package util;

using tink.CoreApi;

class EventBusListner {
	@:allow(util.EventBus)
	private final link:CallbackLink;

	@:allow(util.EventBus)
	private final eventName:String;

	@:allow(util.EventBus)
	private function new(link: CallbackLink,eventName: String) {
		this.link = link;
		this.eventName = eventName;
	}
}

/**
	Generic event handler.
**/
class EventBus<T>{
	private var listner: Map<String,SignalTrigger<T>> = new Map();

	public function new() {

	}
	
	public function on(eventName: String, callback: Callback<T>):EventBusListner{
		if (!listner.exists(eventName)){
			listner[eventName] = Signal.trigger();
		}

		var link = listner[eventName].asSignal().handle(callback);
		return new EventBusListner(link,eventName);
	}

	public function once(eventName: String,callback: Callback<T>):EventBusListner {
		if (!listner.exists(eventName)){
			listner[eventName] = Signal.trigger();
		}

		var link = listner[eventName].asSignal().handle(callback);
		return new EventBusListner(link,eventName);
	}

	public function emit(eventName: String, data: T) {
		if (listner.exists(eventName)){
			var trigger = listner[eventName];
			trigger.trigger(data);
		}
	}

	public function removeListner(id: EventBusListner) {
		if (!listner.exists(id.eventName)) {
			return;
		}
		id.link.cancel();
	}

}