extern crate smithay_client_toolkit as sctk;

use calloop::{timer::Timer, EventLoop};
use clap::Parser;
use sctk::reexports::client::protocol::{wl_shm, wl_surface};
use sctk::shm::AutoMemPool;
use sctk::window::{Event as WEvent, FallbackFrame};
use svg::node::element::path::Data as PathData;

mod clock;
mod config;
mod svg_clock;

use clock::get_current_hour_name;
use config::{get_config, Config};
use svg_clock::{cache_hour_name_paths, gen_svg, svg_to_usvg};

#[derive(Parser, Debug)]
#[clap(author, version, about, long_about = None)]
struct Args {
    /// Print the current hour’s name and exit
    #[clap(short, long)]
    now: bool,

    /// Use FILE as the configuration file
    #[clap(short, long, value_name = "FILE")]
    config: Option<String>,
}

sctk::default_environment!(SeasonalClock, desktop);

fn main() {
    let args = Args::parse();

    if args.now {
        println!("{}", get_current_hour_name());
        std::process::exit(0);
    }

    let config = get_config(args.config);

    run_windowed(&config);
}

fn run_windowed(config: &Option<Config>) {
    let (env, display, queue) = sctk::new_default_environment!(SeasonalClock, desktop)
        .expect("Unable to connect to a Wayland compositor");

    let surface = env
        .create_surface_with_scale_callback(|dpi, _surface, _dispatch_data| {
            println!("dpi changed to {}", dpi);
        })
        .detach();

    let mut next_action = None::<WEvent>;

    let mut window = env
        .create_window::<FallbackFrame, _>(
            surface,
            None,
            (100, 100),
            move |evt, mut dispatch_data| {
                let next_action = dispatch_data.get::<Option<WEvent>>().unwrap();
                let replace = matches!(
                    (&evt, &*next_action),
                    (_, &None)
                        | (_, &Some(WEvent::Refresh))
                        | (&WEvent::Configure { .. }, &Some(WEvent::Configure { .. }))
                        | (&WEvent::Close, _)
                );

                if replace {
                    *next_action = Some(evt);
                }
            },
        )
        .expect("Failed to create a window !");

    window.set_title("Seasonal Hours Clock".to_string());

    let mut pool = env
        .create_auto_pool()
        .expect("Failed to create the memory pool.");
    let mut need_redraw = false;
    let mut dimensions = (700, 700);

    let hour_name_path_cache = cache_hour_name_paths();

    if !env.get_shell().unwrap().needs_configure() {
        redraw(
            &mut pool,
            window.surface(),
            dimensions,
            config,
            &hour_name_path_cache,
        )
        .expect("Failed to draw");
        window.refresh()
    }

    let mut event_loop = EventLoop::<Option<WEvent>>::try_new().unwrap();
    let handle = event_loop.handle();
    let source = Timer::new().expect("Failed to create timer event source!");
    let timer_handle = source.handle();
    timer_handle.add_timeout(std::time::Duration::from_secs(1), "");

    handle
        .insert_source(source, |_, timer_handle, event| {
            timer_handle.add_timeout(std::time::Duration::from_secs(1), "");
            if event.is_none() {
                *event = Some(sctk::window::Event::Refresh);
            }
        })
        .unwrap();

    sctk::WaylandSource::new(queue)
        .quick_insert(handle)
        .unwrap();

    loop {
        // Update every second
        match next_action.take() {
            Some(WEvent::Close) => break,
            Some(WEvent::Refresh) => {
                redraw(
                    &mut pool,
                    window.surface(),
                    dimensions,
                    config,
                    &hour_name_path_cache,
                )
                .expect("Failed to draw");
                window.refresh();
                window.surface().commit();
            }
            Some(WEvent::Configure {
                new_size,
                states: _,
            }) => {
                if let Some((w, h)) = new_size {
                    if dimensions != (w, h) {
                        dimensions = (w, h);
                    }
                }
                window.resize(dimensions.0, dimensions.1);
                window.refresh();
                need_redraw = true;
            }
            None => {}
        }

        if need_redraw {
            need_redraw = false;

            redraw(
                &mut pool,
                window.surface(),
                dimensions,
                config,
                &hour_name_path_cache,
            )
            .expect("Failed to draw")
        }

        if let Err(e) = display.flush() {
            if e.kind() != ::std::io::ErrorKind::WouldBlock {
                eprintln!("Error while trying to flush the wayland socket: {:?}", e);
            }
        }

        event_loop.dispatch(None, &mut next_action).unwrap();
    }
}

fn redraw(
    pool: &mut AutoMemPool,
    surface: &wl_surface::WlSurface,
    (buf_x, buf_y): (u32, u32),
    config: &Option<Config>,
    hour_name_path_cache: &[(PathData, PathData); 24],
) -> Result<(), ::std::io::Error> {
    let document = gen_svg(config, hour_name_path_cache);
    let svg_tree = svg_to_usvg(document);

    let (canvas, new_buffer) = pool.buffer(
        buf_x as i32,
        buf_y as i32,
        4 * buf_x as i32,
        wl_shm::Format::Argb8888,
    )?;

    let image_size = ::std::cmp::min(buf_x, buf_y);
    let move_x = (buf_x - image_size) as f32 / 2.0;
    let move_y = (buf_y - image_size) as f32 / 2.0;
    let mut pixmap = tiny_skia::Pixmap::new(buf_x, buf_y).unwrap();
    // pre-fill the pixmap with our background color so we don’t have a white strip at the edges
    pixmap.fill(
        tiny_skia::Color::from_rgba(19f32 / 255f32, 17f32 / 255f32, 30f32 / 255f32, 1f32).unwrap(),
    );
    resvg::render(
        &svg_tree,
        usvg::FitTo::Size(image_size, image_size),
        tiny_skia::Transform::from_translate(move_x, move_y),
        pixmap.as_mut(),
    )
    .unwrap();
    // We do not have anything to draw yet, so draw an empty surface
    for (dst_pixel, src_pixel) in canvas.chunks_exact_mut(4).zip(pixmap.pixels()) {
        let r = src_pixel.red() as u32;
        let g = src_pixel.green() as u32;
        let b = src_pixel.blue() as u32;
        let a = src_pixel.alpha() as u32;

        let r = ::std::cmp::min(0xFF, (0xFF * (0xFF - a) + a * r) / 0xFF);
        let g = ::std::cmp::min(0xFF, (0xFF * (0xFF - a) + a * g) / 0xFF);
        let b = ::std::cmp::min(0xFF, (0xFF * (0xFF - a) + a * b) / 0xFF);

        let pixel: [u8; 4] = ((0xFF << 24) + (r << 16) + (g << 8) + b).to_ne_bytes();

        dst_pixel[0] = pixel[0];
        dst_pixel[1] = pixel[1];
        dst_pixel[2] = pixel[2];
        dst_pixel[3] = pixel[3];
    }

    surface.attach(Some(&new_buffer), 0, 0);

    if surface.as_ref().version() >= 4 {
        surface.damage_buffer(0, 0, buf_x as i32, buf_y as i32);
    } else {
        surface.damage(0, 0, buf_x as i32, buf_y as i32);
    }

    surface.commit();

    Ok(())
}