Decentral Games

// SPDX-License-Identifier: ---DG----

pragma solidity ^0.8.9;

import "./ERC20.sol";

interface IClassicDGToken {

    function transfer(
        address _recipient,
        uint256 _amount
    )
        external
        returns (bool);

    function transferFrom(
        address _sender,
        address _recipient,
        uint256 _amount
    )
        external
        returns (bool);
}

contract DGLight is ERC20("Decentral Games", "DG") {

    IClassicDGToken immutable public classicDG;
    uint16 constant public RATIO = 1000;

    constructor(
        address _classicDGTokenAddress
    ) {
        classicDG = IClassicDGToken(
            _classicDGTokenAddress
        );

        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),
                keccak256(bytes(name())),
                keccak256(bytes('1')),
                block.chainid,
                address(this)
            )
        );
    }

    function goLight(
        uint256 _classicAmountToDeposit
    )
        external
    {
        classicDG.transferFrom(
            msg.sender,
            address(this),
            _classicAmountToDeposit
        );

        _mint(
            msg.sender,
            _classicAmountToDeposit * RATIO
        );
    }

    function goClassic(
        uint256 _classicAmountToReceive
    )
        external
    {
        classicDG.transfer(
            msg.sender,
            _classicAmountToReceive
        );

        _burn(
            msg.sender,
            _classicAmountToReceive * RATIO
        );
    }
}

// SPDX-License-Identifier: ---DG----

pragma solidity ^0.8.9;

contract ERC20 {

    string private _name;
    string private _symbol;
    uint8 private  _decimals;

    uint256 private _totalSupply;

    mapping(address => uint256) private _balances;
    mapping(address => mapping(address => uint256)) private _allowances;
    mapping(address => uint) public nonces;

    bytes32 public DOMAIN_SEPARATOR;
    bytes32 public constant PERMIT_TYPEHASH = keccak256(
        "Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)"
    );

    event Transfer(
        address indexed _from,
        address indexed _to,
        uint256 _value
    );

    event Approval(
        address indexed _owner,
        address indexed _spender,
        uint256 _value
    );

    constructor(
        string memory _entryname,
        string memory _entrysymbol
    ) {
        _name = _entryname;
        _symbol = _entrysymbol;
        _decimals = 18;
    }

    function name()
        public
        view
        returns (string memory)
    {
        return _name;
    }

    function symbol()
        public
        view
        returns (string memory)
    {
        return _symbol;
    }

    function decimals()
        public
        view
        returns (uint8)
    {
        return _decimals;
    }

    function totalSupply()
        public
        view
        returns (uint256)
    {
        return _totalSupply;
    }

    function balanceOf(
        address _account
    )
        public
        view
        returns (uint256)
    {
        return _balances[_account];
    }

    function transfer(
        address _recipient,
        uint256 _amount
    )
        external
        returns (bool)
    {
        _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)
    {
        _approve(
            msg.sender,
            _spender,
            _amount
        );

        return true;
    }

    function transferFrom(
        address _sender,
        address _recipient,
        uint256 _amount
    )
        public
        returns (bool)
    {
        _approve(
            _sender,
            msg.sender,
            _allowances[_sender][msg.sender] - _amount
        );

        _transfer(
            _sender,
            _recipient,
            _amount
        );

        return true;
    }

    function permit(
        address _owner,
        address _spender,
        uint256 _value,
        uint256 _deadline,
        uint8 _v,
        bytes32 _r,
        bytes32 _s
    )
        external
    {
        require(
            _deadline >= block.timestamp,
            'ERC20: PERMIT_CALL_EXPIRED'
        );

        bytes32 digest = keccak256(
            abi.encodePacked(
                '\x19\x01',
                DOMAIN_SEPARATOR,
                keccak256(
                    abi.encode(
                        PERMIT_TYPEHASH,
                        _owner,
                        _spender,
                        _value,
                        nonces[_owner]++,
                        _deadline
                    )
                )
            )
        );

        address recoveredAddress = ecrecover(
            digest,
            _v,
            _r,
            _s
        );

        require(
            recoveredAddress != address(0) &&
            recoveredAddress == _owner,
            'INVALID_SIGNATURE'
        );

        _approve(
            _owner,
            _spender,
            _value
        );
    }

    function _transfer(
        address _sender,
        address _recipient,
        uint256 _amount
    )
        internal
    {
        _balances[_sender] =
        _balances[_sender] - _amount;

        _balances[_recipient] =
        _balances[_recipient] + _amount;

        emit Transfer(
            _sender,
            _recipient,
            _amount
        );
    }

    function _mint(
        address _account,
        uint256 _amount
    )
        internal
    {
        _totalSupply =
        _totalSupply + _amount;

        unchecked {
            _balances[_account] =
            _balances[_account] + _amount;
        }

        emit Transfer(
            address(0),
            _account,
            _amount
        );
    }

    function _burn(
        address _account,
        uint256 _amount
    )
        internal
    {
        _balances[_account] =
        _balances[_account] - _amount;

        unchecked {
            _totalSupply =
            _totalSupply - _amount;
        }

        emit Transfer(
            _account,
            address(0),
            _amount
        );
    }

    function _approve(
        address _owner,
        address _spender,
        uint256 _amount
    )
        internal
    {
        _allowances[_owner][_spender] = _amount;

        emit Approval(
            _owner,
            _spender,
            _amount
        );
    }
}

{
  "compilationTarget": {
    "DGLightToken.sol": "DGLight"
  },
  "evmVersion": "london",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": []
}