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Client/lib/view/pages/talk/widgets/message_markdown.dart
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Dart

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter_markdown_plus/flutter_markdown_plus.dart';
import '../../../../utils/url_opener.dart';
import '../data/talk_markdown.dart';
/// Renders a Talk chat-message body as Markdown, matching the subset the
/// official Nextcloud Talk clients render.
///
/// Supported (the intentional "Rahmen", kept in sync with Talk's GFM-based
/// renderer): bold, italic, strikethrough, inline code, links (explicit and
/// bare autolinks), headings, ordered/unordered/task lists, fenced code
/// blocks, block quotes, horizontal rules and tables.
///
/// Deliberately unsupported, mirroring Talk's restrictions: raw HTML is shown
/// literally (never interpreted) and images are not fetched/rendered — only
/// their alt text (or URL) is shown, so a message can never pull a remote
/// resource on display.
class MessageMarkdown extends StatelessWidget {
final String data;
final TextStyle? style;
const MessageMarkdown({required this.data, this.style, super.key});
@override
Widget build(BuildContext context) {
final theme = Theme.of(context);
final base =
style ??
theme.textTheme.bodyMedium ??
DefaultTextStyle.of(context).style;
final baseSize = base.fontSize ?? 14;
final muted = (base.color ?? theme.colorScheme.onSurface).withValues(
alpha: 0.55,
);
final codeBackground = theme.colorScheme.surfaceContainerHighest.withValues(
alpha: 0.6,
);
final codeStyle = base.copyWith(
fontFamily: 'monospace',
fontFamilyFallback: const ['monospace'],
fontSize: baseSize * 0.92,
);
final styleSheet = MarkdownStyleSheet.fromTheme(theme).copyWith(
p: base,
a: base.copyWith(
color: Colors.blue,
decoration: TextDecoration.underline,
),
em: base.copyWith(fontStyle: FontStyle.italic),
strong: base.copyWith(fontWeight: FontWeight.bold),
del: base.copyWith(decoration: TextDecoration.lineThrough),
// Talk levels headings down so they stay readable inside a chat bubble;
// we cap them at modest multiples of the body size instead of the theme's
// display sizes.
h1: base.copyWith(fontSize: baseSize * 1.5, fontWeight: FontWeight.bold),
h2: base.copyWith(fontSize: baseSize * 1.4, fontWeight: FontWeight.bold),
h3: base.copyWith(fontSize: baseSize * 1.3, fontWeight: FontWeight.bold),
h4: base.copyWith(fontSize: baseSize * 1.15, fontWeight: FontWeight.bold),
h5: base.copyWith(fontSize: baseSize * 1.05, fontWeight: FontWeight.bold),
h6: base.copyWith(fontWeight: FontWeight.bold),
code: codeStyle.copyWith(backgroundColor: codeBackground),
codeblockPadding: const EdgeInsets.all(8),
codeblockDecoration: BoxDecoration(
color: codeBackground,
borderRadius: BorderRadius.circular(6),
),
blockquote: base.copyWith(color: muted),
blockquotePadding: const EdgeInsets.only(left: 12, top: 2, bottom: 2),
blockquoteDecoration: BoxDecoration(
border: Border(left: BorderSide(color: muted, width: 4)),
),
listBullet: base,
checkbox: base,
horizontalRuleDecoration: BoxDecoration(
border: Border(top: BorderSide(color: muted)),
),
tableHead: base.copyWith(fontWeight: FontWeight.bold),
tableBody: base,
tableBorder: TableBorder.all(color: muted, width: 0.8),
tableCellsPadding: const EdgeInsets.symmetric(
horizontal: 6,
vertical: 3,
),
// Keep multi-block messages compact; the default spacing is too airy for
// a chat bubble.
blockSpacing: baseSize * 0.5,
);
return MarkdownBody(
data: data,
styleSheet: styleSheet,
extensionSet: talkMarkdownExtensionSet,
// Talk turns a single newline into a line break (`breaks: true`);
// standard Markdown would collapse it into a space.
softLineBreak: true,
onTapLink: (text, href, title) {
if (href != null && href.isNotEmpty) unawaited(UrlOpener.openUrl(href));
},
// No remote fetch: render the alt text (or URL) instead of the image.
imageBuilder: (uri, title, alt) => Text(
(alt != null && alt.isNotEmpty) ? alt : uri.toString(),
style: base,
),
checkboxBuilder: (checked) => Padding(
padding: const EdgeInsets.only(right: 4),
child: Icon(
checked ? Icons.check_box_outlined : Icons.check_box_outline_blank,
size: baseSize + 2,
color: base.color,
),
),
);
}
}