Adds /whohas command

server/src/main/java/dev/plex/command/impl/WhoHasCMD.java

@@ -0,0 +1,53 @@
+package dev.plex.command.impl;
+
+import com.destroystokyo.paper.MaterialSetTag;
+import com.google.common.collect.ImmutableList;
+import dev.plex.command.PlexCommand;
+import dev.plex.command.annotation.CommandParameters;
+import dev.plex.command.annotation.CommandPermissions;
+import net.kyori.adventure.text.Component;
+import net.kyori.adventure.text.JoinConfiguration;
+import net.kyori.adventure.text.TextComponent;
+import org.bukkit.Bukkit;
+import org.bukkit.Material;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Arrays;
+import java.util.List;
+
+@CommandPermissions(permission = "plex.whohas")
+@CommandParameters(name = "whohas", description = "Returns a list of players with a specific item in their inventory.", usage = "/<command> <material>", aliases = "wh")
+public class WhoHasCMD extends PlexCommand
+{
+    @Override
+    protected Component execute(@NotNull CommandSender sender, @Nullable Player playerSender, @NotNull String[] args)
+    {
+        if (args.length == 0)
+        {
+            return usage();
+        }
+
+        final Material material = Material.getMaterial(args[0].toUpperCase());
+
+        if (material == null)
+        {
+            return messageComponent("materialNotFound", args[0]);
+        }
+
+        final List<TextComponent> players = Bukkit.getOnlinePlayers().stream().filter(player ->
+                player.getInventory().contains(material)).map(player -> Component.text(player.getName())).toList();
+
+        return players.isEmpty() ? messageComponent("nobodyHasThatMaterial") :
+                messageComponent("playersWithMaterial", Component.text(material.name()),
+                        Component.join(JoinConfiguration.commas(true), players));
+    }
+
+    @Override
+    public @NotNull List<String> tabComplete(@NotNull CommandSender sender, @NotNull String alias, @NotNull String[] args) throws IllegalArgumentException
+    {
+        return args.length == 1 && silentCheckPermission(sender, "plex.whohas") ? Arrays.stream(Material.values()).map(Enum::name).toList() : ImmutableList.of();
+    }
+}

server/src/main/resources/messages.yml

@@ -204,3 +204,9 @@ removedOwnLoginMessage: "<gray>Your login message has been removed."
 removedOtherLoginMessage: "<gray>You removed {0}'s login message."
 nameRequired: "<red>Policy requires that you must state your player name in your login message. You can either do this by inserting your name or %player%."
 rankRequired: "<red>Policy requires that you must state your rank in your login message. You can do this by using %rank% in your login message."
+# 0 - The material name
+# 1 - The players who have the material in their inventory
+playersWithMaterial: "<gray>Players with {0} in their inventory: {1}"
+nobodyHasThatMaterial: "<gray>No one online has that in their inventory."
+# 0 - The attempted material name
+materialNotFound: "<red>{0} is not a valid item/block name."