#include <SDL2/SDL.h>
#include <stdbool.h>
#include <stdint.h>


struct game {
    bool              gameover;
    int               screen_width;
    int               screen_height;
    uint8_t           r;
    uint8_t           g;
    uint8_t           b;
    uint32_t          argb;
    SDL_Window      * window;
    SDL_Renderer    * renderer;
    SDL_Surface     * screen;
    SDL_Event       * event;
};

struct game *   game_init           (void);
void            game_handle_input   (struct game * game);
void            game_update         (struct game * game);
void            game_render         (struct game * game);
void            game_destroy        (struct game * game);


int main(int argc, char *argv[])
{
    struct game * game = game_init();

    while(!game->gameover)
    {
        game_handle_input(game);
        game_update(game);
        game_render(game);
    }

    game_destroy(game);

    SDL_Log("Exiting\n");
    return 0;
}


struct game *
game_init(void)
{
    int retval;

    struct game *game = malloc(sizeof *game);

    game->gameover = false;
    game->screen_width = 1280;
    game->screen_height = 720;
    game->r = 0;
    game->g = 0;
    game->b = 0;
    game->argb = 0;

    retval = SDL_Init(SDL_INIT_EVERYTHING);
    if(retval < 0)
    {
        SDL_LogError (SDL_LOG_CATEGORY_APPLICATION, "SDL_Init: %s\n", SDL_GetError());
        exit(EXIT_FAILURE);
    }
    atexit(SDL_Quit);

    game->window = SDL_CreateWindow("Game: Init",
            SDL_WINDOWPOS_UNDEFINED,
            SDL_WINDOWPOS_UNDEFINED,
            game->screen_width,
            game->screen_height,
            0);
    if(game->window == NULL)
    {
        SDL_LogError (SDL_LOG_CATEGORY_APPLICATION, "SDL_CreateWindow: %s\n", SDL_GetError());
        exit(EXIT_FAILURE);
    }

    game->renderer = SDL_CreateRenderer(game->window, -1, SDL_RENDERER_ACCELERATED);
    if(game->renderer == NULL)
    {
        SDL_LogError (SDL_LOG_CATEGORY_APPLICATION, "SDL_CreateRenderer: %s\n", SDL_GetError());
        exit(EXIT_FAILURE);
    }

    SDL_RendererInfo info;
    SDL_GetRendererInfo(game->renderer, &info );
    SDL_Log("Renderer Name: %s\n", info.name);

    SDL_Log("Texture formats: \n");
    for (size_t i = 0; i < info.num_texture_formats; i++) {
        SDL_Log("%s\n", SDL_GetPixelFormatName(info.texture_formats[i]));
    }

    game->event = malloc(sizeof (game->event));

    return game;
}

void
game_handle_input(struct game * game)
{
    while(SDL_PollEvent(game->event))
    {
        switch(game->event->type)
        {
            case SDL_QUIT: game->gameover = true; break;
            case SDL_KEYDOWN: switch(game->event->key.keysym.sym)
            {
                case SDLK_ESCAPE: game->gameover = true; break;
            }
        }
    }
}


void
game_update(struct game *game)
{
    game->r = (game->argb)       & 0xff;
    game->g = (game->argb >> 8)  & 0xff;
    game->b = (game->argb >> 16) & 0xff;
    game->argb++;
}

void
game_render(struct game *game)
{
    int retval;
    retval = SDL_SetRenderDrawColor (game->renderer, game->r, game->g, game->b, 255);
    if(retval < 0)
    {
        SDL_Log("SDL_SetRenderDrawColor: %s\n", SDL_GetError());
        exit(EXIT_FAILURE);
    }
    retval = SDL_RenderClear(game->renderer);
    if(retval < 0)
    {
        SDL_Log("SDL_RenderClear: %s\n", SDL_GetError());
        exit(EXIT_FAILURE);
    }
    SDL_RenderPresent(game->renderer);
}



void
game_destroy(struct game *game)
{
    if(game->renderer != NULL)
    {
        SDL_Log("Destroying renderer()\n");
        SDL_DestroyRenderer(game->renderer);
        game->renderer = NULL;
    }

    if(game->window != NULL)
    {
        SDL_Log("Destroying main window()\n");
        SDL_DestroyWindow (game->window);
        game->window = NULL;
    }

    if(game != NULL)
    {
        SDL_Log("Destroying game\n");
        free(game);
    }
}