Mostly implements the join and create commands

src/main/java/net/knarcraft/dropper/Dropper.java

@@ -6,6 +6,7 @@ import net.knarcraft.dropper.command.CreateArenaCommand;
 import net.knarcraft.dropper.command.EditArenaCommand;
 import net.knarcraft.dropper.command.EditArenaTabCompleter;
 import net.knarcraft.dropper.command.JoinArenaCommand;
+import net.knarcraft.dropper.command.JoinArenaTabCompleter;
 import net.knarcraft.dropper.command.LeaveArenaCommand;
 import net.knarcraft.dropper.command.ListArenaCommand;
 import net.knarcraft.dropper.command.RemoveArenaCommand;
@@ -84,7 +85,7 @@ public final class Dropper extends JavaPlugin {
 
         registerCommand("droppercreate", new CreateArenaCommand(), null);
         registerCommand("dropperlist", new ListArenaCommand(), null);
-        registerCommand("dropperjoin", new JoinArenaCommand(), null);
+        registerCommand("dropperjoin", new JoinArenaCommand(), new JoinArenaTabCompleter());
         registerCommand("dropperleave", new LeaveArenaCommand(), null);
         registerCommand("dropperedit", new EditArenaCommand(), new EditArenaTabCompleter());
         registerCommand("dropperremove", new RemoveArenaCommand(), null);

src/main/java/net/knarcraft/dropper/command/CreateArenaCommand.java

@@ -1,8 +1,12 @@
 package net.knarcraft.dropper.command;
 
+import net.knarcraft.dropper.Dropper;
+import net.knarcraft.dropper.arena.DropperArena;
+import net.knarcraft.dropper.util.ArenaStorageHelper;
 import org.bukkit.command.Command;
 import org.bukkit.command.CommandExecutor;
 import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
 import org.jetbrains.annotations.NotNull;
 
 /**
@@ -12,13 +16,33 @@ public class CreateArenaCommand implements CommandExecutor {
 
     @Override
     public boolean onCommand(@NotNull CommandSender commandSender, @NotNull Command command, @NotNull String s,
-                             @NotNull String[] strings) {
+                             @NotNull String[] arguments) {
-        //TODO: Make sure the console cannot run this
+        if (!(commandSender instanceof Player player)) {
-        //TODO: Make sure the arena name isn't a duplicate and doesn't contain any unwanted characters
+            commandSender.sendMessage("This command must be used by a player");
-        //TODO: Create a new arena
+            return false;
-        //TODO: Register the new arena in the arena handler
+        }
-        //TODO: Tell the user of success
+
-        return false;
+        // Abort if no name was specified
+        if (arguments.length < 1) {
+            return false;
+        }
+
+        String arenaName = arguments[0];
+        String sanitized = ArenaStorageHelper.sanitizeArenaName(arenaName);
+
+        for (DropperArena arena : Dropper.getInstance().getArenaHandler().getArenas()) {
+            if (sanitized.equals(ArenaStorageHelper.sanitizeArenaName(arena.getArenaName()))) {
+                commandSender.sendMessage("There already exists a dropper arena with that name!");
+                return false;
+            }
+        }
+
+        //TODO: Make sure the arena name doesn't contain any unwanted characters
+
+        DropperArena arena = new DropperArena(arenaName, player.getLocation());
+        Dropper.getInstance().getArenaHandler().addArena(arena);
+        commandSender.sendMessage("The arena was successfully created!");
+        return true;
     }
 
 }

src/main/java/net/knarcraft/dropper/command/JoinArenaCommand.java

@@ -5,6 +5,7 @@ import net.knarcraft.dropper.arena.DropperArena;
 import net.knarcraft.dropper.arena.DropperArenaPlayerRegistry;
 import net.knarcraft.dropper.arena.DropperArenaSession;
 import net.knarcraft.dropper.property.ArenaGameMode;
+import net.knarcraft.dropper.util.ArenaStorageHelper;
 import net.knarcraft.dropper.util.PlayerTeleporter;
 import org.bukkit.command.Command;
 import org.bukkit.command.CommandExecutor;
@@ -37,10 +38,10 @@ public class JoinArenaCommand implements CommandExecutor {
         }
 
         // Make sure the arena exists
-        String arenaName = arguments[0].trim();
+        String arenaName = ArenaStorageHelper.sanitizeArenaName(arguments[0]);
         DropperArena specifiedArena = null;
         for (DropperArena arena : Dropper.getInstance().getArenaHandler().getArenas()) {
-            if (arena.getArenaName().equalsIgnoreCase(arenaName)) {
+            if (ArenaStorageHelper.sanitizeArenaName(arena.getArenaName()).equals(arenaName)) {
                 specifiedArena = arena;
                 break;
             }

src/main/java/net/knarcraft/dropper/command/JoinArenaTabCompleter.java

@@ -0,0 +1,39 @@
+package net.knarcraft.dropper.command;
+
+import net.knarcraft.dropper.Dropper;
+import net.knarcraft.dropper.arena.DropperArena;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.TabCompleter;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * The tab-completer for the join command
+ */
+public class JoinArenaTabCompleter implements TabCompleter {
+
+    @Override
+    public @Nullable List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command,
+                                                @NotNull String label, @NotNull String[] args) {
+        if (args.length == 1) {
+            List<String> arenaNames = new ArrayList<>();
+            for (DropperArena dropperArena : Dropper.getInstance().getArenaHandler().getArenas()) {
+                arenaNames.add(dropperArena.getArenaName());
+            }
+            return arenaNames;
+        } else if (args.length == 2) {
+            List<String> gameModes = new ArrayList<>();
+            gameModes.add("default");
+            gameModes.add("deaths");
+            gameModes.add("time");
+            return gameModes;
+        } else {
+            return new ArrayList<>();
+        }
+    }
+
+}