#include <format>
#include <stdexcept>

#define SDL_MAIN_USE_CALLBACKS 1
#include "SDL3/SDL.h"
#include "SDL3/SDL_main.h"

class Application
{
    SDL_Window *window = nullptr;
    SDL_Renderer *renderer = nullptr;

public:
    Application(int argc, char **argv)
    {
        SDL_SetAppMetadata("Example Renderer Clear", "1.0", "com.example.renderer-clear");

        if (!SDL_Init(SDL_INIT_VIDEO))
        {
            auto message = std::format("Couldn't initialize SDL: {}", SDL_GetError());
            throw std::runtime_error(message);
        }

        if (!SDL_CreateWindowAndRenderer("examples/renderer/clear", 640, 480, SDL_WINDOW_RESIZABLE, &window, &renderer))
        {
            auto message = std::format("Couldn't create window/renderer: {}", SDL_GetError());
            throw std::runtime_error(message);
        }

        SDL_SetRenderLogicalPresentation(renderer, 640, 480, SDL_LOGICAL_PRESENTATION_LETTERBOX);
    }

    SDL_AppResult processEvent(SDL_Event *event) noexcept
    {
        if (event->type == SDL_EVENT_QUIT)
        {
            return SDL_APP_SUCCESS;
        }

        return SDL_APP_CONTINUE;
    }

    SDL_AppResult renderFrame() noexcept
    {
        const double now = ((double)SDL_GetTicks()) / 1000.0;
        const float red = (float) (0.5 + 0.5 * SDL_sin(now));
        const float green = (float) (0.5 + 0.5 * SDL_sin(now + SDL_PI_D * 2 / 3));
        const float blue = (float) (0.5 + 0.5 * SDL_sin(now + SDL_PI_D * 4 / 3));
        SDL_SetRenderDrawColorFloat(renderer, red, green, blue, SDL_ALPHA_OPAQUE_FLOAT);

        SDL_RenderClear(renderer);

        SDL_RenderPresent(renderer);

        return SDL_APP_CONTINUE;
    }
};

extern "C"
{

SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[])
{
    try
    {
        *appstate = nullptr;
        *appstate = reinterpret_cast<void *>(new Application(argc, argv));

        return SDL_APP_CONTINUE;
    }
    catch (...)
    {
        return SDL_APP_FAILURE;
    }
}

SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event)
{
    return reinterpret_cast<Application *>(appstate)->processEvent(event);
}

SDL_AppResult SDL_AppIterate(void *appstate)
{
    return reinterpret_cast<Application *>(appstate)->renderFrame();
}

/* This function runs once at shutdown. */
void SDL_AppQuit(void *appstate, SDL_AppResult result)
{
    delete reinterpret_cast<Application *>(appstate);
}

}