#include <glad/glad.h>
#include <SDL3/SDL.h>

#include "shader.h"


using namespace std;



int main(int argc, char* argv[]) {

    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);

    SDL_Window *window = SDL_CreateWindow("OpenGL Demo", 800, 600, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);
    SDL_Renderer *renderer = SDL_CreateRenderer(window, "opengl", 0);
    SDL_RendererInfo info;
    SDL_GetRendererInfo(renderer, &info);
    SDL_Log("%s", info.name);

    SDL_GLContext context = SDL_GL_GetCurrentContext();
    if (context == NULL)
        SDL_LogError(0, "Failed to initialize OpenGL context: %s", SDL_GetError());

    if (!gladLoadGLLoader((GLADloadproc)SDL_GL_GetProcAddress))
        SDL_LogError(0, "Failed to initialize GALD!");

    glViewport(0, 0, 800, 600);

    bool running = true;
    SDL_Event event;

    float vertices[] = {
        // Positions        // Colour         // Texture coord
        -0.5f,  0.5f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, // top-left
         0.5f,  0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, // top-right
         0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, // bottom-right
        -0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, // bottom-left
    };

    unsigned int indices[] = {
        0, 1, 2,
        0, 2, 3
    };

    unsigned int VBO;
    glGenBuffers(1, &VBO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);



    // Shader Program
    Shader shader("../src/sdl-shader-opengl/shader.vert", "../src/sdl-shader-opengl/shader.frag");

    // VAOs
    unsigned int VAO;
    glGenVertexArrays(1, &VAO);

    glBindVertexArray(VAO);

    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8*sizeof(float), (void *)0);
    glEnableVertexAttribArray(0);

    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8*sizeof(float), (void *)(3*sizeof(float)));
    glEnableVertexAttribArray(1);

    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8*sizeof(float), (void *)(6*sizeof(float)));
    glEnableVertexAttribArray(2);

    // EBOs
    unsigned int EBO;
    glGenBuffers(1, &EBO);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

    SDL_Texture *tex = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA32, SDL_TEXTUREACCESS_TARGET, 800, 600);
    GLint tex_id = SDL_GetNumberProperty(SDL_GetTextureProperties(tex), SDL_PROP_TEXTURE_OPENGL_TEXTURE_NUMBER, 0);

    SDL_FRect rect = {0, 0, 100, 100};

    while (running) {

        while (SDL_PollEvent(&event)) {
            if (event.type == SDL_EVENT_QUIT)
                running = false;
        }

        SDL_SetRenderTarget(renderer, tex);
        SDL_SetRenderDrawColor(renderer, 255, 255, 0, 255);
        SDL_RenderClear(renderer);
        SDL_SetRenderDrawColor(renderer, 0, 255, 0, 255);
        SDL_RenderFillRect(renderer, &rect);
        SDL_SetRenderTarget(renderer, NULL);

        SDL_FlushRenderer(renderer);

        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        shader.use();
        glBindTexture(GL_TEXTURE_2D, tex_id);
        glBindVertexArray(VAO);
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
        glBindVertexArray(0);

        SDL_GL_SwapWindow(window);
    }

    return 0;
}