From 4a77a0c6b9df61ce8c95f244051853f4310c81b0 Mon Sep 17 00:00:00 2001
From: Techcable <Techcable@outlook.com>
Date: Thu, 28 Jan 2016 15:13:29 -0700
Subject: [PATCH] Allow removing servers or changing addresses on reload

Moves all players on the removed server to the default server.
Address changes also move the players to the default server.
Kicks players on failure to move.

Original Issue: https://github.com/WaterfallMC/Waterfall-Old/issues/17

diff --git a/proxy/src/main/java/net/md_5/bungee/conf/Configuration.java b/proxy/src/main/java/net/md_5/bungee/conf/Configuration.java
index 1c585e60..bdb012c3 100644
--- a/proxy/src/main/java/net/md_5/bungee/conf/Configuration.java
+++ b/proxy/src/main/java/net/md_5/bungee/conf/Configuration.java
@@ -11,12 +11,15 @@ import java.util.UUID;
 import java.util.logging.Level;
 import javax.imageio.ImageIO;
 import lombok.Getter;
+
+import net.md_5.bungee.BungeeCord;
 import net.md_5.bungee.api.Favicon;
 import net.md_5.bungee.api.ProxyConfig;
 import net.md_5.bungee.api.ProxyServer;
 import net.md_5.bungee.api.config.ConfigurationAdapter;
 import net.md_5.bungee.api.config.ListenerInfo;
 import net.md_5.bungee.api.config.ServerInfo;
+import net.md_5.bungee.api.connection.ProxiedPlayer;
 import net.md_5.bungee.util.CaseInsensitiveMap;
 import net.md_5.bungee.util.CaseInsensitiveSet;
 
@@ -103,18 +106,31 @@ public abstract class Configuration implements ProxyConfig
             servers = new CaseInsensitiveMap<>( newServers );
         } else
         {
-            for ( ServerInfo oldServer : servers.values() )
-            {
-                // Don't allow servers to be removed
-                Preconditions.checkArgument( newServers.containsKey( oldServer.getName() ), "Server %s removed on reload!", oldServer.getName() );
-            }
+            Map<String, ServerInfo> oldServers = this.servers;
+            this.servers = new CaseInsensitiveMap<>(newServers);
 
-            // Add new servers
-            for ( Map.Entry<String, ServerInfo> newServer : newServers.entrySet() )
+            for ( ServerInfo oldServer : oldServers.values() )
             {
-                if ( !servers.containsValue( newServer.getValue() ) )
-                {
-                    servers.put( newServer.getKey(), newServer.getValue() );
+                ServerInfo newServer = newServers.get(oldServer.getName());
+                if ((newServer == null || !oldServer.getAddress().equals(newServer.getAddress())) && !oldServer.getPlayers().isEmpty()) {
+                    BungeeCord.getInstance().getLogger().info("Moving players off of server: " + oldServer.getName());
+                    // The server is being removed, or having it's address changed
+                    for (ProxiedPlayer player : oldServer.getPlayers()) {
+                        ListenerInfo listener = player.getPendingConnection().getListener();
+                        String destinationName = newServers.get(listener.getDefaultServer()) == null ? listener.getDefaultServer() : listener.getFallbackServer();
+                        ServerInfo destination = newServers.get(destinationName);
+                        if (destination == null) {
+                            BungeeCord.getInstance().getLogger().severe("Couldn't find server " + listener.getDefaultServer() + " or " + listener.getFallbackServer() + " to put player " + player.getName() + " on");
+                            player.disconnect(BungeeCord.getInstance().getTranslation("fallback_kick", "Not found on reload"));
+                            continue;
+                        }
+                        player.connect(destination, (success, cause) -> {
+                            if (!success) {
+                                BungeeCord.getInstance().getLogger().log(Level.WARNING, "Failed to connect " + player.getName() + " to " + destination.getName(), cause);
+                                player.disconnect(BungeeCord.getInstance().getTranslation("fallback_kick", cause.getCause().getClass().getName()));
+                            }
+                        });
+                    }
                 }
             }
         }
-- 
2.19.0