emit Transfer(sender, recipient, amount);

        _afterTokenTransfer(sender, recipient, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
        }
        _totalSupply -= amount;

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}

// File: ERC721.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

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

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

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

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

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

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

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

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

    /**
     * @dev See {IERC721-balanceOf}.
     */
    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), "ERC721: balance query for the zero address");
        return _balances[owner];
    }

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

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

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

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");

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

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

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

        require(
            _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
            "ERC721: approve caller is not owner nor approved for all"
        );

        _approve(to, tokenId);
    }

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

        return _tokenApprovals[tokenId];
    }

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

        _operatorApprovals[_msgSender()][operator] = approved;
        emit ApprovalForAll(_msgSender(), operator, approved);
    }

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

    /**
     * @dev See {IERC721-transferFrom}.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");

        _transfer(from, to, tokenId);
    }

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

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
        _safeTransfer(from, to, tokenId, _data);
    }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        _beforeTokenTransfer(from, to, tokenId);

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

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

        emit Transfer(from, to, tokenId);
    }

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

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

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, ``from``'s `tokenId` will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {}
}

// File: ERC721Enumerable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./ERC721.sol";
import "./IERC721Enumerable.sol";

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

// File: ERC721Upgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (token/ERC721/ERC721.sol)

pragma solidity ^0.8.0;

import "./IERC721Upgradeable.sol";
import "./IERC721ReceiverUpgradeable.sol";
import "./IERC721MetadataUpgradeable.sol";
import "./AddressUpgradeable.sol";
import "./ContextUpgradeable.sol";
import "./StringsUpgradeable.sol";
import "./ERC165Upgradeable.sol";
import "./Initializable.sol";

/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension, but not including the Enumerable extension, which is available separately as
 * {ERC721Enumerable}.
 */
contract ERC721Upgradeable is Initializable, ContextUpgradeable, ERC165Upgradeable, IERC721Upgradeable, IERC721MetadataUpgradeable {
    using AddressUpgradeable for address;
    using StringsUpgradeable for uint256;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

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

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

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

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

    /**
     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
     */
    function __ERC721_init(string memory name_, string memory symbol_) internal initializer {
        __Context_init_unchained();
        __ERC165_init_unchained();
        __ERC721_init_unchained(name_, symbol_);
    }

    function __ERC721_init_unchained(string memory name_, string memory symbol_) internal initializer {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165Upgradeable, IERC165Upgradeable) returns (bool) {
        return
            interfaceId == type(IERC721Upgradeable).interfaceId ||
            interfaceId == type(IERC721MetadataUpgradeable).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721-balanceOf}.
     */
    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), "ERC721: balance query for the zero address");
        return _balances[owner];
    }

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

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

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

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");

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

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

    /**
     * @dev See {IERC721-approve}.
     */
    function approve(address to, uint256 tokenId) public virtual override {
        address owner = ERC721Upgradeable.ownerOf(tokenId);
        require(to != owner, "ERC721: approval to current owner");

        require(
            _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
            "ERC721: approve caller is not owner nor approved for all"
        );

        _approve(to, tokenId);
    }

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

        return _tokenApprovals[tokenId];
    }

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

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

    /**
     * @dev See {IERC721-transferFrom}.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");

        _transfer(from, to, tokenId);
    }

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

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
        _safeTransfer(from, to, tokenId, _data);
    }

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

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

    /**
     * @dev Returns whether `spender` is allowed to manage `tokenId`.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
        require(_exists(tokenId), "ERC721: operator query for nonexistent token");
        address owner = ERC721Upgradeable.ownerOf(tokenId);
        return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
    }

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

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

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

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

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

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

    /**
     * @dev Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId) internal virtual {
        address owner = ERC721Upgradeable.ownerOf(tokenId);

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

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

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

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

    /**
     * @dev Transfers `tokenId` from `from` to `to`.
     *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     *
     * Emits a {Transfer} event.
     */
    function _transfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {
        require(ERC721Upgradeable.ownerOf(tokenId) == from, "ERC721: transfer of token that is not own");
        require(to != address(0), "ERC721: transfer to the zero address");

        _beforeTokenTransfer(from, to, tokenId);

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

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

        emit Transfer(from, to, tokenId);
    }

    /**
     * @dev Approve `to` to operate on `tokenId`
     *
     * Emits a {Approval} event.
     */
    function _approve(address to, uint256 tokenId) internal virtual {
        _tokenApprovals[tokenId] = to;
        emit Approval(ERC721Upgradeable.ownerOf(tokenId), to, tokenId);
    }

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

    /**
     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
     * The call is not executed if the target address is not a contract.
     *
     * @param from address representing the previous owner of the given token ID
     * @param to target address that will receive the tokens
     * @param tokenId uint256 ID of the token to be transferred
     * @param _data bytes optional data to send along with the call
     * @return bool whether the call correctly returned the expected magic value
     */
    function _checkOnERC721Received(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) private returns (bool) {
        if (to.isContract()) {
            try IERC721ReceiverUpgradeable(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
                return retval == IERC721ReceiverUpgradeable.onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert("ERC721: transfer to non ERC721Receiver implementer");
                } else {
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            return true;
        }
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, ``from``'s `tokenId` will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {}
    uint256[44] private __gap;
}

// File: IBarn.sol



// SPDX-License-Identifier: MIT LICENSE 

pragma solidity ^0.8.0;

interface IBarn {
  function addManyToBarnAndPack(address account, uint16[] calldata tokenIds) external;
  function randomWolfOwner(uint256 seed) external view returns (address);
}
// File: IDateTime.sol



// SPDX-License-Identifier: MIT LICENSE
pragma solidity ^0.8.0;

interface IDateTime {
  function getYear(uint timestamp) external pure returns (uint16);
  function getMonth(uint timestamp) external pure returns (uint16);
  function getDay(uint timestamp) external pure returns (uint16);
  function getHour(uint timestamp) external pure returns (uint16);
  function getMinute(uint timestamp) external pure returns (uint16);
  function getSecond(uint timestamp) external pure returns (uint16);
}
// File: IERC165.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

// File: IERC165Upgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165Upgradeable {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

// File: IERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: IERC20Metadata.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IERC20.sol";

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

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

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

// File: IERC721.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IERC165.sol";

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

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

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

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

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

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

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

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

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

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

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

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

// File: IERC721Enumerable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IERC721.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Enumerable is IERC721 {
    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalSupply() external view returns (uint256);

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

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

// File: IERC721Metadata.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IERC721.sol";

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

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

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

// File: IERC721MetadataUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (token/ERC721/extensions/IERC721Metadata.sol)

pragma solidity ^0.8.0;

import "./IERC721Upgradeable.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721MetadataUpgradeable is IERC721Upgradeable {
    /**
     * @dev Returns the token collection name.
     */
    function name() external view returns (string memory);

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

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

// File: IERC721Receiver.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

// File: IERC721ReceiverUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721ReceiverUpgradeable {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

// File: IERC721Upgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

import "./IERC165Upgradeable.sol";

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721Upgradeable is IERC165Upgradeable {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

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

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

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

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

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

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

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

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

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

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

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

// File: Initializable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (proxy/utils/Initializable.sol)

pragma solidity ^0.8.0;

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 *
 * [CAUTION]
 * ====
 * Avoid leaving a contract uninitialized.
 *
 * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
 * contract, which may impact the proxy. To initialize the implementation contract, you can either invoke the
 * initializer manually, or you can include a constructor to automatically mark it as initialized when it is deployed:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * /// @custom:oz-upgrades-unsafe-allow constructor
 * constructor() initializer {}
 * ```
 * ====
 */
abstract contract Initializable {
    /**
     * @dev Indicates that the contract has been initialized.
     */
    bool private _initialized;

    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;

    /**
     * @dev Modifier to protect an initializer function from being invoked twice.
     */
    modifier initializer() {
        require(_initializing || !_initialized, "Initializable: contract is already initialized");

        bool isTopLevelCall = !_initializing;
        if (isTopLevelCall) {
            _initializing = true;
            _initialized = true;
        }

        _;

        if (isTopLevelCall) {
            _initializing = false;
        }
    }
}

// File: ITraits.sol



// SPDX-License-Identifier: MIT LICENSE 

pragma solidity ^0.8.0;

interface ITraits {
  function tokenURI(uint256 tokenId) external view returns (string memory);
}
// File: IWoolf.sol



// SPDX-License-Identifier: MIT LICENSE

pragma solidity ^0.8.0;

interface IWoolf {

  // struct to store each token's traits
  struct SheepWolf {
    bool isSheep;
    uint8 fur;
    uint8 head;
    uint8 ears;
    uint8 eyes;
    uint8 nose;
    uint8 mouth;
    uint8 neck;
    uint8 feet;
    uint8 alphaIndex;
  }


  function getPaidTokens() external view returns (uint256);
  function getTokenTraits(uint256 tokenId) external view returns (SheepWolf memory);
}
// File: IWoolfMetadata.sol



// SPDX-License-Identifier: MIT LICENSE  

pragma solidity ^0.8.0;

interface IWoolfMetadata {
  function tokenURI(uint256 tokenId) external view returns (string memory);
}
// File: LinkTokenInterface.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface LinkTokenInterface {

  function allowance(
    address owner,
    address spender
  )
    external
    view
    returns (
      uint256 remaining
    );

  function approve(
    address spender,
    uint256 value
  )
    external
    returns (
      bool success
    );

  function balanceOf(
    address owner
  )
    external
    view
    returns (
      uint256 balance
    );

  function decimals()
    external
    view
    returns (
      uint8 decimalPlaces
    );

  function decreaseApproval(
    address spender,
    uint256 addedValue
  )
    external
    returns (
      bool success
    );

  function increaseApproval(
    address spender,
    uint256 subtractedValue
  ) external;

  function name()
    external
    view
    returns (
      string memory tokenName
    );

  function symbol()
    external
    view
    returns (
      string memory tokenSymbol
    );

  function totalSupply()
    external
    view
    returns (
      uint256 totalTokensIssued
    );

  function transfer(
    address to,
    uint256 value
  )
    external
    returns (
      bool success
    );

  function transferAndCall(
    address to,
    uint256 value,
    bytes calldata data
  )
    external
    returns (
      bool success
    );

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

}

// File: Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./Context.sol";

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

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

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

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

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

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

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

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: OwnableUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (access/Ownable.sol)

pragma solidity ^0.8.0;

import "./ContextUpgradeable.sol";
import "./Initializable.sol";

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

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    function __Ownable_init() internal initializer {
        __Context_init_unchained();
        __Ownable_init_unchained();
    }

    function __Ownable_init_unchained() internal initializer {
        _transferOwnership(_msgSender());
    }

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

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

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

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

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
    uint256[49] private __gap;
}

// File: Pausable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./Context.sol";

/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
abstract contract Pausable is Context {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state.
     */
    constructor() {
        _paused = false;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        require(!paused(), "Pausable: paused");
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        require(paused(), "Pausable: not paused");
        _;
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
}

// File: PausableUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (security/Pausable.sol)

pragma solidity ^0.8.0;

import "./ContextUpgradeable.sol";
import "./Initializable.sol";

/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
abstract contract PausableUpgradeable is Initializable, ContextUpgradeable {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state.
     */
    function __Pausable_init() internal initializer {
        __Context_init_unchained();
        __Pausable_init_unchained();
    }

    function __Pausable_init_unchained() internal initializer {
        _paused = false;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        require(!paused(), "Pausable: paused");
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        require(paused(), "Pausable: not paused");
        _;
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
    uint256[49] private __gap;
}

// File: RiskyGame.sol



// SPDX-License-Identifier: MIT LICENSE 

pragma solidity ^0.8.0;

import "./LinkTokenInterface.sol";
import "./WoolfReborn.sol";
import "./Barn.sol";
import "./WoolPouch.sol";

contract RiskyGame is 
  Initializable, 
  OwnableUpgradeable, 
  PausableUpgradeable
{

  /*

  Security notes
  ==============

  - Ignoring some Slither warnings regarding sanity checks in the initializer.
  - Ignoring Slither warnings about state changes after calls and usage of block timestamp as it's intended behavior.
  - The game logic trades off gas efficiency for precision. Supply will converge to approximately 2.4b tokens when everybody has claimed. If the number of sheep choosing yes risk is uneven and very small, the final amount will somewhat deviate from that number, but in practice the difference should be negligible.

  */

  bool public optInsEnabled;
  // 14000 tokens / 256 bits x 2 bits
  uint256[110] public tokenStates;

  uint128 public safeGameWool;
  uint128 public riskGameWool;
  uint128 constant TOTAL_GEN0_GEN1 = 13809;
  uint128 constant TOTAL_SHEEP = 12066;
  uint8 constant MAX_ALPHA = 8;
  uint128 constant TOTAL_ALPHA = 9901; 
  uint128 constant BARN_PAUSE_TIMESTAMP = 1637559109;
  uint128 constant MIGRATION_TIMESTAMP = 1638072344;
  uint128 public constant UNSTAKED_EARNINGS = (MIGRATION_TIMESTAMP - BARN_PAUSE_TIMESTAMP) * 10000 ether / 1 days; 
  uint128 constant TOTAL_UNSTAKED_EARNINGS = UNSTAKED_EARNINGS * 310; // NUMBER OF SHEEP THAT WERE UNSTAKED
  uint128 constant TOTAL_STAKED_EARNINGS = 786726742013904746845306880; // PULLED DIRECTLY FROM THE BLOCKCHAIN
  uint128 constant TOTAL_CLAIMED_WOOL = 230110840213821712918605852; // PULLED DIRECTLY FROM THE BLOCKCHAIN
  uint128 constant MAXIMUM_WOOL = 2400000000 ether;
  uint128 public totalRiskTakers;

  uint256 constant STATE_UNDECIDED = 0;
  uint256 constant STATE_OPTED_IN = 1;
  uint256 constant STATE_EXECUTED = 2;

  uint256 public randomSeed; // THIS VALUE WILL COME FROM CHAINLINK

  Woolf public woolf;
  WoolfReborn public woolfReborn;
  Barn public barn;
  WoolPouch public woolPouch;

  // Chainlink references
  LinkTokenInterface internal LINK;
  uint256 linkFee;
  address private vrfCoordinator;
  mapping(bytes32 => uint256) private nonces;

  event SafeClaim(
    address recipient,
    uint256[] tokenIds,
    uint256 amount
  );

  event OptForRisk(
    address owner,
    uint256[] tokenIds
  );

  event RiskyClaim(
    address recipient,
    uint256[] tokenIds,
    bool[] winners,
    uint256 amount
  );

  event WolfClaim(
    address recipient,
    uint256[] tokenIds,
    uint256 amount
  );

  /** 
   * initializes contract
   * @param _woolfReborn reference to WoolfReborn
   * @param _woolf reference to Woolf 
   * @param _barn reference to original Barn
   * @param _woolPouch reference to WoolPouch
   * @param _LINK reference to LINK token
   * @param _vrfCoordinator reference to Chainlink VRF coordinator
   */
  function initialize(
    address _woolfReborn, 
    address _woolf, 
    address _barn, 
    address _woolPouch,
    address _LINK,
    address _vrfCoordinator
  ) external initializer {
    __Ownable_init();
    __Pausable_init();

    woolfReborn = WoolfReborn(_woolfReborn);
    woolf = Woolf(_woolf);
    barn = Barn(_barn);
    woolPouch = WoolPouch(_woolPouch);

    LINK = LinkTokenInterface(_LINK);
    vrfCoordinator = _vrfCoordinator;

    riskGameWool = MAXIMUM_WOOL - TOTAL_CLAIMED_WOOL - TOTAL_STAKED_EARNINGS - TOTAL_UNSTAKED_EARNINGS;

    _pause();
    optInsEnabled = true;
    linkFee = 2 ether;
  }

  /** EXTERNAL */

  /**
   * opts into the No Risk option and claims WOOL Pouches
   * @param tokenIds the Sheep to opt in
   * @param separatePouches whether or not to give a single Pouch or one for each Sheep
   */
  function playItSafe(uint256[] calldata tokenIds, bool separatePouches) external whenNotPaused {
    uint128 earned;
    uint128 temp;
    for (uint256 i = 0; i < tokenIds.length; i++) {
      require(woolfReborn.ownerOf(tokenIds[i]) == _msgSender(), "SWIPER NO SWIPING");
      require(tokenIds[i] <= TOTAL_GEN0_GEN1, "ONLY ORIGINALS CAN PLAY RISKY GAME");
      require(_isSheep(tokenIds[i]), "WOLVES CANT PLAY IT SAFE");
      require(getTokenState(tokenIds[i]) == STATE_UNDECIDED, "CANT CLAIM TWICE");
      temp = getWoolDue(tokenIds[i]);
      
      setTokenState(tokenIds[i], STATE_EXECUTED);
      if (separatePouches) {
        woolPouch.mint(_msgSender(), temp * 4 / 5, 365 * 4); // charge 20% tax
      }
      earned += temp;
    }

    safeGameWool += earned;
    if (!separatePouches) {
      woolPouch.mint(_msgSender(), earned * 4 / 5, 365 * 4); // charge 20% tax
    }
    emit SafeClaim(_msgSender(), tokenIds, earned);
  }

  /**
   * opts into the Yes Risk option
   * @param tokenIds the Sheep to opt in
   */
  function takeARisk(uint256[] calldata tokenIds) external whenNotPaused {
    require(optInsEnabled, "OPPORTUNITY TO TAKE RISK HAS PASSED");
    for (uint256 i = 0; i < tokenIds.length; i++) {
      require(woolfReborn.ownerOf(tokenIds[i]) == _msgSender(), "SWIPER NO SWIPING");
      require(tokenIds[i] <= TOTAL_GEN0_GEN1, "ONLY ORIGINALS CAN PLAY RISKY GAME");
      require(_isSheep(tokenIds[i]), "WOLVES CANT TAKE THIS RISK");
      require(getTokenState(tokenIds[i]) == STATE_UNDECIDED, "CANT CLAIM TWICE");

      setTokenState(tokenIds[i], STATE_OPTED_IN);
      riskGameWool += getWoolDue(tokenIds[i]);
      totalRiskTakers += 1;
    }
    emit OptForRisk(_msgSender(), tokenIds);
  }

  /**
   * reveals the results of Yes Risk for Sheep and gives WOOL Pouches
   * @param tokenIds the Wolves to claim WOOL Pouches for
   * @param separatePouches whether or not to give a single Pouch or one for each Sheep
   */
  function executeRisk(uint256[] calldata tokenIds, bool separatePouches) external whenNotPaused {
    require(randomSeed != 0x0, "CANT EXECUTE YET");
    bool[] memory winners = new bool[](tokenIds.length);
    uint128 earned;
    for (uint256 i = 0; i < tokenIds.length; i++) {
      require(woolfReborn.ownerOf(tokenIds[i]) == _msgSender(), "SWIPER NO SWIPING");
      require(tokenIds[i] <= TOTAL_GEN0_GEN1, "ONLY ORIGINALS CAN PLAY RISKY GAME");
      require(_isSheep(tokenIds[i]), "WOLVES CANT TAKE THIS RISK");
      require(getTokenState(tokenIds[i]) == STATE_OPTED_IN, "YOU DIDNT OPT FOR THE RISK");
      setTokenState(tokenIds[i], STATE_EXECUTED);
      if (!didSheepDefeatWolves(tokenIds[i])) continue;
      
      if (separatePouches) {
        woolPouch.mint(_msgSender(), riskGameWool / totalRiskTakers, 365 * 4);
      }
      earned += riskGameWool / totalRiskTakers;
      winners[i] = true;
    }

    if (!separatePouches && earned > 0) {
      woolPouch.mint(_msgSender(), earned, 365 * 4);
    }
    emit RiskyClaim(_msgSender(), tokenIds, winners, earned);
  }

  /**
   * claims the taxed and Yes Risk earnings for wolves in WOOL Pouches
   * @param tokenIds the Wolves to claim WOOL Pouches for
   * @param separatePouches whether or not to give a single Pouch or one for each Wolf
   */
  function claimWolfEarnings(uint256[] calldata tokenIds, bool separatePouches) external whenNotPaused {
    require(randomSeed != 0x0, "CANT EXECUTE YET");
    uint128 earned;
    uint128 alpha;
    uint128 temp;
    // amount in taxes is 20% of remainder after unclaimed wool from v1 and risk game
    uint128 taxes = (MAXIMUM_WOOL - riskGameWool - TOTAL_CLAIMED_WOOL) / 5;
    // if there are no sheep playing risk game, wolves win the whole pot
    uint128 totalWolfEarnings = taxes + riskGameWool / (totalRiskTakers > 0 ? 2 : 1); 
    for (uint256 i = 0; i < tokenIds.length; i++) {
      require(woolfReborn.ownerOf(tokenIds[i]) == _msgSender(), "SWIPER NO SWIPING");
      require(tokenIds[i] <= TOTAL_GEN0_GEN1, "ONLY ORIGINALS CAN PLAY RISKY GAME");
      require(!_isSheep(tokenIds[i]), "SHEEP DONT STEAL");
      require(getTokenState(tokenIds[i]) == STATE_UNDECIDED, "CANT CLAIM TWICE");
      setTokenState(tokenIds[i], STATE_EXECUTED);
      alpha = _alphaForWolf(tokenIds[i]);
      temp = totalWolfEarnings * alpha / TOTAL_ALPHA;
      earned += temp;
      if (separatePouches) {
        woolPouch.mint(_msgSender(), temp, 365 * 4);
      }
    } 
    if (!separatePouches && earned > 0) {
      woolPouch.mint(_msgSender(), earned, 365 * 4);
    }
    emit WolfClaim(_msgSender(), tokenIds, earned);
  }

  /**
   * gets the WOOL due for a Sheep based on their state before Barn v1 was paused
   * @param tokenId the Sheep to check the WOOL due for
   */
  function getWoolDue(uint256 tokenId) internal view returns (uint128) {
    if (woolf.ownerOf(tokenId) == address(barn)) {
      // Sheep that were staked earn all their earnings up until the migration
      ( , uint80 value, ) = barn.barn(tokenId);
      return (MIGRATION_TIMESTAMP - value) * 10000 ether / 1 days; 
    } else {
      // Sheep that were not staked receive what they would have earned between the pause and migration
      return UNSTAKED_EARNINGS;
    }
  }

  function didSheepDefeatWolves(uint256 tokenId) public view returns (bool) {
    return uint256(keccak256(abi.encodePacked(tokenId, randomSeed))) & 1 == 1; // 50/50
  }

  function _isSheep(uint256 tokenId) public view returns (bool sheep) {
    (sheep, , , , , , , , , ) = woolf.tokenTraits(tokenId);
  }

  function _alphaForWolf(uint256 tokenId) internal view returns (uint8) {
    ( , , , , , , , , , uint8 alphaIndex) = woolf.tokenTraits(tokenId);
    return MAX_ALPHA - alphaIndex; // alpha index is 0-3
  }

  /**
   * gets the token's state from a 256 bit integer
   */
  function getTokenState(uint256 tokenId) public view returns (uint256 selection) {
    uint256 packed = tokenStates[tokenId / 128];
    return (packed >> ((tokenId % 128) * 2)) & 0x3;
  }

  /**
   * packs the token's state into a 256 bit integer to save gas
   */
  function setTokenState(uint256 tokenId, uint256 state) internal {
    uint256 packed = tokenStates[tokenId / 128];
    uint256 position = (tokenId % 128) * 2;
    tokenStates[tokenId / 128] = ((packed & ~(0x3 << position)) | (state << position));
  }

  /** ADMIN */

  /**
   * begins risky game by getting a random number from Chainlink
   */
  function initiateRiskGame() external onlyOwner {
    optInsEnabled = false;
    requestRandomness(
      0xAA77729D3466CA35AE8D28B3BBAC7CC36A5031EFDC430821C02BC31A238AF445, 
      linkFee
    );
  }

  /**
   * enables owner to pause / unpause minting
   */
  function setPaused(bool _paused) external onlyOwner {
    if (_paused) _pause();
    else _unpause();
  }

  function updateLinkFee(uint256 fee) external onlyOwner {
    linkFee = fee;
  }

  /** CHAINLINK */
  
  // made compatible with upgradeability from here: 
  // https://github.com/smartcontractkit/chainlink/blob/develop/contracts/src/v0.8/VRFConsumerBase.sol

  function requestRandomness(bytes32 _keyHash, uint256 _fee) internal returns (bytes32 requestId) {
    LINK.transferAndCall(vrfCoordinator, _fee, abi.encode(_keyHash, 0));
    uint256 vRFSeed = makeVRFInputSeed(_keyHash, 0, address(this), nonces[_keyHash]); //USER_SEED
    nonces[_keyHash] = nonces[_keyHash] + 1;
    return makeRequestId(_keyHash, vRFSeed);
  }

  function rawFulfillRandomness(bytes32, uint256 randomness) external {
    require(_msgSender() == vrfCoordinator, "Only VRFCoordinator can fulfill");
    require(randomSeed == 0x0, "Randomness already set");
    randomSeed = randomness;
  }

  function makeVRFInputSeed(
    bytes32 _keyHash,
    uint256 _userSeed,
    address _requester,
    uint256 _nonce
  ) internal pure returns (uint256) {
    return uint256(keccak256(abi.encode(_keyHash, _userSeed, _requester, _nonce)));
  }

  function makeRequestId(bytes32 _keyHash, uint256 _vRFInputSeed) internal pure returns (bytes32) {
    return keccak256(abi.encodePacked(_keyHash, _vRFInputSeed));
  }
}
// File: Strings.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

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

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

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

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

// File: StringsUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (utils/Strings.sol)

pragma solidity ^0.8.0;

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

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

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

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

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

// File: Traits.sol



// SPDX-License-Identifier: MIT LICENSE

pragma solidity ^0.8.0;
import "./Ownable.sol";
import "./Strings.sol";
import "./ITraits.sol";
import "./IWoolf.sol";

contract Traits is Ownable, ITraits {

  using Strings for uint256;

  // struct to store each trait's data for metadata and rendering
  struct Trait {
    string name;
    string png;
  }

  // mapping from trait type (index) to its name
  string[9] _traitTypes = [
    "Fur",
    "Head",
    "Ears",
    "Eyes",
    "Nose",
    "Mouth",
    "Neck",
    "Feet",
    "Alpha"
  ];
  // storage of each traits name and base64 PNG data
  mapping(uint8 => mapping(uint8 => Trait)) public traitData;
  // mapping from alphaIndex to its score
  string[4] _alphas = [
    "8",
    "7",
    "6",
    "5"
  ];

  IWoolf public woolf;

  constructor() {}

  /** ADMIN */

  function setWoolf(address _woolf) external onlyOwner {
    woolf = IWoolf(_woolf);
  }

  /**
   * administrative to upload the names and images associated with each trait
   * @param traitType the trait type to upload the traits for (see traitTypes for a mapping)
   * @param traits the names and base64 encoded PNGs for each trait
   */
  function uploadTraits(uint8 traitType, uint8[] calldata traitIds, Trait[] calldata traits) external onlyOwner {
    require(traitIds.length == traits.length, "Mismatched inputs");
    for (uint i = 0; i < traits.length; i++) {
      traitData[traitType][traitIds[i]] = Trait(
        traits[i].name,
        traits[i].png
      );
    }
  }

  /** RENDER */

  /**
   * generates an <image> element using base64 encoded PNGs
   * @param trait the trait storing the PNG data
   * @return the <image> element
   */
  function drawTrait(Trait memory trait) internal pure returns (string memory) {
    return string(abi.encodePacked(
      '<image x="4" y="4" width="32" height="32" image-rendering="pixelated" preserveAspectRatio="xMidYMid" xlink:href="data:image/png;base64,',
      trait.png,
      '"/>'
    ));
  }

  /**
   * generates an entire SVG by composing multiple <image> elements of PNGs
   * @param tokenId the ID of the token to generate an SVG for
   * @return a valid SVG of the Sheep / Wolf
   */
  function drawSVG(uint256 tokenId) public view returns (string memory) {
    IWoolf.SheepWolf memory s = woolf.getTokenTraits(tokenId);
    uint8 shift = s.isSheep ? 0 : 9;

    string memory svgString = string(abi.encodePacked(
      drawTrait(traitData[0 + shift][s.fur]),
      s.isSheep ? drawTrait(traitData[1 + shift][s.head]) : drawTrait(traitData[1 + shift][s.alphaIndex]),
      s.isSheep ? drawTrait(traitData[2 + shift][s.ears]) : '',
      drawTrait(traitData[3 + shift][s.eyes]),
      s.isSheep ? drawTrait(traitData[4 + shift][s.nose]) : '',
      drawTrait(traitData[5 + shift][s.mouth]),
      s.isSheep ? '' : drawTrait(traitData[6 + shift][s.neck]),
      s.isSheep ? drawTrait(traitData[7 + shift][s.feet]) : ''
    ));

    return string(abi.encodePacked(
      '<svg 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">',
      svgString,
      "</svg>"
    ));
  }

  /**
   * generates an attribute for the attributes array in the ERC721 metadata standard
   * @param traitType the trait type to reference as the metadata key
   * @param value the token's trait associated with the key
   * @return a JSON dictionary for the single attribute
   */
  function attributeForTypeAndValue(string memory traitType, string memory value) internal pure returns (string memory) {
    return string(abi.encodePacked(
      '{"trait_type":"',
      traitType,
      '","value":"',
      value,
      '"}'
    ));
  }

  /**
   * generates an array composed of all the individual traits and values
   * @param tokenId the ID of the token to compose the metadata for
   * @return a JSON array of all of the attributes for given token ID
   */
  function compileAttributes(uint256 tokenId) public view returns (string memory) {
    IWoolf.SheepWolf memory s = woolf.getTokenTraits(tokenId);
    string memory traits;
    if (s.isSheep) {
      traits = string(abi.encodePacked(
        attributeForTypeAndValue(_traitTypes[0], traitData[0][s.fur].name),',',
        attributeForTypeAndValue(_traitTypes[1], traitData[1][s.head].name),',',
        attributeForTypeAndValue(_traitTypes[2], traitData[2][s.ears].name),',',
        attributeForTypeAndValue(_traitTypes[3], traitData[3][s.eyes].name),',',
        attributeForTypeAndValue(_traitTypes[4], traitData[4][s.nose].name),',',
        attributeForTypeAndValue(_traitTypes[5], traitData[5][s.mouth].name),',',
        attributeForTypeAndValue(_traitTypes[7], traitData[7][s.feet].name),','
      ));
    } else {
      traits = string(abi.encodePacked(
        attributeForTypeAndValue(_traitTypes[0], traitData[9][s.fur].name),',',
        attributeForTypeAndValue(_traitTypes[1], traitData[10][s.alphaIndex].name),',',
        attributeForTypeAndValue(_traitTypes[3], traitData[12][s.eyes].name),',',
        attributeForTypeAndValue(_traitTypes[5], traitData[14][s.mouth].name),',',
        attributeForTypeAndValue(_traitTypes[6], traitData[15][s.neck].name),',',
        attributeForTypeAndValue("Alpha Score", _alphas[s.alphaIndex]),','
      ));
    }
    return string(abi.encodePacked(
      '[',
      traits,
      '{"trait_type":"Generation","value":',
      tokenId <= woolf.getPaidTokens() ? '"Gen 0"' : '"Gen 1"',
      '},{"trait_type":"Type","value":',
      s.isSheep ? '"Sheep"' : '"Wolf"',
      '}]'
    ));
  }

  /**
   * generates a base64 encoded metadata response without referencing off-chain content
   * @param tokenId the ID of the token to generate the metadata for
   * @return a base64 encoded JSON dictionary of the token's metadata and SVG
   */
  function tokenURI(uint256 tokenId) public view override returns (string memory) {
    IWoolf.SheepWolf memory s = woolf.getTokenTraits(tokenId);

    string memory metadata = string(abi.encodePacked(
      '{"name": "',
      s.isSheep ? 'Sheep #' : 'Wolf #',
      tokenId.toString(),
      '", "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,',
      base64(bytes(drawSVG(tokenId))),
      '", "attributes":',
      compileAttributes(tokenId),
      "}"
    ));

    return string(abi.encodePacked(
      "data:application/json;base64,",
      base64(bytes(metadata))
    ));
  }

  /** BASE 64 - Written by Brech Devos */
  
  string internal constant TABLE = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';

  function base64(bytes memory data) internal pure returns (string memory) {
    if (data.length == 0) return '';
    
    // load the table into memory
    string memory table = TABLE;

    // multiply by 4/3 rounded up
    uint256 encodedLen = 4 * ((data.length + 2) / 3);

    // add some extra buffer at the end required for the writing
    string memory result = new string(encodedLen + 32);

    assembly {
      // set the actual output length
      mstore(result, encodedLen)
      
      // prepare the lookup table
      let tablePtr := add(table, 1)
      
      // input ptr
      let dataPtr := data
      let endPtr := add(dataPtr, mload(data))
      
      // result ptr, jump over length
      let resultPtr := add(result, 32)
      
      // run over the input, 3 bytes at a time
      for {} lt(dataPtr, endPtr) {}
      {
          dataPtr := add(dataPtr, 3)
          
          // read 3 bytes
          let input := mload(dataPtr)
          
          // write 4 characters
          mstore(resultPtr, shl(248, mload(add(tablePtr, and(shr(18, input), 0x3F)))))
          resultPtr := add(resultPtr, 1)
          mstore(resultPtr, shl(248, mload(add(tablePtr, and(shr(12, input), 0x3F)))))
          resultPtr := add(resultPtr, 1)
          mstore(resultPtr, shl(248, mload(add(tablePtr, and(shr( 6, input), 0x3F)))))
          resultPtr := add(resultPtr, 1)
          mstore(resultPtr, shl(248, mload(add(tablePtr, and(        input,  0x3F)))))
          resultPtr := add(resultPtr, 1)
      }
      
      // padding with '='
      switch mod(mload(data), 3)
      case 1 { mstore(sub(resultPtr, 2), shl(240, 0x3d3d)) }
      case 2 { mstore(sub(resultPtr, 1), shl(248, 0x3d)) }
    }
    
    return result;
  }
}
// File: WOOL.sol



// SPDX-License-Identifier: MIT LICENSE

pragma solidity ^0.8.0;
import "./ERC20.sol";
import "./Ownable.sol";

contract WOOL is ERC20, Ownable {

  // a mapping from an address to whether or not it can mint / burn
  mapping(address => bool) controllers;
  
  constructor() ERC20("WOOL", "WOOL") { }

  /**
   * mints $WOOL to a recipient
   * @param to the recipient of the $WOOL
   * @param amount the amount of $WOOL to mint
   */
  function mint(address to, uint256 amount) external {
    require(controllers[msg.sender], "Only controllers can mint");
    _mint(to, amount);
  }

  /**
   * burns $WOOL from a holder
   * @param from the holder of the $WOOL
   * @param amount the amount of $WOOL to burn
   */
  function burn(address from, uint256 amount) external {
    require(controllers[msg.sender], "Only controllers can burn");
    _burn(from, amount);
  }

  /**
   * enables an address to mint / burn
   * @param controller the address to enable
   */
  function addController(address controller) external onlyOwner {
    controllers[controller] = true;
  }

  /**
   * disables an address from minting / burning
   * @param controller the address to disbale
   */
  function removeController(address controller) external onlyOwner {
    controllers[controller] = false;
  }
}
// File: Woolf.sol



// SPDX-License-Identifier: MIT LICENSE

pragma solidity ^0.8.0;
import "./Ownable.sol";
import "./Pausable.sol";
import "./ERC721Enumerable.sol";
import "./IWoolf.sol";
import "./IBarn.sol";
import "./ITraits.sol";
import "./WOOL.sol";


contract Woolf is IWoolf, ERC721Enumerable, Ownable, Pausable {

  // mint price
  uint256 public constant MINT_PRICE = .069420 ether;
  // max number of tokens that can be minted - 50000 in production
  uint256 public immutable MAX_TOKENS;
  // number of tokens that can be claimed for free - 20% of MAX_TOKENS
  uint256 public PAID_TOKENS;
  // number of tokens have been minted so far
  uint16 public minted;

  // mapping from tokenId to a struct containing the token's traits
  mapping(uint256 => SheepWolf) public tokenTraits;
  // mapping from hashed(tokenTrait) to the tokenId it's associated with
  // used to ensure there are no duplicates
  mapping(uint256 => uint256) public existingCombinations;

  // list of probabilities for each trait type
  // 0 - 9 are associated with Sheep, 10 - 18 are associated with Wolves
  uint8[][18] public rarities;
  // list of aliases for Walker's Alias algorithm
  // 0 - 9 are associated with Sheep, 10 - 18 are associated with Wolves
  uint8[][18] public aliases;

  // reference to the Barn for choosing random Wolf thieves
  IBarn public barn;
  // reference to $WOOL for burning on mint
  WOOL public wool;
  // reference to Traits
  ITraits public traits;

  /** 
   * instantiates contract and rarity tables
   */
  constructor(address _wool, address _traits, uint256 _maxTokens) ERC721("Wolf Game", 'WGAME') { 
    wool = WOOL(_wool);
    traits = ITraits(_traits);
    MAX_TOKENS = _maxTokens;
    PAID_TOKENS = _maxTokens / 5;

    // I know this looks weird but it saves users gas by making lookup O(1)
    // A.J. Walker's Alias Algorithm
    // sheep
    // fur
    rarities[0] = [15, 50, 200, 250, 255];
    aliases[0] = [4, 4, 4, 4, 4];
    // head
    rarities[1] = [190, 215, 240, 100, 110, 135, 160, 185, 80, 210, 235, 240, 80, 80, 100, 100, 100, 245, 250, 255];
    aliases[1] = [1, 2, 4, 0, 5, 6, 7, 9, 0, 10, 11, 17, 0, 0, 0, 0, 4, 18, 19, 19];
    // ears
    rarities[2] =  [255, 30, 60, 60, 150, 156];
    aliases[2] = [0, 0, 0, 0, 0, 0];
    // eyes
    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];
    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];
    // nose
    rarities[4] = [175, 100, 40, 250, 115, 100, 185, 175, 180, 255];
    aliases[4] = [3, 0, 4, 6, 6, 7, 8, 8, 9, 9];
    // mouth
    rarities[5] = [80, 225, 227, 228, 112, 240, 64, 160, 167, 217, 171, 64, 240, 126, 80, 255];
    aliases[5] = [1, 2, 3, 8, 2, 8, 8, 9, 9, 10, 13, 10, 13, 15, 13, 15];
    // neck
    rarities[6] = [255];
    aliases[6] = [0];
    // feet
    rarities[7] = [243, 189, 133, 133, 57, 95, 152, 135, 133, 57, 222, 168, 57, 57, 38, 114, 114, 114, 255];
    aliases[7] = [1, 7, 0, 0, 0, 0, 0, 10, 0, 0, 11, 18, 0, 0, 0, 1, 7, 11, 18];
    // alphaIndex
    rarities[8] = [255];
    aliases[8] = [0];

    // wolves
    // fur
    rarities[9] = [210, 90, 9, 9, 9, 150, 9, 255, 9];
    aliases[9] = [5, 0, 0, 5, 5, 7, 5, 7, 5];
    // head
    rarities[10] = [255];
    aliases[10] = [0];
    // ears
    rarities[11] = [255];
    aliases[11] = [0];
    // eyes
    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];
    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];
    // nose
    rarities[13] = [255];
    aliases[13] = [0];
    // mouth
    rarities[14] = [239, 244, 249, 234, 234, 234, 234, 234, 234, 234, 130, 255, 247];
    aliases[14] = [1, 2, 11, 0, 11, 11, 11, 11, 11, 11, 11, 11, 11];
    // neck
    rarities[15] = [75, 180, 165, 120, 60, 150, 105, 195, 45, 225, 75, 45, 195, 120, 255];
    aliases[15] = [1, 9, 0, 0, 0, 0, 0, 0, 0, 12, 0, 0, 14, 12, 14];
    // feet 
    rarities[16] = [255];
    aliases[16] = [0];
    // alphaIndex
    rarities[17] = [8, 160, 73, 255]; 
    aliases[17] = [2, 3, 3, 3];
  }

  /** EXTERNAL */

  /** 
   * mint a token - 90% Sheep, 10% Wolves
   * The first 20% are free to claim, the remaining cost $WOOL
   */
  function mint(uint256 amount, bool stake) external payable whenNotPaused {
    require(tx.origin == _msgSender(), "Only EOA");
    require(minted + amount <= MAX_TOKENS, "All tokens minted");
    require(amount > 0 && amount <= 10, "Invalid mint amount");
    if (minted < PAID_TOKENS) {
      require(minted + amount <= PAID_TOKENS, "All tokens on-sale already sold");
      require(amount * MINT_PRICE == msg.value, "Invalid payment amount");
    } else {
      require(msg.value == 0);
    }

    uint256 totalWoolCost = 0;
    uint16[] memory tokenIds = stake ? new uint16[](amount) : new uint16[](0);
    uint256 seed;
    for (uint i = 0; i < amount; i++) {
      minted++;
      seed = random(minted);
      generate(minted, seed);
      address recipient = selectRecipient(seed);
      if (!stake || recipient != _msgSender()) {
        _safeMint(recipient, minted);
      } else {
        _safeMint(address(barn), minted);
        tokenIds[i] = minted;
      }
      totalWoolCost += mintCost(minted);
    }
    
    if (totalWoolCost > 0) wool.burn(_msgSender(), totalWoolCost);
    if (stake) barn.addManyToBarnAndPack(_msgSender(), tokenIds);
  }

  /** 
   * the first 20% are paid in ETH
   * the next 20% are 20000 $WOOL
   * the next 40% are 40000 $WOOL
   * the final 20% are 80000 $WOOL
   * @param tokenId the ID to check the cost of to mint
   * @return the cost of the given token ID
   */
  function mintCost(uint256 tokenId) public view returns (uint256) {
    if (tokenId <= PAID_TOKENS) return 0;
    if (tokenId <= MAX_TOKENS * 2 / 5) return 20000 ether;
    if (tokenId <= MAX_TOKENS * 4 / 5) return 40000 ether;
    return 80000 ether;
  }

  function transferFrom(
    address from,
    address to,
    uint256 tokenId
  ) public virtual override {
    // Hardcode the Barn's approval so that users don't have to waste gas approving
    if (_msgSender() != address(barn))
      require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
    _transfer(from, to, tokenId);
  }

  /** INTERNAL */

  /**
   * generates traits for a specific token, checking to make sure it's unique
   * @param tokenId the id of the token to generate traits for
   * @param seed a pseudorandom 256 bit number to derive traits from
   * @return t - a struct of traits for the given token ID
   */
  function generate(uint256 tokenId, uint256 seed) internal returns (SheepWolf memory t) {
    t = selectTraits(seed);
    if (existingCombinations[structToHash(t)] == 0) {
      tokenTraits[tokenId] = t;
      existingCombinations[structToHash(t)] = tokenId;
      return t;
    }
    return generate(tokenId, random(seed));
  }

  /**
   * uses A.J. Walker's Alias algorithm for O(1) rarity table lookup
   * ensuring O(1) instead of O(n) reduces mint cost by more than 50%
   * probability & alias tables are generated off-chain beforehand
   * @param seed portion of the 256 bit seed to remove trait correlation
   * @param traitType the trait type to select a trait for 
   * @return the ID of the randomly selected trait
   */
  function selectTrait(uint16 seed, uint8 traitType) internal view returns (uint8) {
    uint8 trait = uint8(seed) % uint8(rarities[traitType].length);
    if (seed >> 8 < rarities[traitType][trait]) return trait;
    return aliases[traitType][trait];
  }

  /**
   * the first 20% (ETH purchases) go to the minter
   * the remaining 80% have a 10% chance to be given to a random staked wolf
   * @param seed a random value to select a recipient from
   * @return the address of the recipient (either the minter or the Wolf thief's owner)
   */
  function selectRecipient(uint256 seed) internal view returns (address) {
    if (minted <= PAID_TOKENS || ((seed >> 245) % 10) != 0) return _msgSender(); // top 10 bits haven't been used
    address thief = barn.randomWolfOwner(seed >> 144); // 144 bits reserved for trait selection
    if (thief == address(0x0)) return _msgSender();
    return thief;
  }

  /**
   * selects the species and all of its traits based on the seed value
   * @param seed a pseudorandom 256 bit number to derive traits from
   * @return t -  a struct of randomly selected traits
   */
  function selectTraits(uint256 seed) internal view returns (SheepWolf memory t) {    
    t.isSheep = (seed & 0xFFFF) % 10 != 0;
    uint8 shift = t.isSheep ? 0 : 9;
    seed >>= 16;
    t.fur = selectTrait(uint16(seed & 0xFFFF), 0 + shift);
    seed >>= 16;
    t.head = selectTrait(uint16(seed & 0xFFFF), 1 + shift);
    seed >>= 16;
    t.ears = selectTrait(uint16(seed & 0xFFFF), 2 + shift);
    seed >>= 16;
    t.eyes = selectTrait(uint16(seed & 0xFFFF), 3 + shift);
    seed >>= 16;
    t.nose = selectTrait(uint16(seed & 0xFFFF), 4 + shift);
    seed >>= 16;
    t.mouth = selectTrait(uint16(seed & 0xFFFF), 5 + shift);
    seed >>= 16;
    t.neck = selectTrait(uint16(seed & 0xFFFF), 6 + shift);
    seed >>= 16;
    t.feet = selectTrait(uint16(seed & 0xFFFF), 7 + shift);
    seed >>= 16;
    t.alphaIndex = selectTrait(uint16(seed & 0xFFFF), 8 + shift);
  }

  /**
   * converts a struct to a 256 bit hash to check for uniqueness
   * @param s the struct to pack into a hash
   * @return the 256 bit hash of the struct
   */
  function structToHash(SheepWolf memory s) internal pure returns (uint256) {
    return uint256(bytes32(
      abi.encodePacked(
        s.isSheep,
        s.fur,
        s.head,
        s.eyes,
        s.mouth,
        s.neck,
        s.ears,
        s.feet,
        s.alphaIndex
      )
    ));
  }

  /**
   * generates a pseudorandom number
   * @param seed a value ensure different outcomes for different sources in the same block
   * @return a pseudorandom value
   */
  function random(uint256 seed) internal view returns (uint256) {
    return uint256(keccak256(abi.encodePacked(
      tx.origin,
      blockhash(block.number - 1),
      block.timestamp,
      seed
    )));
  }

  /** READ */

  function getTokenTraits(uint256 tokenId) external view override returns (SheepWolf memory) {
    return tokenTraits[tokenId];
  }

  function getPaidTokens() external view override returns (uint256) {
    return PAID_TOKENS;
  }

  /** ADMIN */

  /**
   * called after deployment so that the contract can get random wolf thieves
   * @param _barn the address of the Barn
   */
  function setBarn(address _barn) external onlyOwner {
    barn = IBarn(_barn);
  }

  /**
   * allows owner to withdraw funds from minting
   */
  function withdraw() external onlyOwner {
    payable(owner()).transfer(address(this).balance);
  }

  /**
   * updates the number of tokens for sale
   */
  function setPaidTokens(uint256 _paidTokens) external onlyOwner {
    PAID_TOKENS = _paidTokens;
  }

  /**
   * enables owner to pause / unpause minting
   */
  function setPaused(bool _paused) external onlyOwner {
    if (_paused) _pause();
    else _unpause();
  }

  /** RENDER */

  function tokenURI(uint256 tokenId) public view override returns (string memory) {
    require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
    return traits.tokenURI(tokenId);
  }
}
// File: WoolfReborn.sol



// SPDX-License-Identifier: MIT LICENSE  

pragma solidity ^0.8.0;
import "./Initializable.sol";
import "./OwnableUpgradeable.sol";
import "./PausableUpgradeable.sol";
import "./ERC721Upgradeable.sol";
import "./Barn.sol";
import "./IWoolfMetadata.sol";

contract WoolfReborn is 
  Initializable, 
  ERC721Upgradeable, 
  OwnableUpgradeable, 
  PausableUpgradeable
{

  /*

  Security notes
  ==============

  - Ignoring Slither reentrancy warning in migrate() because called contract is trusted & call / state change order is intended
  - No need for safeTransferFrom here, using transferFrom so we don't have to worry about callbacks
  - We don't do explicit prevent attempts of multiple claims of the same tokenID. _mint will fail if the tokenID already exists
  - Currently there is no ability to burn a token in the contract. If we do introduce burning, we must update the migrate function to not allow a repeat migration of a burned token

  */

  mapping(address => bool) public controllers;

  uint256 constant public ORIGINAL_SUPPLY = 13809;
  uint256 public minted;

  Woolf public woolf;
  Barn public barn;
  IWoolfMetadata public originalMetadata;
  IWoolfMetadata public unoriginalMetadata;

  /** 
   * instantiates contract
   * @param _woolf address of original woolf contract
   * @param _barn address of original barn contract
   */
  function initialize(address _woolf, address _barn) external initializer {
    __Ownable_init();
    __Pausable_init();
    __ERC721_init("Wolf Game", "WGAME");

    woolf = Woolf(_woolf);
    barn = Barn(_barn);
    originalMetadata = IWoolfMetadata(_woolf);

    minted = ORIGINAL_SUPPLY;

    _pause();
  }

  /** EXTERNAL */

  /**
   * creates identical tokens in the new contract
   * and burns any original tokens that are not in the barn
   * @param tokenIds the ids of the tokens to migrate
   */
  function migrate(uint256[] calldata tokenIds) external whenNotPaused {
    for (uint i = 0; i < tokenIds.length; i++) {
      (address owner, bool inBarn) = _ownerOf(tokenIds[i]);
      require(owner == _msgSender(), "STOP! THIEF!");
      if (!inBarn) _attemptBurn(_msgSender(), tokenIds[i]);
      _mint(_msgSender(), tokenIds[i]); // built-in duplicate protection
    }
  }

  /**
   * mints a new ERC721
   * @dev must implement correct checks on controller contract for allowed mints
   * @param recipient address to mint the token to
   */
  function mint(address recipient) external whenNotPaused {
    require(controllers[_msgSender()], "Only controllers can mint");
    _mint(recipient, ++minted);
  }

  /** INTERNAL */

  /**
   * burns a token if its not currently in the barn
   * @param tokenId id of the token to burn
   */
  function _attemptBurn(address owner, uint256 tokenId) internal {
    woolf.transferFrom(owner, address(0xdead), tokenId);
  }

  /**
   * checks if a token is a Sheep
   * @param sheepWolfId the ID of the token to check
   * @return sheep - whether or not a token is a Sheep
   */
  function _isSheep(uint256 sheepWolfId) internal view returns (bool sheep) {
    (sheep, , , , , , , , , ) = woolf.tokenTraits(sheepWolfId);
  }

  /**
   * gets the alpha score for a Wolf
   * @param sheepWolfId the ID of the Wolf to get the alpha score for
   * @return the alpha score of the Wolf (5-8)
   */
  function _alphaForWolf(uint256 sheepWolfId) internal view returns (uint8) {
    ( , , , , , , , , , uint8 alphaIndex) = woolf.tokenTraits(sheepWolfId);
    return 8 - alphaIndex; // alpha index is 0-3
  }

  function _ownerOf(uint256 sheepWolfId) internal view returns (address owner, bool inBarn) {
    owner = woolf.ownerOf(sheepWolfId);
    if (owner != address(barn)) return (owner, false); // if its not in the barn return the owner
    if (_isSheep(sheepWolfId)) {
      ( , , owner) = barn.barn(sheepWolfId);
    } else {
      uint256 index = barn.packIndices(sheepWolfId);
      ( , , owner) = barn.pack(_alphaForWolf(sheepWolfId), index);
    }
    return (owner, true);
  }

  /** ADMIN */

  /**
   * enables owner to pause / unpause minting
   */
  function setPaused(bool _paused) external onlyOwner {
    if (_paused) _pause();
    else _unpause();
  }

  function setOriginalMetadata(address _metadata) external onlyOwner {
    originalMetadata = IWoolfMetadata(_metadata);
  }

  function setUnoriginalMetadata(address _metadata) external onlyOwner {
    unoriginalMetadata = IWoolfMetadata(_metadata);
  }

  /**
   * enables an address to mint / burn
   * @param controller the address to enable
   */
  function addController(address controller) external onlyOwner {
    controllers[controller] = true;
  }

  /**
   * disables an address from minting / burning
   * @param controller the address to disbale
   */
  function removeController(address controller) external onlyOwner {
    controllers[controller] = false;
  }

  /** RENDER */

  function tokenURI(uint256 tokenId) public view override returns (string memory) {
    require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
    if (tokenId <= ORIGINAL_SUPPLY) {
      return originalMetadata.tokenURI(tokenId);
    } else {
      return unoriginalMetadata.tokenURI(tokenId);
    }
  }
}
// File: WoolPouch.sol



// SPDX-License-Identifier: MIT LICENSE 

pragma solidity ^0.8.0;
import "./Initializable.sol";
import "./OwnableUpgradeable.sol";
import "./PausableUpgradeable.sol";
import "./ERC721Upgradeable.sol";
import "./Strings.sol";
import "./WOOL.sol";
import "./IDateTime.sol";

contract WoolPouch is ERC721Upgradeable, OwnableUpgradeable, PausableUpgradeable {
  
  /*

  Security notes
  ==============

  - Claiming can lead to a tiny round down. This can result in negligible, but real losses in dust. This is a tradeoff made to save gas by not requiring storage of already claimed balances.
  - Frontrunning protection: Transfers will revert if WOOL was claimed in the same block.
    We specifically do not show currently claimable balance as part of the metadata to reduce user confusion.
    A longer cooldown on transfers was considered, but ultimately not implemented as it introduces UX issues and additional complexity.
  
  */

  using Strings for uint256;
  using Strings for uint16;

  uint256 constant SECONDS_PER_DAY = 1 days;
  string gif;

  // a mapping from an address to whether or not it can mint / burn
  mapping(address => bool) public controllers;

  uint256 public minted;
  mapping(uint256 => Pouch) public pouches;

  uint256 public constant START_VALUE = 10000 ether;

  struct Pouch {
    bool initialClaimed; // whether or not first 10,000 WOOL has been claimed
    uint16 duration; // stored in days, maxed at 2^16 days
    uint56 lastClaimTimestamp; // stored in seconds, uint56 can store 2 billion years 
    uint56 startTimestamp; // stored in seconds, uint56 can store 2 billion years 
    uint120 amount; // max value, 120 bits is far beyond 5 billion wool supply
  }

  event WoolClaimed(
    address recipient,
    uint256 tokenId,
    uint256 amount
  );

  WOOL public wool;
  IDateTime dateTime;

  function initialize(address _wool, address _dateTime) external initializer {
    __Ownable_init();
    __Pausable_init();
    __ERC721_init("Wool Pouch", "WPOUCH");

    wool = WOOL(_wool);
    dateTime = IDateTime(_dateTime);

    _pause();
  }

  /** EXTERNAL */

  /**
   * claim WOOL tokens from a pouch
   * @param tokenId the token to claim WOOL from
   */
  function claim(uint256 tokenId) external whenNotPaused {
    require(ownerOf(tokenId) == _msgSender(), "SWIPER NO SWIPING");
    uint256 available = amountAvailable(tokenId);
    require(available > 0, "NO MORE EARNINGS AVAILABLE");
    Pouch storage pouch = pouches[tokenId];
    pouch.lastClaimTimestamp = uint56(block.timestamp);
    if (!pouch.initialClaimed) pouch.initialClaimed = true;
    wool.mint(_msgSender(), available);
    emit WoolClaimed(_msgSender(), tokenId, available);
  }

  /**
   * the amount of WOOL currently available to claim in a WOOL pouch
   * @param tokenId the token to check the WOOL for
   */
  function amountAvailable(uint256 tokenId) public view returns (uint256) {
    Pouch memory pouch = pouches[tokenId];
    uint256 currentTimestamp = block.timestamp;
    if (currentTimestamp > uint256(pouch.startTimestamp) + uint256(pouch.duration) * SECONDS_PER_DAY)
      currentTimestamp = uint256(pouch.startTimestamp) + uint256(pouch.duration) * SECONDS_PER_DAY;
    if (pouch.lastClaimTimestamp > currentTimestamp) return 0;
    uint256 elapsed = currentTimestamp - pouch.lastClaimTimestamp;
    return elapsed * uint256(pouch.amount) / (uint256(pouch.duration) * SECONDS_PER_DAY) + 
      (pouch.initialClaimed ? 0 : START_VALUE);
  }

  /** CONTROLLER */

  /**
   * mints $WOOL to a recipient
   * @param to the recipient of the $WOOL
   * @param amount the amount of $WOOL to mint
   */
  function mint(address to, uint128 amount, uint16 duration) external {
    require(controllers[msg.sender], "Only controllers can mint");
    require(amount >= START_VALUE, "Insufficient pouch");
    pouches[++minted] = Pouch({
      initialClaimed: false,
      duration: duration,
      lastClaimTimestamp: uint56(block.timestamp),
      startTimestamp: uint56(block.timestamp),
      amount: uint120(amount - START_VALUE)
    });
    _mint(to, minted);
  }

  /** 
   Override to make sure that transfers can't be frontrun
   */
  function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
        require(pouches[tokenId].lastClaimTimestamp < block.timestamp, "Cannot claim immediately before a transfer");
        _transfer(from, to, tokenId);
    }

  /** 
   Override to make sure that transfers can't be frontrun
   */
  function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) public override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
        require(pouches[tokenId].lastClaimTimestamp < block.timestamp, "Cannot claim immediately before a transfer");
        _safeTransfer(from, to, tokenId, _data);
    }

  /** ADMIN */

  /**
   * enables an address to mint
   * @param controller the address to enable
   */
  function addController(address controller) external onlyOwner {
    controllers[controller] = true;
  }

  /**
   * disables an address from minting
   * @param controller the address to disbale
   */
  function removeController(address controller) external onlyOwner {
    controllers[controller] = false;
  }

  /**
   * enables owner to pause / unpause minting
   */
  function setPaused(bool _paused) external onlyOwner {
    if (_paused) _pause();
    else _unpause();
  }

  /**
   * uploads a gif for the background of the NFT
   * @param _gif the base64 encoded GIF
   */
  function uploadGIF(string calldata _gif) external onlyOwner {
    gif = _gif;
  }

  function generateSVG(uint256 tokenId) internal view returns (string memory) {
    Pouch memory pouch = pouches[tokenId];
    uint256 duration = uint256(pouch.duration) * SECONDS_PER_DAY;
    uint256 endTime = uint256(pouch.startTimestamp) + duration;
    uint256 locked;
    uint256 daysRemaining;
    if (endTime > block.timestamp) {
      locked = (endTime - block.timestamp) * uint256(pouch.amount) / duration;
      daysRemaining = (endTime - block.timestamp) / SECONDS_PER_DAY;
    }
    return string(abi.encodePacked(
      '<svg id="woolpouch" width="100%" height="100%" version="1.1" viewBox="0 0 64 64" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">'
      '<image x="0" y="0" width="64" height="64" image-rendering="pixelated" preserveAspectRatio="xMidYMid" xlink:href="data:image/gif;base64,',gif,
      '"/><text font-family="monospace"><tspan x="13" y="4" font-size="0.25em">Locked WOOL:</tspan><tspan id="g" x="38" y="4" font-size="0.25em">',
      (locked / 1 ether).toString(),
      '</tspan></text><text font-family="monospace"><tspan x="9" y="9" font-size="0.25em">Unlock Period:</tspan><tspan id="b" x="38" y="9" font-size="0.25em">',
      (daysRemaining).toString(),
      ' Days</tspan></text><text font-family="monospace"><tspan x="4" y="13" font-size="0.15em">Before transfer, remember to claim unlocked WOOL</tspan></text>',
      '</svg>'
    ));
  }

  /**
   * generates an attribute for the attributes array in the ERC721 metadata standard
   * @param traitType the trait type to reference as the metadata key
   * @param value the token's trait associated with the key
   * @return a JSON dictionary for the single attribute
   */
  function attributeForTypeAndValue(string memory traitType, string memory value, bool isNumber) internal pure returns (string memory) {
    return string(abi.encodePacked(
      '{"trait_type":"',
      traitType,
      '","value":',
      isNumber ? '' : '"',
      value,
      isNumber ? '' : '"',
      '}'
    ));
  }

  /**
   * sets the attributes of the NFTs, mainly based on current WOOL state
   * @param tokenId the token to get the attributes for
   */
  function compileAttributes(uint256 tokenId) internal view returns (string memory) {
    Pouch memory pouch = pouches[tokenId];
    uint256 duration = uint256(pouch.duration) * SECONDS_PER_DAY;
    uint256 endTime = uint256(pouch.startTimestamp) + duration;
    uint256 locked;
    uint256 daysRemaining;
    if (endTime > block.timestamp) {
      locked = (endTime - block.timestamp) * uint256(pouch.amount) / duration;
      daysRemaining = (endTime - block.timestamp) / SECONDS_PER_DAY;
    }
    string memory attributes = string(abi.encodePacked(
      attributeForTypeAndValue("Locked WOOL", 
        uint256(locked / 1 ether).toString(),
      false),',',
      attributeForTypeAndValue("Time Remaining", 
        string(abi.encodePacked(
          daysRemaining.toString(),
          " Days"
        )),
      false),','
    ));
    attributes = string(abi.encodePacked(
      attributes,
      '{"trait_type":"Last Refreshed","display_type":"date","value":',
      block.timestamp.toString(),
      '},',
      attributeForTypeAndValue("Last Refreshed Time",
        string(abi.encodePacked(
          padNumber(uint256(dateTime.getHour(block.timestamp))),':',
          padNumber(uint256(dateTime.getMinute(block.timestamp))),':',
          padNumber(uint256(dateTime.getSecond(block.timestamp))),' UTC'
        )),
      false),',',
      attributeForTypeAndValue("Last Refreshed Date",
        string(abi.encodePacked(
          padNumber(uint256(dateTime.getMonth(block.timestamp))),'/',
          padNumber(uint256(dateTime.getDay(block.timestamp))),'/',
          uint256(dateTime.getYear(block.timestamp)).toString()
        )),
      false)   
    ));
    return string(abi.encodePacked(
      '[',
      attributes,
      ']'
    ));
  }

  function padNumber(uint256 number) internal pure returns (string memory padded) {
    padded = number.toString();
    return number < 10 ? string(abi.encodePacked('0', padded)) : padded;
  }

  function tokenURI(uint256 tokenId) public view override returns (string memory) {
    require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
    string memory metadata = string(abi.encodePacked(
      '{"name": "WOOL Pouch #',
      tokenId.toString(),
      '","description": "Sellers: before listing, claim any unlocked WOOL in your Pouch on the Wolf Game site.<br /><br />Buyers: When you purchase a WOOL Pouch, assume the previous owner has already claimed its unlocked WOOL. Locked WOOL, which unlocks over time, will be displayed on the image. Refresh the metadata to see the most up to date values.",',
      '"image": "data:image/svg+xml;base64,',
      base64(bytes(generateSVG(tokenId))),
      '", "attributes":',
      compileAttributes(tokenId),
      "}"
    ));

    return string(abi.encodePacked(
      "data:application/json;base64,",
      base64(bytes(metadata))
    ));
  }

  /** BASE 64 - Written by Brech Devos */
  
  string internal constant TABLE = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';

  function base64(bytes memory data) internal pure returns (string memory) {
    if (data.length == 0) return '';
    
    // load the table into memory
    string memory table = TABLE;

    // multiply by 4/3 rounded up
    uint256 encodedLen = 4 * ((data.length + 2) / 3);

    // add some extra buffer at the end required for the writing
    string memory result = new string(encodedLen + 32);

    assembly {
      // set the actual output length
      mstore(result, encodedLen)
      
      // prepare the lookup table
      let tablePtr := add(table, 1)
      
      // input ptr
      let dataPtr := data
      let endPtr := add(dataPtr, mload(data))
      
      // result ptr, jump over length
      let resultPtr := add(result, 32)
      
      // run over the input, 3 bytes at a time
      for {} lt(dataPtr, endPtr) {}
      {
          dataPtr := add(dataPtr, 3)
          
          // read 3 bytes
          let input := mload(dataPtr)
          
          // write 4 characters
          mstore(resultPtr, shl(248, mload(add(tablePtr, and(shr(18, input), 0x3F)))))
          resultPtr := add(resultPtr, 1)
          mstore(resultPtr, shl(248, mload(add(tablePtr, and(shr(12, input), 0x3F)))))
          resultPtr := add(resultPtr, 1)
          mstore(resultPtr, shl(248, mload(add(tablePtr, and(shr( 6, input), 0x3F)))))
          resultPtr := add(resultPtr, 1)
          mstore(resultPtr, shl(248, mload(add(tablePtr, and(        input,  0x3F)))))
          resultPtr := add(resultPtr, 1)
      }
      
      // padding with '='
      switch mod(mload(data), 3)
      case 1 { mstore(sub(resultPtr, 2), shl(240, 0x3d3d)) }
      case 2 { mstore(sub(resultPtr, 1), shl(248, 0x3d)) }
    }
    
    return result;
  }
}