using Godot;
using System;

public partial class TAS_System : Node
{
    private double _frameLength = 0.1;
    private bool _isIncrementingFrames = false;
    private double _timeSinceLastFrame;
    private int _currentFrame = 0;
    private int _lastAdvancedFrame = 0;

    public double FrameLength
    {
        get { return this._frameLength; }
        set { this._frameLength = value; }
    }

    public bool IsIncrementingFrames
    {
        get { return this._isIncrementingFrames; }
        private set { this._isIncrementingFrames = value; }
    }

    private double TimeSinceLastFrame
    {
        get { return this._timeSinceLastFrame; }
        set { this._timeSinceLastFrame = value; }
    }

    public int CurrentFrame
    {
        get { return this._currentFrame; }
        private set { this._currentFrame = value; }
    }

    /// <summary>
    /// The last frame that can be advanced to. This will
    /// only be greater than CurrentFrame after the player
    /// regresses frames, and will be equal to CurrentFrame
    /// when the player has just done an action.
    /// </summary>
    /// <value></value>
    public int LastAdvancedFrame
    {
        get { return this._lastAdvancedFrame; }
        private set { this._lastAdvancedFrame = value; }
    }

    /// <summary>
    /// Signal is emitted whenever the current frame is incremented.
    /// </summary>
    /// <param name="newFrame"></param>
    [Signal]
    public delegate void FrameIncrementedEventHandler(int newFrame);

    [Signal]
    public delegate void FramesAdvancedEventHandler(int startFrame, int endFrame);

    [Signal]
    public delegate void FramesRegressedEventHandler(int startFrame, int endFrame);


    public void StartIncrementingFrames()
    {
        this.IsIncrementingFrames = true;
    }

    public void StopIncrementingFrames()
    {
        this.IsIncrementingFrames = false;
    }

    public void ResetFrameCount()
    {
        this.CurrentFrame = 0;
        this.LastAdvancedFrame = 0;
    }

    // Returns how many frames it could successfully advance
    public int Advance(int numFrames)
    {
        int newFrame = Math.Min(this.CurrentFrame + numFrames, this.LastAdvancedFrame);
        int framesAdvanced = newFrame - this.CurrentFrame;
        EmitSignal(SignalName.FramesAdvanced, this.CurrentFrame, newFrame);
        this.CurrentFrame = newFrame;
        return framesAdvanced;
    }

    // Returns how many frames it could successfully regress
    public int Regress(int numFrames)
    {
        int newFrame = Math.Max(this.CurrentFrame - numFrames, 0);
        int framesRegressed = newFrame - this.CurrentFrame;
        EmitSignal(SignalName.FramesRegressed, this.CurrentFrame, newFrame);
        this.CurrentFrame = newFrame;
        return framesRegressed;
    }

    /// <summary>
    /// Gets rid of advanced frames.
    /// </summary>
    public void DiscardAdvancedFrames()
    {
        this.LastAdvancedFrame = this.CurrentFrame;
    }

    public override void _PhysicsProcess(double delta)
    {
        if (this.IsIncrementingFrames)
        {
            this.TimeSinceLastFrame += delta;
            if (this.TimeSinceLastFrame >= this.FrameLength)
            {
                this.CurrentFrame++;
                this.LastAdvancedFrame = this.CurrentFrame;
                EmitSignal(SignalName.FrameIncremented, this.CurrentFrame);
                this.TimeSinceLastFrame = 0 + (this.TimeSinceLastFrame - this.FrameLength);
            }
        }

        // GD.Print(CurrentFrame);
    }

    // public void Test()
    // {
    //     GD.Print("test123");

    //     // EmitSignal(SignalName.TestSignal, "test456");
    // }
}