#pragma once

#include <GL/glew.h>
#include <GLFW/glfw3.h>

#include "WallpaperEngine/Assets/CContainer.h"
#include "WallpaperEngine/Audio/CAudioContext.h"

#include "WallpaperEngine/Core/CWallpaper.h"
#include "WallpaperEngine/Core/CScene.h"
#include "WallpaperEngine/Core/CVideo.h"

#include "WallpaperEngine/Render/CRenderContext.h"
#include "WallpaperEngine/Render/CFBO.h"
#include "WallpaperEngine/Render/Helpers/CContextAware.h"

#include "CWallpaperState.h"

using namespace WallpaperEngine::Assets;
using namespace WallpaperEngine::Audio;

namespace WallpaperEngine::Render
{
    namespace Helpers
    {
        class CContextAware;
    }

    class CWallpaper : public Helpers::CContextAware
    {
    public:
        template<class T> const T* as () const { assert (is<T> ()); return (const T*) this; }
        template<class T> T* as () { assert (is<T> ()); return (T*) this; }

        template<class T> bool is () { return this->m_type == T::Type; }

        ~CWallpaper ();

        /**
         * Performs a render pass of the wallpaper
         */
        void render (glm::ivec4 viewport, bool vflip);

        /**
         * @return The container to resolve files for this wallpaper
         */
        [[nodiscard]] CContainer* getContainer () const;

        /**
         * @return The current audio context for this wallpaper
         */
        CAudioContext& getAudioContext ();

        /**
         * @return The scene's framebuffer
         */
        [[nodiscard]] virtual GLuint getWallpaperFramebuffer () const;
        /**
         * @return The scene's texture
         */
        [[nodiscard]] virtual GLuint getWallpaperTexture () const;
        /**
         * Creates a new FBO for this wallpaper
         *
         * @param name The name of the FBO
         * @return
         */
        CFBO* createFBO (const std::string& name, ITexture::TextureFormat format, ITexture::TextureFlags flags, float scale, uint32_t realWidth, uint32_t realHeight, uint32_t textureWidth, uint32_t textureHeight);

        /**
         * @return The full FBO list to work with
         */
        [[nodiscard]] const std::map<std::string, CFBO*>& getFBOs () const;
        /**
         * Searches the FBO list for the given FBO
         *
         * @param name
         * @return
         */
        [[nodiscard]] CFBO* findFBO (const std::string& name) const;

        /**
         * @return The main FBO of this wallpaper
         */
        [[nodiscard]] CFBO* getFBO () const;

        /**
         * Updates the UVs coordinates if window/screen/vflip/projection has changed 
         */
        void updateUVs (const glm::ivec4& viewport, const bool vflip);

        /**
         * Updates the destination framebuffer for this wallpaper
         *
         * @param framebuffer
         */
        void setDestinationFramebuffer (GLuint framebuffer);

        /**
         * @return The width of this wallpaper
         */
        [[nodiscard]] virtual uint32_t getWidth () const = 0;

        /**
         * @return The height of this wallpaper
         */
        [[nodiscard]] virtual uint32_t getHeight () const = 0;

        /**
         * Creates a new instance of CWallpaper based on the information provided by the read backgrounds
         *
         * @param wallpaper
         *
         * @return
         */
        static CWallpaper* fromWallpaper (Core::CWallpaper* wallpaper, CRenderContext& context, CAudioContext& audioContext, const CWallpaperState::TextureUVsScaling& scalingMode);

    protected:
        CWallpaper (Core::CWallpaper* wallpaperData, std::string type, CRenderContext& context, CAudioContext& audioContext,  const CWallpaperState::TextureUVsScaling& scalingMode);

        /**
         * Renders a frame of the wallpaper
         */
        virtual void renderFrame (glm::ivec4 viewport) = 0;

        /**
         * Setups OpenGL's framebuffers for ping-pong and scene rendering
         */
        void setupFramebuffers ();

        Core::CWallpaper* m_wallpaperData;

        [[nodiscard]] Core::CWallpaper* getWallpaperData () const;

        /** The FBO used for scene output */
        CFBO* m_sceneFBO;

    private:
        /** The texture used for the scene output */
        GLuint m_texCoordBuffer;
        GLuint m_positionBuffer;
        GLuint m_shader;
        // shader variables
        GLint g_Texture0;
        GLint a_Position;
        GLint a_TexCoord;
        GLuint m_vaoBuffer;
        /** The framebuffer to draw the background to */
        GLuint m_destFramebuffer;
        /** Setups OpenGL's shaders for this wallpaper backbuffer */
        void setupShaders ();
        /** The type of background this wallpaper is */
        std::string m_type;
        /** List of FBOs registered for this wallpaper */
        std::map<std::string, CFBO*> m_fbos;
        /** Audio context that is using this wallpaper */
        CAudioContext& m_audioContext;
        /** Current Wallpaper state */
        CWallpaperState m_state;
    };
}