Implement multiverse generator plugin hook

platforms/bukkit/common/build.gradle.kts

@@ -1,12 +1,17 @@
 repositories {
-
+    maven {
+        name = "onarandombox"
+        url = uri("https://repo.onarandombox.com/multiverse-releases")
+    }
 }
 
 dependencies {
     shadedApi(project(":common:implementation:base"))
 
     compileOnly("io.papermc.paper", "paper-api", Versions.Bukkit.paper)
 
+    compileOnly("org.mvplugins.multiverse.core", "multiverse-core", "5.0.0")
+
     shadedApi("io.papermc", "paperlib", Versions.Bukkit.paperLib)
 
     shadedApi("com.google.guava", "guava", Versions.Libraries.Internal.guava)

platforms/bukkit/common/src/main/java/com/dfsek/terra/bukkit/TerraBukkitPlugin.java

@@ -87,7 +87,7 @@ public void onEnable() {
             return;
         }
 
-        Bukkit.getPluginManager().registerEvents(new CommonListener(), this); // Register master event listener
+        Bukkit.getPluginManager().registerEvents(new CommonListener(platform), this); // Register master event listener
         PaperUtil.checkPaper(this);
     }
 

platforms/bukkit/common/src/main/java/com/dfsek/terra/bukkit/hooks/MultiverseGeneratorPluginHook.java

@@ -0,0 +1,47 @@
+package com.dfsek.terra.bukkit.hooks;
+
+import com.dfsek.terra.api.Platform;
+import com.dfsek.terra.api.registry.key.Keyed;
+
+import org.mvplugins.multiverse.core.world.generators.GeneratorPlugin;
+import org.mvplugins.multiverse.external.jetbrains.annotations.NotNull;
+import org.mvplugins.multiverse.external.jetbrains.annotations.Nullable;
+
+import java.util.Collection;
+
+public final class MultiverseGeneratorPluginHook implements GeneratorPlugin {
+
+    private final Platform platform;
+
+    public MultiverseGeneratorPluginHook(Platform platform) {
+        this.platform = platform;
+    }
+
+    @Override
+    public @NotNull Collection<String> suggestIds(@Nullable String s) {
+        return platform.getConfigRegistry().entries().stream()
+            .map(Keyed::getID)
+            .toList();
+    }
+
+    @Override
+    public @Nullable Collection<String> getExampleUsages() {
+        return platform.getConfigRegistry()
+            .entries()
+            .stream()
+            .map(Keyed::getID)
+            .map("/mv create example_world NORMAL -g Terra:%s"::formatted)
+            .limit(5) // reasonable amount
+            .toList();
+    }
+
+    @Override
+    public @Nullable String getInfoLink() {
+        return "https://terra.polydev.org/";
+    }
+
+    @Override
+    public @NotNull String getPluginName() {
+        return "Terra";
+    }
+}

platforms/bukkit/common/src/main/java/com/dfsek/terra/bukkit/listeners/CommonListener.java

@@ -17,13 +17,40 @@
 
 package com.dfsek.terra.bukkit.listeners;
 
+import com.dfsek.terra.api.Platform;
+import com.dfsek.terra.bukkit.hooks.MultiverseGeneratorPluginHook;
+
+import org.bukkit.event.EventHandler;
 import org.bukkit.event.Listener;
+import org.bukkit.event.server.PluginEnableEvent;
+import org.mvplugins.multiverse.core.MultiverseCoreApi;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 
 /**
  * Listener for events on all implementations.
  */
 public class CommonListener implements Listener {
-    public CommonListener() {
+    private static final Logger logger = LoggerFactory.getLogger(CommonListener.class);
+    private final Platform platform;
+
+    public CommonListener(Platform platform) {
+        this.platform = platform;
+    }
+
+    @EventHandler
+    public void onPluginEnable(PluginEnableEvent event) {
+        if(event.getPlugin().getName().equals("Multiverse-Core")) {
+            try {
+                Class.forName("org.mvplugins.multiverse.core.MultiverseCoreApi");
+                MultiverseCoreApi.get().getGeneratorProvider()
+                    .registerGeneratorPlugin(new MultiverseGeneratorPluginHook(platform));
+            } catch(ClassNotFoundException e) {
+                logger.debug("Multiverse v5 is not installed.");
+            } catch(IllegalStateException e) {
+                logger.error("Failed to register Terra generator plugin to multiverse.", e);
+            }
+        }
     }
 }