/**
 * @license
 * Copyright 2019 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import { Persistence } from '../../model/public_types';

export const enum PersistenceType {
  SESSION = 'SESSION',
  LOCAL = 'LOCAL',
  NONE = 'NONE'
}

export type PersistedBlob = Record<string, unknown>;

export interface Instantiator<T> {
  (blob: PersistedBlob): T;
}

export type PersistenceValue = PersistedBlob | string;

export const STORAGE_AVAILABLE_KEY = '__sak';

export interface StorageEventListener {
  (value: PersistenceValue | null): void;
}

export interface PersistenceInternal extends Persistence {
  type: PersistenceType;
  _isAvailable(): Promise<boolean>;
  _set(key: string, value: PersistenceValue): Promise<void>;
  _get<T extends PersistenceValue>(key: string): Promise<T | null>;
  _remove(key: string): Promise<void>;
  _addListener(key: string, listener: StorageEventListener): void;
  _removeListener(key: string, listener: StorageEventListener): void;
}