// SPDX-License-Identifier: GPL-3.0

pragma solidity 0.8.6;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

interface IReserve {
    /**
     * @notice Emit when checkpoint is created.
     * @param reserveAccumulated  Total depsosited
     * @param withdrawAccumulated Total withdrawn
     */

    event Checkpoint(uint256 reserveAccumulated, uint256 withdrawAccumulated);
    /**
     * @notice Emit when the withdrawTo function has executed.
     * @param recipient Address receiving funds
     * @param amount    Amount of tokens transfered.
     */
    event Withdrawn(address indexed recipient, uint256 amount);

    /**
     * @notice Create observation checkpoint in ring bufferr.
     * @dev    Calculates total desposited tokens since last checkpoint and creates new accumulator checkpoint.
     */
    function checkpoint() external;

    /**
     * @notice Read global token value.
     * @return IERC20
     */
    function getToken() external view returns (IERC20);

    /**
     * @notice Calculate token accumulation beween timestamp range.
     * @dev    Search the ring buffer for two checkpoint observations and diffs accumulator amount.
     * @param startTimestamp Account address
     * @param endTimestamp   Transfer amount
     */
    function getReserveAccumulatedBetween(uint32 startTimestamp, uint32 endTimestamp)
        external
        returns (uint224);

    /**
     * @notice Transfer Reserve token balance to recipient address.
     * @dev    Creates checkpoint before token transfer. Increments withdrawAccumulator with amount.
     * @param recipient Account address
     * @param amount    Transfer amount
     */
    function withdrawTo(address recipient, uint256 amount) external;
}