// Copyright 2023 System76 <info@system76.com>
// SPDX-License-Identifier: GPL-3.0-only

use std::{collections::HashMap, process, time::Duration};

use cosmic::{
    app,
    applet::{menu_button, padded_control},
    cosmic_theme::Spacing,
    iced::{
        self,
        event::{
            listen_with,
            wayland::{self, LayerEvent},
            PlatformSpecific,
        },
        keyboard::{key::Named, Key},
        platform_specific::{
            runtime::wayland::layer_surface::SctkLayerSurfaceSettings,
            shell::commands::{
                layer_surface::{
                    destroy_layer_surface, get_layer_surface, Anchor, KeyboardInteractivity,
                },
                popup::{destroy_popup, get_popup},
            },
        },
        time,
        widget::{self, column, container, row},
        window, Alignment, Length, Subscription,
    },
    iced_runtime::core::layout::Limits,
    iced_widget::mouse_area,
    theme,
    widget::{
        autosize::autosize, button, divider, horizontal_space, icon, text, vertical_space, Column,
        Space,
    },
    Element, Task,
};

use logind_zbus::{
    manager::ManagerProxy,
    session::{SessionClass, SessionProxy, SessionType},
    user::UserProxy,
};
use once_cell::sync::Lazy;
use rustix::process::getuid;
use zbus::Connection;

pub mod cosmic_session;
mod localize;
pub mod session_manager;

use crate::{cosmic_session::CosmicSessionProxy, session_manager::SessionManagerProxy};

pub fn run() -> cosmic::iced::Result {
    localize::localize();

    cosmic::applet::run::<Power>(())
}

const COUNTDOWN_LENGTH: u8 = 60;
static CONFIRM_ID: Lazy<iced::id::Id> = Lazy::new(|| iced::id::Id::new("confirm-id"));
static AUTOSIZE_DIALOG_ID: Lazy<iced::id::Id> = Lazy::new(|| iced::id::Id::new("autosize-id"));

#[derive(Default)]
struct Power {
    core: cosmic::app::Core,
    icon_name: String,
    popup: Option<window::Id>,
    action_to_confirm: Option<(window::Id, PowerAction, u8)>,
}

#[derive(Debug, Clone, Copy)]
enum PowerAction {
    Lock,
    LogOut,
    Suspend,
    Restart,
    Shutdown,
}

impl PowerAction {
    fn perform(self) -> iced::Task<cosmic::app::Message<Message>> {
        let msg = |m| cosmic::app::message::app(Message::Zbus(m));
        match self {
            PowerAction::Lock => iced::Task::perform(lock(), msg),
            PowerAction::LogOut => iced::Task::perform(log_out(), msg),
            PowerAction::Suspend => iced::Task::perform(suspend(), msg),
            PowerAction::Restart => iced::Task::perform(restart(), msg),
            PowerAction::Shutdown => iced::Task::perform(shutdown(), msg),
        }
    }
}

#[derive(Debug, Clone)]
enum Message {
    Countdown,
    Action(PowerAction),
    TogglePopup,
    Settings,
    Confirm,
    Cancel,
    Zbus(Result<(), zbus::Error>),
    Closed(window::Id),
    LayerFocus,
}

impl cosmic::Application for Power {
    type Executor = cosmic::SingleThreadExecutor;
    type Flags = ();
    type Message = Message;
    const APP_ID: &'static str = "com.system76.CosmicAppletPower";

    fn core(&self) -> &cosmic::app::Core {
        &self.core
    }

    fn core_mut(&mut self) -> &mut cosmic::app::Core {
        &mut self.core
    }

    fn init(core: cosmic::app::Core, _flags: ()) -> (Self, app::Task<Message>) {
        (
            Self {
                core,
                icon_name: "system-shutdown-symbolic".to_string(),
                ..Default::default()
            },
            Task::none(),
        )
    }

    fn on_close_requested(&self, id: window::Id) -> Option<Message> {
        Some(Message::Closed(id))
    }

    fn subscription(&self) -> Subscription<Message> {
        let mut subscriptions = Vec::with_capacity(2);
        subscriptions.push(listen_with(|e, _status, _| match e {
            cosmic::iced::Event::PlatformSpecific(PlatformSpecific::Wayland(
                wayland::Event::Layer(LayerEvent::Focused, ..),
            )) => Some(Message::LayerFocus),
            cosmic::iced::Event::PlatformSpecific(PlatformSpecific::Wayland(
                wayland::Event::Layer(LayerEvent::Unfocused, ..),
            )) => Some(Message::Cancel),
            cosmic::iced::Event::Keyboard(iced::keyboard::Event::KeyPressed {
                key,
                text: _,
                modifiers,
                ..
            }) => match key {
                Key::Named(Named::Escape) => Some(Message::Cancel),
                _ => None,
            },
            _ => None,
        }));
        if self.action_to_confirm.is_some() {
            subscriptions
                .push(time::every(Duration::from_millis(1000)).map(|_| Message::Countdown));
        }
        Subscription::batch(subscriptions)
    }

    fn update(&mut self, message: Message) -> app::Task<Message> {
        match message {
            Message::TogglePopup => {
                if let Some(p) = self.popup.take() {
                    destroy_popup(p)
                } else {
                    let new_id = window::Id::unique();
                    self.popup.replace(new_id);

                    let mut popup_settings = self.core.applet.get_popup_settings(
                        self.core.main_window_id().unwrap(),
                        new_id,
                        Some((500, 500)),
                        None,
                        None,
                    );
                    popup_settings.positioner.size_limits = Limits::NONE
                        .min_width(100.0)
                        .min_height(100.0)
                        .max_height(400.0)
                        .max_width(500.0);
                    get_popup(popup_settings)
                }
            }
            Message::Settings => {
                let _ = process::Command::new("cosmic-settings").spawn();
                Task::none()
            }
            Message::Action(action) => {
                // Ask for user confirmation of non-destructive actions only
                if matches!(action, PowerAction::Lock | PowerAction::Suspend)
                    || matches!(action, PowerAction::Restart)
                        && matches!(self.action_to_confirm, Some((_, PowerAction::Shutdown, _)))
                {
                    action.perform()
                } else {
                    let id = window::Id::unique();
                    self.action_to_confirm = Some((id, action, COUNTDOWN_LENGTH));
                    get_layer_surface(SctkLayerSurfaceSettings {
                        id,
                        keyboard_interactivity: KeyboardInteractivity::Exclusive,
                        anchor: Anchor::empty(),
                        namespace: "dialog".into(),
                        size: None,
                        size_limits: Limits::NONE.min_width(1.0).min_height(1.0),
                        ..Default::default()
                    })
                }
            }
            Message::Zbus(result) => {
                if let Err(e) = result {
                    eprintln!("cosmic-applet-power ERROR: '{}'", e);
                }
                Task::none()
            }
            Message::Confirm => {
                if let Some((id, a, _)) = self.action_to_confirm.take() {
                    app::Task::batch(vec![destroy_layer_surface(id), a.perform()])
                } else {
                    Task::none()
                }
            }
            Message::Cancel => {
                if let Some((id, _, _)) = self.action_to_confirm.take() {
                    return destroy_layer_surface(id);
                }
                Task::none()
            }
            Message::Countdown => {
                if let Some((surface_id, a, countdown)) = self.action_to_confirm.as_mut() {
                    *countdown -= 1;
                    if *countdown == 0 {
                        let id = *surface_id;
                        let a = *a;

                        self.action_to_confirm = None;
                        return app::Task::batch(vec![destroy_layer_surface(id), a.perform()]);
                    }
                }
                Task::none()
            }
            Message::Closed(id) => {
                if self.popup == Some(id) {
                    self.popup = None;
                }
                Task::none()
            }
            Message::LayerFocus => button::focus(CONFIRM_ID.clone()),
        }
    }

    fn view(&self) -> Element<Message> {
        self.core
            .applet
            .icon_button(&self.icon_name)
            .on_press_down(Message::TogglePopup)
            .into()
    }

    fn view_window(&self, id: window::Id) -> Element<Message> {
        let Spacing {
            space_xxs,
            space_s,
            space_m,
            ..
        } = theme::active().cosmic().spacing;

        if matches!(self.popup, Some(p) if p == id) {
            let settings = menu_button(text::body(fl!("settings"))).on_press(Message::Settings);

            let session = column![
                menu_button(
                    row![
                        text_icon("system-lock-screen-symbolic", 24),
                        text::body(fl!("lock-screen")),
                        Space::with_width(Length::Fill),
                        text::body(fl!("lock-screen-shortcut")),
                    ]
                    .align_y(Alignment::Center)
                    .spacing(space_xxs)
                )
                .on_press(Message::Action(PowerAction::Lock)),
                menu_button(
                    row![
                        text_icon("system-log-out-symbolic", 24),
                        text::body(fl!("log-out")),
                        Space::with_width(Length::Fill),
                        text::body(fl!("log-out-shortcut")),
                    ]
                    .align_y(Alignment::Center)
                    .spacing(space_xxs)
                )
                .on_press(Message::Action(PowerAction::LogOut)),
            ];

            let power = row![
                power_buttons("system-suspend-symbolic", fl!("suspend"))
                    .on_press(Message::Action(PowerAction::Suspend)),
                power_buttons("system-reboot-symbolic", fl!("restart"))
                    .on_press(Message::Action(PowerAction::Restart)),
                power_buttons("system-shutdown-symbolic", fl!("shutdown"))
                    .on_press(Message::Action(PowerAction::Shutdown)),
            ]
            .spacing(space_m)
            .padding([0, space_m]);

            let content = column![
                settings,
                padded_control(divider::horizontal::default()).padding([space_xxs, space_s]),
                session,
                padded_control(divider::horizontal::default()).padding([space_xxs, space_s]),
                power
            ]
            .align_x(Alignment::Start)
            .padding([8, 0]);

            self.core
                .applet
                .popup_container(content)
                .max_height(400.)
                .max_width(500.)
                .into()
        } else if matches!(self.action_to_confirm, Some((c_id, _, _)) if c_id == id) {
            let cosmic_theme = self.core.system_theme().cosmic();
            let (_, power_action, countdown) = self.action_to_confirm.as_ref().unwrap();
            let action = match power_action {
                PowerAction::Lock => "lock-screen",
                PowerAction::LogOut => "log-out",
                PowerAction::Suspend => "suspend",
                PowerAction::Restart => "restart",
                PowerAction::Shutdown => "shutdown",
            };

            let title = fl!(
                "confirm-title",
                HashMap::from_iter(vec![("action", action)])
            );
            let countdown = &countdown.to_string();
            let mut dialog = cosmic::widget::dialog()
                .title(title)
                .body(fl!(
                    "confirm-body",
                    HashMap::from_iter(vec![("action", action), ("countdown", countdown)])
                ))
                .primary_action(
                    button::custom(min_width_and_height(
                        text::body(fl!("confirm", HashMap::from_iter(vec![("action", action)])))
                            .into(),
                        142.0,
                        32.0,
                    ))
                    .padding([0, cosmic_theme.space_s()])
                    .id(CONFIRM_ID.clone())
                    .class(theme::Button::Suggested)
                    .on_press(Message::Confirm),
                )
                .secondary_action(
                    button::custom(min_width_and_height(
                        text::body(fl!("cancel")).into(),
                        142.0,
                        32.0,
                    ))
                    .padding([0, cosmic_theme.space_s()])
                    .class(theme::Button::Standard)
                    .on_press(Message::Cancel),
                )
                .icon(text_icon(
                    match power_action {
                        PowerAction::Lock => "system-lock-screen-symbolic",
                        PowerAction::LogOut => "system-log-out-symbolic",
                        PowerAction::Suspend => "system-suspend-symbolic",
                        PowerAction::Restart => "system-restart-symbolic",
                        PowerAction::Shutdown => "system-shutdown-symbolic",
                    },
                    60,
                ));

            if matches!(power_action, PowerAction::Shutdown) {
                dialog = dialog.tertiary_action(
                    button::text(fl!("restart")).on_press(Message::Action(PowerAction::Restart)),
                );
            }
            Element::from(
                autosize(Element::from(container(dialog)), AUTOSIZE_DIALOG_ID.clone()).limits(
                    Limits::NONE
                        .min_width(1.)
                        .min_height(1.)
                        .max_width(900.)
                        .max_height(900.),
                ),
            )
        } else {
            //panic!("no view for window {}", id.0)
            widget::text("").into()
        }
        .into()
    }

    fn style(&self) -> Option<cosmic::iced_runtime::Appearance> {
        Some(cosmic::applet::style())
    }
}

fn power_buttons(name: &str, msg: String) -> cosmic::widget::Button<Message> {
    button::custom(
        column![text_icon(name, 40), text::body(msg)]
            .spacing(4)
            .align_x(Alignment::Center)
            .width(Length::Fill),
    )
    .width(Length::Fill)
    .height(Length::Fixed(76.0))
    .class(theme::Button::Text)
}

fn text_icon(name: &str, size: u16) -> cosmic::widget::Icon {
    icon::from_name(name).size(size).symbolic(true).icon()
}

// ### System helpers

async fn restart() -> zbus::Result<()> {
    let connection = Connection::system().await?;
    let manager_proxy = ManagerProxy::new(&connection).await?;
    manager_proxy.reboot(true).await
}

async fn shutdown() -> zbus::Result<()> {
    let connection = Connection::system().await?;
    let manager_proxy = ManagerProxy::new(&connection).await?;
    manager_proxy.power_off(true).await
}

async fn suspend() -> zbus::Result<()> {
    let connection = Connection::system().await?;
    let manager_proxy = ManagerProxy::new(&connection).await?;
    manager_proxy.suspend(true).await
}

async fn lock() -> zbus::Result<()> {
    let connection = Connection::system().await?;
    let manager_proxy = ManagerProxy::new(&connection).await?;
    // Get the session this current process is running in
    let our_uid = getuid().as_raw() as u32;
    let user_path = manager_proxy.get_user(our_uid).await?;
    let user = UserProxy::builder(&connection)
        .path(user_path)?
        .build()
        .await?;
    // Lock all non-TTY sessions of this user
    let sessions = user.sessions().await?;
    let mut locked_successfully = false;
    for (_, session_path) in sessions {
        let Ok(session) = SessionProxy::builder(&connection)
            .path(session_path)?
            .build()
            .await
        else {
            continue;
        };

        if session.class().await == Ok(SessionClass::User)
            && session.type_().await? != SessionType::TTY
            && session.lock().await.is_ok()
        {
            locked_successfully = true;
        }
    }

    if locked_successfully {
        Ok(())
    } else {
        Err(zbus::Error::Failure("locking session failed".to_string()))
    }
}

async fn log_out() -> zbus::Result<()> {
    let session_type = std::env::var("XDG_CURRENT_DESKTOP").ok();
    let connection = Connection::session().await?;
    match session_type.as_ref().map(|s| s.trim()) {
        Some("pop:GNOME") => {
            let manager_proxy = SessionManagerProxy::new(&connection).await?;
            manager_proxy.logout(0).await?;
        }
        // By default assume COSMIC
        _ => {
            let cosmic_session = CosmicSessionProxy::new(&connection).await?;
            cosmic_session.exit().await?;
        }
    }
    Ok(())
}

fn min_width_and_height<'a>(
    e: Element<'a, Message>,
    width: impl Into<Length>,
    height: impl Into<Length>,
) -> Column<'a, Message> {
    column![
        row![e, vertical_space().height(height)].align_y(Alignment::Center),
        horizontal_space().width(width)
    ]
    .align_x(Alignment::Center)
}