// 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 "component/display/IRenderableComponent.hpp"
#include "display/shader/UIShader.hpp"

namespace Dawn {
  class UIElement;

  class UICanvas :
    public SceneComponent,
    public IRenderableComponent
  {
    private:
      std::shared_ptr<Mesh> mesh;
      UIShaderData data;
      std::vector<std::shared_ptr<UIElement>> elements;

      size_t quadCount = 0;
      shadertexturebinding_t nextBinding = 0;
      std::unordered_map<
        shadertexturebinding_t, std::shared_ptr<Texture>
      > textures;
      std::map<
        std::shared_ptr<Texture>, shadertexturebinding_t
      > textureBindings;
      
      std::vector<std::shared_ptr<IRenderPass>> passes;
      
    protected:
      virtual void onInit() override;
      virtual void onDispose() override;

      /**
       * Flushes all pending quads to the render pass. This doesn't actually
       * render anything, it just flushes the data buffer to a new pass.
       */
      void flushPass();

    public:
      std::vector<std::shared_ptr<IRenderPass>> getPasses(
        struct RenderPassContext &ctx
      ) override;

      /**
       * Adds a quad to the canvas and performs a flush if necessary.
       * 
       * @param quad The quad to add.
       * @param uvs The UVs to use for the quad.
       * @param color The color to use for the quad.
       * @param style Style that the quad should be rendered in.
       * @param texture The texture to use for the quad, can be null.
       */
      void addQuad(
        const glm::vec4 quad,
        const glm::vec4 uvs,
        const struct Color color,
        const enum UIShaderQuadStyle style,
        const std::shared_ptr<Texture> texture = nullptr
      );

      /**
       * Adds a component to the canvas.
       * 
       * @param component The component to add.
       */
      void addElement(const std::shared_ptr<UIElement> component);
  };
}