using Engine.Graphics.Camera;
using Engine.Graphics.Pipeline;
using OpenTK.Mathematics;

namespace Engine.Scene.Component.BuiltIn;

/// <summary>
/// Abstract base class for cameras that provide view and projection matrices.
/// </summary>
public abstract class Camera : Component, ICamera
{
  /// <inheritdoc/>
  public abstract Matrix4 View { get; }

  /// <inheritdoc/>
  public abstract Matrix4 Projection { get; }

  /// <inheritdoc/>
  public Vector2i ScreenSize
  {
    get => _screenSize;
    set
    {
      _screenSize = value;
      AspectRatio = (float)value.X / value.Y;
    }
  }

  /// <summary>
  /// The aspect ratio of the camera, calculated as width divided by height.
  /// </summary>
  public float AspectRatio { get; private set; } = 1;

  /// <summary>
  /// The near clipping plane distance.
  /// </summary>
  public float NearPlane { get; set; }

  /// <summary>
  /// The far clipping plane distance.
  /// </summary>
  public float FarPlane { get; set; }

  /// <summary>
  /// The render layer for the camera.
  /// </summary>
  public RenderLayer RenderLayer { get; set; } = RenderLayer.DEFAULT;


  /// <summary>
  /// The screen size of the camera.
  /// </summary>
  private Vector2i _screenSize = new(1, 1);

  /// <summary>
  /// Initializes a new instance of the <see cref="Camera"/> class.
  /// </summary>
  /// <param name="parNearPlane">The near clipping plane distance.</param>
  /// <param name="parFarPlane">The far clipping plane distance.</param>
  protected Camera(float parNearPlane, float parFarPlane)
  {
    NearPlane = parNearPlane;
    FarPlane = parFarPlane;
  }

  /// <summary>
  /// Converts a screen position to a world position in 3D space.
  /// </summary>
  /// <param name="parScreenPosition">The screen position to convert.</param>
  /// <returns>The corresponding world position.</returns>
  public abstract Vector3 ScreenToWorld(Vector2 parScreenPosition);

  /// <summary>
  /// Converts a world position to a screen position in 2D space.
  /// </summary>
  /// <param name="parWorldPosition">The world position to convert.</param>
  /// <returns>The corresponding screen position.</returns>
  public abstract Vector2 WorldToScreen(Vector3 parWorldPosition);
}