feat(ui): AI components (#2058)

* feat(ui): ai assistant components

* chore: update CHANGELOG.md

* chore: fix lints

* test: add tests

* chore: fix lints

packages/stream_chat_flutter/CHANGELOG.md

@@ -1,9 +1,14 @@
 ## Upcoming
 
+✅ Added
+
+- Added several new widgets to enhance the AI assistant features.
+  - `StreamingMessageView` to show AI assistant messages with streaming animation.
+  - `AITypingIndicatorView` to show AI typing indicator.
+
 🐞 Fixed
 
-- [[#2030]](https://github.com/GetStream/stream-chat-flutter/issues/2030) Fixed `video_thumbnail`
-  Namespace not specified.
+- [[#2030]](https://github.com/GetStream/stream-chat-flutter/issues/2030) Fixed `video_thumbnail` Namespace not specified.
 
 ## 8.2.0
 

packages/stream_chat_flutter/lib/src/ai_assistant/ai_typing_indicator_view.dart

@@ -0,0 +1,204 @@
+import 'package:flutter/material.dart';
+import 'package:stream_chat_flutter/src/utils/extensions.dart';
+
+/// {@template aiTypingIndicatorView}
+/// A widget that displays a typing indicator for the AI.
+///
+/// This widget is used to indicate the various states of the AI such as
+/// [AI_STATE_THINKING], [AI_STATE_CHECKING_SOURCES] etc.
+///
+/// The widget displays a text and a series of animated dots.
+///
+/// ```dart
+/// AITypingIndicatorView(
+///  text: 'AI is thinking',
+/// );
+/// ```
+///
+/// see also:
+/// - [AnimatedDots] which is used to display the animated dots.
+/// {@endtemplate}
+class AITypingIndicatorView extends StatelessWidget {
+  /// {@macro aiTypingIndicatorView}
+  const AITypingIndicatorView({
+    super.key,
+    required this.text,
+    this.textStyle,
+    this.dotColor,
+    this.dotCount = 3,
+    this.dotSize = 8,
+  });
+
+  /// The text to display in the widget.
+  ///
+  /// Typically this is the state of the AI such as "AI is thinking",
+  final String text;
+
+  /// The style to use for the text.
+  ///
+  /// If not provided, the default text style is used.
+  final TextStyle? textStyle;
+
+  /// The color of the animated dots displayed next to the text.
+  ///
+  /// If not provided, the color of the [textStyle] is used if available or
+  /// [Colors.black] is used.
+  final Color? dotColor;
+
+  /// The number of animated dots to display next to the text.
+  ///
+  /// Defaults to 3.
+  final int dotCount;
+
+  /// The size of the animated dots displayed next to the text.
+  ///
+  /// Defaults to 8.
+  final double dotSize;
+
+  @override
+  Widget build(BuildContext context) {
+    return Row(
+      mainAxisSize: MainAxisSize.min,
+      children: [
+        Text(text, style: textStyle),
+        const SizedBox(width: 8),
+        AnimatedDots(
+          size: dotSize,
+          count: dotCount,
+          color: dotColor ?? textStyle?.color ?? Colors.black,
+        ),
+      ],
+    );
+  }
+}
+
+/// {@template animatedDots}
+/// A widget that displays a series of animated dots.
+///
+/// The dots are animated to scale up and down in size and fade in and out in
+/// opacity.
+///
+/// The widget is typically used to indicate that someone is typing.
+/// {@endtemplate}
+class AnimatedDots extends StatelessWidget {
+  /// {@macro animatedDots}
+  const AnimatedDots({
+    super.key,
+    this.count = 3,
+    this.size = 8,
+    this.spacing = 4,
+    this.color = Colors.black,
+  });
+
+  /// The number of dots to display.
+  ///
+  /// Defaults to 3.
+  final int count;
+
+  /// The size of each dot.
+  ///
+  /// Defaults to 8.
+  final double size;
+
+  /// The spacing between each dot.
+  ///
+  /// Defaults to 4.
+  final double spacing;
+
+  /// The color of the dots.
+  ///
+  /// Defaults to [Colors.black].
+  final Color color;
+
+  @override
+  Widget build(BuildContext context) {
+    return Row(
+      mainAxisSize: MainAxisSize.min,
+      children: <Widget>[
+        ...List.generate(
+          count,
+          (index) => _AnimatedDot(
+            key: ValueKey(index),
+            index: index,
+            size: size,
+            color: color,
+          ),
+        ),
+      ].insertBetween(const SizedBox(width: 4)),
+    );
+  }
+}
+
+class _AnimatedDot extends StatefulWidget {
+  const _AnimatedDot({
+    super.key,
+    required this.index,
+    this.size = 8,
+    this.color = Colors.black,
+  });
+
+  final int index;
+  final double size;
+  final Color color;
+
+  @override
+  State<_AnimatedDot> createState() => _AnimatedDotState();
+}
+
+class _AnimatedDotState extends State<_AnimatedDot>
+    with SingleTickerProviderStateMixin<_AnimatedDot> {
+  late final AnimationController _repeatingController;
+
+  @override
+  void initState() {
+    super.initState();
+    _repeatingController = AnimationController(
+      vsync: this,
+      duration: const Duration(milliseconds: 800),
+    )..addStatusListener(
+        (status) {
+          if (status == AnimationStatus.completed) {
+            if (mounted) _repeatingController.reverse();
+          } else if (status == AnimationStatus.dismissed) {
+            if (mounted) _repeatingController.forward();
+          }
+        },
+      );
+
+    Future.delayed(
+      Duration(milliseconds: 200 * widget.index),
+      () {
+        if (mounted) _repeatingController.forward();
+      },
+    );
+  }
+
+  @override
+  void dispose() {
+    _repeatingController.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final animation = CurvedAnimation(
+      parent: _repeatingController,
+      curve: Curves.easeInOut,
+    );
+
+    return ScaleTransition(
+      scale: Tween<double>(begin: 0.5, end: 1).animate(animation),
+      child: FadeTransition(
+        opacity: Tween<double>(begin: 0.3, end: 1).animate(animation),
+        child: Container(
+          width: widget.size,
+          height: widget.size,
+          decoration: BoxDecoration(
+            color: widget.color,
+            shape: BoxShape.circle,
+          ),
+        ),
+      ),
+    );
+  }
+}