#if HAVE_NODECANVAS

using System;

using UnityEngine;

using ParadoxNotion.Design;
using NodeCanvas.Framework;

using Framework.Support;

namespace Framework.Cinematics {

  /// <summary>Fades a standard shader material using its alpha channel</summary>
  [Category("Material")]
  [Description("Fades a CanvasGroup (UGUI) in or out")]
  public class FadeMaterialAlphaTask : ActionTask {

    /// <summary>Game object whose materials will be faded</summary>
    [RequiredField]
    public BBParameter<GameObject> ObjectToFade;

    /// <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>Summary of what this action does</summary>
    protected override string info {
      get { return "Fade Material"; }
    }

    /// <summary>Called once when the action is executed</summary>
    protected override void OnExecute() {
      this.materials = MaterialHelper.GetMeshMaterials(this.ObjectToFade.value);

      int materialCount = this.materials.Length;

      this.previousAlpha = new float[materialCount];
      for(int index = 0; index < materialCount; ++index) {
        previousAlpha[index] = this.materials[index].color.a;
      }
    }

    /// <summary>
    ///   Called every frame, if and while the action is running and until it ends
    /// </summary>
    protected override void OnUpdate() {
      int materialCount = this.materials.Length;

      float opacity = InterpolationHelper.InterpolateFade(
        elapsedTime, this.Length, this.FadeInDuration, this.FadeOutDuration
      );
      opacity *= opacity;

      for(int index = 0; index < materialCount; ++index) {
        Color color = this.materials[index].color;
        color.a = opacity;
        //color.a = Easing.Ease(this.interpolation, 0.0f, this.previousAlpha[index], weight);
        //color.a = Easing.Ease(this.interpolation, 0.0f, 1.0f, weight);
        this.materials[index].color = color;
      }

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

    /// <summary>All materials in whom the opacity level will be changed</summary>
    [NonSerialized]
    private Material[] materials;
    /// <summary>Opacity levels the materials had before the action</summary>
    [NonSerialized]
    private float[] previousAlpha;

  }

} // namespace Framework.Cinematics

#endif // HAVE_NODECANVAS