gtk: handle exit of service properly

src/frontend/gtk/window.rs

@@ -1,6 +1,6 @@
 mod imp;
 
-use std::io::Write;
+use std::{io::Write, process};
 
 use adw::prelude::*;
 use adw::subclass::prelude::*;
@@ -218,4 +218,16 @@ impl Window {
         let toast_overlay = &self.imp().toast_overlay;
         toast_overlay.add_toast(toast);
     }
+
+    pub fn show_exit_dialog(&self, msg: &str) {
+        let dialog = adw::MessageDialog::builder()
+            .transient_for(self)
+            // .heading(msg)
+            .body(msg)
+            .build();
+
+        dialog.add_response("close", "Close");
+        dialog.connect_response(Some("close"), move |_, _| process::exit(1));
+        dialog.show();
+    }
 }