From 8ee69a40c7782a69d44b9be08538cbe17531420b Mon Sep 17 00:00:00 2001
From: Alexander Sulfrian <alexander@sulfrian.net>
Date: Thu, 14 Oct 2010 16:05:14 +0200
Subject: code cleanup, added comments

---
 client/client.erl | 51 ++++++++++++++++++++-------------------------------
 1 file changed, 20 insertions(+), 31 deletions(-)

diff --git a/client/client.erl b/client/client.erl
index 46ef59f..0e2fada 100644
--- a/client/client.erl
+++ b/client/client.erl
@@ -1,19 +1,15 @@
 -module(client).
 -export([register/3, login/3, list/0, handle/2, getVotes/0, vote/2, devote/2]).
 
-contains([], _) ->
-    false;
-contains([H|_], H) ->
-    true;
-contains([_|T], Search) ->
-    contains(T, Search).
-
 checkLogin(Value) ->
-    checkLogin(Value, contains(registered(), cli)).
-checkLogin(Value, Value) ->
-    true;
-checkLogin(_, _) ->
-    throw({error, login_state}).
+    %% check if user meets the requirements to be locked in or not by
+    %% locking in to the registered processes and check if the cli
+    %% process is registered
+    LoggedIn = lists:member(cli, registered()),
+    if LoggedIn == Value ->
+	    true;
+       true -> throw({error, login_state})
+    end.
 
 buildNode(Server) ->
     list_to_atom("distributed_music_system_main_node@" ++ Server).
@@ -82,33 +78,26 @@ handle({change_state, NewState}, _) ->
 handle(Cmd, Server) ->
     {{error, {unknown_command, Cmd}}, Server}.
 
-%queries the server for the current votes this client possesses
-getVotes() ->
+try_logged_in_rpc(Rpc) ->
+    %% tries to execute an rpc for logged in user and returns error
+    %% message if user is not logged in
     try checkLogin(true) of
 	_ ->
-	    server:rpc(cli, get_votes)
+	    server:rpc(cli, Rpc)
     catch
 	{error, login_state} ->
 	    {error, not_logged_in}
     end.
 
-%positive vote, increments the votes for {Artist, Title} by one
+getVotes() ->
+    %% queries the server for the current votes this client possesses
+    try_logged_in_rpc(get_votes).
+
 vote(Artist, Title) ->
-    try checkLogin(true) of
-	_ ->
-	    server:rpc(cli, {vote, Artist, Title})
-    catch
-	{error, login_state} ->
-	    {error, not_logged_in}
-    end.
+    %% positive vote, increments the votes for {Artist, Title} by one
+    try_logged_in_rpc({vote, Artist, Title}).
 
-%negative vote, decrements the votes for {Artist, Title} by one
 devote(Artist, Title) ->
-    try checkLogin(true) of
-	_ ->
-	    server:rpc(cli, {devote, Artist, Title})
-    catch
-	{error, login_state} ->
-	    {error, not_logged_in}
-    end.
+    %% negative vote, decrements the votes for {Artist, Title} by one
+    try_logged_in_rpc({devote, Artist, Title}).
 
-- 
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