DexFactory.sol

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.13;

import "../Ethernaut/Level.sol";
import "./Dex.sol";
import "openzeppelin/token/ERC20/ERC20.sol";

contract DexFactory is Level {
    function createInstance(address _player) public payable override returns (address) {
        Dex instance = new Dex();
        address instanceAddress = address(instance);

        SwappableToken tokenInstance = new SwappableToken(
            instanceAddress,
            "Token 1",
            "TKN1",
            110
        );
        SwappableToken tokenInstanceTwo = new SwappableToken(
            instanceAddress,
            "Token 2",
            "TKN2",
            110
        );

        address tokenInstanceAddress = address(tokenInstance);
        address tokenInstanceTwoAddress = address(tokenInstanceTwo);

        instance.setTokens(tokenInstanceAddress, tokenInstanceTwoAddress);

        tokenInstance.approve(instanceAddress, 100);
        tokenInstanceTwo.approve(instanceAddress, 100);

        instance.addLiquidity(tokenInstanceAddress, 100);
        instance.addLiquidity(tokenInstanceTwoAddress, 100);

        tokenInstance.transfer(_player, 10);
        tokenInstanceTwo.transfer(_player, 10);

        return instanceAddress;
    }

    function validateInstance(address payable _instance, address) public view override returns (bool) {
        address token1 = Dex(_instance).token1();
        address token2 = Dex(_instance).token2();
        return IERC20(token1).balanceOf(_instance) == 0 || ERC20(token2).balanceOf(_instance) == 0;
    }
}