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/operations_repository.dart';
import 'package:flux/features/operations/models/operation_file_model.dart';
import 'package:flux/features/operations/models/operation_model.dart';
import 'package:get_it/get_it.dart';

part 'operation_files_events.dart';
part 'operation_files_state.dart';

class OperationFilesBloc
    extends Bloc<OperationFilesEvent, OperationFilesState> {
  final _repository = GetIt.I.get<OperationsRepository>();
  final String? operationId;

  OperationFilesBloc({this.operationId})
    : super(
        OperationFilesState(
          status: OperationFilesStatus.initial,
          operationId: operationId,
        ),
      ) {
    on<OperationsavedEvent>(_onOperationsaved);
    on<LoadOperationFilesEvent>(_onLoadOperationFiles);
    on<AddOperationFilesEvent>(_onAddOperationFiles);
    on<UploadOperationFilesEvent>(_onUploadOperationFiles);
    on<UploadMultipleOperationFilesEvent>(_onUploadMultipleOperationFiles);
    on<DeleteOperationFilesEvent>(_onDeleteOperationFiles);
    on<ToggleOperationFileSelectionEvent>(_onToggleOperationFileSelection);
    // Se il BLoC nasce con un ID, accendiamo subito lo stream!
    if (operationId != null) {
      add(LoadOperationFilesEvent(operationId: operationId));
    }
  }

  FutureOr<void> _onOperationsaved(
    OperationsavedEvent event,
    Emitter<OperationFilesState> 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(
        operationId: event.operationId,
        localFiles: [], // <-- LA MAGIA ANTI-DUPLICATI
      ),
    );

    // Lanciamo il caricamento
    add(LoadOperationFilesEvent(operationId: event.operationId));
  }

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

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

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

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

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

  FutureOr<void> _onUploadOperationFiles(
    UploadOperationFilesEvent event,
    Emitter<OperationFilesState> 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: OperationFilesStatus.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.uploadAndRegisterOperationFile(
            operationId: state.operationId!,
            pickedFile: file,
          );
        }
      }
      emit(state.copyWith(status: OperationFilesStatus.success));
    } catch (e) {
      emit(
        state.copyWith(
          status: OperationFilesStatus.failure,
          error: e.toString(),
        ),
      );
    }
  }

  FutureOr<void> _onUploadMultipleOperationFiles(
    UploadMultipleOperationFilesEvent event,
    Emitter<OperationFilesState> emit,
  ) async {
    if (event.files.isEmpty) {
      emit(
        state.copyWith(
          status: OperationFilesStatus.failure,
          error: "Nessun file selezionato",
        ),
      );
      return;
    }
    emit(state.copyWith(status: OperationFilesStatus.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.uploadAndRegisterOperationFile(
            operationId: state.operationId!,
            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: OperationFilesStatus.success));
    } catch (e) {
      // Se anche un solo file fallisce, catturiamo l'errore
      emit(
        state.copyWith(
          status: OperationFilesStatus.failure,
          error: "Errore durante l'upload multiplo: $e",
        ),
      );
    }
  }

  FutureOr<void> _onDeleteOperationFiles(
    DeleteOperationFilesEvent event,
    Emitter<OperationFilesState> emit,
  ) async {
    emit(state.copyWith(status: OperationFilesStatus.loading));
    try {
      await _repository.deleteOperationFiles(state.selectedFiles);
      emit(
        state.copyWith(status: OperationFilesStatus.success, selectedFiles: []),
      );
    } catch (e) {
      emit(
        state.copyWith(
          status: OperationFilesStatus.failure,
          error: e.toString(),
        ),
      );
    }
  }

  FutureOr<void> _onToggleOperationFileSelection(
    ToggleOperationFileSelectionEvent event,
    Emitter<OperationFilesState> emit,
  ) {
    List<OperationFileModel> selectedFiles = List.from(state.selectedFiles);
    if (selectedFiles.contains(event.file)) {
      selectedFiles.remove(event.file);
    } else {
      selectedFiles.add(event.file);
    }
    emit(state.copyWith(selectedFiles: selectedFiles));
  }
}