Fix Region.backup size

Signed-off-by: yoyosource <yoyosource@nidido.de>

BauSystem_Main/src/de/steamwar/bausystem/features/backup/BackupCommand.java

@@ -28,7 +28,6 @@ import de.steamwar.bausystem.region.tags.Tag;
 import de.steamwar.command.SWCommand;
 import de.steamwar.command.SWCommandUtils;
 import de.steamwar.command.TypeMapper;
-import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
 
 import java.util.Collections;

BauSystem_Main/src/de/steamwar/bausystem/region/Region.java

@@ -466,6 +466,14 @@ public class Region {
         final File definedBackupFolder = new File(new File(backupFolder, prototype.getName()), name);
         //noinspection ResultOfMethodCallIgnored
         definedBackupFolder.mkdirs();
+
+        File[] currentBackups = definedBackupFolder.listFiles();
+        if (currentBackups.length >= 20) {
+            List<File> files = new ArrayList<>(Arrays.asList(currentBackups));
+            files.sort(Comparator.comparingLong(File::lastModified));
+            while (files.size() >= 20) files.remove(0).delete();
+        }
+
         final File backupFile = new File(definedBackupFolder, LocalDateTime.now().format(formatter) + ".schem");
         //noinspection unchecked
         return VersionedCallable.call(new VersionedCallable<>(() -> Region_15.backup(minPoint, maxPoint, backupFile), 15));