import _ from "lodash";
import MetricService from "../services/metric.service";
import { DDBConnector } from "./connector/DDBConnector";

export abstract class AbstractModel<T> {
  idPrefix: string;
  connector: DDBConnector;
  metricService: MetricService;

  constructor(connector: DDBConnector) {
    this.idPrefix = "";
    this.connector = connector;
    this.metricService = MetricService.getInstance();
  }

  async findById(id: string | number, suffix: string | null = null): Promise<T | null> {
    const key = this.buildCbKey(id, suffix);
    return this.connector.get<T>(key);
  }

  async findByMultipleId(
    ids: (string | number)[],
    suffix: string | null = null
  ): Promise<Record<string, T | null>> {
    const keysToIds: Record<string, string | number> = {};
    const keys: string[] = [];

    for (const id of ids) {
      const key = this.buildCbKey(id, suffix);
      keysToIds[key] = id;
      keys.push(key);
    }

    const items = await this.connector.batchGet<T>(keys);
    return _.mapKeys(items, (_v, k) => keysToIds[k]);
  }

  save(id: string | number, data: any, options = { expiry: 86400 }) {
    const key = this.buildCbKey(id);
    return this.connector.save(key, data, options);
  }

  async counter(id: string | number, delta: number = 1) {
    const key = this.buildCbKey(id);
    return this.connector.counter(key, delta);
  }

  private buildCbKey(id: string | number, suffix: string | null = null): string {
    let key = id + "";

    if (key.substring(0, this.idPrefix.length) !== this.idPrefix) {
      key = this.idPrefix + key;
    }

    if (suffix !== null) {
      key += suffix;
    }

    return key;
  }
}