#include <SDL2/SDL.h>    
#include <SDL2/SDL2_framerate.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdint.h>

const int WINDOW_WIDTH  = 1024;
const int WINDOW_HEIGHT = 768;
const float scale_x = (float)WINDOW_WIDTH/(float)0xfff;
const float scale_y = (float)WINDOW_HEIGHT/(float)0x7ff;


int main( int argc, char **argv )
{
    SDL_Init( SDL_INIT_EVERYTHING );
    atexit(SDL_Quit);

    SDL_Window *window = SDL_CreateWindow( "Frames",
            SDL_WINDOWPOS_UNDEFINED,
            SDL_WINDOWPOS_UNDEFINED,
            WINDOW_WIDTH, 
            WINDOW_HEIGHT, 
            SDL_WINDOW_SHOWN
            );

    SDL_Renderer *renderer = SDL_CreateRenderer( window, -1, SDL_RENDERER_ACCELERATED);
    SDL_RenderSetLogicalSize(renderer, WINDOW_WIDTH, WINDOW_HEIGHT);
    SDL_SetRenderDrawBlendMode(renderer, SDL_BLENDMODE_BLEND);
    SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "0");

    FPSmanager fpsManager;
    SDL_initFramerate( &fpsManager );
    SDL_setFramerate( &fpsManager, 60);
    bool bRunning = true;

    int frameCount = 0;
    Uint32 time = SDL_GetTicks();
    int squares = 1;

    int pos, color;
    uint8_t w, h, r, g, b, a;
    uint16_t x, y;

    SDL_Rect rect;

    while ( bRunning )
    {

        srand(0);
        SDL_Event ev;

        while ( SDL_PollEvent( & ev ))  // Check event queue.
        {
            switch( ev.type )
            {
                case SDL_QUIT: // when window is closed
                    bRunning = false;
                    break;
                case SDL_KEYDOWN:
                    switch ( ev.key.keysym.sym )
                    {
                        case SDLK_1:
                            squares = 1;
                            break;
                        case SDLK_UP:
                            squares *= 2;
                            break;
                        case SDLK_DOWN:
                            squares /= 2;
                            break;
                        case SDLK_q:
                            bRunning = false;
                            break;
                    }
                    break;
            }
        }

        SDL_SetRenderDrawColor (renderer, 0, 0, 0, SDL_ALPHA_OPAQUE);
        SDL_RenderClear (renderer);
        for(int i = 0; i < squares; i++) {
            color = rand();
            r = (color) & 0xff;
            g = (color >> 8) & 0xff;
            b = (color >> 16) & 0xff;
            a = (color >> 24) & 0xff;
            SDL_SetRenderDrawColor (renderer, r, g, b, a);
            
            pos = rand();
            rect.x = (((pos)       & 0x7ff) << 1) * scale_x;    // 11 bits * 2
            rect.y = (((pos >> 11) & 0x3ff) << 1) * scale_y;    // 10 bits * 2
            rect.w = ((pos >> 21) & 0x1f);                      // 5 bits 
            rect.h = ((pos >> 27) & 0x1f);                      // 5 bits
            SDL_RenderFillRect(renderer, &rect);
        }

        if ( SDL_GetTicks() - time > 1000 )
        {
            fprintf(stdout, "FPS %8d - Rects %8d\r", frameCount, squares);
            fflush(stdout);
            frameCount = 0;
            time = SDL_GetTicks();
        }
        else {
            ++frameCount;
        }
        SDL_RenderPresent(renderer);
        SDL_framerateDelay(&fpsManager);

    }
    
    SDL_DestroyRenderer(renderer); renderer = NULL;
    SDL_DestroyWindow(window); window = NULL;
    return 0;
}