fix: Top app bar icon color

refactor: Add themeMode extensions
refactor: Create theme service data class

lib/src/components/top_app_bar/extended_top_app_bar.dart

@@ -49,33 +49,36 @@ class ZetaExtendedAppBarDelegate extends SliverPersistentHeaderDelegate {
       constraints: BoxConstraints(minHeight: Zeta.of(context).spacing.xl_9, maxHeight: maxExtent),
       child: ColoredBox(
         color: Zeta.of(context).colors.surfaceDefault,
-        child: Stack(
-          children: [
-            Positioned(
-              top: shrinks
-                  ? (topMax + (-1 * shrinkOffset)).clamp(
-                      topMin -
-                          (searchController != null && searchController!.isEnabled
-                              ? searchBarOffsetTop
-                              : Zeta.of(context).spacing.none),
-                      topMax,
-                    )
-                  : topMax,
-              left: shrinks ? ((shrinkOffset / maxExtent) * _maxExtent).clamp(leftMin, leftMax) : leftMin,
-              right: searchController != null && searchController!.isEnabled
-                  ? searchBarOffsetRight
-                  : Zeta.of(context).spacing.none,
-              child: title,
-            ),
-            if (leading != null)
-              Positioned(top: Zeta.of(context).spacing.medium, left: Zeta.of(context).spacing.small, child: leading!),
-            if (actions != null)
+        child: IconTheme(
+          data: IconThemeData(color: Zeta.of(context).colors.mainDefault),
+          child: Stack(
+            children: [
               Positioned(
-                top: Zeta.of(context).spacing.medium,
-                right: Zeta.of(context).spacing.small,
-                child: Row(children: actions!),
+                top: shrinks
+                    ? (topMax + (-1 * shrinkOffset)).clamp(
+                        topMin -
+                            (searchController != null && searchController!.isEnabled
+                                ? searchBarOffsetTop
+                                : Zeta.of(context).spacing.none),
+                        topMax,
+                      )
+                    : topMax,
+                left: shrinks ? ((shrinkOffset / maxExtent) * _maxExtent).clamp(leftMin, leftMax) : leftMin,
+                right: searchController != null && searchController!.isEnabled
+                    ? searchBarOffsetRight
+                    : Zeta.of(context).spacing.none,
+                child: title,
               ),
-          ],
+              if (leading != null)
+                Positioned(top: Zeta.of(context).spacing.medium, left: Zeta.of(context).spacing.small, child: leading!),
+              if (actions != null)
+                Positioned(
+                  top: Zeta.of(context).spacing.medium,
+                  right: Zeta.of(context).spacing.small,
+                  child: Row(children: actions!),
+                ),
+            ],
+          ),
         ),
       ),
     );

lib/src/theme/color_extensions.dart

@@ -1,4 +1,5 @@
 import 'dart:math' as math;
+import 'dart:ui';
 
 import 'package:flutter/material.dart';
 import '../../zeta_flutter.dart';
@@ -343,3 +344,17 @@ extension ZetaSemanticColorExtension on ZetaSemanticColors {
         onSurface: mainDefault,
       );
 }
+
+/// Extensions on [ThemeMode] to provide additional functionality.
+extension ZetaThemeModeExtension on ThemeMode {
+  /// Returns true if the theme mode is dark.
+  bool get isDark =>
+      this == ThemeMode.system ? PlatformDispatcher.instance.platformBrightness.isDark : this == ThemeMode.dark;
+
+  /// Returns the brightness value based on the theme mode.
+  Brightness get brightness => isDark ? Brightness.dark : Brightness.light;
+}
+
+extension on Brightness {
+  bool get isDark => this == Brightness.dark;
+}

lib/src/theme/theme_service.dart

@@ -6,6 +6,28 @@ import 'contrast.dart';
 const String _kThemeMode = 'themeMode';
 const String _kContrast = 'contrast';
 const String _kThemeId = 'theme_id';
+const String _kFontFamily = 'fontFamily';
+
+/// `ZetaThemeData` is a class that holds the theme data to be stored with the theme service.
+class ZetaThemeServiceData {
+  /// Constructs a [ZetaThemeServiceData].
+  ///
+  /// All fields are optional. If null, defaults will be used.
+  ZetaThemeServiceData({this.themeId, this.themeMode, this.contrast, this.fontFamily});
+
+  /// The unique identifier for the custom theme data.
+  final String? themeId;
+
+  /// The theme mode of the Zeta theme.
+  final ThemeMode? themeMode;
+
+  /// The contrast of the Zeta theme.
+  final ZetaContrast? contrast;
+
+  /// The font family of the Zeta theme.
+  final String? fontFamily;
+}
+
 // TODO(colors): Re-add custom font somewhere (not here)
 // TODO(colors): Add tests
 /// `ZetaThemeService` is an abstract class.
@@ -27,8 +49,8 @@ abstract class ZetaThemeService {
   ///
   /// `ZetaContrast` defines different contrast styles to use across the application.
   ///
-  /// Returns a Future `(ZetaThemeData?, ThemeMode?, ZetaContrast?)`.
-  Future<(ThemeMode?, ZetaContrast?, String?)> loadTheme();
+  /// Returns a Future [ZetaThemeServiceData].
+  Future<ZetaThemeServiceData> loadTheme();
 
   /// Saves the provided theme data as the application's theme.
   ///
@@ -38,11 +60,7 @@ abstract class ZetaThemeService {
   ///
   /// Returns a `Future` that completes when the theme data has been successfully saved.
 
-  Future<void> saveTheme({
-    required ThemeMode themeMode,
-    required ZetaContrast contrast,
-    required String? themeId,
-  });
+  Future<void> saveTheme({required ZetaThemeServiceData themeData});
 }
 
 /// A default implementation of `ZetaThemeService` that uses `SharedPreferences` to store the theme data.
@@ -51,7 +69,7 @@ class ZetaDefaultThemeService extends ZetaThemeService {
   const ZetaDefaultThemeService();
 
   @override
-  Future<(ThemeMode?, ZetaContrast?, String?)> loadTheme() async {
+  Future<ZetaThemeServiceData> loadTheme() async {
     final preferences = await SharedPreferences.getInstance();
 
     final modeString = preferences.getString(_kThemeMode);
@@ -66,21 +84,33 @@ class ZetaDefaultThemeService extends ZetaThemeService {
     final contrast = contrastString == ZetaContrast.aaa.name ? ZetaContrast.aaa : ZetaContrast.aa;
 
     final themeId = preferences.getString(_kThemeId);
-
-    return (themeMode, contrast, themeId);
+    final fontFamily = preferences.getString(_kFontFamily);
+
+    return ZetaThemeServiceData(
+      themeMode: themeMode,
+      contrast: contrast,
+      themeId: themeId,
+      fontFamily: fontFamily,
+    );
   }
 
   @override
-  Future<void> saveTheme({
-    required ThemeMode themeMode,
-    required ZetaContrast contrast,
-    required String? themeId,
-  }) async {
+  Future<void> saveTheme({required ZetaThemeServiceData themeData}) async {
     final preferences = await SharedPreferences.getInstance();
-
-    await preferences.setString(_kThemeMode, themeMode.name);
-    await preferences.setString(_kContrast, contrast.name);
-
-    if (themeId != null) await preferences.setString(_kThemeId, themeId);
+    final List<Future<void>> futures = [];
+
+    if (themeData.fontFamily != null) {
+      futures.add(preferences.setString(_kFontFamily, themeData.fontFamily!));
+    }
+    if (themeData.themeMode != null) {
+      futures.add(preferences.setString(_kThemeMode, themeData.themeMode!.name));
+    }
+    if (themeData.contrast != null) {
+      futures.add(preferences.setString(_kContrast, themeData.contrast!.name));
+    }
+    if (themeData.themeId != null) {
+      futures.add(preferences.setString(_kThemeId, themeData.themeId!));
+    }
+    await Future.wait(futures);
   }
 }

lib/src/utils/zeta.dart

@@ -1,6 +1,5 @@
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
-import 'package:flutter/scheduler.dart';
 
 import '../../zeta_flutter.dart';
 
@@ -66,16 +65,7 @@ class Zeta extends InheritedWidget {
   /// If the theme mode is set to 'system', it will return the brightness that ties with the device's system theme setting.
   /// If the theme mode is set to 'light', it always returns `Brightness.light`.
   /// If neither, it returns `Brightness.dark` by default (i.e., when the theme mode is 'dark').
-  Brightness get brightness {
-    if (themeMode == ThemeMode.system) {
-      return SchedulerBinding
-          .instance.platformDispatcher.platformBrightness; // Return the current system brightness setting
-    } else if (themeMode == ThemeMode.light) {
-      return Brightness.light; // Return the light mode brightness
-    } else {
-      return Brightness.dark; // Default: Return the dark mode brightness
-    }
-  }
+  Brightness get brightness => themeMode.brightness;
 
   /// Gets the radius values based on the tokens.
   ZetaRadiiSemantics get radius => semantics.radii;

lib/src/utils/zeta_provider.dart

@@ -172,15 +172,15 @@ class ZetaProviderState extends State<ZetaProvider> with Diagnosticable, Widgets
 
   /// Retrieves the theme values from the shared preferences.
   Future<void> getThemeValuesFromPreferences() async {
-    final (themeMode, contrast, themeId) = await widget.themeService.loadTheme();
+    final ZetaThemeServiceData themeServiceData = await widget.themeService.loadTheme();
 
     // Set the initial theme mode.
-    _themeMode = themeMode ?? widget.initialThemeMode ?? ThemeMode.system;
+    _themeMode = themeServiceData.themeMode ?? widget.initialThemeMode ?? ThemeMode.system;
 
     // Set the initial contrast.
-    _contrast = contrast ?? widget.initialContrast ?? ZetaContrast.aa;
+    _contrast = themeServiceData.contrast ?? widget.initialContrast ?? ZetaContrast.aa;
 
-    final loadedTheme = _customThemes[widget.initialTheme ?? themeId];
+    final loadedTheme = _customThemes[themeServiceData.themeId ?? widget.initialTheme];
 
     if (loadedTheme != null) {
       _customTheme = loadedTheme;
@@ -319,9 +319,11 @@ class ZetaProviderState extends State<ZetaProvider> with Diagnosticable, Widgets
   void _saveThemeChange() {
     unawaited(
       widget.themeService.saveTheme(
-        themeMode: _themeMode,
-        contrast: _contrast,
-        themeId: _customTheme?.id,
+        themeData: ZetaThemeServiceData(
+          themeMode: _themeMode,
+          contrast: _contrast,
+          themeId: _customTheme?.id,
+        ),
       ),
     );
   }
@@ -356,7 +358,6 @@ class _InternalProvider extends StatefulWidget {
   /// Represents the late initialization of the ZetaContrast value.
   final ZetaContrast contrast;
 
-  /// Represents the late initialization of the ThemeMode value.
   final ThemeMode themeMode;
 
   final bool rounded;
@@ -389,14 +390,14 @@ class _InternalProviderState extends State<_InternalProvider> {
       themeMode: widget.themeMode,
       contrast: widget.contrast,
       rounded: widget.rounded,
-      customPrimitives: widget.themeMode == ThemeMode.light
-          ? ZetaPrimitivesLight(
-              primary: widget.customTheme?.primary,
-              secondary: widget.customTheme?.secondary,
-            )
-          : ZetaPrimitivesDark(
+      customPrimitives: widget.themeMode.isDark
+          ? ZetaPrimitivesDark(
               primary: widget.customTheme?.primaryDark,
               secondary: widget.customTheme?.secondaryDark,
+            )
+          : ZetaPrimitivesLight(
+              primary: widget.customTheme?.primary,
+              secondary: widget.customTheme?.secondary,
             ),
       child: Builder(
         builder: (context) {