type Callback = (...args: any) => void;
type EventId = number | string;

interface EventManager {
  eventList: Map<EventId, Set<Callback>>;
  on: (event: EventId, callback: Callback) => () => boolean;
  emit: (event: EventId, ...args: any) => boolean;
}

const eventManager: EventManager = {
  eventList: new Map(),
  on(event, callback) {
    this.eventList.has(event) || this.eventList.set(event, new Set());
    this.eventList.get(event)!.add(callback);

    return () => this.eventList.get(event)!.delete(callback);
  },
  emit(event, ...args) {
    if (!this.eventList.has(event)) {
      console.warn(
        `<${event}> Event is not registered. Did you forgot to bind the event ?`
      );
      return false;
    }
    this.eventList.get(event)!.forEach(cb => cb.call(this, ...args));

    return true;
  }
};

export { eventManager };