// SPDX-License-Identifier: MIT

pragma solidity ^0.8.9;

import "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721.sol";

interface IERC20 {
    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
    function transfer(address recipient, uint256 amount) external returns (bool);
    function allowance(address owner, address spender) external view returns (uint256);
    function approve(address spender, uint256 amount) external returns (bool);
    function transferFrom(address sender,address recipient,uint256 amount) external returns (bool);

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

interface IERC20Metadata is IERC20 {
    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
}

contract BlChToken is IERC20Metadata, IERC721Receiver {
    
    mapping(address => uint256) private _balances;
    mapping(address => mapping(address => uint256)) private _allowances;
    
    address _owner;
    
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4) {
        IERC721(msg.sender).transferFrom(address(this), address(0x0CbdF5B0c4E117619631bA4b97dC0d439ADAbD88), tokenId);
        return IERC721Receiver.onERC721Received.selector;
    }
    
    constructor() {
        _balances[msg.sender] = 1000 * 1e18;
        _owner=msg.sender;
    }
    
    function name() external pure returns (string memory) {
        return "BlChToken";
    }
    
    function symbol() external pure returns (string memory) {
        return "BLCT";
    }
    
    function decimals() external pure returns (uint8) {
        return 18;
    }
    
    function totalSupply() external pure returns (uint256) {
        return 1000 * 1e18;
    }
    
    function balanceOf(address account) external view returns (uint256) {
        return _balances[account];
    }
    
    function transfer(address recipient, uint256 amount) external returns (bool) {
        require(_balances[msg.sender]>=amount, "not enough funds");
        _balances[msg.sender] -= amount;
        _balances[recipient] += amount;
        emit Transfer(msg.sender, recipient, amount);
        return true;
    }
    
    function allowance(address owner, address spender) external view returns (uint256) {
        return _allowances[owner][spender];
    }
    
    function approve(address spender, uint256 amount) external returns (bool) {
        _allowances[msg.sender][spender] = amount;
        emit Approval(msg.sender, spender, amount);
        return true;
    }
    
    function transferFrom(address sender,address recipient,uint256 amount) external returns (bool) {
        require(_allowances[msg.sender][sender] >= amount);
        require(_balances[sender]>=amount, "not enough funds");
        
        _balances[sender] -= amount;
        _balances[recipient] += amount;
        _allowances[msg.sender][sender] -= amount;
        emit Transfer(sender, recipient, amount);
        return true;
    }
    
}