// File: Address.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        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");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (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");

        // solhint-disable-next-line avoid-low-level-calls
        (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");

        // solhint-disable-next-line avoid-low-level-calls
        (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");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private 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

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: Context.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

    function _msgData() internal view virtual returns (bytes calldata) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// File: ERC165.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IERC165.sol";

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

// File: ERC721.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IERC721.sol";
import "./IERC721Receiver.sol";
import "./IERC721Metadata.sol";
import "./IERC721Enumerable.sol";
import "./Address.sol";
import "./Context.sol";
import "./Strings.sol";
import "./ERC165.sol";

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

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

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

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

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

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

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

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

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

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

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

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

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

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

    /**
     * @dev Base URI for computing {tokenURI}. Empty by default, can be overriden
     * in child contracts.
     */
    function _baseURI() internal view virtual returns (string memory) {
        return "";
    }

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

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

        _approve(to, tokenId);
    }

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

        return _tokenApprovals[tokenId];
    }

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

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

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

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

        _transfer(from, to, tokenId);
    }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        _beforeTokenTransfer(from, to, tokenId);

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

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

        emit Transfer(from, to, tokenId);
    }

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

    /**
     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
     * The call is not executed if the target address is not a contract.
     *
     * @param from address representing the previous owner of the given token ID
     * @param to target address that will receive the tokens
     * @param tokenId uint256 ID of the token to be transferred
     * @param _data bytes optional data to send along with the call
     * @return bool whether the call correctly returned the expected magic value
     */
    function _checkOnERC721Received(address from, address to, uint256 tokenId, bytes memory _data)
        private returns (bool)
    {
        if (to.isContract()) {
            try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
                return retval == IERC721Receiver(to).onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert("ERC721: transfer to non ERC721Receiver implementer");
                } else {
                    // solhint-disable-next-line no-inline-assembly
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            return true;
        }
    }

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

// File: ERC721Enumerable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

// File: 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: IERC721.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IERC165.sol";

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

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

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

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

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

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

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

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

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

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

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

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

// File: IERC721Enumerable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IERC721.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Enumerable is IERC721 {

    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalSupply() external view returns (uint256);

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

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

// File: IERC721Metadata.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IERC721.sol";

/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Metadata is IERC721 {

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

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

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

// File: 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: Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), 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 {
        emit OwnershipTransferred(_owner, address(0));
        _owner = 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");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// File: Strings.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant alphabet = "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] = alphabet[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }

}

// File: ThisIsNFT.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

//import "./StringUtils.sol";
import "./ERC721.sol";
import "./Ownable.sol";



/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension, but not including the Enumerable extension, which is available separately as
 * {ERC721Enumerable}.
 */
contract ThisIsNFT is  Ownable, ERC721 {
    
    using Strings for uint256;
    using Strings for uint8;

    string public artist = "Eivind Kleiven";
    string public description = "\"This is NFT\" is an onchain project showing what NFT is at its simplest form, a TokenID with transferable ownership in a contract. Anyone can mint for the price of gas and gas price (in gwei) is set as TokenID.";
    
    string[4] private colors = ['ffe94d','a6e276','ff9c92','da95d1'];
    uint8[4][24] private palettes = [[0,1,2,3],[1,0,2,3],[2,0,1,3],[0,2,1,3],[1,2,0,3],[2,1,0,3],[2,1,3,0],[1,2,3,0],[3,2,1,0],[2,3,1,0],[1,3,2,0],[3,1,2,0],[3,0,2,1],[0,3,2,1],[2,3,0,1],[3,2,0,1],[0,2,3,1],[2,0,3,1],[1,0,3,2],[0,1,3,2],[3,1,0,2],[1,3,0,2],[0,3,1,2],[3,0,1,2]];

    
    string private _pBaseURI;
    bool private _tokenURIAsJson = false;
    
    /**
     * Mapping from tokenId to array where first element is index of palette and second element index of pattern
     */
    mapping(uint256 => uint8) public tokenProperties;

    
    /**
    * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
    */
    constructor () ERC721("This is NFT", "YESITIS") {
        
    }
    
    function color(uint256 tokenId, uint256 index) public view returns (string memory){
        return colors[palettes[tokenProperties[tokenId]][index]];
    }
  

    function getRandomPaletteIndex(uint256 tokenId) internal view returns (uint8) {
       
        uint8 index = uint8(uint(keccak256(abi.encodePacked(block.timestamp, msg.sender, tokenId)))%100);
        
        if(index >= 40){
            return (index-40)/10+18;
        }
        else if(index >=20){
            return (index-20)/5+14;
        }else if(index >=8){
            return (index-8)/2+8;
        }
            
        return index;
    }
    
    function setBaseURI(string memory baseURI) onlyOwner public {
        _pBaseURI = baseURI;
    }
    
    
    function returnJsonFromTokenURI(bool yesorno) onlyOwner public {
        _tokenURIAsJson = yesorno;
    }
    
    function mint() public {
        uint tokenId = tx.gasprice/1000000000;
        _mint(_msgSender(), tokenId);
        tokenProperties[tokenId] = getRandomPaletteIndex(tokenId);
    }
    
    
    function svg(uint256 tokenId) public view returns (string memory) {
        
        string memory part1 = string(abi.encodePacked("<svg version='1.1' xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' viewBox='0 0 900 900' style='background-color:#",color(tokenId,0),";fill:#",color(tokenId,1),";' font-family='Arial' font-size='30'><text x='76' y='280' fill='#",color(tokenId,2),"' font-weight='bold' font-size='130'>THIS IS NFT</text><text transform='matrix(1 0 0 1 100 400)'><tspan x='0' y='0' font-weight='bold' >Account</tspan><tspan x='0' y='36'>",toAsciiString(ownerOf(tokenId)),"</tspan><tspan x='0' y='144' font-weight='bold'>Is holder of TokenId</tspan><a href='data:text/html,%3C%21DOCTYPE%20html>%3Chtml%20lang%3D%22en%22>%3Chead>%3Ctitle>This%20is%20NFT%20%23",tokenId.toString(),"%3C%2Ftitle>%3Cmeta%20charset%3D%22UTF-8%22>%3Cmeta%20name%3D%22viewport%22%20content%3D%22width%3Ddevice-width%2C%20initial-scale%3D1.0%22>%3Cmeta%20name%3D%22apple-mobile-web-app-capable%22%20content%3D%22yes%22>%3Cstyle>%2A{touch-action%3Anone%3Buser-select%3Anone%3B-webkit-user-select%3Anone%3B-ms-user-select%3Anone%3B-moz-user-select%3Anone%3Bbox-sizing%3Aborder-box}img{pointer-events%3Anone}body{margin%3A0%3Bpadding%3A0%3Bmin-height%3A100vh%3Boverflow%3Ahidden%3Bbackground-color%3A%23202020}%23content{min-height%3A100vh}%23wrapper{min-height%3A100vh}%23scene{--size%3A0px%3B--scale%3A0.65%3Bheight%3Avar%28--size%29%3Bwidth%3Avar%28--size%29%3Bperspective%3A3000px}%23cube{height%3A100%25%3Bposition%3Arelative%3B--rotation-x%3A-40deg%3B--rotation-y%3A45deg%3Btransform-style%3Apreserve-3d%3Btransform%3AtranslateZ%28calc%28-1%2A%28var%28--size%29%2F2%29%29%29%20scale3d%28var%28--scale%29%2C%20var%28--scale%29%2C%20var%28--scale%29%29%20rotateX%28var%28--rotation-x%29%29%20rotateY%28var%28--rotation-y%29%29}.face{display%3Aflex%3Bjustify-content%3Aspace-around%3Balign-items%3Acenter%3Bposition%3Aabsolute%3Bwidth%3Avar%28--size%29%3Bheight%3Avar%28--size%29}.front{transform%3ArotateY%280deg%29%20translateZ%28calc%28var%28--size%29%2F2%29%29}.right{transform%3ArotateY%2890deg%29%20translateZ%28calc%28var%28--size%29%2F2%29%29}.back{transform%3ArotateY%28180deg%29%20translateZ%28calc%28var%28--size%29%2F2%29%29}.left{transform%3ArotateY%28-90deg%29%20translateZ%28calc%28var%28--size%29%2F2%29%29}.top{transform%3ArotateX%2890deg%29%20translateZ%28calc%28var%28--size%29%2F2%29%29}.bottom{transform%3ArotateX%28-90deg%29%20translateZ%28calc%28var%28--size%29%2F2%29%29}%40keyframes%20spin{0%25{transform%3AtranslateZ%28calc%28-1%2Avar%28--size%29%2F2%29%29%20scale3d%28var%28--scale%29%2C%20var%28--scale%29%2C%20var%28--scale%29%29%20rotateX%28var%28--rotation-x%29%29%20rotateY%28calc%28var%28--rotation-y%29%29%29}100%25{transform%3AtranslateZ%28calc%28-1%2Avar%28--size%29%2F2%29%29%20scale3d%28var%28--scale%29%2C%20var%28--scale%29%2C%20var%28--scale%29%29%20rotateX%28var%28--rotation-x%29%29%20rotateY%28calc%28var%28--rotation-y%29%20%2B%20360deg%29%29}}%3C%2Fstyle>%20%3Cscript>let%20svg%2Cwrapper%3Ddocument.getElementById%28%22wrapper%22%29%2Cscene%3Ddocument.getElementById%28%22scene%22%29%2Ccube%3Ddocument.getElementById%28%22cube%22%29%2Cp1ScreenX%3D-1%2Cp1ScreenY%3D-1%2Cp1PointerId%3D-1%2Cp2ScreenX%3D-1%2Cp2ScreenY%3D-1%2Cp2PointerId%3D-1%2CprevDiff%3D-1%3Bfunction%20getRotationYFrom3DMatrix%28e%29{var%20t%3DparseFloat%28getComputedStyle%28cube%29.getPropertyValue%28%22--scale%22%29%29%2Cn%3D%28n%3D%28n%3De.split%28%22%28%22%29%5B1%5D%29.split%28%22%29%22%29%5B0%5D%29.split%28%22%2C%22%29%2Cr%3DMath.sign%28n%5B0%5D%29%2Co%3DMath.abs%28n%5B0%5D%2Ft%29%2Ce%3Dr%2A%28o-Math.floor%28o%29%29%2Ct%3Dn%5B1%5D%2Co%3Dn%5B2%5D%2Cn%3Dn%5B3%5D%2Ce%3DMath.round%28Math.acos%28e%29%2A%28180%2FMath.PI%29%29%2Ct%3DMath.round%28Math.asin%28t%29%2A%28180%2FMath.PI%29%29%2Co%3DMath.round%28-1%2AMath.asin%28o%29%2A%28180%2FMath.PI%29%29%2Cr%3D%28Math.round%28Math.acos%28n%29%2A%28180%2FMath.PI%29%29%2C1%29%3Bt%3C0%3FMath.sign%28t%29%3D%3DMath.sign%28o%29%26%26%28r%3D-1%29%3A0%3Ct%26%26Math.sign%28t%29%21%3DMath.sign%28o%29%26%26%28r%3D-1%29%3Bo%3DparseInt%28getComputedStyle%28cube%29.getPropertyValue%28%22--rotation-x%22%29.substr%280%2CgetComputedStyle%28cube%29.getPropertyValue%28%22--rotation-x%22%29.indexOf%28%22deg%22%29%29%29%3Breturn%2090%3C%3DMath.abs%28o%29%26%26Math.abs%28o%29%3C270%26%26%28r%2A%3D-1%29%2Cr%2Ae}function%20setSize%28%29{stopSpin%28%29%2Cscene.style.setProperty%28%22--size%22%2C%220px%22%29%2Cwrapper.style.marginRight%3D%220px%22%2Cwrapper.style.marginLeft%3D%220px%22%3Bvar%20e%3Dwrapper.offsetHeight%2Ct%3Dwrapper.offsetWidth%2B2%2Awrapper.offsetLeft%3Blet%20n%3D0%2Cr%3Dt%3Be%3Ct%26%26%28n%3Dt-e%2Cr%3De%29%2Cwrapper.style.marginRight%3DMath.ceil%28n%2F2%29%2B%22px%22%2Cwrapper.style.marginLeft%3DMath.floor%28n%2F2%29%2B%22px%22%2Cscene.style.setProperty%28%22--size%22%2Cr%2B%22px%22%29%2CstartSpin%28%29}function%20zoom%28e%29{stopSpin%28%29%2Cscene.style.setProperty%28%22--scale%22%2CMath.max%28%2BMath.sign%28e%29%2F80%2BparseFloat%28getComputedStyle%28scene%29.getPropertyValue%28%22--scale%22%29%29%2C.01%29%29}function%20pointerdown_handler%28e%29{stopSpin%28%29%2C-1%3D%3Dp1PointerId%3F%28p1PointerId%3De.pointerId%2Cp1ScreenX%3De.screenX%2Cp1ScreenY%3De.screenY%29%3A-1%3D%3Dp2PointerId%26%26%28p2PointerId%3De.pointerId%2Cp2ScreenX%3De.screenX%2Cp2ScreenY%3De.screenY%29}function%20pointerup_handler%28e%2Ct%29{startSpin%28%29%2Cp1PointerId%3D-1%2Cp1ScreenX%3D-1%2Cp1ScreenY%3D-1%2Cp2PointerId%3D-1%2Cp2ScreenX%3D-1%2C%28p2ScreenY%3D-1%29%21%3Dp1PointerId%26%26-1%21%3Dp2PointerId||%28prevDiff%3D-1%29}function%20pointermove_handler%28n%29{if%28n.preventDefault%28%29%2C-1%21%3Dp1PointerId%29{let%20e%3D0%2Ct%3D0%3Bn.pointerId%3D%3Dp1PointerId%3F%28e%3Dn.screenX-p1ScreenX%2Ct%3Dn.screenY-p1ScreenY%2Cp1ScreenX%3Dn.screenX%2Cp1ScreenY%3Dn.screenY%29%3An.pointerId%3D%3Dp2PointerId%26%26%28p2ScreenX%3Dn.screenX%2Cp2ScreenY%3Dn.screenY%29%2C-1%21%3Dp1PointerId%26%26-1%3D%3Dp2PointerId%3Frotate%28e%2Ct%29%3A-1%21%3Dp1PointerId%26%26-1%21%3Dp2PointerId%26%26%28n%3DMath.sqrt%28Math.pow%28p1ScreenX-p2ScreenX%2C2%29%2BMath.pow%28p1ScreenY-p2ScreenY%2C2%29%29%2C0%3CprevDiff%26%26zoom%28n-prevDiff%29%2CprevDiff%3Dn%29}}function%20rotate%28e%2Ct%29{t%3D%28parseInt%28getComputedStyle%28cube%29.getPropertyValue%28%22--rotation-x%22%29.substr%280%2CgetComputedStyle%28cube%29.getPropertyValue%28%22--rotation-x%22%29.indexOf%28%22deg%22%29%29%29%2B-1%2At%29%25360%2B%22deg%22%2Ce%3DparseInt%28getComputedStyle%28cube%29.getPropertyValue%28%22--rotation-y%22%29.substr%280%2CgetComputedStyle%28cube%29.getPropertyValue%28%22--rotation-y%22%29.indexOf%28%22deg%22%29%29%29%2Be%2B%22deg%22%3Bcube.style.setProperty%28%22--rotation-x%22%2Ct%29%2Ccube.style.setProperty%28%22--rotation-y%22%2Ce%29}function%20stopSpin%28%29{var%20e%3Dwindow.getComputedStyle%28cube%29.getPropertyValue%28%22transform%22%29%3Bcube.style.animation%3D%22none%22%3Be%3DgetRotationYFrom3DMatrix%28e%29%3Bcube.style.setProperty%28%22--rotation-y%22%2Ce%2B%22deg%22%29}function%20startSpin%28%29{cube.style.animation%3D%22spin%2020s%20linear%20infinite%22}window.addEventListener%28%22DOMContentLoaded%22%2C%28%29%3D>{wrapper%3Ddocument.getElementById%28%22wrapper%22%29%2Cscene%3Ddocument.getElementById%28%22scene%22%29%2Ccube%3Ddocument.getElementById%28%22cube%22%29%2Csvg%3Ddocument.getElementsByTagName%28%22svg%22%29%5B0%5D%2Ccube.children%5B1%5D.appendChild%28svg.cloneNode%28%210%29%29%2Ccube.children%5B2%5D.appendChild%28svg.cloneNode%28%210%29%29%2Ccube.children%5B3%5D.appendChild%28svg.cloneNode%28%210%29%29%2Ccube.children%5B4%5D.appendChild%28svg.cloneNode%28%210%29%29%2Ccube.children%5B5%5D.appendChild%28svg.cloneNode%28%210%29%29%2Cscene.addEventListener%28%22pointerup%22%2Cpointerup_handler%29%2Cscene.addEventListener%28%22pointermove%22%2Cpointermove_handler%29%2Cscene.addEventListener%28%22pointerdown%22%2Cpointerdown_handler%29%2Cscene.addEventListener%28%22pointerleave%22%2Cpointerup_handler%29%2Cscene.addEventListener%28%22pointercancel%22%2Cpointerup_handler%29%2Cscene.addEventListener%28%22wheel%22%2Ce%3D>{zoom%28-1%2Ae.deltaY%29}%29%2CsetSize%28%29%2Cvoid%200%21%3D%3Dwindow.onresize%3Fwindow.onresize%3DsetSize%3Avoid%200%21%3D%3Dwindow.onorientationchange%26%26%28window.onorientationchange%3DsetSize%29}%29%3B%3C%2Fscript>%20%3C%2Fhead>%3Cbody>%3Cdiv%20id%3D%22content%22>%3Cdiv%20id%3D%22wrapper%22>%3Cdiv%20id%3D%22scene%22>%3Cdiv%20id%3D%22cube%22%20class%3D%22cube%22>%3Cdiv%20class%3D%22face%20front%22>%20%3Csvg%20version%3D%221.1%22%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20xmlns%3Axlink%3D%22http%3A%2F%2Fwww.w3.org%2F1999%2Fxlink%22%20viewBox%3D%220%200%20900%20900%22%20style%3D%22background-color%3A%23",color(tokenId,0),"%3Bfill%3A%"));
        string memory part2 = string(abi.encodePacked("23",color(tokenId,1),"%3B%22%20font-family%3D%22Arial%22%20font-size%3D%2230%22>%20%3Ctext%20x%3D%2276%22%20y%3D%22280%22%20fill%3D%22%23",color(tokenId,2),"%22%20font-weight%3D%22bold%22%20font-size%3D%22130%22>THIS%20IS%20NFT%3C%2Ftext>%20%3Ctext%20transform%3D%22matrix%281%200%200%201%20100%20400%29%22>%20%3Ctspan%20x%3D%220%22%20y%3D%220%22%20font-weight%3D%22bold%22%20>Account%3C%2Ftspan>%20%3Ctspan%20x%3D%220%22%20y%3D%2236%22>",toAsciiString(ownerOf(tokenId)),"%3C%2Ftspan>%20%3Ctspan%20x%3D%220%22%20y%3D%22144%22%20font-weight%3D%22bold%22>Is%20holder%20of%20TokenId%3C%2Ftspan>%20%3Ctspan%20x%3D%220%22%20y%3D%22180%22>",tokenId.toString(),"%3C%2Ftspan>%20%3Ctspan%20x%3D%220%22%20y%3D%22288%22%20font-weight%3D%22bold%22>In%20contract%3C%2Ftspan>%20%3Ctspan%20x%3D%220%22%20y%3D%22324%22>",toAsciiString(address(this)),"%3C%2Ftspan>%20%3C%2Ftext>%20%3Ccircle%20cx%3D%22425%22%20cy%3D%22150%22%20r%3D%2220%22%20fill%3D%22%23",color(tokenId,3),"%22>%3C%2Fcircle>%20%3C%2Fsvg>%3C%2Fdiv>%3Cdiv%20class%3D%22face%20back%22>%3C%2Fdiv>%3Cdiv%20class%3D%22face%20right%22>%3C%2Fdiv>%3Cdiv%20class%3D%22face%20left%22>%3C%2Fdiv>%3Cdiv%20class%3D%22face%20top%22>%3C%2Fdiv>%3Cdiv%20class%3D%22face%20bottom%22>%3C%2Fdiv>%3C%2Fdiv>%3C%2Fdiv>%3C%2Fdiv>%3C%2Fdiv>%3C%2Fbody>%3C%2Fhtml>'><tspan x='0' y"));
        string memory part3 = string(abi.encodePacked("='180' fill='#",color(tokenId,1),"'>",tokenId.toString(),"</tspan></a><tspan x='0' y='288' font-weight='bold'>In contract</tspan><tspan x='0' y='324'>",toAsciiString(address(this)),"</tspan></text><circle cx='425' cy='150' r='20' fill='#",color(tokenId,3),"'></circle></svg>"));
       
        return string(abi.encodePacked(part1,part2,part3));
        
    }
    
    function metadata(uint256 tokenId) public view returns (string memory) {
        return string(abi.encodePacked("{\"name\":\"This is NFT #",tokenId.toString(),"\",\"createdBy\":\"Eivind Kleiven\",\"yearCreated\":\"2021\",\"description\": \"Still don't know what the hells a NFT?\",\"image_data\":\"",svg(tokenId),"\",\"attributes\":[{\"trait_type\":\"Palette\",\"value\":\"",tokenProperties[tokenId].toString(),"\"}]}"));
    }

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId) public view override returns (string memory) {
        require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
        
        if(_tokenURIAsJson){
            return metadata(tokenId);
        }
        
        string memory part1 = string(abi.encodePacked(_pBaseURI,"?t=",tokenId.toString(),"&a=",toAsciiString(ownerOf(tokenId)),"&c=",toAsciiString(address(this))));
        string memory part2 = string(abi.encodePacked("&p=",tokenProperties[tokenId].toString(),"&c0=",color(tokenId,0),"&c1=",color(tokenId,1),"&c2=",color(tokenId,2),"&c3=",color(tokenId,3)));
        
        return string(abi.encodePacked(part1,part2));
        
    }
    
    
    
    function toAsciiString(address x) internal pure returns (string memory) {
        bytes memory s = new bytes(40);
        for (uint i = 0; i < 20; i++) {
            bytes1 b = bytes1(uint8(uint(uint160(x)) / (2**(8*(19 - i)))));
            bytes1 hi = bytes1(uint8(b) / 16);
            bytes1 lo = bytes1(uint8(b) - 16 * uint8(hi));
            s[2*i] = char(hi);
            s[2*i+1] = char(lo);            
        }
        return string(abi.encodePacked("0x",s));
    }

    function char(bytes1 b) internal pure returns (bytes1 c) {
        if (uint8(b) < 10) return bytes1(uint8(b) + 0x30);
        else return bytes1(uint8(b) + 0x57);
    }
    
    /**
     * @dev Burns `tokenId`. See {ERC721-_burn}.
     *
     * Requirements:
     *
     * - The caller must own `tokenId` or be an approved operator.
     */
    function burn(uint256 tokenId) public virtual {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721Burnable: caller is not owner nor approved");
        _burn(tokenId);
    }
    
}