impl: fallback server (#8)

* impl: fallback server

* fix fallback fetch

Author: tunikakeks

src/main/java/de/redstonecloud/bridge/platform/waterdogpe/WDPEHandler.java

@@ -1,5 +1,6 @@
 package de.redstonecloud.bridge.platform.waterdogpe;
 
+import com.google.gson.JsonObject;
 import de.redstonecloud.api.redis.broker.packet.defaults.template.BestTemplateResultPacket;
 import de.redstonecloud.api.redis.broker.packet.defaults.template.GetBestTemplatePacket;
 import de.redstonecloud.bridge.cloudinterface.CloudInterface;
@@ -29,12 +30,12 @@ public WDPEHandler(
 
     @Override
     public ServerInfo resolveForcedHost(@Nullable String domain, @NonNull ProxiedPlayer player) {
-        return fetchServer();
+        return fetchServer(player);
     }
 
     @Override
     public ServerInfo getFallbackServer(ProxiedPlayer player, ServerInfo oldServer, ReconnectReason reason, String kickMessage) {
-        return fetchServer();
+        return fetchServer(player);
     }
 
     @Override
@@ -43,16 +44,33 @@ public ServerInfo getFallbackServer(
             @NonNull ServerInfo oldServer,
             @NonNull String kickMessage
     ) {
-        return fetchServer();
+        return fetchServer(player);
     }
 
     @Override
     public ServerInfo determineServer(ProxiedPlayer player) {
-        return fetchServer();
+        return fetchServer(player);
     }
 
-    public static ServerInfo fetchServer() {
-        if(!CloudInterface.getBridgeConfig().has("hub_template")) return null;
+    public static ServerInfo fetchServer(ProxiedPlayer player) {
+        JsonObject cfg = CloudInterface.getBridgeConfig();
+        ServerInfo fallback = fetchFallback();
+        if(!cfg.has("hub_template")) return fallback;
+        boolean fallbackOnJoin = !cfg.has("fallback_on_join") || cfg.get("fallback_on_join").getAsBoolean();
+
+        if(!cfg.has("hub_template"))
+            return fallback;
+
+        ServerInfo hub = fetchHub();
+        if(hub != null) return hub;
+
+        if(player.getDownstreamConnection() != null && fallbackOnJoin)
+            return fallback;
+
+        return null;
+    }
+
+    public static ServerInfo fetchHub() {
         CompletableFuture<String> name = new CompletableFuture<>();
 
         new GetBestTemplatePacket(CloudInterface.getBridgeConfig().get("hub_template").getAsString())
@@ -61,9 +79,17 @@ public static ServerInfo fetchServer() {
 
         try {
             BridgeServer srv = CloudInterface.getExecutor().determineServer(name.completeOnTimeout("", 3, TimeUnit.SECONDS).get().toUpperCase());
+            if(srv == null) return null;
+
             return ProxyServer.getInstance().getServerInfo(srv.getName());
         } catch (Exception e) {
             return null;
         }
     }
+
+    public static ServerInfo fetchFallback() {
+        JsonObject cfg = CloudInterface.getBridgeConfig();
+        if(!cfg.has("fallback_name")) return null;
+        return ProxyServer.getInstance().getServerInfo(cfg.get("fallback_name").getAsString());
+    }
 }

src/main/java/de/redstonecloud/bridge/platform/waterdogpe/commands/HubCommand.java

@@ -19,7 +19,7 @@ public HubCommand() {
     @Override
     public boolean onExecute(CommandSender sender, String alias, String[] args) {
         if(!(sender instanceof ProxiedPlayer)) return false;
-        ServerInfo hub = WDPEHandler.fetchServer();
+        ServerInfo hub = WDPEHandler.fetchServer((ProxiedPlayer) sender);
         if(hub == null) {
             sender.sendMessage(CloudInterface.getBridgeConfig().has("hubcommand_no_hub_available") ? CloudInterface.getBridgeConfig().get("hubcommand_no_hub_available").getAsString() : "No hub available");
             return true;