fix: add fallbacks for old libadwaita widgets

cellar-gtk.py

@@ -184,6 +184,86 @@ class CompatBanner(Gtk.Revealer):
         self.set_reveal_child(revealed)
 
 
+class CompatToolbarView(Gtk.Box):
+    """Fallback for `Adw.ToolbarView` (available since libadwaita 1.4)."""
+
+    def __init__(self) -> None:
+        super().__init__(orientation=Gtk.Orientation.VERTICAL)
+        self._content: Gtk.Widget | None = None
+
+    def add_top_bar(self, widget: Gtk.Widget) -> None:
+        self.append(widget)
+
+    def set_content(self, widget: Gtk.Widget) -> None:
+        if self._content is not None:
+            self.remove(self._content)
+        self._content = widget
+        widget.set_vexpand(True)
+        self.append(widget)
+
+
+class CompatEntryRow(Adw.ActionRow):
+    """Fallback for `Adw.EntryRow` (available since libadwaita 1.2)."""
+
+    def __init__(self, title: str = ""):
+        super().__init__(title=title)
+        self._entry = Gtk.Entry()
+        self._entry.set_hexpand(True)
+        self.add_suffix(self._entry)
+        self.set_activatable_widget(self._entry)
+
+    def get_text(self) -> str:
+        return self._entry.get_text()
+
+    def set_text(self, text: str) -> None:
+        self._entry.set_text(text)
+
+
+class CompatSwitchRow(Adw.ActionRow):
+    """Fallback for `Adw.SwitchRow` (available since libadwaita 1.4)."""
+
+    def __init__(self, title: str = ""):
+        super().__init__(title=title)
+        self._switch = Gtk.Switch()
+        self._switch.set_valign(Gtk.Align.CENTER)
+        self.add_suffix(self._switch)
+        self.set_activatable_widget(self._switch)
+
+    def get_active(self) -> bool:
+        return self._switch.get_active()
+
+    def set_active(self, active: bool) -> None:
+        self._switch.set_active(active)
+
+    def connect_active_notify(self, callback: Callable[..., None]) -> None:
+        self._switch.connect("notify::active", callback)
+
+
+def make_toolbar_view() -> Gtk.Widget:
+    if hasattr(Adw, "ToolbarView"):
+        return Adw.ToolbarView()
+    return CompatToolbarView()
+
+
+def make_entry_row(title: str) -> Gtk.Widget:
+    if hasattr(Adw, "EntryRow"):
+        return Adw.EntryRow(title=title)
+    return CompatEntryRow(title=title)
+
+
+def make_switch_row(title: str) -> Gtk.Widget:
+    if hasattr(Adw, "SwitchRow"):
+        return Adw.SwitchRow(title=title)
+    return CompatSwitchRow(title=title)
+
+
+def connect_switch_row_active(row: Gtk.Widget, callback: Callable[..., None]) -> None:
+    if hasattr(row, "connect_active_notify"):
+        row.connect_active_notify(callback)  # type: ignore[attr-defined]
+    else:
+        row.connect("notify::active", callback)
+
+
 # ── Settings Dialog ─────────────────────────────────────────────
 class SettingsWindow(Adw.Window):
     """Preferences dialog using libadwaita widgets."""
@@ -201,7 +281,7 @@ class SettingsWindow(Adw.Window):
         self.set_modal(True)
         self.set_default_size(480, -1)
 
-        toolbar_view = Adw.ToolbarView()
+        toolbar_view = make_toolbar_view()
 
         header = Adw.HeaderBar()
         cancel_btn = Gtk.Button(label="Annulla")
@@ -222,11 +302,11 @@ class SettingsWindow(Adw.Window):
             "locale di Bottles usata per l'installazione."
         )
 
-        self.server_row = Adw.EntryRow(title="Indirizzo server")
+        self.server_row = make_entry_row("Indirizzo server")
         self.server_row.set_text(config.server_url)
         group.add(self.server_row)
 
-        self.bottles_row = Adw.EntryRow(title="Cartella Bottles")
+        self.bottles_row = make_entry_row("Cartella Bottles")
         self.bottles_row.set_text(config.bottles_dir)
         group.add(self.bottles_row)
 
@@ -444,9 +524,9 @@ class CellarWindow(Adw.ApplicationWindow):
         self.bottles_info_row.add_css_class("property")
         info_group.add(self.bottles_info_row)
 
-        self.replace_row = Adw.SwitchRow(title="Sostituisci installazioni esistenti")
+        self.replace_row = make_switch_row("Sostituisci installazioni esistenti")
         self.replace_row.set_active(self.config.replace_existing)
-        self.replace_row.connect("notify::active", self._store_replace_preference)
+        connect_switch_row_active(self.replace_row, self._store_replace_preference)
         info_group.add(self.replace_row)
 
         content_box.append(info_group)
@@ -492,7 +572,7 @@ class CellarWindow(Adw.ApplicationWindow):
         self.toast_overlay.set_child(outer_box)
 
         # ── ToolbarView ──
-        toolbar_view = Adw.ToolbarView()
+        toolbar_view = make_toolbar_view()
         toolbar_view.add_top_bar(header)
         toolbar_view.set_content(self.toast_overlay)