using System;

using UnityEngine;

using Framework.Services;

namespace Framework.Cameras {

  /// <summary>Provides access to the current camera</summary>
  public class CameraManager : Service, ICameraManager {

    /// <summary>Triggered when the active camera changes</summary>
    public event Action<Camera> CameraChanged;

    /// <summary>Camera that is currently active</summary>
    /// <remarks>
    ///   By informing the camera manager about which camera is being used, other services
    ///   such as a background music or ambient sound service can keep their audio sources
    ///   attached to the active camera.
    /// </remarks>
    public Camera ActiveCamera {
      get {
        if(!ReferenceEquals(Camera.main, this.activeCamera)) {
          this.activeCamera = Camera.main;
          OnCameraChanged();
        }

        return this.activeCamera;
      }
      set {
        if(!ReferenceEquals(value, this.activeCamera)) {
          this.activeCamera = value;
          OnCameraChanged();
        }
      }
    }

    /// <summary>Fires the CameraChanged event</summary>
    protected virtual void OnCameraChanged() {
      Debug.Log("New active camera is " + this.activeCamera.name);

      const bool disablePrevious = true;
      CameraHelper.ActivateCamera(this.activeCamera, disablePrevious);

      if(CameraChanged != null) {
        CameraChanged(this.activeCamera);
      }
    }

    /// <summary>Camera that is currently active</summary>
    private Camera activeCamera;

  }

} // namespace Framework.Cameras