Erlang syntax error before: 'end' - erlang

Question

I have recently started learning erlang, but have encountered an error that just leaves me puzzled.
The error is syntax error before: 'end' on the very last line. I have looked at examples an tried to find the error but I'm totally lost at the moment. Any Ideas?
ChannelToJoin = list:keysearch(ChannelName,1,State#server_st.channels),
case ChannelToJoin of
% Channel exists.
{value, Tuple} ->
if
%User is not a member of the channel
not list:member(UserID, Tuple) ->
%Add the user to the channel
Tuple#channel.users = list:append(Tuple#channel.users, [UserID]);
% If the user is already a member of the channel.
true -> true
end;
%Channel doesn't exist
false ->
%Create new channel and add the user to it.
NewState = State#server_st{channels = list:append(State#server_st.channels, NewChannel = #channel{name = ChannelName, users = [UserID]}
end

Answer 1

The second to last line, NewState = ..., is missing two closing parentheses: )}
Also note that you can't use lists:member inside if, as function calls are not allowed inside guard expressions (which is what if lets you use). Instead, use case:
case lists:member(UserID, Tuple#channel.users) of
false ->
%% Add the user to the channel
...;
true ->
%% Already a member
ok
end