async Task <int> FetchNewMessages(IChatMessageOptions options, CancellationToken token)
{
IEnumerable <IChatMessage> messages = null;
int count = 0;
if (!token.IsCancellationRequested)
{
await ssFetch.WaitAsync(token);
try
{
messages = await GitterApi.GetChatMessages(ChatRoom.Id, options);
if (messages is object)
{
count = messages.Count();
if (!string.IsNullOrWhiteSpace(options.BeforeId))
{
Messages.InsertRange(0, RemoveDuplicates(Messages, messages));
}
else
{
Messages.AddRange(RemoveDuplicates(Messages, messages));
}
await Invoke(StateHasChanged);
await Task.Delay(1);
}
}
catch (Exception e)
{
Console.WriteLine($"RoomMessages.FetchNewMessages: {e.GetBaseException().Message}");
}
finally
{
ssFetch.Release();
}
}
return(count);
IEnumerable <IChatMessage> RemoveDuplicates(IEnumerable <IChatMessage> Existing, IEnumerable <IChatMessage> Merging)
{
IEnumerable <string> ExistingIds = Existing.Select(m => m.Id);
return(Merging.Where(m => !ExistingIds.Contains(m.Id)));
}
}