extern crate sdl2;

use sdl2::event::Event;
use sdl2::keyboard::Keycode;
use std::collections::HashSet;
use std::time::Duration;

pub fn main() -> Result<(), String> {
    let sdl_context = sdl2::init()?;
    let video_subsystem = sdl_context.video()?;

    let _window = video_subsystem.window("Mouse", 800, 600)
        .position_centered()
        .build()
        .map_err(|e| e.to_string())?;

    let mut events = sdl_context.event_pump()?;

    let mut prev_buttons = HashSet::new();

    'running: loop {
        for event in events.poll_iter() {
            match event {
                Event::KeyDown { keycode: Some(Keycode::Escape), .. } |
                Event::Quit { .. } => break 'running,
                _ => {}
            }
        }

        // get a mouse state
        let state = events.mouse_state();

        // Create a set of pressed Keys.
        let buttons = state.pressed_mouse_buttons().collect();

        // Get the difference between the new and old sets.
        let new_buttons = &buttons - &prev_buttons;
        let old_buttons = &prev_buttons - &buttons;

        if !new_buttons.is_empty() || !old_buttons.is_empty() {
            println!("X = {:?}, Y = {:?} : {:?} -> {:?}", state.x(), state.y(),  new_buttons, old_buttons);
        }

        prev_buttons = buttons;

        std::thread::sleep(Duration::from_millis(100));
    }

    Ok(())
}