import type { EventBusCallback } from './app-types';
import { Logger } from './logger';

export class EventBus {
  private static eventRegister: Map<string, Array<EventBusCallback>> = new Map<
    string,
    Array<EventBusCallback>
  >();

  static on(eventName: string, callback: EventBusCallback): void {
    Logger.logDbg(`Registering Listener for event: ${eventName}`);
    if (!this.eventRegister.has(eventName)) {
      this.eventRegister.set(eventName, [callback]);
    } else {
      this.eventRegister.get(eventName).push(callback);
    }
  }

  /**
   * Remove a specific callback for an event
   * @param eventName Event name to remove callback from
   * @param callback The callback function to remove
   */
  static off(eventName: string, callback: EventBusCallback): void {
    if (this.eventRegister.has(eventName)) {
      const callbacks = this.eventRegister.get(eventName);
      const index = callbacks.indexOf(callback);
      if (index > -1) {
        callbacks.splice(index, 1);
        Logger.logDbg(`Removed listener for event: ${eventName}`);
      }
      // Clean up empty arrays
      if (callbacks.length === 0) {
        this.eventRegister.delete(eventName);
      }
    }
  }

  /**
   * Remove all callbacks for a specific event
   * @param eventName Event name to clear all listeners for
   */
  static clearEvent(eventName: string): void {
    if (this.eventRegister.has(eventName)) {
      this.eventRegister.delete(eventName);
      Logger.logDbg(`Cleared all listeners for event: ${eventName}`);
    }
  }

  /**
   * Remove all event listeners (used during SDK shutdown)
   */
  static clearAll(): void {
    this.eventRegister.clear();
    Logger.logDbg('Cleared all event listeners');
  }

  static triggerEvent(eventName: string, payload: any): void {
    if (this.eventRegister.has(eventName)) {
      for (const cb of this.eventRegister.get(eventName)) {
        try {
          Logger.logDbg(
            `Sending event ${eventName} to all listeners. Count = ${
              this.eventRegister.get(eventName).length
            }`
          );
          cb(eventName, payload);
        } catch (err) {
          Logger.logError('Unable to process callback for event: ' + eventName);
        }
      }
    }
  }
}