import 'dart:math';
import 'package:flutter_bloc/flutter_bloc.dart';
import '../../models/models.dart';
import 'add_book_event.dart';
import 'add_book_state.dart';

class AddBookBloc extends Bloc<AddBookEvent, AddBookState> {
  final void Function(Book book) onAddBook;
  final void Function(Book book) onUpdateBook;

  AddBookBloc({required this.onAddBook, required this.onUpdateBook})
    : super(const AddBookState()) {
    on<InitializeForm>(_onInitializeForm);
    on<UpdateTitle>(_onUpdateTitle);
    on<UpdateAuthor>(_onUpdateAuthor);
    on<UpdateAnnotation>(_onUpdateAnnotation);
    on<UpdateGenre>(_onUpdateGenre);
    on<ApplyScannedBook>(_onApplyScannedBook);
    on<SaveBook>(_onSaveBook);
  }

  void _onInitializeForm(InitializeForm event, Emitter<AddBookState> emit) {
    final source = event.editBook ?? event.prefilledData;
    if (source != null) {
      emit(
        AddBookState(
          title: source.title,
          author: source.author,
          annotation: source.annotation,
          genre: source.genre.isNotEmpty ? source.genre : 'fiction',
          editBook: event.editBook,
        ),
      );
    } else if (event.editBook != null) {
      emit(state.copyWith(editBook: event.editBook));
    }
  }

  void _onUpdateTitle(UpdateTitle event, Emitter<AddBookState> emit) {
    emit(state.copyWith(title: event.title));
  }

  void _onUpdateAuthor(UpdateAuthor event, Emitter<AddBookState> emit) {
    emit(state.copyWith(author: event.author));
  }

  void _onUpdateAnnotation(UpdateAnnotation event, Emitter<AddBookState> emit) {
    emit(state.copyWith(annotation: event.annotation));
  }

  void _onUpdateGenre(UpdateGenre event, Emitter<AddBookState> emit) {
    emit(state.copyWith(genre: event.genre));
  }

  void _onApplyScannedBook(ApplyScannedBook event, Emitter<AddBookState> emit) {
    final scanned = event.scannedBook;
    emit(
      state.copyWith(
        title: scanned.title,
        author: scanned.author,
        annotation: scanned.annotation,
        genre: scanned.genre.isNotEmpty ? scanned.genre : 'fiction',
      ),
    );
  }

  void _onSaveBook(SaveBook event, Emitter<AddBookState> emit) {
    final existing = state.editBook;
    final isEditing = existing != null;

    final Book book = (
      id: isEditing ? existing.id : '${Random().nextInt(100000)}',
      title: state.title,
      author: state.author,
      genre: state.genre,
      annotation: state.annotation,
      coverUrl: isEditing
          ? existing.coverUrl
          : 'https://picsum.photos/seed/newbook/400/600',
      pages: isEditing ? existing.pages : 0,
      language: isEditing ? existing.language : 'Russian',
      publishedYear: isEditing ? existing.publishedYear : DateTime.now().year,
      rating: isEditing ? existing.rating : 5.0,
      status: isEditing ? existing.status : 'want_to_read',
      progress: isEditing ? existing.progress : null,
      isFavorite: isEditing ? existing.isFavorite : false,
    );

    if (isEditing) {
      onUpdateBook(book);
    } else {
      onAddBook(book);
    }

    emit(state.copyWith(isSaved: true));
  }
}