// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./IERC5095.sol";
import "./IJoin.sol";
import "./IOracle.sol";

interface IFYToken is IERC5095 {

    /// @dev Oracle for the savings rate.
    function oracle() view external returns (IOracle);

    /// @dev Source of redemption funds.
    function join() view external returns (IJoin); 

    /// @dev Asset to be paid out on redemption.
    function underlying() view external returns (address);

    /// @dev Yield id of the asset to be paid out on redemption.
    function underlyingId() view external returns (bytes6);

    /// @dev Time at which redemptions are enabled.
    function maturity() view external returns (uint256);

    /// @dev Spot price (exchange rate) between the base and an interest accruing token at maturity, set to 2^256-1 before maturity
    function chiAtMaturity() view external returns (uint256);
    
    /// @dev Record price data at maturity
    function mature() external;

    /// @dev Mint fyToken providing an equal amount of underlying to the protocol
    function mintWithUnderlying(address to, uint256 amount) external;

    /// @dev Burn fyToken after maturity for an amount of underlying.
    function redeem(address to, uint256 amount) external returns (uint256);

    /// @dev Mint fyToken.
    /// This function can only be called by other Yield contracts, not users directly.
    /// @param to Wallet to mint the fyToken in.
    /// @param fyTokenAmount Amount of fyToken to mint.
    function mint(address to, uint256 fyTokenAmount) external;

    /// @dev Burn fyToken.
    /// This function can only be called by other Yield contracts, not users directly.
    /// @param from Wallet to burn the fyToken from.
    /// @param fyTokenAmount Amount of fyToken to burn.
    function burn(address from, uint256 fyTokenAmount) external;
}