function.php

<?php

require_once "db.class.php";
require_once "pointLocation.class.php";

const hood_mysql_fields = '
	ID as id,
	name,
	ESSID_AP as essid,
	BSSID_MESH as mesh_bssid,
	ESSID_MESH as mesh_essid,
	ESSID_MESH as mesh_id,
	protocol,
	channel2,
	mode2,
	mesh_type2,
	channel5,
	mode5,
	mesh_type5,
	upgrade_path,
	ntp_ip,
	UNIX_TIMESTAMP(changedOn) as timestamp,
	prefix, lat, lon
';

function debug($msg)
{
	if (DEBUG) {
		print_r($msg);
		echo "\n";
	}
}

/**
 * returns details error msg (as json)
 *
 * @param integer $code HTTP error 400, 500 or 503
 * @param string $msg Error message text
 */
function showError($code, $msg)
{
	http_response_code($code);

	header('Content-Type: application/json');

	$errorObject = array('error' => array('msg' => $msg, 'url' => 'http://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI']));
	print_r(json_encode($errorObject));
}

function sin_d($value)
{
	return sin(deg2rad($value));
}

function cos_d($value)
{
	return cos(deg2rad($value));
}

const EARTH_RADIUS = 6371;
/**
 * Haversine distance function in km
 * https://en.wikipedia.org/wiki/Haversine_formula
 *
 * @param double $lat1 latitude point 1
 * @param double $lon1 longitude point 1
 * @param double $lat2 latitude point 2
 * @param double $lon2 longitude point 2
 * @return integer distance between the points in km
 */
function distance_haversine($lat1, $lon1, $lat2, $lon2)
{
	$alpha = ($lat1 - $lat2) * 0.5;
	$beta = ($lon1 - $lon2) * 0.5;
	$sin_alpha = sin_d($alpha);
	$sin_beta = sin_d($beta);

	$a = $sin_alpha * $sin_alpha + cos_d($lat1) * cos_d($lat2) * $sin_beta * $sin_beta;
	$c = asin(min(1, sqrt($a)));
	$distance = 2 * EARTH_RADIUS * $c;

	return round($distance, 3);
}

/**
 * Check if the given geo coordinates are within one of the hoods.
 *
 * @param double $lat latitude point 1
 * @param double $lon longitude point 1
 * @return array hood data
 */
function getHoodByGeo($lat, $lon)
{
	$current_hood_dist = 99999999;
	$best_result = array();

	// load hoods from DB
	try {
		$q = 'SELECT '.hood_mysql_fields.' FROM hoods WHERE lat IS NOT NULL AND lon IS NOT NULL AND active=1;';
		$rs = db::getInstance()->prepare($q);
		$rs->execute();
	} catch (PDOException $e) {
		exit(showError(500, $e));
	}

	// check for every hood if it's nearer than the hood before
	while ($result = $rs->fetch(PDO::FETCH_ASSOC)) {
		debug("\n\nhood: " . $result['name'] . ', CenterLat: ' . $result['lat'] . ', hoodCenterLon: ' . $result['lon'] . ', hoodID: ' . $result['id']);

		$distance = distance_haversine($result['lat'], $result['lon'], $lat, $lon);
		debug('distance: $distance');

		if ($distance <= $current_hood_dist) {
			debug('Shorter distance found for hood ' . $result['id'] . '(' . $result['name'] . ')');
			$current_hood_dist = $distance;
			$best_result = $result;
		}
	}

	return $best_result;
}

/**
 * Get hood data based on KeyXchange ID.
 *
 * @param string $hoodid hood ID
 * @return array hood data
 */
function getHoodById($hoodid)
{
	// load hood from DB
	try {
		$q = 'SELECT '.hood_mysql_fields.' FROM hoods WHERE ID = :hoodid;';
		$rs = db::getInstance()->prepare($q);
		$rs->bindParam(':hoodid', $hoodid, PDO::PARAM_INT);
		$rs->execute();
	} catch (PDOException $e) {
		exit(showError(500, $e));
	}
	return $rs->fetch(PDO::FETCH_ASSOC);
}

function getTrainstation()
{
	return getHoodById(0);
}

function getAllVPNs($hoodId)
{
	$ret = array();

	// return all gateways in the hood
	try {
		$sql = "SELECT g.name, 'fastd' AS protocol, g.ip AS address, g.port, g.publickey AS 'key', g.contact
			FROM gateways AS g WHERE hood_ID=:hood AND active=1;";
		$rs = db::getInstance()->prepare($sql);
		$rs->bindParam(':hood', $hoodId);
		$rs->execute();
	} catch (PDOException $e) {
		exit(showError(500, $e));
	}
	while ($result = $rs->fetch(PDO::FETCH_ASSOC)) {
		array_push($ret, $result);
	}
	return $ret;
}

function getPolyhoodsByHood()
{
	try {
		$rs = db::getInstance()->query("
			SELECT polyhoods.polyid, lat, lon, hoodid
			FROM polyhoods INNER JOIN polygons ON polyhoods.polyid = polygons.polyid
			WHERE polyhoods.active=1
			ORDER BY hoodid ASC, polyid ASC, ID ASC;
		");
		$rs->execute();
	} catch (PDOException $e) {
		exit(showError(500, $e));
	}
	$result = $rs->fetchall(PDO::FETCH_ASSOC);
	$return = array();
	foreach($result as $row) {
		// one array of polygons per hood
		if(!isset($return[$row['hoodid']])) {
			$return[$row['hoodid']] = array();
		}
		// one array of vertices per polygon
		if(!isset($return[$row['hoodid']][$row['polyid']])) {
			$return[$row['hoodid']][$row['polyid']] = array();
		}
		$return[$row['hoodid']][$row['polyid']][] = array('lat' => floatval($row['lat']), 'lon' => floatval($row['lon']));
	}
	return $return;
}

function processPoly($point) {
	$hood = array();
	$pointLocation = new pointLocation();

	// First only retrieve list of polyids
	try {
		$rc = db::getInstance()->prepare("
			SELECT polyhoods.polyid, hoodid, MIN(polygons.lat) AS minlat, MIN(polygons.lon) AS minlon, MAX(polygons.lat) AS maxlat, MAX(polygons.lon) AS maxlon
			FROM polyhoods INNER JOIN polygons ON polyhoods.polyid = polygons.polyid
			INNER JOIN hoods ON hoods.ID = polyhoods.hoodid
			WHERE hoods.active=1 AND polyhoods.active=1
			GROUP BY polyid, hoodid
		"); // This query will automatically exclude polyhoods being present in polyhoods table, but without vertices in polygons table
		$rc->execute();
	} catch (PDOException $e) {
		exit(showError(500, $e));
	}

	// Set up all polygons, but do it without vertex coordinates
	$polystore = array();
	while($row = $rc->fetch(PDO::FETCH_ASSOC)) {
		$polystore[$row['polyid']] = $row;
		$polystore[$row['polyid']]['data'] = array(); // prepare array for vertex coordinates
	}

	// Now query the coordinates, all in one query
	try {
		$rc = db::getInstance()->prepare("SELECT polyid, lat, lon FROM polygons ORDER BY ID ASC");
		$rc->execute();
	} catch (PDOException $e) {
		exit(showError(500, $e));
	}

	// Write polygon coordinates into array
	while($row = $rc->fetch(PDO::FETCH_ASSOC)) {
		if(!isset($polystore[$row['polyid']])) {
			debug('Database inconsistent: No polyhood defined for ID '.$row['polyid']);
			continue; // Skip those orphaned vertex entries
		}
		$polystore[$row['polyid']]['data'][] = array(floatval($row["lon"]),floatval($row["lat"]));
		debug('lon: '.$row["lon"].' lat: '.$row["lat"]);
	}

	// Interpret polygon data
	foreach($polystore as $polygon) {
		// First check whether point coordinates are outside the most extreme values for lat/lng
		$exclude = $pointLocation->excludePolygon($point, $polygon['minlon'], $polygon['maxlon'], $polygon['minlat'], $polygon['maxlat']);
		if ($exclude) {
			debug("polygon #" . $polygon['polyid'] . " excluded<br>");
			continue;
		}
		// Now really check whether point is inside polygon
		$polygon['data'][] = $polygon['data'][0]; // Add first point as last point (= close polygon)
		$inside = $pointLocation->pointInPolygon($point, $polygon['data']);
		debug("point in polygon #" . $polygon['polyid'] . ": " . $inside . "<br>");
		if ($inside) {
			debug("PolyHood gefunden...");
			$hood = getHoodById($polygon['hoodid']);
			break;
		}
	}

	return $hood;
}

?>