import { AccessTokenCacheItem } from "./AccessTokenCacheItem";
import { Constants } from "./Constants";

/**
* @hidden
*/
export class Storage {// Singleton

  private static _instance: Storage;
  private _localStorageSupported: boolean;
  private _sessionStorageSupported: boolean;
  private _cacheLocation: string;

  constructor(cacheLocation: string) {
    if (Storage._instance) {
      return Storage._instance;
    }

    this._cacheLocation = cacheLocation;
    this._localStorageSupported = typeof window[this._cacheLocation] != "undefined" && window[this._cacheLocation] != null;
    this._sessionStorageSupported = typeof window[cacheLocation] != "undefined" && window[cacheLocation] != null;
    Storage._instance = this;
    if (!this._localStorageSupported && !this._sessionStorageSupported) {
      throw new Error("localStorage and sessionStorage not supported");
    }

    return Storage._instance;
  }

  // add value to storage
  setItem(key: string, value: string): void {
    if (window[this._cacheLocation]) {
      window[this._cacheLocation].setItem(key, value);
    } else {
      throw new Error("localStorage and sessionStorage are not supported");
    }
  }

  // get one item by key from storage
  getItem(key: string): string {
    if (window[this._cacheLocation]) {
      return window[this._cacheLocation].getItem(key);
    } else {
      throw new Error("localStorage and sessionStorage are not supported");
    }
  }

  // remove value from storage
  removeItem(key: string): void {
    if (window[this._cacheLocation]) {
      return window[this._cacheLocation].removeItem(key);
    } else {
      throw new Error("localStorage and sessionStorage are not supported");
    }
  }

  // clear storage (remove all items from it)
  clear(): void {
    if (window[this._cacheLocation]) {
      return window[this._cacheLocation].clear();
    } else {
      throw new Error("localStorage and sessionStorage are not supported");
    }
  }

  getAllAccessTokens(clientId: string, userIdentifier: string): Array<AccessTokenCacheItem> {
    const results: Array<AccessTokenCacheItem> = [];
    let accessTokenCacheItem: AccessTokenCacheItem;
    const storage = window[this._cacheLocation];
    if (storage) {
      let key: string;
      for (key in storage) {
        if (storage.hasOwnProperty(key)) {
          if (key.match(clientId) && key.match(userIdentifier)) {
            let value = this.getItem(key);
            if (value) {
              accessTokenCacheItem = new AccessTokenCacheItem(JSON.parse(key), JSON.parse(value));
              results.push(accessTokenCacheItem);
            }
          }
        }
      }
    } else {
      throw new Error("localStorage and sessionStorage are not supported");
    }

    return results;
  }

  removeAcquireTokenEntries(acquireTokenUser: string, acquireTokenStatus: string): void {
    const storage = window[this._cacheLocation];
    if (storage) {
      let key: string;
      for (key in storage) {
        if (storage.hasOwnProperty(key)) {
          if ((key.indexOf(acquireTokenUser) > -1) || (key.indexOf(acquireTokenStatus) > -1)) {
            this.removeItem(key);
          }
        }
      }
    } else {
      throw new Error("localStorage and sessionStorage are not supported");
    }
  }

  resetCacheItems(): void {
    const storage = window[this._cacheLocation];
    if (storage) {
      let key: string;
      for (key in storage) {
        if (storage.hasOwnProperty(key) && key.indexOf(Constants.msal) !== -1) {
          storage[key] = "";
        }
      }
    } else {
      throw new Error("localStorage and sessionStorage are not supported");
    }
  }
}