import 'dart:async';

import 'package:clide/builtin/decisions/src/decision_colors.dart';
import 'package:clide/builtin/shared/reader_chrome.dart';
import 'package:clide/kernel/kernel.dart';
import 'package:clide/widgets/widgets.dart';
import 'package:flutter/widgets.dart';

class DecisionDetailView extends StatefulWidget {
  const DecisionDetailView({super.key, this.initialId});
  final String? initialId;

  @override
  State<DecisionDetailView> createState() => _DecisionDetailViewState();
}

class _DecisionDetailViewState extends State<DecisionDetailView> {
  Map<String, Object?>? _decision;
  bool _loading = false;
  StreamSubscription<Message>? _sub;
  ReaderNav? _nav;

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    if (_sub != null) return;
    final kernel = ClideKernel.of(context);
    // The back/forward history is the retained right-pane nav (T-196):
    // it records selections (even before this view mounts) and re-emits
    // them on the single 'load' channel this view loads from.
    _nav = kernel.readerNav.navFor('builtin.decisions', dataKey: 'id')..addListener(_onNavChanged);
    _sub = kernel.messages.subscribe(publisher: 'builtin.decisions', channel: 'load').listen((msg) {
      final id = msg.data['id'] as String?;
      if (id != null) unawaited(_load(id));
    });
    // Grab the latest entry the nav already holds — the selection that
    // revealed this tab arrived before we could subscribe to 'load'.
    final current = _nav!.current ?? widget.initialId;
    if (current != null) unawaited(_load(current));
  }

  void _onNavChanged() {
    if (mounted) setState(() {}); // refresh action-bar button state (pin, etc.)
  }

  @override
  void dispose() {
    _sub?.cancel();
    _nav?.removeListener(_onNavChanged);
    super.dispose();
  }

  /// Fetch + display [id]. History lives in [ReaderNav]; this never pushes.
  Future<void> _load(String id) async {
    setState(() => _loading = true);
    final kernel = ClideKernel.of(context);
    final resp = await kernel.ipc.request('pql.decisions.read', args: {'id': id});
    if (!mounted) return;
    if (resp.ok) {
      kernel.messages.publish('builtin.decisions', 'focus', {'id': id});
    }
    setState(() {
      _loading = false;
      _decision = resp.ok ? resp.data : null;
    });
  }

  void _onBack() => _nav?.back();
  void _onForward() => _nav?.forward();
  void _onPin() => _nav?.togglePin();
  void _onJumpToPin() => _nav?.jumpToPin();

  void _onEdit() {
    final filePath = _decision?['file_path'] as String?;
    if (filePath == null) return;
    final kernel = ClideKernel.of(context);
    unawaited(kernel.ipc.request('editor.open', args: {'path': filePath}));
  }

  void _navigateToRecord(BuildContext context, String id) {
    final kernel = ClideKernel.of(context);
    if (id.startsWith('T-')) {
      kernel.messages.publish('builtin.tickets', 'selection', {'id': id});
    } else {
      kernel.messages.publish('builtin.decisions', 'selection', {'id': id});
    }
  }

  @override
  Widget build(BuildContext context) {
    if (_loading) {
      return Center(
        child: ClideText(ClideSettings.i18n.string(context, 'detail.loading', namespace: 'builtin.decisions', placeholder: 'Loading…'), muted: true),
      );
    }
    final d = _decision;
    if (d == null) {
      return Padding(
        padding: const EdgeInsets.all(12),
        child: ClideText(
          ClideSettings.i18n.string(context, 'detail.empty', namespace: 'builtin.decisions', placeholder: 'Select a decision to view details.'),
          muted: true,
        ),
      );
    }

    final tokens = ClideSettings.theme.of(context).surface;
    final isDark = ClideSettings.theme.of(context).dark;
    final typeColors = DecisionTypeColors.forTheme(dark: isDark);

    final id = d['id'] as String? ?? '';
    final title = d['title'] as String? ?? '';
    final type = d['type'] as String?;
    final domain = d['domain'] as String?;
    final status = d['status'] as String?;
    final date = d['date'] as String?;
    final body = d['body'] as String?;
    final refs = (d['refs'] as List?)?.cast<Map<String, Object?>>() ?? const [];
    final typeColor = typeColors.forType(type);
    final filePath = d['file_path'] as String?;

    return ClidePaneChrome(
      title: id,
      subtitle: title,
      leading: ReaderPinButton(pinned: _nav?.hasPinned ?? false, onTap: _decision != null ? _onPin : null),
      trailing: [
        ReaderActionBar(
          canGoBack: _nav?.canGoBack ?? false,
          canGoForward: _nav?.canGoForward ?? false,
          hasPinned: _nav?.hasPinned ?? false,
          onBack: (_nav?.canGoBack ?? false) ? _onBack : null,
          onForward: (_nav?.canGoForward ?? false) ? _onForward : null,
          onJumpToPin: (_nav?.hasPinned ?? false) ? _onJumpToPin : null,
          onEdit: filePath != null ? _onEdit : null,
        ),
      ],
      child: SingleChildScrollView(
        padding: const EdgeInsets.all(12),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            Container(
              padding: const EdgeInsets.all(12),
              decoration: BoxDecoration(
                color: tokens.panelBackground,
                borderRadius: BorderRadius.circular(4),
                border: Border.all(color: tokens.panelBorder),
              ),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Row(
                    children: [
                      ClideTooltip(
                        message: type ?? 'confirmed',
                        child: Container(
                          width: 10,
                          height: 10,
                          decoration: BoxDecoration(color: typeColor, shape: BoxShape.circle),
                        ),
                      ),
                      const SizedBox(width: 8),
                      ClideText(id, fontSize: clideFontSmall, color: typeColor, fontFamily: ClideSettings.fonts.monoOf(context)),
                      const Spacer(),
                      if (domain != null)
                        Container(
                          padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
                          decoration: BoxDecoration(color: tokens.panelBorder, borderRadius: BorderRadius.circular(3)),
                          child: ClideText(domain, fontSize: clideFontBadge, color: tokens.globalTextMuted, fontFamily: ClideSettings.fonts.monoOf(context)),
                        ),
                    ],
                  ),
                  const SizedBox(height: 8),
                  ClideText(title, fontSize: 15, fontWeight: FontWeight.w500),
                  if (date != null) ...[
                    const SizedBox(height: 6),
                    ClideText(date, muted: true, fontSize: clideFontSmall, fontFamily: ClideSettings.fonts.monoOf(context)),
                  ],
                  if (status != null && status != 'active') ...[const SizedBox(height: 8), _StatusBadge(status: status, tokens: tokens)],
                ],
              ),
            ),
            if (body != null && body.isNotEmpty) ...[const SizedBox(height: 12), ClideMarkdown(body, onRecordTap: (id) => _navigateToRecord(context, id))],
            if (refs.isNotEmpty) ...[
              const SizedBox(height: 16),
              ClideText(
                ClideSettings.i18n.string(context, 'detail.section.refs', namespace: 'builtin.decisions', placeholder: 'CROSS-REFERENCES'),
                fontSize: clideFontSmall,
                color: tokens.sidebarSectionHeader,
                fontFamily: ClideSettings.fonts.monoOf(context),
              ),
              const SizedBox(height: 6),
              for (final ref in refs) _RefCard(ref: ref, tokens: tokens),
            ],
          ],
        ),
      ),
    );
  }
}

class _RefCard extends StatelessWidget {
  const _RefCard({required this.ref, required this.tokens});
  final Map<String, Object?> ref;
  final SurfaceTokens tokens;

  @override
  Widget build(BuildContext context) {
    final targetId = (ref['target_id'] ?? ref['source_id']) as String? ?? '';
    final refType = ref['ref_type'] as String? ?? '';
    return Padding(
      padding: const EdgeInsets.only(bottom: 4),
      child: ClideTappable(
        onTap: () => ClideKernel.of(context).messages.publish('builtin.decisions', 'selection', {'id': targetId}),
        builder: (ctx, hovered, _) => Container(
          padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 6),
          decoration: BoxDecoration(
            color: hovered ? tokens.sidebarItemHover : tokens.panelBackground,
            borderRadius: BorderRadius.circular(4),
            border: Border.all(color: hovered ? tokens.panelActiveBorder : tokens.panelBorder),
          ),
          child: Row(
            children: [
              ClideText(targetId, fontSize: clideFontSmall, color: tokens.globalFocus, fontFamily: ClideSettings.fonts.monoOf(context)),
              const SizedBox(width: 8),
              ClideText(refType, fontSize: clideFontSmall, color: tokens.globalTextMuted),
            ],
          ),
        ),
      ),
    );
  }
}

class _StatusBadge extends StatelessWidget {
  const _StatusBadge({required this.status, required this.tokens});
  final String status;
  final SurfaceTokens tokens;

  @override
  Widget build(BuildContext context) {
    final color = switch (status) {
      'open' => tokens.statusWarning,
      'resolved' => tokens.statusSuccess,
      _ => tokens.globalTextMuted,
    };
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
      decoration: BoxDecoration(color: color.withAlpha(0x30), borderRadius: BorderRadius.circular(3)),
      child: ClideText(status.toUpperCase(), fontSize: clideFontBadge, color: color, fontFamily: ClideSettings.fonts.monoOf(context)),
    );
  }
}