// todo:@flow

import { AsyncStorage, Platform } from 'react-native';
import * as Debug from 'App/src/Debug';
import { toStringify } from 'App/src/utils/Utils';
import { addPrefix } from 'App/src/utils/AsyncStorage';

const location_key = addPrefix('location_enabled')

export const ENABLE_LOCATION = true;
export const DISABLE_LOCATION = false;
let enableLocation:boolean = DISABLE_LOCATION;
let position:any = {};
let watchInterval: any;

export const getEnableLocation = () => {
  return enableLocation;
};

const locationOptions = {
  enableHighAccuracy: true,
  timeout: 5000,  // 5 sec
  maximumAge: 30*60*1000,  // Upto 30 minutes
  distanceFilter: 100, // meters
};

export async function init() {
  Debug.logFn(() => `Location.init()...`);
  try {
    const enabled = await AsyncStorage.getItem(location_key);
    if (enabled === 'true') {
      enableLocation = ENABLE_LOCATION
      startLocationUpdates()
    }
  }
  catch (err) {
    Debug.logError(`Location.init(): error ${toStringify(err)}`);
  }
  Debug.logFn(() => `Location.init(): ...enableLocation ${enableLocation.toString()}`);
}

const startLocationUpdates = () => {
  if (Platform.OS === 'ios') {
    navigator.geolocation.requestAuthorization();
  }
  watchInterval = () => {
    navigator.geolocation.getCurrentPosition(onLocationSuccess, onLocationError, locationOptions);
    setInterval(watchInterval, 1800 * 1000)
  }
  watchInterval()
  Debug.logFn(() => `Watching position`);
}

export const setEnableLocation = (locOnOff:boolean) => {
  Debug.logFn(() => `setEnableLocation(): ${locOnOff.toString()}`);
  if (locOnOff && !enableLocation) {
    startLocationUpdates()
  }
  if (!locOnOff && enableLocation) {
    Debug.logFn(() => `Clearing location watch`);
    clearInterval(watchInterval);
  }
  enableLocation = locOnOff;
  AsyncStorage.setItem(location_key, locOnOff.toString())
};

export const getLastLocation = () => {
  return position;
};

export const getLocationData = () => {
  let data;
  if (getEnableLocation()) {
    const pos:any = getLastLocation();
    if (pos && pos.coords) {
      data = {
        last_known_location: {
          lat: pos.coords.latitude,
          lon: pos.coords.longitude,
          accuracy_meters: pos.coords.accuracy,
          timestamp_seconds: pos.timestamp/1000.0,
        }
      };
    }
  }
  return data;
};

const onLocationSuccess = (pos:any) => {
  Debug.logFn(() => `Got location update: ${JSON.stringify(pos)}`);
  position = pos;
};

const onLocationError = (err:any) => {
  Debug.logFn(() => `onLocationError: ${JSON.stringify(err)}`);
  if (enableLocation && err.PERMISSION_DENIED === 1) {
    startLocationUpdates()
  }
  Debug.logError(`Location request failed`, err);
};