// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;

interface IStrategy {
    // Send the assets to the Strategy and call skim to invest them
    function skim(uint256 amount) external;

    // Harvest any profits made converted to the asset and pass them to the caller
    function harvest(uint256 balance, address sender) external returns (int256 amountAdded);

    // Withdraw assets. The returned amount can differ from the requested amount due to rounding.
    // The actualAmount should be very close to the amount. The difference should NOT be used to report a loss. That's what harvest is for.
    function withdraw(uint256 amount) external returns (uint256 actualAmount);

    // Withdraw all assets in the safest way possible. This shouldn't fail.
    function exit(uint256 balance) external returns (int256 amountAdded);
}