import { PhyHubClient } from '.';
import { PeripheralTwinInstance } from './peripheral-twin';
import { PeripheralInstance } from './types/twin.types';
import { DescriptorValidator } from './advisory-validation';

/**
 * registry to create, store and retrieve instances of different types of twins e.g. Device, Screen, Peripheral
 */

export class TwinRegistry {
  private peripheralInstances: Map<string, PeripheralTwinInstance> = new Map();

  constructor(private phyHubClient: PhyHubClient) {}

  // create an instance of PeripheralTwinInstance class.
  // `advisoryValidator` is optional opt-in advisory descriptor validation; when
  // supplied it is applied to the instance (also to an already-cached one, so the
  // opt-in is honored regardless of call order). Omit it for unchanged behavior.
  async getPeripheralInstance(
    twinId: string,
    advisoryValidator?: DescriptorValidator,
  ): Promise<PeripheralInstance | null> {
    try {
      // check whether we've already created instance for this twinId
      if (this.peripheralInstances.has(twinId)) {
        const cached = this.peripheralInstances.get(twinId)!;
        if (advisoryValidator) {
          cached.enableAdvisoryValidation(advisoryValidator);
        }
        return cached;
      }

      // create an object of PeripheralTwinInstance class
      const peripheralTwinInstance = new PeripheralTwinInstance(this.phyHubClient, twinId);

      // class object is created, but perform sanity checks such as whether PhyHubClient is valid, twinId is valid etc.
      // to make sure we are able to correct and return a valid instance
      await peripheralTwinInstance.initialize();

      if (advisoryValidator) {
        peripheralTwinInstance.enableAdvisoryValidation(advisoryValidator);
      }

      // set the newly created instance in the map for future use
      this.peripheralInstances.set(twinId, peripheralTwinInstance);

      return peripheralTwinInstance;
    } catch (error) {
      throw error;
    }
  }

  /**
   * Pool lookup WITHOUT creation (TECH-1394) — the client's ownership-loss
   * detection must only act on twins this app actually acquired; building an
   * instance for a foreign twinUpdated would be wrong (and would subscribe).
   */
  getCachedPeripheralInstance(twinId: string): PeripheralTwinInstance | undefined {
    return this.peripheralInstances.get(twinId);
  }

  /**
   * Drop a revoked instance from the pool (TECH-1394) so a later
   * getPeripheralInstance — e.g. after this app re-registers and takes the
   * twin back — builds a FRESH, non-revoked instance instead of returning
   * the poisoned cached one.
   */
  removePeripheralInstance(twinId: string): void {
    this.peripheralInstances.delete(twinId);
  }
}