Seshat/lib/ui/add_page/view_model/add_view_model.dart

import 'dart:async';

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:mobile_scanner/mobile_scanner.dart';
import 'package:seshat/data/repositories/bal_repository.dart';
import 'package:seshat/data/repositories/book_instance_repository.dart';
import 'package:seshat/data/repositories/book_repository.dart';
import 'package:seshat/data/repositories/owner_repository.dart';
import 'package:seshat/domain/models/bal.dart';
import 'package:seshat/domain/models/book.dart';
import 'package:seshat/domain/models/book_instance.dart';
import 'package:seshat/domain/models/owner.dart';
import 'package:seshat/utils/command.dart';
import 'package:seshat/utils/result.dart';

class AddViewModel extends ChangeNotifier {
  AddViewModel({
    required OwnerRepository ownerRepository,
    required BookRepository bookRepository,
    required BookInstanceRepository bookInstanceRepository,
    required BalRepository balRepository,
  }) : _ownerRepository = ownerRepository,
       _bookRepository = bookRepository,
       _bookInstanceRepository = bookInstanceRepository,
       _balRepository = balRepository {
    load = Command0(_load)..execute();
  }

  final OwnerRepository _ownerRepository;
  final BookRepository _bookRepository;
  final BookInstanceRepository _bookInstanceRepository;
  final BalRepository _balRepository;

  /*
 * ====================
 * =====[ OWNERS ]=====
 * ====================
*/

  /// Owner currently selected in the ui
  Owner? _currentOwner;

  /// Owner currently selected in the ui
  Owner? get currentOwner => _currentOwner;
  set currentOwner(Owner? owner) {
    _currentOwner = owner;
    notifyListeners();
  }

  /// Owner of the current user
  Owner? _ownerOfUser;

  /// Owner of the current user
  Owner? get ownerOfUser => _ownerOfUser;

  /// All the [Owner]
  List<Owner> _owners = [];

  /// All the [Owner]
  List<Owner>? get owners => _owners;

  /// Adds an owner from it's [firstName], [lastName] and [contact]
  Future<Result<Owner>> addOwner(
    String firstName,
    String lastName,
    String contact,
  ) async {
    final result = await _ownerRepository.addOwner(
      firstName,
      lastName,
      contact,
    );

    switch (result) {
      case Ok():
        final secondResult = await _ownerRepository.getOwners();

        switch (secondResult) {
          case Ok():
            _owners = secondResult.value;
            _currentOwner = result.value;
            notifyListeners();
            return Result.ok(result.value);
          case Error():
            return Result.error(secondResult.error);
        }
      case Error():
        return Result.error(result.error);
    }
  }

  /*
 * =================
 * =====[ BAL ]=====
 * =================
*/

  /// Ongoing [Bal]
  Bal? _ongoingBal;

  /// Ongoing [Bal]
  Bal? get ongoingBal => _ongoingBal;

  /*
 * ===================
 * =====[ PRICE ]=====
 * ===================
*/

  /// Wether to ask for a price
  bool _askPrice = true;

  /// Wether to ask for a price
  bool get askPrice => _askPrice;
  set askPrice(bool newValue) {
    _askPrice = newValue;
    notifyListeners();
  }

  /*
 * =================================
 * =====[ BOOKS AND INSTANCES ]=====
 * =================================
*/

  /// Retrieves the book associated with an ean through a [barcode]
  Future<Result<Book>> scanBook(String ean) async {
    var result = await _bookRepository.getBookByEAN(ean);
    return result;
  }

  /// Creates a new Book Instance from its [book], [owner], [bal] and [price]
  Future<Result<BookInstance>> sendNewBookInstance(
    Book book,
    Owner owner,
    Bal bal,
    double price,
  ) async {
    return await _bookInstanceRepository.sendNewBookInstance(
      book,
      owner,
      bal,
      price,
    );
  }

  /*
 * =================================
 * =====[ COMMAND AND LOADING ]=====
 * =================================
*/

  /// Command to load the view model
  late final Command0 load;
  bool isLoaded = false;

  /// Manages the loaders
  Future<Result<void>> _load() async {
    final result1 = await _loadOwners();
    switch (result1) {
      case Error():
        return result1;
      default:
        break;
    }
    final result2 = await _loadBal();
    switch (result2) {
      case Ok():
        isLoaded = true;
        break;
      default:
        break;
    }
    notifyListeners();
    return result2;
  }

  /// Loads all necessary data about [Bal]s
  Future<Result<void>> _loadBal() async {
    final result = await _balRepository.getBals();
    switch (result) {
      case Ok():
        _ongoingBal = result.value
            .where((bal) => bal.state == BalState.ongoing)
            .firstOrNull;
        break;
      case Error():
        break;
    }

    return result;
  }

  /// Loads all the necessary data about [Owner]s
  Future<Result<void>> _loadOwners() async {
    final result = await _ownerRepository.getOwners();
    switch (result) {
      case Ok():
        _owners = result.value
          ..sort(
            (a, b) => "${a.firstName} ${a.lastName}".compareTo(
              "${b.firstName} ${b.lastName}",
            ),
          );
      case Error():
        return result;
    }

    final result2 = await _ownerRepository.ownerOfUser;
    switch (result2) {
      case Ok():
        _ownerOfUser = result2.value;
        break;
      default:
    }

    return result2;
  }
}