/* 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/. */

/* import-globals-from extensionControlled.js */
/* import-globals-from preferences.js */
/* import-globals-from main.js */

// HOME PAGE

ChromeUtils.defineESModuleGetters(this, {
  ExtensionUtils: "resource://gre/modules/ExtensionUtils.sys.mjs",
});

/*
 * Preferences:
 *
 * browser.startup.homepage
 * - the user's home page, as a string; if the home page is a set of tabs,
 *   this will be those URLs separated by the pipe character "|"
 * browser.newtabpage.enabled
 * - determines that is shown on the user's new tab page.
 *   true = Activity Stream is shown,
 *   false = about:blank is shown
 */

Preferences.addAll([
  { id: "browser.startup.homepage", type: "wstring" },
  { id: "pref.browser.homepage.disable_button.current_page", type: "bool" },
  { id: "pref.browser.homepage.disable_button.bookmark_page", type: "bool" },
  { id: "pref.browser.homepage.disable_button.restore_default", type: "bool" },
  { id: "browser.newtabpage.enabled", type: "bool" },
]);

const HOMEPAGE_OVERRIDE_KEY = "homepage_override";
const URL_OVERRIDES_TYPE = "url_overrides";
const NEW_TAB_KEY = "newTabURL";

const BLANK_HOMEPAGE_URL = "chrome://browser/content/blanktab.html";

// New Prefs UI: we need to check for this setting before registering prefs
// so that old-style prefs continue working
if (Services.prefs.getBoolPref("browser.settings-redesign.enabled")) {
  Preferences.addAll([
    { id: "browser.newtabpage.activity-stream.showSearch", type: "bool" },
    {
      id: "browser.newtabpage.activity-stream.system.showWeather",
      type: "bool",
    },
    { id: "browser.newtabpage.activity-stream.showWeather", type: "bool" },
    {
      id: "browser.newtabpage.activity-stream.widgets.system.enabled",
      type: "bool",
    },
    {
      id: "browser.newtabpage.activity-stream.widgets.enabled",
      type: "bool",
    },
    {
      id: "browser.newtabpage.activity-stream.widgets.system.lists.enabled",
      type: "bool",
    },
    {
      id: "browser.newtabpage.activity-stream.widgets.lists.enabled",
      type: "bool",
    },
    {
      id: "browser.newtabpage.activity-stream.widgets.system.focusTimer.enabled",
      type: "bool",
    },
    {
      id: "browser.newtabpage.activity-stream.widgets.focusTimer.enabled",
      type: "bool",
    },
    {
      id: "browser.newtabpage.activity-stream.feeds.topsites",
      type: "bool",
    },
    {
      id: "browser.newtabpage.activity-stream.topSitesRows",
      type: "int",
    },
    {
      id: "browser.newtabpage.activity-stream.feeds.system.topstories",
      type: "bool",
    },
    {
      id: "browser.newtabpage.activity-stream.feeds.section.topstories",
      type: "bool",
    },
    {
      id: "browser.newtabpage.activity-stream.showSponsoredCheckboxes",
      type: "bool",
    },
    {
      id: "browser.newtabpage.activity-stream.showSponsoredTopSites",
      type: "bool",
    },
    {
      id: "browser.newtabpage.activity-stream.showSponsored",
      type: "bool",
    },
    {
      id: "browser.newtabpage.activity-stream.feeds.section.highlights",
      type: "bool",
    },
    {
      id: "browser.newtabpage.activity-stream.section.highlights.rows",
      type: "int",
    },
    {
      id: "browser.newtabpage.activity-stream.section.highlights.includeVisited",
      type: "bool",
    },
    {
      id: "browser.newtabpage.activity-stream.section.highlights.includeBookmarks",
      type: "bool",
    },
    {
      id: "browser.newtabpage.activity-stream.section.highlights.includeDownloads",
      type: "bool",
    },
  ]);

  // Search
  Preferences.addSetting({
    id: "webSearch",
    pref: "browser.newtabpage.activity-stream.showSearch",
  });

  // Weather
  Preferences.addSetting({
    id: "showWeather",
    pref: "browser.newtabpage.activity-stream.system.showWeather",
  });
  Preferences.addSetting({
    id: "weather",
    pref: "browser.newtabpage.activity-stream.showWeather",
    deps: ["showWeather"],
    visible: ({ showWeather }) => showWeather.value,
  });

  // Widgets: general
  Preferences.addSetting({
    id: "widgetsEnabled",
    pref: "browser.newtabpage.activity-stream.widgets.system.enabled",
  });
  Preferences.addSetting({
    id: "widgets",
    pref: "browser.newtabpage.activity-stream.widgets.enabled",
    deps: ["widgetsEnabled"],
    visible: ({ widgetsEnabled }) => widgetsEnabled.value,
  });

  // Widgets: lists
  Preferences.addSetting({
    id: "listsEnabled",
    pref: "browser.newtabpage.activity-stream.widgets.system.lists.enabled",
  });
  Preferences.addSetting({
    id: "lists",
    pref: "browser.newtabpage.activity-stream.widgets.lists.enabled",
    deps: ["listsEnabled"],
    visible: ({ listsEnabled }) => listsEnabled.value,
  });

  // Widgets: timer
  Preferences.addSetting({
    id: "timerEnabled",
    pref: "browser.newtabpage.activity-stream.widgets.system.focusTimer.enabled",
  });
  Preferences.addSetting({
    id: "timer",
    pref: "browser.newtabpage.activity-stream.widgets.focusTimer.enabled",
    deps: ["timerEnabled"],
    visible: ({ timerEnabled }) => timerEnabled.value,
  });

  // Shortcuts
  Preferences.addSetting({
    id: "shortcuts",
    pref: "browser.newtabpage.activity-stream.feeds.topsites",
  });
  Preferences.addSetting({
    id: "shortcutsRows",
    pref: "browser.newtabpage.activity-stream.topSitesRows",
  });

  // Stories
  Preferences.addSetting({
    id: "stories",
    pref: "browser.newtabpage.activity-stream.feeds.section.topstories",
  });

  // Dependency prefs for sponsored stories visibility
  Preferences.addSetting({
    id: "systemTopstories",
    pref: "browser.newtabpage.activity-stream.feeds.system.topstories",
  });
  Preferences.addSetting({
    id: "sectionTopstories",
    pref: "browser.newtabpage.activity-stream.feeds.section.topstories",
  });

  // Support Firefox: sponsored content
  Preferences.addSetting({
    id: "supportFirefox",
    pref: "browser.newtabpage.activity-stream.showSponsoredCheckboxes",
    deps: ["sponsoredShortcuts", "sponsoredStories"],
    onUserChange(value, { sponsoredShortcuts, sponsoredStories }) {
      // When supportFirefox changes, automatically update child preferences to match
      sponsoredShortcuts.value = !!value;
      sponsoredStories.value = !!value;
    },
  });
  Preferences.addSetting({
    id: "topsitesEnabled",
    pref: "browser.newtabpage.activity-stream.feeds.topsites",
  });
  Preferences.addSetting({
    id: "sponsoredShortcuts",
    pref: "browser.newtabpage.activity-stream.showSponsoredTopSites",
    deps: ["topsitesEnabled"],
    disabled: ({ topsitesEnabled }) => !topsitesEnabled.value,
  });
  Preferences.addSetting({
    id: "sponsoredStories",
    pref: "browser.newtabpage.activity-stream.showSponsored",
    deps: ["systemTopstories", "sectionTopstories"],
    visible: ({ systemTopstories }) => !!systemTopstories.value,
    disabled: ({ sectionTopstories }) => !sectionTopstories.value,
  });
  Preferences.addSetting({
    id: "supportFirefoxPromo",
    deps: ["supportFirefox"],
  });

  // Recent activity
  Preferences.addSetting({
    id: "recentActivity",
    pref: "browser.newtabpage.activity-stream.feeds.section.highlights",
  });
  Preferences.addSetting({
    id: "recentActivityRows",
    pref: "browser.newtabpage.activity-stream.section.highlights.rows",
  });
  Preferences.addSetting({
    id: "recentActivityVisited",
    pref: "browser.newtabpage.activity-stream.section.highlights.includeVisited",
  });
  Preferences.addSetting({
    id: "recentActivityBookmarks",
    pref: "browser.newtabpage.activity-stream.section.highlights.includeBookmarks",
  });
  Preferences.addSetting({
    id: "recentActivityDownloads",
    pref: "browser.newtabpage.activity-stream.section.highlights.includeDownloads",
  });
}

var gHomePane = {
  HOME_MODE_FIREFOX_HOME: "0",
  HOME_MODE_BLANK: "1",
  HOME_MODE_CUSTOM: "2",
  HOMEPAGE_PREF: "browser.startup.homepage",
  NEWTAB_ENABLED_PREF: "browser.newtabpage.enabled",
  ACTIVITY_STREAM_PREF_BRANCH: "browser.newtabpage.activity-stream.",

  get homePanePrefs() {
    return Preferences.getAll().filter(pref =>
      pref.id.includes(this.ACTIVITY_STREAM_PREF_BRANCH)
    );
  },

  get isPocketNewtabEnabled() {
    const value = Services.prefs.getStringPref(
      "browser.newtabpage.activity-stream.discoverystream.config",
      ""
    );
    if (value) {
      try {
        return JSON.parse(value).enabled;
      } catch (e) {
        console.error("Failed to parse Discovery Stream pref.");
      }
    }

    return false;
  },

  async syncToNewTabPref() {
    let menulist = document.getElementById("newTabMode");

    if (["0", "1"].includes(menulist.value)) {
      let newtabEnabledPref = Services.prefs.getBoolPref(
        this.NEWTAB_ENABLED_PREF,
        true
      );
      let newValue = menulist.value !== this.HOME_MODE_BLANK;
      // Only set this if the pref has changed, otherwise the pref change will trigger other listeners to repeat.
      if (newtabEnabledPref !== newValue) {
        Services.prefs.setBoolPref(this.NEWTAB_ENABLED_PREF, newValue);
      }
      let selectedAddon = ExtensionSettingsStore.getSetting(
        URL_OVERRIDES_TYPE,
        NEW_TAB_KEY
      );
      if (selectedAddon) {
        ExtensionSettingsStore.select(null, URL_OVERRIDES_TYPE, NEW_TAB_KEY);
      }
    } else {
      let addon = await AddonManager.getAddonByID(menulist.value);
      if (addon && addon.isActive) {
        ExtensionSettingsStore.select(
          addon.id,
          URL_OVERRIDES_TYPE,
          NEW_TAB_KEY
        );
      }
    }
  },

  async syncFromNewTabPref() {
    let menulist = document.getElementById("newTabMode");

    // If the new tab url was changed to about:blank or about:newtab
    if (
      AboutNewTab.newTabURL === "about:newtab" ||
      AboutNewTab.newTabURL === "about:blank" ||
      AboutNewTab.newTabURL === BLANK_HOMEPAGE_URL
    ) {
      let newtabEnabledPref = Services.prefs.getBoolPref(
        this.NEWTAB_ENABLED_PREF,
        true
      );
      let newValue = newtabEnabledPref
        ? this.HOME_MODE_FIREFOX_HOME
        : this.HOME_MODE_BLANK;
      if (newValue !== menulist.value) {
        menulist.value = newValue;
      }
      menulist.disabled = Preferences.get(this.NEWTAB_ENABLED_PREF).locked;
      // If change was triggered by installing an addon we need to update
      // the value of the menulist to be that addon.
    } else {
      let selectedAddon = ExtensionSettingsStore.getSetting(
        URL_OVERRIDES_TYPE,
        NEW_TAB_KEY
      );
      if (selectedAddon && menulist.value !== selectedAddon.id) {
        menulist.value = selectedAddon.id;
      }
    }
  },

  /**
   *  _updateMenuInterface: adds items to or removes them from the menulists
   *
   * @param {string} selectId Optional Id of the menulist to add or remove items from.
   *                          If not included this will update both home and newtab menus.
   */
  async _updateMenuInterface(selectId) {
    let selects;
    if (selectId) {
      selects = [document.getElementById(selectId)];
    } else {
      let newTabSelect = document.getElementById("newTabMode");
      let homeSelect = document.getElementById("homeMode");
      selects = [homeSelect, newTabSelect];
    }

    for (let select of selects) {
      // Remove addons from the menu popup which are no longer installed, or disabled.
      // let menuOptions = select.menupopup.childNodes;
      let menuOptions = Array.from(select.menupopup.childNodes);

      for (let option of menuOptions) {
        // If the value is not a number, assume it is an addon ID
        if (!/^\d+$/.test(option.value)) {
          let addon = await AddonManager.getAddonByID(option.value);
          if (option && (!addon || !addon.isActive)) {
            option.remove();
          }
        }
      }

      let extensionOptions;
      await ExtensionSettingsStore.initialize();
      if (select.id === "homeMode") {
        extensionOptions = ExtensionSettingsStore.getAllSettings(
          PREF_SETTING_TYPE,
          HOMEPAGE_OVERRIDE_KEY
        );
      } else {
        extensionOptions = ExtensionSettingsStore.getAllSettings(
          URL_OVERRIDES_TYPE,
          NEW_TAB_KEY
        );
      }
      let addons = await AddonManager.getAddonsByIDs(
        extensionOptions.map(a => a.id)
      );

      // Add addon options to the menu popups
      let menupopup = select.querySelector("menupopup");
      for (let addon of addons) {
        if (!addon || !addon.id || !addon.isActive) {
          continue;
        }
        let currentOption = select.querySelector(
          `[value="${CSS.escape(addon.id)}"]`
        );
        if (!currentOption) {
          let option = document.createXULElement("menuitem");
          option.value = addon.id;
          option.label = addon.name;
          menupopup.append(option);
        }
        let setting = extensionOptions.find(o => o.id == addon.id);
        if (
          (select.id === "homeMode" && setting.value == HomePage.get()) ||
          (select.id === "newTabMode" && setting.value == AboutNewTab.newTabURL)
        ) {
          select.value = addon.id;
        }
      }
    }
  },

  /**
   * watchNewTab: Listen for changes to the new tab url and enable/disable appropriate
   * areas of the UI.
   */
  watchNewTab() {
    let newTabObserver = () => {
      this.syncFromNewTabPref();
      this._updateMenuInterface("newTabMode");
    };
    Services.obs.addObserver(newTabObserver, "newtab-url-changed");
    window.addEventListener("unload", () => {
      Services.obs.removeObserver(newTabObserver, "newtab-url-changed");
    });
  },

  /**
   * watchHomePrefChange: Listen for preferences changes on the Home Tab in order to
   * show the appropriate home menu selection.
   */
  watchHomePrefChange() {
    const homePrefObserver = (subject, topic, data) => {
      // only update this UI if it is exactly the HOMEPAGE_PREF, not other prefs with the same root.
      if (data && data != this.HOMEPAGE_PREF) {
        return;
      }
      this._updateUseCurrentButton();
      this._renderCustomSettings();
      this._handleHomePageOverrides();
      this._updateMenuInterface("homeMode");
    };

    Services.prefs.addObserver(this.HOMEPAGE_PREF, homePrefObserver);
    window.addEventListener("unload", () => {
      Services.prefs.removeObserver(this.HOMEPAGE_PREF, homePrefObserver);
    });
  },

  /**
   * Listen extension changes on the New Tab and Home Tab
   * in order to update the UI and show or hide the Restore Defaults button.
   */
  watchExtensionPrefChange() {
    const extensionSettingChanged = (evt, setting) => {
      if (setting.key == "homepage_override" && setting.type == "prefs") {
        this._updateMenuInterface("homeMode");
      } else if (
        setting.key == "newTabURL" &&
        setting.type == "url_overrides"
      ) {
        this._updateMenuInterface("newTabMode");
      }
    };

    Management.on("extension-setting-changed", extensionSettingChanged);
    window.addEventListener("unload", () => {
      Management.off("extension-setting-changed", extensionSettingChanged);
    });
  },

  /**
   * Listen for all preferences changes on the Home Tab in order to show or
   * hide the Restore Defaults button.
   */
  watchHomeTabPrefChange() {
    const observer = () => this.toggleRestoreDefaultsBtn();
    Services.prefs.addObserver(this.ACTIVITY_STREAM_PREF_BRANCH, observer);
    Services.prefs.addObserver(this.HOMEPAGE_PREF, observer);
    Services.prefs.addObserver(this.NEWTAB_ENABLED_PREF, observer);

    window.addEventListener("unload", () => {
      Services.prefs.removeObserver(this.ACTIVITY_STREAM_PREF_BRANCH, observer);
      Services.prefs.removeObserver(this.HOMEPAGE_PREF, observer);
      Services.prefs.removeObserver(this.NEWTAB_ENABLED_PREF, observer);
    });
  },

  /**
   * _renderCustomSettings: Hides or shows the UI for setting a custom
   * homepage URL
   *
   * @param {obj} options
   * @param {bool} options.shouldShow Should the custom UI be shown?
   * @param {bool} options.isControlled Is an extension controlling the home page?
   */
  _renderCustomSettings(options = {}) {
    let { shouldShow, isControlled } = options;
    const customSettingsContainerEl = document.getElementById("customSettings");
    const customUrlEl = document.getElementById("homePageUrl");
    const homePage = HomePage.get();
    const isHomePageCustom =
      (!this._isHomePageDefaultValue() &&
        !this.isHomePageBlank() &&
        !isControlled) ||
      homePage.locked;

    if (typeof shouldShow === "undefined") {
      shouldShow = isHomePageCustom;
    }
    customSettingsContainerEl.hidden = !shouldShow;

    // We can't use isHomePageDefaultValue and isHomePageBlank here because we want to disregard the blank
    // possibility triggered by the browser.startup.page being 0.
    // We also skip when HomePage is locked because it might be locked to a default that isn't "about:home"
    // (and it makes existing tests happy).
    let newValue;
    if (
      this._isBlankPage(homePage) ||
      (HomePage.isDefault && !HomePage.locked)
    ) {
      newValue = "";
    } else {
      newValue = homePage;
    }
    if (customUrlEl.value !== newValue) {
      customUrlEl.value = newValue;
    }
  },

  /**
   * _isHomePageDefaultValue
   *
   * @returns {bool} Is the homepage set to the default pref value?
   */
  _isHomePageDefaultValue() {
    const startupPref = Preferences.get("browser.startup.page");
    return (
      startupPref.value !== gMainPane.STARTUP_PREF_BLANK && HomePage.isDefault
    );
  },

  /**
   * isHomePageBlank
   *
   * @returns {bool} Is the homepage set to about:blank?
   */
  isHomePageBlank() {
    const startupPref = Preferences.get("browser.startup.page");
    return (
      ["about:blank", BLANK_HOMEPAGE_URL, ""].includes(HomePage.get()) ||
      startupPref.value === gMainPane.STARTUP_PREF_BLANK
    );
  },

  /**
   * _isTabAboutPreferencesOrSettings: Is a given tab set to about:preferences or about:settings?
   *
   * @param {Element} aTab A tab element
   * @returns {bool} Is the linkedBrowser of aElement set to about:preferences or about:settings?
   */
  _isTabAboutPreferencesOrSettings(aTab) {
    return (
      aTab.linkedBrowser.currentURI.spec.startsWith("about:preferences") ||
      aTab.linkedBrowser.currentURI.spec.startsWith("about:settings")
    );
  },

  /**
   * _getTabsForHomePage
   *
   * @returns {Array} An array of current tabs
   */
  _getTabsForHomePage() {
    let tabs = [];
    let win = Services.wm.getMostRecentWindow("navigator:browser");

    // We should only include visible & non-pinned tabs
    if (
      win &&
      win.document.documentElement.getAttribute("windowtype") ===
        "navigator:browser"
    ) {
      tabs = win.gBrowser.visibleTabs.slice(win.gBrowser.pinnedTabCount);
      tabs = tabs.filter(tab => !this._isTabAboutPreferencesOrSettings(tab));
      // XXX: Bug 1441637 - Fix tabbrowser to report tab.closing before it blurs it
      tabs = tabs.filter(tab => !tab.closing);
    }

    return tabs;
  },

  _renderHomepageMode(controllingExtension) {
    const isDefault = this._isHomePageDefaultValue();
    const isBlank = this.isHomePageBlank();
    const el = document.getElementById("homeMode");
    let newValue;

    if (controllingExtension && controllingExtension.id) {
      newValue = controllingExtension.id;
    } else if (isDefault) {
      newValue = this.HOME_MODE_FIREFOX_HOME;
    } else if (isBlank) {
      newValue = this.HOME_MODE_BLANK;
    } else {
      newValue = this.HOME_MODE_CUSTOM;
    }
    if (el.value !== newValue) {
      el.value = newValue;
    }
  },

  _setInputDisabledStates(isControlled) {
    let tabCount = this._getTabsForHomePage().length;

    // Disable or enable the inputs based on if this is controlled by an extension.
    document
      .querySelectorAll(".check-home-page-controlled")
      .forEach(element => {
        let isDisabled;
        let pref =
          element.getAttribute("preference") ||
          element.getAttribute("data-preference-related");
        if (!pref) {
          throw new Error(
            `Element with id ${element.id} did not have preference or data-preference-related attribute defined.`
          );
        }

        if (pref === this.HOMEPAGE_PREF) {
          isDisabled = HomePage.locked;
        } else {
          isDisabled = Preferences.get(pref).locked || isControlled;
        }

        if (pref === "pref.browser.disable_button.current_page") {
          // Special case for current_page to disable it if tabCount is 0
          isDisabled = isDisabled || tabCount < 1;
        }

        element.disabled = isDisabled;
      });
  },

  async _handleHomePageOverrides() {
    let controllingExtension;
    if (HomePage.locked) {
      // Disable inputs if they are locked.
      this._renderCustomSettings();
      this._setInputDisabledStates(false);
    } else {
      if (ExtensionUtils.isExtensionUrl(HomePage.get())) {
        controllingExtension = await getControllingExtension(
          PREF_SETTING_TYPE,
          HOMEPAGE_OVERRIDE_KEY
        );
      }
      this._setInputDisabledStates();
      this._renderCustomSettings({
        isControlled: !!controllingExtension,
      });
    }
    this._renderHomepageMode(controllingExtension);
  },

  onMenuChange(event) {
    const { value } = event.target;
    const startupPref = Preferences.get("browser.startup.page");
    let selectedAddon = ExtensionSettingsStore.getSetting(
      PREF_SETTING_TYPE,
      HOMEPAGE_OVERRIDE_KEY
    );

    switch (value) {
      case this.HOME_MODE_FIREFOX_HOME:
        if (startupPref.value === gMainPane.STARTUP_PREF_BLANK) {
          startupPref.value = gMainPane.STARTUP_PREF_HOMEPAGE;
        }
        if (!HomePage.isDefault) {
          HomePage.reset();
        } else {
          this._renderCustomSettings({ shouldShow: false });
        }
        if (selectedAddon) {
          ExtensionSettingsStore.select(
            null,
            PREF_SETTING_TYPE,
            HOMEPAGE_OVERRIDE_KEY
          );
        }
        break;
      case this.HOME_MODE_BLANK:
        if (!this._isBlankPage(HomePage.get())) {
          HomePage.safeSet(BLANK_HOMEPAGE_URL);
        } else {
          this._renderCustomSettings({ shouldShow: false });
        }
        if (selectedAddon) {
          ExtensionSettingsStore.select(
            null,
            PREF_SETTING_TYPE,
            HOMEPAGE_OVERRIDE_KEY
          );
        }
        break;
      case this.HOME_MODE_CUSTOM:
        if (startupPref.value === gMainPane.STARTUP_PREF_BLANK) {
          Services.prefs.clearUserPref(startupPref.id);
        }
        if (HomePage.getDefault() != HomePage.getOriginalDefault()) {
          HomePage.clear();
        }
        this._renderCustomSettings({ shouldShow: true });
        if (selectedAddon) {
          ExtensionSettingsStore.select(
            null,
            PREF_SETTING_TYPE,
            HOMEPAGE_OVERRIDE_KEY
          );
        }
        break;
      // extensions will have a variety of values as their ID, so treat it as default
      default:
        AddonManager.getAddonByID(value).then(addon => {
          if (addon && addon.isActive) {
            ExtensionPreferencesManager.selectSetting(
              addon.id,
              HOMEPAGE_OVERRIDE_KEY
            );
          }
          this._renderCustomSettings({ shouldShow: false });
        });
    }
  },

  /**
   * Switches the "Use Current Page" button between its singular and plural
   * forms.
   */
  async _updateUseCurrentButton() {
    let useCurrent = document.getElementById("useCurrentBtn");
    let tabs = this._getTabsForHomePage();
    const tabCount = tabs.length;
    document.l10n.setAttributes(useCurrent, "use-current-pages", { tabCount });

    // If the homepage is controlled by an extension then you can't use this.
    if (
      await getControllingExtensionInfo(
        PREF_SETTING_TYPE,
        HOMEPAGE_OVERRIDE_KEY
      )
    ) {
      return;
    }

    // In this case, the button's disabled state is set by preferences.xml.
    let prefName = "pref.browser.homepage.disable_button.current_page";
    if (Preferences.get(prefName).locked) {
      return;
    }

    useCurrent.disabled = tabCount < 1;
  },

  /**
   * Sets the home page to the URL(s) of any currently opened tab(s),
   * updating about:preferences#home UI to reflect this.
   */
  setHomePageToCurrent() {
    let tabs = this._getTabsForHomePage();
    function getTabURI(t) {
      return t.linkedBrowser.currentURI.spec;
    }

    // FIXME Bug 244192: using dangerous "|" joiner!
    if (tabs.length) {
      HomePage.set(tabs.map(getTabURI).join("|")).catch(console.error);
    }
  },

  _setHomePageToBookmarkClosed(rv, aEvent) {
    if (aEvent.detail.button != "accept") {
      return;
    }
    if (rv.urls && rv.names) {
      // XXX still using dangerous "|" joiner!
      HomePage.set(rv.urls.join("|")).catch(console.error);
    }
  },

  /**
   * Displays a dialog in which the user can select a bookmark to use as home
   * page.  If the user selects a bookmark, that bookmark's name is displayed in
   * UI and the bookmark's address is stored to the home page preference.
   */
  setHomePageToBookmark() {
    const rv = { urls: null, names: null };
    gSubDialog.open(
      "chrome://browser/content/preferences/dialogs/selectBookmark.xhtml",
      {
        features: "resizable=yes, modal=yes",
        closingCallback: this._setHomePageToBookmarkClosed.bind(this, rv),
      },
      rv
    );
  },

  restoreDefaultHomePage() {
    HomePage.reset();
    this._handleHomePageOverrides();
    Services.prefs.clearUserPref(this.NEWTAB_ENABLED_PREF);
    AboutNewTab.resetNewTabURL();
  },

  onCustomHomePageChange(event) {
    const value = event.target.value || HomePage.getDefault();
    HomePage.set(value).catch(console.error);
  },

  /**
   * Check all Home Tab preferences for user set values.
   */
  _changedHomeTabDefaultPrefs() {
    // If Discovery Stream is enabled Firefox Home Content preference options are hidden
    const homeContentChanged =
      !this.isPocketNewtabEnabled &&
      this.homePanePrefs.some(pref => pref.hasUserValue);
    const newtabPref = Preferences.get(this.NEWTAB_ENABLED_PREF);
    const extensionControlled = Preferences.get(
      "browser.startup.homepage_override.extensionControlled"
    );

    return (
      homeContentChanged ||
      HomePage.overridden ||
      newtabPref.hasUserValue ||
      AboutNewTab.newTabURLOverridden ||
      extensionControlled
    );
  },

  _isBlankPage(url) {
    return url == "about:blank" || url == BLANK_HOMEPAGE_URL;
  },

  /**
   * Show the Restore Defaults button if any preference on the Home tab was
   * changed, or hide it otherwise.
   */
  toggleRestoreDefaultsBtn() {
    const btn = document.getElementById("restoreDefaultHomePageBtn");
    const prefChanged = this._changedHomeTabDefaultPrefs();
    if (prefChanged) {
      btn.style.removeProperty("visibility");
    } else {
      btn.style.visibility = "hidden";
    }
  },

  /**
   * Set all prefs on the Home tab back to their default values.
   */
  restoreDefaultPrefsForHome() {
    this.restoreDefaultHomePage();
    // If Discovery Stream is enabled Firefox Home Content preference options are hidden
    if (!this.isPocketNewtabEnabled) {
      this.homePanePrefs.forEach(pref => Services.prefs.clearUserPref(pref.id));
    }
  },

  init() {
    initSettingGroup("home");

    // Event Listeners
    document
      .getElementById("homePageUrl")
      .addEventListener("change", this.onCustomHomePageChange.bind(this));
    document
      .getElementById("useCurrentBtn")
      .addEventListener("command", this.setHomePageToCurrent.bind(this));
    document
      .getElementById("useBookmarkBtn")
      .addEventListener("command", this.setHomePageToBookmark.bind(this));
    document
      .getElementById("restoreDefaultHomePageBtn")
      .addEventListener("command", this.restoreDefaultPrefsForHome.bind(this));

    // Setup the add-on options for the new tab section before registering the
    // listener.
    this._updateMenuInterface();
    document
      .getElementById("newTabMode")
      .addEventListener("command", this.syncToNewTabPref.bind(this));
    document
      .getElementById("homeMode")
      .addEventListener("command", this.onMenuChange.bind(this));

    this._updateUseCurrentButton();
    this._handleHomePageOverrides();
    this.syncFromNewTabPref();
    window.addEventListener("focus", this._updateUseCurrentButton.bind(this));

    // Extension/override-related events
    this.watchNewTab();
    this.watchHomePrefChange();
    this.watchExtensionPrefChange();
    this.watchHomeTabPrefChange();
    // Notify observers that the UI is now ready
    Services.obs.notifyObservers(window, "home-pane-loaded");
  },
};
