import 'dart:async';
import 'dart:io';

import 'package:file_picker/file_picker.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:equatable/equatable.dart';
import 'package:flux/core/utils/extensions.dart';
import 'package:flux/features/operations/data/services_repository.dart';
import 'package:flux/features/operations/models/service_file_model.dart';
import 'package:flux/features/operations/models/service_model.dart';
import 'package:get_it/get_it.dart';

part 'service_files_events.dart';
part 'service_files_state.dart';

class ServiceFilesBloc extends Bloc<ServiceFilesEvent, ServiceFilesState> {
  final _repository = GetIt.I.get<ServicesRepository>();
  final String? serviceId;

  ServiceFilesBloc({this.serviceId})
    : super(
        ServiceFilesState(
          status: ServiceFilesStatus.initial,
          serviceId: serviceId,
        ),
      ) {
    on<ServiceSavedEvent>(_onServiceSaved);
    on<LoadServiceFilesEvent>(_onLoadServiceFiles);
    on<AddServiceFilesEvent>(_onAddServiceFiles);
    on<UploadServiceFilesEvent>(_onUploadServiceFiles);
    on<UploadMultipleServiceFilesEvent>(_onUploadMultipleServiceFiles);
    on<DeleteServiceFilesEvent>(_onDeleteServiceFiles);
    on<ToggleServiceFileSelectionEvent>(_onToggleServiceFileSelection);
    // Se il BLoC nasce con un ID, accendiamo subito lo stream!
    if (serviceId != null) {
      add(LoadServiceFilesEvent(serviceId: serviceId));
    }
  }

  FutureOr<void> _onServiceSaved(
    ServiceSavedEvent event,
    Emitter<ServiceFilesState> emit,
  ) {
    // 1. Aggiorniamo l'ID nello stato
    // 2. PIALLIAMO i file locali: ormai sono partiti per Supabase!
    // Così la UI si pulisce all'istante e aspetta quelli remoti.
    emit(
      state.copyWith(
        serviceId: event.serviceId,
        localFiles: [], // <-- LA MAGIA ANTI-DUPLICATI
      ),
    );

    // Lanciamo il caricamento
    add(LoadServiceFilesEvent(serviceId: event.serviceId));
  }

  FutureOr<void> _onLoadServiceFiles(
    LoadServiceFilesEvent event,
    Emitter<ServiceFilesState> emit,
  ) async {
    // Usiamo l'ID dell'evento, e se non c'è usiamo quello dello stato
    final currentId = event.serviceId ?? state.serviceId;

    if (currentId != null) {
      emit(state.copyWith(status: ServiceFilesStatus.loading));

      await emit.forEach(
        _repository.getServiceFilesStream(
          currentId,
        ), // <-- Usiamo l'ID corretto!
        onData: (data) => state.copyWith(
          status: ServiceFilesStatus.success,
          remoteFiles: data,
        ),
        onError: (error, stackTrace) => state.copyWith(
          status: ServiceFilesStatus.failure,
          error: error.toString(),
        ),
      );
    }
  }

  void _onAddServiceFiles(
    AddServiceFilesEvent event,
    Emitter<ServiceFilesState> emit,
  ) async {
    final currentId = state.serviceId;
    // BIVIO 1: PRATICA NUOVA (Nessun ID)
    if (currentId == null) {
      // Mettiamo i file nel "parcheggio" locale dello State
      final newLocalFiles = event.files.map((file) {
        return ServiceFileModel(
          id: null,
          serviceId: serviceId ?? '',
          name: file.name.fileNameWithoutExtension(),
          extension: file.name.fileExtension(),
          storagePath: '',
          fileSize: file.size,
          localBytes: file.bytes,
        );
      }).toList();
      final List<ServiceFileModel> updatedLocalFiles = [
        ...state.localFiles,
        ...newLocalFiles,
      ];
      emit(
        state.copyWith(
          localFiles: updatedLocalFiles,
          status: ServiceFilesStatus.success,
        ),
      );
      return;
    }

    // BIVIO 2: PRATICA ESISTENTE (Abbiamo l'ID)
    emit(state.copyWith(status: ServiceFilesStatus.uploading));
    try {
      // Logica identica a quella che abbiamo fatto per i clienti
      for (var file in event.files) {
        await _repository.uploadAndRegisterServiceFile(
          serviceId: serviceId!,
          pickedFile: file,
        );
      }
      emit(state.copyWith(status: ServiceFilesStatus.success));
    } catch (e) {
      emit(
        state.copyWith(status: ServiceFilesStatus.failure, error: e.toString()),
      );
    }
  }

  FutureOr<void> _onUploadServiceFiles(
    UploadServiceFilesEvent event,
    Emitter<ServiceFilesState> emit,
  ) async {
    if (event.pickedFiles == null && event.photos == null) return;
    if (event.pickedFiles!.isEmpty && event.photos!.isEmpty) return;

    // BIVIO 2: PRATICA ESISTENTE (Abbiamo l'ID
    emit(state.copyWith(status: ServiceFilesStatus.uploading));
    try {
      // Logica identica a quella che abbiamo fatto per i clienti
      if (event.pickedFiles != null && event.pickedFiles!.isNotEmpty) {
        for (var file in event.pickedFiles!) {
          await _repository.uploadAndRegisterServiceFile(
            serviceId: state.serviceId!,
            pickedFile: file,
          );
        }
      }
      emit(state.copyWith(status: ServiceFilesStatus.success));
    } catch (e) {
      emit(
        state.copyWith(status: ServiceFilesStatus.failure, error: e.toString()),
      );
    }
  }

  FutureOr<void> _onUploadMultipleServiceFiles(
    UploadMultipleServiceFilesEvent event,
    Emitter<ServiceFilesState> emit,
  ) async {
    if (event.files.isEmpty) {
      emit(
        state.copyWith(
          status: ServiceFilesStatus.failure,
          error: "Nessun file selezionato",
        ),
      );
      return;
    }
    emit(state.copyWith(status: ServiceFilesStatus.uploading, error: null));
    try {
      // 2. Creiamo una lista di "Promesse" (Futures) per il repository
      final List<Future<void>> uploadTasks = [];
      for (var file in event.files) {
        // Aggiungiamo il task alla lista, ma NON usiamo await qui dentro!
        uploadTasks.add(
          _repository.uploadAndRegisterServiceFile(
            serviceId: state.serviceId!,
            pickedFile: file,
          ),
        );
      }
      // 3. ESECUZIONE PARALLELA!
      // Aspettiamo che tutti i file siano caricati contemporaneamente.
      await Future.wait(uploadTasks);
      // 4. GRAN FINALE: Tutto caricato, emettiamo il success!
      emit(state.copyWith(status: ServiceFilesStatus.success));
    } catch (e) {
      // Se anche un solo file fallisce, catturiamo l'errore
      emit(
        state.copyWith(
          status: ServiceFilesStatus.failure,
          error: "Errore durante l'upload multiplo: $e",
        ),
      );
    }
  }

  FutureOr<void> _onDeleteServiceFiles(
    DeleteServiceFilesEvent event,
    Emitter<ServiceFilesState> emit,
  ) async {
    emit(state.copyWith(status: ServiceFilesStatus.loading));
    try {
      await _repository.deleteServiceFiles(state.selectedFiles);
      emit(
        state.copyWith(status: ServiceFilesStatus.success, selectedFiles: []),
      );
    } catch (e) {
      emit(
        state.copyWith(status: ServiceFilesStatus.failure, error: e.toString()),
      );
    }
  }

  FutureOr<void> _onToggleServiceFileSelection(
    ToggleServiceFileSelectionEvent event,
    Emitter<ServiceFilesState> emit,
  ) {
    List<ServiceFileModel> selectedFiles = List.from(state.selectedFiles);
    if (selectedFiles.contains(event.file)) {
      selectedFiles.remove(event.file);
    } else {
      selectedFiles.add(event.file);
    }
    emit(state.copyWith(selectedFiles: selectedFiles));
  }
}