// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import "../interfaces/IAavePool.sol";
import "../interfaces/IERC20.sol";

/**
 * @title AaveSupplyBorrow
 * @notice Example contract for supplying collateral and borrowing on Aave v3
 */
contract AaveSupplyBorrow {
    IAavePool public immutable pool;

    constructor(address pool_) {
        pool = IAavePool(pool_);
    }

    /**
     * @notice Supply collateral, enable as collateral, and borrow
     * @param asset The collateral asset to supply
     * @param amount The amount of collateral to supply
     * @param debtAsset The asset to borrow
     * @param borrowAmount The amount to borrow
     */
    function supplyAndBorrow(
        address asset,
        uint256 amount,
        address debtAsset,
        uint256 borrowAmount
    ) external {
        // Step 1: Transfer collateral from user
        IERC20(asset).transferFrom(msg.sender, address(this), amount);

        // Step 2: Approve pool to take collateral
        IERC20(asset).approve(address(pool), amount);

        // Step 3: Supply collateral
        pool.supply(asset, amount, address(this), 0);

        // Step 4: Enable as collateral
        pool.setUserUseReserveAsCollateral(asset, true);

        // Step 5: Borrow (variable rate = 2, stable rate is deprecated)
        pool.borrow(debtAsset, borrowAmount, 2, 0, address(this));

        // Step 6: Transfer borrowed tokens to user
        IERC20(debtAsset).transfer(msg.sender, borrowAmount);
    }

    /**
     * @notice Repay debt and withdraw collateral
     * @param debtAsset The debt asset to repay
     * @param repayAmount The amount to repay
     * @param collateralAsset The collateral asset to withdraw
     * @param withdrawAmount The amount to withdraw
     */
    function repayAndWithdraw(
        address debtAsset,
        uint256 repayAmount,
        address collateralAsset,
        uint256 withdrawAmount
    ) external {
        // Step 1: Transfer repayment tokens from user
        IERC20(debtAsset).transferFrom(msg.sender, address(this), repayAmount);

        // Step 2: Approve pool to take repayment
        IERC20(debtAsset).approve(address(pool), repayAmount);

        // Step 3: Repay debt (variable rate = 2)
        pool.repay(debtAsset, repayAmount, 2, address(this));

        // Step 4: Withdraw collateral
        pool.withdraw(collateralAsset, withdrawAmount, address(this));

        // Step 5: Transfer collateral to user
        IERC20(collateralAsset).transfer(msg.sender, withdrawAmount);
    }
}