refactor(command): add CommandRegisterer

lib/src/main/java/net/tomatentum/marinara/wrapper/CommandRegisterer.java

@@ -0,0 +1,45 @@
+package net.tomatentum.marinara.wrapper;
+
+import java.util.Arrays;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import net.tomatentum.marinara.interaction.commands.SlashCommandDefinition;
+import net.tomatentum.marinara.util.ObjectAggregator;
+
+public class CommandRegisterer<A extends Object> {
+
+    public static <A extends Object> CommandRegisterer<A> of(Strategy<A> strategy, CommandConverter<A, ?, ?> converter) {
+        return new CommandRegisterer<A>(strategy, converter);
+    }
+
+    private Strategy<A> strategy;
+    private CommandConverter<A, ?, ?> converter;
+
+    CommandRegisterer(Strategy<A> strategy, CommandConverter<A, ?, ?> converter) {
+        this.strategy = strategy;
+        this.converter = converter;
+    }
+
+    public void register(SlashCommandDefinition[] slashDefs) {
+        Set<ServerCommandList<A>> serverCommands = new ObjectAggregator<SlashCommandDefinition, Long, ServerCommandList<A>>(
+                def -> Arrays.stream(def.serverIds()).boxed().toList(),
+                (l, o) -> l.add(converter.convert(o)),
+                ServerCommandList::new)
+            .aggregate(Arrays.asList(slashDefs)).stream()
+            .collect(Collectors.toSet());
+
+        Set<A> globalCommands = Arrays.stream(slashDefs)
+            .filter(x -> x.serverIds().length <= 0)
+            .map(converter::convert)
+            .collect(Collectors.toSet());
+
+        serverCommands.forEach(strategy::registerServer);
+        strategy.registerGlobal(globalCommands);
+    }
+    
+    public interface Strategy<A extends Object> {
+        void registerServer(ServerCommandList<A> commands);
+        void registerGlobal(Set<A> defs);
+    }
+}