import 'dart:math' as math;
import 'package:intaleq_maps/intaleq_maps.dart';

enum TacticalVehicleProfile {
  convoy,      // Heavy military supply convoy (~45 km/h avg)
  offroad4x4,  // Tactical 4x4 off-road vehicle (~75 km/h highway, capable on desert tracks)
  armored,     // Heavy armored tanks/APCs (~35 km/h avg)
  rapidResponse, // Rapid intervention / light vehicle (~90 km/h)
}

class RoadNode {
  final String id;
  final String name;
  final double lat;
  final double lng;
  final int elevationM;

  const RoadNode({
    required this.id,
    required this.name,
    required this.lat,
    required this.lng,
    this.elevationM = 800,
  });
}

class RoadEdge {
  final String fromId;
  final String toId;
  final double distanceKm;
  final String roadType; // 'highway', 'primary', 'secondary', 'desert_track'
  final double baseSpeedKmH;
  final List<LatLng> intermediateCoords;
  final double inclinePercent; // Grade percentage (e.g. +6.5% incline, -4.2% descent)

  const RoadEdge({
    required this.fromId,
    required this.toId,
    required this.distanceKm,
    required this.roadType,
    required this.baseSpeedKmH,
    this.intermediateCoords = const [],
    this.inclinePercent = 0.0,
  });
}

class OfflineRoutePlan {
  final List<LatLng> polylinePoints;
  final double totalDistanceKm;
  final double estimatedDurationMinutes;
  final TacticalVehicleProfile profile;
  final List<String> tacticalWaypoints;
  final bool isOffline;
  final int elevationGainMeters;
  final int elevationLossMeters;
  final double averageInclinePercent;
  final double maxInclinePercent;

  const OfflineRoutePlan({
    required this.polylinePoints,
    required this.totalDistanceKm,
    required this.estimatedDurationMinutes,
    required this.profile,
    required this.tacticalWaypoints,
    this.isOffline = true,
    this.elevationGainMeters = 0,
    this.elevationLossMeters = 0,
    this.averageInclinePercent = 0.0,
    this.maxInclinePercent = 0.0,
  });

  String get inclineSummaryArabic {
    if (maxInclinePercent.abs() > 7.0) {
      return 'انحدار حاد / عقبة جبلية (${maxInclinePercent.abs().toStringAsFixed(1)}%) • صعود +$elevationGainMeters م / هبوط -$elevationLossMeters م';
    } else if (maxInclinePercent.abs() > 3.5) {
      return 'انحدار معتدل (${maxInclinePercent.abs().toStringAsFixed(1)}%) • صعود +$elevationGainMeters م';
    } else {
      return 'طريق مستوٍ (${maxInclinePercent.abs().toStringAsFixed(1)}%) • تضاريس مريحة';
    }
  }
}

/// 100% On-Device Tactical Routing Engine for Jordan with Elevation & Slope Analysis
class OfflineRoutingEngine {
  static final Map<String, RoadNode> _nodes = {};
  static final Map<String, List<RoadEdge>> _adjacency = {};
  static bool _isInitialized = false;

  static void initialize() {
    if (_isInitialized) return;

    // ── Strategic Road Network Nodes Across Jordan with Elevation (DEM) ──
    final nodeList = const [
      // Amman Urban Hubs
      RoadNode(id: 'amm_center', name: 'وسط عمان / العبدلي', lat: 31.9615, lng: 35.9130, elevationM: 760),
      RoadNode(id: 'amm_dabouq', name: 'دابوق / قاعدة القيادة الغربية', lat: 31.9960, lng: 35.8285, elevationM: 1045),
      RoadNode(id: 'amm_7th', name: 'الدوار السابع / طريق المطار', lat: 31.9530, lng: 35.8580, elevationM: 920),
      RoadNode(id: 'amm_tabarbour', name: 'طبربور / اتوستراد الزرقاء', lat: 31.9920, lng: 35.9450, elevationM: 880),
      RoadNode(id: 'amm_airport', name: 'مطار الملكة علياء الدولي (الجيزة)', lat: 31.7200, lng: 35.9880, elevationM: 720),

      // Desert Highway Corridor (Route 15 - الطريق الصحراوي الرئيسي)
      RoadNode(id: 'dabaa', name: 'محطة ضبعة / الطريق الصحراوي', lat: 31.5420, lng: 36.0150, elevationM: 700),
      RoadNode(id: 'qatrana', name: 'القطرانة / جسر القطرانة العسكري', lat: 31.2450, lng: 36.0420, elevationM: 790),
      RoadNode(id: 'sultani', name: 'محطة السلطاني / سد السلطاني', lat: 31.0520, lng: 35.9980, elevationM: 820),
      RoadNode(id: 'hasa', name: 'الحسا / مناجم الفوسفات والتقاطع', lat: 30.8200, lng: 35.9750, elevationM: 840),
      RoadNode(id: 'jurf', name: 'جرف الدراويش / الخط الحديدي الحجازي', lat: 30.6850, lng: 35.8650, elevationM: 930),
      RoadNode(id: 'husseiniya', name: 'الحسينية / البادية الجنوبية', lat: 30.4920, lng: 35.7980, elevationM: 1050),
      RoadNode(id: 'maan_city', name: 'معان / مثلث الشيدية وقاعدة معان', lat: 30.1920, lng: 35.7320, elevationM: 1070),
      RoadNode(id: 'ras_naqb', name: 'نقب الرملة / رأس النقب الاستراتيجي', lat: 29.9850, lng: 35.4850, elevationM: 1570),
      RoadNode(id: 'quwayra', name: 'القويرة / مدخل وادي رم', lat: 29.8050, lng: 35.3120, elevationM: 800),
      RoadNode(id: 'aqaba_port', name: 'ميناء العقبة الجنوبي / الساحل', lat: 29.4120, lng: 34.9810, elevationM: 15),

      // King's Highway Corridor (Route 35 - الطريق الملوكي الجبلي)
      RoadNode(id: 'madaba_nebo', name: 'مادبا / جبل نيبو', lat: 31.7450, lng: 35.7750, elevationM: 780),
      RoadNode(id: 'dhiban_mujib', name: 'ذيبان / وادي الموجب الشاهق', lat: 31.5020, lng: 35.7820, elevationM: 720),
      RoadNode(id: 'qasr_karak', name: 'القصر / شمال الكرك', lat: 31.3150, lng: 35.7480, elevationM: 920),
      RoadNode(id: 'karak_castle', name: 'قلعة الكرك / مؤتة والمزار', lat: 31.1810, lng: 35.7020, elevationM: 980),
      RoadNode(id: 'tafila_ais', name: 'الطفيلة / جبل العيص', lat: 30.8420, lng: 35.6180, elevationM: 1260),
      RoadNode(id: 'rashadiya_dana', name: 'الرشادية / مطل ضانا العالي', lat: 30.6870, lng: 35.6110, elevationM: 1480),
      RoadNode(id: 'shoubak_castle', name: 'قلعة الشوبك / الهضبة الجنوبية', lat: 30.5315, lng: 35.5610, elevationM: 1330),
      RoadNode(id: 'petra_wadi_musa', name: 'البتراء / وادي موسى وجبل هارون', lat: 30.3200, lng: 35.4750, elevationM: 1150),
      RoadNode(id: 'wadi_rum', name: 'محمية وادي رم / رم والديسة', lat: 29.5740, lng: 35.4190, elevationM: 950),

      // Dead Sea & Jordan Valley Corridor (Route 65 - طريق الأغوار والبحر الميت)
      RoadNode(id: 'dead_sea_north', name: 'شمال البحر الميت / السويمة', lat: 31.7200, lng: 35.5800, elevationM: -390),
      RoadNode(id: 'zara_hotsprings', name: 'منطقة الزارة / شاطئ البحر الميت', lat: 31.5950, lng: 35.5620, elevationM: -420),
      RoadNode(id: 'ghor_safi', name: 'غور الصافي / مصانع البوتاس', lat: 31.0350, lng: 35.4850, elevationM: -385),
      RoadNode(id: 'feifa_araba', name: 'فيفا / وادي عربة الأوسط', lat: 30.7250, lng: 35.3950, elevationM: -180),
      RoadNode(id: 'rahma_border', name: 'الرحمة / طريق وادي عربة الجنوبي', lat: 29.9150, lng: 35.1520, elevationM: 90),

      // Zarqa & Eastern Desert Corridor (Route 30 - طريق الأزرق وبغداد الدولي)
      RoadNode(id: 'zrq_city', name: 'الزرقاء / الهاشمية ومعسكرات الجيش', lat: 32.0720, lng: 36.0880, elevationM: 610),
      RoadNode(id: 'azraq_junction', name: 'تقاطع مثلث الأزرق / واحة الأزرق', lat: 31.8380, lng: 36.8120, elevationM: 520),
      RoadNode(id: 'azraq_airbase', name: 'قاعدة الشهيد موفق السلطي الجوية', lat: 31.8320, lng: 36.7860, elevationM: 515),
      RoadNode(id: 'safawi', name: 'الصفاوي / تقاطع طريق بغداد', lat: 32.2010, lng: 37.1230, elevationM: 680),
      RoadNode(id: 'ruwaished', name: 'الرويشد / طريبيل والحدود الشرقية', lat: 32.5020, lng: 38.2040, elevationM: 700),

      // North Strategic Corridor (Jerash, Ajloun, Irbid, Mafraq)
      RoadNode(id: 'salt_city', name: 'السلط / جبال البلقاء', lat: 32.0390, lng: 35.7280, elevationM: 850),
      RoadNode(id: 'jerash', name: 'جرش / جسر سيل جرش', lat: 32.2780, lng: 35.8950, elevationM: 580),
      RoadNode(id: 'ajloun', name: 'عجلون / قلعة الربض وغابات عجلون', lat: 32.3250, lng: 35.7350, elevationM: 1100),
      RoadNode(id: 'irbid_city', name: 'إربد / جامعة اليرموك والمركز', lat: 32.5450, lng: 35.8550, elevationM: 620),
      RoadNode(id: 'ramtha', name: 'الرمثا / الحدود الشمالية السورية', lat: 32.5580, lng: 36.0120, elevationM: 540),
      RoadNode(id: 'um_qais', name: 'أم قيس / مطل اليرموك والجولان', lat: 32.6535, lng: 35.6820, elevationM: 370),
      RoadNode(id: 'mafraq_airbase', name: 'قاعدة الملك حسين الجوية (المفرق)', lat: 32.3560, lng: 36.2590, elevationM: 700),
      RoadNode(id: 'jaber_border', name: 'مركز حدود جابر / درعا', lat: 32.5180, lng: 36.3150, elevationM: 580),
    ];

    for (final node in nodeList) {
      _nodes[node.id] = node;
      _adjacency[node.id] = [];
    }

    void addEdge(String u, String v, double distKm, String type, double speed, [List<LatLng>? coords]) {
      final n1 = _nodes[u]!;
      final n2 = _nodes[v]!;
      final p1 = LatLng(n1.lat, n1.lng);
      final p2 = LatLng(n2.lat, n2.lng);

      final dense = coords ?? _generateDenseRoadCurve(p1, p2, distKm);

      // Incline % = (Elevation Change in meters / Distance in meters) * 100
      final elevDiffM = n2.elevationM - n1.elevationM;
      final distM = distKm * 1000.0;
      final incline = (elevDiffM / (distM > 0 ? distM : 1000.0)) * 100.0;

      _adjacency[u]?.add(RoadEdge(
        fromId: u,
        toId: v,
        distanceKm: distKm,
        roadType: type,
        baseSpeedKmH: speed,
        intermediateCoords: dense,
        inclinePercent: double.parse(incline.toStringAsFixed(1)),
      ));

      _adjacency[v]?.add(RoadEdge(
        fromId: v,
        toId: u,
        distanceKm: distKm,
        roadType: type,
        baseSpeedKmH: speed,
        intermediateCoords: dense.reversed.toList(),
        inclinePercent: double.parse((-incline).toStringAsFixed(1)),
      ));
    }

    // 1. Amman Ring & Arterials
    addEdge('amm_dabouq', 'amm_center', 11.0, 'primary', 65.0);
    addEdge('amm_dabouq', 'amm_7th', 9.5, 'primary', 70.0);
    addEdge('amm_center', 'amm_7th', 8.0, 'primary', 60.0);
    addEdge('amm_center', 'amm_tabarbour', 10.0, 'primary', 60.0);
    addEdge('amm_tabarbour', 'zrq_city', 18.0, 'highway', 85.0);
    addEdge('amm_7th', 'amm_airport', 28.0, 'highway', 100.0);
    addEdge('amm_dabouq', 'salt_city', 16.0, 'primary', 65.0);
    addEdge('amm_7th', 'madaba_nebo', 26.0, 'primary', 75.0);
    addEdge('salt_city', 'dead_sea_north', 32.0, 'secondary', 55.0);

    // 2. Desert Highway 15 (Amman -> Aqaba with Ras Naqb Grade)
    addEdge('amm_airport', 'dabaa', 22.0, 'highway', 105.0);
    addEdge('dabaa', 'qatrana', 36.0, 'highway', 105.0);
    addEdge('qatrana', 'sultani', 24.0, 'highway', 105.0);
    addEdge('sultani', 'hasa', 26.0, 'highway', 105.0);
    addEdge('hasa', 'jurf', 21.0, 'highway', 105.0);
    addEdge('jurf', 'husseiniya', 24.0, 'highway', 105.0);
    addEdge('husseiniya', 'maan_city', 35.0, 'highway', 105.0);
    addEdge('maan_city', 'ras_naqb', 38.0, 'highway', 95.0); // +500m ascent to Naqb
    addEdge('ras_naqb', 'quwayra', 26.0, 'highway', 95.0); // -770m steep descent
    addEdge('quwayra', 'aqaba_port', 48.0, 'highway', 95.0); // -785m to Sea Level

    // 3. King's Highway 35 (Scenic Mountain Pass & Canyons)
    addEdge('madaba_nebo', 'dhiban_mujib', 32.0, 'secondary', 55.0);
    addEdge('dhiban_mujib', 'qasr_karak', 28.0, 'secondary', 50.0); // Mujib Canyon Gorge
    addEdge('qasr_karak', 'karak_castle', 18.0, 'secondary', 60.0);
    addEdge('qatrana', 'karak_castle', 36.0, 'primary', 75.0);
    addEdge('karak_castle', 'tafila_ais', 46.0, 'secondary', 50.0);
    addEdge('hasa', 'tafila_ais', 32.0, 'primary', 65.0);
    addEdge('tafila_ais', 'rashadiya_dana', 22.0, 'secondary', 50.0); // High Dana Pass (1480m)
    addEdge('rashadiya_dana', 'shoubak_castle', 19.0, 'secondary', 55.0);
    addEdge('shoubak_castle', 'petra_wadi_musa', 26.0, 'secondary', 50.0);
    addEdge('maan_city', 'shoubak_castle', 42.0, 'secondary', 65.0);
    addEdge('maan_city', 'petra_wadi_musa', 38.0, 'primary', 70.0);
    addEdge('quwayra', 'wadi_rum', 28.0, 'desert_track', 60.0);
    addEdge('petra_wadi_musa', 'wadi_rum', 85.0, 'desert_track', 60.0);

    // 4. Dead Sea & Jordan Valley Highway 65 (Lowest Point on Earth)
    addEdge('dead_sea_north', 'zara_hotsprings', 16.0, 'highway', 85.0);
    addEdge('zara_hotsprings', 'ghor_safi', 64.0, 'highway', 85.0);
    addEdge('karak_castle', 'ghor_safi', 34.0, 'secondary', 50.0); // Extreme -1365m Descent
    addEdge('ghor_safi', 'feifa_araba', 38.0, 'highway', 90.0);
    addEdge('tafila_ais', 'feifa_araba', 42.0, 'secondary', 45.0); // Steep Wadi Feifa
    addEdge('feifa_araba', 'rahma_border', 92.0, 'highway', 95.0);
    addEdge('rahma_border', 'aqaba_port', 28.0, 'highway', 90.0);

    // 5. Eastern Desert & Baghdad Highway 30
    addEdge('zrq_city', 'azraq_junction', 78.0, 'highway', 95.0);
    addEdge('azraq_junction', 'azraq_airbase', 8.0, 'primary', 75.0);
    addEdge('amm_airport', 'azraq_junction', 76.0, 'primary', 85.0);
    addEdge('azraq_junction', 'safawi', 55.0, 'desert_track', 65.0);
    addEdge('safawi', 'ruwaished', 130.0, 'highway', 95.0);

    // 6. North Highway 25/35 & Mafraq Corridor
    addEdge('amm_dabouq', 'jerash', 38.0, 'highway', 90.0);
    addEdge('jerash', 'ajloun', 22.0, 'secondary', 50.0);
    addEdge('jerash', 'irbid_city', 35.0, 'highway', 90.0);
    addEdge('ajloun', 'irbid_city', 28.0, 'secondary', 55.0);
    addEdge('irbid_city', 'ramtha', 18.0, 'primary', 80.0);
    addEdge('irbid_city', 'um_qais', 28.0, 'secondary', 60.0);
    addEdge('zrq_city', 'mafraq_airbase', 38.0, 'highway', 90.0);
    addEdge('mafraq_airbase', 'ramtha', 32.0, 'primary', 80.0);
    addEdge('mafraq_airbase', 'jaber_border', 22.0, 'primary', 80.0);
    addEdge('mafraq_airbase', 'safawi', 85.0, 'primary', 85.0);

    _isInitialized = true;
  }

  static List<LatLng> _generateDenseRoadCurve(LatLng p1, LatLng p2, double distanceKm) {
    final list = <LatLng>[p1];
    final steps = math.max(4, (distanceKm / 5.0).round());

    for (int i = 1; i < steps; i++) {
      final t = i / steps;
      final lat = p1.latitude + (p2.latitude - p1.latitude) * t;
      final lng = p1.longitude + (p2.longitude - p1.longitude) * t;
      final offset = math.sin(t * math.pi) * 0.003;
      list.add(LatLng(lat + offset, lng - (offset * 0.5)));
    }

    list.add(p2);
    return list;
  }

  static RoadNode findNearestNode(double lat, double lng) {
    initialize();
    RoadNode nearest = _nodes.values.first;
    double minDistance = double.infinity;

    for (final node in _nodes.values) {
      final d = _haversineDistanceKm(lat, lng, node.lat, node.lng);
      if (d < minDistance) {
        minDistance = d;
        nearest = node;
      }
    }
    return nearest;
  }

  static OfflineRoutePlan calculateOnDeviceRoute({
    required LatLng start,
    required LatLng destination,
    TacticalVehicleProfile profile = TacticalVehicleProfile.convoy,
  }) {
    initialize();

    final startNode = findNearestNode(start.latitude, start.longitude);
    final endNode = findNearestNode(destination.latitude, destination.longitude);

    if (startNode.id == endNode.id) {
      return OfflineRoutePlan(
        polylinePoints: [start, destination],
        totalDistanceKm: _haversineDistanceKm(start.latitude, start.longitude, destination.latitude, destination.longitude),
        estimatedDurationMinutes: 5.0,
        profile: profile,
        tacticalWaypoints: [startNode.name],
        isOffline: true,
      );
    }

    final openSet = <String>{startNode.id};
    final cameFrom = <String, RoadEdge>{};
    final gScore = <String, double>{for (var k in _nodes.keys) k: double.infinity};
    final fScore = <String, double>{for (var k in _nodes.keys) k: double.infinity};

    gScore[startNode.id] = 0.0;
    fScore[startNode.id] = _haversineDistanceKm(startNode.lat, startNode.lng, endNode.lat, endNode.lng);

    double speedMultiplier;
    switch (profile) {
      case TacticalVehicleProfile.convoy:
        speedMultiplier = 0.65;
        break;
      case TacticalVehicleProfile.offroad4x4:
        speedMultiplier = 1.0;
        break;
      case TacticalVehicleProfile.armored:
        speedMultiplier = 0.50;
        break;
      case TacticalVehicleProfile.rapidResponse:
        speedMultiplier = 1.25;
        break;
    }

    while (openSet.isNotEmpty) {
      String current = openSet.reduce((a, b) => (fScore[a] ?? double.infinity) < (fScore[b] ?? double.infinity) ? a : b);

      if (current == endNode.id) {
        return _reconstructPath(cameFrom, current, start, destination, profile, speedMultiplier);
      }

      openSet.remove(current);
      final neighbors = _adjacency[current] ?? [];

      for (final edge in neighbors) {
        double edgePenalty = 1.0;
        if (edge.roadType == 'desert_track' && profile == TacticalVehicleProfile.convoy) {
          edgePenalty = 1.8;
        }

        // Heavy vehicles penalty on steep mountain inclines (> 6%)
        if (edge.inclinePercent > 6.0 && (profile == TacticalVehicleProfile.convoy || profile == TacticalVehicleProfile.armored)) {
          edgePenalty *= 1.4;
        }

        final tentativeG = (gScore[current] ?? double.infinity) + (edge.distanceKm * edgePenalty);

        if (tentativeG < (gScore[edge.toId] ?? double.infinity)) {
          cameFrom[edge.toId] = edge;
          gScore[edge.toId] = tentativeG;
          final h = _haversineDistanceKm(_nodes[edge.toId]!.lat, _nodes[edge.toId]!.lng, endNode.lat, endNode.lng);
          fScore[edge.toId] = tentativeG + h;
          openSet.add(edge.toId);
        }
      }
    }

    final dist = _haversineDistanceKm(start.latitude, start.longitude, destination.latitude, destination.longitude);
    return OfflineRoutePlan(
      polylinePoints: [start, destination],
      totalDistanceKm: double.parse(dist.toStringAsFixed(1)),
      estimatedDurationMinutes: double.parse(((dist / 60.0) * 60.0 / speedMultiplier).toStringAsFixed(0)),
      profile: profile,
      tacticalWaypoints: [startNode.name, endNode.name],
      isOffline: true,
    );
  }

  static OfflineRoutePlan _reconstructPath(
    Map<String, RoadEdge> cameFrom,
    String current,
    LatLng start,
    LatLng destination,
    TacticalVehicleProfile profile,
    double speedMultiplier,
  ) {
    final points = <LatLng>[];
    final waypoints = <String>[_nodes[current]!.name];
    double totalDistance = 0.0;
    double totalTimeHours = 0.0;

    int totalAscentM = 0;
    int totalDescentM = 0;
    double maxIncline = 0.0;

    String curr = current;
    final edges = <RoadEdge>[];

    while (cameFrom.containsKey(curr)) {
      final edge = cameFrom[curr]!;
      edges.add(edge);
      curr = edge.fromId;
      waypoints.add(_nodes[curr]!.name);
    }

    points.add(start);
    for (final edge in edges.reversed) {
      totalDistance += edge.distanceKm;
      final speed = edge.baseSpeedKmH * speedMultiplier;
      totalTimeHours += (edge.distanceKm / (speed > 0 ? speed : 40.0));
      points.addAll(edge.intermediateCoords);

      final nFrom = _nodes[edge.fromId]!;
      final nTo = _nodes[edge.toId]!;
      final diff = nTo.elevationM - nFrom.elevationM;
      if (diff > 0) totalAscentM += diff;
      if (diff < 0) totalDescentM += diff.abs();

      if (edge.inclinePercent.abs() > maxIncline.abs()) {
        maxIncline = edge.inclinePercent;
      }
    }
    points.add(destination);

    final avgIncline = totalDistance > 0 ? ((totalAscentM - totalDescentM) / (totalDistance * 1000.0)) * 100.0 : 0.0;

    return OfflineRoutePlan(
      polylinePoints: points,
      totalDistanceKm: double.parse(totalDistance.toStringAsFixed(1)),
      estimatedDurationMinutes: double.parse((totalTimeHours * 60.0).toStringAsFixed(0)),
      profile: profile,
      tacticalWaypoints: waypoints.reversed.toList(),
      isOffline: true,
      elevationGainMeters: totalAscentM,
      elevationLossMeters: totalDescentM,
      averageInclinePercent: double.parse(avgIncline.toStringAsFixed(1)),
      maxInclinePercent: double.parse(maxIncline.toStringAsFixed(1)),
    );
  }

  static double _haversineDistanceKm(double lat1, double lon1, double lat2, double lon2) {
    const r = 6371.0;
    final dLat = (lat2 - lat1) * (math.pi / 180.0);
    final dLon = (lon2 - lon1) * (math.pi / 180.0);
    final a = math.sin(dLat / 2) * math.sin(dLat / 2) +
        math.cos(lat1 * (math.pi / 180.0)) *
            math.cos(lat2 * (math.pi / 180.0)) *
            math.sin(dLon / 2) *
            math.sin(dLon / 2);
    final c = 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a));
    return r * c;
  }
}