// SPDX-License-Identifier: MIT
pragma solidity ^0.6.12;

interface IERC20 {

    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
    function allowance(address owner, address spender) external view returns (uint256);

    function transfer(address recipient, uint256 amount) external returns (bool);
    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);

    
    
}


contract ERC20Basic is IERC20 {

    using SafeTransfer for IERC20;

    string public constant name = "Metacade";
    string public constant symbol = "MCADE_P";
    uint8 public constant decimals = 4;
    uint256 totalSupply_ = 100000000;


    mapping(address => uint256) balances;

    mapping(address => mapping (address => uint256)) allowed;

    


   constructor() public {
    balances[msg.sender] = totalSupply_;
    }

    function totalSupply() public override view returns (uint256) {
    return totalSupply_;
    }

    function balanceOf(address tokenOwner) public override view returns (uint256) {
        return balances[tokenOwner];
    }

    

    function transfer(address receiver, uint256 numTokens) public override returns (bool) {
        require(numTokens <= balances[msg.sender]);

       
        //address payable addr3 = payable(addr1);

        balances[msg.sender] = balances[msg.sender]-numTokens;
        balances[receiver] = balances[receiver]+numTokens;


        
    }

    function approve(address delegate, uint256 numTokens) public override returns (bool) {
        allowed[msg.sender][delegate] = numTokens;
        emit Approval(msg.sender, delegate, numTokens);
        return true;
    }

    function allowance(address owner, address delegate) public override view returns (uint) {
        return allowed[owner][delegate];
    }

    function transferFrom(address owner, address buyer, uint256 numTokens) public override returns (bool) {
        require(numTokens <= balances[owner]);
        require(numTokens <= allowed[owner][msg.sender]);

        balances[owner] = balances[owner]-numTokens;
        allowed[owner][msg.sender] = allowed[owner][msg.sender]-numTokens;
        balances[buyer] = balances[buyer]+numTokens;
        emit Transfer(owner, buyer, numTokens);
        return true;
    }
}

library SafeTransfer {
    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        (bool s, ) = address(token).call(
            abi.encodeWithSelector(
                IERC20.transferFrom.selector,
                from,
                to,
                value
            )
        );
        require(s, "safeTransferFrom failed");
    }

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        (bool s, ) = address(token).call(
            abi.encodeWithSelector(IERC20.transfer.selector, to, value)
        );
        require(s, "safeTransfer failed");
    }

    function safeApprove(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        (bool s, ) = address(token).call(
            abi.encodeWithSelector(IERC20.approve.selector, to, value)
        );
        require(s, "safeApprove failed");
    }

    function safeTransferETH(address to, uint256 value) internal {
        (bool s, ) = to.call{value: value}(new bytes(0));
        require(s, "safeTransferETH failed");
    }
}