import { TRPCError } from '@trpc/server';

type ClassName = any;

export class InstanceManager {
  private instanceMap: Map<number, Map<string, ClassName>>;

  constructor() {
    this.instanceMap = new Map();
  }
  /**
   * Clear instances by socket id.
   * @param socketId The socket id of each connection.
   */
  clearAllInstances(socketId: number) {
    this.instanceMap.get(socketId)?.clear();
    this.instanceMap.delete(socketId);
  }
  /**
   * Clear instance by socket id and instanceId.
   * @param socketId The socket id of each connection.
   * @param instanceId The instance id to be cleared.
   */
  clearInstance(socketId: number, instanceId: string) {
    this.instanceMap.get(socketId)?.delete(instanceId);
  }
  /**
   * Set instance by socket id and instance id.
   * @param socketId The socket id of each connection.
   * @param instanceId The id of instance.
   * @param intance Instance.
   */
  setInstance(socketId: number, instanceId: string, intance: ClassName) {
    if (!this.instanceMap.has(socketId)) {
      this.instanceMap.set(socketId, new Map());
    }
    this.instanceMap.get(socketId)!.set(instanceId, intance);
  }
  /**
   * Get instance by socket id and instance id.
   * @param socketId The socket id of each connection.
   * @param instanceId The id of instance.
   * @returns Instance.
   */
  getInstance(socketId: number, instanceId: string): ClassName {
    const map = this.instanceMap.get(socketId);
    if (map && map.get(instanceId)) {
      return map.get(instanceId)!;
    } else {
      throw new TRPCError({
        code: 'BAD_REQUEST',
        message: `The instance of instanceId(${instanceId}) of socketId(${socketId}) does not exist, please call 'createInstance' first.`
      });
    }
  }
}