extern crate smithay_client_toolkit as sctk;

use std::time::SystemTime;

use chrono::prelude::Local;
use chrono::Timelike;
use sctk::reexports::client::protocol::{wl_shm, wl_surface};
use sctk::shm::AutoMemPool;
use sctk::window::{Event as WEvent, FallbackFrame};
use svg::node::element::{Group, Line, Rectangle, Style, Text};
use svg::node::Text as TextNode;
use svg::Document;

sctk::default_environment!(SeasonalClock, desktop);

fn seconds_to_degrees(seconds: i32) -> f32 {
    seconds as f32 * 360.0 / 86400.0
}

fn time_to_degrees(timestamp: i32, // should be time/timestamp
) -> f32 {
    seconds_to_degrees(timestamp)
}

fn gen_svg() -> Document {
    // These should be calculated
    let local_timestamp = Local::now();
    let local_time = local_timestamp.time().num_seconds_from_midnight() as i32;

    // TODO: These should be calculated instead of hardcoded
    let image_width = 700u32;
    let local_hour_font_size = 16.5;
    let hour_name_font_size = 13.37699;
    let outer_r = (image_width as f32) / 2.0 - 3.0 * hour_name_font_size;
    let ring_width = hour_name_font_size * 3.0;
    let border = Rectangle::new()
        .set("x", 0i32)
        .set("y", 0i32)
        .set("width", 700i32)
        .set("height", 700i32)
        .set("id", "border");
    let stylesheet = Style::new(
        "\
        #border {stroke: none; fill: rgb(19, 17, 30); }
        .local-hour {stroke: none; fill: rgb(238, 187, 85);}
        .dial {stroke-width: 2px; stroke: rgb(238, 187, 85);}",
    );
    let mut local_clock = Group::new().set("id", "local-clock");

    for hour in 0i32..24 {
        let hour_str = match hour {
            0 => "Midnight".to_string(),
            12 => "Noon".to_string(),
            _ => hour.to_string(),
        };
        let rotation = hour * 15;
        let hour_name = TextNode::new(hour_str);
        let hour_node = Text::new()
            .set("class", "local-hour")
            .set("transform", format!("rotate({}, 350, 350)", 180 + rotation))
            .set("x", (image_width as f32) / 2.0)
            .set(
                "y",
                (image_width as f32) / 2.0 - outer_r - local_hour_font_size / 2.0,
            )
            .set("text-anchor", "middle")
            .set("font-size", local_hour_font_size as f32)
            .add(hour_name);
        local_clock = local_clock.add(hour_node);
    }

    let dial = Line::new()
        .set("id", "dial")
        .set("class", "dial")
        .set(
            "transform",
            format!(
                "rotate({}, {}, {})",
                time_to_degrees(local_time),
                image_width / 2,
                image_width / 2
            ),
        )
        .set("x1", image_width / 2)
        .set("y1", image_width as f32 / 2.0 + outer_r * 0.5)
        .set("x2", image_width / 2)
        .set(
            "y2",
            image_width as f32 / 2.0 + outer_r - ring_width + hour_name_font_size,
        );

    Document::new()
        .set("viewBox", (0i32, 0i32, 700i32, 700i32))
        .set("width", 700i32)
        .set("height", 700i32)
        .set("xmlns:xlink", "http://www.w3.org/1999/xlink")
        .add(stylesheet)
        .add(border)
        .add(local_clock)
        .add(dial)
}

fn main() {
    let (env, display, mut 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);

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

    let now = SystemTime::now();
    let mut last_elapsed = 0;

    loop {
        // Update every second
        // TODO: There’s probably a better way to do this…
        match now.elapsed() {
            Ok(elapsed) => {
                let new_elapsed = elapsed.as_secs();

                if new_elapsed != last_elapsed {
                    need_redraw = true;
                    last_elapsed = new_elapsed;
                }
            }
            Err(e) => {
                println!("Error: {:?}", e);
            }
        }
        match next_action.take() {
            Some(WEvent::Close) => break,
            Some(WEvent::Refresh) => {
                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).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);
            }
        }

        if let Some(guard) = queue.prepare_read() {
            if let Err(e) = guard.read_events() {
                if e.kind() != ::std::io::ErrorKind::WouldBlock {
                    eprintln!(
                        "Error while trying to read from the wayland socked: {:?}",
                        e
                    );
                }
            }
        }

        queue
            .dispatch_pending(&mut next_action, |_, _, _| {})
            .expect("Failed to dispatch all messages.");
    }
}

fn redraw(
    pool: &mut AutoMemPool,
    surface: &wl_surface::WlSurface,
    (buf_x, buf_y): (u32, u32),
) -> Result<(), ::std::io::Error> {
    let document = gen_svg();

    let bytes = document.to_string();
    let mut opt = usvg::Options::default();
    opt.fontdb.load_system_fonts();
    opt.font_family = "Liberation Serif".to_string();
    let svg_tree = usvg::Tree::from_str(&bytes, &opt.to_ref()).unwrap();

    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();
    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(())
}