michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0:  * You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: "use strict";
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = ["DirectoryLinksProvider"];
michael@0: 
michael@0: const Ci = Components.interfaces;
michael@0: const Cc = Components.classes;
michael@0: const Cu = Components.utils;
michael@0: 
michael@0: Cu.import("resource://gre/modules/XPCOMUtils.jsm");
michael@0: Cu.import("resource://gre/modules/Services.jsm");
michael@0: 
michael@0: XPCOMUtils.defineLazyModuleGetter(this, "NetUtil",
michael@0:   "resource://gre/modules/NetUtil.jsm");
michael@0: 
michael@0: /**
michael@0:  * Gets the currently selected locale for display.
michael@0:  * @return  the selected locale or "en-US" if none is selected
michael@0:  */
michael@0: function getLocale() {
michael@0:   let matchOS;
michael@0:   try {
michael@0:     matchOS = Services.prefs.getBoolPref(PREF_MATCH_OS_LOCALE);
michael@0:   }
michael@0:   catch (e) {}
michael@0: 
michael@0:   if (matchOS) {
michael@0:     return Services.locale.getLocaleComponentForUserAgent();
michael@0:   }
michael@0: 
michael@0:   try {
michael@0:     let locale = Services.prefs.getComplexValue(PREF_SELECTED_LOCALE,
michael@0:                                                 Ci.nsIPrefLocalizedString);
michael@0:     if (locale) {
michael@0:       return locale.data;
michael@0:     }
michael@0:   }
michael@0:   catch (e) {}
michael@0: 
michael@0:   try {
michael@0:     return Services.prefs.getCharPref(PREF_SELECTED_LOCALE);
michael@0:   }
michael@0:   catch (e) {}
michael@0: 
michael@0:   return "en-US";
michael@0: }
michael@0: 
michael@0: // The preference that tells whether to match the OS locale
michael@0: const PREF_MATCH_OS_LOCALE = "intl.locale.matchOS";
michael@0: 
michael@0: // The preference that tells what locale the user selected
michael@0: const PREF_SELECTED_LOCALE = "general.useragent.locale";
michael@0: 
michael@0: // The preference that tells where to obtain directory links
michael@0: const PREF_DIRECTORY_SOURCE = "browser.newtabpage.directorySource";
michael@0: 
michael@0: // The frecency of a directory link
michael@0: const DIRECTORY_FRECENCY = 1000;
michael@0: 
michael@0: const LINK_TYPES = Object.freeze([
michael@0:   "sponsored",
michael@0:   "affiliate",
michael@0:   "organic",
michael@0: ]);
michael@0: 
michael@0: /**
michael@0:  * Singleton that serves as the provider of directory links.
michael@0:  * Directory links are a hard-coded set of links shown if a user's link
michael@0:  * inventory is empty.
michael@0:  */
michael@0: let DirectoryLinksProvider = {
michael@0: 
michael@0:   __linksURL: null,
michael@0: 
michael@0:   _observers: [],
michael@0: 
michael@0:   get _prefs() Object.freeze({
michael@0:     linksURL: PREF_DIRECTORY_SOURCE,
michael@0:     matchOSLocale: PREF_MATCH_OS_LOCALE,
michael@0:     prefSelectedLocale: PREF_SELECTED_LOCALE,
michael@0:   }),
michael@0: 
michael@0:   get _linksURL() {
michael@0:     if (!this.__linksURL) {
michael@0:       try {
michael@0:         this.__linksURL = Services.prefs.getCharPref(this._prefs["linksURL"]);
michael@0:       }
michael@0:       catch (e) {
michael@0:         Cu.reportError("Error fetching directory links url from prefs: " + e);
michael@0:       }
michael@0:     }
michael@0:     return this.__linksURL;
michael@0:   },
michael@0: 
michael@0:   get linkTypes() LINK_TYPES,
michael@0: 
michael@0:   observe: function DirectoryLinksProvider_observe(aSubject, aTopic, aData) {
michael@0:     if (aTopic == "nsPref:changed") {
michael@0:       if (aData == this._prefs["linksURL"]) {
michael@0:         delete this.__linksURL;
michael@0:       }
michael@0:       this._callObservers("onManyLinksChanged");
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   _addPrefsObserver: function DirectoryLinksProvider_addObserver() {
michael@0:     for (let pref in this._prefs) {
michael@0:       let prefName = this._prefs[pref];
michael@0:       Services.prefs.addObserver(prefName, this, false);
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   _removePrefsObserver: function DirectoryLinksProvider_removeObserver() {
michael@0:     for (let pref in this._prefs) {
michael@0:       let prefName = this._prefs[pref];
michael@0:       Services.prefs.removeObserver(prefName, this);
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Fetches the current set of directory links.
michael@0:    * @param aCallback a callback that is provided a set of links.
michael@0:    */
michael@0:   _fetchLinks: function DirectoryLinksProvider_fetchLinks(aCallback) {
michael@0:     try {
michael@0:       NetUtil.asyncFetch(this._linksURL, (aInputStream, aResult, aRequest) => {
michael@0:         let output;
michael@0:         if (Components.isSuccessCode(aResult)) {
michael@0:           try {
michael@0:             let json = NetUtil.readInputStreamToString(aInputStream,
michael@0:                                                        aInputStream.available(),
michael@0:                                                        {charset: "UTF-8"});
michael@0:             let locale = getLocale();
michael@0:             output = JSON.parse(json)[locale];
michael@0:           }
michael@0:           catch (e) {
michael@0:             Cu.reportError(e);
michael@0:           }
michael@0:         }
michael@0:         else {
michael@0:           Cu.reportError(new Error("the fetch of " + this._linksURL + "was unsuccessful"));
michael@0:         }
michael@0:         aCallback(output || []);
michael@0:       });
michael@0:     }
michael@0:     catch (e) {
michael@0:       Cu.reportError(e);
michael@0:       aCallback([]);
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Gets the current set of directory links.
michael@0:    * @param aCallback The function that the array of links is passed to.
michael@0:    */
michael@0:   getLinks: function DirectoryLinksProvider_getLinks(aCallback) {
michael@0:     this._fetchLinks(rawLinks => {
michael@0:       // all directory links have a frecency of DIRECTORY_FRECENCY
michael@0:       aCallback(rawLinks.map((link, position) => {
michael@0:         link.frecency = DIRECTORY_FRECENCY;
michael@0:         link.lastVisitDate = rawLinks.length - position;
michael@0:         return link;
michael@0:       }));
michael@0:     });
michael@0:   },
michael@0: 
michael@0:   init: function DirectoryLinksProvider_init() {
michael@0:     this._addPrefsObserver();
michael@0:   },
michael@0: 
michael@0:   /**
michael@0:    * Return the object to its pre-init state
michael@0:    */
michael@0:   reset: function DirectoryLinksProvider_reset() {
michael@0:     delete this.__linksURL;
michael@0:     this._removePrefsObserver();
michael@0:     this._removeObservers();
michael@0:   },
michael@0: 
michael@0:   addObserver: function DirectoryLinksProvider_addObserver(aObserver) {
michael@0:     this._observers.push(aObserver);
michael@0:   },
michael@0: 
michael@0:   _callObservers: function DirectoryLinksProvider__callObservers(aMethodName, aArg) {
michael@0:     for (let obs of this._observers) {
michael@0:       if (typeof(obs[aMethodName]) == "function") {
michael@0:         try {
michael@0:           obs[aMethodName](this, aArg);
michael@0:         } catch (err) {
michael@0:           Cu.reportError(err);
michael@0:         }
michael@0:       }
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   _removeObservers: function() {
michael@0:     while (this._observers.length) {
michael@0:       this._observers.pop();
michael@0:     }
michael@0:   }
michael@0: };