// Copyright (c) 2023 Dominic Masters
// 
// This software is released under the MIT License.
// https://opensource.org/licenses/MIT

#pragma once
#include "scene/SceneItem.hpp"
#include "display/RenderTarget.hpp"

namespace Dawn {
  enum class CameraType {
    PERSPECTIVE,
    ORTHOGONAL
  };

  class Camera final : public SceneComponent {
    private:
      std::shared_ptr<RenderTarget> renderTarget;
      std::function<void()> onResizeListener;

    public:
      Event<std::shared_ptr<RenderTarget>, float_t, float_t> onResize;
      float_t clipNear = 0.01f;
      float_t clipFar = 1000.0f;
      enum CameraType type = CameraType::PERSPECTIVE;

      float_t fov = 0.785398f;

      float_t orthoLeft = -1.0f;
      float_t orthoRight = 1.0f;
      float_t orthoBottom = -1.0f;
      float_t orthoTop = 1.0f;

      void onInit() override;
      void onDispose() override;
      void load(const SceneComponentLoadContext &ctx) override;

      /**
       * Returns the aspect ratio that the camera is using. In future I may 
       * allow you to specify a custom ratio for stylistic reasons but for now I
       * just take the ratio of the specific frame buffer.
       * 
       * @return The aspect ratio as a ratio of w/h.
       */
      float_t getAspect();

      /**
       * Returns the render target for this camera.
       * 
       * @return Render target.
       */
      std::shared_ptr<RenderTarget> getRenderTarget();

      /**
       * Returns the projection matrix for this camera.
       * 
       * @return Projection matrix.
       */
      glm::mat4 getProjection();

      /**
       * Shorthand for getItem()->lookAtPixelPerfect()
       * 
       * @param position Position to look from.
       * @param look Position to look at.
       * @param scale Scale to use. At scale 1 then the centerest pixel is 1:1.
       * @return The Z distance that was calculated.
       */
      float_t lookAtPixelPerfect(
        const glm::vec3 &position,
        const glm::vec3 &look,
        const float_t &scale = 1.0f
      );

      /**
       * Sets the render target for this camera.
       * 
       * @param renderTarget The render target to set.
       */
      void setRenderTarget(const std::shared_ptr<RenderTarget> renderTarget);
  };
}