#if HAVE_NODECANVAS

using System;

using UnityEngine;

using ParadoxNotion.Design;
using NodeCanvas.Framework;

using Framework.Support;

using CanvasGroup = UnityEngine.CanvasGroup;

namespace Framework.UI {

  /// <summary>Fades a CanvasGroup (UGUI) in or out</summary>
  [Category("UI")]
  [Description("Fades a CanvasGroup (UGUI) in or out")]
  public class FadeCanvasGroupTask : ActionTask {

    /// <summary>Canvas group that will be faded</summary>
    [RequiredField]
    //public Canvas CanvasToFade;
    public BBParameter<CanvasGroup> CanvasToFade;

    /// <summary>Duration of the action in seconds</summary>
    public float Length;

    /// <summary>How long the fade-in should take in seconds</summary>
    public float FadeInDuration;

    /// <summary>How long the fade-out should take in seconds</summary>
    public float FadeOutDuration;

    /// <summary>Provides a summary description for the task</summary>
    protected override string info {
      get {
        if(this.CanvasToFade == null) {
          return "Fade CanvasGroup";
        } else {
          return "Fade " + this.CanvasToFade.name;
        }
      }
    }

    /// <summary>Called once when the action is executed</summary>
    protected override void OnExecute() { }

    /// <summary>
    ///   Called every frame, if and while the action is running and until it ends
    /// </summary>
    protected override void OnUpdate() {
      if(this.CanvasToFade.value != null) {
        float opacity = InterpolationHelper.InterpolateFade(
          elapsedTime, this.Length, this.FadeInDuration, this.FadeOutDuration
        );

        opacity *= opacity;

        this.CanvasToFade.value.alpha = opacity;
      }

      if(elapsedTime >= this.Length) {
        EndAction();
      }
    }

    /// <summary>Called whenever the action ends due to any reason</summary>
    protected override void OnStop() {
      //cutscene.value.Stop();
    }

  }

} // namespace Framework.UI

#endif // HAVE_NODECANVAS