/*
 *  Copyright (C) 2016-2018 Team Kodi
 *  This file is part of Kodi - https://kodi.tv
 *
 *  SPDX-License-Identifier: GPL-2.0-or-later
 *  See LICENSES/README.md for more information.
 */

#pragma once

#include <atomic>

#include "threads/Event.h"
#include "threads/Thread.h"

namespace KODI
{
namespace RETRO
{
  class IGameLoopCallback
  {
  public:
    virtual ~IGameLoopCallback() = default;

    /*!
     * \brief The next frame is being shown
     */
    virtual void FrameEvent() = 0;

    /*!
     * \brief The prior frame is being shown
     */
    virtual void RewindEvent() = 0;
  };

  class CGameLoop : protected CThread
  {
  public:
    CGameLoop(IGameLoopCallback* callback, double fps);

    virtual ~CGameLoop();

    void Start();
    void Stop();

    double FPS() const { return m_fps; }

    double GetSpeed() const { return m_speedFactor; }
    void SetSpeed(double speedFactor);
    void PauseAsync();

  protected:
    // implementation of CThread
    virtual void Process() override;

  private:
    double FrameTimeMs() const;
    double SleepTimeMs() const;
    double NowMs() const;

    IGameLoopCallback* const m_callback;
    const double             m_fps;
    std::atomic<double>      m_speedFactor;
    double                   m_lastFrameMs;
    mutable double           m_adjustTime;
    CEvent                   m_sleepEvent;
  };
}
}
