import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:em2rp/models/event_model.dart';
import 'package:em2rp/models/equipment_model.dart';
import 'package:em2rp/models/container_model.dart';
import 'package:em2rp/providers/equipment_provider.dart';
import 'package:em2rp/providers/container_provider.dart';
import 'package:em2rp/providers/event_provider.dart';
import 'package:em2rp/providers/local_user_provider.dart';
import 'package:em2rp/services/data_service.dart';
import 'package:em2rp/services/api_service.dart';
import 'package:em2rp/services/api_service.dart';
import 'package:em2rp/views/widgets/equipment/equipment_checklist_item.dart' show EquipmentChecklistItem, ChecklistStep;
import 'package:em2rp/views/widgets/equipment/missing_equipment_dialog.dart';
import 'package:em2rp/utils/colors.dart';

/// Type d'étape de préparation
enum PreparationStep {
  preparation,    // Préparation dépôt
  loadingOutbound, // Chargement aller
  unloadingReturn, // Chargement retour (déchargement)
  return_,        // Retour dépôt
}

/// Page de préparation ou de retour d'un événement
class EventPreparationPage extends StatefulWidget {
  final EventModel initialEvent;

  const EventPreparationPage({
    super.key,
    required this.initialEvent,
  });

  @override
  State<EventPreparationPage> createState() => _EventPreparationPageState();
}

class _EventPreparationPageState extends State<EventPreparationPage> with SingleTickerProviderStateMixin {
  late AnimationController _animationController;
  late final DataService _dataService;

  Map<String, EquipmentModel> _equipmentCache = {};
  Map<String, ContainerModel> _containerCache = {};
  Map<String, int> _returnedQuantities = {};

  // État local des validations (non sauvegardé jusqu'à la validation finale)
  Map<String, bool> _localValidationState = {};

  bool _isLoading = true;
  bool _isValidating = false;
  bool _showSuccessAnimation = false;
  bool _loadSimultaneously = false; // Checkbox "charger en même temps"

  // Stockage de l'événement actuel
  late EventModel _currentEvent;

  // Détermine l'étape actuelle selon le statut de l'événement
  PreparationStep get _currentStep {
    final prep = _currentEvent.preparationStatus ?? PreparationStatus.notStarted;
    final loading = _currentEvent.loadingStatus ?? LoadingStatus.notStarted;
    final unloading = _currentEvent.unloadingStatus ?? UnloadingStatus.notStarted;
    final returnStatus = _currentEvent.returnStatus ?? ReturnStatus.notStarted;

    // Logique stricte : on avance étape par étape
    // 1. Préparation dépôt
    if (prep != PreparationStatus.completed) {
      return PreparationStep.preparation;
    }

    // 2. Chargement aller (après préparation complète)
    if (loading != LoadingStatus.completed) {
      return PreparationStep.loadingOutbound;
    }

    // 3. Chargement retour (après chargement aller complet)
    if (unloading != UnloadingStatus.completed) {
      return PreparationStep.unloadingReturn;
    }

    // 4. Retour dépôt (après déchargement complet)
    if (returnStatus != ReturnStatus.completed) {
      return PreparationStep.return_;
    }

    // Tout est terminé, par défaut on retourne à la préparation
    return PreparationStep.preparation;
  }

  @override
  void initState() {
    super.initState();
    _currentEvent = widget.initialEvent;
    _dataService = DataService(FirebaseFunctionsApiService());
    _animationController = AnimationController(
      vsync: this,
      duration: const Duration(milliseconds: 500),
    );

    // Vérification de sécurité et chargement après le premier frame
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (_isCurrentStepCompleted()) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('Cette étape est déjà terminée'),
            backgroundColor: Colors.orange,
          ),
        );
        Navigator.of(context).pop();
        return;
      }

      // Charger les équipements après le premier frame pour éviter setState pendant build
      _loadEquipmentAndContainers();
    });
  }

  /// Vérifie si l'étape actuelle est déjà complétée
  bool _isCurrentStepCompleted() {
    switch (_currentStep) {
      case PreparationStep.preparation:
        return (_currentEvent.preparationStatus ?? PreparationStatus.notStarted) == PreparationStatus.completed;
      case PreparationStep.loadingOutbound:
        return (_currentEvent.loadingStatus ?? LoadingStatus.notStarted) == LoadingStatus.completed;
      case PreparationStep.unloadingReturn:
        return (_currentEvent.unloadingStatus ?? UnloadingStatus.notStarted) == UnloadingStatus.completed;
      case PreparationStep.return_:
        return (_currentEvent.returnStatus ?? ReturnStatus.notStarted) == ReturnStatus.completed;
    }
  }

  @override
  void dispose() {
    _animationController.dispose();
    super.dispose();
  }

  Future<void> _loadEquipmentAndContainers() async {
    setState(() => _isLoading = true);

    try {
      final equipmentProvider = context.read<EquipmentProvider>();
      final containerProvider = context.read<ContainerProvider>();

      // S'assurer que les équipements sont chargés
      await equipmentProvider.ensureLoaded();
      await containerProvider.ensureLoaded();

      final equipment = await equipmentProvider.equipmentStream.first;
      final containers = await containerProvider.containersStream.first;

      for (var eq in _currentEvent.assignedEquipment) {
        final equipmentItem = equipment.firstWhere(
          (e) => e.id == eq.equipmentId,
          orElse: () => EquipmentModel(
            id: eq.equipmentId,
            name: 'Équipement inconnu',
            category: EquipmentCategory.other,
            status: EquipmentStatus.available,
            parentBoxIds: [],
            maintenanceIds: [],
            createdAt: DateTime.now(),
            updatedAt: DateTime.now(),
          ),
        );
        _equipmentCache[eq.equipmentId] = equipmentItem;

        // Initialiser l'état local de validation depuis l'événement
        switch (_currentStep) {
          case PreparationStep.preparation:
            _localValidationState[eq.equipmentId] = eq.isPrepared;
            break;
          case PreparationStep.loadingOutbound:
            _localValidationState[eq.equipmentId] = eq.isLoaded;
            break;
          case PreparationStep.unloadingReturn:
            _localValidationState[eq.equipmentId] = eq.isUnloaded;
            break;
          case PreparationStep.return_:
            _localValidationState[eq.equipmentId] = eq.isReturned;
            break;
        }

        if ((_currentStep == PreparationStep.return_ ||
             _currentStep == PreparationStep.unloadingReturn) &&
            equipmentItem.hasQuantity) {
          _returnedQuantities[eq.equipmentId] = eq.returnedQuantity ?? eq.quantity;
        }
      }

      for (var containerId in _currentEvent.assignedContainers) {
        final container = containers.firstWhere(
          (c) => c.id == containerId,
          orElse: () => ContainerModel(
            id: containerId,
            name: 'Conteneur inconnu',
            type: ContainerType.flightCase,
            status: EquipmentStatus.available,
            equipmentIds: [],
            updatedAt: DateTime.now(),
            createdAt: DateTime.now(),
          ),
        );
        _containerCache[containerId] = container;
      }
    } catch (e) {
      print('[EventPreparationPage] Error: $e');
    } finally {
      setState(() => _isLoading = false);
    }
  }

  /// Basculer l'état de validation d'un équipement (état local uniquement)
  void _toggleEquipmentValidation(String equipmentId) {
    setState(() {
      _localValidationState[equipmentId] = !(_localValidationState[equipmentId] ?? false);
    });
  }

  Future<void> _validateAll() async {
    setState(() => _isValidating = true);

    try {
      // Si "tout valider" est cliqué, marquer tout comme validé localement
      for (var equipmentId in _localValidationState.keys) {
        _localValidationState[equipmentId] = true;
      }

      // Préparer la liste des équipements avec leur nouvel état
      final updatedEquipment = _currentEvent.assignedEquipment.map((eq) {
        final isValidated = _localValidationState[eq.equipmentId] ?? false;

        switch (_currentStep) {
          case PreparationStep.preparation:
            if (_loadSimultaneously) {
              return eq.copyWith(isPrepared: isValidated, isLoaded: isValidated);
            }
            return eq.copyWith(isPrepared: isValidated);

          case PreparationStep.loadingOutbound:
            return eq.copyWith(isLoaded: isValidated);

          case PreparationStep.unloadingReturn:
            if (_loadSimultaneously) {
              final returnedQty = _returnedQuantities[eq.equipmentId] ?? eq.quantity;
              return eq.copyWith(isUnloaded: isValidated, isReturned: isValidated, returnedQuantity: returnedQty);
            }
            return eq.copyWith(isUnloaded: isValidated);

          case PreparationStep.return_:
            final returnedQty = _returnedQuantities[eq.equipmentId] ?? eq.quantity;
            return eq.copyWith(isReturned: isValidated, returnedQuantity: returnedQty);
        }
      }).toList();

      // Mettre à jour Firestore selon l'étape
      final updateData = <String, dynamic>{
        'assignedEquipment': updatedEquipment.map((e) => e.toMap()).toList(),
      };

      // Ajouter les statuts selon l'étape et la checkbox
      switch (_currentStep) {
        case PreparationStep.preparation:
          updateData['preparationStatus'] = preparationStatusToString(PreparationStatus.completed);
          if (_loadSimultaneously) {
            updateData['loadingStatus'] = loadingStatusToString(LoadingStatus.completed);
          }
          break;

        case PreparationStep.loadingOutbound:
          updateData['loadingStatus'] = loadingStatusToString(LoadingStatus.completed);
          break;

        case PreparationStep.unloadingReturn:
          updateData['unloadingStatus'] = unloadingStatusToString(UnloadingStatus.completed);
          if (_loadSimultaneously) {
            updateData['returnStatus'] = returnStatusToString(ReturnStatus.completed);
          }
          break;

        case PreparationStep.return_:
          updateData['returnStatus'] = returnStatusToString(ReturnStatus.completed);
          break;
      }

      // Sauvegarder dans Firestore via l'API
      await _dataService.updateEventEquipment(
        eventId: _currentEvent.id,
        assignedEquipment: updatedEquipment.map((e) => e.toMap()).toList(),
        preparationStatus: updateData['preparationStatus'],
        loadingStatus: updateData['loadingStatus'],
        unloadingStatus: updateData['unloadingStatus'],
        returnStatus: updateData['returnStatus'],
      );

      // Mettre à jour les statuts des équipements si nécessaire
      if (_currentStep == PreparationStep.preparation ||
          (_currentStep == PreparationStep.unloadingReturn && _loadSimultaneously)) {
        await _updateEquipmentStatuses(updatedEquipment);
      }

      // Recharger l'événement depuis le provider
      final eventProvider = context.read<EventProvider>();
      // Recharger la liste des événements pour rafraîchir les données
      final userId = context.read<LocalUserProvider>().uid;
      if (userId != null) {
        await eventProvider.loadUserEvents(userId, canViewAllEvents: true);
      }

      setState(() => _showSuccessAnimation = true);
      _animationController.forward();

      await Future.delayed(const Duration(milliseconds: 500));

      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text(_getSuccessMessage()),
            backgroundColor: Colors.green,
          ),
        );

        await Future.delayed(const Duration(seconds: 2));
        Navigator.of(context).pop(true);
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('Erreur : $e'),
            backgroundColor: Colors.red,
          ),
        );
      }
    } finally {
      if (mounted) setState(() => _isValidating = false);
    }
  }

  Future<void> _updateEquipmentStatuses(List<EventEquipment> equipment) async {
    for (var eq in equipment) {
      try {
        final equipmentData = _equipmentCache[eq.equipmentId];
        if (equipmentData == null) continue;

        // Déterminer le nouveau statut
        EquipmentStatus newStatus;
        if (eq.isReturned) {
          newStatus = EquipmentStatus.available;
        } else if (eq.isPrepared || eq.isLoaded) {
          newStatus = EquipmentStatus.inUse;
        } else {
          continue; // Pas de changement
        }

        // Ne mettre à jour que les équipements non quantifiables
        if (!equipmentData.hasQuantity) {
          await _dataService.updateEquipmentStatusOnly(
            equipmentId: eq.equipmentId,
            status: equipmentStatusToString(newStatus),
          );
        }

        // Gérer les stocks pour les consommables
        if (equipmentData.hasQuantity && eq.isReturned && eq.returnedQuantity != null) {
          final currentAvailable = equipmentData.availableQuantity ?? 0;
          await _dataService.updateEquipmentStatusOnly(
            equipmentId: eq.equipmentId,
            availableQuantity: currentAvailable + eq.returnedQuantity!,
          );
        }
      } catch (e) {
        // Erreur silencieuse pour ne pas bloquer le processus
      }
    }
  }

  String _getSuccessMessage() {
    switch (_currentStep) {
      case PreparationStep.preparation:
        return _loadSimultaneously
            ? 'Préparation dépôt et chargement aller validés !'
            : 'Préparation dépôt validée !';
      case PreparationStep.loadingOutbound:
        return 'Chargement aller validé !';
      case PreparationStep.unloadingReturn:
        return _loadSimultaneously
            ? 'Chargement retour et retour dépôt validés !'
            : 'Chargement retour validé !';
      case PreparationStep.return_:
        return 'Retour dépôt validé !';
    }
  }

  String _getStepTitle() {
    switch (_currentStep) {
      case PreparationStep.preparation:
        return 'Préparation dépôt';
      case PreparationStep.loadingOutbound:
        return 'Chargement aller';
      case PreparationStep.unloadingReturn:
        return 'Chargement retour';
      case PreparationStep.return_:
        return 'Retour dépôt';
    }
  }

  String _getValidateAllButtonText() {
    if (_loadSimultaneously) {
      return _currentStep == PreparationStep.preparation
          ? 'Tout confirmer comme préparé et chargé'
          : 'Tout confirmer comme déchargé et retourné';
    }

    switch (_currentStep) {
      case PreparationStep.preparation:
        return 'Tout confirmer comme préparé';
      case PreparationStep.loadingOutbound:
        return 'Tout confirmer comme chargé';
      case PreparationStep.unloadingReturn:
        return 'Tout confirmer comme déchargé';
      case PreparationStep.return_:
        return 'Tout confirmer comme retourné';
    }
  }

  bool _isStepCompleted() {
    return _currentEvent.assignedEquipment.every((eq) {
      return _localValidationState[eq.equipmentId] ?? false;
    });
  }

  double _getProgress() {
    if (_currentEvent.assignedEquipment.isEmpty) return 0;
    return _getValidatedCount() / _currentEvent.assignedEquipment.length;
  }

  int _getValidatedCount() {
    return _currentEvent.assignedEquipment.where((eq) {
      return _localValidationState[eq.equipmentId] ?? false;
    }).length;
  }

  ChecklistStep _getChecklistStep() {
    switch (_currentStep) {
      case PreparationStep.preparation:
        return ChecklistStep.preparation;
      case PreparationStep.loadingOutbound:
        return ChecklistStep.loading;
      case PreparationStep.unloadingReturn:
        return ChecklistStep.unloading;
      case PreparationStep.return_:
        return ChecklistStep.return_;
    }
  }

  Future<void> _confirm() async {
    // Vérifier s'il y a des équipements manquants (non cochés localement)
    final missingEquipmentIds = _currentEvent.assignedEquipment
        .where((eq) => !(_localValidationState[eq.equipmentId] ?? false))
        .map((eq) => eq.equipmentId)
        .toList();

    if (missingEquipmentIds.isEmpty) {
      // Tout est validé, confirmer directement
      await _validateAll();
    } else {
      // Afficher le dialog des manquants
      final missingEquipmentModels = missingEquipmentIds
          .map((id) => _equipmentCache[id])
          .whereType<EquipmentModel>()
          .toList();

      final missingEventEquipment = _currentEvent.assignedEquipment
          .where((eq) => missingEquipmentIds.contains(eq.equipmentId))
          .toList();

      final action = await showDialog<String>(
        context: context,
        builder: (context) => MissingEquipmentDialog(
          missingEquipment: missingEquipmentModels,
          eventEquipment: missingEventEquipment,
          isReturnMode: _currentStep == PreparationStep.return_ ||
                        _currentStep == PreparationStep.unloadingReturn,
        ),
      );

      if (action == 'confirm_anyway') {
        // Confirmer malgré les manquants
        await _validateAll();
      } else if (action == 'mark_as_validated') {
        // Marquer les manquants comme validés localement
        for (var equipmentId in missingEquipmentIds) {
          _localValidationState[equipmentId] = true;
        }
        setState(() {});
        // Puis confirmer
        await _validateAll();
      }
      // Si 'return_to_list', ne rien faire
    }
  }

  @override
  Widget build(BuildContext context) {
    final allValidated = _isStepCompleted();
    final stepTitle = _getStepTitle();

    return Scaffold(
      appBar: AppBar(
        title: Text(stepTitle),
        backgroundColor: AppColors.bleuFonce,
      ),
      body: Stack(
        children: [
          _isLoading
              ? const Center(child: CircularProgressIndicator())
              : Column(
                  children: [
                    Container(
                      padding: const EdgeInsets.all(16),
                      color: Colors.grey.shade100,
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.stretch,
                        children: [
                          Text(
                            _currentEvent.name,
                            style: const TextStyle(
                              fontSize: 20,
                              fontWeight: FontWeight.bold,
                            ),
                          ),
                          const SizedBox(height: 8),
                          Row(
                            children: [
                              Expanded(
                                child: LinearProgressIndicator(
                                  value: _getProgress(),
                                  backgroundColor: Colors.grey.shade300,
                                  valueColor: AlwaysStoppedAnimation<Color>(
                                    allValidated ? Colors.green : AppColors.bleuFonce,
                                  ),
                                ),
                              ),
                              const SizedBox(width: 12),
                              Text(
                                '${_getValidatedCount()}/${_currentEvent.assignedEquipment.length}',
                                style: const TextStyle(
                                  fontWeight: FontWeight.bold,
                                  fontSize: 16,
                                ),
                              ),
                            ],
                          ),
                          const SizedBox(height: 12),

                          // Checkbox "charger en même temps" (uniquement pour préparation ou chargement retour)
                          if (_currentStep == PreparationStep.preparation ||
                              _currentStep == PreparationStep.unloadingReturn)
                            CheckboxListTile(
                              value: _loadSimultaneously,
                              onChanged: (value) {
                                setState(() {
                                  _loadSimultaneously = value ?? false;
                                });
                              },
                              title: Text(
                                _currentStep == PreparationStep.preparation
                                    ? 'Charger en même temps (chargement aller)'
                                    : 'Confirmer le retour en même temps (retour dépôt)',
                                style: const TextStyle(
                                  fontSize: 14,
                                  fontWeight: FontWeight.w500,
                                ),
                              ),
                              dense: true,
                              contentPadding: EdgeInsets.zero,
                            ),

                          const SizedBox(height: 8),
                          ElevatedButton.icon(
                            onPressed: allValidated ? null : _validateAll,
                            icon: const Icon(Icons.check_circle_outline),
                            label: Text(
                              allValidated
                                  ? 'Tout est validé !'
                                  : _getValidateAllButtonText(),
                            ),
                            style: ElevatedButton.styleFrom(
                              backgroundColor: allValidated ? Colors.green : AppColors.bleuFonce,
                              padding: const EdgeInsets.symmetric(vertical: 12),
                            ),
                          ),
                        ],
                      ),
                    ),
                    Expanded(
                      child: ListView.builder(
                        padding: const EdgeInsets.all(16),
                        itemCount: _currentEvent.assignedEquipment.length,
                        itemBuilder: (context, index) {
                          final eventEquipment = _currentEvent.assignedEquipment[index];
                          final equipment = _equipmentCache[eventEquipment.equipmentId];

                          if (equipment == null) {
                            return const SizedBox.shrink();
                          }

                          return EquipmentChecklistItem(
                            equipment: equipment,
                            eventEquipment: eventEquipment,
                            step: _getChecklistStep(),
                            isValidated: _localValidationState[equipment.id] ?? false,
                            onToggle: () => _toggleEquipmentValidation(equipment.id),
                            onReturnedQuantityChanged: _currentStep == PreparationStep.return_ && equipment.hasQuantity
                                ? (qty) {
                                    setState(() {
                                      _returnedQuantities[equipment.id] = qty;
                                    });
                                  }
                                : null,
                          );
                        },
                      ),
                    ),
                  ],
                ),
          if (_showSuccessAnimation)
            Center(
              child: ScaleTransition(
                scale: _animationController,
                child: Container(
                  padding: const EdgeInsets.all(32),
                  decoration: const BoxDecoration(
                    color: Colors.green,
                    shape: BoxShape.circle,
                  ),
                  child: const Icon(
                    Icons.check,
                    size: 64,
                    color: Colors.white,
                  ),
                ),
              ),
            ),
        ],
      ),
      bottomNavigationBar: Container(
        padding: const EdgeInsets.all(16),
        decoration: BoxDecoration(
          color: Colors.white,
          boxShadow: [
            BoxShadow(
              color: Colors.black.withValues(alpha: 0.1),
              blurRadius: 4,
              offset: const Offset(0, -2),
            ),
          ],
        ),
        child: ElevatedButton(
          onPressed: _isValidating ? null : _confirm,
          style: ElevatedButton.styleFrom(
            backgroundColor: allValidated ? Colors.green : AppColors.rouge,
            padding: const EdgeInsets.symmetric(vertical: 16),
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(8),
            ),
          ),
          child: _isValidating
              ? const SizedBox(
                  height: 20,
                  width: 20,
                  child: CircularProgressIndicator(
                    strokeWidth: 2,
                    valueColor: AlwaysStoppedAnimation<Color>(Colors.white),
                  ),
                )
              : Text(
                  'Confirmer ${_getStepTitle().toLowerCase()}',
                  style: const TextStyle(
                    fontSize: 18,
                    fontWeight: FontWeight.bold,
                  ),
                ),
        ),
      ),
    );
  }
}