package speiger.src.coreengine.utils.eventbus;

import java.util.List;
import java.util.Set;
import java.util.function.Consumer;

import speiger.src.collections.objects.lists.ObjectArrayList;
import speiger.src.collections.objects.sets.ObjectLinkedOpenHashSet;

public class Listeners
{
	Set<Consumer<Event>>[] unsortedListeners = new Set[EventPriority.values().length];
	Consumer<Event>[] listeners = new Consumer[0];
	boolean rebuild = true;
	Listeners parent;
	List<Listeners> childs = null;
	
	public Listeners()
	{
		for(int i = 0;i<unsortedListeners.length;i++)
		{
			unsortedListeners[i] = new ObjectLinkedOpenHashSet<>();
		}
	}
	
	public Listeners(Listeners parent)
	{
		this();
		this.parent = parent;
		this.parent.addChild(this);
	}
	
	public void addChild(Listeners listener)
	{
		if(childs == null) childs = new ObjectArrayList<>();
		childs.add(listener);
	}
	
	public void addListener(EventPriority priority, Consumer<Event> listener)
	{
		if(unsortedListeners[priority.getPriority()].add(listener))
		{
			markDirty();
		}
	}
	
	public void removeListeners(Consumer<Event> listener)
	{
		for(int i = 0,m=unsortedListeners.length;i<m;i++)
		{
			if(unsortedListeners[i].remove(listener))
			{
				markDirty();
			}
		}
	}
	
	public void getListeners(EventPriority entry, List<Consumer<Event>> events)
	{
		events.addAll(unsortedListeners[entry.getPriority()]);
		if(parent != null)
		{
			parent.getListeners(entry, events);
		}
	}
	
	public Consumer<Event>[] getListeners()
	{
		if(rebuild) rebuildListeners();
		return listeners;
	}
	
	private void markDirty()
	{
		if(rebuild) return;
		rebuild = true;
		if(childs != null)
		{
			for(int i = 0,m=childs.size();i<m;i++)
			{
				childs.get(i).markDirty();
			}
		}
	}
	
	public void rebuildListeners()
	{
		rebuild = false;
		List<Consumer<Event>> result = new ObjectArrayList<>();
		for(EventPriority entry : EventPriority.getPriorities())
		{
			getListeners(entry, result);
		}
		listeners = result.toArray(new Consumer[result.size()]);
	}
}