Add basic tab completion support.

This commit adds support for basic tab completion for most of the commands that take arguments. Some completions are somewhat intelligent, e.g. `/ma join` which only lists enabled and "functional" arenas that the given player is permitted to use. Others are just kinda dumb, e.g. `/ma enable` which indiscriminately lists all arenas.

Closes #405

changelog.md

@@ -12,6 +12,7 @@ These changes will (most likely) be included in the next version.
 
 ## [Unreleased]
 - Extended and upgraded potions are now supported in the item syntax by prepending `long_` or `strong_` to the data portion of a potion item (e.g. `potion:strong_instant_heal:1` will yield a Potion of Healing II). Check the wiki for details.
+- MobArena now has basic tab completion support for most of the commands that take arguments.
 - Tridents and crossbows are now considered weapons with regards to the `unbreakable-weapons` flag. All class items that have durability now have their unbreakable flag set to true unless the `unbreakable-weapons` and/or `unbreakable-armor` flags are set to `false`.
 - Leaderboards now work again on servers running Minecraft 1.14+.
 - Class chests (non-linked) now work again on servers running Minecraft 1.14+.

src/main/java/com/garbagemule/MobArena/commands/Command.java

@@ -2,6 +2,10 @@ package com.garbagemule.MobArena.commands;
 
 import com.garbagemule.MobArena.framework.ArenaMaster;
 import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+
+import java.util.Collections;
+import java.util.List;
 
 public interface Command
 {
@@ -25,4 +29,16 @@ public interface Command
      * command handler should print the usage message to the sender
      */
     boolean execute(ArenaMaster am, CommandSender sender, String... args);
+
+    /**
+     * Tab complete the given arguments.
+     *
+     * @param am an ArenaMaster instance
+     * @param player the sender
+     * @param args array of arguments
+     * @return a list of possible completions, or null
+     */
+    default List<String> tab(ArenaMaster am, Player player, String... args) {
+        return Collections.emptyList();
+    }
 }

src/main/java/com/garbagemule/MobArena/commands/CommandHandler.java

@@ -34,16 +34,20 @@ import com.garbagemule.MobArena.framework.ArenaMaster;
 import org.bukkit.ChatColor;
 import org.bukkit.command.CommandExecutor;
 import org.bukkit.command.CommandSender;
+import org.bukkit.command.TabCompleter;
 import org.bukkit.conversations.Conversable;
+import org.bukkit.entity.Player;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.stream.Collectors;
 
-public class CommandHandler implements CommandExecutor
+public class CommandHandler implements CommandExecutor, TabCompleter
 {
     private MobArena plugin;
     private Messenger fallbackMessenger;
@@ -237,6 +241,60 @@ public class CommandHandler implements CommandExecutor
         }
     }
     
+    @Override
+    public List<String> onTabComplete(CommandSender sender, org.bukkit.command.Command bcmd, String alias, String[] args) {
+        // Only players can tab complete
+        if (!(sender instanceof Player)) {
+            return null;
+        }
+        Player player = (Player) sender;
+
+        // If the player is in a convo (Setup Mode), bail
+        if (player.isConversing()) {
+            return null;
+        }
+
+        // Grab the base argument.
+        String base = (args.length > 0 ? args[0] : "").toLowerCase();
+
+        // If there's no base argument, show it all
+        if (base.equals("")) {
+            return commands.values()
+                .stream()
+                .map(cmd -> cmd.getClass().getAnnotation(CommandInfo.class))
+                .filter(info -> info != null && player.hasPermission(info.permission()))
+                .map(CommandInfo::name)
+                .sorted()
+                .collect(Collectors.toList());
+        }
+
+        // Reloads are terminal
+        if (base.equals("reload") || (base.equals("config") && args.length > 1 && args[1].equals("reload"))) {
+            return Collections.emptyList();
+        }
+
+        // If we only have the base, terminate
+        if (args.length == 1) {
+            return commands.values().stream()
+                .map(cmd -> cmd.getClass().getAnnotation(CommandInfo.class))
+                .filter(info -> info.name().startsWith(base))
+                .map(CommandInfo::name)
+                .sorted()
+                .collect(Collectors.toList());
+        }
+
+        // Otherwise, find the command
+        List<Command> matches = getMatchingCommands(base);
+        if (matches.size() != 1) {
+            return Collections.emptyList();
+        }
+
+        // And pass completion
+        Command command = matches.get(0);
+        String[] params = trimFirstArg(args);
+        return command.tab(plugin.getArenaMaster(), player, params);
+    }
+
     /**
      * Register all the commands directly.
      * This could also be done with a somewhat dirty classloader/resource reader

src/main/java/com/garbagemule/MobArena/commands/admin/DisableCommand.java

@@ -7,6 +7,11 @@ import com.garbagemule.MobArena.framework.Arena;
 import com.garbagemule.MobArena.framework.ArenaMaster;
 import org.bukkit.ChatColor;
 import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
 
 @CommandInfo(
     name    = "disable",
@@ -50,4 +55,20 @@ public class DisableCommand implements Command
         arena.getPlugin().saveConfig();
         arena.getGlobalMessenger().tell(sender, "Arena '" + arena.configName() + "' " + ChatColor.RED + "disabled");
     }
+
+    @Override
+    public List<String> tab(ArenaMaster am, Player player, String... args) {
+        if (args.length > 1) {
+            return Collections.emptyList();
+        }
+
+        String prefix = args[0].toLowerCase();
+
+        List<Arena> arenas = am.getArenas();
+
+        return arenas.stream()
+            .filter(arena -> arena.configName().toLowerCase().startsWith(prefix))
+            .map(Arena::configName)
+            .collect(Collectors.toList());
+    }
 }

src/main/java/com/garbagemule/MobArena/commands/admin/EnableCommand.java

@@ -7,6 +7,11 @@ import com.garbagemule.MobArena.framework.Arena;
 import com.garbagemule.MobArena.framework.ArenaMaster;
 import org.bukkit.ChatColor;
 import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
 
 @CommandInfo(
     name    = "enable",
@@ -50,4 +55,20 @@ public class EnableCommand implements Command
         arena.getPlugin().saveConfig();
         arena.getGlobalMessenger().tell(sender, "Arena '" + arena.configName() + "' " + ChatColor.GREEN + "enabled");
     }
+
+    @Override
+    public List<String> tab(ArenaMaster am, Player player, String... args) {
+        if (args.length > 1) {
+            return Collections.emptyList();
+        }
+
+        String prefix = args[0].toLowerCase();
+
+        List<Arena> arenas = am.getArenas();
+
+        return arenas.stream()
+            .filter(arena -> arena.configName().toLowerCase().startsWith(prefix))
+            .map(Arena::configName)
+            .collect(Collectors.toList());
+    }
 }

src/main/java/com/garbagemule/MobArena/commands/admin/ForceCommand.java

@@ -6,6 +6,12 @@ import com.garbagemule.MobArena.commands.CommandInfo;
 import com.garbagemule.MobArena.framework.Arena;
 import com.garbagemule.MobArena.framework.ArenaMaster;
 import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
 
 @CommandInfo(
     name    = "force",
@@ -82,4 +88,38 @@ public class ForceCommand implements Command
         }
         return false;
     }
+
+    @Override
+    public List<String> tab(ArenaMaster am, Player player, String... args) {
+        if (args.length > 2) {
+            return Collections.emptyList();
+        }
+
+        if (args.length == 1) {
+            String prefix = args[0].toLowerCase();
+            List<String> result = new ArrayList<>(2);
+            if ("end".startsWith(prefix)) {
+                result.add("end");
+            }
+            if ("start".startsWith(prefix)) {
+                result.add("start");
+            }
+            return result;
+        }
+
+        if (!args[0].equals("end") && !args[0].equals("start")) {
+            return Collections.emptyList();
+        }
+
+        boolean start = args[0].equals("start");
+        String prefix = args[1].toLowerCase();
+
+        List<Arena> arenas = am.getArenas();
+
+        return arenas.stream()
+            .filter(arena -> arena.configName().toLowerCase().startsWith(prefix))
+            .filter(arena -> start != arena.isRunning())
+            .map(Arena::configName)
+            .collect(Collectors.toList());
+    }
 }

src/main/java/com/garbagemule/MobArena/commands/admin/KickCommand.java

@@ -7,6 +7,10 @@ import com.garbagemule.MobArena.framework.ArenaMaster;
 import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
 
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
 @CommandInfo(
     name    = "kick",
     pattern = "kick|kcik",
@@ -36,4 +40,20 @@ public class KickCommand implements Command
         am.getGlobalMessenger().tell(bp, "You were kicked by " + sender.getName() + ".");
         return true;
     }
+
+    @Override
+    public List<String> tab(ArenaMaster am, Player player, String... args) {
+        if (args.length > 1) {
+            return Collections.emptyList();
+        }
+
+        String prefix = args[0].toLowerCase();
+
+        List<Player> players = am.getAllPlayers();
+
+        return players.stream()
+            .filter(p -> p.getDisplayName().toLowerCase().startsWith(prefix))
+            .map(Player::getDisplayName)
+            .collect(Collectors.toList());
+    }
 }

src/main/java/com/garbagemule/MobArena/commands/admin/RestoreCommand.java

@@ -7,6 +7,11 @@ import com.garbagemule.MobArena.util.inventory.InventoryManager;
 import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
 
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
 @CommandInfo(
     name    = "restore",
     pattern = "restore",
@@ -38,4 +43,20 @@ public class RestoreCommand implements Command
         }
         return true;
     }
+
+    @Override
+    public List<String> tab(ArenaMaster am, Player player, String... args) {
+        if (args.length > 1) {
+            return Collections.emptyList();
+        }
+
+        String prefix = args[0].toLowerCase();
+
+        Collection<? extends Player> players = am.getPlugin().getServer().getOnlinePlayers();
+
+        return players.stream()
+            .filter(p -> p.getDisplayName().toLowerCase().startsWith(prefix))
+            .map(Player::getDisplayName)
+            .collect(Collectors.toList());
+    }
 }

src/main/java/com/garbagemule/MobArena/commands/setup/ClassChestCommand.java

@@ -13,7 +13,11 @@ import org.bukkit.block.Block;
 import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
 
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
 import java.util.Set;
+import java.util.stream.Collectors;
 
 @CommandInfo(
     name    = "classchest",
@@ -58,4 +62,20 @@ public class ClassChestCommand implements Command {
         am.loadClasses();
         return true;
     }
+
+    @Override
+    public List<String> tab(ArenaMaster am, Player player, String... args) {
+        if (args.length > 1) {
+            return Collections.emptyList();
+        }
+
+        String prefix = args[0].toLowerCase();
+
+        Collection<ArenaClass> classes = am.getClasses().values();
+
+        return classes.stream()
+            .filter(cls -> cls.getConfigName().toLowerCase().startsWith(prefix))
+            .map(ArenaClass::getConfigName)
+            .collect(Collectors.toList());
+    }
 }

src/main/java/com/garbagemule/MobArena/commands/setup/EditArenaCommand.java

@@ -6,6 +6,11 @@ import com.garbagemule.MobArena.framework.Arena;
 import com.garbagemule.MobArena.framework.ArenaMaster;
 import org.bukkit.ChatColor;
 import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
 
 @CommandInfo(
     name    = "editarena",
@@ -52,4 +57,20 @@ public class EditArenaCommand implements Command
         if (arena.inEditMode()) am.getGlobalMessenger().tell(sender, "Remember to turn it back off after editing!");
         return true;
     }
+
+    @Override
+    public List<String> tab(ArenaMaster am, Player player, String... args) {
+        if (args.length > 1) {
+            return Collections.emptyList();
+        }
+
+        String prefix = args[0].toLowerCase();
+
+        List<Arena> arenas = am.getArenas();
+
+        return arenas.stream()
+            .filter(arena -> arena.configName().toLowerCase().startsWith(prefix))
+            .map(Arena::configName)
+            .collect(Collectors.toList());
+    }
 }

src/main/java/com/garbagemule/MobArena/commands/setup/RemoveArenaCommand.java

@@ -5,6 +5,11 @@ import com.garbagemule.MobArena.commands.CommandInfo;
 import com.garbagemule.MobArena.framework.Arena;
 import com.garbagemule.MobArena.framework.ArenaMaster;
 import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
 
 @CommandInfo(
     name    = "removearena",
@@ -34,4 +39,20 @@ public class RemoveArenaCommand implements Command
         am.getGlobalMessenger().tell(sender, "Arena '" + arena.configName() + "' deleted.");
         return true;
     }
+
+    @Override
+    public List<String> tab(ArenaMaster am, Player player, String... args) {
+        if (args.length > 1) {
+            return Collections.emptyList();
+        }
+
+        String prefix = args[0].toLowerCase();
+
+        List<Arena> arenas = am.getArenas();
+
+        return arenas.stream()
+            .filter(arena -> arena.configName().toLowerCase().startsWith(prefix))
+            .map(Arena::configName)
+            .collect(Collectors.toList());
+    }
 }

src/main/java/com/garbagemule/MobArena/commands/setup/SettingCommand.java

@@ -6,8 +6,13 @@ import com.garbagemule.MobArena.framework.Arena;
 import com.garbagemule.MobArena.framework.ArenaMaster;
 import org.bukkit.ChatColor;
 import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
 
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 @CommandInfo(
     name    = "setting",
@@ -95,4 +100,37 @@ public class SettingCommand implements Command {
         am.getGlobalMessenger().tell(sender, buffy.toString());
         return true;
     }
+
+    @Override
+    public List<String> tab(ArenaMaster am, Player player, String... args) {
+        if (args.length > 2) {
+            return Collections.emptyList();
+        }
+
+        List<Arena> arenas = am.getArenas();
+
+        if (args.length == 1) {
+            String prefix = args[0].toLowerCase();
+
+            return arenas.stream()
+                .filter(arena -> arena.configName().toLowerCase().startsWith(prefix))
+                .filter(arena -> !arena.isRunning())
+                .map(Arena::configName)
+                .collect(Collectors.toList());
+        }
+
+        Arena arena = am.getArenaWithName(args[0]);
+        if (arena == null) {
+            return Collections.emptyList();
+        }
+
+        String prefix = args[1].toLowerCase();
+
+        Collection<String> settings = arena.getSettings().getValues(false).keySet();
+
+        return settings.stream()
+            .filter(s -> s.toLowerCase().startsWith(prefix))
+            .sorted()
+            .collect(Collectors.toList());
+    }
 }

src/main/java/com/garbagemule/MobArena/commands/setup/SetupCommand.java

@@ -38,7 +38,9 @@ import org.bukkit.inventory.meta.ItemMeta;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
+import java.util.stream.Collectors;
 
 @CommandInfo(
     name    = "setup",
@@ -88,6 +90,22 @@ public class SetupCommand implements Command, Listener {
         return true;
     }
 
+    @Override
+    public List<String> tab(ArenaMaster am, Player player, String... args) {
+        if (args.length > 1) {
+            return Collections.emptyList();
+        }
+
+        String prefix = args[0].toLowerCase();
+
+        List<Arena> arenas = am.getArenas();
+
+        return arenas.stream()
+            .filter(arena -> arena.configName().toLowerCase().startsWith(prefix))
+            .map(Arena::configName)
+            .collect(Collectors.toList());
+    }
+
     /**
      * The internal Setup class has three roles; it is the prompt and the
      * abandon listener for the Conversation initiated by the setup command,

src/main/java/com/garbagemule/MobArena/commands/user/JoinCommand.java

@@ -10,6 +10,10 @@ import com.garbagemule.MobArena.framework.ArenaMaster;
 import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
 
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
 @CommandInfo(
     name    = "join",
     pattern = "j|jo.*|j.*n",
@@ -77,4 +81,22 @@ public class JoinCommand implements Command
             arena.playerJoin(player, player.getLocation());
         }
     }
+
+    @Override
+    public List<String> tab(ArenaMaster am, Player player, String... args) {
+        if (args.length > 1) {
+            return Collections.emptyList();
+        }
+
+        String prefix = args[0].toLowerCase();
+
+        List<Arena> arenas = am.getPermittedArenas(player);
+
+        return arenas.stream()
+            .filter(Arena::isEnabled)
+            .filter(arena -> arena.configName().toLowerCase().startsWith(prefix))
+            .filter(arena -> arena.getRegion().isSetup())
+            .map(Arena::configName)
+            .collect(Collectors.toList());
+    }
 }

src/main/java/com/garbagemule/MobArena/commands/user/PickClassCommand.java

@@ -13,6 +13,11 @@ import com.garbagemule.MobArena.util.ClassChests;
 import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
 
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
 @CommandInfo(
     name    = "class",
     pattern = "(pick)?class",
@@ -101,4 +106,21 @@ public class PickClassCommand implements Command
         }
         return true;
     }
+
+    @Override
+    public List<String> tab(ArenaMaster am, Player player, String... args) {
+        if (args.length > 1) {
+            return Collections.emptyList();
+        }
+
+        String prefix = args[0].toLowerCase();
+
+        Collection<ArenaClass> classes = am.getClasses().values();
+
+        return classes.stream()
+            .filter(cls -> cls.getConfigName().toLowerCase().startsWith(prefix))
+            .filter(cls -> cls.hasPermission(player))
+            .map(ArenaClass::getConfigName)
+            .collect(Collectors.toList());
+    }
 }

src/main/java/com/garbagemule/MobArena/commands/user/SpecCommand.java

@@ -10,6 +10,10 @@ import com.garbagemule.MobArena.framework.ArenaMaster;
 import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
 
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
 @CommandInfo(
     name    = "spec",
     pattern = "s|spec.*",
@@ -71,4 +75,22 @@ public class SpecCommand implements Command
             arena.playerSpec(player, player.getLocation());
         }
     }
+
+    @Override
+    public List<String> tab(ArenaMaster am, Player player, String... args) {
+        if (args.length > 1) {
+            return Collections.emptyList();
+        }
+
+        String prefix = args[0].toLowerCase();
+
+        List<Arena> arenas = am.getPermittedArenas(player);
+
+        return arenas.stream()
+            .filter(Arena::isEnabled)
+            .filter(arena -> arena.configName().toLowerCase().startsWith(prefix))
+            .filter(arena -> arena.getRegion().isSetup())
+            .map(Arena::configName)
+            .collect(Collectors.toList());
+    }
 }