import { UUIDType, uuidTypes } from "./types";

export default class StorageHandler {
  static instance: StorageHandler;
  storage: Storage;

  constructor() {
    this.storage = sessionStorage;
  }


  /**
   * return sessionStorage instance
   *
   * @public
   * @return sessionStorage instance
   */
  static getInstance(): StorageHandler {
    if (!this.instance) {
      this.instance = new StorageHandler();
    }
    return this.instance;
  }


  /**
   * sessionStorage에 uuidType이 key인 uuidValue 저장
   *
   * @public
   */
  set(uuidType: UUIDType, uuidValue: string): void {
    this.storage.setItem(uuidType, uuidValue);
  }


  /**
   * uuidType이 key인 value return
   *
   * @public
   * @return uuidValue
   */
  get(uuidType: UUIDType): string {
    const uuidValue = this.storage.getItem(uuidType);
    if (null === uuidValue) {
      throw new Error("Session storage retrieval failed.");
    }
    return uuidValue;
  }

  /**
   * uuidType이 key인 value 삭제
   *
   * @public
   */
  delete(uuidType: UUIDType): void {
    this.storage.removeItem(uuidType);
  }

  /**
   * sessionStorage에 있는 값들 모두 삭제
   *
   * @public
   */
  clear() {
    uuidTypes.forEach((uuidType): void => {
      this.storage.removeItem(uuidType);
    });
  }
}