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

int* g_framebuffer;
SDL_Window* g_SDLWindow;
SDL_Renderer* g_SDLRenderer;
SDL_Texture* g_SDLTexture;

static int g_Done;
const int WINDOW_WIDTH = 1920 / 2;
const int WINDOW_HEIGHT = 1080 / 2;

bool update() {
    SDL_Event e;
    if (SDL_PollEvent(&e)) {
        if (e.type == SDL_EVENT_QUIT)
            return false;
        if (e.type == SDL_EVENT_KEY_UP && e.key.key == SDLK_ESCAPE)
            return false;
    }

    char* pix;
    int pitch;

    SDL_LockTexture(g_SDLTexture, NULL, (void**)&pix, &pitch);
    for (int i = 0, sp = 0, dp = 0; i < WINDOW_HEIGHT; i++, dp += WINDOW_WIDTH, sp += pitch) {
        memcpy(pix + sp, g_framebuffer + dp, WINDOW_WIDTH * 4);
    }
    
    SDL_UnlockTexture(g_SDLTexture);
    SDL_RenderTexture(g_SDLRenderer, g_SDLTexture, NULL, NULL);
    SDL_RenderPresent(g_SDLRenderer);
    SDL_Delay(1);
    return true;
}

void render(u64 aTicks) {
    for (int i = 0, c = 0; i < WINDOW_HEIGHT; i++) {
        for (int j = 0; j < WINDOW_WIDTH; j++, c++) {
            g_framebuffer[c] = (int)(i * i + j * j + aTicks) | 0xff000000;
        }
    }
}

void loop() {
    if (!update()) {
        g_Done = 1;
    } else {
        render(SDL_GetTicks());
    }
}

int main() {
    if (!SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS)) {
        return -1;
    }

    g_framebuffer = new int[WINDOW_WIDTH * WINDOW_HEIGHT];
    g_SDLWindow = SDL_CreateWindow("test", WINDOW_WIDTH, WINDOW_HEIGHT, 0);
    g_SDLRenderer = SDL_CreateRenderer(g_SDLWindow, NULL);
    g_SDLTexture = SDL_CreateTexture(g_SDLRenderer, SDL_PIXELFORMAT_ABGR8888, SDL_TEXTUREACCESS_STREAMING, WINDOW_WIDTH, WINDOW_HEIGHT);
    
    if (!g_framebuffer || !g_SDLWindow || !g_SDLRenderer || ! g_SDLTexture) {
        return -1;
    }

    g_Done = 0;

    while (!g_Done) {
        loop();
    }

    SDL_DestroyTexture(g_SDLTexture);
    SDL_DestroyRenderer(g_SDLRenderer);
    SDL_DestroyWindow(g_SDLWindow);
    SDL_Quit();

    return 0;
}