import { Utils } from '../utils/utils';

interface MediatorFunction {
  (data?: any): any;
}


/**
 * @author Ahmed Ali Elfeky
 */
export class Mediator {

  private static listeners: Map<string, Map<string, MediatorFunction>> = new Map<string, Map<string, MediatorFunction>>();

  public static emit(channel: string, data?: any): void {
    let mediator: Map<string, MediatorFunction> = this.listeners.get(channel);
    if (!mediator) {
      mediator = new Map<string, MediatorFunction>();
      this.listeners.set(channel, mediator);
    }

    mediator.forEach((fun, channel, map) => {
      fun(data);
    });
  }

  public static subscribe(channel: string, fun: MediatorFunction): string {
    let mediator: Map<string, MediatorFunction> = this.listeners.get(channel);
    if (!mediator) {
      mediator = new Map<string, MediatorFunction>();
      this.listeners.set(channel, mediator);
    }

    let funId = Utils.generateUUID();
    mediator.set(funId, fun);
    return funId;
  }

  public static unsubscribe(channel: string, funId: string): void {
    let mediator: Map<string, MediatorFunction> = this.listeners.get(channel);
    if (mediator && mediator.has(funId)) {
      mediator.delete(funId);
    }
  }

}