// SPDX-License-Identifier: GPL-3.0

pragma solidity 0.8.6;

import "@pooltogether/pooltogether-rng-contracts/contracts/RNGInterface.sol";
import "./IDrawBuffer.sol";

/** @title  IDrawBeacon
  * @author PoolTogether Inc Team
  * @notice The DrawBeacon interface.
*/
interface IDrawBeacon {

    /// @notice Draw struct created every draw
    /// @param winningRandomNumber The random number returned from the RNG service
    /// @param drawId The monotonically increasing drawId for each draw
    /// @param timestamp Unix timestamp of the draw. Recorded when the draw is created by the DrawBeacon.
    /// @param beaconPeriodStartedAt Unix timestamp of when the draw started
    /// @param beaconPeriodSeconds Unix timestamp of the beacon draw period for this draw.
    struct Draw {
        uint256 winningRandomNumber;
        uint32 drawId;
        uint64 timestamp;
        uint64 beaconPeriodStartedAt;
        uint32 beaconPeriodSeconds;
    }

    /**
     * @notice Emit when a new DrawBuffer has been set.
     * @param newDrawBuffer       The new DrawBuffer address
     */
    event DrawBufferUpdated(IDrawBuffer indexed newDrawBuffer);

    /**
     * @notice Emit when a draw has opened.
     * @param startedAt Start timestamp
     */
    event BeaconPeriodStarted(uint64 indexed startedAt);

    /**
     * @notice Emit when a draw has started.
     * @param rngRequestId  draw id
     * @param rngLockBlock  Block when draw becomes invalid
     */
    event DrawStarted(uint32 indexed rngRequestId, uint32 rngLockBlock);

    /**
     * @notice Emit when a draw has been cancelled.
     * @param rngRequestId  draw id
     * @param rngLockBlock  Block when draw becomes invalid
     */
    event DrawCancelled(uint32 indexed rngRequestId, uint32 rngLockBlock);

    /**
     * @notice Emit when a draw has been completed.
     * @param randomNumber  Random number generated from draw
     */
    event DrawCompleted(uint256 randomNumber);

    /**
     * @notice Emit when a RNG service address is set.
     * @param rngService  RNG service address
     */
    event RngServiceUpdated(RNGInterface indexed rngService);

    /**
     * @notice Emit when a draw timeout param is set.
     * @param rngTimeout  draw timeout param in seconds
     */
    event RngTimeoutSet(uint32 rngTimeout);

    /**
     * @notice Emit when the drawPeriodSeconds is set.
     * @param drawPeriodSeconds Time between draw
     */
    event BeaconPeriodSecondsUpdated(uint32 drawPeriodSeconds);

    /**
     * @notice Returns the number of seconds remaining until the beacon period can be complete.
     * @return The number of seconds remaining until the beacon period can be complete.
     */
    function beaconPeriodRemainingSeconds() external view returns (uint64);

    /**
     * @notice Returns the timestamp at which the beacon period ends
     * @return The timestamp at which the beacon period ends.
     */
    function beaconPeriodEndAt() external view returns (uint64);

    /**
     * @notice Returns whether a Draw can be started.
     * @return True if a Draw can be started, false otherwise.
     */
    function canStartDraw() external view returns (bool);

    /**
     * @notice Returns whether a Draw can be completed.
     * @return True if a Draw can be completed, false otherwise.
     */
    function canCompleteDraw() external view returns (bool);

    /**
     * @notice Calculates when the next beacon period will start.
     * @param time The timestamp to use as the current time
     * @return The timestamp at which the next beacon period would start
     */
    function calculateNextBeaconPeriodStartTime(uint64 time) external view returns (uint64);

    /**
     * @notice Can be called by anyone to cancel the draw request if the RNG has timed out.
     */
    function cancelDraw() external;

    /**
     * @notice Completes the Draw (RNG) request and pushes a Draw onto DrawBuffer.
     */
    function completeDraw() external;

    /**
     * @notice Returns the block number that the current RNG request has been locked to.
     * @return The block number that the RNG request is locked to
     */
    function getLastRngLockBlock() external view returns (uint32);

    /**
     * @notice Returns the current RNG Request ID.
     * @return The current Request ID
     */
    function getLastRngRequestId() external view returns (uint32);

    /**
     * @notice Returns whether the beacon period is over
     * @return True if the beacon period is over, false otherwise
     */
    function isBeaconPeriodOver() external view returns (bool);

    /**
     * @notice Returns whether the random number request has completed.
     * @return True if a random number request has completed, false otherwise.
     */
    function isRngCompleted() external view returns (bool);

    /**
     * @notice Returns whether a random number has been requested
     * @return True if a random number has been requested, false otherwise.
     */
    function isRngRequested() external view returns (bool);

    /**
     * @notice Returns whether the random number request has timed out.
     * @return True if a random number request has timed out, false otherwise.
     */
    function isRngTimedOut() external view returns (bool);

    /**
     * @notice Allows the owner to set the beacon period in seconds.
     * @param beaconPeriodSeconds The new beacon period in seconds.  Must be greater than zero.
     */
    function setBeaconPeriodSeconds(uint32 beaconPeriodSeconds) external;

    /**
     * @notice Allows the owner to set the RNG request timeout in seconds. This is the time that must elapsed before the RNG request can be cancelled and the pool unlocked.
     * @param rngTimeout The RNG request timeout in seconds.
     */
    function setRngTimeout(uint32 rngTimeout) external;

    /**
     * @notice Sets the RNG service that the Prize Strategy is connected to
     * @param rngService The address of the new RNG service interface
     */
    function setRngService(RNGInterface rngService) external;

    /**
     * @notice Starts the Draw process by starting random number request. The previous beacon period must have ended.
     * @dev The RNG-Request-Fee is expected to be held within this contract before calling this function
     */
    function startDraw() external;

    /**
     * @notice Set global DrawBuffer variable.
     * @dev    All subsequent Draw requests/completions will be pushed to the new DrawBuffer.
     * @param newDrawBuffer DrawBuffer address
     * @return DrawBuffer
     */
    function setDrawBuffer(IDrawBuffer newDrawBuffer) external returns (IDrawBuffer);
}