use std::thread;
use std::time::Duration;

extern crate rand;
use rand::seq::SliceRandom;
use rand::Rng;

extern crate sdl2;
use sdl2::event::Event;
use sdl2::gfx::primitives::DrawRenderer;
use sdl2::pixels::Color;

#[cfg(target_os = "emscripten")]
pub mod emscripten;

fn find_origin() -> (i16, i16) {
    let mut rng = rand::thread_rng();
    (rng.gen_range(100..400), rng.gen_range(100..400))
}

struct Line {
    x1: i16,
    y1: i16,
    x2: i16,
    y2: i16,
}

struct Pixel {
    x: i16,
    y: i16,
}

fn main() {
    let context = sdl2::init().unwrap();
    let video = context.video().unwrap();
    let (height, width) = (500, 500);
    let window = video.window("web", height, width).opengl().build().unwrap();
    let mut canvas = window.into_canvas().build().unwrap();
    let mut events = context.event_pump().unwrap();

    canvas.set_draw_color(Color::RGB(0, 0, 0));
    canvas.clear();
    canvas.present();

    let (x, y) = find_origin();
    let mut lines = Vec::new();
    for i in (0..(height as i16 + 1)).step_by(50) {
        lines.push(Line {
            x1: i,
            y1: 0,
            x2: x,
            y2: y,
        });
        lines.push(Line {
            x1: i,
            y1: height as i16,
            x2: x,
            y2: y,
        });
        lines.push(Line {
            x1: 0,
            y1: i,
            x2: x,
            y2: y,
        });
        lines.push(Line {
            x1: width as i16,
            y1: i,
            x2: x,
            y2: y,
        });
    }

    let mut rng = rand::thread_rng();
    lines.shuffle(&mut rng);

    let a = rng.gen_range(-7.0..7.0);
    let b = rng.gen_range(-7.0..7.0);

    let mut pixels = Vec::new();
    for i in (1000..200000).step_by(10) {
        let i = i as f64 * 0.001;
        let x = (a + b * i) * i.cos() + x as f64;
        let y = (a + b * i) * i.sin() + y as f64;
        pixels.push(Pixel {
            x: x as i16,
            y: y as i16,
        });
    }

    let mut main_loop = || {
        let mut i = 0;
        let mut run = true;
        while run {
            for event in events.poll_iter() {
                if let Event::Quit { .. } = event {
                    run = false
                };
            }

            if i < lines.len() {
                let line = &lines[i];
                canvas
                    .line(
                        line.x1,
                        line.y1,
                        line.x2,
                        line.y2,
                        Color::RGB(255, 255, 255),
                    )
                    .unwrap();
            }
            if i < pixels.len() {
                let pixel = &pixels[i];
                canvas
                    .pixel(pixel.x, pixel.y, Color::RGB(255, 255, 255))
                    .unwrap();
            }

            canvas.present();
            thread::sleep(Duration::from_millis(10));
            i += 1;
        }
    };

    #[cfg(target_os = "emscripten")]
    use emscripten::emscripten;

    #[cfg(target_os = "emscripten")]
    emscripten::set_main_loop_callback(main_loop);

    #[cfg(not(target_os = "emscripten"))]
    main_loop();
}