changes to tab completion

* PacketCBTabComplete: options for completion should be seperated by
NUL
 * PluginManager: append an empty argument to arguments if command ends
with a whitespace (this will match all suggestions)
 * PlayerCommand: suggest only matching players instead of all players

api/src/main/java/net/md_5/bungee/api/plugin/PluginManager.java

@@ -137,7 +137,18 @@ public class PluginManager
             return true;
         }
 
-        String[] args = Arrays.copyOfRange( split, 1, split.length );
+        String[] args;
+
+        // add empty argument for tab completion
+        if ( commandLine.endsWith( " " ) )
+        {
+            args = Arrays.copyOfRange( split, 1, split.length + 1 );
+            args[ split.length - 1] = "";
+        } else
+        {
+            args = Arrays.copyOfRange( split, 1, split.length );
+        }
+
         try
         {
             if ( tabResults == null )

protocol/src/main/java/net/md_5/bungee/protocol/packet/PacketCBTabComplete.java

@@ -34,18 +34,13 @@ public class PacketCBTabComplete extends DefinedPacket
     @Override
     public void write(ByteBuf buf)
     {
-        String tab = "";
+        StringBuilder tab = new StringBuilder();
         for ( String alternative : commands )
         {
-            if ( tab.isEmpty() )
+            tab.append( alternative );
-            {
+            tab.append( "\00" );
-                tab = alternative + " ";
-            } else
-            {
-                tab += "\0" + alternative + " ";
-            }
         }
-        writeString( tab, buf );
+        writeString( tab.substring( 0, tab.length() - 1 ), buf );
     }
 
     @Override

proxy/src/main/java/net/md_5/bungee/command/PlayerCommand.java

@@ -1,6 +1,7 @@
 package net.md_5.bungee.command;
 
 import com.google.common.base.Function;
+import com.google.common.base.Predicate;
 import com.google.common.collect.Iterables;
 import net.md_5.bungee.api.CommandSender;
 import net.md_5.bungee.api.ProxyServer;
@@ -24,12 +25,20 @@ public abstract class PlayerCommand extends Command implements TabExecutor
     @Override
     public Iterable<String> onTabComplete(CommandSender sender, String[] args)
     {
-        return Iterables.transform( ProxyServer.getInstance().getPlayers(), new Function<ProxiedPlayer, String>()
+        final String lastArg = ( args.length > 0 ) ? args[args.length - 1] : "";
+        return Iterables.transform( Iterables.filter( ProxyServer.getInstance().getPlayers(), new Predicate<ProxiedPlayer>()
         {
             @Override
-            public String apply(ProxiedPlayer input)
+            public boolean apply(ProxiedPlayer player)
             {
-                return input.getDisplayName();
+                return player.getName().startsWith( lastArg );
+            }
+        } ), new Function<ProxiedPlayer, String>()
+        {
+            @Override
+            public String apply(ProxiedPlayer player)
+            {
+                return player.getName();
             }
         } );
     }