extern crate smithay_client_toolkit as sctk;

use std::fs;

use calloop::{timer::Timer, EventLoop};
use chrono::prelude::{Local, Utc};
use chrono::TimeZone;
use chrono::Timelike;
use sctk::reexports::client::protocol::{wl_shm, wl_surface};
use sctk::shm::AutoMemPool;
use sctk::window::{Event as WEvent, FallbackFrame};
use serde::Deserialize;
use svg::node::element::path::Data as PathData;
use svg::node::element::{Circle, Group, Line, Path, Rectangle, Style, Text};
use svg::node::Text as TextNode;
use svg::Document;

mod svg_clock;

use svg_clock::{
    cache_hour_name_paths, hour_marker, svg_to_usvg, HOUR_NAMES, HOUR_NAME_FONT_SIZE, IMAGE_WIDTH,
    OUTER_R, RING_WIDTH, UTC_HOUR_FONT_SIZE,
};

sctk::default_environment!(SeasonalClock, desktop);

#[derive(Deserialize, Copy, Clone)]
struct Config {
    latitude: f64,
    longitude: f64,
}

#[derive(Deserialize)]
#[serde(rename_all = "kebab-case")]
struct CompleteConfig {
    seasonal_clock: Config,
}

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 get_range_path(radius: f32, range_name: &str, start_time: i32, end_time: i32) -> Path {
    let start_deg = time_to_degrees(start_time);
    let end_deg = time_to_degrees(end_time);
    let deg_diff = end_deg - start_deg;

    let start_delta_x = radius * start_deg.to_radians().sin();
    let start_delta_y = radius * (1.0 - start_deg.to_radians().cos());
    let end_delta_x = radius * end_deg.to_radians().sin();
    let end_delta_y = radius * (1.0 - end_deg.to_radians().cos());

    let path_data = PathData::new()
        .move_to((IMAGE_WIDTH / 2, IMAGE_WIDTH / 2))
        .line_to((
            IMAGE_WIDTH as f32 / 2.0 - start_delta_x,
            IMAGE_WIDTH as f32 / 2.0 + radius - start_delta_y,
        ))
        .elliptical_arc_to((
            radius,
            radius,
            deg_diff,
            ((start_deg < end_deg) ^ (deg_diff.abs() >= 180.0)) as u8,
            0,
            IMAGE_WIDTH as f32 / 2.0 - end_delta_x,
            IMAGE_WIDTH as f32 / 2.0 + radius - end_delta_y,
        ))
        .close();

    Path::new().set("class", range_name).set("d", path_data)
}

fn get_moon_path(radius: f32, moon_phase: f64) -> Path {
    let handle_x_pos = radius as f64 * 1.34;
    let handle_y_pos = radius * 0.88;
    let min_x = IMAGE_WIDTH as f64 / 2.0 - handle_x_pos;
    let max_x = min_x + 2.0 * handle_x_pos;
    let top_y = IMAGE_WIDTH as f32 / 2.0 - handle_y_pos;
    let bottom_y = IMAGE_WIDTH as f32 / 2.0 + handle_y_pos;

    let h1_x: f64;
    let h2_x: f64;

    if moon_phase < 14.0 {
        h1_x = min_x + 2.0 * handle_x_pos * (1.0 - moon_phase / 14.0);
        h2_x = max_x;
    } else {
        h1_x = min_x;
        h2_x = max_x + 2.0 * handle_x_pos * (1.0 - moon_phase / 14.0)
    }

    let path_data = PathData::new()
        .move_to((IMAGE_WIDTH as f32 / 2.0, IMAGE_WIDTH as f32 / 2.0 - radius))
        .cubic_curve_to((
            h1_x,
            top_y,
            h1_x,
            bottom_y,
            IMAGE_WIDTH as f32 / 2.0,
            IMAGE_WIDTH as f32 / 2.0 + radius,
        ))
        .cubic_curve_to((
            h2_x,
            bottom_y,
            h2_x,
            top_y,
            IMAGE_WIDTH / 2,
            IMAGE_WIDTH as f32 / 2.0 - radius,
        ));
    Path::new().set("class", "moon").set("d", path_data)
}

fn gen_svg(config: &Option<Config>, hour_name_path_cache: &[(PathData, PathData); 24]) -> Document {
    let local_timestamp = Local::now();
    let utc_hour = local_timestamp.with_timezone(&Utc).time().hour();
    let local_hour = local_timestamp.time().hour();
    let local_minute = local_timestamp.time().minute();
    let local_second = local_timestamp.time().second();

    let utc_offset = local_timestamp.offset().local_minus_utc();
    let local_time = local_timestamp.time().num_seconds_from_midnight() as i32;
    let utc_rotation = seconds_to_degrees(utc_offset);

    // Calculate the Moon phase
    let unixtime = suncalc::Timestamp(local_timestamp.timestamp_millis());
    let moon_illumination = suncalc::moon_illumination(unixtime);
    let moon_radius = IMAGE_WIDTH as f32 * 0.071428571;
    let moon_phase = moon_illumination.phase * 28.0;

    let local_hour_font_size = IMAGE_WIDTH as f32 * 0.02357;
    let sun_radius = IMAGE_WIDTH as f32 * 0.0142871;
    let marker_radius = OUTER_R - RING_WIDTH - 2.0 * UTC_HOUR_FONT_SIZE;

    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); }
        .hour path.hour-outline {stroke: rgb(0, 0, 0); stroke-width: 2px;}
        .hour path.hour-name {stroke: none; fill: rgb(238, 187, 85);}
        .hour path.utc {stroke: none; fill: rgb(91, 68, 38);}
        .winter path {fill: rgb(70, 62, 108);}
        .active.winter path.hour-outline {fill: rgb(100, 92, 138);}
        .spring path {fill: rgb(55, 87, 55);}
        .active.spring path.hour-outline {fill: rgb(85, 117, 85);}
        .summer path {fill: rgb(113, 92, 43);}
        .active.summer path.hour-outline {fill: rgb(143, 122, 73);}
        .autumn path {fill: rgb(108, 68, 44);}
        .active.autumn.hour-outline path {fill: rgb(138, 98, 74);}
        .local-hour {stroke: none; fill: rgb(238, 187, 85);}
        .night-time {stroke: none; fill: rgb(19, 17, 30);}
        .blue-hour {stroke: none; fill: rgb(9, 1, 119);}
        .golden-hour {stroke: none; fill: rgb(170, 132, 44);}
        .day-time {stroke: none; fill: rgb(125, 197, 240);}
        .marker {stroke: rgb(19, 17, 30); stroke-width: 2px; fill: none;}
        .moon-background {stroke: rgb(170, 170, 170); stroke-width: 2px; fill: rgb(19, 17, 30);}
        .moon {stroke: none; fill: rgb(170, 170, 170);}
        .sun {stroke: none; fill: rgb(238, 187, 85);}
        .mid-marker {stroke: red;}
        .dial {stroke-width: 2px; stroke: rgb(238, 187, 85);}
        #current-hour rect {stroke: none; fill: rgba(255, 255, 255, 0.5);}
        #current-hour-name {font-weight: bold;}",
    );

    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 mut seasonal_clock = Group::new().set(
        "transform",
        format!(
            "rotate({}, {}, {})",
            utc_rotation,
            IMAGE_WIDTH / 2,
            IMAGE_WIDTH / 2
        ),
    );

    for hour in 0i32..24 {
        seasonal_clock = seasonal_clock.add(hour_marker(
            hour,
            &hour_name_path_cache[hour as usize],
            hour == utc_hour as i32,
        ));
    }

    let daytime_circle = Circle::new()
        .set("class", "day-time")
        .set("cx", IMAGE_WIDTH / 2)
        .set("cy", IMAGE_WIDTH / 2)
        .set("r", marker_radius);

    let day_parts_group: Option<Group> = if config.is_some() {
        let sun_times = suncalc::get_times(
            unixtime,
            config.unwrap().latitude,
            config.unwrap().longitude,
            None,
        );
        let noon = Utc
            .timestamp_millis(sun_times.solar_noon.0)
            .time()
            .num_seconds_from_midnight() as i32;
        let midnight = Utc
            .timestamp_millis(sun_times.nadir.0)
            .time()
            .num_seconds_from_midnight() as i32;
        let morning_golden_end = Utc
            .timestamp_millis(sun_times.golden_hour_end.0)
            .time()
            .num_seconds_from_midnight() as i32;
        let evening_golden_start = Utc
            .timestamp_millis(sun_times.golden_hour.0)
            .time()
            .num_seconds_from_midnight() as i32;
        let sunrise = Utc
            .timestamp_millis(sun_times.sunrise.0)
            .time()
            .num_seconds_from_midnight() as i32;
        let sunset = Utc
            .timestamp_millis(sun_times.sunset.0)
            .time()
            .num_seconds_from_midnight() as i32;
        let dawn = Utc
            .timestamp_millis(sun_times.dawn.0)
            .time()
            .num_seconds_from_midnight() as i32;
        let dusk = Utc
            .timestamp_millis(sun_times.dusk.0)
            .time()
            .num_seconds_from_midnight() as i32;

        let golden_hour_path = get_range_path(
            marker_radius,
            "golden-hour",
            morning_golden_end,
            evening_golden_start,
        );

        let sun_disc = Circle::new()
            .set("class", "sun")
            .set("cx", IMAGE_WIDTH / 2)
            .set("cy", IMAGE_WIDTH as f32 / 2.0 + OUTER_R / 2.0 + sun_radius)
            .set("r", sun_radius)
            .set(
                "transform",
                format!(
                    "rotate({}, {}, {})",
                    time_to_degrees(local_time) - utc_rotation,
                    IMAGE_WIDTH / 2,
                    IMAGE_WIDTH / 2
                ),
            );

        let blue_hour_path = get_range_path(
            marker_radius,
            "blue-hour",
            sunrise, // morning_blue_end
            sunset,  // evening_blue_start
        );

        let nighttime_path = get_range_path(marker_radius, "night-time", dawn, dusk);

        let marker_circle = Circle::new()
            .set("class", "marker")
            .set("cx", IMAGE_WIDTH / 2)
            .set("cy", IMAGE_WIDTH / 2)
            .set("r", marker_radius);

        let noon_marker = Line::new()
            .set("class", "mid-marker")
            .set(
                "transform",
                format!(
                    "rotate({}, {}, {})",
                    time_to_degrees(noon),
                    IMAGE_WIDTH / 2,
                    IMAGE_WIDTH / 2
                ),
            )
            .set("x1", IMAGE_WIDTH / 2)
            .set(
                "y1",
                IMAGE_WIDTH as f32 / 2.0 + marker_radius - sun_radius as f32,
            )
            .set("x2", IMAGE_WIDTH / 2)
            .set("y2", IMAGE_WIDTH as f32 / 2.0 + marker_radius);

        let midnight_marker = Line::new()
            .set("class", "mid-marker")
            .set(
                "transform",
                format!(
                    "rotate({}, {}, {})",
                    time_to_degrees(midnight),
                    IMAGE_WIDTH / 2,
                    IMAGE_WIDTH / 2
                ),
            )
            .set("x1", IMAGE_WIDTH / 2)
            .set(
                "y1",
                IMAGE_WIDTH as f32 / 2.0 + marker_radius - sun_radius as f32,
            )
            .set("x2", IMAGE_WIDTH / 2)
            .set("y2", IMAGE_WIDTH as f32 / 2.0 + marker_radius);

        Some(
            Group::new()
                .set("id", "day-parts")
                .set(
                    "transform",
                    format!(
                        "rotate({}, {}, {})",
                        utc_rotation,
                        IMAGE_WIDTH / 2,
                        IMAGE_WIDTH / 2
                    ),
                )
                .add(daytime_circle)
                .add(golden_hour_path)
                .add(sun_disc)
                .add(blue_hour_path)
                .add(nighttime_path)
                .add(marker_circle)
                .add(noon_marker)
                .add(midnight_marker),
        )
    } else {
        None
    };

    let moon_circle = Circle::new()
        .set("class", "moon-background")
        .set("cx", IMAGE_WIDTH / 2)
        .set("cy", IMAGE_WIDTH / 2)
        .set("r", moon_radius);

    let moon_group = Group::new()
        .set("id", "moon-container")
        .add(moon_circle)
        .add(get_moon_path(moon_radius, moon_phase));

    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,
        );

    let current_box_width = (200f32 / 700f32) * IMAGE_WIDTH as f32;
    let current_box_height = (100f32 / 700f32) * IMAGE_WIDTH as f32;
    let current_hour_name_font_size = (40f32 / 700f32) * IMAGE_WIDTH as f32;
    let current_time_font_size = (30f32 / 700f32) * IMAGE_WIDTH as f32;

    let current_hour_rect = Rectangle::new()
        .set("x1", 0)
        .set("y1", 0)
        .set("width", current_box_width)
        .set("height", current_box_height);

    let current_hour_name = Text::new()
        .set("id", "current-hour-name")
        .set("font-size", current_hour_name_font_size)
        .set("text-anchor", "middle")
        .set("dominant-baseline", "mathematical")
        .set("x", current_box_width / 2.0)
        .set(
            "y",
            (current_box_height / 5.0) + (current_hour_name_font_size / 2.0),
        )
        .add(TextNode::new(HOUR_NAMES[utc_hour as usize]));

    let current_time_text = Text::new()
        .set("font-size", current_time_font_size)
        .set("text-anchor", "middle")
        .set("dominant-baseline", "mathematical")
        .set("x", current_box_width / 2.0)
        .set("y", current_box_height - (current_time_font_size / 2.0))
        .add(TextNode::new(format!(
            "{:02}:{:02}:{:02}",
            local_hour, local_minute, local_second
        )));

    let top_pos = if (6..=18).contains(&local_hour) {
        moon_radius * 1.5 // under the moon
    } else {
        0.0 - moon_radius * 1.5 - current_box_height // above the moon
    };

    let current_hour_group = Group::new()
        .set("id", "current-hour")
        .set(
            "transform",
            format!(
                "translate({}, {})",
                IMAGE_WIDTH as f32 / 2.0 - current_box_width / 2.0,
                IMAGE_WIDTH as f32 / 2.0 + top_pos
            ),
        )
        .add(current_hour_rect)
        .add(current_hour_name)
        .add(current_time_text);

    let mut document = 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);

    if let Some(..) = day_parts_group {
        document = document.add(day_parts_group.unwrap());
    }

    document
        .add(seasonal_clock)
        .add(moon_group)
        .add(dial)
        .add(current_hour_group)
}

fn main() {
    let xdg_dirs = xdg::BaseDirectories::new().unwrap();
    let config_path = xdg_dirs
        .place_config_file("seasonal-clock.toml")
        .expect("cannot create configuration directory");
    let data: std::io::Result<String> = fs::read_to_string(config_path);
    let config: Option<Config> = if let Ok(..) = data {
        let complete_config: CompleteConfig = toml::from_str(&data.unwrap()).unwrap();
        Some(complete_config.seasonal_clock)
    } else {
        None
    };

    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(())
}