improved language picker (#6890)

* improved language picker

* fix import path

* update tests

lib/core/services/language.service.ts

@@ -0,0 +1,73 @@
+/*!
+ * @license
+ * Copyright 2019 Alfresco Software, Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { Injectable } from '@angular/core';
+import { Direction } from '@angular/cdk/bidi';
+import { BehaviorSubject } from 'rxjs';
+import { AppConfigService, AppConfigValues } from '../app-config/app-config.service';
+import { UserPreferencesService } from './user-preferences.service';
+
+export interface LanguageItem {
+    key: string;
+    label: string;
+    direction?: Direction;
+}
+
+@Injectable({providedIn: 'root'})
+export class LanguageService {
+
+    private languages = new BehaviorSubject<LanguageItem[]>([
+        {'key': 'de', 'label': 'Deutsch'},
+        {'key': 'en', 'label': 'English'},
+        {'key': 'es', 'label': 'Español'},
+        {'key': 'fr', 'label': 'Français'},
+        {'key': 'it', 'label': 'Italiano'},
+        {'key': 'ja', 'label': '日本語'},
+        {'key': 'nb', 'label': 'Bokmål'},
+        {'key': 'nl', 'label': 'Nederlands'},
+        {'key': 'pt-BR', 'label': 'Português (Brasil)'},
+        {'key': 'ru', 'label': 'Русский'},
+        {'key': 'zh-CN', 'label': '中文简体'},
+        {'key': 'cs', 'label': 'Čeština'},
+        {'key': 'da', 'label': 'Dansk'},
+        {'key': 'fi', 'label': 'Suomi'},
+        {'key': 'pl', 'label': 'Polski'},
+        {'key': 'sv', 'label': 'Svenska'},
+        {'key': 'ar', 'label': 'العربية', direction: 'rtl'}
+    ]);
+
+    languages$ = this.languages.asObservable();
+
+    constructor(
+        appConfigService: AppConfigService,
+        private userPreferencesService: UserPreferencesService) {
+
+        const customLanguages = appConfigService.get<Array<LanguageItem>>(AppConfigValues.APP_CONFIG_LANGUAGES_KEY);
+        this.setLanguages(customLanguages);
+    }
+
+    changeLanguage(language: LanguageItem) {
+        this.userPreferencesService.locale = language.key;
+        this.userPreferencesService.set('textOrientation', language.direction || 'ltr');
+    }
+
+    setLanguages(items: LanguageItem[]) {
+        if (items && items.length > 0) {
+            this.languages.next(items);
+        }
+    }
+}