(function(back) {
  const SETTINGS_FILE = "mylocation.json";

  // initialize with default settings...
  let s = {
    'lat': 51.5072,
    'lon': 0.1276,
    'location': "London"
  }

  // ...and overwrite them with any saved values
  // This way saved values are preserved if a new version adds more settings
  const storage = require('Storage')
  let settings = storage.readJSON(SETTINGS_FILE, 1) || {}
  const saved = settings || {}
  for (const key in saved) {
    s[key] = saved[key]
  }

  function save() {
    settings = s
    storage.write(SETTINGS_FILE, settings)
  }

  const locations = ["London", "Newcastle", "Edinburgh", "Paris", "New York", "Tokyo","???"];
  const lats = [51.5072 ,54.9783 ,55.9533 ,48.8566 ,40.7128 ,35.6762, 0.0];
  const lons = [-0.1276  ,-1.6178  ,-3.1883  ,2.3522  , -74.0060 ,139.6503, 0.0];

  E.showMenu({
    '': { 'title': 'My Location' },
    '< Back': back,
    'City': {
      value: 0 | locations.indexOf(s.location),
      min: 0, max: 6,
      format: v => locations[v],
      onchange: v => {
        if (v != 6) {
          s.location = locations[v];
          s.lat = lats[v];
          s.lon = lons[v];
          save();
        }
      },
    },
    'Set From GPS': ()=>setFromGPS()
  })

  function setFromGPS() {
    console.log("set from GPS");
    Bangle.setGPSPower(1);
    E.showMessage("Waiting for GPS fix. Place watch in the open. Could take 10 minutes. Long press to abort", "GPS Running");
    Bangle.setUI("updown", undefined);
  }

  Bangle.on('GPS', (gps) => {
    //console.log(".");
    if (gps.fix === 0) return;
    //console.log("fix from GPS");
    s = {'lat': gps.lat, 'lon': gps.lon, 'location': '???' }
    Bangle.buzz(1500); // buzz on first position
    Bangle.setGPSPower(0);
    save();

    Bangle.setUI("updown", ()=>{ load() });
    E.showPrompt("Location has been saved from the GPS fix",{
      title:"Location Saved",
      buttons : {"OK":1}
    }).then(function(v) {
      load(); // load default clock
    });
  });
  
})