WLBus is a pebble app to check the bus arrival time of CityBus in Lafayette and West Lafayette, IN.

app.js

/**
 * WLBus is a pebble app to check the bus arrival time of 
 * CityBus in Lafayette and West Lafayette, IN.
 * The data is downloaded from the website 
 * http://citybus.doublemap.com/map/
 *
 * NOTES
 *  - this software is a BETA version, I developed it in few days. 
 *    You can use it at your own risk.
 *  - the "home" and "work" stops are hardcoded here inside, search 
 *    for TODO comments to see where to change them.
 *  - I do not live in Lafayette anymore. If you are in need I may
 *    help you understanding and patching the code, but I do not 
 *    actively maintain it anymore.
 *
 * INSTALL
 * Go to cloud pebble https://cloudpebble.net, create a new 
 * pebble.js project and copy and paste this code in app.js file.
 * Check cloudpebble documentation for details about how to set up
 * the project and enable the developer mode in your pebble app.
 *
 * LICENSE
 *
 * The function distance is released under LGPLv3
 * See https://www.geodatasource.com/developers/javascript for details.
 * 
 * The rest of the code is released under GPLv3 or later.
 *
 * Copyright (c) 2016 Lorenzo Bossi
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * 
 */

var UI = require('ui');
var ajax = require('ajax');
var Wakeup = require('wakeup');
var Vibe = require('ui/vibe');

var checkAll;

var alarmCard = new UI.Card({
  title: 'WLBus',
  subtitle: 'Alarm',
  icon: 'images/wlbus',
  scrollable: false
});

var alarm = new UI.Menu({
  sections: [{
    title: 'Set alarm',
    items: [],
  }]
});

var main = new UI.Menu({
  sections: [{
    title: 'WLBus',
    items: [],
    onClick: function(e) {
      var min = e.item.wait[0];
      if (min < 5 && e.item.wait.length > 1) {
        min = e.item.wait[1];
      }
      var wait = [];
      if (min >= 2) {
        wait.push({title: '2 minute', minutes: 2});
      }
      for (var i = 5 ; i<min ; i+=5) {
        wait.push({title: i + ' minute', minutes: i});
      }
      alarm.items(0, wait);
      alarm.show();
    },
  }, {
    title: 'Settings',
    items: [{title: 'Refresh'}],
    onClick: function(e) {
      checkAll();
    },
  }]
});

var waitMsg = function(){
  var refresh = main.items(1)[0];
  refresh.subtitle = 'please wait...';
  main.item(1,0, refresh);
};
var waitMsgDone = function(){
  var refresh = main.items(1)[0];
  refresh.subtitle = '';
  main.item(1,0, refresh);  
};

main.on('select', function(e){
  e.section.onClick(e);
});


Wakeup.on('wakeup', function(e) {
  console.log('Wakeup event! ' + JSON.stringify(e));
  alarmCard.body('Time to take the bus!');
  alarmCard.show();
  Vibe.vibrate('long');
});

alarm.on('select', function(menu){
  var minutes = menu.item.minutes;
  Wakeup.cancel('all');
  Wakeup.schedule({
      time: Date.now() / 1000 + 60 * minutes,
      data: menu.item.title
    },
    function(alarmEvent) {
      if (alarmEvent.failed) {
        alarmCard.body('Fail to set the alarm ' + alarmEvent.error);
        Vibe.vibrate('short');
      } else {
        alarmCard.body('Alarm set ' + minutes + ' minutes from now');
      }
      alarmCard.show();
    }
  );
});

main.bus = []; // {title: text, subtitle: 'eta'}
main.update = function(){
  main.items(0, main.bus);
  main.selection(0, 0);
};

var checkEta = function(stop, callback) {
  var url = 'http://citybus.doublemap.com/map/v2/eta?stop=' + stop;
  console.log('Check eta ' + url );
  ajax({ url: url, type: 'json' },
    function(data) {
      try {
        var etas = data.etas[stop].etas;
        var wait = etas;
        wait.sort(function(a, b) {return a.avg - b.avg;});
        callback(true, wait);
      } catch (ex) {
        console.log('error ', url, ex.message);
        callback(false, ex.message);
      }
    },
    function() { 
      callback(false, 'connection'); 
    }
  );
};

var checkBus = function(text, stop, route) {
  console.log('Check bus ' + text + ' stop: ' + stop + ' route: ' + route);
  var bus = {title: text, subtitle: '?', wait: []};
  main.bus.push(bus);
  checkEta(stop, function(ok, wait) {
    if (ok) {
      wait = wait.filter(function(r){return r.route == route;}).map(function(r){return r.avg;});
      if ( wait.length > 0 ) {
        bus.subtitle = wait.slice(0, 2).join(', ');
      } else {
        bus.subtitle = 'no ETAs available';
      }
      bus.wait = wait;
    } else {
      bus.subtitle = 'ERR ' + wait;
    }
    main.update();
  });
};
var checkBuses = function(text, stop, routeNames) {
  console.log('checking buses on stop ' + stop);
  checkEta(stop, function(ok, wait) {
    console.log('next buses ' + ok + ' ' + JSON.stringify(wait));
    if (ok) {
      wait = wait.filter(function(r){
        return r.route in routeNames;
      }).map(function(r){
        return {bus: routeNames[r.route], avg: r.avg};
      });
      var buses = {};
      var anyBus = false;
      wait.forEach(function(next) {
        var bus;
        if ( buses[next.bus] ) {
          bus = buses[next.bus];
          anyBus = true;
        } else {
          var title = text + ' - ' + next.bus.short_name;
          bus = {title: title, subtitle: '?', wait: []};
          buses[next.bus] = bus;
          main.bus.push(bus);
        }
        if (bus.wait.length <= 2) {
          bus.wait.push(next.avg);
          bus.subtitle = bus.wait.join(', ');
        }
      });
      if ( !anyBus ) {
        main.bus.push({title: text, subtitle: 'no ETAs avaliable', wait: []});
      }
      console.log('nex buses processed ' + JSON.stringify(buses) + buses.length);
    } else {
      main.bus.push({title: text, subtitle: 'ERR ' + wait, wait: []});
      console.log('error ' + wait + ' checking stop ' + text);
    }
    main.update();
  });
};

var ajaxJson = function(url, fn) {
  ajax({ url: url, type: 'json' },
    fn,
    function() { 
      fn('error');
    }
  );
};

var Barrier = function(fn) {
  this._counter = 0;
  this._enabled = false;
  this._callback = fn;
};
Barrier.prototype._tryExec = function() {
  if (this._enabled === true && this._counter === 0) {
    console.log('barrier, executing callback');
    this._callback.call(null);
  } else {
    console.log('barrier, NOT executing callback, waiting ' + this._counter);
  }
};
Barrier.prototype.enable = function(){
  if (this._enabled === true) {
    throw 'The barrier has been already enabled.';
  }
  this._enabled = true;
  this._tryExec();
};
Barrier.prototype.add = function(fn){
  if (this._enabled === true) {
    throw 'The barrier has been already enabled.';
  }
  this._counter ++;
  var This = this;
  return function() {
    This._counter --;
    try {
      fn.apply(null, arguments);
    } catch (ex) {
      console.log('error in barrier callback', ex.message);
    }
    This._tryExec();
  };
};

// https://www.geodatasource.com/developers/javascript
// LGPLv3
var distance = function(lat1, lon1, lat2, lon2, unit) {
	var radlat1 = Math.PI * lat1/180;
	var radlat2 = Math.PI * lat2/180;
	var theta = lon1-lon2;
	var radtheta = Math.PI * theta/180;
	var dist = Math.sin(radlat1) * Math.sin(radlat2) + Math.cos(radlat1) * Math.cos(radlat2) * Math.cos(radtheta);
	dist = Math.acos(dist);
	dist = dist * 180/Math.PI;
	dist = dist * 60 * 1.1515;
	if (unit=="K") { dist = dist * 1.609344; }
	if (unit=="N") { dist = dist * 0.8684; }
	return dist;
};

checkAll = function() {
  waitMsg();
  main.bus = [];
  var homeOfficeRoute = false;
  var stopOffice = false;
  var stopHome = false;
  var stops = false;
  var currentPos = false;
  var routeNames = [];
  
  var barrier = new Barrier(function() {
    console.log('Check bus route ' + homeOfficeRoute + ' stopOffice '+ stopOffice +' stopHome '+ stopHome);
    checkBus('time to home: ', stopOffice, homeOfficeRoute);
    checkBus('time to work: ', stopHome, homeOfficeRoute);
    
    for (var n = 0 ; n < stops.length ; n++) {
      var stop = stops[n];
      var idx = stop.name.lastIndexOf(' - ');
      if (idx >= 0) {
        stop.short_name = stop.name.substr(idx + 3);
      } else {
        stop.short_name = stop.name;  
      }
      stop.distance = distance(currentPos.latitude, currentPos.longitude, stop.lat, stop.lon);
    }
    stops.sort(function(a, b) {return a.distance - b.distance;});
    console.log('by distance: ' + JSON.stringify(stops));
    checkBuses(stops[0].short_name, stops[0].id, routeNames);
    checkBuses(stops[1].short_name, stops[1].id, routeNames);
    
    waitMsgDone();
  });
  
  navigator.geolocation.getCurrentPosition( barrier.add(function(pos){
    console.log('gps', JSON.stringify(pos), pos.coords.latitude, pos.coords.longitude );
    currentPos = pos.coords;
  }), function() {console.log('GPS error');}, {enableHighAccuracy: true, maximumAge: 1000*60*5});
  
  ajaxJson('http://citybus.doublemap.com/map/v2/routes', barrier.add(function(routes){
    console.log('Routes downloaded: ' + JSON.stringify(routes));
    for (var n = 0 ; n < routes.length ; n++) {
      var route = routes[n];
      if (route.short_name == '5B'){ //TODO this is the line "office" <--> "home"
        console.log('route id found ' + route.id);
        homeOfficeRoute = route.id;
      }
      routeNames[route.id] = route;
    }
  }));
  ajaxJson('http://citybus.doublemap.com/map/v2/stops', barrier.add(function(data){
    console.log('Stops downloaded: ' + JSON.stringify(data));
    stops = data;
    for (var n = 0 ; n < stops.length ; n++) {
      var stop = stops[n];
      if (stop.name == 'Beering Hall on University St (@Shelter) - BUS389'){  //TODO this is the stop "office"
        console.log('stopOffice id found ' + stop.id);
        stopOffice = stop.id;
      }
      if (stop.name == 'Carlisle Rd & Windsor Dr (NW Corner) - BUS623NW'){ //TODO this is the stop "home"
        console.log('stopHome id found ' + stop.id);
        stopHome = stop.id;
      }
    }
  }));
  
  barrier.enable();  
};


checkAll();
main.show();