/**
 * @license
 * Copyright 2017 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 { FirebaseApp, _getProvider, getApp } from '@firebase/app-exp';
import {
  FirebaseMessaging,
  GetTokenOptions,
  MessagePayload
} from './interfaces/public-types';
import {
  NextFn,
  Observer,
  Unsubscribe,
  getModularInstance
} from '@firebase/util';

import { MessagingService } from './messaging-service';
import { deleteToken as _deleteToken } from './api/deleteToken';
import { getToken as _getToken } from './api/getToken';
import { onBackgroundMessage as _onBackgroundMessage } from './api/onBackgroundMessage';
import { onMessage as _onMessage } from './api/onMessage';

/**
 * Retrieves a Firebase Cloud Messaging instance.
 *
 * @returns The Firebase Cloud Messaging instance associated with the provided firebase app.
 *
 * @public
 */
export function getMessagingInWindow(
  app: FirebaseApp = getApp()
): FirebaseMessaging {
  return _getProvider(getModularInstance(app), 'messaging-exp').getImmediate();
}

/**
 * Retrieves a Firebase Cloud Messaging instance.
 *
 * @returns The Firebase Cloud Messaging instance associated with the provided firebase app.
 *
 * @public
 */
export function getMessagingInSw(
  app: FirebaseApp = getApp()
): FirebaseMessaging {
  return _getProvider(
    getModularInstance(app),
    'messaging-sw-exp'
  ).getImmediate();
}

/**
 * Subscribes the `FirebaseMessaging` instance to push notifications. Returns an Firebase Cloud
 * Messaging registration token that can be used to send push messages to that `FirebaseMessaging`
 * instance.
 *
 * If a notification permission isn't already granted, this method asks the user for permission. The
 * returned promise rejects if the user does not allow the app to show notifications.
 *
 * @param messaging - The `FirebaseMessaging` instance.
 * @param options - Provides an optional vapid key and an optinoal service worker registration
 *
 * @returns The promise resolves with an FCM registration token.
 *
 * @public
 */
export async function getToken(
  messaging: FirebaseMessaging,
  options?: GetTokenOptions
): Promise<string> {
  messaging = getModularInstance(messaging);
  return _getToken(messaging as MessagingService, options);
}

/**
 * Deletes the registration token associated with this `FirebaseMessaging` instance and unsubscribes
 * the `FirebaseMessaging` instance from the push subscription.
 *
 * @param messaging - The `FirebaseMessaging` instance.
 *
 * @returns The promise resolves when the token has been successfully deleted.
 *
 * @public
 */
export function deleteToken(messaging: FirebaseMessaging): Promise<boolean> {
  messaging = getModularInstance(messaging);
  return _deleteToken(messaging as MessagingService);
}

/**
 * When a push message is received and the user is currently on a page for your origin, the
 * message is passed to the page and an `onMessage()` event is dispatched with the payload of
 * the push message.
 *
 *
 * @param messaging - The `FirebaseMessaging` instance.
 * @param nextOrObserver - This function, or observer object with `next` defined,
 *     is called when a message is received and the user is currently viewing your page.
 * @returns To stop listening for messages execute this returned function.
 *
 * @public
 */
export function onMessage(
  messaging: FirebaseMessaging,
  nextOrObserver: NextFn<MessagePayload> | Observer<MessagePayload>
): Unsubscribe {
  messaging = getModularInstance(messaging);
  return _onMessage(messaging as MessagingService, nextOrObserver);
}

/**
 * Called when a message is received while the app is in the background. An app is considered to be
 * in the background if no active window is displayed.
 *
 * @param messaging - The `FirebaseMessaging` instance.
 * @param nextOrObserver - This function, or observer object with `next` defined, is called when a
 * message is received and the app is currently in the background.
 *
 * @returns To stop listening for messages execute this returned function
 *
 * @public
 */
export function onBackgroundMessage(
  messaging: FirebaseMessaging,
  nextOrObserver: NextFn<MessagePayload> | Observer<MessagePayload>
): Unsubscribe {
  messaging = getModularInstance(messaging);
  return _onBackgroundMessage(messaging as MessagingService, nextOrObserver);
}