import { EventEmitter, EventSubscription } from 'fbemitter';
import warning from 'fbjs/lib/warning';
import invariant from 'invariant';
import { AsyncStorage, DeviceEventEmitter, NativeModules, Platform } from 'react-native';

const { ExponentNotifications } = NativeModules;

type Notification = {
  origin: 'selected' | 'received';
  data: any;
  remote: boolean;
  isMultiple: boolean;
};

type LocalNotification = {
  title: string;
  // How should we deal with body being required on iOS but not on Android?
  body?: string;
  data?: any;
  ios?: {
    sound?: boolean;
  };
  android?: {
    channelId?: string;
    icon?: string;
    color?: string;
    sticky?: boolean;
    link?: string;
    // DEPRECATED:
    sound?: boolean;
    vibrate?: boolean | number[];
    priority: string;
  };
};

type Channel = {
  name: string;
  description?: string;
  priority?: string;
  sound?: boolean;
  vibrate?: boolean | number[];
  badge?: boolean;
};

// Android assigns unique number to each notification natively.
// Since that's not supported on iOS, we generate an unique string.
type LocalNotificationId = string | number;

let _emitter;
let _initialNotification;

function _maybeInitEmitter() {
  if (!_emitter) {
    _emitter = new EventEmitter();
    DeviceEventEmitter.addListener('Exponent.notification', _emitNotification);
  }
}

function _emitNotification(notification) {
  if (typeof notification === 'string') {
    notification = JSON.parse(notification);
  }

  /* Don't mutate the original notification */
  notification = { ...notification };

  if (typeof notification.data === 'string') {
    try {
      notification.data = JSON.parse(notification.data);
    } catch (e) {
      // It's actually just a string, that's fine
    }
  }

  _emitter.emit('notification', notification);
}

function _processNotification(notification) {
  notification = Object.assign({}, notification);

  if (!notification.data) {
    notification.data = {};
  }

  if (notification.hasOwnProperty('count')) {
    delete notification.count;
  }

  // Delete any Android properties on iOS and merge the iOS properties on root notification object
  if (Platform.OS === 'ios') {
    if (notification.android) {
      delete notification.android;
    }

    if (notification.ios) {
      notification = Object.assign(notification, notification.ios);
      delete notification.ios;
    }
  }

  // Delete any iOS properties on Android and merge the Android properties on root notification
  // object
  if (Platform.OS === 'android') {
    if (notification.ios) {
      delete notification.ios;
    }

    if (notification.android) {
      notification = Object.assign(notification, notification.android);
      delete notification.android;
    }
  }

  return notification;
}

function _validateNotification(notification) {
  if (Platform.OS === 'ios') {
    invariant(
      !!notification.title && !!notification.body,
      'Local notifications on iOS require both a title and a body'
    );
  } else if (Platform.OS === 'android') {
    invariant(!!notification.title, 'Local notifications on Android require a title');
  }
}

let ASYNC_STORAGE_PREFIX = '__expo_internal_channel_';
// TODO: remove this before releasing
// this will always be `true` for SDK 28+
let IS_USING_NEW_BINARY = typeof ExponentNotifications.createChannel === 'function';

async function _legacyReadChannel(id: string): Promise<Channel | null> {
  try {
    let channelString = await AsyncStorage.getItem(`${ASYNC_STORAGE_PREFIX}${id}`);
    if (channelString) {
      return JSON.parse(channelString);
    }
  } catch (e) {}
  return null;
}

function _legacyDeleteChannel(id: string): Promise<void> {
  return AsyncStorage.removeItem(`${ASYNC_STORAGE_PREFIX}${id}`);
}

if (Platform.OS === 'android') {
  AsyncStorage.clear = async function(callback?: (error?: Error) => void): Promise<void> {
    try {
      let keys = await AsyncStorage.getAllKeys();
      let result = null;
      if (keys && keys.length) {
        let filteredKeys = keys.filter(key => !key.startsWith(ASYNC_STORAGE_PREFIX));
        await AsyncStorage.multiRemove(filteredKeys);
      }
      callback && callback();
    } catch (e) {
      callback && callback(e);
      throw e;
    }
  };
}

// This codepath will never be triggered in SDK 28 and above
// TODO: remove before releasing
function _legacySaveChannel(id: string, channel: Channel): Promise<void> {
  return AsyncStorage.setItem(`${ASYNC_STORAGE_PREFIX}${id}`, JSON.stringify(channel));
}

export default {
  /* Only used internally to initialize the notification from top level props */
  _setInitialNotification(notification: Notification) {
    _initialNotification = notification;
  },

  /* Re-export */
  getExpoPushTokenAsync(): Promise<string> {
    return ExponentNotifications.getExponentPushTokenAsync();
  },

  getDevicePushTokenAsync: (config: {
    gcmSenderId?: string;
  }): Promise<{ type: string; data: string }> =>
    ExponentNotifications.getDevicePushTokenAsync(config || {}),

  createChannelAndroidAsync(id: string, channel: Channel): Promise<void> {
    if (Platform.OS === 'ios') {
      console.warn('createChannelAndroidAsync(...) has no effect on iOS');
      return Promise.resolve();
    }
    // This codepath will never be triggered in SDK 28 and above
    // TODO: remove before releasing
    if (!IS_USING_NEW_BINARY) {
      return _legacySaveChannel(id, channel);
    }
    return ExponentNotifications.createChannel(id, channel);
  },

  deleteChannelAndroidAsync(id: string): Promise<void> {
    if (Platform.OS === 'ios') {
      console.warn('deleteChannelAndroidAsync(...) has no effect on iOS');
      return Promise.resolve();
    }
    // This codepath will never be triggered in SDK 28 and above
    // TODO: remove before releasing
    if (!IS_USING_NEW_BINARY) {
      return Promise.resolve();
    }
    return ExponentNotifications.deleteChannel(id);
  },

  /* Shows a notification instantly */
  async presentLocalNotificationAsync(
    notification: LocalNotification
  ): Promise<LocalNotificationId> {
    _validateNotification(notification);
    let nativeNotification = _processNotification(notification);

    if (Platform.OS === 'ios') {
      return ExponentNotifications.presentLocalNotification(nativeNotification);
    } else {
      let _channel;
      if (nativeNotification.channelId) {
        _channel = await _legacyReadChannel(nativeNotification.channelId);
      }

      if (IS_USING_NEW_BINARY) {
        // delete the legacy channel from AsyncStorage so this codepath isn't triggered anymore
        _legacyDeleteChannel(nativeNotification.channelId);
        return ExponentNotifications.presentLocalNotificationWithChannel(
          nativeNotification,
          _channel
        );
      } else {
        // TODO: remove this codepath before releasing, it will never be triggered on SDK 28+
        // channel does not actually exist, so add its settings to the individual notification
        if (_channel) {
          nativeNotification.sound = _channel.sound;
          nativeNotification.priority = _channel.priority;
          nativeNotification.vibrate = _channel.vibrate;
        }
        return ExponentNotifications.presentLocalNotification(nativeNotification);
      }
    }
  },

  /* Schedule a notification at a later date */
  async scheduleLocalNotificationAsync(
    notification: LocalNotification,
    options: {
      time?: Date | number;
      repeat?: 'minute' | 'hour' | 'day' | 'week' | 'month' | 'year';
      intervalMs?: number;
    } = {}
  ): Promise<LocalNotificationId> {
    // set now at the beginning of the method, to prevent potential weird warnings when we validate
    // options.time later on
    const now = Date.now();

    // Validate and process the notification data
    _validateNotification(notification);
    let nativeNotification = _processNotification(notification);

    // Validate `options.time`
    if (options.time) {
      let timeAsDateObj: Date | null = null;
      if (options.time && typeof options.time === 'number') {
        timeAsDateObj = new Date(options.time);
        if (timeAsDateObj.toString() === 'Invalid Date') {
          timeAsDateObj = null;
        }
      } else if (options.time && options.time instanceof Date) {
        timeAsDateObj = options.time;
      }

      // If we couldn't convert properly, throw an error
      if (!timeAsDateObj) {
        throw new Error(
          `Provided value for "time" is invalid. Please verify that it's either a number representing Unix Epoch time in milliseconds, or a valid date object.`
        );
      }

      // If someone passes in a value that is too small, say, by an order of 1000 (it's common to
      // accidently pass seconds instead of ms), display a warning.
      warning(
        timeAsDateObj.getTime() >= now,
        `Provided value for "time" is before the current date. Did you possibly pass number of seconds since Unix Epoch instead of number of milliseconds?`
      );

      // If iOS, pass time as milliseconds
      if (Platform.OS === 'ios') {
        options = {
          ...options,
          time: timeAsDateObj.getTime(),
        };
      } else {
        options = {
          ...options,
          time: timeAsDateObj,
        };
      }
    }

    if (options.intervalMs != null && options.repeat != null) {
      throw new Error(`Pass either the "repeat" option or "intervalMs" option, not both`);
    }

    // Validate options.repeat
    if (options.repeat != null) {
      const validOptions = new Set(['minute', 'hour', 'day', 'week', 'month', 'year']);
      if (!validOptions.has(options.repeat)) {
        throw new Error(
          `Pass one of ['minute', 'hour', 'day', 'week', 'month', 'year'] as the value for the "repeat" option`
        );
      }
    }

    if (options.intervalMs != null) {
      if (Platform.OS === 'ios') {
        throw new Error(`The "intervalMs" option is not supported on iOS`);
      }

      if (options.intervalMs <= 0 || !Number.isInteger(options.intervalMs)) {
        throw new Error(
          `Pass an integer greater than zero as the value for the "intervalMs" option`
        );
      }
    }

    if (Platform.OS === 'ios') {
      return ExponentNotifications.scheduleLocalNotification(nativeNotification, options);
    } else {
      let _channel;
      if (nativeNotification.channelId) {
        _channel = await _legacyReadChannel(nativeNotification.channelId);
      }

      if (IS_USING_NEW_BINARY) {
        // delete the legacy channel from AsyncStorage so this codepath isn't triggered anymore
        _legacyDeleteChannel(nativeNotification.channelId);
        return ExponentNotifications.scheduleLocalNotificationWithChannel(
          nativeNotification,
          options,
          _channel
        );
      } else {
        // TODO: remove this codepath before releasing, it will never be triggered on SDK 28+
        // channel does not actually exist, so add its settings to the individual notification
        if (_channel) {
          nativeNotification.sound = _channel.sound;
          nativeNotification.priority = _channel.priority;
          nativeNotification.vibrate = _channel.vibrate;
        }
        return ExponentNotifications.scheduleLocalNotification(nativeNotification, options);
      }
    }
  },

  /* Dismiss currently shown notification with ID (Android only) */
  async dismissNotificationAsync(notificationId: LocalNotificationId): Promise<void> {
    if (Platform.OS === 'android') {
      return ExponentNotifications.dismissNotification(notificationId);
    } else {
      throw new Error('Dismissing notifications is not supported on iOS');
    }
  },

  /* Dismiss all currently shown notifications (Android only) */
  async dismissAllNotificationsAsync(): Promise<void> {
    if (Platform.OS === 'android') {
      return ExponentNotifications.dismissAllNotifications();
    } else {
      throw new Error('Dismissing notifications is not supported on iOS');
    }
  },

  /* Cancel scheduled notification notification with ID */
  cancelScheduledNotificationAsync(notificationId: LocalNotificationId): Promise<void> {
    return ExponentNotifications.cancelScheduledNotification(notificationId);
  },

  /* Cancel all scheduled notifications */
  cancelAllScheduledNotificationsAsync(): Promise<void> {
    return ExponentNotifications.cancelAllScheduledNotifications();
  },

  /* Primary public api */
  addListener(listener: Function): EventSubscription {
    _maybeInitEmitter();

    if (_initialNotification) {
      const initialNotification = _initialNotification;
      _initialNotification = null;
      setTimeout(() => {
        _emitNotification(initialNotification);
      }, 0);
    }

    return _emitter.addListener('notification', listener);
  },

  async getBadgeNumberAsync(): Promise<number> {
    if (!ExponentNotifications.getBadgeNumberAsync) {
      return 0;
    }
    return ExponentNotifications.getBadgeNumberAsync();
  },

  async setBadgeNumberAsync(number: number): Promise<void> {
    if (!ExponentNotifications.setBadgeNumberAsync) {
      return;
    }
    return ExponentNotifications.setBadgeNumberAsync(number);
  },
};