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

import {IERC20} from "@openzeppelin/contracts@5.3.0/token/ERC20/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts@5.3.0/token/ERC20/utils/SafeERC20.sol";

library FeeTokenHandler {
  using SafeERC20 for IERC20;

  error ZeroAddressNotAllowed();

  event FeeTokenWithdrawn(address indexed receiver, address indexed feeToken, uint256 amount);

  /// @notice Withdraws the outstanding fee token balances to the fee aggregator.
  /// @param feeTokens The fee tokens to withdraw.
  /// @param feeAggregator The address to withdraw the fee tokens to, cannot be the zero address.
  function _withdrawFeeTokens(
    address[] calldata feeTokens,
    address feeAggregator
  ) internal {
    if (feeAggregator == address(0)) revert ZeroAddressNotAllowed();

    for (uint256 i = 0; i < feeTokens.length; ++i) {
      IERC20 feeToken = IERC20(feeTokens[i]);
      uint256 feeTokenBalance = feeToken.balanceOf(address(this));

      if (feeTokenBalance > 0) {
        feeToken.safeTransfer(feeAggregator, feeTokenBalance);

        emit FeeTokenWithdrawn(feeAggregator, address(feeToken), feeTokenBalance);
      }
    }
  }
}