import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:kalodings/storage/storage.dart';
import 'package:uuid/uuid.dart';

class FoodEntryBloc extends Bloc<FoodEvent, FoodEntryState> {
  final FoodStorage storage;

  FoodEntryBloc(super.initialState, {required this.storage}) {
    on<FoodEntryEvent>(addFoodEntry);
    on<FoodDeletionEvent>(deleteFood);
    on<PageChangedEvent>(updateEntries);
    on<DailyKcalLimitUpdated>(persistDailyLimit);
  }

  void addFoodEntry(FoodEntryEvent event, Emitter<FoodEntryState> emit) async {
    FoodEntryState newState = FoodEntryState.from(state);
    newState.addEntry(event.entry);

    await storage.writeEntriesForDate(event.date, newState.foodEntries);

    emit(newState);
  }

  void deleteFood(FoodDeletionEvent event, Emitter<FoodEntryState> emit) async {
    state.foodEntries.removeWhere((entry) => entry.id == event.entryID);

    await storage.writeEntriesForDate(event.date, state.foodEntries);

    emit(FoodEntryState.from(state));
  }

  void updateEntries(
      PageChangedEvent event, Emitter<FoodEntryState> emit) async {
    var entries = await storage.getEntriesForDate(event.changedToDate);
    var limit = await storage.readLimit();
    var newState = FoodEntryState(foodEntries: entries, kcalLimit: limit);
    emit(newState);
  }

  void persistDailyLimit(
      DailyKcalLimitUpdated event, Emitter<FoodEntryState> emit) async {
    await storage.updateLimit(event.kcal);
    emit(FoodEntryState(foodEntries: state.foodEntries, kcalLimit: event.kcal));
  }

  void getDailyLimit(
      DailyKcalLimitUpdated event, Emitter<FoodEntryState> emit) async {}
}

class FoodEvent {}

class FoodEntryEvent extends FoodEvent {
  final FoodEntry entry;
  final DateTime date;

  FoodEntryEvent({required this.entry, required this.date});
}

class FoodDeletionEvent extends FoodEvent {
  final String entryID;
  final DateTime date;

  FoodDeletionEvent({required this.entryID, required this.date});
}

class PageChangedEvent extends FoodEvent {
  final DateTime changedToDate;

  PageChangedEvent({required this.changedToDate});
}

class DailyKcalLimitUpdated extends FoodEvent {
  final double kcal;
  DailyKcalLimitUpdated({required this.kcal});
}

class FoodEntryState {
  final List<FoodEntry> foodEntries;
  final double kcalLimit;

  FoodEntryState({required this.foodEntries, required this.kcalLimit});

  factory FoodEntryState.init() {
    return FoodEntryState(foodEntries: [], kcalLimit: 0);
  }

  static from(FoodEntryState state) {
    List<FoodEntry> newList = List.from(state.foodEntries);
    return FoodEntryState(foodEntries: newList, kcalLimit: state.kcalLimit);
  }

  void addEntry(FoodEntry entry) {
    foodEntries.add(entry);
  }
}

class FoodEntry {
  final String name;
  final double mass;
  final double kcalPerMass;
  final String id;

  FoodEntry({
    required this.name,
    required this.mass,
    required this.kcalPerMass,
  }) : id = const Uuid().v1();

  @override
  String toString() {
    return '$id,$name,$mass,$kcalPerMass';
  }
}