import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:em2rp/models/equipment_model.dart';
import 'package:em2rp/models/container_model.dart';
import 'package:em2rp/models/alert_model.dart';
import 'package:em2rp/models/maintenance_model.dart';
import 'package:em2rp/services/api_service.dart';
import 'package:em2rp/services/data_service.dart';

class EquipmentService {
  final FirebaseFirestore _firestore = FirebaseFirestore.instance;
  final ApiService _apiService = apiService;
  final DataService _dataService = DataService(apiService);

  // Collection references (utilisées seulement pour les lectures)
  CollectionReference get _equipmentCollection => _firestore.collection('equipments');

  // ============================================================================
  // CRUD Operations - Utilise le backend sécurisé
  // ============================================================================

  /// Créer un nouvel équipement (via Cloud Function)
  Future<void> createEquipment(EquipmentModel equipment) async {
    try {
      await _apiService.call('createEquipment', equipment.toMap()..['id'] = equipment.id);
    } catch (e) {
      print('Error creating equipment: $e');
      rethrow;
    }
  }

  /// Mettre à jour un équipement (via Cloud Function)
  Future<void> updateEquipment(String id, Map<String, dynamic> data) async {
    try {
      await _apiService.call('updateEquipment', {
        'equipmentId': id,
        'data': data,
      });
    } catch (e) {
      print('Error updating equipment: $e');
      rethrow;
    }
  }

  /// Supprimer un équipement (via Cloud Function)
  Future<void> deleteEquipment(String id) async {
    try {
      await _apiService.call('deleteEquipment', {'equipmentId': id});
    } catch (e) {
      print('Error deleting equipment: $e');
      rethrow;
    }
  }

  // ============================================================================
  // READ Operations - Utilise Firestore streams (temps réel)
  // ============================================================================

  /// Récupérer un équipement par ID
  Future<EquipmentModel?> getEquipmentById(String id) async {
    try {
      final doc = await _equipmentCollection.doc(id).get();
      if (doc.exists) {
        return EquipmentModel.fromMap(doc.data() as Map<String, dynamic>, doc.id);
      }
      return null;
    } catch (e) {
      print('Error getting equipment: $e');
      rethrow;
    }
  }

  /// Récupérer les équipements avec filtres (stream temps réel)
  Stream<List<EquipmentModel>> getEquipment({
    EquipmentCategory? category,
    EquipmentStatus? status,
    String? model,
    String? searchQuery,
  }) {
    try {
      Query query = _equipmentCollection;

      // Filtre par catégorie
      if (category != null) {
        query = query.where('category', isEqualTo: equipmentCategoryToString(category));
      }

      // Filtre par statut
      if (status != null) {
        query = query.where('status', isEqualTo: equipmentStatusToString(status));
      }

      // Filtre par modèle
      if (model != null && model.isNotEmpty) {
        query = query.where('model', isEqualTo: model);
      }

      return query.snapshots().map((snapshot) {
        List<EquipmentModel> equipmentList = snapshot.docs
            .map((doc) => EquipmentModel.fromMap(doc.data() as Map<String, dynamic>, doc.id))
            .toList();

        // Filtre par recherche texte (côté client car Firestore ne supporte pas les recherches texte complexes)
        if (searchQuery != null && searchQuery.isNotEmpty) {
          final lowerSearch = searchQuery.toLowerCase();
          equipmentList = equipmentList.where((equipment) {
            return equipment.name.toLowerCase().contains(lowerSearch) ||
                   (equipment.model?.toLowerCase().contains(lowerSearch) ?? false) ||
                   equipment.id.toLowerCase().contains(lowerSearch);
          }).toList();
        }

        return equipmentList;
      });
    } catch (e) {
      print('Error streaming equipment: $e');
      rethrow;
    }
  }

  // ============================================================================
  // Availability & Stock Management - Logique métier côté client
  // ============================================================================

  /// Vérifier la disponibilité d'un équipement pour une période donnée
  Future<List<String>> checkAvailability(
    String equipmentId,
    DateTime startDate,
    DateTime endDate,
  ) async {
    try {
      final conflicts = <String>[];

      // Récupérer tous les événements qui chevauchent la période
      final eventsQuery = await _firestore.collection('events')
          .where('StartDateTime', isLessThanOrEqualTo: Timestamp.fromDate(endDate))
          .where('EndDateTime', isGreaterThanOrEqualTo: Timestamp.fromDate(startDate))
          .get();

      for (var eventDoc in eventsQuery.docs) {
        final eventData = eventDoc.data();
        final assignedEquipmentRaw = eventData['assignedEquipment'] ?? [];

        if (assignedEquipmentRaw is List) {
          for (var eq in assignedEquipmentRaw) {
            if (eq is Map && eq['equipmentId'] == equipmentId) {
              conflicts.add(eventDoc.id);
              break;
            }
          }
        }
      }

      return conflicts;
    } catch (e) {
      print('Error checking availability: $e');
      rethrow;
    }
  }

  /// Trouver des alternatives (même modèle) disponibles
  Future<List<EquipmentModel>> findAlternatives(
    String model,
    DateTime startDate,
    DateTime endDate,
  ) async {
    try {
      // Récupérer tous les équipements du même modèle
      final equipmentQuery = await _firestore.collection('equipments')
          .where('model', isEqualTo: model)
          .get();

      final alternatives = <EquipmentModel>[];

      for (var doc in equipmentQuery.docs) {
        final equipment = EquipmentModel.fromMap(
          doc.data(),
          doc.id,
        );

        // Vérifier la disponibilité
        final conflicts = await checkAvailability(equipment.id, startDate, endDate);

        if (conflicts.isEmpty && equipment.status == EquipmentStatus.available) {
          alternatives.add(equipment);
        }
      }

      return alternatives;
    } catch (e) {
      print('Error finding alternatives: $e');
      rethrow;
    }
  }

  /// Mettre à jour le stock d'un consommable/câble
  Future<void> updateStock(String id, int quantityChange) async {
    try {
      final equipment = await getEquipmentById(id);
      if (equipment == null) {
        throw Exception('Equipment not found');
      }

      if (!equipment.hasQuantity) {
        throw Exception('Equipment does not have quantity tracking');
      }

      final newAvailableQuantity = (equipment.availableQuantity ?? 0) + quantityChange;

      await updateEquipment(id, {
        'availableQuantity': newAvailableQuantity,
      });

      // Vérifier si le seuil critique est atteint
      if (equipment.criticalThreshold != null &&
          newAvailableQuantity <= equipment.criticalThreshold!) {
        await _createLowStockAlert(equipment);
      }
    } catch (e) {
      print('Error updating stock: $e');
      rethrow;
    }
  }

  /// Vérifier les stocks critiques et créer des alertes
  Future<void> checkCriticalStock() async {
    try {
      final equipmentQuery = await _firestore.collection('equipments')
          .where('category', whereIn: [
            equipmentCategoryToString(EquipmentCategory.consumable),
            equipmentCategoryToString(EquipmentCategory.cable),
          ])
          .get();

      for (var doc in equipmentQuery.docs) {
        final equipment = EquipmentModel.fromMap(
          doc.data(),
          doc.id,
        );

        if (equipment.isCriticalStock) {
          await _createLowStockAlert(equipment);
        }
      }
    } catch (e) {
      print('Error checking critical stock: $e');
      rethrow;
    }
  }

  /// Créer une alerte de stock faible
  Future<void> _createLowStockAlert(EquipmentModel equipment) async {
    try {
      // Vérifier si une alerte existe déjà pour cet équipement
      final existingAlerts = await _firestore.collection('alerts')
          .where('equipmentId', isEqualTo: equipment.id)
          .where('type', isEqualTo: alertTypeToString(AlertType.lowStock))
          .where('isRead', isEqualTo: false)
          .get();

      if (existingAlerts.docs.isEmpty) {
        final alert = AlertModel(
          id: _firestore.collection('alerts').doc().id,
          type: AlertType.lowStock,
          message: 'Stock critique pour ${equipment.name} (${equipment.model ?? ""}): ${equipment.availableQuantity}/${equipment.criticalThreshold}',
          equipmentId: equipment.id,
          createdAt: DateTime.now(),
        );

        await _firestore.collection('alerts').doc(alert.id).set(alert.toMap());
      }
    } catch (e) {
      print('Error creating low stock alert: $e');
      rethrow;
    }
  }

  /// Générer les données du QR code (ID de l'équipement)
  String generateQRCodeData(String equipmentId) {
    // Pour l'instant, on retourne simplement l'ID
    // On pourrait aussi générer une URL complète : https://app.em2events.fr/equipment/$equipmentId
    return equipmentId;
  }

  /// Récupérer tous les modèles uniques (pour l'indexation/autocomplete)
  Future<List<String>> getAllModels() async {
    try {
      final equipmentQuery = await _firestore.collection('equipments').get();
      final models = <String>{};

      for (var doc in equipmentQuery.docs) {
        final data = doc.data();
        final model = data['model'] as String?;
        if (model != null && model.isNotEmpty) {
          models.add(model);
        }
      }

      return models.toList()..sort();
    } catch (e) {
      print('Error getting all models: $e');
      rethrow;
    }
  }

  /// Récupérer toutes les marques uniques (pour l'indexation/autocomplete)
  Future<List<String>> getAllBrands() async {
    try {
      final equipmentQuery = await _firestore.collection('equipments').get();
      final brands = <String>{};

      for (var doc in equipmentQuery.docs) {
        final data = doc.data();
        final brand = data['brand'] as String?;
        if (brand != null && brand.isNotEmpty) {
          brands.add(brand);
        }
      }

      return brands.toList()..sort();
    } catch (e) {
      print('Error getting all brands: $e');
      rethrow;
    }
  }

  /// Récupérer les modèles filtrés par marque
  Future<List<String>> getModelsByBrand(String brand) async {
    try {
      final equipmentQuery = await _firestore.collection('equipments')
          .where('brand', isEqualTo: brand)
          .get();
      final models = <String>{};

      for (var doc in equipmentQuery.docs) {
        final data = doc.data();
        final model = data['model'] as String?;
        if (model != null && model.isNotEmpty) {
          models.add(model);
        }
      }

      return models.toList()..sort();
    } catch (e) {
      print('Error getting models by brand: $e');
      rethrow;
    }
  }

  /// Vérifier si un ID existe déjà
  Future<bool> isIdUnique(String id) async {
    try {
      final doc = await _firestore.collection('equipments').doc(id).get();
      return !doc.exists;
    } catch (e) {
      print('Error checking ID uniqueness: $e');
      rethrow;
    }
  }

  /// Récupérer toutes les boîtes/containers disponibles
  Future<List<ContainerModel>> getBoxes() async {
    try {
      final containersData = await _dataService.getContainers();

      final boxes = <ContainerModel>[];
      for (var data in containersData) {
        final id = data['id'] as String;
        final container = ContainerModel.fromMap(data, id);
        boxes.add(container);
      }

      return boxes;
    } catch (e) {
      print('Error getting boxes: $e');
      rethrow;
    }
  }

  /// Récupérer plusieurs équipements par leurs IDs
  Future<List<EquipmentModel>> getEquipmentsByIds(List<String> ids) async {
    try {
      if (ids.isEmpty) return [];

      final equipments = <EquipmentModel>[];

      // Firestore limite les requêtes whereIn à 10 éléments
      // On doit donc diviser en plusieurs requêtes si nécessaire
      for (int i = 0; i < ids.length; i += 10) {
        final batch = ids.skip(i).take(10).toList();
        final query = await _firestore.collection('equipments')
            .where(FieldPath.documentId, whereIn: batch)
            .get();

        for (var doc in query.docs) {
          equipments.add(
            EquipmentModel.fromMap(
              doc.data(),
              doc.id,
            ),
          );
        }
      }

      return equipments;
    } catch (e) {
      print('Error getting equipments by IDs: $e');
      rethrow;
    }
  }

  /// Récupérer les maintenances pour un équipement
  Future<List<MaintenanceModel>> getMaintenancesForEquipment(String equipmentId) async {
    try {
      final maintenanceQuery = await _firestore
          .collection('maintenances')
          .where('equipmentIds', arrayContains: equipmentId)
          .orderBy('scheduledDate', descending: true)
          .get();

      final maintenances = <MaintenanceModel>[];
      for (var doc in maintenanceQuery.docs) {
        maintenances.add(
          MaintenanceModel.fromMap(
            doc.data(),
            doc.id,
          ),
        );
      }

      return maintenances;
    } catch (e) {
      print('Error getting maintenances for equipment: $e');
      rethrow;
    }
  }
}