import 'dart:async';

import 'package:equatable/equatable.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:tunas/repositories/metadata/models/budget.dart';
import 'package:tunas/repositories/metadata/metadata_repository.dart';

part 'budget_event.dart';
part 'budget_state.dart';

class BudgetBloc extends Bloc<BudgetEvent, BudgetState> {
  final MetadataRepository _metadataRepository;

  BudgetBloc({required MetadataRepository metadataRepository}) : _metadataRepository = metadataRepository, super(const BudgetState())  {
    on<BudgetsLoad>(_onBudgetsLoad);
    on<BudgetAdd>(_onBudgetAdd);
    on<BudgetRemove>(_onBudgetRemove);
    on<BudgetSetValue>(_onBudgetSetValue);
    on<BudgetCompareNext>(_onBudgetCompareNext);
    on<BudgetComparePrevious>(_onBudgetComparePrevious);

    _metadataRepository
      .getBudgetsStream()
      .listen((budgets) => add(BudgetsLoad(budgets)));
  }

  _onBudgetsLoad(
    BudgetsLoad event, Emitter<BudgetState> emit
  ) {
    emit(state.copyWith(
      budgets: event.budgets,
    ));
  }

  FutureOr<void> _onBudgetAdd(BudgetAdd event, Emitter<BudgetState> emit) async {
    Budget budget = Budget(
      label: event.label,
    );

    emit(_computeState(await _saveBudget(budget)));
  }

  FutureOr<void> _onBudgetRemove(BudgetRemove event, Emitter<BudgetState> emit) async {
    List<Budget> budgets = _metadataRepository.getBudgets();
    Budget budgetToRemove = event.budget;

    budgets.removeWhere((budget) => budget.label == budgetToRemove.label);
    emit(_computeState(await _metadataRepository.saveBudgets(budgets)));
  }

  FutureOr<void> _onBudgetSetValue(BudgetSetValue event, Emitter<BudgetState> emit) async {
    Budget budgetToUpdate = event.budget;

    if (state.remainingBudget - (event.value - budgetToUpdate.value) < 0) {
      return;
    }

    // if (state.remainingBudget - event.value < 0 && state.remainingBudget < 10) {
    //   budgetToUpdate.value = 
    // } else {
    //   budgetToUpdate.value = event.value;
    // }
    budgetToUpdate.value = event.value;

    emit(_computeState(await _saveBudget(budgetToUpdate)));
  }

  FutureOr<void> _onBudgetCompareNext(BudgetCompareNext event, Emitter<BudgetState> emit) {
  }

  FutureOr<void> _onBudgetComparePrevious(BudgetComparePrevious event, Emitter<BudgetState> emit) {
  }

  Future<List<Budget>> _saveBudget(Budget budgetToSave) async {
    List<Budget> budgets = _metadataRepository.getBudgets();

    try {
      Budget budgetFound = budgets.firstWhere((category) => category.label == budgetToSave.label);
      budgetFound.value = budgetToSave.value;
    } catch (e) {
      if (budgets.isEmpty) {
        budgets = [budgetToSave];
      } else {
        budgets.add(budgetToSave);
      }
    }

    // _metadataRepository.saveBudgets(budgets);
    return budgets;
  }

  BudgetState _computeState(List<Budget> budgets) {
    return state.copyWith(
      budgets: budgets,
      remainingBudget: state.initialBudget - budgets.map((budget) => budget.value).reduce((value, element) => value + element),
    );
  }
}