using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading;

using System.Diagnostics;

namespace MapStudio.UI

{

/// <summary>

/// Represents a timer to control the game calculations seperate from rendering.

/// </summary>

public class GameTimer : IDisposable

{

/// <summary>

/// Detemines to pause or play the timer.

/// </summary>

public GameState TimerState = GameState.Pause;

/// <summary>

/// Determines if the current timer is being played.

/// </summary>

public bool IsPlaying => TimerState == GameState.Playing;

/// <summary>

/// A callback to run before the frame update event.

/// </summary>

public EventHandler OnFrameUpdate;

private Stopwatch stopWatch;

private System.Timers.Timer animationTimer;

private float FrameRate = 60.0f;

private float CurrentFrame;

private int timing = 0;

private bool disposed = false;

public GameTimer()

{

stopWatch = new Stopwatch();

stopWatch.Start();

animationTimer = new System.Timers.Timer()

{

Interval = (int)(1000.0f / 60.0f),

};

animationTimer.Elapsed += timer_Tick;

}

void timer_Tick(object sender, EventArgs e) {

if (disposed) return;

CurrentFrame += 1.0f;

OnFrameAdvanced();

}

/// <summary>

/// Updates the current frame rate of the timer.

/// </summary>

public void UpdateFramerate(float rate) {

FrameRate = rate;

animationTimer.Interval = (int)(1000.0f / FrameRate);

}

/// <summary>

/// Activates the timer to start playing.

/// </summary>

public void Play()

{

animationTimer.Start();

TimerState = GameState.Playing;

}

/// <summary>

/// Pauses the timer if it is currently playing.

/// </summary>

public void Pause()

{

animationTimer.Stop();

TimerState = GameState.Pause;

}

private void OnFrameAdvanced()

{

timing += (int)stopWatch.ElapsedMilliseconds;

stopWatch.Reset();

stopWatch.Start();

//Update by interval

if (timing > 16)

{

timing = timing % 16;

OnFrameUpdate?.Invoke(this, EventArgs.Empty);

OnUpdateFrame(CurrentFrame);

}

}

/// <summary>

/// Method for updating the frame during the timer playback.

/// </summary>

/// <param name="frame"></param>

protected virtual void OnUpdateFrame(float frame)

{

}

/// <summary>

/// Disposes the timer.

/// </summary>

public void Dispose()

{

animationTimer.Stop();

animationTimer.Dispose();

disposed = true;

TimerState = GameState.Pause;

stopWatch.Stop();

}

public enum GameState

{

Playing,

Pause,

}

}

}