// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;

import {FlashLoanSimpleReceiverBase} from "@aave/core-v3/contracts/flashloan/base/FlashLoanSimpleReceiverBase.sol";

contract FlashLoanArbitrage is FlashLoanSimpleReceiverBase {
    
    function startArbitrage(address asset, uint256 amount) external {
        // 1. Request the flash loan from Aave V3 Pool
        // This will trigger Aave to send us funds and call executeOperation
        POOL.flashLoanSimple(
            address(this),
            asset,
            amount,
            "",
            0
        );
    }

    // 2. Aave invokes this callback after sending us the requested asset
    function executeOperation(
        address asset,
        uint256 amount,
        uint256 premium,
        address initiator,
        bytes calldata params
    ) external override returns (bool) {
        // 3. => Execute Arbitrage Logic Here <=
        // swapExactTokensForTokens (DEX A) -> swapTokensForExactTokens (DEX B)
        
        // 4. Approve Aave to pull the repayment (Principal + 0.05% premium)
        uint256 amountToOwe = amount + premium;
        IERC20(asset).approve(address(POOL), amountToOwe);
        
        // Any remaining tokens in this contract constitute pure profit.
        return true;
    }
}