<?php
/* phpTrackme
 *
 * Copyright(C) 2013 Bartek Fabiszewski (www.fabiszewski.net)
 * Copyright(C) 2014 Mark Campbell-Smith (campbellsmith.me)
 *
 * This is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Library General Public License as published by
 * the Free Software Foundation; either version 2 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 Library General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
require_once("auth.php");

$userid = ((isset($_REQUEST["userid"]) && is_numeric($_REQUEST["userid"])) ? $_REQUEST["userid"] : 0);
$trackid = ((isset($_REQUEST["trackid"]) && is_numeric($_REQUEST["trackid"])) ? $_REQUEST["trackid"] : 0);

function haversine_distance($lat1, $lon1, $lat2, $lon2) {
  $lat1 = deg2rad($lat1);
  $lon1 = deg2rad($lon1);
  $lat2 = deg2rad($lat2);
  $lon2 = deg2rad($lon2);
  $latD = $lat2 - $lat1;
  $lonD = $lon2 - $lon1;
  $angle = 2*asin(sqrt(pow(sin($latD/2),2)+cos($lat1)*cos($lat2)*pow(sin($lonD/2),2)));
  return $angle * 6371000;
}

if ($userid) {
  if ($trackid) {
    // get all track data
    $query = $mysqli->prepare("SELECT positions.ID,positions.Latitude,positions.Longitude,positions.Pace,positions.DateAdded,positions.TotalDistance,positions.TotalTime,positions.EventType,users.username,trips.Name,trips.ID FROM positions LEFT JOIN users ON (positions.FK_Users_ID=users.ID) LEFT JOIN trips ON (positions.FK_Trips_ID=trips.ID) WHERE positions.FK_Users_ID=? AND positions.FK_Trips_ID=? ORDER BY positions.DateAdded");
    $query->bind_param('ii', $userid, $trackid);
  }
  else {
    // get data only for latest point
    $query = $mysqli->prepare("SELECT positions.ID,positions.Latitude,positions.Longitude,positions.Pace,positions.DateAdded,positions.TotalDistance,positions.TotalTime,positions.EventType,users.username,trips.Name,trips.ID FROM positions LEFT JOIN users ON (positions.FK_Users_ID=users.ID) LEFT JOIN trips ON (positions.FK_Trips_ID=trips.ID) WHERE positions.FK_Users_ID=? ORDER BY positions.DateAdded DESC LIMIT 1");
    $query->bind_param('i', $userid);    
  }
  $query->execute();
  $query->bind_result($positionid,$latitude,$longitude,$pace,$dateadded,$totaldistance,$totaltime,$eventtype,$username,$trackname,$trackid);

  header("Content-type: text/xml");
  $xml = new XMLWriter();
  $xml->openURI("php://output");
  $xml->startDocument("1.0");
  $xml->setIndent(true);
  $xml->startElement('root');
  
  while ($query->fetch()) {
    $xml->startElement("position");
    $xml->writeAttribute("id", $positionid);
      $xml->writeElement("latitude", $latitude); 
      $xml->writeElement("longitude", $longitude); 
      $xml->writeElement("pace", $pace); 
      $xml->writeElement("dateadded", $dateadded);   
      $xml->writeElement("TotalDistance", $totaldistance); 
      $xml->writeElement("TotalTime", $totaltime); 
      $xml->writeElement("EventType", $eventtype); 
      
      $xml->writeElement("username", $username);   
      $xml->writeElement("trackid", $trackid); 
      $xml->writeElement("trackname", $trackname); 
      $distance = (isset($prev_latitude))?haversine_distance($prev_latitude,$prev_longitude,$latitude,$longitude):0;
      $prev_latitude = $latitude;
      $prev_longitude = $longitude;
      $xml->writeElement("distance", round($distance));   
      $seconds = (isset($prev_dateadded))?(strtotime($dateadded)-strtotime($prev_dateadded)):0;
      $prev_dateadded = $dateadded;
      $xml->writeElement("seconds", $seconds);   
    $xml->endElement();    
  }
  
  $xml->endElement();
  $xml->endDocument();  
  $xml->flush();

  $query->free_result();
}

$mysqli->close();
?>