Implement tab completion for commands

src/dev/w1zzrd/invtweaks/listener/TabCompletionListener.java

@@ -0,0 +1,50 @@
+package dev.w1zzrd.invtweaks.listener;
+
+import org.bukkit.Material;
+import org.bukkit.NamespacedKey;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.server.TabCompleteEvent;
+
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * Listener for providing tab completions for all commands in this plugin
+ */
+public class TabCompletionListener implements Listener {
+
+    private static final List<NamespacedKey> materialTypes = Arrays.stream(Material.values())
+            .map(Material::getKey)
+            .sorted(Comparator.comparing(NamespacedKey::toString))
+            .collect(Collectors.toUnmodifiableList());
+
+    @EventHandler
+    public void onTabCompleteEvent(final TabCompleteEvent event) {
+        if (event.getSender() instanceof Player) {
+            final String buffer = event.getBuffer();
+            final List<String> completions = event.getCompletions();
+
+            if (buffer.startsWith("/search ")) {
+                final String[] split = buffer.split(" ");
+
+                if (split.length > 2) {
+                    completions.clear();
+                    event.setCancelled(true);
+                } else if (split.length == 2) {
+                    completions.addAll(materialTypes.stream().map(NamespacedKey::toString).filter(it -> it.contains(split[1])).collect(Collectors.toList()));
+                } else {
+                    completions.clear();
+                    completions.addAll(materialTypes.stream().map(NamespacedKey::toString).collect(Collectors.toList()));
+                }
+            } else if (buffer.startsWith("/magnet ")) {
+                completions.clear();
+            } else if (buffer.startsWith("/sort ")) {
+                completions.clear();
+            }
+        }
+    }
+}