// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "@yield-protocol/utils-v2/src/token/IERC20.sol";

interface IJoin {
    /// @dev asset managed by this contract
    function asset() external view returns (address);

    /// @dev amount of assets held by this contract
    function storedBalance() external view returns (uint256);

    /// @dev Add tokens to this contract.
    function join(address user, uint128 wad) external returns (uint128);

    /// @dev Remove tokens to this contract.
    function exit(address user, uint128 wad) external returns (uint128);

    /// @dev Retrieve any tokens other than the `asset`. Useful for airdropped tokens.
    function retrieve(IERC20 token, address to) external;
}