public MainPageViewModel(INavigationService navigationService)
: base(navigationService)
{
Title = "Todo List";
var query = CrossCloudFirestore.Current
.Instance
.GetCollection(TodoItem.CollectionPath)
.OrderBy(nameof(TodoItem.CreatedAt), true);
query.ObserveAdded()
.Select(change => (Object: change.Document.ToObject <TodoItem>(), Index: change.NewIndex))
.Select(t => (ViewModel: new TodoItemViewModel(t.Object), Index: t.Index))
.Subscribe(t => TodoItems.InsertOnScheduler(t.Index, t.ViewModel))
.AddTo(_disposables);
query.ObserveModified()
.Select(change => change.Document.ToObject <TodoItem>())
.Select(todoItem => (TodoItem: todoItem, ViewModel: TodoItems.FirstOrDefault(x => x.Id == todoItem.Id)))
.Where(t => t.ViewModel != null)
.Subscribe(t => t.ViewModel.Update(t.TodoItem.Name, t.TodoItem.Notes))
.AddTo(_disposables);
query.ObserveRemoved()
.Select(change => TodoItems.FirstOrDefault(x => x.Id == change.Document.Id))
.Where(viewModel => viewModel != null)
.Subscribe(viewModel => TodoItems.RemoveOnScheduler(viewModel))
.AddTo(_disposables);
AddCommand = new ReactiveCommand();
AddCommand.Subscribe(() =>
{
navigationService.NavigateAsync <NewTodoItemPageViewModel>(useModalNavigation: true, wrapInNavigationPage: true);
});
SelectItemCommand = new ReactiveCommand <TodoItemViewModel>();
SelectItemCommand.Subscribe(item =>
{
navigationService.NavigateAsync <TodoItemDetailPageViewModel, string>(item.Id);
});
}