// ABOUTME: Entry point for Moonlock — secure Wayland lockscreen.
// ABOUTME: Sets up GTK Application, ext-session-lock-v1, Panic-Hook, and multi-monitor windows.

mod auth;
mod config;
mod fingerprint;
mod i18n;
mod lockscreen;
mod power;
mod users;

use gdk4 as gdk;
use gtk4::prelude::*;
use gtk4::{self as gtk, gio};
use gtk4_session_lock;
use std::cell::{Cell, RefCell};
use std::rc::Rc;

use crate::fingerprint::FingerprintListener;

fn load_css(display: &gdk::Display) {
    let css_provider = gtk::CssProvider::new();
    css_provider.load_from_resource("/dev/moonarch/moonlock/style.css");
    gtk::style_context_add_provider_for_display(
        display,
        &css_provider,
        gtk::STYLE_PROVIDER_PRIORITY_USER,
    );
}

fn activate(app: &gtk::Application) {
    let display = match gdk::Display::default() {
        Some(d) => d,
        None => {
            log::error!("No display available — cannot start lockscreen UI");
            return;
        }
    };

    load_css(&display);

    let config = config::load_config(None);

    if gtk4_session_lock::is_supported() {
        activate_with_session_lock(app, &display, &config);
    } else {
        #[cfg(debug_assertions)]
        {
            log::warn!("ext-session-lock-v1 not supported — running in development mode");
            activate_without_lock(app, &config);
        }
        #[cfg(not(debug_assertions))]
        {
            log::error!("ext-session-lock-v1 not supported — refusing to run without session lock");
            std::process::exit(1);
        }
    }
}

fn activate_with_session_lock(
    app: &gtk::Application,
    display: &gdk::Display,
    config: &config::Config,
) {
    let lock = gtk4_session_lock::Instance::new();

    // Load wallpaper before lock — connect_monitor fires during lock() and needs the
    // texture. This means disk I/O happens before locking, but loading a local JPEG
    // is fast enough that the delay is negligible.
    let bg_texture: Rc<Option<gdk::Texture>> = Rc::new(
        config::resolve_background_path(config)
            .and_then(|path| lockscreen::load_background_texture(&path)),
    );

    // Shared unlock callback — unlocks session and quits.
    // Guard prevents double-unlock if PAM and fingerprint succeed simultaneously.
    let lock_clone = lock.clone();
    let app_clone = app.clone();
    let already_unlocked = Rc::new(Cell::new(false));
    let au = already_unlocked.clone();
    let unlock_callback: Rc<dyn Fn()> = Rc::new(move || {
        if au.get() {
            log::debug!("Unlock already triggered, ignoring duplicate");
            return;
        }
        au.set(true);
        lock_clone.unlock();
        app_clone.quit();
    });

    // Shared caches for multi-monitor — first monitor renders, rest reuse
    let blur_cache: Rc<RefCell<Option<gdk::Texture>>> = Rc::new(RefCell::new(None));
    let avatar_cache: Rc<RefCell<Option<gdk::Texture>>> = Rc::new(RefCell::new(None));

    // Shared config for use in the monitor signal handler
    let config = Rc::new(config.clone());

    // Shared handles list — populated by connect_monitor, read by fingerprint init
    let all_handles: Rc<RefCell<Vec<lockscreen::LockscreenHandles>>> =
        Rc::new(RefCell::new(Vec::new()));

    // Shared fingerprint listener — None until async init completes.
    // The monitor handler checks this to wire up FP labels on hotplugged monitors.
    let shared_fp: Rc<RefCell<Option<Rc<RefCell<FingerprintListener>>>>> =
        Rc::new(RefCell::new(None));

    // The ::monitor signal fires once per existing monitor at lock(), and again
    // whenever a monitor is hotplugged (e.g. after suspend/resume). This replaces
    // the old manual monitor iteration and handles hotplug automatically.
    let lock_for_signal = lock.clone();
    lock.connect_monitor(glib::clone!(
        #[strong]
        app,
        #[strong]
        config,
        #[strong]
        bg_texture,
        #[strong]
        unlock_callback,
        #[strong]
        blur_cache,
        #[strong]
        avatar_cache,
        #[strong]
        all_handles,
        #[strong]
        shared_fp,
        move |_instance, monitor| {
            log::debug!("Monitor signal: creating lockscreen window");
            let mut handles = lockscreen::create_lockscreen_window(
                bg_texture.as_ref().as_ref(),
                &config,
                &app,
                unlock_callback.clone(),
                &blur_cache,
                &avatar_cache,
            );
            lock_for_signal.assign_window_to_monitor(&handles.window, monitor);
            handles.window.present();
            handles.monitor = Some(monitor.clone());

            // If fingerprint is already initialized, wire up the label
            if let Some(ref fp_rc) = *shared_fp.borrow() {
                lockscreen::show_fingerprint_label(&handles, fp_rc);
            }

            all_handles.borrow_mut().push(handles);
        }
    ));

    // connect_monitor only ADDS — it never tells us when a monitor powers off on
    // suspend. gtk4-session-lock then unmaps and drops its own ref to that monitor's
    // window, but the GtkApplication and all_handles still hold refs, so the orphaned
    // window survives until unlock — where gtk_window_destroy dereferences its now-NULL
    // monitor association and segfaults. Watch the display's monitor list and prune any
    // window whose monitor is no longer valid, releasing our refs (the lib doc points to
    // "GTK APIs" for exactly this). We release refs, not destroy — the lib already
    // unmapped+dereffed the window.
    display.monitors().connect_items_changed(glib::clone!(
        #[weak]
        app,
        #[strong]
        all_handles,
        move |_, _, _, _| {
            all_handles.borrow_mut().retain(|h| {
                let alive = h.monitor.as_ref().is_none_or(gdk::Monitor::is_valid);
                if !alive {
                    log::info!("Monitor removed — pruning its lockscreen window");
                    app.remove_window(&h.window);
                }
                alive
            });
        }
    ));

    lock.lock();

    // Async fprintd initialization — runs after windows are visible
    if config.fingerprint_enabled {
        init_fingerprint_async(all_handles, shared_fp);
    }
}

/// Initialize fprintd asynchronously after windows are visible.
/// Uses a single FingerprintListener shared across all monitors —
/// only the first monitor's handles get the fingerprint verification wired up.
/// The `shared_fp` is set after init so that the connect_monitor handler can
/// wire up FP labels on monitors that appear after initialization.
fn init_fingerprint_async(
    all_handles: Rc<RefCell<Vec<lockscreen::LockscreenHandles>>>,
    shared_fp: Rc<RefCell<Option<Rc<RefCell<FingerprintListener>>>>>,
) {
    glib::spawn_future_local(async move {
        let mut listener = FingerprintListener::new();
        listener.init_async().await;

        // Extract username without holding a borrow across the await below —
        // otherwise a concurrent connect_monitor signal (hotplug / suspend-resume)
        // that tries to borrow_mut() panics at runtime.
        let username = {
            let handles = all_handles.borrow();
            if handles.is_empty() {
                return;
            }
            let u = handles[0].username.clone();
            if u.is_empty() {
                return;
            }
            u
        };

        if !listener.is_available_async(&username).await {
            log::debug!("fprintd not available or no enrolled fingers");
            return;
        }

        let fp_rc = Rc::new(RefCell::new(listener));

        // Re-borrow after the await — no further awaits in this scope, so it is
        // safe to hold the borrow briefly while wiring up the labels.
        {
            let handles = all_handles.borrow();
            for h in handles.iter() {
                lockscreen::show_fingerprint_label(h, &fp_rc);
            }
            lockscreen::start_fingerprint(&handles[0], &fp_rc);
        }

        // Publish the listener so hotplugged monitors get FP labels too
        *shared_fp.borrow_mut() = Some(fp_rc);
    });
}

#[cfg(debug_assertions)]
fn activate_without_lock(
    app: &gtk::Application,
    config: &config::Config,
) {
    let bg_texture = config::resolve_background_path(config)
        .and_then(|path| lockscreen::load_background_texture(&path));

    let app_clone = app.clone();
    let unlock_callback: Rc<dyn Fn()> = Rc::new(move || {
        app_clone.quit();
    });

    let blur_cache = Rc::new(RefCell::new(None));
    let avatar_cache = Rc::new(RefCell::new(None));
    let handles = lockscreen::create_lockscreen_window(
        bg_texture.as_ref(),
        config,
        app,
        unlock_callback,
        &blur_cache,
        &avatar_cache,
    );
    handles.window.set_default_size(800, 600);
    handles.window.present();

    // Async fprintd initialization for development mode
    if config.fingerprint_enabled {
        let all_handles = Rc::new(RefCell::new(vec![handles]));
        let shared_fp = Rc::new(RefCell::new(None));
        init_fingerprint_async(all_handles, shared_fp);
    }
}

fn setup_logging() {
    match systemd_journal_logger::JournalLog::new() {
        Ok(logger) => {
            if let Err(e) = logger.install() {
                eprintln!("Failed to install journal logger: {e}");
            }
        }
        Err(e) => {
            eprintln!("Failed to create journal logger: {e}");
        }
    }
    // Debug level is only selectable in debug builds. Release binaries ignore
    // MOONLOCK_DEBUG so a session script cannot escalate log verbosity to leak
    // fprintd / D-Bus internals into the journal.
    #[cfg(debug_assertions)]
    let level = if std::env::var("MOONLOCK_DEBUG").is_ok() {
        log::LevelFilter::Debug
    } else {
        log::LevelFilter::Info
    };
    #[cfg(not(debug_assertions))]
    let level = log::LevelFilter::Info;
    log::set_max_level(level);
}

fn install_panic_hook() {
    // Install a panic hook BEFORE starting the app.
    // On panic, we log but NEVER unlock. The compositor's ext-session-lock-v1
    // policy keeps the screen locked when the client crashes.
    let default_hook = std::panic::take_hook();
    std::panic::set_hook(Box::new(move |info| {
        log::error!("PANIC — screen stays locked (compositor policy): {info}");
        default_hook(info);
    }));
}

fn main() {
    install_panic_hook();
    setup_logging();

    // Root check — moonlock should not run as root
    if nix::unistd::getuid().is_root() {
        log::error!("Moonlock should not run as root");
        std::process::exit(1);
    }
    log::info!("Moonlock starting");

    // Register compiled GResources
    gio::resources_register_include!("moonlock.gresource").expect("Failed to register resources");

    let app = gtk::Application::builder()
        .application_id("dev.moonarch.moonlock")
        .build();

    app.connect_activate(activate);
    app.run();
}