feat(stealth): mask identities and notify admins on login

src/test/java/games/dmg/spigotstealth/BukkitIdentityPresentationTest.java

@@ -25,10 +25,14 @@ class BukkitIdentityPresentationTest {
         BukkitIdentityPresentation presentation = new BukkitIdentityPresentation(
                 () -> List.of(target), scoreboard, mock(TabListController.class));
 
+        when(target.getDisplayName()).thenReturn("Original Alex");
+        presentation.conceal(target);
         presentation.conceal(target);
         presentation.reveal(target);
 
-        verify(target).setSleepingIgnored(true);
+        verify(target).setDisplayName("Original Alex");
+        org.junit.jupiter.api.Assertions.assertTrue(presentation.concealedNames().isEmpty());
+        verify(target, org.mockito.Mockito.times(2)).setSleepingIgnored(true);
         verify(target).setSleepingIgnored(false);
     }
 
@@ -73,7 +77,7 @@ class BukkitIdentityPresentationTest {
     }
 
     @Test
-    void concealRemovesTabEntryAndHidesNameTagWithoutHidingEntity() {
+    void concealRemovesTabEntryAndScramblesNameTagWithoutHidingEntity() {
         UUID targetId = UUID.randomUUID();
         Player target = player(targetId, "Alex");
         Player observer = player(UUID.randomUUID(), "Morgan");
@@ -87,7 +91,11 @@ class BukkitIdentityPresentationTest {
 
         presentation.conceal(target);
 
-        verify(team).setOption(Team.Option.NAME_TAG_VISIBILITY, Team.OptionStatus.NEVER);
+        verify(team).setOption(Team.Option.NAME_TAG_VISIBILITY, Team.OptionStatus.ALWAYS);
+        verify(team).setPrefix("§k");
+        verify(team).setSuffix("§r");
+        verify(target).setDisplayName("§kAnonymous§r");
+        org.junit.jupiter.api.Assertions.assertEquals(java.util.Set.of("Alex"), presentation.concealedNames());
         verify(team).addEntry("Alex");
         verify(tabLists).remove(observer, targetId);
         verify(observer, never()).hidePlayer(org.mockito.ArgumentMatchers.any(), org.mockito.ArgumentMatchers.any());

src/test/java/games/dmg/spigotstealth/IdentityPacketFieldsTest.java

@@ -0,0 +1,32 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+import org.junit.jupiter.api.Test;
+
+class IdentityPacketFieldsTest {
+    private final StealthChatMasker masker = new StealthChatMasker(Set.of("Secret"));
+
+    record Entry(String text, Optional<String> tooltip) { }
+    record Bound(int chatType, String name, Optional<String> targetName) { }
+
+    @Test
+    void filtersModernSuggestionEntriesWithoutChangingOrdinaryEntries() throws ReflectiveOperationException {
+        Entry ordinary = new Entry("Someone", Optional.of("help"));
+        List<Entry> entries = List.of(new Entry("sEcReT", Optional.empty()), ordinary);
+        assertEquals(List.of(ordinary), IdentityPacketFields.filterEntries(entries, masker));
+        assertEquals(2, entries.size());
+    }
+
+    @Test
+    void rebuildsDisplayNameRecordWithoutMutatingOriginal() throws ReflectiveOperationException {
+        Bound original = new Bound(42, "Secret", Optional.of("Secret"));
+        Object copy = IdentityPacketFields.mapRecord(original,
+                value -> value.equals("Secret") ? "Anonymous" : value);
+        assertEquals(new Bound(42, "Anonymous", Optional.of("Anonymous")), copy);
+        assertEquals("Secret", original.name());
+    }
+}

src/test/java/games/dmg/spigotstealth/ProtocolLibIdentityMaskingListenerTest.java

@@ -0,0 +1,63 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import com.comphenix.protocol.PacketType;
+import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.utility.MinecraftReflection;
+import com.comphenix.protocol.utility.MinecraftVersion;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicReference;
+import org.bukkit.plugin.Plugin;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.mockito.MockedStatic;
+
+class ProtocolLibIdentityMaskingListenerTest {
+    private static MockedStatic<MinecraftReflection> reflection;
+
+    @BeforeAll
+    static void initializeProtocolTypesWithoutServer() {
+        MinecraftVersion.setCurrentVersion(new MinecraftVersion(1, 21, 8));
+        reflection = mockStatic(MinecraftReflection.class);
+    }
+
+    @AfterAll
+    static void resetProtocolEnvironment() {
+        reflection.close();
+        MinecraftVersion.setCurrentVersion(null);
+    }
+
+    @Test
+    void skipsPacketWorkWhenNobodyIsConcealed() {
+        AtomicReference<Set<String>> names = new AtomicReference<>(Set.of());
+        var listener = new ProtocolLibIdentityMaskingListener(mock(Plugin.class), names::get, ignored -> { });
+        PacketEvent event = mock(PacketEvent.class);
+        listener.onPacketSending(event);
+        verify(event, never()).getPacket();
+        assertTrue(listener.getSendingWhitelist().getTypes().contains(PacketType.Play.Server.CHAT));
+        assertTrue(listener.getSendingWhitelist().getTypes().contains(PacketType.Play.Server.SYSTEM_CHAT));
+    }
+
+    @Test
+    void readsFreshSnapshotAndWarnsOnceWithoutCancellingOrReplacingFailedPacket() {
+        List<String> warnings = new ArrayList<>();
+        AtomicReference<Set<String>> names = new AtomicReference<>(Set.of());
+        var listener = new ProtocolLibIdentityMaskingListener(mock(Plugin.class), names::get, warnings::add);
+        PacketEvent event = mock(PacketEvent.class);
+        when(event.getPacketType()).thenReturn(PacketType.Play.Server.CHAT);
+        listener.onPacketSending(event);
+        assertTrue(warnings.isEmpty());
+        names.set(Set.of("Secret"));
+        // No real NMS packet: the clone attempt fails and must leave event delivery untouched.
+        listener.onPacketSending(event);
+        listener.onPacketSending(event);
+        assertEquals(1, warnings.size());
+        verify(event, never()).setPacket(any());
+        verify(event, never()).setCancelled(anyBoolean());
+    }
+}

src/test/java/games/dmg/spigotstealth/StealthAdminJoinListenerTest.java

@@ -0,0 +1,83 @@
+package games.dmg.spigotstealth;
+
+import static org.mockito.Mockito.*;
+
+import java.util.List;
+import java.util.Set;
+import java.util.UUID;
+import org.bukkit.entity.Player;
+import org.bukkit.event.player.PlayerJoinEvent;
+import org.junit.jupiter.api.Test;
+
+class StealthAdminJoinListenerTest {
+    @Test
+    void joiningAdminReceivesCountButExistingAdminsDoNotReceiveOrdinaryJoinNotice() {
+        Player joining = player(true);
+        Player existing = player(true);
+        StealthSessionService sessions = sessions(Set.of(UUID.randomUUID(), UUID.randomUUID()));
+        new StealthAdminJoinListener(sessions, () -> List.of(joining, existing)).onJoin(event(joining));
+        verify(joining).sendMessage("[Stealth] 2 players are invisible. Use /stealthadmin list to see who.");
+        verify(existing, never()).sendMessage(anyString());
+    }
+
+    @Test
+    void concealedJoinNotifiesOnlyAdminsWithUpdatedCount() {
+        Player joining = player(false);
+        Player admin = player(true);
+        Player ordinary = player(false);
+        StealthSessionService sessions = sessions(Set.of(joining.getUniqueId()));
+        new StealthAdminJoinListener(sessions, () -> List.of(joining, admin, ordinary)).onJoin(event(joining));
+        verify(admin).sendMessage("[Stealth] An invisible player joined. 1 player is now invisible. Use /stealthadmin list to see who.");
+        verify(joining, never()).sendMessage(anyString());
+        verify(ordinary, never()).sendMessage(anyString());
+    }
+
+    @Test
+    void concealedAdminGetsExactlyOneNoticeEvenWhenIncludedInOnlinePlayers() {
+        Player joining = player(true);
+        Player admin = player(true);
+        StealthSessionService sessions = sessions(Set.of(joining.getUniqueId(), UUID.randomUUID()));
+        new StealthAdminJoinListener(sessions, () -> List.of(joining, admin)).onJoin(event(joining));
+        verify(joining, times(1)).sendMessage("[Stealth] 2 players are invisible. Use /stealthadmin list to see who.");
+        verify(admin).sendMessage("[Stealth] An invisible player joined. 2 players are now invisible. Use /stealthadmin list to see who.");
+    }
+
+    @Test
+    void zeroCountIsSilent() {
+        Player joining = player(true);
+        new StealthAdminJoinListener(sessions(Set.of()), () -> List.of(joining)).onJoin(event(joining));
+        verify(joining, never()).sendMessage(anyString());
+    }
+
+    @Test
+    void ordinaryJoinIsSilentAndSinglePlayerCountUsesSingular() {
+        Player ordinary = player(false);
+        Player admin = player(true);
+        StealthAdminJoinListener listener = new StealthAdminJoinListener(
+                sessions(Set.of(UUID.randomUUID())), () -> List.of(ordinary, admin));
+        listener.onJoin(event(ordinary));
+        verify(ordinary, never()).sendMessage(anyString());
+        verify(admin, never()).sendMessage(anyString());
+        listener.onJoin(event(admin));
+        verify(admin).sendMessage("[Stealth] 1 player is invisible. Use /stealthadmin list to see who.");
+    }
+
+    private static StealthSessionService sessions(Set<UUID> ids) {
+        StealthSessionService sessions = mock(StealthSessionService.class);
+        when(sessions.concealedPlayerIds()).thenReturn(ids);
+        return sessions;
+    }
+
+    private static Player player(boolean admin) {
+        Player player = mock(Player.class);
+        when(player.getUniqueId()).thenReturn(UUID.randomUUID());
+        when(player.hasPermission("spigotstealth.admin")).thenReturn(admin);
+        return player;
+    }
+
+    private static PlayerJoinEvent event(Player player) {
+        PlayerJoinEvent event = mock(PlayerJoinEvent.class);
+        when(event.getPlayer()).thenReturn(player);
+        return event;
+    }
+}

src/test/java/games/dmg/spigotstealth/StealthChatMaskerTest.java

@@ -0,0 +1,70 @@
+package games.dmg.spigotstealth;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import com.google.gson.JsonParser;
+import java.util.Set;
+import org.junit.jupiter.api.Test;
+
+class StealthChatMaskerTest {
+    private final StealthChatMasker masker = new StealthChatMasker(Set.of("Secret"));
+
+    @Test
+    void masksSenderAndRemovesIdentityMetadataWithoutChangingMessage() {
+        String input = """
+                {"translate":"chat.type.text","with":[
+                  {"text":"Secret","hoverEvent":{"action":"show_entity","contents":{"name":"Secret"}},
+                   "clickEvent":{"action":"suggest_command","value":"/msg Secret "}},
+                  {"text":"Secret says hello","clickEvent":{"action":"copy_to_clipboard","value":"Secret"}}]}
+                """;
+        var result = JsonParser.parseString(masker.maskAnnouncement(input)).getAsJsonObject();
+        var args = result.getAsJsonArray("with");
+        assertEquals(JsonParser.parseString("{\"text\":\"Anonymous\",\"obfuscated\":true,\"hoverEvent\":null,\"clickEvent\":null,\"insertion\":\"\"}"), args.get(0));
+        assertEquals(JsonParser.parseString(input).getAsJsonObject().getAsJsonArray("with").get(1), args.get(1));
+    }
+
+    @Test
+    void handlesPrivateMessagesAndAdvancementNamesOnly() {
+        for (String key : Set.of("commands.message.display.incoming", "commands.message.display.outgoing",
+                "chat.type.advancement.task", "chat.type.advancement.goal", "chat.type.advancement.challenge")) {
+            String input = "{\"translate\":\"" + key + "\",\"with\":[\"secret\",{\"text\":\"Secret\"}]}";
+            var args = JsonParser.parseString(masker.maskAnnouncement(input)).getAsJsonObject().getAsJsonArray("with");
+            assertEquals("Anonymous", args.get(0).getAsJsonObject().get("text").getAsString());
+            assertEquals("Secret", args.get(1).getAsJsonObject().get("text").getAsString());
+        }
+    }
+
+    @Test
+    void doesNotTraverseMessageBodyEvenWhenItContainsChatTranslations() {
+        String input = """
+                {"translate":"chat.type.text","with":["Ordinary",
+                  {"translate":"chat.type.text","with":["Secret","body"]}]}
+                """;
+        assertEquals(input, masker.maskAnnouncement(input));
+    }
+
+    @Test
+    void handlesNestedAnnouncementsButNotPlainTextOrUnknownTranslations() {
+        assertTrue(masker.maskAnnouncement("{\"text\":\"\",\"extra\":[{\"translate\":\"chat.type.text\",\"with\":[\"Secret\",\"hello\"]}]}").contains("Anonymous"));
+        for (String input : Set.of("{\"text\":\"Secret: hello\"}", "{\"translate\":\"custom\",\"with\":[\"Secret\"]}", "not json")) {
+            assertEquals(input, masker.maskAnnouncement(input));
+        }
+    }
+
+    @Test
+    void removesInheritedActionsFromArrayParent() {
+        String json = """
+                [{"text":"","hover_event":{"action":"show_text","value":"Secret"}},
+                 {"translate":"chat.type.text","with":["Secret","hello"]}]
+                """;
+        assertFalse(masker.maskAnnouncement(json).contains("Secret"));
+    }
+
+    @Test
+    void recognizesSplitNamesAndMasksWholeNameComponent() {
+        String name = "{\"text\":\"Sec\",\"extra\":[{\"text\":\"ret\"}],\"insertion\":\"Secret\"}";
+        assertTrue(masker.maskDisplayName(name).contains("Anonymous"));
+        assertFalse(masker.maskDisplayName(name).contains("Secret"));
+        assertEquals("\"NotSecret\"", masker.maskDisplayName("\"NotSecret\""));
+    }
+}

src/test/java/games/dmg/spigotstealth/StealthSessionListenerTest.java

@@ -62,8 +62,9 @@ class StealthSessionListenerTest {
             QualifyingInvisibilityService progression = new QualifyingInvisibilityService(
                     manager, Duration.ofHours(8), System::nanoTime, ignored -> { });
             IdentityPresentation presentation = mock(IdentityPresentation.class);
+            StealthSessionService sessions = new StealthSessionService(manager, progression);
             StealthSessionListener listener = new StealthSessionListener(
-                    new StealthSessionService(manager, progression), presentation, "Stealth active");
+                    sessions, presentation, "Stealth active");
             Player player = player(playerId);
             PlayerJoinEvent event = mock(PlayerJoinEvent.class);
             when(event.getPlayer()).thenReturn(player);
@@ -73,6 +74,10 @@ class StealthSessionListenerTest {
             verify(event).setJoinMessage(null);
             verify(presentation).conceal(player);
             verify(player).sendMessage("Stealth active");
+            Player admin = player(UUID.randomUUID());
+            when(admin.hasPermission("spigotstealth.admin")).thenReturn(true);
+            new StealthAdminJoinListener(sessions, () -> java.util.List.of(player, admin)).onJoin(event);
+            verify(admin).sendMessage("[Stealth] An invisible player joined. 1 player is now invisible. Use /stealthadmin list to see who.");
         }
     }