#pragma once

#include <common/math.hpp>
#include <common/Font.hpp>
#include <common/shapes.hpp>

#include <SDL3/SDL.h>
#include <SDL3/SDL_video.h>
#include <imgui.h>

#include <vector>
#include <memory>


class RSoftwareBackend;
class Renderer;

extern Renderer g_renderer;


enum REntityType : int32_t {
    REntityType_Rectangle,
    REntityType_AlphaBitmap,
    REntityType_Circle,
    REntityType_Text,
};


struct REntity_AlphaBitmap {
    REntityType type;
    AlphaBitmap& bitmap;
    V3F32 pos;
    Color color;
};

struct REntity_Rectangle {
    REntityType type;
    Rectangle rect;
    Color color;
};

struct REntity_Circle {
    REntityType type;
    Circle circle;
    Color color;
};

struct REntity_Text {
    REntityType type;
    std::u32string& text;
    Font& font;
    V3F32 pos;
    Color color;
};


union REntity {
    REntityType type;
    REntity_AlphaBitmap bitmap;
    REntity_Rectangle rect;
    REntity_Circle circle;
    REntity_Text text;
};

struct RSortEntry {
    float z;
    size_t entity_index;
};


class Renderer {
public:
    void Init(SDL_Window* window);


    /* core functions */

    void Draw();
    void Reset();

    void Clear(Color color);
    void PushAlphaBitmap(AlphaBitmap& bitmap, V3F32 pos, Color color);
    void PushRectangle(Rectangle rect, Color color, float z);
    void PushCircle(Circle circle, Color color, float z);
    void PushText(std::u32string& text, Font& font, V3F32 pos, Color color);


    /* helper functions */

    void SetScreenSize(int32_t w, int32_t h);
    void SetCameraSize(float w, float h);


    int32_t WorldXToScreenX(float x);
    int32_t WorldYToScreenY(float y);

    int32_t WorldWidthToScreenWidth(float w);
    int32_t WorldHeightToScreenHeight(float h);


    /* temporary helper functions (from old RGroup api) */

    float GetScale();
    V2F32 ViewPosToScreenPos(V2F32 view_pos);
    V2F32 ViewSizeToScreenSize(V2F32 view_size);
    ImVec2 ViewPosToScreenPosImGui(V2F32 view_pos);
    ImVec2 ViewSizeToScreenSizeImGui(V2F32 view_size);



public:
    SDL_Window* m_window;

    int32_t m_screen_w;
    int32_t m_screen_h;

    float m_camera_w;
    float m_camera_h;

    Color m_clear_color {};
    std::vector<REntity> m_render_entities;
    std::vector<RSortEntry> m_sort_entries;

    std::unique_ptr<RSoftwareBackend> m_backend;


    friend class RSoftwareBackend;
};