aave-protocol-v2/contracts/adapters/UniswapRepayAdapter.sol
2020-10-27 11:22:16 -03:00

72 lines
2.7 KiB
Solidity

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.6.8;
pragma experimental ABIEncoderV2;
import {BaseUniswapAdapter} from './BaseUniswapAdapter.sol';
import {ILendingPoolAddressesProvider} from '../interfaces/ILendingPoolAddressesProvider.sol';
import {IUniswapV2Router02} from '../interfaces/IUniswapV2Router02.sol';
import {IFlashLoanReceiver} from '../flashloan/interfaces/IFlashLoanReceiver.sol';
import {IERC20} from '../dependencies/openzeppelin/contracts/IERC20.sol';
/**
* @title UniswapRepayAdapter
* @notice Uniswap V2 Adapter to perform a repay of a debt using a flash loan.
* @author Aave
**/
contract UniswapRepayAdapter is BaseUniswapAdapter, IFlashLoanReceiver {
constructor(
ILendingPoolAddressesProvider _addressesProvider,
IUniswapV2Router02 _uniswapRouter
)
public
BaseUniswapAdapter(_addressesProvider, _uniswapRouter)
{}
/**
* @dev Swaps the received reserve amount into the asset specified in the params. The received funds from the swap are
* then used to repay a debt on the protocol on behalf of the user.
* The user should give this contract allowance to pull the ATokens in order to withdraw the underlying asset and
* repay the flash loan.
* @param assets Address to be swapped
* @param amounts Amount of the reserve to be swapped
* @param premiums Fee of the flash loan
* @param params Additional variadic field to include extra params. Expected parameters:
* address assetToSwapTo Address of the reserve to be swapped to and deposited
* address user The address of the user
* uint256 leftOverAction Flag indicating what to do with the left over balance from the swap:
* (0) Deposit back
* (1) Direct transfer to user
* uint256 repayAmount Amount of debt to be repaid
* uint256 rateMode The rate modes of the debt to be repaid
*/
function executeOperation(
address[] calldata assets,
uint256[] calldata amounts,
uint256[] calldata premiums,
bytes calldata params
) external override returns (bool) {
(
address assetToSwapTo,
address user,
uint256 leftOverAction,
uint256 repayAmount,
uint256 rateMode
) = abi.decode(params, (address, address, uint256, uint256, uint256));
swapTokensForExactTokens(assets[0], assetToSwapTo, amounts[0], repayAmount);
// Repay debt
IERC20(assetToSwapTo).approve(address(pool), repayAmount);
pool.repay(assetToSwapTo, repayAmount, rateMode, user);
uint256 flashLoanDebt = amounts[0].add(premiums[0]);
pullATokenAndRepayFlashLoan(assets[0], user, flashLoanDebt);
// Take care of reserve leftover from the swap
sendLeftOver(assets[0], flashLoanDebt, leftOverAction, user);
return true;
}
}