extern crate sdl2;

use sdl2::pixels::Color;
use sdl2::event::Event;
use sdl2::rect::Rect;
use sdl2::keyboard::Keycode;
use sdl2::render::Renderer;

use std::time::Duration;

const SCR_WIDTH: u32 = 800;
const SCR_HEIGHT: u32 = 800;

const BLACK: Color = Color::RGB(0, 0, 0);
const WHITE: Color = Color::RGB(255, 255, 255);

const SQR_SIZE: u32 = SCR_WIDTH / 8;

fn main() {
    let context = sdl2::init().unwrap();
    let video = context.video().unwrap();

    let window  = match video
        .window("Chess", SCR_WIDTH, SCR_HEIGHT)
        .position_centered()
        .opengl()
        .build() {
            Ok(window) => window,
            Err(err)   => panic!("failed to create window: {}", err)
        };

    let mut renderer = match window
        .renderer()
        .build() {
            Ok(renderer) => renderer,
            Err(err) => panic!("failed to create renderer: {}", err)
        };

    let mut event_pump = context.event_pump().unwrap();

    'main_loop: loop {
        draw_grid(&mut renderer);

        for event in event_pump.poll_iter() {
            // if esc or q pressed, exit main loop
            // (consequently ending the program)
            match event {
                Event::Quit {..} |
                    Event::KeyDown { keycode: Some(Keycode::Q), .. } => {
                        break 'main_loop
                    },
                _ => {}
            }

            // draw frames (swap buffers & company)
            renderer.present();
            // ::std::thread::sleep(Duration::new(0, 1_000_000_000u32 / 60));
        }
    }
}


fn draw_grid(renderer: &mut Renderer) {
    renderer.set_draw_color(BLACK);
    renderer.clear();

    // draw squares (only the white ones since the black ones are part of background)
    renderer.set_draw_color(WHITE);
    let a = Rect::new(10, 10, 10, 10);
    let _ = renderer.fill_rect(a);
    for i in (0..=(SCR_WIDTH - SQR_SIZE)).step_by(SQR_SIZE as usize) {

        let sqr = Rect::new(i as i32, i as i32, i + SQR_SIZE, i + SQR_SIZE);
        let _    = renderer.fill_rect(sqr);
   }
}