import { Injectable } from '@angular/core';
import { AlternativeStorage } from './alternativestorage';

/*
 * Represents a localStorage store.
 */
@Injectable()
export class LocalStorage {
  private storage: Storage;

  constructor() {
    this.storage = this.getStorage();
  }

  /*
   * Safari, in Private Browsing Mode, looks like it supports localStorage but all calls to setItem
   * throw QuotaExceededError. We're going to detect this and just silently drop any calls to
   * setItem
   * to avoid the entire page breaking, without having to do a check at each usage of Storage.
   */
  private getStorage(): Storage {
    try {
      const storage = localStorage;
      storage.setItem('ng2IdleStorage', '');
      storage.removeItem('ng2IdleStorage');
      return storage;
    } catch (err) {
      return new AlternativeStorage();
    }
  }

  /*
   * Gets an item in the storage.
   *
   * @param value - The value to get.
   * @return The current value.
   */
  getItem(key: string): string | null {
    return this.storage.getItem('ng2Idle.' + key);
  }

  /*
   * Removes an item in the storage.
   *
   * @param value - The value to remove.
   */
  removeItem(key: string): void {
    this.storage.removeItem('ng2Idle.' + key);
  }

  /*
   * Sets an item in the storage.
   *
   * @param key - The key to set the value.
   * @param value - The value to set to the key.
   */
  setItem(key: string, data: string): void {
    this.storage.setItem('ng2Idle.' + key, data);
  }

  /*
   * Represents the storage, commonly use for testing purposes.
   *
   * @param key - The key to set the value.
   * @param value - The value to set to the key.
   */
  _wrapped(): Storage {
    return this.storage;
  }
}