feat: chat parsing

closes #9

lib/widgets/chat.dart

@@ -8,6 +8,7 @@ import 'package:zap_stream_flutter/rx_filter.dart';
 import 'package:zap_stream_flutter/theme.dart';
 import 'package:zap_stream_flutter/utils.dart';
 import 'package:zap_stream_flutter/widgets/avatar.dart';
+import 'package:zap_stream_flutter/widgets/nostr_text.dart';
 import 'package:zap_stream_flutter/widgets/profile.dart';
 import 'package:zap_stream_flutter/widgets/profile_modal.dart';
 
@@ -291,7 +292,7 @@ class _ChatMessageWidget extends StatelessWidget {
             ),
           ),
           TextSpan(text: " "),
-          TextSpan(text: msg.content, style: TextStyle(color: FONT_COLOR)),
+          ...textToSpans(msg.content, msg.tags, msg.pubKey),
         ],
       ),
     );

lib/widgets/nostr_text.dart

@@ -0,0 +1,108 @@
+import 'package:flutter/gestures.dart';
+import 'package:flutter/material.dart';
+import 'package:go_router/go_router.dart';
+import 'package:ndk/ndk.dart';
+import 'package:ndk/shared/nips/nip19/nip19.dart';
+import 'package:url_launcher/url_launcher.dart';
+import 'package:zap_stream_flutter/theme.dart';
+import 'package:zap_stream_flutter/widgets/profile.dart';
+
+/// Converts a nostr note text containing links
+/// and mentions into multiple spans for rendering
+List<InlineSpan> textToSpans(
+  String content,
+  List<List<String>> tags,
+  String pubkey,
+) {
+  return _buildContentSpans(content);
+}
+
+/// Content parser from camelus
+/// https://github.com/leo-lox/camelus/blob/f58455a0ac07fcc780bdc69b8f4544fd5ea4a46d/lib/presentation_layer/components/note_card/note_card_build_split_content.dart#L262
+List<InlineSpan> _buildContentSpans(String content) {
+  List<InlineSpan> spans = [];
+  RegExp exp = RegExp(
+    r'nostr:(nprofile|npub)[a-zA-Z0-9]+|'
+    r'nostr:(note|nevent)[a-zA-Z0-9]+|'
+    r'(#\$\$\s*[0-9]+\s*\$\$)|'
+    r'(#\w+)|' // Hashtags
+    r'(https?:\/\/(?:www\.)?[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b(?:[-a-zA-Z0-9()@:%_\+.~#?&\/=]*))', // URLs
+    caseSensitive: false,
+  );
+
+  content.splitMapJoin(
+    exp,
+    onMatch: (Match match) {
+      String? matched = match.group(0);
+      if (matched != null) {
+        if (matched.startsWith('nostr:')) {
+          spans.add(_buildProfileOrNoteSpan(matched));
+        } else if (matched.startsWith('#')) {
+          spans.add(_buildHashtagSpan(matched));
+        } else if (matched.startsWith('http')) {
+          spans.add(_buildUrlSpan(matched));
+        }
+      }
+      return '';
+    },
+    onNonMatch: (String text) {
+      spans.add(TextSpan(text: text));
+      return '';
+    },
+  );
+
+  return spans;
+}
+
+InlineSpan _buildProfileOrNoteSpan(String word) {
+  final cleanedWord = word.replaceAll('nostr:', '');
+  final isProfile =
+      cleanedWord.startsWith('nprofile') || cleanedWord.startsWith('npub');
+  final isNote =
+      cleanedWord.startsWith('note') || cleanedWord.startsWith('nevent');
+
+  if (isProfile) {
+    return _inlineMention(Nip19.decode(cleanedWord));
+  }
+  if (isNote) {
+    final eventId = Nip19.decode(cleanedWord);
+    return TextSpan(text: eventId, style: TextStyle(color: PRIMARY_1));
+  } else {
+    return TextSpan(text: word);
+  }
+}
+
+InlineSpan _buildHashtagSpan(String word) {
+  return TextSpan(text: word, style: TextStyle(color: PRIMARY_1));
+}
+
+InlineSpan _buildUrlSpan(String url) {
+  return TextSpan(
+    text: url,
+    style: TextStyle(color: PRIMARY_1),
+    recognizer:
+        TapGestureRecognizer()
+          ..onTap = () {
+            launchUrl(Uri.parse(url));
+          },
+  );
+}
+
+InlineSpan _inlineMention(String pubkey) {
+  return WidgetSpan(
+    alignment: PlaceholderAlignment.middle,
+    child: ProfileLoaderWidget(pubkey, (ctx, profile) {
+      return GestureDetector(
+        onTap:
+            () => ctx.push(
+              "/p/${Nip19.encodePubKey(pubkey)}",
+              extra: profile.data,
+            ),
+        child: Text(
+          "@${ProfileNameWidget.nameFromProfile(profile.data ?? Metadata(pubKey: pubkey))}",
+          style: TextStyle(color: PRIMARY_1),
+        ),
+      );
+    }),
+  );
+}