Add support for themes (fixes #1925)

gui/default/syncthing/core/languageSelectDirective.js

@@ -0,0 +1,48 @@
+angular.module('syncthing.core')
+    .directive('languageSelect', function (LocaleService) {
+        'use strict';
+        return {
+            restrict: 'EA',
+            template:
+                    '<a ng-if="visible" href="#" class="dropdown-toggle" data-toggle="dropdown" aria-expanded="true"><span class="fa fa-globe"></span>&nbsp;{{localesNames[currentLocale] || "English"}} <span class="caret"></span></a>'+
+                    '<ul ng-if="visible" class="dropdown-menu">'+
+                        '<li ng-repeat="(i,name) in localesNames" ng-class="{active: i==currentLocale}">'+
+                            '<a href="#" data-ng-click="changeLanguage(i)">{{name}}</a>'+
+                        '</li>'+
+                    '</ul>',
+
+            link: function ($scope) {
+                var availableLocales = LocaleService.getAvailableLocales();
+                var localeNames = LocaleService.getLocalesDisplayNames();
+                var availableLocaleNames = {};
+
+                // get only locale names that present in available locales
+                for (var i = 0; i < availableLocales.length; i++) {
+                    var a = availableLocales[i];
+                    if (localeNames[a]) {
+                        availableLocaleNames[a] = localeNames[a];
+                    } else {
+                        // show code lang if it is not in the dict
+                        availableLocaleNames[a] = '[' + a + ']';
+                    }
+                }
+
+                $scope.localesNames = availableLocaleNames;
+                $scope.visible = $scope.localesNames && $scope.localesNames['en'];
+
+                // using $watch cause LocaleService.currentLocale will be change after receive async query accepted-languages
+                // in LocaleService.readBrowserLocales
+                var remove_watch = $scope.$watch(LocaleService.getCurrentLocale, function (newValue) {
+                    if (newValue) {
+                        $scope.currentLocale = newValue;
+                        remove_watch();
+                    }
+                });
+
+                $scope.changeLanguage = function (locale) {
+                    LocaleService.useLocale(locale, true);
+                    $scope.currentLocale = locale;
+                };
+            }
+        };
+    });