#if HAVE_NODECANVAS

using System;

using UnityEngine;

using ParadoxNotion.Design;
using NodeCanvas.Framework;

namespace Framework.Cameras {

  /// <summary>Fades a camera in or out</summary>
  [Category("Camera")]
  [Description("Fades a camera in or out")]
  public class FadeCameraTask : ActionTask {

    /// <summary>Camera that will be faded in or out</summary>
    [RequiredField]
    public BBParameter<Camera> Camera;

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

    /// <summary>Fade level the camera will begin with</summary>
    public float StartFadeLevel;
    /// <summary>Fade level the camera will end with</summary>
    public float TargetFadeLevel;

    /// <summary>Summary of what this action does</summary>
    protected override string info {
      get {
        if(this.Length == 0.0f) {
          if(this.TargetFadeLevel == 0.0f) {
            return "Set Camera Faded In";
          } else if(this.TargetFadeLevel == 1.0f) {
            return "Set Camera Faded Out";
          } else {
            return "Set Camera Faded " + this.TargetFadeLevel.ToString();
          }
        } else if(this.TargetFadeLevel > this.StartFadeLevel) {
          return "Fade Camera Out";
        } else if(this.TargetFadeLevel < this.StartFadeLevel) {
          return "Fade Camera In";
        } else {
          return "Keep Camera Faded";
        }
      }
    }

    /// <summary>Called once when the action is executed</summary>
    protected override void OnExecute() {
      this.cameraFader = this.Camera.value.GetComponent<CameraFader>();
      if(this.cameraFader == null) {
        Debug.LogWarning(
          "Camera '" + this.Camera.name + "' is missing the CameraFader " +
          "component. Camera fading will not work."
        );
      }
    }

    /// <summary>
    ///   Called every frame, if and while the action is running and until it ends
    /// </summary>
    protected override void OnUpdate() {
      if(this.cameraFader != null) {
        float level = Mathf.Lerp(
          this.StartFadeLevel, this.TargetFadeLevel, (elapsedTime / this.Length)
        );
        level *= level;

        this.cameraFader.FadeLevel = level;
      }

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

    /// <summary>Called once when the task ends for any reason</summary>
    protected override void OnStop() {
      base.OnStop();

      if(this.cameraFader != null) {
        this.cameraFader.FadeLevel = this.TargetFadeLevel;
      }
    }

    /// <summary>Camera controller through which the fading will be performed</summary>
    [NonSerialized]
    private CameraFader cameraFader;

  }

} // namespace Framework.Cameras

#endif // HAVE_NODECANVAS