// 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 Feature that allows spending token allowances.
interface ITokenSpenderFeature {

    /// @dev Transfers ERC20 tokens from `owner` to `to`.
    ///      Only callable from within.
    /// @param token The token to spend.
    /// @param owner The owner of the tokens.
    /// @param to The recipient of the tokens.
    /// @param amount The amount of `token` to transfer.
    function _spendERC20Tokens(
        IERC20TokenV06 token,
        address owner,
        address to,
        uint256 amount
    )
        external;

    /// @dev Gets the maximum amount of an ERC20 token `token` that can be
    ///      pulled from `owner`.
    /// @param token The token to spend.
    /// @param owner The owner of the tokens.
    /// @return amount The amount of tokens that can be pulled.
    function getSpendableERC20BalanceOf(IERC20TokenV06 token, address owner)
        external
        view
        returns (uint256 amount);

    /// @dev Get the address of the allowance target.
    /// @return target The target of token allowances.
    function getAllowanceTarget() external view returns (address target);
}
