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


SDL_Surface *
ui_label_outline(
        TTF_Font *font,
        const SDL_Color *fg_color,
        const SDL_Color *bg_color,
        const int outline,
        const char text[]) 
{
    const int original_outline = TTF_GetFontOutline(font);
    TTF_SetFontOutline(font, outline);
    SDL_Surface *bg_surface = TTF_RenderText_Blended(font, text, *bg_color);

    TTF_SetFontOutline(font, 0);
    SDL_Surface *fg_surface = TTF_RenderText_Blended(font, text, *fg_color);

    SDL_Rect rect = {outline, outline, fg_surface->w, fg_surface->h};
    SDL_SetSurfaceBlendMode(fg_surface, SDL_BLENDMODE_BLEND);
    SDL_BlitSurface(fg_surface, NULL, bg_surface, &rect);
    SDL_FreeSurface(fg_surface);
    TTF_SetFontOutline(font, original_outline);

    return bg_surface;
}


void
init_all() {
    if( SDL_Init(SDL_INIT_EVERYTHING) < 0 ) {
        printf("SDL: init %s\n", SDL_GetError());
        exit(2);
    }
    atexit(SDL_Quit);

    if( TTF_Init() < 0 ) {
        printf("SDLTTF: init %s\n", TTF_GetError());
        exit(2);
    }
    atexit(TTF_Quit);
}


bool handle_input(SDL_Event * event) {
        while (SDL_PollEvent(event)) 
            if (( event->type == SDL_QUIT ) || 
                ( event->type == SDL_KEYDOWN && event->key.keysym.sym == SDLK_q ))
                return false;
        return true;
}


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

    const unsigned int SCREEN_WIDTH  = 800;
    const unsigned int SCREEN_HEIGHT = 600;
    const char fontname[] = "PressStart2P.ttf";
    const uint8_t fontsize = 16;
    const uint8_t outline = 3; 

    time_t rawtime;
    struct tm *timeinfo;

    int w, h;
    bool running = true;

    init_all();

    SDL_Window  * window = SDL_CreateWindow("Outline", 
            SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
            SCREEN_WIDTH, SCREEN_HEIGHT,
            SDL_WINDOW_SHOWN);

    SDL_Renderer * renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);

    TTF_Font *monofont = TTF_OpenFont(fontname, fontsize);
    if(!monofont) {
        printf("SDL: OpenFont %s\n", TTF_GetError());
        exit(2);
    }

    SDL_Color Yellow = {255, 255, 0};
    SDL_Color Black = {0, 0, 0};

    SDL_Event event;
    SDL_SetRenderDrawColor( renderer, 255, 255, 255, SDL_ALPHA_OPAQUE );
    SDL_Texture * label_texture = NULL;
    SDL_Surface * label = NULL;
    SDL_Rect rect;
    char timestr[25];
    while(running) {
        SDL_RenderClear( renderer );

        running = handle_input(&event);

        time(&rawtime);
        timeinfo = localtime(&rawtime);
        
        snprintf(timestr, 25, "%s", asctime(timeinfo));
        label = ui_label_outline(monofont, &Yellow, &Black, 3, timestr);
        label_texture = SDL_CreateTextureFromSurface(renderer, label);
        SDL_QueryTexture(label_texture, NULL, NULL, &w, &h);
        rect = (SDL_Rect){ (SCREEN_WIDTH-w)/2, (SCREEN_HEIGHT-h)/2, w, h };

        SDL_RenderCopy(renderer, label_texture, NULL, &rect);
        SDL_RenderPresent(renderer);

        // SDL_FreeSurface(label); label = NULL;
        // SDL_DestroyTexture(label_texture); label_texture = NULL;

        SDL_Delay(100);
    }

    TTF_CloseFont(monofont);
    SDL_DestroyRenderer(renderer); renderer = NULL;
    SDL_DestroyWindow(window); window = NULL;

    return 0;
}