refactor: optimize renderer

lib/shared/widgets/markdown/streaming_markdown_widget.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:gpt_markdown/gpt_markdown.dart';
 
@@ -5,7 +7,7 @@ import 'markdown_config.dart';
 
 typedef MarkdownLinkTapCallback = void Function(String url, String title);
 
-class StreamingMarkdownWidget extends StatelessWidget {
+class StreamingMarkdownWidget extends StatefulWidget {
   const StreamingMarkdownWidget({
     super.key,
     required this.content,
@@ -17,6 +19,78 @@ class StreamingMarkdownWidget extends StatelessWidget {
   final bool isStreaming;
   final MarkdownLinkTapCallback? onTapLink;
 
+  @override
+  State<StreamingMarkdownWidget> createState() =>
+      _StreamingMarkdownWidgetState();
+}
+
+class _StreamingMarkdownWidgetState extends State<StreamingMarkdownWidget> {
+  late final ValueNotifier<String> _contentNotifier;
+  late String _currentContent;
+  Timer? _debounce;
+  String? _pendingContent;
+
+  @override
+  void initState() {
+    super.initState();
+    _currentContent = widget.content;
+    _contentNotifier = ValueNotifier(widget.content);
+  }
+
+  @override
+  void didUpdateWidget(covariant StreamingMarkdownWidget oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (widget.content == _currentContent) {
+      return;
+    }
+
+    // Coalesce rapid streaming updates so we only rebuild markdown a few times.
+    _pendingContent = widget.content;
+    _debounce ??= Timer(const Duration(milliseconds: 45), () {
+      if (!mounted) {
+        return;
+      }
+      final next = _pendingContent ?? widget.content;
+      _currentContent = next;
+      _contentNotifier.value = next;
+      _pendingContent = null;
+      _debounce = null;
+    });
+  }
+
+  @override
+  void dispose() {
+    _debounce?.cancel();
+    _contentNotifier.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return ValueListenableBuilder<String>(
+      valueListenable: _contentNotifier,
+      builder: (context, value, _) {
+        return _StreamingMarkdownContent(
+          content: value,
+          isStreaming: widget.isStreaming,
+          onTapLink: widget.onTapLink,
+        );
+      },
+    );
+  }
+}
+
+class _StreamingMarkdownContent extends StatelessWidget {
+  const _StreamingMarkdownContent({
+    required this.content,
+    required this.isStreaming,
+    required this.onTapLink,
+  });
+
+  final String content;
+  final bool isStreaming;
+  final MarkdownLinkTapCallback? onTapLink;
+
   @override
   Widget build(BuildContext context) {
     final markdownTheme = ConduitMarkdownConfig.resolve(context);
@@ -38,6 +112,8 @@ class StreamingMarkdownWidget extends StatelessWidget {
         onLinkTap: onTapLink,
         codeBuilder: markdownTheme.codeBuilder,
         imageBuilder: markdownTheme.imageBuilder,
+        components: markdownTheme.blockComponents,
+        inlineComponents: markdownTheme.inlineComponents,
       ),
     );
   }