import "dart:async";
import "dart:math";

import "package:bus_running_record/models/channels/operations_channel.dart";
import "package:bus_running_record/models/operations/stop.dart";
import "package:bus_running_record/widgets/trip_diagram.dart";
import "package:flutter/foundation.dart";
import "package:go_router/go_router.dart";
import "package:shadcn_flutter/shadcn_flutter.dart";


class OperationsChannelView extends StatefulWidget {
  const OperationsChannelView({required this.channel, super.key});

  final OperationsChannel channel;

  @override
  State<OperationsChannelView> createState() => _OperationsChannelViewState();
}

class _OperationsChannelViewState extends State<OperationsChannelView> {

  bool _loadingMeta = true;
  bool _loadingDetail = false;

  String? _scheduleId;
  List<String> _duties = const [];
  List<String> _busWorkNumbers = const [];
  List<({String tripNumber, String dutyNumber})> _tripMeta = const [];
  List<String> _stopNames = const [];
  Map<String, ({String alias, String source})> _aliases = const {};

  String filterBy = "By Duty";
  Map<String, Object?> filterValue = {};

  List<OperationsTripSnapshot>? _dutyTrips;
  List<OperationsTripSnapshot>? _busTrips;
  OperationsTripSnapshot? _tripSnapshot;
  List<({OperationsTrip trip, String? time})>? _stopSchedule;
  bool _stopHasMore = false;
  bool _stopLoadingMore = false;
  int _stopOffset = 0;
  static const int _stopPageSize = 20;
  List<GlobalKey> _stopRowKeys = [];

  final ScrollController _stopScrollController = ScrollController();
  final GlobalKey _stopScrollViewKey = GlobalKey();


  @override
  void initState() {
    super.initState();
    _stopScrollController.addListener(_onStopScroll);
    unawaited(_loadMeta());
  }

  @override
  void dispose() {
    _stopScrollController.dispose();
    super.dispose();
  }

  void _onStopScroll() {
    if (!_stopHasMore || _stopLoadingMore || _loadingDetail) return;
    final pos = _stopScrollController.position;
    if (pos.pixels >= pos.maxScrollExtent - 100) {
      unawaited(_loadMoreStop());
    }
  }

  Future<dynamic> _invoke(String functionName, Map<String, dynamic> body) async {
    final client = widget.channel.client;
    client.functions.setAuth(
      client.auth.currentSession?.accessToken ?? "",
    );
    return client.functions.invoke(
      functionName,
      body: body,
      headers: {
        "Authorization": "Bearer ${client.auth.currentSession?.accessToken ?? ""}",
      },
    );
  }

  Future<void> _loadMeta() async {
    setState(() {
      _loadingMeta = true;
    });

    try {
      final response = await _invoke("operations-schedule-meta", {
        "channel_id": widget.channel.id,
      });

      final data = response.data as Map?;
      if (data == null) throw StateError("Empty response from meta function.");

      if (data["has_schedule"] != true) {
        if (!mounted) return;
        setState(() {
          _scheduleId = null;
          _loadingMeta = false;
        });
        return;
      }

      final scheduleId = (data["schedule_id"] ?? "").toString();
      final duties = List<String>.from(data["duties"] as List? ?? []);
      final busWorkNumbers = List<String>.from(data["bus_work_numbers"] as List? ?? []);

      final tripMetaRaw = data["trips"] as List? ?? [];
      final tripMeta = tripMetaRaw.map((t) {
        final m = t as Map;
        return (
          tripNumber: (m["trip_number"] ?? "").toString(),
          dutyNumber: (m["duty_number"] ?? "").toString(),
        );
      }).toList();

      final stopNames = List<String>.from(data["stop_names"] as List? ?? []);

      final aliasesRaw = data["aliases"] as List? ?? [];
      final aliases = <String, ({String alias, String source})>{};
      for (final row in aliasesRaw) {
        final m = row as Map;
        final raw = (m["raw_stop_name"] ?? "").toString().trim();
        final alias = (m["alias_stop_name"] ?? "").toString().trim();
        final source = (m["source"] ?? "user").toString();
        if (raw.isEmpty || alias.isEmpty) continue;
        aliases[Stop.normalizeName(raw)] = (alias: alias, source: source);
      }

      final firstDuty = duties.isNotEmpty ? duties.first : null;

      if (!mounted) return;
      setState(() {
        _scheduleId = scheduleId;
        _duties = duties;
        _busWorkNumbers = busWorkNumbers;
        _tripMeta = tripMeta;
        _stopNames = stopNames;
        _aliases = aliases;
        _loadingMeta = false;

        if (firstDuty != null) {
          filterBy = "By Duty";
          filterValue["By Duty"] = firstDuty;
        }
      });

      if (firstDuty != null) {
        unawaited(_loadDutyDetail(firstDuty));
      }
    } catch (error, stackTrace) {
      debugPrint("[OperationsChannelView] loadMeta failed: $error");
      debugPrintStack(stackTrace: stackTrace);
      if (!mounted) return;
      setState(() => _loadingMeta = false);
    }
  }

  Future<void> _loadDutyDetail(String dutyNumber) async {
    final scheduleId = _scheduleId;
    if (scheduleId == null) return;

    setState(() {
      _loadingDetail = true;
      _dutyTrips = null;
    });

    try {
      final response = await _invoke("operations-duty-detail", {
        "channel_id": widget.channel.id,
        "schedule_id": scheduleId,
        "duty_number": dutyNumber,
      });

      final data = response.data as Map?;
      final tripsRaw = data?["trips"] as List? ?? [];

      final snapshots = <OperationsTripSnapshot>[];
      for (final tripData in tripsRaw) {
        final m = tripData as Map;
        final trip = OperationsTrip(
          id: (m["id"] ?? "").toString(),
          scheduleId: scheduleId,
          tripNumber: (m["trip_number"] ?? "").toString(),
          dutyNumber: (m["duty_number"] ?? "").toString(),
          busWorkNumber: (m["bus_work_number"] ?? "").toString(),
          direction: (m["direction"] ?? "").toString(),
          sortOrder: (m["sort_order"] as num?)?.toInt() ?? 0,
        );

        final stopsRaw = m["stops"] as List? ?? [];
        final stops = stopsRaw.map((s) {
          final sm = s as Map;
          final name = (sm["stop_name"] ?? "").toString().trim();
          final aliasEntry = _aliases[Stop.normalizeName(name)];
          return OperationsScheduledStop(
            id: (sm["id"] ?? "").toString(),
            tripId: trip.id,
            sequence: (sm["stop_sequence"] as num?)?.toInt() ?? 0,
            name: name,
            alias: aliasEntry?.alias,
            aliasSource: aliasEntry?.source,
            scheduledTime: (sm["scheduled_time"] ?? "").toString().trim().isEmpty
                ? null
                : sm["scheduled_time"].toString(),
          );
        }).toList()
          ..sort((a, b) => a.sequence.compareTo(b.sequence));

        snapshots.add(OperationsTripSnapshot(
          trip: trip,
          stops: stops.map((s) => OperationsStop(scheduledStop: s)).toList(),
          scheduledStops: stops,
        ));
      }

      snapshots.sort((a, b) {
        final aTime = a.scheduledStops.firstOrNull?.scheduledTime ?? "";
        final bTime = b.scheduledStops.firstOrNull?.scheduledTime ?? "";
        return aTime.compareTo(bTime);
      });

      if (!mounted) return;
      setState(() {
        _dutyTrips = snapshots;
        _loadingDetail = false;
      });
    } catch (error, stackTrace) {
      debugPrint("[OperationsChannelView] loadDutyDetail failed: $error");
      debugPrintStack(stackTrace: stackTrace);
      if (!mounted) return;
      setState(() => _loadingDetail = false);
    }
  }

  Future<void> _loadBusDetail(String busWorkNumber) async {
    final scheduleId = _scheduleId;
    if (scheduleId == null) return;

    setState(() {
      _loadingDetail = true;
      _busTrips = null;
    });

    try {
      final response = await _invoke("operations-bus-detail", {
        "channel_id": widget.channel.id,
        "schedule_id": scheduleId,
        "bus_work_number": busWorkNumber,
      });

      final data = response.data as Map?;
      final tripsRaw = data?["trips"] as List? ?? [];

      final snapshots = <OperationsTripSnapshot>[];
      for (final tripData in tripsRaw) {
        final m = tripData as Map;
        final trip = OperationsTrip(
          id: (m["id"] ?? "").toString(),
          scheduleId: scheduleId,
          tripNumber: (m["trip_number"] ?? "").toString(),
          dutyNumber: (m["duty_number"] ?? "").toString(),
          busWorkNumber: (m["bus_work_number"] ?? "").toString(),
          direction: (m["direction"] ?? "").toString(),
          sortOrder: (m["sort_order"] as num?)?.toInt() ?? 0,
        );

        final stopsRaw = m["stops"] as List? ?? [];
        final stops = stopsRaw.map((s) {
          final sm = s as Map;
          final name = (sm["stop_name"] ?? "").toString().trim();
          final aliasEntry = _aliases[Stop.normalizeName(name)];
          return OperationsScheduledStop(
            id: (sm["id"] ?? "").toString(),
            tripId: trip.id,
            sequence: (sm["stop_sequence"] as num?)?.toInt() ?? 0,
            name: name,
            alias: aliasEntry?.alias,
            aliasSource: aliasEntry?.source,
            scheduledTime: (sm["scheduled_time"] ?? "").toString().trim().isEmpty
                ? null
                : sm["scheduled_time"].toString(),
          );
        }).toList()
          ..sort((a, b) => a.sequence.compareTo(b.sequence));

        snapshots.add(OperationsTripSnapshot(
          trip: trip,
          stops: stops.map((s) => OperationsStop(scheduledStop: s)).toList(),
          scheduledStops: stops,
        ));
      }

      snapshots.sort((a, b) {
        final aTime = a.scheduledStops.firstOrNull?.scheduledTime ?? "";
        final bTime = b.scheduledStops.firstOrNull?.scheduledTime ?? "";
        return aTime.compareTo(bTime);
      });

      if (!mounted) return;
      setState(() {
        _busTrips = snapshots;
        _loadingDetail = false;
      });
    } catch (error, stackTrace) {
      debugPrint("[OperationsChannelView] loadBusDetail failed: $error");
      debugPrintStack(stackTrace: stackTrace);
      if (!mounted) return;
      setState(() => _loadingDetail = false);
    }
  }

  Future<void> _loadTripDetail(String tripNumber) async {
    final scheduleId = _scheduleId;
    if (scheduleId == null) return;

    setState(() {
      _loadingDetail = true;
      _tripSnapshot = null;
    });

    try {
      final response = await _invoke("operations-trip-detail", {
        "channel_id": widget.channel.id,
        "schedule_id": scheduleId,
        "trip_number": tripNumber,
      });

      final data = response.data as Map?;
      final tripData = data?["trip"] as Map?;
      if (tripData == null) {
        if (!mounted) return;
        setState(() => _loadingDetail = false);
        return;
      }

      final trip = OperationsTrip(
        id: (tripData["id"] ?? "").toString(),
        scheduleId: scheduleId,
        tripNumber: (tripData["trip_number"] ?? "").toString(),
        dutyNumber: (tripData["duty_number"] ?? "").toString(),
        busWorkNumber: (tripData["bus_work_number"] ?? "").toString(),
        direction: (tripData["direction"] ?? "").toString(),
        sortOrder: (tripData["sort_order"] as num?)?.toInt() ?? 0,
      );

      final stopsRaw = data?["stops"] as List? ?? [];
      final stops = stopsRaw.map((s) {
        final sm = s as Map;
        final name = (sm["stop_name"] ?? "").toString().trim();
        final aliasEntry = _aliases[Stop.normalizeName(name)];
        return OperationsScheduledStop(
          id: (sm["id"] ?? "").toString(),
          tripId: trip.id,
          sequence: (sm["stop_sequence"] as num?)?.toInt() ?? 0,
          name: name,
          alias: aliasEntry?.alias,
          aliasSource: aliasEntry?.source,
          scheduledTime: (sm["scheduled_time"] ?? "").toString().trim().isEmpty
              ? null
              : sm["scheduled_time"].toString(),
        );
      }).toList();

      if (!mounted) return;
      setState(() {
        _tripSnapshot = OperationsTripSnapshot(
          trip: trip,
          stops: stops.map((s) => OperationsStop(scheduledStop: s)).toList(),
          scheduledStops: stops,
        );
        _loadingDetail = false;
      });
    } catch (error, stackTrace) {
      debugPrint("[OperationsChannelView] loadTripDetail failed: $error");
      debugPrintStack(stackTrace: stackTrace);
      if (!mounted) return;
      setState(() => _loadingDetail = false);
    }
  }

  Future<void> _loadStopDetail(String stopName) async {
    final scheduleId = _scheduleId;
    if (scheduleId == null) return;

    setState(() {
      _loadingDetail = true;
      _stopSchedule = null;
      _stopOffset = 0;
      _stopHasMore = false;
    });

    try {
      final response = await _invoke("operations-stop-detail", {
        "channel_id": widget.channel.id,
        "schedule_id": scheduleId,
        "stop_name": stopName,
        "offset": 0,
        "limit": _stopPageSize,
      });

      final data = response.data as Map?;
      final page = _parseStopSchedule(scheduleId, data?["schedule"] as List? ?? []);
      final hasMore = data?["has_more"] == true;

      if (!mounted) return;
      setState(() {
        _stopSchedule = page;
        _stopOffset = page.length;
        _stopHasMore = hasMore;
        _stopRowKeys = List.generate(page.length, (_) => GlobalKey());
        _loadingDetail = false;
      });

      WidgetsBinding.instance.addPostFrameCallback((_) => _scrollToClosestTime(page));
    } catch (error, stackTrace) {
      debugPrint("[OperationsChannelView] loadStopDetail failed: $error");
      debugPrintStack(stackTrace: stackTrace);
      if (!mounted) return;
      setState(() => _loadingDetail = false);
    }
  }

  Future<void> _loadMoreStop() async {
    final scheduleId = _scheduleId;
    if (scheduleId == null || !_stopHasMore || _stopLoadingMore) return;
    final stopName = (filterValue["By Stop"] ?? "").toString().trim();
    if (stopName.isEmpty) return;

    setState(() => _stopLoadingMore = true);

    try {
      final response = await _invoke("operations-stop-detail", {
        "channel_id": widget.channel.id,
        "schedule_id": scheduleId,
        "stop_name": stopName,
        "offset": _stopOffset,
        "limit": _stopPageSize,
      });

      final data = response.data as Map?;
      final page = _parseStopSchedule(scheduleId, data?["schedule"] as List? ?? []);
      final hasMore = data?["has_more"] == true;

      if (!mounted) return;
      setState(() {
        _stopSchedule = [...?_stopSchedule, ...page];
        _stopOffset += page.length;
        _stopHasMore = hasMore;
        _stopLoadingMore = false;
      });
    } catch (error, stackTrace) {
      debugPrint("[OperationsChannelView] loadMoreStop failed: $error");
      debugPrintStack(stackTrace: stackTrace);
      if (!mounted) return;
      setState(() => _stopLoadingMore = false);
    }
  }

  void _scrollToClosestTime(List<({OperationsTrip trip, String? time})> schedule) {
    if (!_stopScrollController.hasClients) return;
    if (schedule.isEmpty) return;

    final now = DateTime.now();
    final nowMins = now.hour * 60 + now.minute;

    int bestIndex = 0;
    int bestDiff = 9999;

    for (var i = 0; i < schedule.length; i++) {
      final time = schedule[i].time;
      if (time == null) continue;
      final parts = time.split(":");
      if (parts.length < 2) continue;
      final h = int.tryParse(parts[0]);
      final m = int.tryParse(parts[1]);
      if (h == null || m == null) continue;
      final diff = ((h * 60 + m) - nowMins).abs();
      if (diff < bestDiff) {
        bestDiff = diff;
        bestIndex = i;
      }
    }

    if (bestIndex >= _stopRowKeys.length) return;
    final rowCtx = _stopRowKeys[bestIndex].currentContext;
    if (rowCtx == null) return;

    final scrollCtx = _stopScrollViewKey.currentContext;
    if (scrollCtx == null) return;

    final rowBox = rowCtx.findRenderObject() as RenderBox?;
    final scrollBox = scrollCtx.findRenderObject() as RenderBox?;
    if (rowBox == null || scrollBox == null) return;

    final rowOffset = rowBox.localToGlobal(Offset.zero, ancestor: scrollBox);
    final target = (_stopScrollController.offset + rowOffset.dy).clamp(
      _stopScrollController.position.minScrollExtent,
      _stopScrollController.position.maxScrollExtent,
    );

    _stopScrollController.animateTo(
      target,
      duration: const Duration(milliseconds: 350),
      curve: Curves.easeOut,
    );
  }

  List<({OperationsTrip trip, String? time})> _parseStopSchedule(
    String scheduleId,
    List scheduleRaw,
  ) {
    return scheduleRaw.map((row) {
      final m = row as Map;
      final tripData = m["trip"] as Map;
      final trip = OperationsTrip(
        id: (tripData["id"] ?? "").toString(),
        scheduleId: scheduleId,
        tripNumber: (tripData["trip_number"] ?? "").toString(),
        dutyNumber: (tripData["duty_number"] ?? "").toString(),
        busWorkNumber: (tripData["bus_work_number"] ?? "").toString(),
        direction: (tripData["direction"] ?? "").toString(),
        sortOrder: 0,
      );
      final time = (m["scheduled_time"] ?? "").toString().trim();
      return (trip: trip, time: time.isEmpty ? null : time);
    }).toList();
  }

  String? _aliasForStop(String rawName) =>
      _aliases[Stop.normalizeName(rawName)]?.alias;

  Widget _stopLabel(String rawName) {
    final alias = _aliasForStop(rawName);
    if (alias == null || alias.isEmpty) return Text(rawName);
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text(alias).semiBold,
        if (alias != rawName)
          Text(
            rawName,
            style: const TextStyle(fontSize: 11, height: 1),
          ).xSmall.muted.semiBold,
      ],
    );
  }

  List<TripDiagramEntry> _diagramEntries(List<OperationsScheduledStop> stops) {
    return stops.map((stop) => TripDiagramEntry(
      label: stop.displayName,
      labelIcon: stop.aliasSource == "ai" ? LucideIcons.sparkles : null,
      subtitle: stop.displayName == stop.name ? null : stop.name,
      time: stop.scheduledTime,
    )).toList(growable: false);
  }

  @override
  Widget build(BuildContext context) {
    double bottomPadding = MediaQuery.of(context).padding.bottom;
    bool isMobile = defaultTargetPlatform == TargetPlatform.iOS ||
        defaultTargetPlatform == TargetPlatform.android;

    if (_loadingMeta) {
      return const Center(child: CircularProgressIndicator());
    }

    if (_scheduleId == null) {
      return Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Text("No schedule uploaded yet.").h4,
            Gap(8),
            Button.secondary(
              onPressed: () => context.go(
                "/channel/${widget.channel.organizationId}/${widget.channel.id}/upload",
              ),
              child: const Text("Upload Schedule"),
            ),
          ],
        ),
      );
    }

    return Column(
      children: [

        Expanded(
          child: Builder(
            builder: (context) {

              if (_loadingDetail) {
                return const Center(child: CircularProgressIndicator());
              }

              // By Stop
              if (filterBy == "By Stop") {
                final selectedStop = (filterValue["By Stop"] ?? "").toString().trim();
                if (selectedStop.isEmpty) {
                  return Center(child: Text("Select a stop to preview its schedule.").small.muted);
                }

                final schedules = _stopSchedule ?? const [];
                return Column(
                  children: [
                    Gap(8),
                    Divider(),
                    Padding(
                      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
                      child: Row(
                        children: [
                          Icon(LucideIcons.pin),
                          Gap(8),
                          _stopLabel(selectedStop),
                        ],
                      ),
                    ),
                    Divider(),
                    Gap(2),
                    Divider(),
                    Expanded(
                      child: SingleChildScrollView(
                        key: _stopScrollViewKey,
                        controller: _stopScrollController,
                        child: Column(
                          crossAxisAlignment: CrossAxisAlignment.start,
                          children: [
                            if (schedules.isEmpty)
                              Padding(
                                padding: const EdgeInsets.all(16),
                                child: Text("No scheduled times found for this stop.").small.muted,
                              )
                            else
                              ...schedules.indexed.map(
                                (entry) {
                                  final (i, row) = entry;
                                  final rowKey = i < _stopRowKeys.length ? _stopRowKeys[i] : null;
                                  return Container(
                                  key: rowKey,
                                  padding: const EdgeInsets.symmetric(vertical: 10),
                                  decoration: BoxDecoration(
                                    border: Border(
                                      bottom: BorderSide(
                                        color: Colors.white.withValues(alpha: 0.07),
                                      ),
                                    ),
                                  ),
                                  child: Row(
                                    children: [
                                      Gap(16),
                                      Expanded(
                                        child: Column(
                                          crossAxisAlignment: CrossAxisAlignment.start,
                                          children: [
                                            Row(
                                              children: [
                                                Text("${row.trip.dutyNumber} • ").extraBold,
                                                Text(
                                                  "Trip ${row.trip.tripNumber} • Bus ${row.trip.busWorkNumber}",
                                                  style: const TextStyle(
                                                    fontSize: 12,
                                                    fontWeight: FontWeight.w600,
                                                  ),
                                                ).muted,
                                              ],
                                            ),
                                            Row(
                                              children: [
                                                Text(row.trip.direction).muted.textSmall,
                                                if (row.trip.direction.toLowerCase().contains("out")) ...[
                                                  Gap(4),
                                                  Icon(LucideIcons.arrowUpRight).iconSmall,
                                                ] else if (row.trip.direction.toLowerCase().contains("in")) ...[
                                                  Gap(4),
                                                  Icon(LucideIcons.arrowDownLeft).iconSmall,
                                                ],
                                              ],
                                            ),
                                          ],
                                        ),
                                      ),
                                      Text(row.time ?? "--:--").extraBold.mono,
                                      Gap(2),
                                      Icon(LucideIcons.chevronRight),
                                      Gap(2),
                                    ],
                                  ),
                                );
                                },
                              ),

                            if (_stopLoadingMore)
                              const Padding(
                                padding: EdgeInsets.all(16),
                                child: Center(child: CircularProgressIndicator()),
                              ),
                          ],
                        ),
                      ),
                    ),
                  ],
                );
              }

              // By Bus
              if (filterBy == "By Bus") {
                final selectedBus = (filterValue["By Bus"] ?? "").toString();
                if (selectedBus.isEmpty) {
                  return Center(child: Text("Select a bus to preview.").small.muted);
                }

                final snapshots = _busTrips ?? const [];
                if (snapshots.isEmpty) {
                  return Center(child: Text("No trips found for this bus.").small.muted);
                }

                return Column(
                  children: [
                    Gap(8),
                    Divider(),
                    Container(
                      height: 50,
                      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
                      child: Row(
                        children: [
                          Icon(LucideIcons.busFront),
                          Gap(10),
                          Text("Bus $selectedBus".toUpperCase()).extraBold.textSmall,
                        ],
                      ),
                    ),
                    Divider(),
                    Gap(2),
                    Divider(),
                    Expanded(
                      child: SingleChildScrollView(
                        child: Column(
                          crossAxisAlignment: CrossAxisAlignment.start,
                          children: [
                            for (var i = 0; i < snapshots.length; i++) ...[
                              if (i != 0) ...[
                                Divider(),
                                Gap(2),
                                Divider(),
                              ],
                              Padding(
                                padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
                                child: Row(
                                  children: [
                                    Icon(LucideIcons.bus),
                                    Gap(8),
                                    Text(
                                      "Trip ${snapshots[i].trip.tripNumber} • Duty ${snapshots[i].trip.dutyNumber}",
                                    ).semiBold.textSmall,
                                  ],
                                ),
                              ),
                              Divider(),
                              TripDiagram(
                                lineColor: Colors.red,
                                entries: _diagramEntries(snapshots[i].scheduledStops),
                                leftOffset: 12,
                                rowHeight: 48,
                              ),
                            ],
                          ],
                        ),
                      ),
                    ),
                  ],
                );
              }

              // By Duty
              if (filterBy == "By Duty") {
                final selectedDuty = (filterValue["By Duty"] ?? "").toString();
                if (selectedDuty.isEmpty) {
                  return Center(child: Text("Select a duty to preview.").small.muted);
                }

                final snapshots = _dutyTrips ?? const [];
                if (snapshots.isEmpty) {
                  return Center(child: Text("No trips found for this duty.").small.muted);
                }

                return Column(
                  children: [
                    Gap(8),
                    Divider(),
                    Container(
                      height: 50,
                      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
                      child: Row(
                        children: [
                          Icon(LucideIcons.busFront),
                          Gap(10),
                          Text("Duty $selectedDuty".toUpperCase()).extraBold.textSmall,
                        ],
                      ),
                    ),
                    Divider(),
                    Gap(2),
                    Divider(),
                    Expanded(
                      child: SingleChildScrollView(
                        child: Column(
                          crossAxisAlignment: CrossAxisAlignment.start,
                          children: [
                            for (var i = 0; i < snapshots.length; i++) ...[

                              if (i != 0) ...[
                                Divider(),
                                Gap(2),
                                Divider(),
                              ],

                              Padding(
                                padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
                                child: Row(
                                  children: [
                                    Icon(LucideIcons.bus),
                                    Gap(8),
                                    Text(
                                      "Trip ${snapshots[i].trip.tripNumber} • Duty ${snapshots[i].trip.dutyNumber}",
                                    ).semiBold.textSmall,
                                  ],
                                ),
                              ),
                              Divider(),
                              TripDiagram(
                                lineColor: Colors.red,
                                entries: _diagramEntries(snapshots[i].scheduledStops),
                                leftOffset: 12,
                                rowHeight: 48,
                              ),
                            ],
                          ],
                        ),
                      ),
                    ),
                  ],
                );
              }

              // By Trip
              if (filterBy == "By Trip") {
                final selectedTripNumber = (filterValue["By Trip"] ?? "").toString();
                if (selectedTripNumber.isEmpty) {
                  return Center(child: Text("Select a trip to preview.").small.muted);
                }

                final snapshot = _tripSnapshot;
                if (snapshot == null) {
                  return Center(child: Text("No data for this trip.").small.muted);
                }

                return SingleChildScrollView(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Gap(8),
                      Divider(),
                      Padding(
                        padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
                        child: Row(
                          children: [
                            Icon(LucideIcons.bus),
                            Gap(8),
                            Text(
                              "Trip ${snapshot.trip.tripNumber} • Duty ${snapshot.trip.dutyNumber}",
                            ).semiBold.textSmall,
                          ],
                        ),
                      ),
                      Divider(),
                      TripDiagram(
                        lineColor: Colors.red,
                        entries: _diagramEntries(snapshot.scheduledStops),
                        leftOffset: 12,
                        rowHeight: 48,
                      ),
                    ],
                  ),
                );
              }

              return Center(
                child: Text("Select a filter to preview the schedule.").small.muted,
              );
            },
          ),
        ),

        Divider(),

        Padding(
          padding: const EdgeInsets.all(16),
          child: Column(
            children: [

              SizedBox(
                width: double.infinity,
                height: 50,
                child: Select<String>(
                  itemBuilder: (context, item) => Text("Filter by: $item"),
                  popupConstraints: BoxConstraints(
                    maxHeight: 300,
                    maxWidth: !isMobile ? 200 : double.infinity,
                  ),
                  onChanged: (value) {
                    setState(() {
                      filterBy = value ?? filterBy;
                    });
                  },
                  value: filterBy,
                  popup: SelectPopup(
                    items: SelectItemList(
                      children: [
                        SelectItemButton(value: "By Duty", child: Text("By Duty")),
                        SelectItemButton(value: "By Bus", child: Text("By Bus")),
                        SelectItemButton(value: "By Trip", child: Text("By Trip")),
                        SelectItemButton(value: "By Stop", child: Text("By Stop")),
                      ],
                    ),
                  ),
                ),
              ),

              Gap(16),

              SizedBox(
                width: double.infinity,
                height: 50,
                child: Select<Object>(
                  itemBuilder: (context, item) {
                    if (filterBy == "By Duty") return Text("Duty $item");

                    if (filterBy == "By Bus") return Text("Bus $item");

                    if (filterBy == "By Trip") {
                      final tripNumber = item.toString();
                      final match = _tripMeta.where((t) => t.tripNumber == tripNumber).firstOrNull;
                      if (match == null) return Text("Trip $tripNumber");
                      return Text("Trip ${match.tripNumber} • Duty ${match.dutyNumber}");
                    }

                    if (filterBy == "By Stop") return _stopLabel(item.toString());

                    return Text("Undefined");
                  },
                  popupConstraints: BoxConstraints(
                    maxHeight: 300,
                    maxWidth: !isMobile ? 200 : double.infinity,
                  ),
                  onChanged: (value) {
                    if (value == null) return;
                    setState(() {
                      filterValue[filterBy] = value;
                      _dutyTrips = null;
                      _busTrips = null;
                      _tripSnapshot = null;
                      _stopSchedule = null;
                    });
                    if (filterBy == "By Duty") {
                      unawaited(_loadDutyDetail(value.toString()));
                    } else if (filterBy == "By Bus") {
                      unawaited(_loadBusDetail(value.toString()));
                    } else if (filterBy == "By Trip") {
                      unawaited(_loadTripDetail(value.toString()));
                    } else if (filterBy == "By Stop") {
                      unawaited(_loadStopDetail(value.toString()));
                    }
                  },
                  value: filterValue[filterBy],
                  popup: SelectPopup.builder(
                    searchPlaceholder: Text("Search ${filterBy.toLowerCase()}"),
                    builder: (context, searchQuery) {
                      List<SelectItemButton> items = [];

                      if (filterBy == "By Duty") {
                        items = _duties.map((d) => SelectItemButton(
                          value: d,
                          child: Text(d),
                        )).toList();
                      } else if (filterBy == "By Bus") {
                        items = _busWorkNumbers.map((b) => SelectItemButton(
                          value: b,
                          child: Text(b),
                        )).toList();
                      } else if (filterBy == "By Trip") {
                        final trips = List.from(_tripMeta);
                        trips.sort((a, b) {
                          final aNum = int.tryParse(a.tripNumber);
                          final bNum = int.tryParse(b.tripNumber);
                          if (aNum != null && bNum != null) return aNum.compareTo(bNum);
                          return a.tripNumber.compareTo(b.tripNumber);
                        });
                        items = trips.map((t) => SelectItemButton(
                          value: t.tripNumber,
                          child: Text("Trip ${t.tripNumber}"),
                        )).toList();
                      } else if (filterBy == "By Stop") {
                        items = _stopNames.map((s) => SelectItemButton(
                          value: s,
                          child: _stopLabel(s),
                        )).toList();
                      }

                      return SelectItemList(children: items);
                    },
                  ),
                ),
              ),

            ],
          ),
        ),

        Gap(max(bottomPadding, 16)),

      ],
    );
  }
}