Moved platform brightness checking from ArcaneApp to ArcaneThemeSwitcher, where it is more appropriate

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

lib/src/arcane_app.dart

@@ -19,7 +19,7 @@ import "package:flutter/material.dart";
 ///   child: MyApp(),
 /// );
 /// ```
-class ArcaneApp extends StatefulWidget {
+class ArcaneApp extends StatelessWidget {
   /// A list of Arcane services that will be made available to the application.
   ///
   /// These services will be provided to the widget tree using
@@ -43,52 +43,15 @@ class ArcaneApp extends StatefulWidget {
     super.key,
   });
 
-  @override
-  State<ArcaneApp> createState() => _ArcaneAppState();
-}
-
-class _ArcaneAppState extends State<ArcaneApp> with WidgetsBindingObserver {
-  final GlobalKey _appKey = GlobalKey();
-
   @override
   Widget build(BuildContext context) {
     return ArcaneEnvironmentProvider(
       child: ArcaneServiceProvider(
-        serviceInstances: widget.services,
+        serviceInstances: services,
         child: ArcaneThemeSwitcher(
-          key: _appKey,
-          child: widget.child,
+          child: child,
         ),
       ),
     );
   }
-
-  @override
-  void initState() {
-    super.initState();
-    // Register as an observer to detect system theme changes
-    WidgetsBinding.instance.addObserver(this);
-  }
-
-  @override
-  void dispose() {
-    // Clean up the observer when the widget is disposed
-    WidgetsBinding.instance.removeObserver(this);
-    super.dispose();
-  }
-
-  @override
-  void didChangePlatformBrightness() {
-    // When system brightness changes, find the current builder context
-    // and use it to check the system theme
-    if (mounted && _appKey.currentContext != null) {
-      // Use the current context from the key to check system theme
-      if (ArcaneReactiveTheme.I.isFollowingSystemTheme) {
-        WidgetsBinding.instance.addPostFrameCallback((_) {
-          ArcaneReactiveTheme.I.followSystemTheme(context);
-        });
-      }
-    }
-    super.didChangePlatformBrightness();
-  }
 }

lib/src/services/reactive_theme/reactive_theme_switcher.dart

@@ -15,13 +15,17 @@ class ArcaneThemeSwitcher extends StatefulWidget {
   State<ArcaneThemeSwitcher> createState() => _ArcaneThemeSwitcherState();
 }
 
-class _ArcaneThemeSwitcherState extends State<ArcaneThemeSwitcher> {
+class _ArcaneThemeSwitcherState extends State<ArcaneThemeSwitcher>
+    with WidgetsBindingObserver {
   late final StreamSubscription<ThemeMode> _themeModeSubscription;
   late final StreamSubscription<ThemeData> _themeSubscription;
 
   @override
   void initState() {
     super.initState();
+    // Register as an observer to detect system theme changes
+    WidgetsBinding.instance.addObserver(this);
+
     _themeModeSubscription = ArcaneReactiveTheme.I.themeModeChanges.listen((_) {
       setState(() {});
     });
@@ -34,6 +38,8 @@ class _ArcaneThemeSwitcherState extends State<ArcaneThemeSwitcher> {
   void dispose() {
     _themeModeSubscription.cancel();
     _themeSubscription.cancel();
+    // Clean up the observer when the widget is disposed
+    WidgetsBinding.instance.removeObserver(this);
     super.dispose();
   }
 
@@ -46,4 +52,19 @@ class _ArcaneThemeSwitcherState extends State<ArcaneThemeSwitcher> {
       child: widget.child,
     );
   }
+
+  @override
+  void didChangePlatformBrightness() {
+    // When system brightness changes, find the current builder context
+    // and use it to check the system theme
+    if (mounted) {
+      // Use the current context from the key to check system theme
+      if (ArcaneReactiveTheme.I.isFollowingSystemTheme) {
+        WidgetsBinding.instance.addPostFrameCallback((_) {
+          ArcaneReactiveTheme.I.followSystemTheme(context);
+        });
+      }
+    }
+    super.didChangePlatformBrightness();
+  }
 }