Update display names for team players after team updates

Resolves #1912

connector/src/main/java/org/geysermc/connector/entity/Entity.java

@@ -41,7 +41,6 @@ import it.unimi.dsi.fastutil.longs.LongOpenHashSet;
 import lombok.Getter;
 import lombok.Setter;
 import net.kyori.adventure.text.Component;
-import org.geysermc.connector.entity.living.ArmorStandEntity;
 import org.geysermc.connector.entity.player.PlayerEntity;
 import org.geysermc.connector.entity.type.EntityType;
 import org.geysermc.connector.network.session.GeyserSession;
@@ -256,10 +255,7 @@ public class Entity {
                 setAir((int) entityMetadata.getValue());
                 break;
             case 2: // custom name
-                if (entityMetadata.getValue() instanceof Component message) {
+                setDisplayName(session, (Component) entityMetadata.getValue());
-                    // Always translate even if it's a TextMessage since there could be translatable parameters
-                    metadata.put(EntityData.NAMETAG, MessageTranslator.convertMessage(message, session.getLocale()));
-                }
                 break;
             case 3: // is custom name visible
                 if (!this.is(PlayerEntity.class))
@@ -310,6 +306,21 @@ public class Entity {
         return false;
     }
 
+    /**
+     * @return the translated string display
+     */
+    protected String setDisplayName(GeyserSession session, Component name) {
+        if (name != null) {
+            String displayName = MessageTranslator.convertMessage(name, session.getLocale());
+            metadata.put(EntityData.NAMETAG, displayName);
+            return displayName;
+        } else if (!metadata.getString(EntityData.NAMETAG).isEmpty()) {
+            // Clear nametag
+            metadata.put(EntityData.NAMETAG, "");
+        }
+        return null;
+    }
+
     /**
      * Set the height and width of the entity's bounding box
      */

connector/src/main/java/org/geysermc/connector/entity/player/PlayerEntity.java

@@ -29,6 +29,7 @@ import com.github.steveice10.mc.auth.data.GameProfile;
 import com.github.steveice10.mc.protocol.data.game.entity.metadata.EntityMetadata;
 import com.github.steveice10.mc.protocol.data.game.entity.metadata.Pose;
 import com.github.steveice10.mc.protocol.data.game.scoreboard.ScoreboardPosition;
+import com.github.steveice10.mc.protocol.data.game.scoreboard.TeamColor;
 import com.github.steveice10.opennbt.tag.builtin.CompoundTag;
 import com.nukkitx.math.vector.Vector3f;
 import com.nukkitx.math.vector.Vector3i;
@@ -39,9 +40,11 @@ import com.nukkitx.protocol.bedrock.data.entity.EntityData;
 import com.nukkitx.protocol.bedrock.data.entity.EntityFlag;
 import com.nukkitx.protocol.bedrock.data.entity.EntityLinkData;
 import com.nukkitx.protocol.bedrock.packet.*;
+import lombok.AccessLevel;
 import lombok.Getter;
 import lombok.Setter;
 import net.kyori.adventure.text.Component;
+import org.geysermc.connector.common.ChatColor;
 import org.geysermc.connector.entity.Entity;
 import org.geysermc.connector.entity.LivingEntity;
 import org.geysermc.connector.entity.living.animal.tameable.ParrotEntity;
@@ -53,6 +56,7 @@ import org.geysermc.connector.scoreboard.Score;
 import org.geysermc.connector.scoreboard.Team;
 import org.geysermc.connector.scoreboard.UpdateType;
 
+import javax.annotation.Nullable;
 import java.util.Collections;
 import java.util.UUID;
 import java.util.concurrent.TimeUnit;
@@ -64,6 +68,9 @@ public class PlayerEntity extends LivingEntity {
     private String username;
     private boolean playerList = true;  // Player is in the player list
 
+    @Getter(AccessLevel.NONE)
+    private String displayName;
+
     /**
      * Saves the parrot currently on the player's left shoulder; otherwise null
      */
@@ -79,6 +86,7 @@ public class PlayerEntity extends LivingEntity {
         profile = gameProfile;
         uuid = gameProfile.getId();
         username = gameProfile.getName();
+        displayName = username;
 
         // For the OptionalPack, set all bits as invisible by default as this matches Java Edition behavior
         metadata.put(EntityData.MARK_VARIANT, 0xff);
@@ -240,23 +248,6 @@ public class PlayerEntity extends LivingEntity {
     public void updateBedrockMetadata(EntityMetadata entityMetadata, GeyserSession session) {
         super.updateBedrockMetadata(entityMetadata, session);
 
-        if (entityMetadata.getId() == 2) {
-            String username = this.username;
-            Component name = (Component) entityMetadata.getValue();
-            if (name != null) {
-                username = MessageTranslator.convertMessage(name);
-            }
-            Team team = session.getWorldCache().getScoreboard().getTeamFor(username);
-            if (team != null) {
-                String displayName = "";
-                if (team.isVisibleFor(session.getPlayerEntity().getUsername())) {
-                    displayName = MessageTranslator.toChatColor(team.getColor()) + username;
-                    displayName = team.getCurrentData().getDisplayName(displayName);
-                }
-                metadata.put(EntityData.NAMETAG, displayName);
-            }
-        }
-
         // Extra hearts - is not metadata but an attribute on Bedrock
         if (entityMetadata.getId() == 15) {
             UpdateAttributesPacket attributesPacket = new UpdateAttributesPacket();
@@ -319,6 +310,65 @@ public class PlayerEntity extends LivingEntity {
         }
     }
 
+    @Override
+    protected String setDisplayName(GeyserSession session, Component name) {
+        String displayName = super.setDisplayName(session, name);
+        this.displayName = displayName != null ? displayName : username;
+        // Update if we know this player has a team
+        updateDisplayName(session, null, false);
+
+        return this.displayName;
+    }
+
+    //todo this will become common entity logic once UUID support is implemented for them
+    /**
+     * @param useGivenTeam even if there is no team, update the username in the entity metadata anyway, and don't look for a team
+     */
+    public void updateDisplayName(GeyserSession session, @Nullable Team team, boolean useGivenTeam) {
+        if (team == null && !useGivenTeam) {
+            // Only search for the team if we are not supposed to use the given team
+            // If the given team is null, this is intentional that we are being removed from the team
+            team = session.getWorldCache().getScoreboard().getTeamFor(username);
+        }
+
+        boolean needsUpdate;
+        String newDisplayName = this.displayName;
+        if (team != null) {
+            if (team.isVisibleFor(session.getPlayerEntity().getUsername())) {
+                TeamColor color = team.getColor();
+                String chatColor;
+                if (color == TeamColor.NONE) {
+                    chatColor = ChatColor.RESET;
+                } else {
+                    chatColor = MessageTranslator.toChatColor(color);
+                }
+                // We have to emulate what modern Java text already does for us and add the color to each section
+                String prefix = team.getCurrentData().getPrefix();
+                String suffix = team.getCurrentData().getSuffix();
+                newDisplayName = chatColor + prefix + chatColor + this.displayName + chatColor + suffix;
+            } else {
+                // The name is not visible to the session player; clear name
+                newDisplayName = "";
+            }
+            needsUpdate = useGivenTeam && !newDisplayName.equals(metadata.getString(EntityData.NAMETAG, null));
+            metadata.put(EntityData.NAMETAG, newDisplayName);
+        } else if (useGivenTeam) {
+            // The name has reset, if it was previously something else
+            needsUpdate = !newDisplayName.equals(metadata.getString(EntityData.NAMETAG));
+            metadata.put(EntityData.NAMETAG, this.displayName);
+        } else {
+            needsUpdate = false;
+        }
+
+        if (needsUpdate) {
+            // Update the metadata as it won't be updated later
+            SetEntityDataPacket packet = new SetEntityDataPacket();
+            packet.getMetadata().put(EntityData.NAMETAG, newDisplayName);
+            packet.setRuntimeEntityId(geyserId);
+            session.sendUpstreamPacket(packet);
+        }
+    }
+
     @Override
     protected void setDimensions(Pose pose) {
         float height;

connector/src/main/java/org/geysermc/connector/network/session/cache/EntityCache.java

@@ -25,13 +25,16 @@
 
 package org.geysermc.connector.network.session.cache;
 
-import it.unimi.dsi.fastutil.longs.*;
+import it.unimi.dsi.fastutil.longs.Long2LongMap;
+import it.unimi.dsi.fastutil.longs.Long2LongOpenHashMap;
+import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
+import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
 import it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap;
 import it.unimi.dsi.fastutil.objects.ObjectArrayList;
 import it.unimi.dsi.fastutil.objects.ObjectOpenHashSet;
 import lombok.Getter;
-import org.geysermc.connector.entity.Tickable;
 import org.geysermc.connector.entity.Entity;
+import org.geysermc.connector.entity.Tickable;
 import org.geysermc.connector.entity.player.PlayerEntity;
 import org.geysermc.connector.network.session.GeyserSession;
 

connector/src/main/java/org/geysermc/connector/network/translators/chat/MessageTranslator.java

@@ -28,8 +28,6 @@ package org.geysermc.connector.network.translators.chat;
 import com.github.steveice10.mc.protocol.data.DefaultComponentSerializer;
 import com.github.steveice10.mc.protocol.data.game.scoreboard.TeamColor;
 import net.kyori.adventure.text.Component;
-import net.kyori.adventure.text.format.NamedTextColor;
-import net.kyori.adventure.text.format.TextDecoration;
 import net.kyori.adventure.text.renderer.TranslatableComponentRenderer;
 import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer;
 import net.kyori.adventure.text.serializer.gson.legacyimpl.NBTLegacyHoverEventSerializer;
@@ -38,9 +36,10 @@ import org.geysermc.connector.GeyserConnector;
 import org.geysermc.connector.network.session.GeyserSession;
 import org.geysermc.connector.utils.LanguageUtils;
 
-import java.util.HashMap;
+import java.util.EnumMap;
 import java.util.Locale;
 import java.util.Map;
+import java.util.regex.Pattern;
 
 public class MessageTranslator {
 
@@ -54,7 +53,7 @@ public class MessageTranslator {
             .build();
 
     // Store team colors for player names
-    private static final Map<TeamColor, TextDecoration> TEAM_FORMATS = new HashMap<>();
+    private static final Map<TeamColor, String> TEAM_COLORS = new EnumMap<>(TeamColor.class);
 
     // Legacy formatting character
     private static final String BASE = "\u00a7";
@@ -62,11 +61,36 @@ public class MessageTranslator {
     // Reset character
     private static final String RESET = BASE + "r";
 
+    /* Various regexes to fix formatting for Bedrock's specifications */
+    private static final Pattern STRIKETHROUGH_UNDERLINE = Pattern.compile("\u00a7[mn]");
+    private static final Pattern COLOR_CHARACTERS = Pattern.compile("\u00a7([0-9a-f])");
+    private static final Pattern DOUBLE_RESET = Pattern.compile("\u00a7r\u00a7r");
+
     static {
-        TEAM_FORMATS.put(TeamColor.OBFUSCATED, TextDecoration.OBFUSCATED);
+        TEAM_COLORS.put(TeamColor.NONE, "");
-        TEAM_FORMATS.put(TeamColor.BOLD, TextDecoration.BOLD);
+
-        TEAM_FORMATS.put(TeamColor.STRIKETHROUGH, TextDecoration.STRIKETHROUGH);
+        TEAM_COLORS.put(TeamColor.BLACK, BASE + "0");
-        TEAM_FORMATS.put(TeamColor.ITALIC, TextDecoration.ITALIC);
+        TEAM_COLORS.put(TeamColor.DARK_BLUE, BASE + "1");
+        TEAM_COLORS.put(TeamColor.DARK_GREEN, BASE + "2");
+        TEAM_COLORS.put(TeamColor.DARK_AQUA, BASE + "3");
+        TEAM_COLORS.put(TeamColor.DARK_RED, BASE + "4");
+        TEAM_COLORS.put(TeamColor.DARK_PURPLE, BASE + "5");
+        TEAM_COLORS.put(TeamColor.GOLD, BASE + "6");
+        TEAM_COLORS.put(TeamColor.GRAY, BASE + "7");
+        TEAM_COLORS.put(TeamColor.DARK_GRAY, BASE + "8");
+        TEAM_COLORS.put(TeamColor.BLUE, BASE + "9");
+        TEAM_COLORS.put(TeamColor.GREEN, BASE + "a");
+        TEAM_COLORS.put(TeamColor.AQUA, BASE + "b");
+        TEAM_COLORS.put(TeamColor.RED, BASE + "c");
+        TEAM_COLORS.put(TeamColor.LIGHT_PURPLE, BASE + "d");
+        TEAM_COLORS.put(TeamColor.YELLOW, BASE + "e");
+        TEAM_COLORS.put(TeamColor.WHITE, BASE + "f");
+
+        // Formats, not colors
+        TEAM_COLORS.put(TeamColor.OBFUSCATED, BASE + "k");
+        TEAM_COLORS.put(TeamColor.BOLD, BASE + "l");
+        TEAM_COLORS.put(TeamColor.STRIKETHROUGH, BASE + "m");
+        TEAM_COLORS.put(TeamColor.ITALIC, BASE + "o");
 
         // Tell MCProtocolLib to use our serializer
         DefaultComponentSerializer.set(GSON_SERIALIZER);
@@ -88,12 +112,12 @@ public class MessageTranslator {
             String legacy = LegacyComponentSerializer.legacySection().serialize(message);
 
             // Strip strikethrough and underline as they are not supported on bedrock
-            legacy = legacy.replaceAll("\u00a7[mn]", "");
+            legacy = STRIKETHROUGH_UNDERLINE.matcher(legacy).replaceAll("");
 
             // Make color codes reset formatting like Java
             // See https://minecraft.gamepedia.com/Formatting_codes#Usage
-            legacy = legacy.replaceAll("\u00a7([0-9a-f])", "\u00a7r\u00a7$1");
+            legacy = COLOR_CHARACTERS.matcher(legacy).replaceAll("\u00a7r\u00a7$1");
-            legacy = legacy.replaceAll("\u00a7r\u00a7r", "\u00a7r");
+            legacy = DOUBLE_RESET.matcher(legacy).replaceAll("\u00a7r");
 
             return legacy;
         } catch (Exception e) {
@@ -158,84 +182,6 @@ public class MessageTranslator {
         return GSON_SERIALIZER.serialize(component);
     }
 
-    /**
-     * Convert a {@link NamedTextColor} into a string for inserting into messages
-     *
-     * @param color {@link NamedTextColor} to convert
-     * @return The converted color string
-     */
-    private static String getColor(NamedTextColor color) {
-        StringBuilder str = new StringBuilder(BASE);
-        if (color.equals(NamedTextColor.BLACK)) {
-            str.append("0");
-        } else if (color.equals(NamedTextColor.DARK_BLUE)) {
-            str.append("1");
-        } else if (color.equals(NamedTextColor.DARK_GREEN)) {
-            str.append("2");
-        } else if (color.equals(NamedTextColor.DARK_AQUA)) {
-            str.append("3");
-        } else if (color.equals(NamedTextColor.DARK_RED)) {
-            str.append("4");
-        } else if (color.equals(NamedTextColor.DARK_PURPLE)) {
-            str.append("5");
-        } else if (color.equals(NamedTextColor.GOLD)) {
-            str.append("6");
-        } else if (color.equals(NamedTextColor.GRAY)) {
-            str.append("7");
-        } else if (color.equals(NamedTextColor.DARK_GRAY)) {
-            str.append("8");
-        } else if (color.equals(NamedTextColor.BLUE)) {
-            str.append("9");
-        } else if (color.equals(NamedTextColor.GREEN)) {
-            str.append("a");
-        } else if (color.equals(NamedTextColor.AQUA)) {
-            str.append("b");
-        } else if (color.equals(NamedTextColor.RED)) {
-            str.append("c");
-        } else if (color.equals(NamedTextColor.LIGHT_PURPLE)) {
-            str.append("d");
-        } else if (color.equals(NamedTextColor.YELLOW)) {
-            str.append("e");
-        } else if (color.equals(NamedTextColor.WHITE)) {
-            str.append("f");
-        } else {
-            return "";
-        }
-
-        return str.toString();
-    }
-
-    /**
-     * Convert a {@link TextDecoration} into a string for inserting into messages
-     *
-     * @param format {@link TextDecoration} to convert
-     * @return The converted chat formatting string
-     */
-    private static String getFormat(TextDecoration format) {
-        StringBuilder str = new StringBuilder(BASE);
-        switch (format) {
-            case OBFUSCATED:
-                str.append("k");
-                break;
-            case BOLD:
-                str.append("l");
-                break;
-            case STRIKETHROUGH:
-                str.append("m");
-                break;
-            case UNDERLINED:
-                str.append("n");
-                break;
-            case ITALIC:
-                str.append("o");
-                break;
-            default:
-                return "";
-        }
-
-        return str.toString();
-    }
-
     /**
      * Convert a team color to a chat color
      *
@@ -243,16 +189,7 @@ public class MessageTranslator {
      * @return The chat color character
      */
     public static String toChatColor(TeamColor teamColor) {
-        if (teamColor.equals(TeamColor.NONE)) {
+        return TEAM_COLORS.getOrDefault(teamColor, "");
-            return "";
-        }
-
-        NamedTextColor textColor = NamedTextColor.NAMES.value(teamColor.name().toLowerCase());
-        if (textColor != null) {
-            return getColor(textColor);
-        }
-
-        return getFormat(TEAM_FORMATS.get(teamColor));
     }
 
     /**

connector/src/main/java/org/geysermc/connector/network/translators/java/scoreboard/JavaTeamTranslator.java

@@ -25,7 +25,9 @@
 
 package org.geysermc.connector.network.translators.java.scoreboard;
 
+import com.github.steveice10.mc.protocol.data.game.scoreboard.NameTagVisibility;
 import com.github.steveice10.mc.protocol.data.game.scoreboard.TeamAction;
+import com.github.steveice10.mc.protocol.data.game.scoreboard.TeamColor;
 import com.github.steveice10.mc.protocol.packet.ingame.server.scoreboard.ServerTeamPacket;
 import org.geysermc.connector.GeyserConnector;
 import org.geysermc.connector.GeyserLogger;
@@ -37,9 +39,9 @@ import org.geysermc.connector.scoreboard.Scoreboard;
 import org.geysermc.connector.scoreboard.ScoreboardUpdater;
 import org.geysermc.connector.scoreboard.Team;
 import org.geysermc.connector.scoreboard.UpdateType;
-import org.geysermc.connector.utils.LanguageUtils;
 
 import java.util.Arrays;
+import java.util.Set;
 
 @Translator(packet = ServerTeamPacket.class)
 public class JavaTeamTranslator extends PacketTranslator<ServerTeamPacket> {
@@ -60,48 +62,77 @@ public class JavaTeamTranslator extends PacketTranslator<ServerTeamPacket> {
         Scoreboard scoreboard = session.getWorldCache().getScoreboard();
         Team team = scoreboard.getTeam(packet.getTeamName());
         switch (packet.getAction()) {
-            case CREATE ->
+            case CREATE -> {
-                    scoreboard.registerNewTeam(packet.getTeamName(), packet.getPlayers())
+                team = scoreboard.registerNewTeam(packet.getTeamName(), packet.getPlayers())
                         .setName(MessageTranslator.convertMessage(packet.getDisplayName()))
                         .setColor(packet.getColor())
                         .setNameTagVisibility(packet.getNameTagVisibility())
                         .setPrefix(MessageTranslator.convertMessage(packet.getPrefix(), session.getLocale()))
                         .setSuffix(MessageTranslator.convertMessage(packet.getSuffix(), session.getLocale()));
+
+                if (packet.getPlayers().length != 0) {
+                    if ((team.getNameTagVisibility() != NameTagVisibility.ALWAYS && !team.isVisibleFor(session.getPlayerEntity().getUsername()))
+                            || team.getColor() != TeamColor.NONE
+                            || !team.getCurrentData().getPrefix().isEmpty()
+                            || !team.getCurrentData().getSuffix().isEmpty()) {
+                        // Something is here that would modify entity names
+                        scoreboard.updateEntityNames(team, true);
+                    }
+                }
+            }
             case UPDATE -> {
                 if (team == null) {
-                    logger.debug(LanguageUtils.getLocaleStringLog(
+                    if (logger.isDebug()) {
-                            "geyser.network.translator.team.failed_not_registered",
+                        logger.debug("Error while translating Team Packet " + packet.getAction()
-                            packet.getAction(), packet.getTeamName()
+                                + "! Scoreboard Team " + packet.getTeamName() + " is not registered."
-                    ));
+                        );
+                    }
                     return;
                 }
 
+                TeamColor oldColor = team.getColor();
+                NameTagVisibility oldVisibility = team.getNameTagVisibility();
+                String oldPrefix = team.getCurrentData().getPrefix();
+                String oldSuffix = team.getCurrentData().getSuffix();
+
                 team.setName(MessageTranslator.convertMessage(packet.getDisplayName()))
                         .setColor(packet.getColor())
                         .setNameTagVisibility(packet.getNameTagVisibility())
                         .setPrefix(MessageTranslator.convertMessage(packet.getPrefix(), session.getLocale()))
                         .setSuffix(MessageTranslator.convertMessage(packet.getSuffix(), session.getLocale()))
                         .setUpdateType(UpdateType.UPDATE);
+
+                if (oldVisibility != team.getNameTagVisibility()
+                        || oldColor != team.getColor()
+                        || !oldPrefix.equals(team.getCurrentData().getPrefix())
+                        || !oldSuffix.equals(team.getCurrentData().getSuffix())) {
+                    // Update entities attached to this team as something about their nameplates have changed
+                    scoreboard.updateEntityNames(team, false);
+                }
             }
             case ADD_PLAYER -> {
                 if (team == null) {
-                    logger.debug(LanguageUtils.getLocaleStringLog(
+                    if (logger.isDebug()) {
-                            "geyser.network.translator.team.failed_not_registered",
+                        logger.debug("Error while translating Team Packet " + packet.getAction()
-                            packet.getAction(), packet.getTeamName()
+                                + "! Scoreboard Team " + packet.getTeamName() + " is not registered."
-                    ));
+                        );
+                    }
                     return;
                 }
-                team.addEntities(packet.getPlayers());
+                Set<String> added = team.addEntities(packet.getPlayers());
+                scoreboard.updateEntityNames(team, added, true);
             }
             case REMOVE_PLAYER -> {
                 if (team == null) {
-                    logger.debug(LanguageUtils.getLocaleStringLog(
+                    if (logger.isDebug()) {
-                            "geyser.network.translator.team.failed_not_registered",
+                        logger.debug("Error while translating Team Packet " + packet.getAction()
-                            packet.getAction(), packet.getTeamName()
+                                + "! Scoreboard Team " + packet.getTeamName() + " is not registered."
-                    ));
+                        );
+                    }
                     return;
                 }
-                team.removeEntities(packet.getPlayers());
+                Set<String> removed = team.removeEntities(packet.getPlayers());
+                scoreboard.updateEntityNames(null, removed, true);
             }
             case REMOVE -> scoreboard.removeTeam(packet.getTeamName());
         }

connector/src/main/java/org/geysermc/connector/scoreboard/Scoreboard.java

@@ -33,10 +33,12 @@ import com.nukkitx.protocol.bedrock.packet.SetScorePacket;
 import lombok.Getter;
 import org.geysermc.connector.GeyserConnector;
 import org.geysermc.connector.GeyserLogger;
+import org.geysermc.connector.entity.Entity;
 import org.geysermc.connector.entity.player.PlayerEntity;
 import org.geysermc.connector.network.session.GeyserSession;
 import org.geysermc.connector.utils.LanguageUtils;
 
+import javax.annotation.Nullable;
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicLong;
@@ -127,7 +129,8 @@ public final class Scoreboard {
             return team;
         }
 
-        team = new Team(this, teamName).addEntities(players);
+        team = new Team(this, teamName);
+        team.addEntities(players);
         teams.put(teamName, team);
         return team;
     }
@@ -155,6 +158,9 @@ public final class Scoreboard {
         Team remove = teams.remove(teamName);
         if (remove != null) {
             remove.setUpdateType(REMOVE);
+            // We need to use the direct entities list here, so #refreshSessionPlayerDisplays also updates accordingly
+            // With the player's lack of a team in visibility checks
+            updateEntityNames(remove, remove.getEntities(), true);
         }
     }
 
@@ -326,4 +332,47 @@ public final class Scoreboard {
         }
         return null;
     }
+
+    /**
+     * Updates the display names of all entities in a given team.
+     * @param teamChange the players have either joined or left the team. Used for optimizations when just the display name updated.
+     */
+    public void updateEntityNames(Team team, boolean teamChange) {
+        Set<String> names = new HashSet<>(team.getEntities());
+        updateEntityNames(team, names, teamChange);
+    }
+
+    /**
+     * Updates the display name of a set of entities within a given team. The team may also be null if the set is being removed
+     * from a team.
+     */
+    public void updateEntityNames(@Nullable Team team, Set<String> names, boolean teamChange) {
+        if (names.remove(session.getPlayerEntity().getUsername()) && teamChange) {
+            // If the player's team changed, then other entities' teams may modify their visibility based on team status
+            refreshSessionPlayerDisplays();
+        }
+        if (!names.isEmpty()) {
+            for (Entity entity : session.getEntityCache().getEntities().values()) {
+                // This more complex logic is for the future to iterate over all entities, not just players
+                if (entity instanceof PlayerEntity player && names.remove(player.getUsername())) {
+                    player.updateDisplayName(session, team, true);
+                    if (names.isEmpty()) {
+                        break;
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * If the team's player was refreshed, then we need to go through every entity and check...
+     */
+    private void refreshSessionPlayerDisplays() {
+        for (Entity entity : session.getEntityCache().getEntities().values()) {
+            if (entity instanceof PlayerEntity player) {
+                Team playerTeam = session.getWorldCache().getScoreboard().getTeamFor(player.getUsername());
+                player.updateDisplayName(session, playerTeam, true);
+            }
+        }
+    }
 }

connector/src/main/java/org/geysermc/connector/scoreboard/Team.java

@@ -33,8 +33,7 @@ import lombok.Getter;
 import lombok.Setter;
 import lombok.experimental.Accessors;
 
-import java.util.ArrayList;
+import java.util.HashSet;
-import java.util.List;
 import java.util.Set;
 
 @Getter
@@ -43,7 +42,7 @@ public final class Team {
     private final Scoreboard scoreboard;
     private final String id;
 
-    @Getter(AccessLevel.NONE)
+    @Getter(AccessLevel.PACKAGE)
     private final Set<String> entities;
     @Setter private NameTagVisibility nameTagVisibility;
     @Setter private TeamColor color;
@@ -60,16 +59,16 @@ public final class Team {
         entities = new ObjectOpenHashSet<>();
     }
 
-    public Team addEntities(String... names) {
+    public Set<String> addEntities(String... names) {
-        List<String> added = new ArrayList<>();
+        Set<String> added = new HashSet<>();
         for (String name : names) {
             if (entities.add(name)) {
                 added.add(name);
             }
         }
 
-        if (added.size() == 0) {
+        if (added.isEmpty()) {
-            return this;
+            return added;
         }
         // we don't have to change the updateType,
         // because the scores itself need updating, not the team
@@ -81,14 +80,22 @@ public final class Team {
                 }
             }
         }
-        return this;
+
+        return added;
     }
 
-    public void removeEntities(String... names) {
+    /**
+     * @return all removed entities from this team
+     */
+    public Set<String> removeEntities(String... names) {
+        Set<String> removed = new HashSet<>();
         for (String name : names) {
-            entities.remove(name);
+            if (entities.remove(name)) {
+                removed.add(name);
             }
         }
+        return removed;
+    }
 
     public boolean hasEntity(String name) {
         return entities.contains(name);
@@ -172,7 +179,11 @@ public final class Team {
 
     public boolean isVisibleFor(String entity) {
         return switch (nameTagVisibility) {
-            case HIDE_FOR_OTHER_TEAMS -> hasEntity(entity);
+            case HIDE_FOR_OTHER_TEAMS -> {
+                // Player must be in a team in order for HIDE_FOR_OTHER_TEAMS to be triggered
+                Team team = scoreboard.getTeamFor(entity);
+                yield team == null || team == this;
+            }
             case HIDE_FOR_OWN_TEAM -> !hasEntity(entity);
             case ALWAYS -> true;
             case NEVER -> false;