import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:em2rp/models/equipment_model.dart';
import 'package:em2rp/models/alert_model.dart';

class EquipmentService {
  final FirebaseFirestore _firestore = FirebaseFirestore.instance;

  // Collection references
  CollectionReference get _equipmentCollection => _firestore.collection('equipments');
  CollectionReference get _alertsCollection => _firestore.collection('alerts');
  CollectionReference get _eventsCollection => _firestore.collection('events');

  // CRUD Operations

  /// Créer un nouvel équipement
  Future<void> createEquipment(EquipmentModel equipment) async {
    try {
      await _equipmentCollection.doc(equipment.id).set(equipment.toMap());
    } catch (e) {
      print('Error creating equipment: $e');
      rethrow;
    }
  }

  /// Mettre à jour un équipement
  Future<void> updateEquipment(String id, Map<String, dynamic> data) async {
    try {
      data['updatedAt'] = Timestamp.fromDate(DateTime.now());
      await _equipmentCollection.doc(id).update(data);
    } catch (e) {
      print('Error updating equipment: $e');
      rethrow;
    }
  }

  /// Supprimer un équipement
  Future<void> deleteEquipment(String id) async {
    try {
      await _equipmentCollection.doc(id).delete();
    } catch (e) {
      print('Error deleting equipment: $e');
      rethrow;
    }
  }

  /// 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<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;
    }
  }

  /// 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 _eventsCollection
          .where('StartDateTime', isLessThanOrEqualTo: Timestamp.fromDate(endDate))
          .where('EndDateTime', isGreaterThanOrEqualTo: Timestamp.fromDate(startDate))
          .get();

      for (var eventDoc in eventsQuery.docs) {
        final eventData = eventDoc.data() as Map<String, dynamic>;
        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 _equipmentCollection
          .where('model', isEqualTo: model)
          .get();

      final alternatives = <EquipmentModel>[];

      for (var doc in equipmentQuery.docs) {
        final equipment = EquipmentModel.fromMap(
          doc.data() as Map<String, dynamic>,
          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 _equipmentCollection
          .where('category', whereIn: [
            equipmentCategoryToString(EquipmentCategory.consumable),
            equipmentCategoryToString(EquipmentCategory.cable),
          ])
          .get();

      for (var doc in equipmentQuery.docs) {
        final equipment = EquipmentModel.fromMap(
          doc.data() as Map<String, dynamic>,
          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 _alertsCollection
          .where('equipmentId', isEqualTo: equipment.id)
          .where('type', isEqualTo: alertTypeToString(AlertType.lowStock))
          .where('isRead', isEqualTo: false)
          .get();

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

        await _alertsCollection.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 _equipmentCollection.get();
      final models = <String>{};

      for (var doc in equipmentQuery.docs) {
        final data = doc.data() as Map<String, dynamic>;
        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 _equipmentCollection.get();
      final brands = <String>{};

      for (var doc in equipmentQuery.docs) {
        final data = doc.data() as Map<String, dynamic>;
        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 _equipmentCollection
          .where('brand', isEqualTo: brand)
          .get();
      final models = <String>{};

      for (var doc in equipmentQuery.docs) {
        final data = doc.data() as Map<String, dynamic>;
        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 _equipmentCollection.doc(id).get();
      return !doc.exists;
    } catch (e) {
      print('Error checking ID uniqueness: $e');
      rethrow;
    }
  }

  /// Récupérer toutes les boîtes (équipements qui peuvent contenir d'autres équipements)
  Future<List<EquipmentModel>> getBoxes() async {
    try {
      // Les boîtes sont généralement des équipements de catégorie "structure" ou "other"
      // On pourrait aussi ajouter un champ spécifique "isBox" dans le modèle
      final equipmentQuery = await _equipmentCollection
          .where('category', whereIn: [
            equipmentCategoryToString(EquipmentCategory.structure),
            equipmentCategoryToString(EquipmentCategory.other),
          ])
          .get();

      final boxes = <EquipmentModel>[];
      for (var doc in equipmentQuery.docs) {
        final equipment = EquipmentModel.fromMap(
          doc.data() as Map<String, dynamic>,
          doc.id,
        );
        // On pourrait ajouter un filtre supplémentaire ici si besoin
        boxes.add(equipment);
      }

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