/// <summary>
/// Saves an item to the list. If the item does not have an Id, then the item
/// is considered new and will be added to the end of the list. Otherwise, the
/// item is considered existing and is replaced.
/// </summary>
/// <param name="item">The new item</param>
/// <returns>A task that completes when the item is saved.</returns>
public Task SaveItemAsync(TodoItem item)
{
if (item == null)
{
throw new ArgumentNullException(nameof(item));
}
item.Version = Guid.NewGuid().ToString();
item.UpdatedAt = DateTimeOffset.UtcNow;
if (item.Id == null)
{
item.Id = Guid.NewGuid().ToString();
_items.Add(item);
TodoItemsUpdated?.Invoke(this, new TodoServiceEventArgs(TodoServiceEventArgs.ListAction.Add, item));
}
else
{
var itemToReplace = _items.SingleOrDefault(m => m.Id == item.Id);
if (itemToReplace != null)
{
var idx = _items.IndexOf(itemToReplace);
_items[idx] = item;
TodoItemsUpdated?.Invoke(this, new TodoServiceEventArgs(TodoServiceEventArgs.ListAction.Update, item));
}
}
return(Task.CompletedTask);
}
/// <summary>
/// Removes an item in the list, if it exists.
/// </summary>
/// <param name="item">The item to be removed</param>
/// <returns>A task that completes when the item is removed.</returns>
public Task RemoveItemAsync(TodoItem item)
{
if (item == null)
{
throw new ArgumentNullException(nameof(item));
}
if (item.Id != null)
{
var itemToRemove = _items.SingleOrDefault(m => m.Id == item.Id);
if (itemToRemove != null)
{
_items.Remove(itemToRemove);
TodoItemsUpdated?.Invoke(this, new TodoServiceEventArgs(TodoServiceEventArgs.ListAction.Delete, itemToRemove));
}
}
return(Task.CompletedTask);
}
