Add Op login hint in the next start after restoring

README.md

@@ -67,7 +67,6 @@ done
 
 ## 3. To-Do List:
 
-- Op login hint in the next start after restoring
 - A more friendly help menu (colored command help menu)
 - New version checker
 - Code refactor for maintainability

gradle.properties

@@ -6,7 +6,7 @@ minecraft_version=1.14.4
 yarn_mappings=1.14.4+build.18
 loader_version=0.11.0
 # Mod Properties
-mod_version=1.6.2
+mod_version=1.6.3
 maven_group=com.keuin.kbackupfabric
 archives_base_name=kbackup-fabric
 # Dependencies

src/main/java/com/keuin/kbackupfabric/KBPluginEvents.java

@@ -2,8 +2,11 @@
 
 import com.keuin.kbackupfabric.backup.BackupFilesystemUtil;
 import com.keuin.kbackupfabric.backup.suggestion.BackupNameSuggestionProvider;
+import com.keuin.kbackupfabric.event.OnPlayerConnect;
 import com.keuin.kbackupfabric.metadata.BackupMetadata;
 import com.keuin.kbackupfabric.metadata.MetadataHolder;
+import com.keuin.kbackupfabric.notification.DistinctNotifiable;
+import com.keuin.kbackupfabric.notification.NotificationManager;
 import com.keuin.kbackupfabric.ui.KBCommands;
 import com.keuin.kbackupfabric.util.DateUtil;
 import com.keuin.kbackupfabric.util.PrintUtil;
@@ -41,6 +44,11 @@ public void onStartServer(MinecraftServer server) {
         if (!(server instanceof MinecraftDedicatedServer))
             throw new RuntimeException("KBackup is a server-side-only plugin. Please do not use it in client-side.");
 
+        // Bind fabric events
+
+        OnPlayerConnect.ON_PLAYER_CONNECT.register((connection, player)
+                -> NotificationManager.INSTANCE.notifyPlayer(DistinctNotifiable.fromServerPlayerEntity(player)));
+
         // Initialize player manager reference
         PrintUtil.setPlayerManager(server.getPlayerManager());
 

src/main/java/com/keuin/kbackupfabric/event/OnPlayerConnect.java

@@ -0,0 +1,18 @@
+package com.keuin.kbackupfabric.event;
+
+import net.fabricmc.fabric.api.event.Event;
+import net.fabricmc.fabric.api.event.EventFactory;
+import net.minecraft.network.ClientConnection;
+import net.minecraft.server.network.ServerPlayerEntity;
+
+public class OnPlayerConnect {
+    public interface PlayerConnectEventCallback {
+        void onPlayerConnect(ClientConnection connection, ServerPlayerEntity player);
+    }
+
+    public static final Event<PlayerConnectEventCallback> ON_PLAYER_CONNECT = EventFactory.createArrayBacked(PlayerConnectEventCallback.class, callbacks -> (conn, player) -> {
+        for (PlayerConnectEventCallback callback : callbacks) {
+            callback.onPlayerConnect(conn, player);
+        }
+    });
+}

src/main/java/com/keuin/kbackupfabric/mixin/PlayerManagerMixin.java

@@ -0,0 +1,18 @@
+package com.keuin.kbackupfabric.mixin;
+
+import com.keuin.kbackupfabric.event.OnPlayerConnect;
+import net.minecraft.network.ClientConnection;
+import net.minecraft.server.PlayerManager;
+import net.minecraft.server.network.ServerPlayerEntity;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+@Mixin(PlayerManager.class)
+public class PlayerManagerMixin {
+    @Inject(method = "onPlayerConnect", at = @At("TAIL"))
+    public void onPlayerConnect(ClientConnection connection, ServerPlayerEntity player, CallbackInfo ci) {
+        OnPlayerConnect.ON_PLAYER_CONNECT.invoker().onPlayerConnect(connection, player);
+    }
+}

src/main/java/com/keuin/kbackupfabric/notification/DistinctNotifiable.java

@@ -0,0 +1,45 @@
+package com.keuin.kbackupfabric.notification;
+
+import net.minecraft.network.MessageType;
+import net.minecraft.server.network.ServerPlayerEntity;
+import net.minecraft.text.Text;
+
+/**
+ * Decouple from ServerPlayerEntity, in case further migration to other APIs.
+ */
+public interface DistinctNotifiable {
+
+    /**
+     * Does the receiver has privilege to receive some special message.
+     */
+    boolean isPrivileged();
+
+    void notify(Text text);
+
+    /**
+     * Get an unique, non-null object that identifies this notifiable instance.
+     * The identifier must be immutable and implement their own equals method.
+     *
+     * @return the identifier.
+     */
+    Object getIdentifier();
+
+    static DistinctNotifiable fromServerPlayerEntity(ServerPlayerEntity serverPlayerEntity) {
+        return new DistinctNotifiable() {
+            @Override
+            public boolean isPrivileged() {
+                return serverPlayerEntity.server.getPermissionLevel(serverPlayerEntity.getGameProfile()) >= serverPlayerEntity.server.getOpPermissionLevel();
+            }
+
+            @Override
+            public void notify(Text text) {
+                serverPlayerEntity.sendChatMessage(text, MessageType.SYSTEM);
+            }
+
+            @Override
+            public Object getIdentifier() {
+                return serverPlayerEntity.getUuid();
+            }
+        };
+    }
+}

src/main/java/com/keuin/kbackupfabric/notification/NotificationManager.java

@@ -0,0 +1,49 @@
+package com.keuin.kbackupfabric.notification;
+
+import com.keuin.kbackupfabric.metadata.BackupMetadata;
+import com.keuin.kbackupfabric.metadata.MetadataHolder;
+import com.keuin.kbackupfabric.util.DateUtil;
+import net.minecraft.text.LiteralText;
+import net.minecraft.text.Style;
+import net.minecraft.util.Formatting;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * Notify some users when the server has been restored to a backup.
+ */
+public class NotificationManager {
+
+    public static final NotificationManager INSTANCE = new NotificationManager();
+
+    private final Set<Object> notified = new HashSet<>();
+
+    private NotificationManager() {
+    }
+
+    public void notifyPlayer(DistinctNotifiable distinctNotifiable) {
+        Object identifier = distinctNotifiable.getIdentifier();
+        if (distinctNotifiable.isPrivileged() && !notified.contains(identifier)) {
+            notified.add(identifier);
+            notify(distinctNotifiable);
+        }
+    }
+
+    /**
+     * Just notify if necessary. It will not update the set.
+     */
+    private void notify(DistinctNotifiable notifiable) {
+        if (MetadataHolder.hasMetadata()) {
+            BackupMetadata backup = MetadataHolder.getMetadata();
+            notifiable.notify(
+                    new LiteralText("The server has been restored to backup ")
+                            .append(new LiteralText("[" + backup.getBackupName() + "]").setStyle(new Style().setColor(Formatting.GREEN)))
+                            .append(new LiteralText(" (created at "))
+                            .append(new LiteralText("[" + DateUtil.fromEpochMillis(backup.getBackupTime()) + "]").setStyle(new Style().setColor(Formatting.GREEN)))
+                            .append(new LiteralText(")"))
+            );
+        }
+    }
+
+}

src/main/java/com/keuin/kbackupfabric/ui/KBCommands.java

@@ -288,7 +288,7 @@ public static int restore(CommandContext<ServerCommandSource> context) {
             //KBMain.restore("name")
             MinecraftServer server = context.getSource().getMinecraftServer();
             String backupFileName = parseBackupFileName(context, StringArgumentType.getString(context, "backupName"));
-            backupFileName = parseBackupFileName(context, backupFileName);
+//            backupFileName = parseBackupFileName(context, backupFileName);
 
             if (backupFileName == null)
                 return list(context); // Show the list and return
@@ -501,7 +501,7 @@ private static String parseBackupFileName(CommandContext<ServerCommandSource> co
             String backupName = StringArgumentType.getString(context, "backupName");
 
             if (backupName.matches("[0-9]*")) {
-                // If numeric input
+                // treat numeric input as backup index number in list
                 int index = Integer.parseInt(backupName) - 1;
                 synchronized (backupList) {
                     return backupList.get(index).getBackupFileName(); // Replace input number with real backup file name.

src/main/resources/fabric.mod.json

@@ -20,6 +20,7 @@
     ]
   },
   "mixins": [
+    "kbackupfabric.mixins.json"
   ],
   "depends": {
     "fabricloader": ">=0.7.4",

src/main/resources/kbackupfabric.mixins.json

@@ -0,0 +1,16 @@
+{
+  "required": true,
+  "package": "com.keuin.kbackupfabric.mixin",
+  "compatibilityLevel": "JAVA_8",
+  "mixins": [
+    "PlayerManagerMixin"
+  ],
+  "client": [
+  ],
+  "server": [
+  ],
+  "injectors": {
+    "defaultRequire": 1
+  },
+  "verbose": true
+}