chore: update ChannelListHeaderTheme

packages/stream_chat_flutter/lib/src/theme/channel_list_header_theme.dart

@@ -1,17 +1,63 @@
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
+import 'package:stream_chat_flutter/src/stream_chat_theme.dart';
 import 'package:stream_chat_flutter/src/theme/avatar_theme.dart';
 
-/// Theme dedicated to the [ChannelListHeader]
-class ChannelListHeaderTheme {
-  /// Returns a new [ChannelListHeaderTheme]
+/// Overrides the default style of [ChannelListHeader] descendants.
+///
+/// See also:
+///
+///  * [ChannelListHeaderThemeData], which is used to configure this theme.
+class ChannelListHeaderTheme extends InheritedTheme {
+  /// Creates a [ChannelListHeaderTheme].
+  ///
+  /// The [data] parameter must not be null.
   const ChannelListHeaderTheme({
-    this.title,
+    Key? key,
+    required this.data,
+    required Widget child,
+  }) : super(key: key, child: child);
+
+  /// The configuration of this theme.
+  final ChannelListHeaderThemeData data;
+
+  /// The closest instance of this class that encloses the given context.
+  ///
+  /// If there is no enclosing [ChannelListHeaderTheme] widget, then
+  /// [StreamChatThemeData.channelListHeaderTheme] is used.
+  ///
+  /// Typical usage is as follows:
+  ///
+  /// ```dart
+  /// final theme = ChannelListHeaderTheme.of(context);
+  /// ```
+  static ChannelListHeaderThemeData of(BuildContext context) {
+    final channelListHeaderTheme =
+        context.dependOnInheritedWidgetOfExactType<ChannelListHeaderTheme>();
+    return channelListHeaderTheme?.data ??
+        StreamChatTheme.of(context).channelListHeaderTheme;
+  }
+
+  @override
+  Widget wrap(BuildContext context, Widget child) =>
+      ChannelListHeaderTheme(data: data, child: child);
+
+  @override
+  bool updateShouldNotify(ChannelListHeaderTheme oldWidget) =>
+      data != oldWidget.data;
+}
+
+/// Theme dedicated to the [ChannelListHeader]
+class ChannelListHeaderThemeData with Diagnosticable {
+  /// Returns a new [ChannelListHeaderThemeData]
+  const ChannelListHeaderThemeData({
+    this.titleStyle,
     this.avatarTheme,
     this.color,
   });
 
   /// Style of the title text
-  final TextStyle? title;
+  final TextStyle? titleStyle;
 
   /// Theme dedicated to the userAvatar
   final AvatarThemeData? avatarTheme;
@@ -19,25 +65,61 @@ class ChannelListHeaderTheme {
   /// Background color of the appbar
   final Color? color;
 
-  /// Returns a new [ChannelListHeaderTheme] replacing some of its properties
-  ChannelListHeaderTheme copyWith({
-    TextStyle? title,
+  /// Returns a new [ChannelListHeaderThemeData] replacing some of its
+  /// properties
+  ChannelListHeaderThemeData copyWith({
+    TextStyle? titleStyle,
     AvatarThemeData? avatarTheme,
     Color? color,
   }) =>
-      ChannelListHeaderTheme(
-        title: title ?? this.title,
+      ChannelListHeaderThemeData(
+        titleStyle: titleStyle ?? this.titleStyle,
         avatarTheme: avatarTheme ?? this.avatarTheme,
         color: color ?? this.color,
       );
 
-  /// Merges [this] [ChannelListHeaderTheme] with the [other]
-  ChannelListHeaderTheme merge(ChannelListHeaderTheme? other) {
+  /// Linearly interpolate from one [ChannelListHeaderThemeData] to another.
+  ChannelListHeaderThemeData lerp(
+    ChannelListHeaderThemeData a,
+    ChannelListHeaderThemeData b,
+    double t,
+  ) =>
+      ChannelListHeaderThemeData(
+        avatarTheme:
+            const AvatarThemeData().lerp(a.avatarTheme!, b.avatarTheme!, t),
+        color: Color.lerp(a.color, b.color, t),
+        titleStyle: TextStyle.lerp(a.titleStyle, b.titleStyle, t),
+      );
+
+  /// Merges [this] [ChannelListHeaderThemeData] with the [other]
+  ChannelListHeaderThemeData merge(ChannelListHeaderThemeData? other) {
     if (other == null) return this;
     return copyWith(
-      title: title?.merge(other.title) ?? other.title,
+      titleStyle: titleStyle?.merge(other.titleStyle) ?? other.titleStyle,
       avatarTheme: avatarTheme?.merge(other.avatarTheme) ?? other.avatarTheme,
       color: other.color,
     );
   }
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      other is ChannelListHeaderThemeData &&
+          runtimeType == other.runtimeType &&
+          titleStyle == other.titleStyle &&
+          avatarTheme == other.avatarTheme &&
+          color == other.color;
+
+  @override
+  int get hashCode =>
+      titleStyle.hashCode ^ avatarTheme.hashCode ^ color.hashCode;
+
+  @override
+  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+    super.debugFillProperties(properties);
+    properties
+      ..add(DiagnosticsProperty('titleStyle', titleStyle))
+      ..add(DiagnosticsProperty('avatarTheme', avatarTheme))
+      ..add(ColorProperty('color', color));
+  }
 }