import 'dart:async';

import 'package:clide/builtin/markdown/src/markdown_viewer.dart';
import 'package:clide/extension/extension.dart';
import 'package:clide/kernel/kernel.dart';
import 'package:clide/widgets/widgets.dart';

class MarkdownExtension extends ClideExtension {
  @override
  String get id => 'builtin.markdown';
  @override
  String get title => 'Markdown';
  @override
  String get version => '0.3.0';
  @override
  List<String> get dependsOn => const [];

  StreamSubscription<Message>? _sub;

  @override
  List<ContributionPoint> get contributions => [
    TabContribution(
      id: 'markdown.viewer',
      slot: Slots.contextPanel,
      title: 'Markdown',
      icon: PhosphorIcons.byName('file-text'),
      build: (_) => const MarkdownViewer(),
    ),
  ];

  @override
  Future<void> activate(ClideExtensionContext ctx) async {
    // Ensure the retained nav exists so it records selections + emits
    // loads whether or not the viewer is mounted (T-196). This handler
    // only reveals the tab; the nav owns load + history.
    ctx.readerNav.navFor(id, dataKey: 'path');
    _sub = ctx.messages.subscribe(publisher: id, channel: 'selection').listen((msg) {
      if (msg.data['path'] is! String) return;
      ctx.panels.activateTab(Slots.contextPanel, 'markdown.viewer');
    });
  }

  @override
  Future<void> deactivate() async => _sub?.cancel();
}