MD Settings: Languages model for language pages

chrome/browser/resources/settings/languages_page/manage_languages_page.js

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @fileoverview 'cr-settings-manage-languages-page' is a sub-page for enabling
+ * and disabling langauges.
+ *
+ * @group Chrome Settings Elements
+ * @element cr-settings-manage-languages-page
+ */
+Polymer({
+  is: 'cr-settings-manage-languages-page',
+
+  properties: {
+    /**
+     * Preferences state.
+     */
+    prefs: {
+      type: Object,
+      notify: true,
+    },
+
+    /**
+     * @type {(LanguagesModel|undefined)}
+     */
+    model: {
+      type: Object,
+      notify: true,
+    },
+
+    /** @type {(Array<{code: string, displayName: string, enabled: boolean}>|
+     *          undefined)}
+     * @private
+     */
+    availableLanguages_: Array,
+  },
+
+  observers: [
+    'enabledLanguagesChanged_(model.enabledLanguages.*)',
+  ],
+
+  /** @private */
+  onBackTap_: function() {
+    this.$.pages.back();
+  },
+
+  /**
+   * Handler for removing a language.
+   * @param {!{model: {item: {language: {code: string}}}}} e
+   */
+  onRemoveLanguageTap_: function(e) {
+    this.$.languages.disableLanguage(e.model.item.language.code);
+  },
+
+  /**
+   * Handler for adding a language.
+   * @param {!{model: {item: {code: string}}}} e
+   */
+  onAddLanguageTap_: function(e) {
+    this.$.languages.enableLanguage(e.model.item.code);
+  },
+
+  /**
+   * True if a language is not the prospective UI language or the last remaining
+   * language.
+   * @param {string} languageCode
+   * @param {!Array<!LanguageInfo>} enableLanguage
+   * @return {boolean}
+   */
+  canRemoveLanguage_: function(languageCode, enabledLanguages) {
+    var appLocale = this.prefs.intl.app_locale.value || navigator.language;
+    if (languageCode == appLocale)
+      return false;
+    if (enabledLanguages.length == 1)
+      return false;
+    return true;
+  },
+
+  /**
+   * Updates the available languages to be bound to the iron-list.
+   * TODO(michaelpg): Update properties of individual items instead of
+   *     rebuilding entire list.
+   */
+  enabledLanguagesChanged_: function() {
+    var availableLanguages = [];
+    for (var i = 0; i < this.model.supportedLanguages.length; i++) {
+      var language = this.model.supportedLanguages[i];
+      availableLanguages.push({
+        code: language.code,
+        displayName: language.displayName,
+        enabled: !!this.model.enabledLanguageMap[language.code],
+      });
+    }
+    this.availableLanguages_ = availableLanguages;
+  },
+});