import "dart:io";
import "dart:typed_data";
import "package:flutter/foundation.dart";
import "package:flutter/material.dart";
import "package:file_saver/file_saver.dart";
import "package:go_router/go_router.dart";
import "package:path_provider/path_provider.dart";
import "package:share_plus/share_plus.dart";
import "../models/trip.dart";
import "../models/brr_metadata.dart";
import "../models/brr_state.dart";
import "../services/brr_export_service.dart";
import "../services/storage_service.dart";

class TripListPage extends StatefulWidget {
  final List<Trip> trips;
  final String fileName;
  final bool fromStationSelection;
  final BRROperator operator;
  final String? routeName;

  const TripListPage({
    super.key,
    required this.trips,
    required this.fileName,
    this.fromStationSelection = false,
    this.operator = BRROperator.arriva,
    this.routeName,
  });

  static GoRoute route = GoRoute(
    path: "/trips",
    builder: (context, state) {
      final extra = state.extra as Map<String, dynamic>?;
      if (extra == null) {
        // extra is lost on hot reload — home will restore from storage
        WidgetsBinding.instance.addPostFrameCallback((_) {
          context.go("/");
        });
        return const SizedBox.shrink();
      }
      return TripListPage(
        trips: (extra["trips"] as List).cast<Trip>(),
        fileName: extra["fileName"] as String,
        fromStationSelection: extra.containsKey("station"),
        operator: extra["operator"] as BRROperator? ?? BRROperator.arriva,
        routeName: extra["routeName"] as String?,
      );
    },
  );

  @override
  State<TripListPage> createState() => _TripListPageState();
}

class _TripListPageState extends State<TripListPage> {
  late List<Trip> _trips;
  bool _isExporting = false;
  String? _expandedTripId;
  final _storageService = StorageService();

  @override
  void initState() {
    super.initState();
    _trips = List.from(widget.trips);
    if (widget.operator == BRROperator.arriva) {
      _trips.sort((a, b) => int.tryParse(a.tripNumber)?.compareTo(int.tryParse(b.tripNumber) ?? 0) ?? a.tripNumber.compareTo(b.tripNumber));
    } else {
      final firstMins = _toMins(_trips.first.scheduledTime);
      _trips.sort((a, b) => _sortableTime(a.scheduledTime, firstMins).compareTo(_sortableTime(b.scheduledTime, firstMins)));
    }
    _autoSave();
  }

  int _toMins(String time) {
    final parts = time.split(":");
    if (parts.length != 2) return 0;
    return (int.tryParse(parts[0]) ?? 0) * 60 + (int.tryParse(parts[1]) ?? 0);
  }

  // Anything earlier than the first trip's time is treated as next-day.
  int _sortableTime(String time, int thresholdMins) {
    final mins = _toMins(time);
    return mins < thresholdMins ? mins + 1440 : mins;
  }

  Future<void> _autoSave() async {
    final state = BRRState(
      trips: _trips,
      scheduleFileName: widget.fileName,
      uploadedAt: DateTime.now(),
    );
    await _storageService.saveState(state);
  }

  int get _completedCount => _trips.where((t) => t.isComplete).length;

  String get _exportFileName =>
      "BRR_${DateTime.now().toString().split(" ")[0].replaceAll("-", "_")}.xlsx";

  Future<void> _handleExport() async {
    setState(() => _isExporting = true);

    try {
      final metadata = BRRMetadata(
        route: widget.routeName ?? "Unknown",
        date: DateTime.now().toString().split(" ")[0].replaceAll("-", "_"),
        location: "Unknown",
        controller: "Unknown",
      );

      final exportService = BRRExportService(operator: widget.operator);
      final result = await exportService.exportBRR(_trips, metadata);

      if (!mounted) return;

      if (result.isSuccess) {
        await _saveFile(result.bytes!, _exportFileName);
      } else {
        if (mounted) {
          showDialog(
            context: context,
            builder: (context) => AlertDialog(
              title: const Text("Cannot Export"),
              content: Text(result.errors.join("\n")),
              actions: [
                TextButton(
                  onPressed: () => Navigator.pop(context),
                  child: const Text("OK"),
                ),
              ],
            ),
          );
        }
      }
    } finally {
      if (mounted) setState(() => _isExporting = false);
    }
  }

  Future<void> _saveFile(Uint8List bytes, String fileName) async {
    if (!kIsWeb && (Platform.isAndroid || Platform.isIOS)) {
      final tmp = await getTemporaryDirectory();
      final file = File("${tmp.path}/$fileName");
      await file.writeAsBytes(bytes);

      await Share.shareXFiles(
        [XFile(file.path)],
        subject: "BRR ${DateTime.now().toString().split(" ")[0]}",
      );
    } else {
      await FileSaver.instance.saveFile(
        name: fileName.replaceAll(".xlsx", ""),
        bytes: bytes,
        ext: "xlsx",
        mimeType: MimeType.microsoftExcel,
      );
    }
  }

  void _updateTrip(int index, Trip updatedTrip) {
    setState(() {
      _trips[index] = updatedTrip;
    });
    _autoSave();
  }

  @override
  Widget build(BuildContext context) {
    final progress = _trips.isEmpty ? 0.0 : _completedCount / _trips.length;

    return Scaffold(
      appBar: AppBar(
        leading: IconButton(
          icon: const Icon(Icons.arrow_back, size: 20),
          onPressed: () async {
            await _storageService.clearState();
            if (!mounted) return;
            if (widget.fromStationSelection) {
              context.go("/station-selection", extra: {
                "trips": widget.trips,
                "fileName": widget.fileName,
              });
            } else {
              context.go("/");
            }
          },
        ),
        title: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            const Text("TRIPS"),
            Text(
              widget.fileName,
              style: const TextStyle(
                fontSize: 11,
                color: Color(0xFF777777),
                fontWeight: FontWeight.w400,
              ),
            ),
          ],
        ),
        actions: [
          Padding(
            padding: const EdgeInsets.only(right: 12),
            child: TextButton(
              onPressed: _isExporting ? null : _handleExport,
              style: TextButton.styleFrom(
                backgroundColor: const Color(0xFF00A9CE),
                foregroundColor: Colors.black,
                padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 6),
                shape: const RoundedRectangleBorder(
                  borderRadius: BorderRadius.all(Radius.circular(3)),
                ),
                textStyle: const TextStyle(
                  fontWeight: FontWeight.w700,
                  fontSize: 12,
                  letterSpacing: 0.5,
                ),
              ),
              child: _isExporting
                  ? const SizedBox(
                      width: 14,
                      height: 14,
                      child: CircularProgressIndicator(strokeWidth: 2, color: Colors.black),
                    )
                  : const Text("EXPORT"),
            ),
          ),
        ],
      ),
      body: Column(
        children: [
          // progress bar
          Container(
            color: const Color(0xFF1A1A1A),
            padding: const EdgeInsets.fromLTRB(16, 10, 16, 12),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Row(
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  children: [
                    Text(
                      "$_completedCount / ${_trips.length}",
                      style: const TextStyle(
                        fontSize: 13,
                        fontWeight: FontWeight.w700,
                        color: Color(0xFFEEEEEE),
                        fontFamily: "monospace",
                      ),
                    ),
                    Text(
                      "${(progress * 100).toStringAsFixed(0)}% complete",
                      style: const TextStyle(
                        fontSize: 12,
                        color: Color(0xFF777777),
                      ),
                    ),
                  ],
                ),
                const SizedBox(height: 8),
                ClipRRect(
                  borderRadius: BorderRadius.circular(2),
                  child: LinearProgressIndicator(
                    value: progress,
                    minHeight: 4,
                    backgroundColor: const Color(0xFF2E2E2E),
                    valueColor: const AlwaysStoppedAnimation(Color(0xFF00A9CE)),
                  ),
                ),
              ],
            ),
          ),

          Expanded(
            child: ListView.builder(
              itemCount: _trips.length,
              padding: const EdgeInsets.symmetric(vertical: 8),
              itemBuilder: (context, index) {
                final trip = _trips[index];
                final tripId = "${trip.tripNumber}_$index";
                final isExpanded = _expandedTripId == tripId;

                // find the next trip this duty runs after this one
                final nextDutyTrip = _trips
                    .skip(index + 1)
                    .where((t) => t.dutyNumber == trip.dutyNumber)
                    .firstOrNull;

                return TripCard(
                  trip: trip,
                  nextDutyTrip: nextDutyTrip,
                  isExpanded: isExpanded,
                  onTap: () {
                    setState(() {
                      _expandedTripId = isExpanded ? null : tripId;
                    });
                  },
                  onUpdate: (updatedTrip) => _updateTrip(index, updatedTrip),
                );
              },
            ),
          ),
        ],
      ),
    );
  }
}

class TripCard extends StatefulWidget {
  final Trip trip;
  final Trip? nextDutyTrip;
  final bool isExpanded;
  final VoidCallback onTap;
  final Function(Trip) onUpdate;

  const TripCard({
    super.key,
    required this.trip,
    this.nextDutyTrip,
    required this.isExpanded,
    required this.onTap,
    required this.onUpdate,
  });

  @override
  State<TripCard> createState() => _TripCardState();
}

class _TripCardState extends State<TripCard> {
  late TextEditingController _actualTimeController;
  late TextEditingController _actualFleetController;

  @override
  void initState() {
    super.initState();
    _actualTimeController = TextEditingController(text: widget.trip.actualDepartureTime ?? "");
    _actualFleetController = TextEditingController(text: widget.trip.actualFleetNumber ?? "");
  }

  @override
  void dispose() {
    _actualTimeController.dispose();
    _actualFleetController.dispose();
    super.dispose();
  }

  void _saveChanges() {
    final updated = widget.trip.copyWith(
      actualDepartureTime: _actualTimeController.text.isEmpty ? null : _actualTimeController.text,
      actualFleetNumber: _actualFleetController.text.isEmpty ? null : _actualFleetController.text,
    );
    widget.onUpdate(updated);
  }

  void _setSameAsScheduled() {
    _actualTimeController.text = widget.trip.scheduledTime;
    _saveChanges();
  }

  void _setNow() {
    final now = DateTime.now();
    _actualTimeController.text =
        "${now.hour.toString().padLeft(2, "0")}:${now.minute.toString().padLeft(2, "0")}";
    _saveChanges();
  }

  @override
  Widget build(BuildContext context) {
    final isComplete = widget.trip.isComplete;

    return Container(
      margin: const EdgeInsets.symmetric(horizontal: 12, vertical: 3),
      decoration: BoxDecoration(
        color: const Color(0xFF1E1E1E),
        border: Border(
          left: BorderSide(
            color: isComplete ? const Color(0xFF4CAF50) : const Color(0xFF2E2E2E),
            width: 3,
          ),
        ),
      ),
      child: InkWell(
        onTap: widget.onTap,
        child: Column(
          children: [
            // collapsed row
            Padding(
              padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 12),
              child: Row(
                children: [
                  // time
                  SizedBox(
                    width: 72,
                    child: Text(
                      widget.trip.scheduledTime,
                      style: const TextStyle(
                        fontSize: 20,
                        fontWeight: FontWeight.w900,
                        fontFamily: "monospace",
                        color: Color(0xFFEEEEEE),
                        letterSpacing: -0.5,
                      ),
                    ),
                  ),

                  const SizedBox(width: 12),

                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        Container(
                          padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 3),
                          decoration: BoxDecoration(
                            color: const Color(0xFF252525),
                            border: Border.all(color: const Color(0xFF2E2E2E)),
                            borderRadius: BorderRadius.circular(3),
                          ),
                          child: Text(
                            "Trip ${widget.trip.tripNumber}",
                            style: const TextStyle(
                              fontSize: 13,
                              fontWeight: FontWeight.w600,
                              color: Color(0xFFCCCCCC),
                            ),
                          ),
                        ),
                        const SizedBox(height: 2),
                      ],
                    ),
                  ),

                  if (widget.trip.isFinishing)
                    Container(
                      margin: const EdgeInsets.only(right: 8),
                      padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
                      color: const Color(0xFF2A1A00),
                      child: const Text(
                        "FIN",
                        style: TextStyle(
                          fontSize: 10,
                          fontWeight: FontWeight.w700,
                          color: Color(0xFF00A9CE),
                          letterSpacing: 1,
                        ),
                      ),
                    ),

                  Icon(
                    widget.isExpanded
                        ? Icons.keyboard_arrow_up
                        : Icons.keyboard_arrow_down,
                    size: 18,
                    color: const Color(0xFF555555),
                  ),
                ],
              ),
            ),

            // expanded section
            if (widget.isExpanded) ...[
              Container(height: 1, color: const Color(0xFF2E2E2E)),

              Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [

                  Padding(
                    padding: const EdgeInsets.all(16.0),
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [

                        // scheduled info grid
                        Row(
                          children: [
                            _InfoCell("DUTY", widget.trip.dutyNumber),
                            const SizedBox(width: 12),
                            _InfoCell("RUNNING", widget.trip.runningNumber),
                          ],
                        ),

                        const SizedBox(height: 16),

                        // actual departure time
                        const Text(
                          "ACTUAL TIME",
                          style: TextStyle(
                            fontSize: 10,
                            fontWeight: FontWeight.w700,
                            color: Color(0xFF666666),
                            letterSpacing: 1.5,
                          ),
                        ),
                        const SizedBox(height: 6),
                        Row(
                          children: [
                            Expanded(
                              child: SizedBox(
                                height: 48,
                                child: TextField(
                                  controller: _actualTimeController,
                                  style: const TextStyle(
                                    fontFamily: "monospace",
                                    fontSize: 16,
                                    fontWeight: FontWeight.w700,
                                  ),
                                  decoration: InputDecoration(
                                    hintText: "HH:MM",
                                    suffixIcon: _actualTimeController.text.isNotEmpty
                                        ? IconButton(
                                            icon: const Icon(Icons.close, size: 16),
                                            onPressed: () {
                                              _actualTimeController.clear();
                                              _saveChanges();
                                            },
                                          )
                                        : null,
                                  ),
                                  onChanged: (_) { setState(() {}); _saveChanges(); },
                                ),
                              ),
                            ),
                            const SizedBox(width: 8),
                            SizedBox(
                              height: 48,
                              child: OutlinedButton(
                                onPressed: _setNow,
                                style: OutlinedButton.styleFrom(
                                  foregroundColor: const Color(0xFF999999),
                                  side: const BorderSide(color: Color(0xFF3A3A3A)),
                                  shape: const RoundedRectangleBorder(
                                    borderRadius: BorderRadius.all(Radius.circular(3)),
                                  ),
                                  padding: const EdgeInsets.symmetric(horizontal: 10),
                                  textStyle: const TextStyle(fontSize: 11, fontWeight: FontWeight.w600),
                                ),
                                child: const Text("NOW"),
                              ),
                            ),
                            const SizedBox(width: 8),
                            SizedBox(
                              height: 48,
                              child: OutlinedButton(
                                onPressed: _setSameAsScheduled,
                                style: OutlinedButton.styleFrom(
                                  foregroundColor: const Color(0xFF999999),
                                  side: const BorderSide(color: Color(0xFF3A3A3A)),
                                  shape: const RoundedRectangleBorder(
                                    borderRadius: BorderRadius.all(Radius.circular(3)),
                                  ),
                                  padding: const EdgeInsets.symmetric(horizontal: 10),
                                  textStyle: const TextStyle(fontSize: 11, fontWeight: FontWeight.w600),
                                ),
                                child: const Text("AS SCHED"),
                              ),
                            ),
                          ],
                        ),

                        const SizedBox(height: 14),

                        // actual fleet
                        const Text(
                          "ACTUAL FLEET",
                          style: TextStyle(
                            fontSize: 10,
                            fontWeight: FontWeight.w700,
                            color: Color(0xFF666666),
                            letterSpacing: 1.5,
                          ),
                        ),
                        const SizedBox(height: 6),
                        Row(
                          children: [
                            Expanded(
                              child: TextField(
                                controller: _actualFleetController,
                                style: const TextStyle(
                                  fontFamily: "monospace",
                                  fontSize: 16,
                                  fontWeight: FontWeight.w700,
                                ),
                                decoration: const InputDecoration(
                                  hintText: "EC###",
                                ),
                                onChanged: (_) => _saveChanges(),
                              ),
                            ),
                          ],
                        ),

                      ],
                    ),
                  ),

                  Container(height: 1, color: const Color(0xFF2E2E2E)),

                  Padding(
                    padding: const EdgeInsets.all(16.0),
                    child: const Text(
                      "SCHEDULE",
                      style: TextStyle(
                        fontSize: 10,
                        fontWeight: FontWeight.w700,
                        color: Color(0xFF666666),
                        letterSpacing: 1.5,
                      ),
                    ),
                  ),

                  _ScheduleDiagram(
                    stations: widget.trip.stationOrder,
                    stationTimes: widget.trip.stationTimes,
                    nextDutyTrip: widget.nextDutyTrip,
                    leftOffset: 16,
                  ),

                  Container(height: 1, color: const Color(0xFF2E2E2E)),

                  SizedBox(height: 16),
                ],
              ),
            ],
          ],
        ),
      ),
    );
  }
}

class _ScheduleDiagram extends StatelessWidget {
  final List<String> stations;
  final Map<String, String> stationTimes;
  final Trip? nextDutyTrip;
  final double leftOffset;

  const _ScheduleDiagram({required this.stations, required this.stationTimes, this.nextDutyTrip, this.leftOffset = 0});

  static const double rowHeight = 32;
  static const double lineW = 7;
  static const double dotSize = 15;

  @override
  Widget build(BuildContext context) {
    final lineColor = Theme.of(context).colorScheme.primary;
    final placeholderLabel = nextDutyTrip != null
        ? "BECOMES: TRIP ${nextDutyTrip!.tripNumber}"
        : "END OF DUTY";
    final placeholderTime = nextDutyTrip?.scheduledTime;
    // deduplicate stops with the same name + time anywhere in the list
    final deduped = <String>[];
    final seen = <String>{};
    for (final s in stations) {
      final key = "$s|${stationTimes[s]}";
      if (seen.contains(key)) continue;
      seen.add(key);
      deduped.add(s);
    }

    final displayStations = [...deduped, placeholderLabel];
    final displayTimes = Map<String, String>.from(stationTimes);
    if (placeholderTime != null) displayTimes[placeholderLabel] = placeholderTime;
    final totalHeight = displayStations.length * rowHeight;

    return Stack(
      children: [
        // the painted line + dots behind the labels
        SizedBox(
          height: totalHeight,
          width: double.infinity,
          child: CustomPaint(
            painter: _LineDiagramPainter(
              count: displayStations.length,
              rowHeight: rowHeight,
              lineW: lineW,
              dotSize: dotSize,
              lineColor: lineColor,
              leftOffset: leftOffset,
            ),
          ),
        ),

        // labels column on top
        Positioned.fill(child: Column(
          children: List.generate(displayStations.length, (i) {
            final station = displayStations[i];
            final time = displayTimes[station];

            return Container(
              height: rowHeight,
              color: i == displayStations.length - 1
                  ? lineColor.withValues(alpha: 0.12)
                  : i.isOdd ? Colors.white.withValues(alpha: 0.03) : null,
              child: Padding(
                padding: EdgeInsets.only(left: leftOffset + 26, right: 16),
                child: Row(
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  children: [
                    Text(
                      station,
                      style: const TextStyle(
                        fontSize: 13,
                        color: Color(0xFFDDDDDD),
                        fontWeight: FontWeight.w600,
                        letterSpacing: 0.5,
                      ),
                    ),
                    Text(
                      time ?? "--:--",
                      style: TextStyle(
                        fontSize: 13,
                        fontFamily: "monospace",
                        fontWeight: FontWeight.w700,
                        color: time != null
                            ? const Color(0xFFEEEEEE)
                            : const Color(0xFF555555),
                      ),
                    ),
                  ],
                ),
              ),
            );
          }),
        )),
      ],
    );
  }
}

class _LineDiagramPainter extends CustomPainter {
  final int count;
  final double rowHeight;
  final double lineW;
  final double dotSize;
  final Color lineColor;

  // metro_map_maker constants, scaled ~3.5x (world units → screen px, base line = 6px world)
  static const double _linePad = 3.0;
  static const double _blobPad = 4.0;
  static const double _centerSize = 4.0;
  static const double _cornerFactor = 0.3;

  final double leftOffset;

  _LineDiagramPainter({
    required this.count,
    required this.rowHeight,
    required this.lineW,
    required this.dotSize,
    required this.lineColor,
    this.leftOffset = 0,
  });

  @override
  void paint(Canvas canvas, Size size) {
    // derived — mirrors metro_map_maker getStationRingGeometry
    final strokeW = lineW / 2.0;                       // baseStrokeWidth
    final ringSize = _centerSize + strokeW;             // kStationCenterSize + strokeW
    final paddingWidth = strokeW + _blobPad;            // kStationBlobPaddingWidth + strokeW

    // cx: enough left margin for the station blob outline, plus caller offset
    final cx = leftOffset + ringSize / 2 + paddingWidth / 2 + 2;

    final firstY = rowHeight / 2;
    final lastY = (count - 1) * rowHeight + rowHeight / 2;

    // build rrects once for reuse
    final rrects = List.generate(count, (i) {
      final cy = i * rowHeight + rowHeight / 2;
      final rect = Rect.fromCenter(center: Offset(cx, cy), width: ringSize, height: ringSize);
      return RRect.fromRectAndRadius(rect, Radius.circular(ringSize * _cornerFactor));
    });

    // ── pass 1: station white padding (under everything) ─────────────
    for (final rrect in rrects) {
      canvas.drawRRect(
        rrect,
        Paint()
          ..color = Colors.white
          ..strokeWidth = paddingWidth
          ..style = PaintingStyle.stroke,
      );
    }

    // ── pass 2: line white padding ────────────────────────────────────
    canvas.drawLine(
      Offset(cx, firstY),
      Offset(cx, lastY),
      Paint()
        ..color = Colors.white
        ..strokeWidth = lineW + _linePad
        ..strokeCap = StrokeCap.round
        ..style = PaintingStyle.stroke,
    );

    // ── pass 3: colored line ──────────────────────────────────────────
    canvas.drawLine(
      Offset(cx, firstY),
      Offset(cx, lastY),
      Paint()
        ..color = lineColor
        ..strokeWidth = lineW
        ..strokeCap = StrokeCap.round
        ..style = PaintingStyle.stroke,
    );

    // ── pass 4: station white fill + colored ring (on top of line) ────
    for (final rrect in rrects) {
      final centerRRect = rrect.deflate(strokeW / 2);

      canvas.drawRRect(centerRRect, Paint()..color = Colors.white..style = PaintingStyle.fill);

      canvas.drawRRect(
        rrect,
        Paint()
          ..color = lineColor
          ..strokeWidth = strokeW
          ..style = PaintingStyle.stroke,
      );
    }
  }

  @override
  bool shouldRepaint(_LineDiagramPainter old) =>
      old.count != count || old.lineColor != lineColor || old.lineW != lineW || old.leftOffset != leftOffset;
}

class _InfoCell extends StatelessWidget {
  final String label;
  final String value;

  const _InfoCell(this.label, this.value);

  @override
  Widget build(BuildContext context) {
    return Expanded(
      child: Container(
        padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 8),
        color: const Color(0xFF252525),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(
              label,
              style: const TextStyle(
                fontSize: 9,
                fontWeight: FontWeight.w700,
                color: Color(0xFF666666),
                letterSpacing: 1.2,
              ),
            ),
            const SizedBox(height: 3),
            Text(
              value,
              style: const TextStyle(
                fontSize: 13,
                fontWeight: FontWeight.w600,
                color: Color(0xFFCCCCCC),
                fontFamily: "monospace",
              ),
              overflow: TextOverflow.ellipsis,
            ),
          ],
        ),
      ),
    );
  }
}