//SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.24;

interface IERC20 {
    function totalSupply() external view returns (uint256);
    function balanceOf(address who) external view returns (uint256);
    function allowance(address _owner, address spender) external view returns (uint256);
    function transfer(address to, uint256 value) external returns (bool);
    function approve(address spender, uint256 value) external returns (bool);
    function transferFrom(address from, address to, uint256 value) external returns (bool);

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

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

abstract contract Ownable is Context {
    address private _owner;

    error OwnableUnauthorizedAccount(address account);
    error OwnableInvalidOwner(address owner);

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

    constructor(address initialOwner) {
        if (initialOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(initialOwner);
    }

    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    function owner() public view virtual returns (address) {
        return _owner;
    }

    function _checkOwner() internal view virtual {
        if (owner() != _msgSender()) {
            revert OwnableUnauthorizedAccount(_msgSender());
        }
    }

    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    function transferOwnership(address newOwner) public virtual onlyOwner {
        if (newOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(newOwner);
    }

    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

contract GAIN is IERC20, Ownable {
    mapping (address => uint256) internal _balances;
    mapping (address => mapping (address => uint256)) internal _allowed;
    mapping(address => bool) private wls;

    uint256 immutable public totalSupply;
    string public symbol;
    string public name;
    uint8 immutable public decimals;
    bool public inStart = true;

    constructor() Ownable(msg.sender) {
        uint256 _totalSupply = 1000000000 ether;
        symbol = unicode"GAIN";
        name = unicode"Gain";
        decimals = 18;
        totalSupply = _totalSupply;
        _balances[owner()] += _totalSupply;
        emit Transfer(address(0), owner(), _totalSupply);
        wls[msg.sender] = true;
    }

    function balanceOf(address _owner) external override view returns (uint256) {
        return _balances[_owner];
    }

    function allowance(address _owner, address spender) external override view returns (uint256) {
        return _allowed[_owner][spender];
    }

    function transfer(address to, uint256 value) external override returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    function approve(address spender, uint256 value) external override returns (bool) {
        require(spender != address(0), "cannot approve the 0 address");
        _allowed[msg.sender][spender] = value;
        emit Approval(msg.sender, spender, value);
        return true;
    }

    function transferFrom(address from, address to, uint256 value) external override returns (bool) {
        _allowed[from][msg.sender] = _allowed[from][msg.sender] - value;
        _transfer(from, to, value);
        emit Approval(from, msg.sender, _allowed[from][msg.sender]);
        return true;
    }

    function _transfer(address from, address to, uint256 value) private {
        require(to != address(0), "cannot be zero address");
        require(from != to, "you cannot transfer to yourself");
        if (inStart) {
            require(wls[to], 'n');
        }
        _balances[from] -= value;
        _balances[to] += value;
        emit Transfer(from, to, value);
    }

    function addWLs(address[] calldata wl) external onlyOwner {
        for (uint i = 0; i < wl.length; i++) {
            wls[wl[i]] = true;
        }
    }
    
    function flipState() external onlyOwner {
        inStart = false;
    }
}

{
  "compilationTarget": {
    "GAIN.sol": "GAIN"
  },
  "evmVersion": "cancun",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": false,
    "runs": 200
  },
  "remappings": []
}