Add MC tab complete (incomplete, only 1.12.2 works)

proxy/src/main/java/com/velocitypowered/proxy/command/CommandManager.java

@@ -5,10 +5,7 @@ import com.google.common.collect.ImmutableList;
 import com.velocitypowered.api.command.CommandExecutor;
 import com.velocitypowered.api.command.CommandInvoker;
 
-import java.util.Arrays;
+import java.util.*;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
 import java.util.stream.Collectors;
 
 public class CommandManager {
@@ -49,30 +46,30 @@ public class CommandManager {
         }
     }
 
-    public List<String> offerSuggestions(CommandInvoker invoker, String cmdLine) {
+    public Optional<List<String>> offerSuggestions(CommandInvoker invoker, String cmdLine) {
         Preconditions.checkNotNull(invoker, "invoker");
         Preconditions.checkNotNull(cmdLine, "cmdLine");
 
         String[] split = cmdLine.split(" ", -1);
         if (split.length == 0) {
-            return ImmutableList.of();
+            return Optional.empty();
         }
 
         String command = split[0];
         if (split.length == 1) {
-            return executors.keySet().stream()
+            return Optional.of(executors.keySet().stream()
                     .filter(cmd -> cmd.regionMatches(true, 0, command, 0, command.length()))
-                    .collect(Collectors.toList());
+                    .collect(Collectors.toList()));
         }
 
         String[] actualArgs = Arrays.copyOfRange(split, 1, split.length);
         CommandExecutor executor = executors.get(command);
         if (executor == null) {
-            return ImmutableList.of();
+            return Optional.empty();
         }
 
         try {
-            return executor.suggest(invoker, actualArgs);
+            return Optional.of(executor.suggest(invoker, actualArgs));
         } catch (Exception e) {
             throw new RuntimeException("Unable to invoke suggestions for command " + command + " for " + invoker, e);
         }

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java

@@ -95,6 +95,34 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
             return;
         }
 
+        if (packet instanceof TabCompleteRequest) {
+            TabCompleteRequest req = (TabCompleteRequest) packet;
+            int lastSpace = req.getCommand().indexOf(' ');
+            if (!req.isAssumeCommand() && lastSpace != -1) {
+                String command = req.getCommand().substring(1);
+                try {
+                    Optional<List<String>> offers = VelocityServer.getServer().getCommandManager().offerSuggestions(player, command);
+                    if (offers.isPresent()) {
+                        TabCompleteResponse response = new TabCompleteResponse();
+                        response.setTransactionId(req.getTransactionId());
+                        response.setStart(lastSpace);
+                        response.setLength(req.getCommand().length() - lastSpace);
+                        for (String s : offers.get()) {
+                            response.getOffers().add(new TabCompleteResponse.Offer(s, null));
+                        }
+                        player.getConnection().write(response);
+                        return;
+                    }
+                } catch (Exception e) {
+                    logger.error("Unable to provide tab list completions for " + player.getUsername() + " for command '" + req.getCommand() + "'", e);
+                    TabCompleteResponse response = new TabCompleteResponse();
+                    response.setTransactionId(req.getTransactionId());
+                    player.getConnection().write(response);
+                    return;
+                }
+            }
+        }
+
         if (packet instanceof PluginMessage) {
             handleClientPluginMessage((PluginMessage) packet);
             return;

proxy/src/main/java/com/velocitypowered/proxy/console/VelocityConsole.java

@@ -7,6 +7,7 @@ import net.minecrell.terminalconsole.SimpleTerminalConsole;
 import org.jline.reader.*;
 
 import java.util.List;
+import java.util.Optional;
 
 public final class VelocityConsole extends SimpleTerminalConsole {
 
@@ -21,11 +22,13 @@ public final class VelocityConsole extends SimpleTerminalConsole {
         return super.buildReader(builder
                 .appName("Velocity")
                 .completer((reader, parsedLine, list) -> {
-                    List<String> offers = server.getCommandManager().offerSuggestions(server.getConsoleCommandInvoker(), parsedLine.line());
+                    Optional<List<String>> offers = server.getCommandManager().offerSuggestions(server.getConsoleCommandInvoker(), parsedLine.line());
-                    for (String offer : offers) {
+                    if (offers.isPresent()) {
+                        for (String offer : offers.get()) {
                             if (offer.isEmpty()) continue;
                             list.add(new Candidate(offer));
                         }
+                    }
                 })
         );
     }

proxy/src/main/java/com/velocitypowered/proxy/protocol/StateRegistry.java

@@ -32,6 +32,9 @@ public enum StateRegistry {
     },
     PLAY {
         {
+            SERVERBOUND.register(TabCompleteRequest.class, TabCompleteRequest::new,
+                    map(0x01, MINECRAFT_1_12_2),
+                    map(0x05, MINECRAFT_1_13));
             SERVERBOUND.register(Chat.class, Chat::new,
                     map(0x01, MINECRAFT_1_8),
                     map(0x02, MINECRAFT_1_9),
@@ -65,6 +68,9 @@ public enum StateRegistry {
                     map(0x0F, MINECRAFT_1_9),
                     map(0x0F, MINECRAFT_1_12),
                     map(0x0E, MINECRAFT_1_13));
+            CLIENTBOUND.register(TabCompleteResponse.class, TabCompleteResponse::new,
+                    map(0x0E, MINECRAFT_1_12),
+                    map(0x10, MINECRAFT_1_13));
             CLIENTBOUND.register(PluginMessage.class, PluginMessage::new,
                     map(0x3F, MINECRAFT_1_8),
                     map(0x18, MINECRAFT_1_9),

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/TabCompleteRequest.java

@@ -0,0 +1,97 @@
+package com.velocitypowered.proxy.protocol.packet;
+
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.ProtocolConstants;
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import io.netty.buffer.ByteBuf;
+
+import static com.velocitypowered.proxy.protocol.ProtocolConstants.MINECRAFT_1_13;
+
+public class TabCompleteRequest implements MinecraftPacket {
+    private int transactionId;
+    private String command;
+    private boolean assumeCommand;
+    private boolean hasPosition;
+    private long position;
+
+    public int getTransactionId() {
+        return transactionId;
+    }
+
+    public void setTransactionId(int transactionId) {
+        this.transactionId = transactionId;
+    }
+
+    public String getCommand() {
+        return command;
+    }
+
+    public void setCommand(String command) {
+        this.command = command;
+    }
+
+    public boolean isAssumeCommand() {
+        return assumeCommand;
+    }
+
+    public void setAssumeCommand(boolean assumeCommand) {
+        this.assumeCommand = assumeCommand;
+    }
+
+    public boolean isHasPosition() {
+        return hasPosition;
+    }
+
+    public void setHasPosition(boolean hasPosition) {
+        this.hasPosition = hasPosition;
+    }
+
+    public long getPosition() {
+        return position;
+    }
+
+    public void setPosition(long position) {
+        this.position = position;
+    }
+
+    @Override
+    public String toString() {
+        return "TabCompleteRequest{" +
+                "transactionId=" + transactionId +
+                ", command='" + command + '\'' +
+                ", assumeCommand=" + assumeCommand +
+                ", hasPosition=" + hasPosition +
+                ", position=" + position +
+                '}';
+    }
+
+    @Override
+    public void decode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+        if (protocolVersion >= MINECRAFT_1_13) {
+            this.transactionId = ProtocolUtils.readVarInt(buf);
+            this.command = ProtocolUtils.readString(buf);
+        } else {
+            this.command = ProtocolUtils.readString(buf);
+            this.assumeCommand = buf.readBoolean();
+            this.hasPosition = buf.readBoolean();
+            if (hasPosition) {
+                this.position = buf.readLong();
+            }
+        }
+    }
+
+    @Override
+    public void encode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+        if (protocolVersion >= MINECRAFT_1_13) {
+            ProtocolUtils.writeVarInt(buf, transactionId);
+            ProtocolUtils.writeString(buf, command);
+        } else {
+            ProtocolUtils.writeString(buf, command);
+            buf.writeBoolean(assumeCommand);
+            buf.writeBoolean(hasPosition);
+            if (hasPosition) {
+                buf.writeLong(position);
+            }
+        }
+    }
+}

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/TabCompleteResponse.java

@@ -0,0 +1,128 @@
+package com.velocitypowered.proxy.protocol.packet;
+
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.ProtocolConstants;
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import io.netty.buffer.ByteBuf;
+import net.kyori.text.Component;
+import net.kyori.text.TextComponent;
+import net.kyori.text.serializer.ComponentSerializers;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static com.velocitypowered.proxy.protocol.ProtocolConstants.MINECRAFT_1_13;
+
+public class TabCompleteResponse implements MinecraftPacket {
+    private int transactionId;
+    private int start;
+    private int length;
+    private final List<Offer> offers = new ArrayList<>();
+
+    public int getTransactionId() {
+        return transactionId;
+    }
+
+    public void setTransactionId(int transactionId) {
+        this.transactionId = transactionId;
+    }
+
+    public int getStart() {
+        return start;
+    }
+
+    public void setStart(int start) {
+        this.start = start;
+    }
+
+    public int getLength() {
+        return length;
+    }
+
+    public void setLength(int length) {
+        this.length = length;
+    }
+
+    public List<Offer> getOffers() {
+        return offers;
+    }
+
+    @Override
+    public String toString() {
+        return "TabCompleteResponse{" +
+                "transactionId=" + transactionId +
+                ", start=" + start +
+                ", length=" + length +
+                ", offers=" + offers +
+                '}';
+    }
+
+    @Override
+    public void decode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+        if (protocolVersion >= MINECRAFT_1_13) {
+            this.transactionId = ProtocolUtils.readVarInt(buf);
+            this.start = ProtocolUtils.readVarInt(buf);
+            this.length = ProtocolUtils.readVarInt(buf);
+            int offersAvailable = ProtocolUtils.readVarInt(buf);
+            for (int i = 0; i < offersAvailable; i++) {
+                String entry = ProtocolUtils.readString(buf);
+                Component component = buf.readBoolean() ? ComponentSerializers.JSON.deserialize(ProtocolUtils.readString(buf)) :
+                        null;
+                offers.add(new Offer(entry, component));
+            }
+        } else {
+            int offersAvailable = ProtocolUtils.readVarInt(buf);
+            for (int i = 0; i < offersAvailable; i++) {
+                offers.add(new Offer(ProtocolUtils.readString(buf), null));
+            }
+        }
+    }
+
+    @Override
+    public void encode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+        if (protocolVersion >= MINECRAFT_1_13) {
+            ProtocolUtils.writeVarInt(buf, transactionId);
+            ProtocolUtils.writeVarInt(buf, start);
+            ProtocolUtils.writeVarInt(buf, length);
+            ProtocolUtils.writeVarInt(buf, offers.size());
+            for (Offer offer : offers) {
+                ProtocolUtils.writeString(buf, offer.entry);
+                buf.writeBoolean(offer.tooltip != null);
+                if (offer.tooltip != null) {
+                    ProtocolUtils.writeString(buf, ComponentSerializers.JSON.serialize(offer.tooltip));
+                }
+            }
+        } else {
+            ProtocolUtils.writeVarInt(buf, offers.size());
+            for (Offer offer : offers) {
+                ProtocolUtils.writeString(buf, offer.entry);
+            }
+        }
+    }
+
+    public static class Offer {
+        private final String entry;
+        private final Component tooltip;
+
+        public Offer(String entry, Component tooltip) {
+            this.entry = entry;
+            this.tooltip = tooltip;
+        }
+
+        public String getEntry() {
+            return entry;
+        }
+
+        public Component getTooltip() {
+            return tooltip;
+        }
+
+        @Override
+        public String toString() {
+            return "Offer{" +
+                    "entry='" + entry + '\'' +
+                    ", tooltip=" + tooltip +
+                    '}';
+        }
+    }
+}