import 'package:flutter/material.dart';
import '../models/stop.dart';
import '../models/delivery_history.dart';
import '../services/database.dart';

class DeliveryProvider extends ChangeNotifier {
  final DatabaseService _db = DatabaseService();

  List<Stop> _stops = [];
  Set<int> _todayDeliveredIds = {};
  bool _isLoading = false;
  String? _error;
  int? _currentRouteId;
  int _navigateIndex = 0;
  bool _navigateMode = false;

  List<Stop> get stops => _stops;
  bool get isLoading => _isLoading;
  String? get error => _error;
  bool get navigateMode => _navigateMode;
  Set<int> get todayDeliveredIds => _todayDeliveredIds;
  int get navigateIndex => _navigateIndex;

  /// Stops filtered to show delivered status based on TODAY's history.
  List<Stop> get stopsWithDeliveryStatus {
    return _stops.map((s) {
      final isDeliveredToday = _todayDeliveredIds.contains(s.id);
      return s.copyWith(delivered: isDeliveredToday);
    }).toList();
  }

  int get deliveredCount => _todayDeliveredIds.length;
  int get totalStops => _stops.length;
  double get progressPercent =>
      _stops.isEmpty ? 0.0 : _todayDeliveredIds.length / _stops.length;

  /// Newspaper counts breakdown
  Map<String, int> get newspaperCounts {
    final counts = <String, int>{};
    for (final stop in _stops) {
      for (final np in stop.newspapers) {
        counts[np] = (counts[np] ?? 0) + 1;
      }
    }
    return counts;
  }

  int get totalNewspapers {
    int total = 0;
    for (final stop in _stops) {
      total += stop.newspapers.length;
    }
    return total;
  }

  /// Current stop in navigation mode
  Stop? get currentNavigateStop {
    if (!_navigateMode || _stops.isEmpty) return null;
    if (_navigateIndex >= _stops.length) return null;
    return stopsWithDeliveryStatus[_navigateIndex];
  }

  /// Get the next undelivered stop index for navigation
  int get nextUndeliveredIndex {
    final orderedStops = stopsWithDeliveryStatus;
    for (var i = 0; i < orderedStops.length; i++) {
      if (!orderedStops[i].delivered) return i;
    }
    return -1; // all delivered
  }

  // ── Load ────────────────────────────────────────────────

  Future<void> loadStops(int routeId) async {
    _currentRouteId = routeId;
    _isLoading = true;
    _error = null;
    notifyListeners();

    try {
      _stops = await _db.getStops(routeId);
      _todayDeliveredIds = await _db.getTodayDeliveredStopIds(routeId);
      _isLoading = false;
      _error = null;
    } catch (e) {
      _error = 'Failed to load stops: $e';
      _isLoading = false;
    }
    notifyListeners();
  }

  // ── Toggle Delivery ─────────────────────────────────────

  Future<void> toggleDelivered(int stopId) async {
    if (_currentRouteId == null) return;

    final isDelivered = _todayDeliveredIds.contains(stopId);
    if (isDelivered) {
      await _db.removeDeliveryRecord(_currentRouteId!, stopId);
      _todayDeliveredIds.remove(stopId);
    } else {
      await _db.recordDelivery(_currentRouteId!, stopId);
      _todayDeliveredIds.add(stopId);
    }
    notifyListeners();
  }

  // ── Reset Today ─────────────────────────────────────────

  Future<void> resetToday() async {
    if (_currentRouteId == null) return;
    await _db.resetToday(_currentRouteId!);
    _todayDeliveredIds.clear();
    notifyListeners();
  }

  // ── Navigation Mode ─────────────────────────────────────

  void startNavigation() {
    _navigateMode = true;
    _navigateIndex = nextUndeliveredIndex >= 0 ? nextUndeliveredIndex : 0;
    notifyListeners();
  }

  void stopNavigation() {
    _navigateMode = false;
    notifyListeners();
  }

  void nextStop() {
    if (_navigateIndex < _stops.length - 1) {
      _navigateIndex++;
      notifyListeners();
    }
  }

  void previousStop() {
    if (_navigateIndex > 0) {
      _navigateIndex--;
      notifyListeners();
    }
  }

  void goToStop(int index) {
    if (index >= 0 && index < _stops.length) {
      _navigateIndex = index;
      notifyListeners();
    }
  }

  // ── Statistics ──────────────────────────────────────────

  Future<List<DailyStats>> getStats({int days = 30}) async {
    if (_currentRouteId == null) return [];
    return _db.getDeliveryStats(_currentRouteId!, days: days);
  }

  Future<int> get totalDeliveries async {
    if (_currentRouteId == null) return 0;
    return _db.getTotalDeliveries(_currentRouteId!);
  }

  Future<int> get weeklyDeliveries async {
    if (_currentRouteId == null) return 0;
    return _db.getWeeklyDeliveryCount(_currentRouteId!);
  }

  // ── Notes ───────────────────────────────────────────────

  Future<void> saveNotes(int stopId, String notes) async {
    await _db.updateStopNotes(stopId, notes);
    final idx = _stops.indexWhere((s) => s.id == stopId);
    if (idx >= 0) {
      _stops[idx] = _stops[idx].copyWith(notes: notes);
      notifyListeners();
    }
  }

  // ── Delete Stop ─────────────────────────────────────────

  Future<void> deleteStop(int stopId) async {
    await _db.deleteStop(stopId);
    _stops.removeWhere((s) => s.id == stopId);
    _todayDeliveredIds.remove(stopId);
    notifyListeners();
  }

  // ── Reorder ─────────────────────────────────────────────

  Future<void> reorderStops(List<Stop> newOrder) async {
    await _db.reorderStops(newOrder);
    _stops = newOrder;
    notifyListeners();
  }

  // ── Update Coordinates ──────────────────────────────────

  Future<void> updateCoords(int stopId, double lat, double lng) async {
    await _db.updateStopCoords(stopId, lat, lng);
    final idx = _stops.indexWhere((s) => s.id == stopId);
    if (idx >= 0) {
      _stops[idx] = _stops[idx].copyWith(lat: lat, lng: lng);
      notifyListeners();
    }
  }
}