part of 'traction.dart';

class TractionPage extends StatefulWidget {
  const TractionPage({
    super.key,
    this.selectionMode = false,
    this.onSelect,
    this.selectedKeys = const {},
  });

  final bool selectionMode;
  final ValueChanged<LocoSummary>? onSelect;
  final Set<String> selectedKeys;

  @override
  State<TractionPage> createState() => _TractionPageState();
}

class _TractionPageState extends State<TractionPage> {
  final _classController = TextEditingController();
  final _classFocusNode = FocusNode();
  final _numberController = TextEditingController();
  final _nameController = TextEditingController();
  bool _mileageFirst = true;
  bool _initialised = false;
  bool _showAdvancedFilters = false;
  String? _selectedClass;
  late Set<String> _selectedKeys;
  String? _lastEventFieldsSignature;
  Timer? _classStatsDebounce;
  bool _showClassStatsPanel = false;
  bool _classStatsLoading = false;
  String? _classStatsError;
  String? _classStatsForClass;
  Map<String, dynamic>? _classStats;

  final Map<String, TextEditingController> _dynamicControllers = {};
  final Map<String, String?> _enumSelections = {};
  bool _restoredFromPrefs = false;

  @override
  void initState() {
    super.initState();
    _classController.addListener(_onClassTextChanged);
  }

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    if (!_initialised) {
      _initialised = true;
      _selectedKeys = {...widget.selectedKeys};
      WidgetsBinding.instance.addPostFrameCallback((_) {
        _initialLoad();
      });
    }
  }

  Future<void> _initialLoad() async {
    final data = context.read<DataService>();
    await _restoreSearchState();
    data.fetchClassList();
    data.fetchEventFields();
    await _refreshTraction();
  }

  @override
  void dispose() {
    _classController.removeListener(_onClassTextChanged);
    _persistSearchState();
    _classController.dispose();
    _classFocusNode.dispose();
    _numberController.dispose();
    _nameController.dispose();
    for (final controller in _dynamicControllers.values) {
      controller.dispose();
    }
    _classStatsDebounce?.cancel();
    super.dispose();
  }

  void _setState(VoidCallback fn) {
    if (!mounted) return;
    // ignore: invalid_use_of_protected_member
    setState(fn);
  }

  bool get _hasFilters {
    final dynamicFieldsUsed =
        _dynamicControllers.values.any(
          (controller) => controller.text.trim().isNotEmpty,
        ) ||
        _enumSelections.values.any(
          (value) => (value ?? '').toString().trim().isNotEmpty,
        );

    return [
          _selectedClass,
          _classController.text,
          _numberController.text,
          _nameController.text,
        ].any((value) => (value ?? '').toString().trim().isNotEmpty) ||
        dynamicFieldsUsed;
  }

  Future<void> _refreshTraction({bool append = false}) async {
    final data = context.read<DataService>();
    final filters = <String, dynamic>{};
    final name = _nameController.text.trim();
    if (name.isNotEmpty) filters['name'] = name;
    _dynamicControllers.forEach((key, controller) {
      final value = controller.text.trim();
      if (value.isNotEmpty) filters[key] = value;
    });
    _enumSelections.forEach((key, value) {
      if (value != null && value.toString().trim().isNotEmpty) {
        filters[key] = value;
      }
    });
    final hadOnly = !_hasFilters;
    await data.fetchTraction(
      hadOnly: hadOnly,
      locoClass: _selectedClass ?? _classController.text.trim(),
      locoNumber: _numberController.text.trim(),
      offset: append ? data.traction.length : 0,
      append: append,
      filters: filters,
      mileageFirst: _mileageFirst,
    );
    await _persistSearchState();
  }

  void _clearFilters() {
    for (final controller in [
      _classController,
      _numberController,
      _nameController,
    ]) {
      controller.clear();
    }
    for (final controller in _dynamicControllers.values) {
      controller.clear();
    }
    _enumSelections.clear();
    setState(() {
      _selectedClass = null;
      _mileageFirst = true;
      _showClassStatsPanel = false;
      _classStats = null;
      _classStatsError = null;
      _classStatsForClass = null;
    });
    _refreshTraction();
  }

  void _onClassTextChanged() {
    if (_selectedClass != null &&
        _classController.text.trim() != (_selectedClass ?? '')) {
      setState(() {
        _selectedClass = null;
      });
    }
    _refreshClassStatsIfOpen();
  }

  List<EventField> _activeEventFields(List<EventField> fields) {
    return fields
        .where(
          (field) => ![
            'class',
            'number',
            'name',
            'build date',
            'build_date',
          ].contains(field.name.toLowerCase()),
        )
        .toList();
  }

  void _syncControllersForFields(List<EventField> fields) {
    final signature = _eventFieldsSignature(fields);
    if (signature == _lastEventFieldsSignature) return;
    _lastEventFieldsSignature = signature;
    _ensureControllersForFields(fields);
  }

  String _eventFieldsSignature(List<EventField> fields) {
    final active = _activeEventFields(fields);
    return active
        .map(
          (field) => [
            field.name,
            field.type ?? '',
            if (field.enumValues != null) field.enumValues!.join('|'),
          ].join('::'),
        )
        .join(';');
  }

  void _ensureControllersForFields(List<EventField> fields) {
    for (final field in fields) {
      if (field.enumValues != null) {
        _enumSelections.putIfAbsent(field.name, () => null);
      } else {
        _dynamicControllers.putIfAbsent(
          field.name,
          () => TextEditingController(),
        );
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final data = context.watch<DataService>();
    final traction = data.traction;
    final classOptions = data.locoClasses;
    final isMobile = MediaQuery.of(context).size.width < 700;
    _syncControllersForFields(data.eventFields);
    final extraFields = _activeEventFields(data.eventFields);

    final slivers = <Widget>[
      SliverPadding(
        padding: const EdgeInsets.fromLTRB(16, 16, 16, 0),
        sliver: SliverList(
          delegate: SliverChildListDelegate(
            [
              Row(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        Text(
                          'Fleet',
                          style: Theme.of(context).textTheme.labelMedium,
                        ),
                        const SizedBox(height: 2),
                        Text(
                          'Traction',
                          style: Theme.of(context).textTheme.headlineSmall,
                        ),
                      ],
                    ),
                  ),
              Row(
                mainAxisSize: MainAxisSize.min,
                children: [
                  IconButton(
                    tooltip: 'Refresh',
                    onPressed: _refreshTraction,
                    icon: const Icon(Icons.refresh),
                  ),
                  if (_hasClassQuery) ...[
                    const SizedBox(width: 8),
                    FilledButton.tonalIcon(
                      onPressed: _toggleClassStatsPanel,
                      icon: Icon(
                        _showClassStatsPanel ? Icons.bar_chart : Icons.insights,
                      ),
                      label: Text(
                        _showClassStatsPanel ? 'Hide class stats' : 'Class stats',
                      ),
                    ),
                  ],
                  const SizedBox(width: 8),
                  FilledButton.icon(
                    onPressed: () async {
                      final createdClass = await context.push<String>(
                        '/traction/new',
                          );
                          if (createdClass != null && createdClass.isNotEmpty) {
                            _classController.text = createdClass;
                            _selectedClass = createdClass;
                            if (mounted) {
                              _refreshTraction();
                            }
                          } else if (mounted && createdClass == '') {
                            _refreshTraction();
                          }
                        },
                        icon: const Icon(Icons.add),
                        label: const Text('New Traction'),
                      ),
                    ],
                  ),
                ],
              ),
              const SizedBox(height: 12),
              Card(
                child: Padding(
                  padding: const EdgeInsets.all(12),
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.stretch,
                    children: [
                      Row(
                        mainAxisAlignment: MainAxisAlignment.spaceBetween,
                        children: [
                          Text(
                            'Filters',
                            style: Theme.of(context).textTheme.titleMedium,
                          ),
                          TextButton(
                            onPressed: _clearFilters,
                            child: const Text('Clear'),
                          ),
                        ],
                      ),
                      const SizedBox(height: 8),
                      Wrap(
                        spacing: 12,
                        runSpacing: 12,
                        children: [
                          SizedBox(
                            width: isMobile ? double.infinity : 240,
                            child: RawAutocomplete<String>(
                              textEditingController: _classController,
                              focusNode: _classFocusNode,
                              optionsBuilder: (TextEditingValue textEditingValue) {
                                final query = textEditingValue.text.toLowerCase();
                                if (query.isEmpty) {
                                  return classOptions;
                                }
                                return classOptions.where(
                                  (c) => c.toLowerCase().contains(query),
                                );
                              },
                              fieldViewBuilder:
                                  (
                                    context,
                                    controller,
                                    focusNode,
                                    onFieldSubmitted,
                                  ) {
                                    return TextField(
                                      controller: controller,
                                      focusNode: focusNode,
                                      decoration: const InputDecoration(
                                        labelText: 'Class',
                                        border: OutlineInputBorder(),
                                      ),
                                      onSubmitted: (_) => _refreshTraction(),
                                    );
                                  },
                              optionsViewBuilder: (context, onSelected, options) {
                                final optionList = options.toList();
                                if (optionList.isEmpty) {
                                  return const SizedBox.shrink();
                                }
                                final maxWidth = isMobile
                                    ? MediaQuery.of(context).size.width - 64
                                    : 240.0;
                                return Align(
                                  alignment: Alignment.topLeft,
                                  child: Material(
                                    elevation: 4,
                                    child: ConstrainedBox(
                                      constraints: BoxConstraints(
                                        maxWidth: maxWidth,
                                        maxHeight: 240,
                                      ),
                                      child: ListView.builder(
                                        padding: EdgeInsets.zero,
                                        shrinkWrap: true,
                                        itemCount: optionList.length,
                                        itemBuilder: (context, index) {
                                          final option = optionList[index];
                                          return ListTile(
                                            title: Text(option),
                                            onTap: () => onSelected(option),
                                          );
                                        },
                                      ),
                                    ),
                                  ),
                                );
                              },
                          onSelected: (String selection) {
                            setState(() {
                              _selectedClass = selection;
                              _classController.text = selection;
                            });
                            _refreshTraction();
                            _refreshClassStatsIfOpen(immediate: true);
                          },
                        ),
                      ),
                          SizedBox(
                            width: isMobile ? double.infinity : 220,
                            child: TextField(
                              controller: _numberController,
                              decoration: const InputDecoration(
                                labelText: 'Number',
                                border: OutlineInputBorder(),
                              ),
                              onSubmitted: (_) => _refreshTraction(),
                            ),
                          ),
                          SizedBox(
                            width: isMobile ? double.infinity : 220,
                            child: TextField(
                              controller: _nameController,
                              decoration: const InputDecoration(
                                labelText: 'Name',
                                border: OutlineInputBorder(),
                              ),
                              onSubmitted: (_) => _refreshTraction(),
                            ),
                          ),
                          FilterChip(
                            label: Text(
                              _mileageFirst ? 'Mileage first' : 'Number order',
                            ),
                            selected: _mileageFirst,
                            onSelected: (v) {
                              setState(() => _mileageFirst = v);
                              _refreshTraction();
                            },
                          ),
                          TextButton.icon(
                            onPressed: () => setState(
                              () => _showAdvancedFilters = !_showAdvancedFilters,
                            ),
                            icon: Icon(
                              _showAdvancedFilters
                                  ? Icons.expand_less
                                  : Icons.expand_more,
                            ),
                            label: Text(
                              _showAdvancedFilters
                                  ? 'Hide filters'
                                  : 'More filters',
                            ),
                          ),
                          ElevatedButton.icon(
                            onPressed: _refreshTraction,
                            icon: const Icon(Icons.search),
                            label: const Text('Search'),
                          ),
                        ],
                      ),
                      AnimatedCrossFade(
                        crossFadeState: _showAdvancedFilters
                            ? CrossFadeState.showFirst
                            : CrossFadeState.showSecond,
                        duration: const Duration(milliseconds: 200),
                        firstChild: Padding(
                          padding: const EdgeInsets.only(top: 12.0),
                          child: data.isEventFieldsLoading
                              ? const Center(
                                  child: Padding(
                                    padding: EdgeInsets.all(8.0),
                                    child: CircularProgressIndicator(
                                      strokeWidth: 2,
                                    ),
                                  ),
                                )
                              : extraFields.isEmpty
                              ? const Text('No extra filters available right now.')
                              : Wrap(
                                  spacing: 12,
                                  runSpacing: 12,
                                  children: extraFields
                                      .map(
                                        (field) => _buildFilterInput(
                                          context,
                                          field,
                                          isMobile,
                                        ),
                                      )
                                      .toList(),
                                ),
                        ),
                        secondChild: const SizedBox.shrink(),
                      ),
                    ],
                  ),
                ),
              ),
              const SizedBox(height: 12),
            ],
          ),
        ),
      ),
      SliverPadding(
        padding: const EdgeInsets.fromLTRB(16, 0, 16, 8),
        sliver: SliverToBoxAdapter(
          child: AnimatedCrossFade(
            crossFadeState: (_showClassStatsPanel && _hasClassQuery)
                ? CrossFadeState.showFirst
                : CrossFadeState.showSecond,
            duration: const Duration(milliseconds: 200),
            firstChild: _buildClassStatsCard(context),
            secondChild: const SizedBox.shrink(),
          ),
        ),
      ),
      SliverPadding(
        padding: const EdgeInsets.fromLTRB(16, 0, 16, 16),
        sliver: _buildTractionSliver(context, data, traction),
      ),
    ];

    final scrollView = RefreshIndicator(
      onRefresh: _refreshTraction,
      child: CustomScrollView(
        physics: const AlwaysScrollableScrollPhysics(),
        slivers: slivers,
      ),
    );

    final content = Stack(
      children: [
        scrollView,
        if (data.isTractionLoading)
          Positioned.fill(
            child: IgnorePointer(
              child: Container(
                color: Theme.of(context).colorScheme.surface.withValues(alpha: 0.6),
                child: const Center(child: CircularProgressIndicator()),
              ),
            ),
          ),
      ],
    );

    if (widget.selectionMode) {
      return Scaffold(
        appBar: AppBar(
          leadingWidth: 56,
          leading: IconButton(
            icon: const Icon(Icons.arrow_back),
            onPressed: () => Navigator.of(context).pop(),
          ),
          title: null,
        ),
        body: content,
      );
    }

    return content;
  }

  bool get _hasClassQuery {
    return (_selectedClass ?? _classController.text).trim().isNotEmpty;
  }

  Future<void> _toggleClassStatsPanel() async {
    if (!_hasClassQuery) return;
    final targetState = !_showClassStatsPanel;
    setState(() {
      _showClassStatsPanel = targetState;
    });
    if (targetState) {
      await _loadClassStats();
    }
  }

  void _refreshClassStatsIfOpen({bool immediate = false}) {
    if (!_showClassStatsPanel || !_hasClassQuery) return;
    final query = (_selectedClass ?? _classController.text).trim();
    if (!immediate && _classStatsForClass == query && _classStats != null) {
      return;
    }
    _classStatsDebounce?.cancel();
    if (immediate) {
      _loadClassStats();
      return;
    }
    _classStatsDebounce = Timer(
      const Duration(milliseconds: 400),
      () {
        if (mounted) _loadClassStats();
      },
    );
  }

  Future<void> _loadClassStats() async {
    final query = (_selectedClass ?? _classController.text).trim();
    if (query.isEmpty) return;
    if (_classStatsForClass == query && _classStats != null) return;
    setState(() {
      _classStatsLoading = true;
      _classStatsError = null;
    });
    try {
      final data = context.read<DataService>();
      final stats = await data.fetchClassStats(query);
      if (!mounted) return;
      setState(() {
        _classStatsForClass = query;
        _classStats = stats;
        _classStatsError = stats == null ? 'No stats returned.' : null;
      });
    } catch (e) {
      if (!mounted) return;
      setState(() {
        _classStatsError = 'Failed to load stats: $e';
      });
    } finally {
      if (mounted) {
        setState(() => _classStatsLoading = false);
      }
    }
  }

  Widget _buildClassStatsCard(BuildContext context) {
    final scheme = Theme.of(context).colorScheme;
    if (_classStatsLoading) {
      return Card(
        child: Padding(
          padding: const EdgeInsets.all(16.0),
          child: Row(
            children: const [
              SizedBox(
                height: 16,
                width: 16,
                child: CircularProgressIndicator(strokeWidth: 2),
              ),
              SizedBox(width: 12),
              Text('Loading class stats...'),
            ],
          ),
        ),
      );
    }

    if (_classStatsError != null) {
      return Card(
        child: Padding(
          padding: const EdgeInsets.all(16.0),
          child: Text(
            _classStatsError!,
            style: TextStyle(color: scheme.error),
          ),
        ),
      );
    }

    final stats = _classStats;
    if (stats == null) {
      return const SizedBox.shrink();
    }

    final totalMileage =
        (stats['total_mileage_with_class'] as num?)?.toDouble() ?? 0.0;
    final avgMileagePerEntry =
        (stats['avg_mileage_per_entry'] as num?)?.toDouble() ?? 0.0;
    final avgMileagePerLoco =
        (stats['avg_mileage_per_loco_had'] as num?)?.toDouble() ?? 0.0;
    final hadCount = stats['had_count']?.toString() ?? '0';
    final entriesWithClass = stats['entries_with_class']?.toString() ?? '0';

    final classStats = stats['class_stats'] is Map
        ? Map<String, dynamic>.from(stats['class_stats'])
        : const <String, dynamic>{};
    final totalCount = (classStats['total'] as num?)?.toInt() ??
        _sumCounts(classStats['status']) ??
        0;
    final statusList = _normalizeStatList(classStats['status'], 'status');
    final domainList = _normalizeStatList(classStats['domain'], 'domain');

    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              children: [
                Expanded(
                  child: Text(
                    stats['loco_class']?.toString() ?? 'Class stats',
                    style: Theme.of(context).textTheme.titleMedium,
                  ),
                ),
                TextButton.icon(
                  onPressed: _loadClassStats,
                  icon: const Icon(Icons.refresh),
                  label: const Text('Refresh'),
                ),
              ],
            ),
            const SizedBox(height: 12),
            Wrap(
              spacing: 16,
              runSpacing: 8,
              children: [
                _metricTile('Had', hadCount),
                _metricTile('Entries', entriesWithClass),
                _metricTile('Avg mi / loco had', avgMileagePerLoco.toStringAsFixed(2)),
                _metricTile('Avg mi / entry', avgMileagePerEntry.toStringAsFixed(2)),
                _metricTile('Total mileage', totalMileage.toStringAsFixed(2)),
              ],
            ),
            const SizedBox(height: 12),
            if (statusList.isNotEmpty)
              _statBar(
                context,
                title: 'By status',
                items: statusList,
                total: totalCount,
                colorFor: (label) => _statusColor(label, scheme),
              ),
            if (domainList.isNotEmpty) ...[
              const SizedBox(height: 10),
              _statBar(
                context,
                title: 'By domain',
                items: domainList,
                total: totalCount,
                colorFor: (label) => _domainColor(label, scheme),
              ),
            ],
          ],
        ),
      ),
    );
  }

  Widget _metricTile(String label, String value) {
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
      decoration: BoxDecoration(
        color: Colors.grey.withValues(alpha: 0.1),
        borderRadius: BorderRadius.circular(8),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(label, style: const TextStyle(fontSize: 12)),
          const SizedBox(height: 4),
          Text(
            value,
            style: const TextStyle(fontWeight: FontWeight.w700),
          ),
        ],
      ),
    );
  }

  Widget _statBar(
    BuildContext context, {
    required String title,
    required List<Map<String, dynamic>> items,
    required int total,
    required Color Function(String) colorFor,
  }) {
    if (total <= 0) {
      return const SizedBox.shrink();
    }
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text(title, style: Theme.of(context).textTheme.labelMedium),
        const SizedBox(height: 6),
        ClipRRect(
          borderRadius: BorderRadius.circular(8),
          child: Row(
            children: items.map((item) {
              final label = item['label']?.toString() ?? '';
              final count = (item['count'] as num?)?.toInt() ?? 0;
              final pct = total == 0 ? 0.0 : (count / total) * 100;
              final flex = count == 0 ? 1 : (count * 1000 / total).round();
              return Expanded(
                flex: flex,
                child: Tooltip(
                  message:
                      '$label: $count (${pct.isNaN ? 0 : pct.toStringAsFixed(1)}%)',
                  child: Container(
                    height: 16,
                    color: colorFor(label),
                  ),
                ),
              );
            }).toList(),
          ),
        ),
        const SizedBox(height: 6),
        Wrap(
          spacing: 12,
          runSpacing: 6,
          children: items.map((item) {
            final label = item['label']?.toString() ?? '';
            final count = (item['count'] as num?)?.toInt() ?? 0;
            final pct = total == 0 ? 0.0 : (count / total) * 100;
            return Row(
              mainAxisSize: MainAxisSize.min,
              children: [
                Container(
                  width: 10,
                  height: 10,
                  margin: const EdgeInsets.only(right: 6),
                  decoration: BoxDecoration(
                    color: colorFor(label),
                    borderRadius: BorderRadius.circular(2),
                  ),
                ),
                Text('$label (${pct.isNaN ? 0 : pct.toStringAsFixed(1)}%, $count)'),
              ],
            );
          }).toList(),
        ),
      ],
    );
  }

  List<Map<String, dynamic>> _normalizeStatList(dynamic list, String labelKey) {
    if (list is! List) return const [];
    return list
        .whereType<Map>()
        .map((item) => {
              'label': item[labelKey]?.toString() ?? '',
              'count': (item['count'] as num?)?.toInt() ?? 0,
            })
        .where((item) => (item['label'] ?? '').toString().isNotEmpty)
        .toList();
  }

  int? _sumCounts(dynamic list) {
    if (list is! List) return null;
    int total = 0;
    for (final item in list) {
      final count = (item is Map ? item['count'] : null) as num?;
      if (count != null) total += count.toInt();
    }
    return total;
  }

  Color _statusColor(String status, ColorScheme scheme) {
    final key = status.toLowerCase();
    if (key.contains('scrap')) return Colors.red.shade600;
    if (key.contains('active')) return scheme.primary;
    if (key.contains('overhaul')) return Colors.blueGrey;
    if (key.contains('withdrawn')) return Colors.amber.shade700;
    if (key.contains('stored')) return Colors.grey.shade600;
    return scheme.tertiary;
  }

  Color _domainColor(String domain, ColorScheme scheme) {
    final palette = [
      scheme.primary,
      scheme.secondary,
      scheme.tertiary,
      Colors.teal,
      Colors.indigo,
      Colors.orange,
      Colors.pink,
      Colors.brown,
    ];
    if (domain.isEmpty) return scheme.surfaceContainerHighest;
    final index = domain.hashCode.abs() % palette.length;
    return palette[index];
  }

  void _toggleSelection(LocoSummary loco) {
    final keyVal = '${loco.locoClass}-${loco.number}';
    if (widget.onSelect != null) {
      widget.onSelect!(loco);
    }
    setState(() {
      if (_selectedKeys.contains(keyVal)) {
        _selectedKeys.remove(keyVal);
      } else {
        _selectedKeys.add(keyVal);
      }
    });
  }

  bool _isSelected(LocoSummary loco) {
    final keyVal = '${loco.locoClass}-${loco.number}';
    return _selectedKeys.contains(keyVal);
  }

  Future<void> _openTimeline(LocoSummary loco) async {
    final label = '${loco.locoClass} ${loco.number}'.trim();
    await context.push(
      '/traction/${loco.id}/timeline',
      extra: {'label': label},
    );
    if (!mounted) return;
    await _refreshTraction();
  }

  Future<void> _openLegs(LocoSummary loco) async {
    final label = '${loco.locoClass} ${loco.number}'.trim();
    await context.push(
      '/traction/${loco.id}/legs',
      extra: {'label': label},
    );
  }

  Widget _buildFilterInput(
    BuildContext context,
    EventField field,
    bool isMobile,
  ) {
    final width = isMobile ? double.infinity : 220.0;
    if (field.enumValues != null && field.enumValues!.isNotEmpty) {
      final options = field.enumValues!
          .map((e) => e.toString())
          .toSet()
          .toList();
      final currentValue = _enumSelections[field.name];
      final safeValue = options.contains(currentValue) ? currentValue : null;
      return SizedBox(
        width: width,
        child: DropdownButtonFormField<String?>(
          value: safeValue,
          decoration: InputDecoration(
            labelText: field.display,
            border: const OutlineInputBorder(),
          ),
          items: [
            const DropdownMenuItem(value: null, child: Text('Any')),
            ...options.map(
              (value) => DropdownMenuItem(value: value, child: Text(value)),
            ),
          ],
          onChanged: (val) {
            setState(() {
              _enumSelections[field.name] = val;
            });
            _refreshTraction();
          },
        ),
      );
    }

    final controller =
        _dynamicControllers[field.name] ?? TextEditingController();
    _dynamicControllers[field.name] = controller;
    TextInputType? inputType;
    if (field.type != null) {
      final type = field.type!.toLowerCase();
      if (type.contains('int') ||
          type.contains('num') ||
          type.contains('double')) {
        inputType = const TextInputType.numberWithOptions(decimal: true);
      }
    }

    return SizedBox(
      width: width,
      child: TextField(
        controller: controller,
        keyboardType: inputType,
        decoration: InputDecoration(
          labelText: field.display,
          border: const OutlineInputBorder(),
        ),
        onSubmitted: (_) => _refreshTraction(),
      ),
    );
  }

  Widget _buildTractionSliver(
    BuildContext context,
    DataService data,
    List<LocoSummary> traction,
  ) {
    if (data.isTractionLoading && traction.isEmpty) {
      return const SliverToBoxAdapter(
        child: Padding(
          padding: EdgeInsets.symmetric(vertical: 32.0),
          child: Center(child: CircularProgressIndicator()),
        ),
      );
    }

    if (traction.isEmpty) {
      return SliverToBoxAdapter(
        child: Card(
          child: Padding(
            padding: const EdgeInsets.all(16.0),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  'No traction found',
                  style: Theme.of(context).textTheme.titleMedium?.copyWith(
                    fontWeight: FontWeight.w700,
                  ),
                ),
                const SizedBox(height: 8),
                const Text('Try relaxing the filters or sync again.'),
              ],
            ),
          ),
        ),
      );
    }

    final itemCount =
        traction.length + ((data.tractionHasMore || data.isTractionLoading) ? 1 : 0);

    return SliverList(
      delegate: SliverChildBuilderDelegate(
        (context, index) {
          if (index < traction.length) {
            final loco = traction[index];
            return TractionCard(
              loco: loco,
              selectionMode: widget.selectionMode,
              isSelected: _isSelected(loco),
              onShowInfo: () => showTractionDetails(context, loco),
              onOpenTimeline: () => _openTimeline(loco),
              onOpenLegs: () => _openLegs(loco),
              onToggleSelect:
                  widget.selectionMode ? () => _toggleSelection(loco) : null,
            );
          }

          return Padding(
            padding: const EdgeInsets.only(top: 8.0),
            child: OutlinedButton.icon(
              onPressed:
                  data.isTractionLoading ? null : () => _refreshTraction(append: true),
              icon: data.isTractionLoading
                  ? const SizedBox(
                      height: 14,
                      width: 14,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : const Icon(Icons.expand_more),
              label: Text(
                data.isTractionLoading ? 'Loading...' : 'Load more',
              ),
            ),
          );
        },
        childCount: itemCount,
      ),
    );
  }
}