step 8-10: notification daemon (zbus), popup window, SIGHUP theme reload

src/main.rs

@@ -99,6 +99,7 @@ impl SimpleComponent for App {
         bar::workspaces::spawn_watcher(sender.clone());
         bar::clock::spawn_ticker(sender.clone());
         bar::stats::spawn_poller(sender);
+        notifications::spawn();
 
         ComponentParts { model, widgets }
     }
@@ -138,6 +139,16 @@ impl App {
 }
 
 fn main() {
+    // Reload theme CSS on SIGHUP (e.g. after pywal runs).
+    relm4::spawn(async {
+        use tokio::signal::unix::{signal, SignalKind};
+        let mut stream = signal(SignalKind::hangup()).expect("SIGHUP handler");
+        loop {
+            stream.recv().await;
+            gtk4::glib::MainContext::default().invoke(theme::apply);
+        }
+    });
+
     let app = RelmApp::new("sh.breadway.aster");
     app.run::<App>(());
 }

src/notifications/mod.rs

@@ -1 +1,80 @@
 pub mod popup;
+
+use std::sync::atomic::{AtomicU32, Ordering};
+use tokio::sync::mpsc;
+use zbus::zvariant::OwnedValue;
+
+pub enum NotifEvent {
+    Show { id: u32, app_name: String, summary: String, body: String, timeout_ms: u32 },
+    Close(u32),
+}
+
+struct NotifServer {
+    tx: mpsc::Sender<NotifEvent>,
+    next_id: AtomicU32,
+}
+
+#[zbus::interface(name = "org.freedesktop.Notifications")]
+impl NotifServer {
+    async fn notify(
+        &self,
+        app_name: &str,
+        replaces_id: u32,
+        _app_icon: &str,
+        summary: &str,
+        body: &str,
+        _actions: Vec<String>,
+        _hints: std::collections::HashMap<String, OwnedValue>,
+        expire_timeout: i32,
+    ) -> u32 {
+        let id = if replaces_id != 0 {
+            replaces_id
+        } else {
+            self.next_id.fetch_add(1, Ordering::Relaxed)
+        };
+        let timeout_ms = if expire_timeout <= 0 { 5000 } else { expire_timeout as u32 };
+        let _ = self
+            .tx
+            .send(NotifEvent::Show {
+                id,
+                app_name: app_name.to_string(),
+                summary: summary.to_string(),
+                body: body.to_string(),
+                timeout_ms,
+            })
+            .await;
+        id
+    }
+
+    async fn close_notification(&self, id: u32) {
+        let _ = self.tx.send(NotifEvent::Close(id)).await;
+    }
+
+    fn get_capabilities(&self) -> Vec<String> {
+        vec!["body".to_string()]
+    }
+
+    fn get_server_information(&self) -> (String, String, String, String) {
+        ("aster".into(), "breadway".into(), "0.1.0".into(), "1.2".into())
+    }
+}
+
+pub fn spawn() {
+    let (tx, rx) = mpsc::channel(32);
+
+    relm4::spawn(async move {
+        let server = NotifServer { tx, next_id: AtomicU32::new(1) };
+        let _conn = zbus::connection::Builder::session()
+            .unwrap()
+            .name("org.freedesktop.Notifications")
+            .unwrap()
+            .serve_at("/org/freedesktop/Notifications", server)
+            .unwrap()
+            .build()
+            .await
+            .expect("failed to claim org.freedesktop.Notifications");
+        std::future::pending::<()>().await
+    });
+
+    relm4::spawn_local(popup::run(rx));
+}

src/notifications/popup.rs

@@ -1 +1,98 @@
+use std::{cell::RefCell, collections::HashMap, rc::Rc, time::Duration};
 
+use gtk4::prelude::*;
+use gtk4_layer_shell::{Edge, Layer, LayerShell};
+use tokio::sync::mpsc::Receiver;
+
+use super::NotifEvent;
+
+type Cards = Rc<RefCell<HashMap<u32, gtk4::Box>>>;
+
+pub async fn run(mut rx: Receiver<NotifEvent>) {
+    let window = create_window();
+    let cards_box = gtk4::Box::new(gtk4::Orientation::Vertical, 4);
+    cards_box.set_margin_top(8);
+    cards_box.set_margin_bottom(8);
+    cards_box.set_margin_start(8);
+    cards_box.set_margin_end(8);
+    window.set_child(Some(&cards_box));
+
+    let cards: Cards = Rc::new(RefCell::new(HashMap::new()));
+
+    while let Some(event) = rx.recv().await {
+        match event {
+            NotifEvent::Show { id, app_name, summary, body, timeout_ms } => {
+                // Replace existing card with same id (replaces_id case)
+                if let Some(old) = cards.borrow_mut().remove(&id) {
+                    cards_box.remove(&old);
+                }
+                let card = make_card(&app_name, &summary, &body);
+                cards_box.prepend(&card);
+                cards.borrow_mut().insert(id, card.clone());
+                window.set_visible(true);
+
+                // Auto-dismiss via GLib-native timer (safe inside spawn_local)
+                let cards_clone = cards.clone();
+                let cards_box_clone = cards_box.clone();
+                let win_clone = window.clone();
+                relm4::spawn_local(async move {
+                    gtk4::glib::timeout_future(Duration::from_millis(timeout_ms as u64)).await;
+                    dismiss(&cards_box_clone, &win_clone, &cards_clone, id);
+                });
+            }
+            NotifEvent::Close(id) => {
+                dismiss(&cards_box, &window, &cards, id);
+            }
+        }
+    }
+}
+
+fn dismiss(cards_box: &gtk4::Box, window: &gtk4::Window, cards: &Cards, id: u32) {
+    if let Some(card) = cards.borrow_mut().remove(&id) {
+        cards_box.remove(&card);
+    }
+    if cards.borrow().is_empty() {
+        window.set_visible(false);
+    }
+}
+
+fn create_window() -> gtk4::Window {
+    let window = gtk4::Window::new();
+    window.add_css_class("aster-notification");
+    window.init_layer_shell();
+    window.set_layer(Layer::Overlay);
+    window.set_anchor(Edge::Top, true);
+    window.set_anchor(Edge::Right, true);
+    window.set_margin(Edge::Top, 20);
+    window.set_margin(Edge::Right, 20);
+    window.set_default_width(320);
+    window
+}
+
+fn make_card(app_name: &str, summary: &str, body: &str) -> gtk4::Box {
+    let card = gtk4::Box::new(gtk4::Orientation::Vertical, 4);
+    card.add_css_class("notification-card");
+
+    if !app_name.is_empty() {
+        let lbl = gtk4::Label::new(Some(app_name));
+        lbl.add_css_class("notification-app");
+        lbl.set_xalign(0.0);
+        card.append(&lbl);
+    }
+
+    let summary_lbl = gtk4::Label::new(Some(summary));
+    summary_lbl.add_css_class("notification-summary");
+    summary_lbl.set_xalign(0.0);
+    summary_lbl.set_wrap(true);
+    card.append(&summary_lbl);
+
+    if !body.is_empty() {
+        let body_lbl = gtk4::Label::new(Some(body));
+        body_lbl.add_css_class("notification-body");
+        body_lbl.set_xalign(0.0);
+        body_lbl.set_wrap(true);
+        card.append(&body_lbl);
+    }
+
+    card
+}

src/theme.rs

@@ -48,7 +48,14 @@ fn load_css() -> String {
          .workspace-btn {{ background: {surface}; color: {fg}; border-radius: 4px;\
              border: none; min-width: 24px; padding: 0 8px; }}\
          .workspace-btn:hover, .workspace-btn.active {{ background: {accent}; }}\
-         label {{ color: {fg}; }}",
+         label {{ color: {fg}; }}\
+         window.aster-notification {{ background-color: alpha({bg_plain}, 0.95); }}\
+         .notification-card {{ background: {surface}; border-radius: 6px;\
+             padding: 10px; margin-bottom: 4px; }}\
+         .notification-summary {{ font-weight: bold; color: {fg}; }}\
+         .notification-app {{ color: {fg}; opacity: 0.6; }}\
+         .notification-body {{ color: {fg}; }}",
+        bg_plain = bg,
         bg_rgba = hex_to_rgba(&bg, 0.92),
         surface = surface,
         fg = fg,