// SPDX-License-Identifier: MIT

// Copyright (c) 2018 The VeChainThor developers

// Distributed under the GNU Lesser General Public License v3.0 software license, see the accompanying
// file LICENSE or <https://www.gnu.org/licenses/lgpl-3.0.html>

pragma solidity 0.8.20;


/**
 * @title VIP181 Non-Fungible Token Standard basic interface
 */
abstract contract IVIP181Basic {

    bytes4 internal constant InterfaceId_VIP181 = 0x291a6960;
    /*
    * 0x291a6960 ===
    *   bytes4(keccak256('totalSupply()')) ^
    *   bytes4(keccak256('balanceOf(address)')) ^
    *   bytes4(keccak256('ownerOf(uint256)')) ^
    *   bytes4(keccak256('approve(address,uint256)')) ^
    *   bytes4(keccak256('getApproved(uint256)')) ^
    *   bytes4(keccak256('transferFrom(address,address,uint256)'))
    */

    bytes4 internal constant InterfaceId_VIP181Metadata = 0x5b5e139f;
    /**
    * 0x5b5e139f ===
    *   bytes4(keccak256('name()')) ^
    *   bytes4(keccak256('symbol()')) ^
    *   bytes4(keccak256('tokenURI(uint256)'))
    */


    /// @dev This emits when an operator is enabled or disabled for an owner.
    ///  The operator can manage all NFTs of the owner.
    event ApprovalForAll(address indexed _owner, address indexed _operator, bool _approved);

    /// @notice Count all NFTs assigned to an owner
    /// @dev NFTs assigned to the zero address are considered invalid, and this
    ///  function throws for queries about the zero address.
    /// @param _owner An address for whom to query the balance
    /// @return The number of NFTs owned by `_owner`, possibly zero
    function balanceOf(address _owner) public virtual view returns (uint256);

    /// @notice Find the owner of an NFT
    /// @dev NFTs assigned to zero address are considered invalid, and queries
    ///  about them do throw.
    /// @param _tokenId The identifier for an NFT
    /// @return The address of the owner of the NFT
    function ownerOf(uint256 _tokenId) public virtual view returns (address);


    /// @notice Set or reaffirm the approved address for an NFT
    /// @dev The zero address indicates there is no approved address.
    /// @dev Throws unless `msg.sender` is the current NFT owner, or an authorized
    ///  operator of the current owner.
    /// @param _to The new approved NFT controller
    /// @param _tokenId The NFT to approve
    function approve(address _to, uint256 _tokenId) public virtual;

    /// @notice Get the approved address for a single NFT
    /// @dev Throws if `_tokenId` is not a valid NFT
    /// @param _tokenId The NFT to find the approved address for
    /// @return The approved address for this NFT, or the zero address if there is none
    function getApproved(uint256 _tokenId) public virtual view returns (address);

    /// @notice Transfer ownership of an NFT -- THE CALLER IS RESPONSIBLE
    ///  TO CONFIRM THAT `_to` IS CAPABLE OF RECEIVING NFTS OR ELSE
    ///  THEY MAY BE PERMANENTLY LOST
    /// @dev Throws unless `msg.sender` is the current owner, an authorized
    ///  operator, or the approved address for this NFT. Throws if `_from` is
    ///  not the current owner. Throws if `_to` is the zero address. Throws if
    ///  `_tokenId` is not a valid NFT.
    /// @param _from The current owner of the NFT
    /// @param _to The new owner
    /// @param _tokenId The NFT to transfer
    function transferFrom(address _from, address _to, uint256 _tokenId) public virtual;

    
}