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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function isPublic(ap) {
+ let mask = "_nomap";
+ let result = ap.ssid.indexOf(mask, ap.ssid.length - mask.length);
+ return result == -1;
+}
+
+function sort(a, b) {
+ return b.signal - a.signal;
+}
+
+function encode(ap) {
+ return { macAddress: ap.mac, signalStrength: ap.signal };
+}
+
+/**
+ * Shared utility functions for modules dealing with
+ * Location Services.
+ */
+
+export class LocationHelper {
+ static formatWifiAccessPoints(accessPoints) {
+ return accessPoints.filter(isPublic).sort(sort).map(encode);
+ }
+
+ /**
+ * Calculate the distance between 2 points using the Haversine formula.
+ * https://en.wikipedia.org/wiki/Haversine_formula
+ */
+ static distance(p1, p2) {
+ let rad = x => (x * Math.PI) / 180;
+ // Radius of the earth.
+ let R = 6371e3;
+ let lat = rad(p2.lat - p1.lat);
+ let lng = rad(p2.lng - p1.lng);
+
+ let a =
+ Math.sin(lat / 2) * Math.sin(lat / 2) +
+ Math.cos(rad(p1.lat)) *
+ Math.cos(rad(p2.lat)) *
+ Math.sin(lng / 2) *
+ Math.sin(lng / 2);
+
+ let c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
+
+ return R * c;
+ }
+}