equalizer flash loan

equalizer_flash_loan.sol

// SPDX-License-Identifier: MIT
pragma solidity 0.8.4;

interface IERC20 {
    function approve(address spender, uint256 amount) external returns (bool);
}

interface IERC3156FlashBorrower {
    function onFlashLoan(
        address initiator,
        address token,
        uint256 amount,
        uint256 fee,
        bytes calldata data
    ) external returns (bytes32);
}

contract FlashBorrowerExample is IERC3156FlashBorrower {
    uint256 private constant MAX_INT = type(uint256).max;
    address private flashLoanProvider; // Address of the flash loan provider

    // Event for logging the execution result
    event ExecutionResult(bool success, bytes data);

    // Constructor to set the flash loan provider's address
    constructor(address _flashLoanProvider) {
        flashLoanProvider = _flashLoanProvider;
    }

    function onFlashLoan(
        address initiator,
        address token,
        uint256 amount,
        uint256 fee,
        bytes calldata data
    ) external override returns (bytes32) {
        require(msg.sender == flashLoanProvider, "FlashBorrower: Invalid flash loan provider");

        // Approve the token for the flash loan fee
        require(IERC20(token).approve(msg.sender, amount + fee), "FlashBorrower: Approval failed");

        // Decode the call data and execute the intended operation
        (address target, bytes memory callData) = abi.decode(data, (address, bytes));
        
        // Execute the call
        (bool success, bytes memory returnData) = target.call(callData);
        emit ExecutionResult(success, returnData);

        // Return success to the lender
        return keccak256('ERC3156FlashBorrower.onFlashLoan');
    }

    // Additional functions and logic as needed
}