Squirrelly Squirrels Official Collection

// Sources flattened with hardhat v2.8.3 https://hardhat.org

// File @openzeppelin/contracts/utils/cryptography/MerkleProof.sol@v4.4.2

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/cryptography/MerkleProof.sol)

pragma solidity ^0.8.0;

/**
 * @dev These functions deal with verification of Merkle Trees proofs.
 *
 * The proofs can be generated using the JavaScript library
 * https://github.com/miguelmota/merkletreejs[merkletreejs].
 * Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.
 *
 * See `test/utils/cryptography/MerkleProof.test.js` for some examples.
 */
library MerkleProof {
  /**
   * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
   * defined by `root`. For this, a `proof` must be provided, containing
   * sibling hashes on the branch from the leaf to the root of the tree. Each
   * pair of leaves and each pair of pre-images are assumed to be sorted.
   */
  function verify(
    bytes32[] memory proof,
    bytes32 root,
    bytes32 leaf
  ) internal pure returns (bool) {
    return processProof(proof, leaf) == root;
  }

  /**
   * @dev Returns the rebuilt hash obtained by traversing a Merklee tree up
   * from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
   * hash matches the root of the tree. When processing the proof, the pairs
   * of leafs & pre-images are assumed to be sorted.
   *
   * _Available since v4.4._
   */
  function processProof(bytes32[] memory proof, bytes32 leaf)
    internal
    pure
    returns (bytes32)
  {
    bytes32 computedHash = leaf;
    for (uint256 i = 0; i < proof.length; i++) {
      bytes32 proofElement = proof[i];
      if (computedHash <= proofElement) {
        // Hash(current computed hash + current element of the proof)
        computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
      } else {
        // Hash(current element of the proof + current computed hash)
        computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
      }
    }
    return computedHash;
  }
}

// File @openzeppelin/contracts/utils/Context.sol@v4.4.2

// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

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

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

// File @openzeppelin/contracts/access/Ownable.sol@v4.4.2

// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)

pragma solidity ^0.8.0;

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

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

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

// File @chainlink/contracts/src/v0.8/interfaces/LinkTokenInterface.sol@v0.3.1

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 @chainlink/contracts/src/v0.8/VRFRequestIDBase.sol@v0.3.1

pragma solidity ^0.8.0;

contract VRFRequestIDBase {
  /**
   * @notice returns the seed which is actually input to the VRF coordinator
   *
   * @dev To prevent repetition of VRF output due to repetition of the
   * @dev user-supplied seed, that seed is combined in a hash with the
   * @dev user-specific nonce, and the address of the consuming contract. The
   * @dev risk of repetition is mostly mitigated by inclusion of a blockhash in
   * @dev the final seed, but the nonce does protect against repetition in
   * @dev requests which are included in a single block.
   *
   * @param _userSeed VRF seed input provided by user
   * @param _requester Address of the requesting contract
   * @param _nonce User-specific nonce at the time of the request
   */
  function makeVRFInputSeed(
    bytes32 _keyHash,
    uint256 _userSeed,
    address _requester,
    uint256 _nonce
  ) internal pure returns (uint256) {
    return
      uint256(keccak256(abi.encode(_keyHash, _userSeed, _requester, _nonce)));
  }

  /**
   * @notice Returns the id for this request
   * @param _keyHash The serviceAgreement ID to be used for this request
   * @param _vRFInputSeed The seed to be passed directly to the VRF
   * @return The id for this request
   *
   * @dev Note that _vRFInputSeed is not the seed passed by the consuming
   * @dev contract, but the one generated by makeVRFInputSeed
   */
  function makeRequestId(bytes32 _keyHash, uint256 _vRFInputSeed)
    internal
    pure
    returns (bytes32)
  {
    return keccak256(abi.encodePacked(_keyHash, _vRFInputSeed));
  }
}

// File @chainlink/contracts/src/v0.8/VRFConsumerBase.sol@v0.3.1

pragma solidity ^0.8.0;

/** ****************************************************************************
 * @notice Interface for contracts using VRF randomness
 * *****************************************************************************
 * @dev PURPOSE
 *
 * @dev Reggie the Random Oracle (not his real job) wants to provide randomness
 * @dev to Vera the verifier in such a way that Vera can be sure he's not
 * @dev making his output up to suit himself. Reggie provides Vera a public key
 * @dev to which he knows the secret key. Each time Vera provides a seed to
 * @dev Reggie, he gives back a value which is computed completely
 * @dev deterministically from the seed and the secret key.
 *
 * @dev Reggie provides a proof by which Vera can verify that the output was
 * @dev correctly computed once Reggie tells it to her, but without that proof,
 * @dev the output is indistinguishable to her from a uniform random sample
 * @dev from the output space.
 *
 * @dev The purpose of this contract is to make it easy for unrelated contracts
 * @dev to talk to Vera the verifier about the work Reggie is doing, to provide
 * @dev simple access to a verifiable source of randomness.
 * *****************************************************************************
 * @dev USAGE
 *
 * @dev Calling contracts must inherit from VRFConsumerBase, and can
 * @dev initialize VRFConsumerBase's attributes in their constructor as
 * @dev shown:
 *
 * @dev   contract VRFConsumer {
 * @dev     constuctor(<other arguments>, address _vrfCoordinator, address _link)
 * @dev       VRFConsumerBase(_vrfCoordinator, _link) public {
 * @dev         <initialization with other arguments goes here>
 * @dev       }
 * @dev   }
 *
 * @dev The oracle will have given you an ID for the VRF keypair they have
 * @dev committed to (let's call it keyHash), and have told you the minimum LINK
 * @dev price for VRF service. Make sure your contract has sufficient LINK, and
 * @dev call requestRandomness(keyHash, fee, seed), where seed is the input you
 * @dev want to generate randomness from.
 *
 * @dev Once the VRFCoordinator has received and validated the oracle's response
 * @dev to your request, it will call your contract's fulfillRandomness method.
 *
 * @dev The randomness argument to fulfillRandomness is the actual random value
 * @dev generated from your seed.
 *
 * @dev The requestId argument is generated from the keyHash and the seed by
 * @dev makeRequestId(keyHash, seed). If your contract could have concurrent
 * @dev requests open, you can use the requestId to track which seed is
 * @dev associated with which randomness. See VRFRequestIDBase.sol for more
 * @dev details. (See "SECURITY CONSIDERATIONS" for principles to keep in mind,
 * @dev if your contract could have multiple requests in flight simultaneously.)
 *
 * @dev Colliding `requestId`s are cryptographically impossible as long as seeds
 * @dev differ. (Which is critical to making unpredictable randomness! See the
 * @dev next section.)
 *
 * *****************************************************************************
 * @dev SECURITY CONSIDERATIONS
 *
 * @dev A method with the ability to call your fulfillRandomness method directly
 * @dev could spoof a VRF response with any random value, so it's critical that
 * @dev it cannot be directly called by anything other than this base contract
 * @dev (specifically, by the VRFConsumerBase.rawFulfillRandomness method).
 *
 * @dev For your users to trust that your contract's random behavior is free
 * @dev from malicious interference, it's best if you can write it so that all
 * @dev behaviors implied by a VRF response are executed *during* your
 * @dev fulfillRandomness method. If your contract must store the response (or
 * @dev anything derived from it) and use it later, you must ensure that any
 * @dev user-significant behavior which depends on that stored value cannot be
 * @dev manipulated by a subsequent VRF request.
 *
 * @dev Similarly, both miners and the VRF oracle itself have some influence
 * @dev over the order in which VRF responses appear on the blockchain, so if
 * @dev your contract could have multiple VRF requests in flight simultaneously,
 * @dev you must ensure that the order in which the VRF responses arrive cannot
 * @dev be used to manipulate your contract's user-significant behavior.
 *
 * @dev Since the ultimate input to the VRF is mixed with the block hash of the
 * @dev block in which the request is made, user-provided seeds have no impact
 * @dev on its economic security properties. They are only included for API
 * @dev compatability with previous versions of this contract.
 *
 * @dev Since the block hash of the block which contains the requestRandomness
 * @dev call is mixed into the input to the VRF *last*, a sufficiently powerful
 * @dev miner could, in principle, fork the blockchain to evict the block
 * @dev containing the request, forcing the request to be included in a
 * @dev different block with a different hash, and therefore a different input
 * @dev to the VRF. However, such an attack would incur a substantial economic
 * @dev cost. This cost scales with the number of blocks the VRF oracle waits
 * @dev until it calls responds to a request.
 */
abstract contract VRFConsumerBase is VRFRequestIDBase {
  /**
   * @notice fulfillRandomness handles the VRF response. Your contract must
   * @notice implement it. See "SECURITY CONSIDERATIONS" above for important
   * @notice principles to keep in mind when implementing your fulfillRandomness
   * @notice method.
   *
   * @dev VRFConsumerBase expects its subcontracts to have a method with this
   * @dev signature, and will call it once it has verified the proof
   * @dev associated with the randomness. (It is triggered via a call to
   * @dev rawFulfillRandomness, below.)
   *
   * @param requestId The Id initially returned by requestRandomness
   * @param randomness the VRF output
   */
  function fulfillRandomness(bytes32 requestId, uint256 randomness)
    internal
    virtual;

  /**
   * @dev In order to keep backwards compatibility we have kept the user
   * seed field around. We remove the use of it because given that the blockhash
   * enters later, it overrides whatever randomness the used seed provides.
   * Given that it adds no security, and can easily lead to misunderstandings,
   * we have removed it from usage and can now provide a simpler API.
   */
  uint256 private constant USER_SEED_PLACEHOLDER = 0;

  /**
   * @notice requestRandomness initiates a request for VRF output given _seed
   *
   * @dev The fulfillRandomness method receives the output, once it's provided
   * @dev by the Oracle, and verified by the vrfCoordinator.
   *
   * @dev The _keyHash must already be registered with the VRFCoordinator, and
   * @dev the _fee must exceed the fee specified during registration of the
   * @dev _keyHash.
   *
   * @dev The _seed parameter is vestigial, and is kept only for API
   * @dev compatibility with older versions. It can't *hurt* to mix in some of
   * @dev your own randomness, here, but it's not necessary because the VRF
   * @dev oracle will mix the hash of the block containing your request into the
   * @dev VRF seed it ultimately uses.
   *
   * @param _keyHash ID of public key against which randomness is generated
   * @param _fee The amount of LINK to send with the request
   *
   * @return requestId unique ID for this request
   *
   * @dev The returned requestId can be used to distinguish responses to
   * @dev concurrent requests. It is passed as the first argument to
   * @dev fulfillRandomness.
   */
  function requestRandomness(bytes32 _keyHash, uint256 _fee)
    internal
    returns (bytes32 requestId)
  {
    LINK.transferAndCall(
      vrfCoordinator,
      _fee,
      abi.encode(_keyHash, USER_SEED_PLACEHOLDER)
    );
    // This is the seed passed to VRFCoordinator. The oracle will mix this with
    // the hash of the block containing this request to obtain the seed/input
    // which is finally passed to the VRF cryptographic machinery.
    uint256 vRFSeed = makeVRFInputSeed(
      _keyHash,
      USER_SEED_PLACEHOLDER,
      address(this),
      nonces[_keyHash]
    );
    // nonces[_keyHash] must stay in sync with
    // VRFCoordinator.nonces[_keyHash][this], which was incremented by the above
    // successful LINK.transferAndCall (in VRFCoordinator.randomnessRequest).
    // This provides protection against the user repeating their input seed,
    // which would result in a predictable/duplicate output, if multiple such
    // requests appeared in the same block.
    nonces[_keyHash] = nonces[_keyHash] + 1;
    return makeRequestId(_keyHash, vRFSeed);
  }

  LinkTokenInterface internal immutable LINK;
  address private immutable vrfCoordinator;

  // Nonces for each VRF key from which randomness has been requested.
  //
  // Must stay in sync with VRFCoordinator[_keyHash][this]
  mapping(bytes32 => uint256) /* keyHash */ /* nonce */
    private nonces;

  /**
   * @param _vrfCoordinator address of VRFCoordinator contract
   * @param _link address of LINK token contract
   *
   * @dev https://docs.chain.link/docs/link-token-contracts
   */
  constructor(address _vrfCoordinator, address _link) {
    vrfCoordinator = _vrfCoordinator;
    LINK = LinkTokenInterface(_link);
  }

  // rawFulfillRandomness is called by VRFCoordinator when it receives a valid VRF
  // proof. rawFulfillRandomness then calls fulfillRandomness, after validating
  // the origin of the call
  function rawFulfillRandomness(bytes32 requestId, uint256 randomness)
    external
  {
    require(msg.sender == vrfCoordinator, "Only VRFCoordinator can fulfill");
    fulfillRandomness(requestId, randomness);
  }
}

// File @openzeppelin/contracts/utils/introspection/IERC165.sol@v4.4.2

// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

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

// File @openzeppelin/contracts/token/ERC721/IERC721.sol@v4.4.2

// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

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

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

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

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

// File @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol@v4.4.2

// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

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

// File @openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol@v4.4.2

// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)

pragma solidity ^0.8.0;

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

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

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

// File @openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol@v4.4.2

// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Enumerable.sol)

pragma solidity ^0.8.0;

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

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

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

// File @openzeppelin/contracts/utils/Address.sol@v4.4.2

// OpenZeppelin Contracts v4.4.1 (utils/Address.sol)

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

// File @openzeppelin/contracts/utils/Strings.sol@v4.4.2

// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)

pragma solidity ^0.8.0;

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

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

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

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

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

// File @openzeppelin/contracts/utils/introspection/ERC165.sol@v4.4.2

// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)

pragma solidity ^0.8.0;

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

// File contracts/token/ERC721/ERC721.sol

// Creators: locationtba.eth, 2pmflow.eth

pragma solidity ^0.8.0;

/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata and Enumerable extension. Built to optimize for lower gas during batch mints.
 *
 * Assumes serials are sequentially minted starting at 0 (e.g. 0, 1, 2, 3..).
 *
 * Does not support burning tokens to address(0).
 */
abstract contract ERC721 is
  Context,
  ERC165,
  IERC721,
  IERC721Metadata,
  IERC721Enumerable
{
  using Address for address;
  using Strings for uint256;

  struct TokenOwnership {
    address addr;
    uint64 startTimestamp;
  }

  struct AddressData {
    uint128 balance;
    uint128 numberMinted;
  }

  uint256 private currentIndex = 0;

  uint256 internal immutable maxBatchSize;

  // Token name
  string private _name;

  // Token symbol
  string private _symbol;

  // Mapping from token ID to ownership details
  // An empty struct value does not necessarily mean the token is unowned. See ownershipOf implementation for details.
  mapping(uint256 => TokenOwnership) private _ownerships;

  // Mapping owner address to address data
  mapping(address => AddressData) private _addressData;

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

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

  /**
   * @dev
   * `maxBatchSize` refers to how much a minter can mint at a time.
   */
  constructor(
    string memory name_,
    string memory symbol_,
    uint256 maxBatchSize_
  ) {
    require(maxBatchSize_ > 0, "ERC721: max batch size must be nonzero");
    _name = name_;
    _symbol = symbol_;
    maxBatchSize = maxBatchSize_;
  }

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

  /**
   * @dev See {IERC721Enumerable-tokenByIndex}.
   */
  function tokenByIndex(uint256 index) public view override returns (uint256) {
    require(index < totalSupply(), "ERC721: global index out of bounds");
    return index;
  }

  /**
   * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
   * This read function is O(totalSupply). If calling from a separate contract, be sure to test gas first.
   * It may also degrade with extremely large collection sizes (e.g >> 10000), test for your use case.
   */
  function tokenOfOwnerByIndex(address owner, uint256 index)
    public
    view
    override
    returns (uint256)
  {
    require(index < balanceOf(owner), "ERC721: owner index out of bounds");
    uint256 numMintedSoFar = totalSupply();
    uint256 tokenIdsIdx = 0;
    address currOwnershipAddr = address(0);
    for (uint256 i = 0; i < numMintedSoFar; i++) {
      TokenOwnership memory ownership = _ownerships[i];
      if (ownership.addr != address(0)) {
        currOwnershipAddr = ownership.addr;
      }
      if (currOwnershipAddr == owner) {
        if (tokenIdsIdx == index) {
          return i;
        }
        tokenIdsIdx++;
      }
    }
    revert("ERC721: unable to get token of owner by index");
  }

  /**
   * @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 ||
      interfaceId == type(IERC721Enumerable).interfaceId ||
      super.supportsInterface(interfaceId);
  }

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

  function _numberMinted(address owner) internal view returns (uint256) {
    require(
      owner != address(0),
      "ERC721: number minted query for the zero address"
    );
    return uint256(_addressData[owner].numberMinted);
  }

  function ownershipOf(uint256 tokenId)
    internal
    view
    returns (TokenOwnership memory)
  {
    require(_exists(tokenId), "ERC721: owner query for nonexistent token");

    uint256 lowestTokenToCheck;
    if (tokenId >= maxBatchSize) {
      lowestTokenToCheck = tokenId - maxBatchSize + 1;
    }

    for (uint256 curr = tokenId; curr >= lowestTokenToCheck; curr--) {
      TokenOwnership memory ownership = _ownerships[curr];
      if (ownership.addr != address(0)) {
        return ownership;
      }
    }

    revert("ERC721: unable to determine the owner of token");
  }

  /**
   * @dev See {IERC721-ownerOf}.
   */
  function ownerOf(uint256 tokenId) public view override returns (address) {
    return ownershipOf(tokenId).addr;
  }

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

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

  /**
   * @dev See {IERC721Metadata-tokenURI}.
   */
  function tokenURI(uint256 tokenId)
    public
    view
    virtual
    override
    returns (string memory)
  {
    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 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, owner);
  }

  /**
   * @dev See {IERC721-getApproved}.
   */
  function getApproved(uint256 tokenId) public view 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 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 override {
    _transfer(from, to, tokenId);
  }

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

  /**
   * @dev See {IERC721-safeTransferFrom}.
   */
  function safeTransferFrom(
    address from,
    address to,
    uint256 tokenId,
    bytes memory _data
  ) public override {
    _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`),
   */
  function _exists(uint256 tokenId) internal view returns (bool) {
    return tokenId < currentIndex;
  }

  function _safeMint(address to, uint256 quantity) internal {
    _safeMint(to, quantity, "");
  }

  /**
   * @dev Mints `quantity` tokens and transfers them to `to`.
   *
   * Requirements:
   *
   * - `to` cannot be the zero address.
   * - `quantity` cannot be larger than the max batch size.
   *
   * Emits a {Transfer} event.
   */
  function _safeMint(
    address to,
    uint256 quantity,
    bytes memory _data
  ) internal {
    uint256 startTokenId = currentIndex;
    require(to != address(0), "ERC721: mint to the zero address");
    // We know if the first token in the batch doesn't exist, the other ones don't as well, because of serial ordering.
    require(!_exists(startTokenId), "ERC721: token already minted");
    require(quantity <= maxBatchSize, "ERC721: quantity to mint too high");

    _beforeTokenTransfers(address(0), to, startTokenId, quantity);

    AddressData memory addressData = _addressData[to];
    _addressData[to] = AddressData(
      addressData.balance + uint128(quantity),
      addressData.numberMinted + uint128(quantity)
    );
    _ownerships[startTokenId] = TokenOwnership(to, uint64(block.timestamp));

    uint256 updatedIndex = startTokenId;

    for (uint256 i = 0; i < quantity; i++) {
      emit Transfer(address(0), to, updatedIndex);
      require(
        _checkOnERC721Received(address(0), to, updatedIndex, _data),
        "ERC721: transfer to non ERC721Receiver implementer"
      );
      updatedIndex++;
    }

    currentIndex = updatedIndex;
    _afterTokenTransfers(address(0), to, startTokenId, quantity);
  }

  /**
   * @dev Transfers `tokenId` from `from` to `to`.
   *
   * Requirements:
   *
   * - `to` cannot be the zero address.
   * - `tokenId` token must be owned by `from`.
   *
   * Emits a {Transfer} event.
   */
  function _transfer(
    address from,
    address to,
    uint256 tokenId
  ) private {
    TokenOwnership memory prevOwnership = ownershipOf(tokenId);

    bool isApprovedOrOwner = (_msgSender() == prevOwnership.addr ||
      getApproved(tokenId) == _msgSender() ||
      isApprovedForAll(prevOwnership.addr, _msgSender()));

    require(
      isApprovedOrOwner,
      "ERC721: transfer caller is not owner nor approved"
    );

    require(
      prevOwnership.addr == from,
      "ERC721: transfer from incorrect owner"
    );
    require(to != address(0), "ERC721: transfer to the zero address");

    _beforeTokenTransfers(from, to, tokenId, 1);

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

    _addressData[from].balance -= 1;
    _addressData[to].balance += 1;
    _ownerships[tokenId] = TokenOwnership(to, uint64(block.timestamp));

    // If the ownership slot of tokenId+1 is not explicitly set, that means the transfer initiator owns it.
    // Set the slot of tokenId+1 explicitly in storage to maintain correctness for ownerOf(tokenId+1) calls.
    uint256 nextTokenId = tokenId + 1;
    if (_ownerships[nextTokenId].addr == address(0)) {
      if (_exists(nextTokenId)) {
        _ownerships[nextTokenId] = TokenOwnership(
          prevOwnership.addr,
          prevOwnership.startTimestamp
        );
      }
    }

    emit Transfer(from, to, tokenId);
    _afterTokenTransfers(from, to, tokenId, 1);
  }

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

  uint256 public nextOwnerToExplicitlySet = 0;

  /**
   * @dev Explicitly set `owners` to eliminate loops in future calls of ownerOf().
   */
  function _setOwnersExplicit(uint256 quantity) internal {
    uint256 oldNextOwnerToSet = nextOwnerToExplicitlySet;
    require(quantity > 0, "quantity must be nonzero");
    uint256 endIndex = oldNextOwnerToSet + quantity - 1;
    if (endIndex > currentIndex - 1) {
      endIndex = currentIndex - 1;
    }
    // We know if the last one in the group exists, all in the group exist, due to serial ordering.
    require(_exists(endIndex), "not enough minted yet for this cleanup");
    for (uint256 i = oldNextOwnerToSet; i <= endIndex; i++) {
      if (_ownerships[i].addr == address(0)) {
        TokenOwnership memory ownership = ownershipOf(i);
        _ownerships[i] = TokenOwnership(
          ownership.addr,
          ownership.startTimestamp
        );
      }
    }
    nextOwnerToExplicitlySet = endIndex + 1;
  }

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

  /**
   * @dev Hook that is called before a set of serially-ordered token ids are about to be transferred. This includes minting.
   *
   * startTokenId - the first token id to be transferred
   * quantity - the amount to be transferred
   *
   * Calling conditions:
   *
   * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
   * transferred to `to`.
   * - When `from` is zero, `tokenId` will be minted for `to`.
   */
  function _beforeTokenTransfers(
    address from,
    address to,
    uint256 startTokenId,
    uint256 quantity
  ) internal virtual {}

  /**
   * @dev Hook that is called after a set of serially-ordered token ids have been transferred. This includes
   * minting.
   *
   * startTokenId - the first token id to be transferred
   * quantity - the amount to be transferred
   *
   * Calling conditions:
   *
   * - when `from` and `to` are both non-zero.
   * - `from` and `to` are never both zero.
   */
  function _afterTokenTransfers(
    address from,
    address to,
    uint256 startTokenId,
    uint256 quantity
  ) internal virtual {}
}

// File contracts/SquirrellySquirrels.sol

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// \___ \| | | | | | || || |_) | |_) |  _| | |   | |  \ V /
//  ___) | |_| | |_| || ||  _ <|  _ <| |___| |___| |___| |
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//   / ___| / _ \| | | |_ _|  _ \|  _ \| ____| |   / ___|
//   \___ \| | | | | | || || |_) | |_) |  _| | |   \___ \
//    ___) | |_| | |_| || ||  _ <|  _ <| |___| |___ ___) |
//   |____/ \__\_\\___/|___|_| \_\_| \_\_____|_____|____/

pragma solidity ^0.8.0;

contract SquirrellySquirrels is VRFConsumerBase, ERC721, Ownable {
  using Strings for uint256;

  uint256 public constant NFT_1_PRICE = 0.16 ether;
  uint256 public constant NFT_3_PRICE = 0.39 ether;
  uint256 public constant NFT_5_PRICE = 0.45 ether;
  uint256 public constant MAX_NFT_PURCHASE_PRESALE = 5;
  uint256 public constant MAX_MINT_PER_TX = 5;
  uint256 public constant MAX_SUPPLY = 10000;

  bool public saleIsActive = false;
  bool public presaleIsActive = false;

  bool public revealed = false;

  uint256 public reserve = 300;
  uint256 public startingIndex;

  mapping(address => uint256) public allowListNumClaimed;
  bytes32 public allowListMerkleRoot;
  bytes32 public startingIndexRequestId;

  string public uriPrefix = "";
  string public uriSuffix = ".json";
  string public hiddenMetadataUri = "";
  string public provenance;

  string private _baseURIExtended;

  modifier mintCompliance(uint256 _numberOfTokens) {
    require(
      _numberOfTokens > 0 &&
        _numberOfTokens != 2 &&
        _numberOfTokens != 4 &&
        _numberOfTokens <= MAX_MINT_PER_TX,
      "Invalid mint amount"
    );

    require(
      (_numberOfTokens == 1 && msg.value == NFT_1_PRICE) ||
        (_numberOfTokens == 3 && msg.value == NFT_3_PRICE) ||
        (_numberOfTokens == 5 && msg.value == NFT_5_PRICE),
      "Sent ether value is incorrect"
    );

    _;
  }

  constructor(
    address _vrfCoordinator,
    address _link,
    address _owner
  )
    ERC721("Squirrelly Squirrels", "SQRLY", 300)
    VRFConsumerBase(_vrfCoordinator, _link)
  {
    transferOwnership(_owner);
  }

  function requestStartingIndex(bytes32 _keyHash, uint256 _fee)
    external
    onlyOwner
    returns (bytes32 requestId)
  {
    require(startingIndex == 0, "startingIndex has already been set");
    bytes32 _requestId = requestRandomness(_keyHash, _fee);
    startingIndexRequestId = _requestId;
    return _requestId;
  }

  function fulfillRandomness(bytes32 _requestId, uint256 _randomness)
    internal
    override
  {
    if (startingIndexRequestId == _requestId) {
      startingIndex = _randomness % MAX_SUPPLY;
    }
  }

  function claimReserve(address _to, uint256 _reserveAmount)
    external
    onlyOwner
  {
    require(
      _reserveAmount > 0 && _reserveAmount <= reserve,
      "Not enough reserve left for team"
    );

    reserve = reserve - _reserveAmount;

    _safeMint(_to, _reserveAmount);
  }

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

  function flipPresaleState() external onlyOwner {
    presaleIsActive = !presaleIsActive;
  }

  function isAllowListed(bytes32[] memory _proof, address _address)
    public
    view
    returns (bool)
  {
    require(_address != address(0), "Zero address not on Allow List");

    bytes32 leaf = keccak256(abi.encodePacked(_address));
    return MerkleProof.verify(_proof, allowListMerkleRoot, leaf);
  }

  function setAllowListMerkleRoot(bytes32 _allowListMerkleRoot)
    external
    onlyOwner
  {
    allowListMerkleRoot = _allowListMerkleRoot;
  }

  function mintPresale(bytes32[] memory _proof, uint256 _numberOfTokens)
    external
    payable
    mintCompliance(_numberOfTokens)
  {
    require(presaleIsActive, "Presale is not active at the moment");
    require(
      isAllowListed(_proof, msg.sender),
      "This address is not allow listed for the presale"
    );
    require(
      allowListNumClaimed[msg.sender] + _numberOfTokens <=
        MAX_NFT_PURCHASE_PRESALE,
      "Exceeds allowed presale you can mint"
    );
    require(
      totalSupply() + _numberOfTokens <= MAX_SUPPLY - reserve,
      "Purchase would exceed max supply"
    );

    _safeMint(msg.sender, _numberOfTokens);

    allowListNumClaimed[msg.sender] += _numberOfTokens;
  }

  function mint(uint256 _numberOfTokens)
    external
    payable
    mintCompliance(_numberOfTokens)
  {
    require(saleIsActive, "Sale is not active at the moment");
    require(
      totalSupply() + _numberOfTokens <= MAX_SUPPLY - reserve,
      "Purchase would exceed max supply"
    );

    _safeMint(msg.sender, _numberOfTokens);
  }

  function walletOfOwner(address _owner)
    external
    view
    returns (uint256[] memory)
  {
    uint256 ownerTokenCount = balanceOf(_owner);
    uint256[] memory ownedTokenIds = new uint256[](ownerTokenCount);

    for (uint256 i = 0; i < ownerTokenCount; i++) {
      ownedTokenIds[i] = tokenOfOwnerByIndex(_owner, i);
    }

    return ownedTokenIds;
  }

  function tokenURI(uint256 _tokenId)
    public
    view
    virtual
    override
    returns (string memory)
  {
    require(
      _exists(_tokenId),
      "ERC721Metadata: URI query for nonexistent token"
    );

    if (revealed == false) {
      return hiddenMetadataUri;
    }

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

  function setHiddenMetadataUri(string memory _hiddenMetadataUri)
    external
    onlyOwner
  {
    hiddenMetadataUri = _hiddenMetadataUri;
  }

  function setUriPrefix(string memory _uriPrefix) external onlyOwner {
    uriPrefix = _uriPrefix;
  }

  function setUriSuffix(string memory _uriSuffix) external onlyOwner {
    uriSuffix = _uriSuffix;
  }

  function setRevealed(bool _state) external onlyOwner {
    revealed = _state;
  }

  function setProvenance(string calldata _provenance) external onlyOwner {
    provenance = _provenance;
  }

  function withdraw() external onlyOwner {
    (bool os, ) = payable(owner()).call{ value: address(this).balance }("");
    require(os, "withdraw: transfer failed");
  }

  function _baseURI() internal view virtual override returns (string memory) {
    return uriPrefix;
  }
}

{
  "compilationTarget": {
    "SquirrellySquirrels.sol": "SquirrellySquirrels"
  },
  "evmVersion": "istanbul",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": []
}