// SPDX-License-Identifier: Apache-2.0
/*

  Copyright 2020 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.

*/

pragma solidity ^0.6.5;
pragma experimental ABIEncoderV2;

import "@0x/contracts-erc20/contracts/src/v06/IERC20TokenV06.sol";


/// @dev A transformation callback used in `TransformERC20.transformERC20()`.
interface IERC20Transformer {

    /// @dev Context information to pass into `transform()` by `TransformERC20.transformERC20()`.
    struct TransformContext {
        // The caller of `TransformERC20.transformERC20()`.
        address payable sender;
        // The recipient address, which may be distinct from `sender` e.g. in
        // meta-transactions.
        address payable recipient;
        // Arbitrary data to pass to the transformer.
        bytes data;
    }

    /// @dev Called from `TransformERC20.transformERC20()`. This will be
    ///      delegatecalled in the context of the FlashWallet instance being used.
    /// @param context Context information.
    /// @return success The success bytes (`LibERC20Transformer.TRANSFORMER_SUCCESS`).
    function transform(TransformContext calldata context)
        external
        returns (bytes4 success);
}
