// File: /Users/kokleongseow/Documents/PROJECTS/METAKAWS-contract/contracts/METAKAYS.sol



// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.0;
import "base64-sol/base64.sol";
import "./ERC721.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import { MerkleProof } from "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";

interface IFeatures1 {
  function readMisc(uint256 _id) external view returns (string memory);
}

interface IFeatures2{
  function readMouth(uint256 _id) external view returns (string memory);
}

interface IFeatures3 {
  function readHair(uint256 _id) external view returns (string memory);
}

contract METAKAYS is Ownable, ERC721 {

    event Kustomized(uint256 _itemID);

    struct Features {
      uint8 backgroundColor;
      uint8 bodyColor;
      uint8 skinColor;
      uint8 hairColor;
      uint8 mouthColor;
      uint8 hairStyle;
      uint8 mouthStyle;
      uint8 miscStyle1;
      uint8 miscStyle1Color;
      uint8 miscStyle2;
      uint8 miscStyle2Color;
      uint8 eyesColor;
      string customText;
    }

    IFeatures1 features1;
    IFeatures2 features2;
    IFeatures3 features3;

    uint256 public constant AMOUNT_FOR_METAKOUNCIL = 280;
    uint256 public constant price = 0.08888 ether;

    bytes32 public _merkleRoot;
    bool public _saleIsActive = false;

    mapping(uint256 => Features) public features;
    mapping (uint256 => string) public svgBackgroundColor;
    mapping (uint256 => bool) public finality;
    mapping (address => bool) public whitelistClaimed;

    constructor()
    ERC721("METAKAYS", "K", 5, 8888) {
      svgBackgroundColor[0] = '#2dd055"/>';
      svgBackgroundColor[1] = '#09a137"/>';
      svgBackgroundColor[2] = '#065535"/>';
      svgBackgroundColor[3] = '#88b04b"/>';
      svgBackgroundColor[4] = '#00ffff"/>';
      svgBackgroundColor[5] = '#5acef3"/>';
      svgBackgroundColor[6] = '#0050ff"/>';
      svgBackgroundColor[7] = '#4559cc"/>';
      svgBackgroundColor[8] = '#34568b"/>';
      svgBackgroundColor[9] = '#8a2be2"/>';
      svgBackgroundColor[10] = '#6b5b95"/>';
      svgBackgroundColor[11] = '#b565a7"/>';
      svgBackgroundColor[12] = '#ff80ed"/>';
      svgBackgroundColor[13] = '#ffc0cb"/>';
      svgBackgroundColor[14] = '#faceac"/>';
      svgBackgroundColor[15] = '#dfff00"/>';
      svgBackgroundColor[16] = '#fff300"/>';
      svgBackgroundColor[17] = '#ffd700"/>';
      svgBackgroundColor[18] = '#ffa500"/>';
      svgBackgroundColor[19] = '#896258"/>';
      svgBackgroundColor[20] = '#945610"/>';
      svgBackgroundColor[21] = '#9b2335"/>';
      svgBackgroundColor[22] = '#b14044"/>';
      svgBackgroundColor[23] = '#ff0000"/>';
      svgBackgroundColor[24] = '#df1b49"/>';
      svgBackgroundColor[25] = '#f71863"/>';
      svgBackgroundColor[26] = '#928e8e"/>';
      svgBackgroundColor[27] = '#ffffff"/>';
      svgBackgroundColor[28] = '#000000"/>';
    }

    function setSaleIsActive(bool saleIsActive) external onlyOwner {
      _saleIsActive = saleIsActive;
    }

    function setPresaleMerkleRoot(bytes32 root) external onlyOwner {
      _merkleRoot = root;
    }

    //RENOUNCE/TRANSFER @ 616.
    function setFeaturesAddress(address[] memory addr) external onlyOwner{
      features1= IFeatures1(addr[0]);
      features2 = IFeatures2(addr[1]);
      features3 = IFeatures3(addr[2]);
    }

    function kustomize(uint256 _itemID, uint8[] memory selection_, string memory _customText) public {
      require(msg.sender == ownerOf(_itemID), "YOU ARE NOT THE OWNER!");
      require(customShirtCheck(_customText) == true, "PLEASE ONLY USE 1-8 CAPITAL LETTERS!");
      require(finality[_itemID] == false, "FINALITY!");
      require((selection_[0] < 29) && (selection_[1] < 29) && (selection_[2] < 29) && (selection_[3] < 29) &&
      (selection_[4] < 29) && (selection_[5] < 29) && (selection_[6] < 29) && (selection_[7] < 29) &&
      (selection_[8] < 29) && (selection_[9] < 29) && (selection_[10] < 29) && (selection_[11] < 29), "NO SUCH FEATURE!");
      Features storage feature = features[_itemID];
      feature.backgroundColor = selection_[0];
      feature.bodyColor = selection_[1];
      feature.skinColor = selection_[2];
      feature.hairColor = selection_[3];
      feature.mouthColor = selection_[4];
      feature.hairStyle = selection_[5];
      feature.mouthStyle = selection_[6];
      feature.miscStyle1 = selection_[7];
      feature.miscStyle1Color = selection_[8];
      feature.miscStyle2 = selection_[9];
      feature.miscStyle2Color = selection_[10];
      feature.eyesColor = selection_[11];
      feature.customText = _customText;
      emit Kustomized(_itemID);
    }

    function setFinality(uint256 _itemID) public {
      require(msg.sender == ownerOf(_itemID), "YOU ARE NOT THE OWNER!");
      finality[_itemID] = true;
    }

    function publicClaim(uint256 quantity) external payable {
      require(_saleIsActive,"SALE IS NOT ACTIVE!");
      require(totalSupply() + quantity <= collectionSize, "MAX SUPPLY!");
      require(quantity * price <= msg.value, "INCORRECT AMOUNT SENT!");
      _safeMint(msg.sender, quantity);
    }

    function whitelistClaim(uint256 _amount, bytes32[] calldata _merkleProof) external payable {
      require(!whitelistClaimed[msg.sender], "ADDRESS HAS ALREADY CLAIMED!");
      require(totalSupply() + _amount <= collectionSize, "MAX SUPPLY!");
      require(_amount * price <= msg.value, "INCORRECT AMOUNT SENT!");
      bytes32 leaf = keccak256(abi.encodePacked(msg.sender));
      require(MerkleProof.verify(_merkleProof, _merkleRoot, leaf),  "INVALID PROOF!");
      whitelistClaimed[msg.sender] = true;
      _safeMint(msg.sender, _amount);
    }

    function devMint(uint256 quantity) external onlyOwner {
      require(totalSupply() + quantity <= AMOUNT_FOR_METAKOUNCIL, "TOO MANY ALREADY MINTED!");
      require(quantity % maxBatchSize == 0, "CAN ONLY MINT A MULTIPLE OF MAXBATCHSIZE!");
      uint256 numChunks = quantity / maxBatchSize;
      for (uint256 i = 0; i < numChunks; i++) {
        _safeMint(msg.sender, maxBatchSize);
      }
    }

    function withdrawMoney() external onlyOwner {
      (bool success, ) = msg.sender.call{value: address(this).balance}("");
      require(success, "WITHDRAW FAILED!");
    }

    function tokenURI(uint256 _tokenId) public view virtual override returns (string memory) {
      require(_exists(_tokenId), "ERC721Metadata: URI query for nonexistent token");
      Features memory feature = features[_tokenId];
      string memory tokenIdString = toString(_tokenId);
      string memory _first = concatenate(
        '<svg version="1.0" xmlns="http://www.w3.org/2000/svg" width="888.000000pt" height="888.000000pt" viewBox="0 0 888.000000 888.000000" preserveAspectRatio="xMidYMid meet"> <g transform="translate(0.000000,888.000000) scale(0.100000,-0.100000)"> <path d="M0 4440 l0 -4440 4440 0 4440 0 0 4440 0 4440 -4440 0 -4440 0 0 -4440z" fill="',
        svgBackgroundColor[feature.backgroundColor], '<path d="M3530 3270 l0 -130 -395 0 -395 0 0 -130 0 -130 -515 0 -515 0 0 -130 0 -130 -130 0 -130 0 0 -1310 0 -1310 130 0 130 0 0 1310 0 1310 515 0 515 0 0 130 0 130 395 0 395 0 0 130 0 130 910 0 910 0 0 -130 0 -130 395 0 395 0 0 -130 0 -130 515 0 515 0 0 -1310 0 -1310 130 0 130 0 0 1310 0 1310 -130 0 -130 0 0 130 0 130 -515 0 -515 0 0 130 0 130 -395 0 -395 0 0 130 0 130 -910 0 -910 0 0 -130z M2610 660 l0 -660 130 0 130 0 0 660 0 660 -130 0 -130 0 0 -660z M6010 660 l0 -660 130 0 130 0 0 660 0 660 -130 0 -130 0 0 -660z"/> <path d="M3530 3010 l0 -130 -395 0 -395 0 0 -130 0 -130 -515 0 -515 0 0 -1310 0 -1310 450 0 450 0 0 660 0 660 130 0 130 0 0 -660 0 -660 1570 0 1570 0 0 660 0 660 130 0 130 0 0 -660 0 -660 450 0 450 0 0 1310 0 1310 -515 0 -515 0 0 130 0 130 -395 0 -395 0 0 130 0 130 -910 0 -910 0 0 -130z" fill="',
        svgBackgroundColor[feature.bodyColor],'<g transform="translate(0.000000,888.000000) scale(0.100000,-0.100000)"><text x="44488" y="-8800" font-size="4800px" font-family="impact" font-weight="bold" dominant-baseline="middle" text-anchor="middle">',
        feature.customText,
        '</text></g><g transform="translate(0.000000,888.000000) scale(0.100000,-0.100000)"><text x="71188" y="-14488" font-size="2888px" font-family="impact" font-weight="bold" dominant-baseline="center" text-anchor="end">', tokenIdString,
        '</text></g><path d="M3130 5540 l0 -1600 100 0 100 0 0 -185 0 -185 195 0 195 0 0 -85 0 -85 130 0 130 0 0 215 0 215 -195 0 -195 0 0 185 0 185 -100 0 -100 0 0 1340 0 1340 1050 0 1050 0 0 -1340 0 -1340 -100 0 -100 0 0 -185 0 -185 -195 0 -195 0 0 -215 0 -215 130 0 130 0 0 85 0 85 195 0 195 0 0 185 0 185 100 0 100 0 0 1600 0 1600 -1310 0 -1310 0 0 -1600z"/> <path d="M3390 5540 l0 -1340 100 0 100 0 0 -185 0 -185 195 0 195 0 0 -215 0 -215 460 0 460 0 0 215 0 215 195 0 195 0 0 185 0 185 100 0 100 0 0 1340 0 1340 -1050 0 -1050 0 0 -1340z" fill="'
      );
      string memory _last = concatenate(svgBackgroundColor[feature.skinColor], finality[_tokenId] == false ? '<path d="M3750 5770 l0 -120 -120 0 -120 0 0 -120 0 -120 120 0 120 0 0 -240 0 -240 120 0 120 0 0 240 0 240 120 0 120 0 0 120 0 120 -120 0 -120 0 0 120 0 120 -120 0 -120 0 0 -120z M4890 5770 l0 -120 -120 0 -120 0 0 -120 0 -120 120 0 120 0 0 -240 0 -240 120 0 120 0 0 240 0 240 120 0 120 0 0 120 0 120 -120 0 -120 0 0 120 0 120 -120 0 -120 0 0 -120z" fill="' : '<path d="M3730 5790 l0 -120 -120 0 -120 0 0 -140 0 -140 120 0 120 0 0 -240 0 -240 140 0 140 0 0 240 0 240 120 0 120 0 0 140 0 140 -120 0 -120 0 0 120 0 120 -140 0 -140 0 0 -120z m250 -30 l0 -120 120 0 120 0 0 -110 0 -110 -120 0 -120 0 0 -240 0 -240 -110 0 -110 0 0 240 0 240 -120 0 -120 0 0 110 0 110 120 0 120 0 0 120 0 120 110 0 110 0 0 -120z M3790 5730 l0 -120 -120 0 -120 0 0 -80 0 -80 120 0 120 0 0 -240 0 -240 80 0 80 0 0 240 0 240 120 0 120 0 0 80 0 80 -120 0 -120 0 0 120 0 120 -80 0 -80 0 0 -120z m130 -30 l0 -120 120 0 120 0 0 -50 0 -50 -120 0 -120 0 0 -240 0 -240 -50 0 -50 0 0 240 0 240 -120 0 -120 0 0 50 0 50 120 0 120 0 0 120 0 120 50 0 50 0 0 -120z M3850 5670 l0 -120 -120 0 c-113 0 -120 -1 -120 -20 0 -19 7 -20 120 -20 l120 0 0 -240 c0 -233 1 -240 20 -240 19 0 20 7 20 240 l0 240 120 0 c113 0 120 1 120 20 0 19 -7 20 -120 20 l-120 0 0 120 c0 113 -1 120 -20 120 -19 0 -20 -7 -20 -120z M4870 5790 l0 -120 -120 0 -120 0 0 -140 0 -140 120 0 120 0 0 -240 0 -240 140 0 140 0 0 240 0 240 120 0 120 0 0 140 0 140 -120 0 -120 0 0 120 0 120 -140 0 -140 0 0 -120z m250 -30 l0 -120 120 0 120 0 0 -110 0 -110 -120 0 -120 0 0 -240 0 -240 -110 0 -110 0 0 240 0 240 -120 0 -120 0 0 110 0 110 120 0 120 0 0 120 0 120 110 0 110 0 0 -120z M4930 5730 l0 -120 -120 0 -120 0 0 -80 0 -80 120 0 120 0 0 -240 0 -240 80 0 80 0 0 240 0 240 120 0 120 0 0 80 0 80 -120 0 -120 0 0 120 0 120 -80 0 -80 0 0 -120z m130 -30 l0 -120 120 0 120 0 0 -50 0 -50 -120 0 -120 0 0 -240 0 -240 -50 0 -50 0 0 240 0 240 -120 0 -120 0 0 50 0 50 120 0 120 0 0 120 0 120 50 0 50 0 0 -120z M4990 5670 l0 -120 -120 0 c-113 0 -120 -1 -120 -20 0 -19 7 -20 120 -20 l120 0 0 -240 c0 -233 1 -240 20 -240 19 0 20 7 20 240 l0 240 120 0 c113 0 120 1 120 20 0 19 -7 20 -120 20 l-120 0 0 120 c0 113 -1 120 -20 120 -19 0 -20 -7 -20 -120z" fill="',
      svgBackgroundColor[feature.eyesColor], features2.readMouth(feature.mouthStyle), svgBackgroundColor[feature.mouthColor], features1.readMisc(feature.miscStyle1), svgBackgroundColor[feature.miscStyle1Color],  features1.readMisc(feature.miscStyle2),svgBackgroundColor[feature.miscStyle2Color]);
      string memory imageURI = string(abi.encodePacked("data:image/svg+xml;base64, ", Base64.encode(bytes(string(abi.encodePacked(_first, _last,features3.readHair(feature.hairStyle), svgBackgroundColor[feature.hairColor],'</g></svg>'))))));
      string memory finality_ = finality[_tokenId] == false ? 'false' : 'true';

      return string(
        abi.encodePacked(
          "data:application/json;base64,",
          Base64.encode(
            bytes(
              abi.encodePacked(
                '{"name":"',
                "METAKAYS-", tokenIdString,
                '", "attributes":[{"trait_type" : "Finality", "value" : "', finality_ ,'"}], "image":"',imageURI,'"}'
              )
            )
          )
        )
      );
    }

    function concatenate(string memory _one, string memory _two, string memory _three, string memory _four, string memory _five, string memory _six, string memory _seven, string memory _eight, string memory _nine) internal pure returns (string memory) {
      return string(abi.encodePacked(_one, _two, _three, _four, _five, _six, _seven, _eight, _nine));
    }

    function customShirtCheck(string memory svg) internal pure returns (bool) {
      bytes memory b = bytes(svg);
      if (b.length > 8) return false;
      for (uint256 i=0; i<b.length; i++){
        bytes1 char = b[i];
        if (!(char > 0x40 && char < 0x5B)) {
          return false;
        }
      }
      return true;
    }

    function toString(uint256 value) internal pure returns (string memory) {
      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);
    }

    function getOwnershipData(uint256 tokenId) external view returns (TokenOwnership memory) {
      return ownershipOf(tokenId);
    }

    function setOwnersExplicit(uint256 quantity) external onlyOwner {
      _setOwnersExplicit(quantity);
    }

}

// File: base64-sol/base64.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0;

/// @title Base64
/// @author Brecht Devos - <brecht@loopring.org>
/// @notice Provides functions for encoding/decoding base64
library Base64 {
    string internal constant TABLE_ENCODE = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
    bytes  internal constant TABLE_DECODE = hex"0000000000000000000000000000000000000000000000000000000000000000"
                                            hex"00000000000000000000003e0000003f3435363738393a3b3c3d000000000000"
                                            hex"00000102030405060708090a0b0c0d0e0f101112131415161718190000000000"
                                            hex"001a1b1c1d1e1f202122232425262728292a2b2c2d2e2f303132330000000000";

    function encode(bytes memory data) internal pure returns (string memory) {
        if (data.length == 0) return '';

        // load the table into memory
        string memory table = TABLE_ENCODE;

        // 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) {}
            {
                // read 3 bytes
                dataPtr := add(dataPtr, 3)
                let input := mload(dataPtr)

                // write 4 characters
                mstore8(resultPtr, mload(add(tablePtr, and(shr(18, input), 0x3F))))
                resultPtr := add(resultPtr, 1)
                mstore8(resultPtr, mload(add(tablePtr, and(shr(12, input), 0x3F))))
                resultPtr := add(resultPtr, 1)
                mstore8(resultPtr, mload(add(tablePtr, and(shr( 6, input), 0x3F))))
                resultPtr := add(resultPtr, 1)
                mstore8(resultPtr, 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;
    }

    function decode(string memory _data) internal pure returns (bytes memory) {
        bytes memory data = bytes(_data);

        if (data.length == 0) return new bytes(0);
        require(data.length % 4 == 0, "invalid base64 decoder input");

        // load the table into memory
        bytes memory table = TABLE_DECODE;

        // every 4 characters represent 3 bytes
        uint256 decodedLen = (data.length / 4) * 3;

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

        assembly {
            // padding with '='
            let lastBytes := mload(add(data, mload(data)))
            if eq(and(lastBytes, 0xFF), 0x3d) {
                decodedLen := sub(decodedLen, 1)
                if eq(and(lastBytes, 0xFFFF), 0x3d3d) {
                    decodedLen := sub(decodedLen, 1)
                }
            }

            // set the actual output length
            mstore(result, decodedLen)

            // 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, 4 characters at a time
            for {} lt(dataPtr, endPtr) {}
            {
               // read 4 characters
               dataPtr := add(dataPtr, 4)
               let input := mload(dataPtr)

               // write 3 bytes
               let output := add(
                   add(
                       shl(18, and(mload(add(tablePtr, and(shr(24, input), 0xFF))), 0xFF)),
                       shl(12, and(mload(add(tablePtr, and(shr(16, input), 0xFF))), 0xFF))),
                   add(
                       shl( 6, and(mload(add(tablePtr, and(shr( 8, input), 0xFF))), 0xFF)),
                               and(mload(add(tablePtr, and(        input , 0xFF))), 0xFF)
                    )
                )
                mstore(resultPtr, shl(232, output))
                resultPtr := add(resultPtr, 3)
            }
        }

        return result;
    }
}

// File: @openzeppelin/contracts/utils/introspection/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: @openzeppelin/contracts/utils/introspection/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: @openzeppelin/contracts/utils/cryptography/MerkleProof.sol



// SPDX-License-Identifier: MIT

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) {
        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));
            }
        }

        // Check if the computed hash (root) is equal to the provided root
        return computedHash == root;
    }
}

// File: @openzeppelin/contracts/utils/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: @openzeppelin/contracts/utils/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: @openzeppelin/contracts/utils/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: @openzeppelin/contracts/token/ERC721/extensions/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: @openzeppelin/contracts/token/ERC721/extensions/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: @openzeppelin/contracts/token/ERC721/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: @openzeppelin/contracts/token/ERC721/IERC721.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../../utils/introspection/IERC165.sol";

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

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

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

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

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

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

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

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

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

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

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

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

// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../utils/Context.sol";

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

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _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: /Users/kokleongseow/Documents/PROJECTS/METAKAWS-contract/contracts/ERC721.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol";
import "@openzeppelin/contracts/utils/Address.sol";
import "@openzeppelin/contracts/utils/Context.sol";
import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/utils/introspection/ERC165.sol";

/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata and Enumerable extension. Built to optimize for lower gas during batch mints.
 *
 * Assumes serials are sequentially minted starting at 0 (e.g. 0, 1, 2, 3..).
 *
 * Assumes the number of issuable tokens (collection size) is capped and fits in a uint128.
 *
 * Does not support burning tokens to address(0).
 */
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 collectionSize;
  uint256 internal immutable maxBatchSize;

  // Token name
  string private _name;

  // Token symbol
  string private _symbol;

  //DID NOT END UP USING. KEEPING IT HERE FOR SENTIMENTAL + SYMBOLIC REASONS.
  mapping(uint256 => string) private _tokenURIs;

  // 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.
   * `collectionSize_` refers to how many tokens are in the collection.
   */
  constructor(
    string memory name_,
    string memory symbol_,
    uint256 maxBatchSize_,
    uint256 collectionSize_
  ) {
    require(
      collectionSize_ > 0,
      "ERC721: collection must have a nonzero supply"
    );
    require(maxBatchSize_ > 0, "ERC721: max batch size must be nonzero");
    _name = name_;
    _symbol = symbol_;
    maxBatchSize = maxBatchSize_;
    collectionSize = collectionSize_;
  }

  /**
   * @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(collectionSize). 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;
  }

  //DID NOT END UP USING. KEEPING IT HERE FOR SENTIMENTAL + SYMBOLIC REASONS.
  /**
   * @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 _tokenURI = _tokenURIs[tokenId];
    return _tokenURI;
  }

  //DID NOT END UP USING. KEEPING IT HERE FOR SENTIMENTAL + SYMBOLIC REASONS.
  function _setTokenURI(uint256 tokenId, string memory _tokenURI) internal virtual {
      require(
        _exists(tokenId),
        "ERC721URIStorage: URI set of nonexistent token"
      );
      _tokenURIs[tokenId] = _tokenURI;
    }

  /**
   * @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:
   *
   * - there must be `quantity` tokens remaining unminted in the total collection.
   * - `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 > collectionSize - 1) {
      endIndex = collectionSize - 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 {}
}