Introduce backend synchronization system for Velocity and WebsiteBackend

VelocityCore/src/de/steamwar/velocitycore/BackendSync.java

@@ -0,0 +1,96 @@
+/*
+ *   This file is a part of the SteamWar software.
+ *
+ *   Copyright (C) 2025 SteamWar.de-Serverteam
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU Affero General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU Affero General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Affero General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.velocitycore;
+
+import de.steamwar.data.SyncCommands;
+import de.steamwar.sql.Event;
+import de.steamwar.sql.EventFight;
+import de.steamwar.sql.SteamwarUser;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.*;
+
+public class BackendSync implements Runnable {
+    private static final Path syncPath = new File("/run/sync").toPath();
+    private final Thread thread;
+    private final WatchService watchService;
+
+    public BackendSync() {
+        try {
+            watchService
+                    = FileSystems.getDefault().newWatchService();
+        } catch (IOException e) {
+            throw new SecurityException("Could not create watch service", e);
+        }
+
+
+        thread = new Thread(this, "BackendSync");
+        thread.start();
+    }
+
+    public void stop() {
+        try {
+            watchService.close();
+            thread.join();
+        } catch (IOException | InterruptedException e) {
+            Thread.currentThread().interrupt();
+        }
+    }
+
+    private void handleCommand(String name) {
+        try {
+            String[] parts = name.split("\\.");
+
+            switch (parts[0]) {
+                case SyncCommands.RELOAD_EVENT -> EventFight.loadAllComingFights();
+                case SyncCommands.RELOAD_PLAYER -> SteamwarUser.invalidate(Integer.parseInt(parts[1]));
+                default -> VelocityCore.getLogger().warning("Unknown command: " + name);
+            }
+        } catch (Exception e) {
+            VelocityCore.getLogger().throwing(this.getClass().getName(), "handleCommand", e);
+        }
+    }
+
+    @Override
+    public void run() {
+        try {
+            syncPath.register(watchService,
+                    java.nio.file.StandardWatchEventKinds.ENTRY_CREATE);
+
+            WatchKey key;
+            while ((key = watchService.take()) != null) {
+                for (WatchEvent<?> event : key.pollEvents()) {
+                    String command = event.context().toString();
+                    handleCommand(command);
+
+                    if (!VelocityCore.get().getConfig().isEventmode()) {
+                        Path path = syncPath.resolve((Path) event.context());
+                        Files.delete(path);
+                    }
+                }
+            }
+        } catch (InterruptedException | ClosedWatchServiceException ignored) {
+            Thread.currentThread().interrupt();
+        } catch (Exception e) {
+            VelocityCore.getLogger().throwing(this.getClass().getName(), "run", e);
+        }
+    }
+}

VelocityCore/src/de/steamwar/velocitycore/VelocityCore.java

@@ -95,6 +95,7 @@ public class VelocityCore implements ReloadablePlugin {
     private Config config;
     private ErrorLogger errorLogger;
     private TablistManager tablistManager;
+    private BackendSync backendSync;
 
     @Getter
     private TeamCommand teamCommand;
@@ -147,6 +148,8 @@ public class VelocityCore implements ReloadablePlugin {
         new ReplayMod();
         new FML2();
 
+        backendSync = new BackendSync();
+
         new ConnectionListener();
         new ChatListener();
         new BanListener();
@@ -268,6 +271,8 @@ public class VelocityCore implements ReloadablePlugin {
             logger.log(Level.SEVERE, "Could not shutdown discord bot", e);
         }
 
+        backendSync.stop();
+
         if(tablistManager != null)
             tablistManager.disable();
         errorLogger.unregister();