#![allow(clippy::single_match)]

use calloop::{channel, EventLoop};
use calloop_wayland_source::WaylandSource;
use cosmic_config::{calloop::ConfigWatchSource, CosmicConfigEntry};
use cosmic_idle_config::CosmicIdleConfig;
use futures_lite::stream::StreamExt;
use std::{
    process::Command,
    sync::{Arc, Mutex},
};
use upower_dbus::UPowerProxy;
use wayland_client::{
    delegate_noop,
    globals::{registry_queue_init, GlobalListContents},
    protocol::{wl_compositor, wl_output, wl_pointer, wl_registry, wl_seat},
    Connection, Dispatch, Proxy, QueueHandle,
};
use wayland_protocols::{
    ext::idle_notify::v1::client::{ext_idle_notification_v1, ext_idle_notifier_v1},
    wp::{
        single_pixel_buffer::v1::client::wp_single_pixel_buffer_manager_v1,
        viewporter::client::{wp_viewport, wp_viewporter},
    },
};
use wayland_protocols_wlr::{
    layer_shell::v1::client::zwlr_layer_shell_v1,
    output_power_management::v1::client::{zwlr_output_power_manager_v1, zwlr_output_power_v1},
};

mod fade_black;
use fade_black::FadeBlackSurface;
mod freedesktop_screensaver;

#[derive(Debug)]
enum Event {
    OnBattery(bool),
}

struct IdleNotification {
    notification: ext_idle_notification_v1::ExtIdleNotificationV1,
    time: u32,
}

impl IdleNotification {
    fn new(inner: &StateInner, time: u32) -> Self {
        let notification =
            inner
                .idle_notifier
                .get_idle_notification(time, &inner.seat, &inner.qh, ());
        Self { notification, time }
    }
}

impl Drop for IdleNotification {
    fn drop(&mut self) {
        self.notification.destroy();
    }
}

async fn receive_battery_task(sender: channel::Sender<Event>) -> zbus::Result<()> {
    let connection = zbus::Connection::system().await?;
    let upower = UPowerProxy::new(&connection).await?;
    let mut stream = upower.receive_on_battery_changed().await;
    while let Some(event) = stream.next().await {
        let _ = sender.send(Event::OnBattery(event.get().await?));
    }
    Ok(())
}

#[derive(Debug)]
struct Output {
    output: wl_output::WlOutput,
    output_power: zwlr_output_power_v1::ZwlrOutputPowerV1,
    fade_surface: Option<FadeBlackSurface>,
    global_name: u32,
}

// Immutate references to globals, needed for calls
struct StateInner {
    output_power_manager: zwlr_output_power_manager_v1::ZwlrOutputPowerManagerV1,
    compositor: wl_compositor::WlCompositor,
    layer_shell: zwlr_layer_shell_v1::ZwlrLayerShellV1,
    viewporter: wp_viewporter::WpViewporter,
    single_pixel_buffer_manager: wp_single_pixel_buffer_manager_v1::WpSinglePixelBufferManagerV1,
    idle_notifier: ext_idle_notifier_v1::ExtIdleNotifierV1,
    seat: wl_seat::WlSeat,
    qh: QueueHandle<State>,
}

struct State {
    inner: StateInner,
    outputs: Vec<Output>,
    conf: CosmicIdleConfig,
    screen_off_idle_notification: Option<IdleNotification>,
    suspend_idle_notification: Option<IdleNotification>,
    on_battery: bool,
    screensaver_inhibitors: Arc<Mutex<Vec<freedesktop_screensaver::Inhibitor>>>,
}

impl State {
    fn update_screen_off_idle(&mut self, is_idle: bool) {
        if !self.screensaver_inhibitors.lock().unwrap().is_empty() {
            return;
        }
        for output in &mut self.outputs {
            if is_idle {
                output.fade_surface = Some(FadeBlackSurface::new(&self.inner, &output.output));
            } else {
                output.fade_surface = None;
                output.output_power.set_mode(zwlr_output_power_v1::Mode::On);
            }
        }
    }

    fn update_suspend_idle(&mut self, is_idle: bool) {
        if !self.screensaver_inhibitors.lock().unwrap().is_empty() {
            return;
        }
        if is_idle {
            // TODO: Make command configurable
            match Command::new("systemctl").arg("suspend").status() {
                Ok(status) if status.success() => {}
                Ok(status) => {
                    log::error!("suspend command failed with exit status {}", status)
                }
                Err(err) => log::error!("failed to run suspend command: {}", err),
            }
        }
    }

    fn recreate_notification(&mut self) {
        if self.screen_off_idle_notification.as_ref().map(|x| x.time) != self.conf.screen_off_time {
            self.screen_off_idle_notification = self
                .conf
                .screen_off_time
                .map(|time| IdleNotification::new(&self.inner, time));
            self.update_screen_off_idle(false);
        }
        let suspend_time = if self.on_battery {
            self.conf.suspend_on_battery_time
        } else {
            self.conf.suspend_on_ac_time
        };
        if self.suspend_idle_notification.as_ref().map(|x| x.time) != suspend_time {
            self.suspend_idle_notification =
                suspend_time.map(|time| IdleNotification::new(&self.inner, time));
            self.update_suspend_idle(false);
        }
    }

    fn handle_event(&mut self, event: Event) {
        match event {
            Event::OnBattery(value) => {
                self.on_battery = value;
            }
        }
    }
}

fn main() {
    env_logger::init();

    let connection = Connection::connect_to_env().unwrap();
    let (globals, event_queue) = registry_queue_init::<State>(&connection).unwrap();
    let qh = event_queue.handle();

    let output_power_manager = globals
        .bind::<zwlr_output_power_manager_v1::ZwlrOutputPowerManagerV1, _, _>(&qh, 1..=1, ())
        .unwrap();

    let idle_notifier = globals
        .bind::<ext_idle_notifier_v1::ExtIdleNotifierV1, _, _>(&qh, 1..=1, ())
        .unwrap();

    let seat = globals
        .bind::<wl_seat::WlSeat, _, _>(&qh, 1..=1, ())
        .unwrap();
    seat.get_pointer(&qh, ());

    let compositor = globals
        .bind::<wl_compositor::WlCompositor, _, _>(&qh, 1..=1, ())
        .unwrap();

    let layer_shell = globals
        .bind::<zwlr_layer_shell_v1::ZwlrLayerShellV1, _, _>(&qh, 1..=4, ())
        .unwrap();

    let viewporter = globals
        .bind::<wp_viewporter::WpViewporter, _, _>(&qh, 1..=1, ())
        .unwrap();

    let single_pixel_buffer_manager = globals
        .bind::<wp_single_pixel_buffer_manager_v1::WpSinglePixelBufferManagerV1, _, _>(
            &qh,
            1..=1,
            (),
        )
        .unwrap();

    let outputs = globals.contents().with_list(|list| {
        list.iter()
            .filter(|global| global.interface == wl_output::WlOutput::interface().name)
            .map(|global| {
                let output = globals
                    .registry()
                    .bind(global.name, global.version.min(3), &qh, ());
                let output_power = output_power_manager.get_output_power(&output, &qh, ());
                Output {
                    output,
                    output_power,
                    fade_surface: None,
                    global_name: global.name,
                }
            })
            .collect()
    });

    let config = cosmic_config::Config::new("com.system76.CosmicIdle", 1).unwrap();
    let conf = CosmicIdleConfig::get_entry(&config).unwrap_or_else(|(errs, conf)| {
        for err in errs {
            log::error!("Loading config: {}", err);
        }
        conf
    });

    let screensaver_inhibitors = Arc::new(Mutex::new(Vec::new()));

    let mut state = State {
        inner: StateInner {
            compositor,
            output_power_manager,
            layer_shell,
            viewporter,
            single_pixel_buffer_manager,
            idle_notifier,
            seat,
            qh,
        },
        screen_off_idle_notification: None,
        suspend_idle_notification: None,
        outputs,
        conf,
        on_battery: false,
        screensaver_inhibitors: screensaver_inhibitors.clone(),
    };
    state.recreate_notification();

    let mut event_loop: EventLoop<State> = EventLoop::try_new().unwrap();

    WaylandSource::new(connection, event_queue)
        .insert(event_loop.handle())
        .unwrap();

    if let Ok(source) = ConfigWatchSource::new(&config) {
        event_loop
            .handle()
            .insert_source(source, |(config, keys), _, state| {
                state.conf.update_keys(&config, &keys);
                state.recreate_notification();
            })
            .unwrap();
    }

    let (executor, scheduler) = calloop::futures::executor().unwrap();
    let (sender, receiver) = channel::channel();
    scheduler
        .schedule(async move {
            if let Err(err) = receive_battery_task(sender).await {
                log::error!("Getting battery status from upower: {}", err);
            }
        })
        .unwrap();
    scheduler
        .schedule(async move {
            if let Ok(connection) = zbus::Connection::session().await {
                if let Err(err) =
                    freedesktop_screensaver::serve(&connection, screensaver_inhibitors).await
                {
                    log::error!("failed to serve FreeDesktop screensaver interface: {}", err);
                }
            }
        })
        .unwrap();
    event_loop
        .handle()
        .insert_source(executor, |_, _, _| {})
        .unwrap();
    event_loop
        .handle()
        .insert_source(receiver, |event, _, state| {
            if let channel::Event::Msg(event) = event {
                state.handle_event(event);
            }
        })
        .unwrap();

    while let Ok(_) = event_loop.dispatch(None, &mut state) {}
}

impl Dispatch<wl_registry::WlRegistry, GlobalListContents> for State {
    fn event(
        state: &mut Self,
        registry: &wl_registry::WlRegistry,
        event: wl_registry::Event,
        _: &GlobalListContents,
        _: &Connection,
        qh: &QueueHandle<Self>,
    ) {
        match event {
            wl_registry::Event::Global {
                name,
                interface,
                version,
            } => {
                if interface == "wl_output" {
                    let output = registry.bind(name, version.min(3), qh, ());
                    let output_power =
                        state
                            .inner
                            .output_power_manager
                            .get_output_power(&output, &qh, ());
                    state.outputs.push(Output {
                        output,
                        output_power,
                        fade_surface: None,
                        global_name: name,
                    });
                }
            }
            wl_registry::Event::GlobalRemove { name } => {
                state.outputs.retain(|output| output.global_name != name);
            }
            _ => {}
        }
    }
}

impl Dispatch<ext_idle_notification_v1::ExtIdleNotificationV1, ()> for State {
    fn event(
        state: &mut Self,
        notification: &ext_idle_notification_v1::ExtIdleNotificationV1,
        event: ext_idle_notification_v1::Event,
        _: &(),
        _: &Connection,
        _qh: &QueueHandle<Self>,
    ) {
        let is_idle = match event {
            ext_idle_notification_v1::Event::Idled => true,
            ext_idle_notification_v1::Event::Resumed => false,
            _ => unreachable!(),
        };
        if state
            .screen_off_idle_notification
            .as_ref()
            .map(|x| &x.notification)
            == Some(notification)
        {
            state.update_screen_off_idle(is_idle);
        } else if state
            .suspend_idle_notification
            .as_ref()
            .map(|x| &x.notification)
            == Some(notification)
        {
            state.update_suspend_idle(is_idle);
        }
    }
}

impl Dispatch<wl_pointer::WlPointer, ()> for State {
    fn event(
        _: &mut Self,
        pointer: &wl_pointer::WlPointer,
        event: wl_pointer::Event,
        _: &(),
        _: &Connection,
        _: &QueueHandle<Self>,
    ) {
        match event {
            wl_pointer::Event::Enter {
                serial,
                surface: _,
                surface_x: _,
                surface_y: _,
            } => {
                pointer.set_cursor(serial, None, 0, 0);
            }
            _ => {}
        }
    }
}

delegate_noop!(State: ignore wl_output::WlOutput);
delegate_noop!(State: zwlr_output_power_manager_v1::ZwlrOutputPowerManagerV1);
delegate_noop!(State: ignore zwlr_output_power_v1::ZwlrOutputPowerV1);
delegate_noop!(State: ext_idle_notifier_v1::ExtIdleNotifierV1);
delegate_noop!(State: ignore wl_seat::WlSeat); // XXX
delegate_noop!(State: zwlr_layer_shell_v1::ZwlrLayerShellV1);
delegate_noop!(State: wp_viewporter::WpViewporter);
delegate_noop!(State: wp_viewport::WpViewport);
delegate_noop!(State: wl_compositor::WlCompositor);