Add BossBar API (#213)

api/src/main/java/com/velocitypowered/api/proxy/ProxyServer.java

@@ -10,11 +10,15 @@ import com.velocitypowered.api.proxy.server.RegisteredServer;
 import com.velocitypowered.api.proxy.server.ServerInfo;
 import com.velocitypowered.api.scheduler.Scheduler;
 import com.velocitypowered.api.util.ProxyVersion;
+import com.velocitypowered.api.util.bossbar.BossBar;
+import com.velocitypowered.api.util.bossbar.BossBarColor;
+import com.velocitypowered.api.util.bossbar.BossBarOverlay;
 import java.net.InetSocketAddress;
 import java.util.Collection;
 import java.util.Optional;
 import java.util.UUID;
 import net.kyori.text.Component;
+import org.checkerframework.checker.nullness.qual.NonNull;
 
 /**
  * Provides an interface to a Minecraft server proxy.
@@ -173,4 +177,17 @@ public interface ProxyServer {
    * @return the proxy version
    */
   ProxyVersion getVersion();
+
+  /**
+   * Creates a new {@link BossBar}.
+   *
+   * @param title boss bar title
+   * @param color boss bar color
+   * @param overlay boss bar overlay
+   * @param progress boss bar progress
+   * @return a completely new and fresh boss bar
+   */
+  @NonNull
+  BossBar createBossBar(@NonNull Component title, @NonNull BossBarColor color,
+      @NonNull BossBarOverlay overlay, float progress);
 }

api/src/main/java/com/velocitypowered/api/util/bossbar/BossBar.java

@@ -0,0 +1,163 @@
+package com.velocitypowered.api.util.bossbar;
+
+import com.velocitypowered.api.proxy.Player;
+import java.util.Collection;
+import net.kyori.text.Component;
+import org.checkerframework.checker.nullness.qual.NonNull;
+
+/**
+ * Represents a boss bar, which can be send to a (group of) player(s).
+ * <b>Boss bars only work on 1.9 and above.</b>
+ */
+public interface BossBar {
+
+  /**
+   * Adds all specified players to this boss bar.
+   *
+   * @param players players
+   * @see #addPlayer(Player)
+   */
+  void addPlayers(Iterable<Player> players);
+
+  /**
+   * Adds player to this boss bar. This adds the player to the {@link #getPlayers()} and makes him
+   * see the boss bar.
+   *
+   * @param player the player you wish to add
+   */
+  void addPlayer(@NonNull Player player);
+
+  /**
+   * Removes player from this boss bar. This removes the player from {@link #getPlayers()} and makes
+   * him not see the boss bar.
+   *
+   * @param player the player you wish to remove
+   */
+  void removePlayer(@NonNull Player player);
+
+  /**
+   * Removes all specified players from this boss bar.
+   *
+   * @param players players
+   * @see #removePlayer(Player)
+   */
+  void removePlayers(Iterable<Player> players);
+
+  /**
+   * Removes all players, that see this boss bar.
+   *
+   * @see #removePlayer(Player)
+   */
+  void removeAllPlayers();
+
+  /**
+   * Gets the title of this boss bar.
+   *
+   * @return title
+   */
+  @NonNull
+  Component getTitle();
+
+  /**
+   * Sets a new title of the boss bar.
+   *
+   * @param title new title
+   */
+  void setTitle(@NonNull Component title);
+
+  /**
+   * Gets the boss bar's progress. In Minecraft, this is called 'health' of the boss bar.
+   *
+   * @return progress
+   */
+  float getProgress();
+
+  /**
+   * Sets a new progress of the boss bar. In Minecraft, this is called 'health' of the boss bar.
+   *
+   * @param progress a float between 0 and 1, representing boss bar's progress
+   * @throws IllegalArgumentException if the new progress is not between 0 and 1
+   */
+  void setProgress(float progress);
+
+  /**
+   * Returns a copy of the {@link Collection} of all {@link Player} added to the boss bar.
+   * <i>Can be empty.</i>
+   *
+   * @return players
+   */
+  Collection<Player> getPlayers();
+
+  /**
+   * Gets the color of the boss bar.
+   *
+   * @return boss bar color
+   */
+  @NonNull
+  BossBarColor getColor();
+
+  /**
+   * Sets a new color of the boss bar.
+   *
+   * @param color the color you wish the boss bar be displayed with
+   */
+  void setColor(@NonNull BossBarColor color);
+
+  /**
+   * Gets the overlay of the boss bar.
+   *
+   * @return boss bar overlay
+   */
+  @NonNull
+  BossBarOverlay getOverlay();
+
+  /**
+   * Sets a new overlay of the boss bar.
+   *
+   * @param overlay the overlay you wish the boss bar be displayed with
+   */
+  void setOverlay(@NonNull BossBarOverlay overlay);
+
+  /**
+   * Returns whenever this boss bar is visible to all added {@link #getPlayers()}. By default, it
+   * returns <code>true</code>.
+   *
+   * @return <code>true</code> if visible, otherwise <code>false</code>
+   */
+  boolean isVisible();
+
+  /**
+   * Sets a new visibility to the boss bar.
+   *
+   * @param visible boss bar visibility value
+   */
+  void setVisible(boolean visible);
+
+  /**
+   * Returns a copy of of the {@link Collection} of all {@link BossBarFlag}s added to the boss bar.
+   *
+   * @return flags
+   */
+  Collection<BossBarFlag> getFlags();
+
+  /**
+   * Adds new flags to the boss bar.
+   *
+   * @param flags the flags you wish to add
+   */
+  void addFlags(BossBarFlag... flags);
+
+  /**
+   * Removes flag from the boss bar.
+   *
+   * @param flag the flag you wish to remove
+   */
+  void removeFlag(BossBarFlag flag);
+
+  /**
+   * Removes flags from the boss bar.
+   *
+   * @param flags the flags you wish to remove
+   */
+  void removeFlags(BossBarFlag... flags);
+}

api/src/main/java/com/velocitypowered/api/util/bossbar/BossBarColor.java

@@ -0,0 +1,14 @@
+package com.velocitypowered.api.util.bossbar;
+
+/**
+ * Represents a color of a {@link BossBar}.
+ */
+public enum BossBarColor {
+  PINK,
+  BLUE,
+  RED,
+  GREEN,
+  YELLOW,
+  PURPLE,
+  WHITE;
+}

api/src/main/java/com/velocitypowered/api/util/bossbar/BossBarFlag.java

@@ -0,0 +1,10 @@
+package com.velocitypowered.api.util.bossbar;
+
+/**
+ * Represents any {@link BossBar}'s flags.
+ */
+public enum BossBarFlag {
+  DARKEN_SKY,
+  DRAGON_BAR,
+  CREATE_FOG
+}

api/src/main/java/com/velocitypowered/api/util/bossbar/BossBarOverlay.java

@@ -0,0 +1,12 @@
+package com.velocitypowered.api.util.bossbar;
+
+/**
+ * Represents a overlay of a {@link BossBar}.
+ */
+public enum BossBarOverlay {
+  SOLID,
+  SEGMENTED_6,
+  SEGMENTED_10,
+  SEGMENTED_12,
+  SEGMENTED_20
+}

proxy/src/main/java/com/velocitypowered/proxy/VelocityServer.java

@@ -17,6 +17,9 @@ import com.velocitypowered.api.proxy.server.ServerInfo;
 import com.velocitypowered.api.util.Favicon;
 import com.velocitypowered.api.util.GameProfile;
 import com.velocitypowered.api.util.ProxyVersion;
+import com.velocitypowered.api.util.bossbar.BossBar;
+import com.velocitypowered.api.util.bossbar.BossBarColor;
+import com.velocitypowered.api.util.bossbar.BossBarOverlay;
 import com.velocitypowered.proxy.command.GlistCommand;
 import com.velocitypowered.proxy.command.ServerCommand;
 import com.velocitypowered.proxy.command.ShutdownCommand;
@@ -38,6 +41,7 @@ import com.velocitypowered.proxy.server.ServerMap;
 import com.velocitypowered.proxy.util.AddressUtil;
 import com.velocitypowered.proxy.util.EncryptionUtils;
 import com.velocitypowered.proxy.util.VelocityChannelRegistrar;
+import com.velocitypowered.proxy.util.bossbar.VelocityBossBar;
 import com.velocitypowered.proxy.util.ratelimit.Ratelimiter;
 import com.velocitypowered.proxy.util.ratelimit.Ratelimiters;
 import io.netty.bootstrap.Bootstrap;
@@ -66,6 +70,7 @@ import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.checkerframework.checker.nullness.qual.EnsuresNonNull;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.NonNull;
 import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 
 public class VelocityServer implements ProxyServer {
@@ -133,6 +138,15 @@ public class VelocityServer implements ProxyServer {
     return new ProxyVersion(implName, implVendor, implVersion);
   }
 
+  @Override
+  public @NonNull BossBar createBossBar(
+      @NonNull Component title,
+      @NonNull BossBarColor color,
+      @NonNull BossBarOverlay overlay,
+      float progress) {
+    return new VelocityBossBar(title, color, overlay, progress);
+  }
+
   @Override
   public VelocityCommandManager getCommandManager() {
     return commandManager;

proxy/src/main/java/com/velocitypowered/proxy/util/bossbar/VelocityBossBar.java

@@ -0,0 +1,276 @@
+package com.velocitypowered.proxy.util.bossbar;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import com.google.common.collect.ImmutableList;
+import com.velocitypowered.api.network.ProtocolVersion;
+import com.velocitypowered.api.proxy.Player;
+import com.velocitypowered.api.util.bossbar.BossBarColor;
+import com.velocitypowered.api.util.bossbar.BossBarFlag;
+import com.velocitypowered.api.util.bossbar.BossBarOverlay;
+import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.packet.BossBar;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.EnumSet;
+import java.util.List;
+import java.util.Set;
+import java.util.UUID;
+import net.kyori.text.Component;
+import net.kyori.text.serializer.gson.GsonComponentSerializer;
+import org.checkerframework.checker.nullness.qual.NonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+public class VelocityBossBar implements com.velocitypowered.api.util.bossbar.BossBar {
+
+  private final List<Player> players;
+  private final Set<BossBarFlag> flags;
+  private final UUID uuid;
+  private boolean visible;
+  private Component title;
+  private float progress;
+  private BossBarColor color;
+  private BossBarOverlay overlay;
+
+  /**
+   * Creates a new boss bar.
+   * @param title the title for the bar
+   * @param color the color of the bar
+   * @param overlay the overlay to use
+   * @param progress the progress of the bar
+   */
+  public VelocityBossBar(
+      Component title, BossBarColor color, BossBarOverlay overlay, float progress) {
+    this.title = checkNotNull(title, "title");
+    this.color = checkNotNull(color, "color");
+    this.overlay = checkNotNull(overlay, "overlay");
+    this.progress = progress;
+    if (progress > 1 || progress < 0) {
+      throw new IllegalArgumentException("Progress not between 0 and 1");
+    }
+    this.uuid = UUID.randomUUID();
+    visible = true;
+    players = new ArrayList<>();
+    flags = EnumSet.noneOf(BossBarFlag.class);
+  }
+
+  @Override
+  public void addPlayers(@NonNull Iterable<Player> players) {
+    checkNotNull(players, "players");
+    for (Player player : players) {
+      addPlayer(player);
+    }
+  }
+
+  @Override
+  public void addPlayer(@NonNull Player player) {
+    checkNotNull(player, "player");
+    if (!players.contains(player)) {
+      players.add(player);
+    }
+    if (player.isActive() && visible) {
+      sendPacket(player, addPacket());
+    }
+  }
+
+  @Override
+  public void removePlayer(@NonNull Player player) {
+    checkNotNull(player, "player");
+    players.remove(player);
+    if (player.isActive()) {
+      sendPacket(player, removePacket());
+    }
+  }
+
+  @Override
+  public void removePlayers(@NonNull Iterable<Player> players) {
+    checkNotNull(players, "players");
+    for (Player player : players) {
+      removePlayer(player);
+    }
+  }
+
+  @Override
+  public void removeAllPlayers() {
+    removePlayers(ImmutableList.copyOf(players));
+  }
+
+  @Override
+  public @NonNull Component getTitle() {
+    return title;
+  }
+
+  @Override
+  public void setTitle(@NonNull Component title) {
+    this.title = checkNotNull(title, "title");
+    if (visible) {
+      BossBar bar = new BossBar();
+      bar.setUuid(uuid);
+      bar.setAction(BossBar.UPDATE_NAME);
+      bar.setName(GsonComponentSerializer.INSTANCE.serialize(title));
+      sendToAffected(bar);
+    }
+  }
+
+  @Override
+  public float getProgress() {
+    return progress;
+  }
+
+  @Override
+  public void setProgress(float progress) {
+    if (progress > 1 || progress < 0) {
+      throw new IllegalArgumentException("Progress should be between 0 and 1");
+    }
+    this.progress = progress;
+    if (visible) {
+      BossBar bar = new BossBar();
+      bar.setUuid(uuid);
+      bar.setAction(BossBar.UPDATE_PERCENT);
+      bar.setPercent(progress);
+      sendToAffected(bar);
+    }
+  }
+
+  @Override
+  public @Nullable Collection<Player> getPlayers() {
+    return ImmutableList.copyOf(players);
+  }
+
+  @Override
+  public @NonNull BossBarColor getColor() {
+    return color;
+  }
+
+  @Override
+  public void setColor(@NonNull BossBarColor color) {
+    this.color = checkNotNull(color, "color");
+    if (visible) {
+      sendDivisions(color, overlay);
+    }
+  }
+
+  @Override
+  public @NonNull BossBarOverlay getOverlay() {
+    return overlay;
+  }
+
+  @Override
+  public void setOverlay(@NonNull BossBarOverlay overlay) {
+    this.overlay = checkNotNull(overlay, "overlay");
+    if (visible) {
+      sendDivisions(color, overlay);
+    }
+  }
+
+  private void sendDivisions(BossBarColor color, BossBarOverlay overlay) {
+    BossBar bar = new BossBar();
+    bar.setUuid(uuid);
+    bar.setAction(BossBar.UPDATE_STYLE);
+    bar.setColor(color.ordinal());
+    bar.setOverlay(overlay.ordinal());
+    sendToAffected(bar);
+  }
+
+  @Override
+  public boolean isVisible() {
+    return visible;
+  }
+
+  @Override
+  public void setVisible(boolean visible) {
+    boolean previous = this.visible;
+    if (previous && !visible) {
+      // The bar is being hidden
+      sendToAffected(removePacket());
+    } else if (!previous && visible) {
+      // The bar is being shown
+      sendToAffected(addPacket());
+    }
+    this.visible = visible;
+  }
+
+  @Override
+  public Collection<BossBarFlag> getFlags() {
+    return ImmutableList.copyOf(flags);
+  }
+
+  @Override
+  public void addFlags(BossBarFlag... flags) {
+    if (this.flags.addAll(Arrays.asList(flags)) && visible) {
+      sendToAffected(updateFlags());
+    }
+  }
+
+  @Override
+  public void removeFlag(BossBarFlag flag) {
+    checkNotNull(flag, "flag");
+    if (this.flags.remove(flag) && visible) {
+      sendToAffected(updateFlags());
+    }
+  }
+
+  @Override
+  public void removeFlags(BossBarFlag... flags) {
+    if (this.flags.removeAll(Arrays.asList(flags)) && visible) {
+      sendToAffected(updateFlags());
+    }
+  }
+
+  private short serializeFlags() {
+    short flagMask = 0x0;
+    if (flags.contains(BossBarFlag.DARKEN_SKY)) {
+      flagMask |= 0x1;
+    }
+    if (flags.contains(BossBarFlag.DRAGON_BAR)) {
+      flagMask |= 0x2;
+    }
+    if (flags.contains(BossBarFlag.CREATE_FOG)) {
+      flagMask |= 0x4;
+    }
+    return flagMask;
+  }
+
+  private BossBar addPacket() {
+    BossBar bossBar = new BossBar();
+    bossBar.setUuid(uuid);
+    bossBar.setAction(BossBar.ADD);
+    bossBar.setName(GsonComponentSerializer.INSTANCE.serialize(title));
+    bossBar.setColor(color.ordinal());
+    bossBar.setOverlay(overlay.ordinal());
+    bossBar.setPercent(progress);
+    bossBar.setFlags(serializeFlags());
+    return bossBar;
+  }
+
+  private BossBar removePacket() {
+    BossBar bossBar = new BossBar();
+    bossBar.setUuid(uuid);
+    bossBar.setAction(BossBar.REMOVE);
+    return bossBar;
+  }
+
+  private BossBar updateFlags() {
+    BossBar bossBar = new BossBar();
+    bossBar.setUuid(uuid);
+    bossBar.setAction(BossBar.UPDATE_PROPERTIES);
+    bossBar.setFlags(serializeFlags());
+    return bossBar;
+  }
+
+  private void sendToAffected(MinecraftPacket packet) {
+    for (Player player : players) {
+      if (player.isActive() && player.getProtocolVersion().getProtocol()
+          >= ProtocolVersion.MINECRAFT_1_9.getProtocol()) {
+        sendPacket(player, packet);
+      }
+    }
+  }
+
+  private void sendPacket(Player player, MinecraftPacket packet) {
+    ConnectedPlayer connected = (ConnectedPlayer) player;
+    connected.getMinecraftConnection().write(packet);
+  }
+}