Mypal68/browser/base/content/browser-sync.js

/* 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/. */

// This file is loaded into the browser window scope.
/* eslint-env mozilla/browser-window */

const { UIState } = ChromeUtils.import("resource://services-sync/UIState.jsm");

ChromeUtils.defineModuleGetter(
  this,
  "FxAccounts",
  "resource://gre/modules/FxAccounts.jsm"
);
ChromeUtils.defineModuleGetter(
  this,
  "EnsureFxAccountsWebChannel",
  "resource://gre/modules/FxAccountsWebChannel.jsm"
);
ChromeUtils.defineModuleGetter(
  this,
  "Weave",
  "resource://services-sync/main.js"
);

const MIN_STATUS_ANIMATION_DURATION = 1600;

const FXA_NO_AVATAR_ZEROS = "00000000000000000000000000000000";

var gSync = {
  _initialized: false,
  // The last sync start time. Used to calculate the leftover animation time
  // once syncing completes (bug 1239042).
  _syncStartTime: 0,
  _syncAnimationTimer: 0,

  _obs: ["weave:engine:sync:finish", "quit-application", UIState.ON_UPDATE],

  get fxaStrings() {
    delete this.fxaStrings;
    return (this.fxaStrings = Services.strings.createBundle(
      "chrome://browser/locale/accounts.properties"
    ));
  },

  get syncStrings() {
    delete this.syncStrings;
    // XXXzpao these strings should probably be moved from /services to /browser... (bug 583381)
    //        but for now just make it work
    return (this.syncStrings = Services.strings.createBundle(
      "chrome://weave/locale/sync.properties"
    ));
  },

  get syncReady() {
    return Cc["@mozilla.org/weave/service;1"].getService().wrappedJSObject
      .ready;
  },

  // Returns true if sync is configured but hasn't loaded or the send tab
  // targets list isn't ready yet.
  get sendTabConfiguredAndLoading() {
    return (
      UIState.get().status == UIState.STATUS_SIGNED_IN &&
      (!this.syncReady || !Weave.Service.clientsEngine.hasSyncedThisSession)
    );
  },

  get isSignedIn() {
    return UIState.get().status == UIState.STATUS_SIGNED_IN;
  },

  get sendTabTargets() {
    return Weave.Service.clientsEngine.fxaDevices
      .sort((a, b) => a.name.localeCompare(b.name))
      .filter(
        d =>
          !d.isCurrentDevice &&
          (fxAccounts.commands.sendTab.isDeviceCompatible(d) || d.clientRecord)
      );
  },

  get offline() {
    return Weave.Service.scheduler.offline;
  },

  _generateNodeGetters() {
    for (let k of ["Status", "Avatar", "Label", "Container"]) {
      let prop = "appMenu" + k;
      let suffix = k.toLowerCase();
      delete this[prop];
      this.__defineGetter__(prop, function() {
        delete this[prop];
        return (this[prop] = document.getElementById("appMenu-fxa-" + suffix));
      });
    }
  },

  _definePrefGetters() {
    XPCOMUtils.defineLazyPreferenceGetter(
      this,
      "UNSENDABLE_URL_REGEXP",
      "services.sync.engine.tabs.filteredUrls",
      null,
      null,
      rx => {
        try {
          return new RegExp(rx, "i");
        } catch (e) {
          Cu.reportError(
            `Failed to build url filter regexp for send tab: ${e}`
          );
          return null;
        }
      }
    );
    XPCOMUtils.defineLazyPreferenceGetter(
      this,
      "PRODUCT_INFO_BASE_URL",
      "app.productInfo.baseURL"
    );
    XPCOMUtils.defineLazyPreferenceGetter(
      this,
      "SYNC_ENABLED",
      "identity.fxaccounts.enabled"
    );
  },

  maybeUpdateUIState() {
    // Update the UI.
    if (UIState.isReady()) {
      const state = UIState.get();
      // If we are not configured, the UI is already in the right state when
      // we open the window. We can avoid a repaint.
      if (state.status != UIState.STATUS_NOT_CONFIGURED) {
        this.updateAllUI(state);
      }
    }
  },

  init() {
    if (this._initialized) {
      return;
    }

    this._definePrefGetters();

    if (!this.SYNC_ENABLED) {
      this.onSyncDisabled();
      return;
    }

    MozXULElement.insertFTLIfNeeded("browser/sync.ftl");

    this._generateNodeGetters();

    // Label for the sync buttons.
    if (!this.appMenuLabel) {
      // We are in a window without our elements - just abort now, without
      // setting this._initialized, so we don't attempt to remove observers.
      return;
    }
    // We start with every menuitem hidden (except for the "setup sync" state),
    // so that we don't need to init the sync UI on windows like pageInfo.xhtml
    // (see bug 1384856).
    // maybeUpdateUIState() also optimizes for this - if we should be in the
    // "setup sync" state, that function assumes we are already in it and
    // doesn't re-initialize the UI elements.
    document.getElementById("sync-setup").hidden = false;
    document.getElementById("PanelUI-remotetabs-setupsync").hidden = false;

    for (let topic of this._obs) {
      Services.obs.addObserver(this, topic, true);
    }

    this.maybeUpdateUIState();

    EnsureFxAccountsWebChannel();

    this._initialized = true;
  },

  uninit() {
    if (!this._initialized) {
      return;
    }

    for (let topic of this._obs) {
      Services.obs.removeObserver(this, topic);
    }

    this._initialized = false;
  },

  observe(subject, topic, data) {
    if (!this._initialized) {
      Cu.reportError("browser-sync observer called after unload: " + topic);
      return;
    }
    switch (topic) {
      case UIState.ON_UPDATE:
        const state = UIState.get();
        this.updateAllUI(state);
        break;
      case "quit-application":
        // Stop the animation timer on shutdown, since we can't update the UI
        // after this.
        clearTimeout(this._syncAnimationTimer);
        break;
      case "weave:engine:sync:finish":
        if (data != "clients") {
          return;
        }
        this.onClientsSynced();
        break;
    }
  },

  updateAllUI(state) {
    this.updatePanelPopup(state);
    this.updateState(state);
    this.updateSyncButtonsTooltip(state);
    this.updateSyncStatus(state);
    this.updateFxAPanel(state);
  },

  updateSendToDeviceTitle() {
    let string = gBrowserBundle.GetStringFromName("sendTabsToDevice.label");
    let title = PluralForm.get(1, string).replace("#1", 1);
    if (gBrowser.selectedTab.multiselected) {
      let tabCount = gBrowser.selectedTabs.length;
      title = PluralForm.get(tabCount, string).replace("#1", tabCount);
    }

    document
      .getElementById("PanelUI-fxa-menu-sendtab-button")
      .setAttribute("label", title);
  },

  showSendToDeviceView(anchor) {
    PanelUI.showSubView("PanelUI-sendTabToDevice", anchor);
    let panelViewNode = document.getElementById("PanelUI-sendTabToDevice");
    this.populateSendTabToDevicesView(
      panelViewNode,
      this.populateSendTabToDevicesView.bind(this)
    );
  },

  showSendToDeviceViewFromFxaMenu(anchor) {
    this.showSendToDeviceView(anchor);
    this.emitFxaToolbarTelemetry("send_tab", anchor);
  },

  showRemoteTabsFromFxaMenu(panel) {
    PanelUI.showSubView("PanelUI-remotetabs", panel);
    this.emitFxaToolbarTelemetry("sync_tabs", panel);
  },

  showSidebarFromFxaMenu(panel) {
    SidebarUI.toggle("viewTabsSidebar");
    this.emitFxaToolbarTelemetry("sync_tabs_sidebar", panel);
  },

  populateSendTabToDevicesView(panelViewNode, reloadFunc) {
    let bodyNode = panelViewNode.querySelector(".panel-subview-body");
    let panelNode = panelViewNode.closest("panel");
    let browser = gBrowser.selectedBrowser;
    let url = browser.currentURI.spec;
    let title = browser.contentTitle;
    let multiselected = gBrowser.selectedTab.multiselected;

    // This is on top because it also clears the device list between state
    // changes.
    this.populateSendTabToDevicesMenu(
      bodyNode,
      url,
      title,
      multiselected,
      (clientId, name, clientType, lastModified) => {
        if (!name) {
          return document.createXULElement("toolbarseparator");
        }
        let item = document.createXULElement("toolbarbutton");
        item.classList.add("pageAction-sendToDevice-device", "subviewbutton");
        if (clientId) {
          item.classList.add("subviewbutton-iconic");
          if (lastModified) {
            item.setAttribute(
              "tooltiptext",
              gSync.formatLastSyncDate(lastModified)
            );
          }
        }

        item.addEventListener("command", event => {
          if (panelNode) {
            PanelMultiView.hidePopup(panelNode);
          }
          // There are items in the subview that don't represent devices: "Sign
          // in", "Learn about Sync", etc.  Device items will be .sendtab-target.
          if (event.target.classList.contains("sendtab-target")) {
            let action = PageActions.actionForID("sendToDevice");
            let messageId = gSync.offline && "sendToDeviceOffline";
            showBrowserPageActionFeedback(action, event, messageId);
          }
        });
        return item;
      }
    );

    bodyNode.removeAttribute("state");
    // In the first ~10 sec after startup, Sync may not be loaded and the list
    // of devices will be empty.
    if (gSync.sendTabConfiguredAndLoading) {
      bodyNode.setAttribute("state", "notready");
      // Force a background Sync
      Services.tm.dispatchToMainThread(async () => {
        await Weave.Service.sync({ why: "pageactions", engines: [] }); // [] = clients engine only
        // There's no way Sync is still syncing at this point, but we check
        // anyway to avoid infinite looping.
        if (!window.closed && !gSync.sendTabConfiguredAndLoading) {
          reloadFunc(panelViewNode);
        }
      });
    }
  },

  toggleAccountPanel(viewId, aEvent) {
    // Don't show the panel if the window is in customization mode.
    if (document.documentElement.hasAttribute("customizing")) {
      return;
    }

    if (
      (aEvent.type == "mousedown" && aEvent.button != 0) ||
      (aEvent.type == "keypress" &&
        aEvent.charCode != KeyEvent.DOM_VK_SPACE &&
        aEvent.keyCode != KeyEvent.DOM_VK_RETURN)
    ) {
      return;
    }

    if (!gFxaToolbarAccessed) {
      Services.prefs.setBoolPref("identity.fxaccounts.toolbar.accessed", true);
      document.documentElement.removeAttribute("fxa_avatar_badged");
    }

    this.enableSendTabIfValidTab();

    const anchor = document.getElementById("fxa-toolbar-menu-button");
    if (anchor.getAttribute("open") == "true") {
      PanelUI.hide();
    } else {
      this.emitFxaToolbarTelemetry("toolbar_icon", anchor);
      PanelUI.showSubView(viewId, anchor, aEvent);
    }
  },

  updateFxAPanel(state = {}) {
    const mainWindowEl = document.documentElement;

    // The Firefox Account toolbar currently handles 3 different states for
    // users. The default `not_configured state shows an empty avatar, `unverified`
    // state shows an avatar with an email icon and the `verified` state will show
    // the users custom profile image or a filled avatar.
    let stateValue = "not_configured";
    document.getElementById("PanelUI-fxa").removeAttribute("title");
    if (
      state.status === UIState.STATUS_LOGIN_FAILED ||
      state.status === UIState.STATUS_NOT_VERIFIED
    ) {
      stateValue = "unverified";
    } else if (state.status === UIState.STATUS_SIGNED_IN) {
      stateValue = "signedin";
      // Firefox Account specifies a `default` avatar image that uses the convention
      // of all 0s in url. The default used in the design of the toolbar menu is
      // different from the one provided by Firefox Account. Perform a check and only
      // change avatar *if* this is not a default avatar.
      if (state.avatarURL && !state.avatarURL.includes(FXA_NO_AVATAR_ZEROS)) {
        // The user has specified a custom avatar, attempt to load the image on all the menu buttons.
        const bgImage = `url("${state.avatarURL}")`;
        let img = new Image();
        img.onload = () => {
          // If the image has successfully loaded, update the menu buttons else
          // we will use the default avatar image.
          mainWindowEl.style.setProperty("--avatar-image-url", bgImage);
        };
        img.onerror = () => {
          // If the image failed to load, remove the property and default
          // to standard avatar.
          mainWindowEl.style.removeProperty("--avatar-image-url");
        };
        img.src = state.avatarURL;
      } else {
        mainWindowEl.style.removeProperty("--avatar-image-url");
      }

      document.getElementById("fxa-menu-email").value = state.email;

      let defaultPanelTitle = this.fxaStrings.GetStringFromName(
        "account.title"
      );
      document
        .getElementById("PanelUI-fxa")
        .setAttribute(
          "title",
          state.displayName ? state.displayName : defaultPanelTitle
        );
    }
    mainWindowEl.setAttribute("fxastatus", stateValue);
  },

  enableSendTabIfValidTab() {
    // All tabs selected must be sendable for the Send Tab button to be enabled
    // on the FxA menu.
    let canSendAllURIs = gBrowser.selectedTabs.every(t =>
      this.isSendableURI(t.linkedBrowser.currentURI.spec)
    );

    if (canSendAllURIs) {
      document
        .getElementById("PanelUI-fxa-menu-sendtab-button")
        .removeAttribute("disabled");
    } else {
      document
        .getElementById("PanelUI-fxa-menu-sendtab-button")
        .setAttribute("disabled", true);
    }
  },

  emitFxaToolbarTelemetry(type, panel) {
    if (UIState.isReady() && panel) {
      const state = UIState.get();
      const hasAvatar =
        state.avatarURL && !state.avatarURL.includes(FXA_NO_AVATAR_ZEROS);
      let extraOptions = {
        fxa_status: state.status,
        fxa_avatar: hasAvatar ? "true" : "false",
      };

      // When the fxa avatar panel is within the Firefox app menu,
      // we emit different telemetry.
      let eventName = "fxa_avatar_menu";
      if (this.isPanelInsideAppMenu(panel)) {
        eventName = "fxa_app_menu";
      }

      Services.telemetry.recordEvent(
        eventName,
        "click",
        type,
        null,
        extraOptions
      );
    }
  },

  isPanelInsideAppMenu(panel = undefined) {
    const appMenuPanel = document.getElementById("appMenu-popup");
    if (panel && appMenuPanel.contains(panel)) {
      return true;
    }
    return false;
  },

  updatePanelPopup(state) {
    let defaultLabel = this.appMenuStatus.getAttribute("defaultlabel");
    const status = state.status;
    // Reset the status bar to its original state.
    this.appMenuLabel.setAttribute("label", defaultLabel);
    this.appMenuContainer.removeAttribute("fxastatus");
    this.appMenuAvatar.style.removeProperty("list-style-image");
    this.appMenuLabel.classList.remove("subviewbutton-nav");

    if (status == UIState.STATUS_NOT_CONFIGURED) {
      return;
    }

    // At this point we consider sync to be configured (but still can be in an error state).
    if (status == UIState.STATUS_LOGIN_FAILED) {
      let tooltipDescription = this.fxaStrings.formatStringFromName(
        "reconnectDescription",
        [state.email]
      );
      let errorLabel = this.appMenuStatus.getAttribute("errorlabel");
      this.appMenuContainer.setAttribute("fxastatus", "login-failed");
      this.appMenuLabel.setAttribute("label", errorLabel);
      this.appMenuStatus.setAttribute("tooltiptext", tooltipDescription);
      return;
    } else if (status == UIState.STATUS_NOT_VERIFIED) {
      let tooltipDescription = this.fxaStrings.formatStringFromName(
        "verifyDescription",
        [state.email]
      );
      let unverifiedLabel = this.appMenuStatus.getAttribute("unverifiedlabel");
      this.appMenuContainer.setAttribute("fxastatus", "unverified");
      this.appMenuLabel.setAttribute("label", unverifiedLabel);
      this.appMenuStatus.setAttribute("tooltiptext", tooltipDescription);
      return;
    }

    // At this point we consider sync to be logged-in.
    this.appMenuContainer.setAttribute("fxastatus", "signedin");
    this.appMenuLabel.setAttribute("label", state.displayName || state.email);
    this.appMenuLabel.classList.add("subviewbutton-nav");
    this.appMenuStatus.removeAttribute("tooltiptext");

    if (state.avatarURL) {
      let bgImage = 'url("' + state.avatarURL + '")';
      this.appMenuAvatar.style.listStyleImage = bgImage;

      let img = new Image();
      img.onerror = () => {
        // Clear the image if it has trouble loading. Since this callback is asynchronous
        // we check to make sure the image is still the same before we clear it.
        if (this.appMenuAvatar.style.listStyleImage === bgImage) {
          this.appMenuAvatar.style.removeProperty("list-style-image");
        }
      };
      img.src = state.avatarURL;
    }
  },

  updateState(state) {
    for (let [status, menuId, boxId] of [
      [
        UIState.STATUS_NOT_CONFIGURED,
        "sync-setup",
        "PanelUI-remotetabs-setupsync",
      ],
      [
        UIState.STATUS_LOGIN_FAILED,
        "sync-reauthitem",
        "PanelUI-remotetabs-reauthsync",
      ],
      [
        UIState.STATUS_NOT_VERIFIED,
        "sync-unverifieditem",
        "PanelUI-remotetabs-unverified",
      ],
      [UIState.STATUS_SIGNED_IN, "sync-syncnowitem", "PanelUI-remotetabs-main"],
    ]) {
      document.getElementById(menuId).hidden = document.getElementById(
        boxId
      ).hidden = status != state.status;
    }
  },

  updateSyncStatus(state) {
    let syncNow = document.querySelector(".syncNowBtn");
    const syncingUI = syncNow.getAttribute("syncstatus") == "active";
    if (state.syncing != syncingUI) {
      // Do we need to update the UI?
      state.syncing ? this.onActivityStart() : this.onActivityStop();
    }
  },

  onMenuPanelCommand() {
    switch (this.appMenuContainer.getAttribute("fxastatus")) {
      case "signedin":
        const panel = document.getElementById("appMenu-fxa-status");
        this.emitFxaToolbarTelemetry("toolbar_icon", panel);
        PanelUI.showSubView("PanelUI-fxa", panel);
        break;
      case "error":
        if (this.appMenuContainer.getAttribute("fxastatus") == "unverified") {
          this.openPrefs("menupanel", "fxaError");
        } else {
          this.openSignInAgainPage("menupanel");
        }
        PanelUI.hide();
        break;
      default:
        this.openPrefs("menupanel", "fxa");
        PanelUI.hide();
        break;
    }
  },

  async openSignInAgainPage(entryPoint) {
    const url = await FxAccounts.config.promiseForceSigninURI(entryPoint);
    switchToTabHavingURI(url, true, {
      replaceQueryString: true,
      triggeringPrincipal: Services.scriptSecurityManager.getSystemPrincipal(),
    });
  },

  async openDevicesManagementPage(entryPoint) {
    let url = await FxAccounts.config.promiseManageDevicesURI(entryPoint);
    switchToTabHavingURI(url, true, {
      replaceQueryString: true,
      triggeringPrincipal: Services.scriptSecurityManager.getSystemPrincipal(),
    });
  },

  async openConnectAnotherDevice(entryPoint) {
    const url = await FxAccounts.config.promiseConnectDeviceURI(entryPoint);
    openTrustedLinkIn(url, "tab");
  },

  async openConnectAnotherDeviceFromFxaMenu(panel = undefined) {
    this.emitFxaToolbarTelemetry("cad", panel);
    let entryPoint = "fxa_discoverability_native";
    if (this.isPanelInsideAppMenu(panel)) {
      entryPoint = "fxa_app_menu";
    }
    this.openConnectAnotherDevice(entryPoint);
  },

  openSendToDevicePromo() {
    let url = this.PRODUCT_INFO_BASE_URL;
    url += "send-tabs/?utm_source=" + Services.appinfo.name.toLowerCase();
    switchToTabHavingURI(url, true, { replaceQueryString: true });
  },

  async openFxAEmailFirstPage(entryPoint) {
    const url = await FxAccounts.config.promiseEmailFirstURI(entryPoint);
    switchToTabHavingURI(url, true, { replaceQueryString: true });
  },

  async openFxAEmailFirstPageFromFxaMenu(panel = undefined) {
    this.emitFxaToolbarTelemetry("login", panel);
    let entryPoint = "fxa_discoverability_native";
    if (this.isPanelInsideAppMenu(panel)) {
      entryPoint = "fxa_app_menu";
    }
    this.openFxAEmailFirstPage(entryPoint);
  },

  async openFxAManagePage(entryPoint) {
    const url = await FxAccounts.config.promiseManageURI(entryPoint);
    switchToTabHavingURI(url, true, { replaceQueryString: true });
  },

  async openFxAManagePageFromFxaMenu(panel = undefined) {
    this.emitFxaToolbarTelemetry("account_settings", panel);
    let entryPoint = "fxa_discoverability_native";
    if (this.isPanelInsideAppMenu(panel)) {
      entryPoint = "fxa_app_menu";
    }
    this.openFxAManagePage(entryPoint);
  },

  async sendTabToDevice(url, targets, title) {
    const fxaCommandsDevices = [];
    const oldSendTabClients = [];
    for (const target of targets) {
      if (fxAccounts.commands.sendTab.isDeviceCompatible(target)) {
        fxaCommandsDevices.push(target);
      } else if (target.clientRecord) {
        oldSendTabClients.push(target.clientRecord);
      } else {
        console.error(`Target ${target.id} unsuitable for send tab.`);
      }
    }
    if (fxaCommandsDevices.length) {
      console.log(
        `Sending a tab to ${fxaCommandsDevices
          .map(d => d.name)
          .join(", ")} using FxA commands.`
      );
      const report = await fxAccounts.commands.sendTab.send(
        fxaCommandsDevices,
        { url, title }
      );
      for (let { device, error } of report.failed) {
        console.error(
          `Failed to send a tab with FxA commands for ${device.name}.
                       Falling back on the Sync back-end`,
          error
        );
        if (!device.clientRecord) {
          console.error(
            `Could not find associated Sync device for ${device.name}`
          );
          continue;
        }
        oldSendTabClients.push(device.clientRecord);
      }
    }
    for (let client of oldSendTabClients) {
      try {
        console.log(`Sending a tab to ${client.name} using Sync.`);
        await Weave.Service.clientsEngine.sendURIToClientForDisplay(
          url,
          client.id,
          title
        );
      } catch (e) {
        console.error("Could not send tab to device.", e);
      }
    }
  },

  populateSendTabToDevicesMenu(
    devicesPopup,
    url,
    title,
    multiselected,
    createDeviceNodeFn
  ) {
    if (!createDeviceNodeFn) {
      createDeviceNodeFn = (targetId, name, targetType, lastModified) => {
        let eltName = name ? "menuitem" : "menuseparator";
        return document.createXULElement(eltName);
      };
    }

    // remove existing menu items
    for (let i = devicesPopup.children.length - 1; i >= 0; --i) {
      let child = devicesPopup.children[i];
      if (child.classList.contains("sync-menuitem")) {
        child.remove();
      }
    }

    if (gSync.sendTabConfiguredAndLoading) {
      // We can only be in this case in the page action menu.
      return;
    }

    const fragment = document.createDocumentFragment();

    const state = UIState.get();
    if (
      state.status == UIState.STATUS_SIGNED_IN &&
      this.sendTabTargets.length > 0
    ) {
      this._appendSendTabDeviceList(
        fragment,
        createDeviceNodeFn,
        url,
        title,
        multiselected
      );
    } else if (state.status == UIState.STATUS_SIGNED_IN) {
      this._appendSendTabSingleDevice(fragment, createDeviceNodeFn);
    } else if (
      state.status == UIState.STATUS_NOT_VERIFIED ||
      state.status == UIState.STATUS_LOGIN_FAILED
    ) {
      this._appendSendTabVerify(fragment, createDeviceNodeFn);
    } /* status is STATUS_NOT_CONFIGURED */ else {
      this._appendSendTabUnconfigured(fragment, createDeviceNodeFn);
    }

    devicesPopup.appendChild(fragment);
  },

  // TODO: once our transition from the old-send tab world is complete,
  // this list should be built using the FxA device list instead of the client
  // collection.
  _appendSendTabDeviceList(
    fragment,
    createDeviceNodeFn,
    url,
    title,
    multiselected
  ) {
    const targets = this.sendTabTargets;

    let tabsToSend = multiselected
      ? gBrowser.selectedTabs.map(t => {
          return {
            url: t.linkedBrowser.currentURI.spec,
            title: t.linkedBrowser.contentTitle,
          };
        })
      : [{ url, title }];

    const onSendAllCommand = event => {
      for (let t of tabsToSend) {
        this.sendTabToDevice(t.url, targets, t.title);
      }
    };
    const onTargetDeviceCommand = event => {
      const targetId = event.target.getAttribute("clientId");
      const target = targets.find(t => t.id == targetId);
      for (let t of tabsToSend) {
        this.sendTabToDevice(t.url, [target], t.title);
      }
    };

    function addTargetDevice(targetId, name, targetType, lastModified) {
      const targetDevice = createDeviceNodeFn(
        targetId,
        name,
        targetType,
        lastModified
      );
      targetDevice.addEventListener(
        "command",
        targetId ? onTargetDeviceCommand : onSendAllCommand,
        true
      );
      targetDevice.classList.add("sync-menuitem", "sendtab-target");
      targetDevice.setAttribute("clientId", targetId);
      targetDevice.setAttribute("clientType", targetType);
      targetDevice.setAttribute("label", name);
      fragment.appendChild(targetDevice);
    }

    for (let target of targets) {
      let type, lastModified;
      if (target.clientRecord) {
        type = Weave.Service.clientsEngine.getClientType(
          target.clientRecord.id
        );
        lastModified = new Date(target.clientRecord.serverLastModified * 1000);
      } else {
        type = target.type === "desktop" ? "desktop" : "phone"; // Normalizing the FxA types just in case.
        lastModified = null;
      }
      addTargetDevice(target.id, target.name, type, lastModified);
    }

    // "Send to All Devices" menu item
    if (targets.length > 1) {
      const separator = createDeviceNodeFn();
      separator.classList.add("sync-menuitem");
      fragment.appendChild(separator);
      const allDevicesLabel = this.fxaStrings.GetStringFromName(
        "sendToAllDevices.menuitem"
      );
      addTargetDevice("", allDevicesLabel, "");
    }
  },

  _appendSendTabSingleDevice(fragment, createDeviceNodeFn) {
    const noDevices = this.fxaStrings.GetStringFromName(
      "sendTabToDevice.singledevice.status"
    );
    const learnMore = this.fxaStrings.GetStringFromName(
      "sendTabToDevice.singledevice"
    );
    const connectDevice = this.fxaStrings.GetStringFromName(
      "sendTabToDevice.connectdevice"
    );
    const actions = [
      {
        label: connectDevice,
        command: () => this.openConnectAnotherDevice("sendtab"),
      },
      { label: learnMore, command: () => this.openSendToDevicePromo() },
    ];
    this._appendSendTabInfoItems(
      fragment,
      createDeviceNodeFn,
      noDevices,
      actions
    );
  },

  _appendSendTabVerify(fragment, createDeviceNodeFn) {
    const notVerified = this.fxaStrings.GetStringFromName(
      "sendTabToDevice.verify.status"
    );
    const verifyAccount = this.fxaStrings.GetStringFromName(
      "sendTabToDevice.verify"
    );
    const actions = [
      { label: verifyAccount, command: () => this.openPrefs("sendtab") },
    ];
    this._appendSendTabInfoItems(
      fragment,
      createDeviceNodeFn,
      notVerified,
      actions
    );
  },

  _appendSendTabUnconfigured(fragment, createDeviceNodeFn) {
    const notConnected = this.fxaStrings.GetStringFromName(
      "sendTabToDevice.unconfigured.status"
    );
    const learnMore = this.fxaStrings.GetStringFromName(
      "sendTabToDevice.unconfigured"
    );
    const actions = [
      { label: learnMore, command: () => this.openSendToDevicePromo() },
    ];
    this._appendSendTabInfoItems(
      fragment,
      createDeviceNodeFn,
      notConnected,
      actions
    );

    // Now add a 'sign in to sync' item above the 'learn more' item.
    const signInToSync = this.fxaStrings.GetStringFromName(
      "sendTabToDevice.signintosync"
    );
    let signInItem = createDeviceNodeFn(null, signInToSync, null);
    signInItem.classList.add("sync-menuitem");
    signInItem.setAttribute("label", signInToSync);
    // Show an icon if opened in the page action panel:
    if (signInItem.classList.contains("subviewbutton")) {
      signInItem.classList.add("subviewbutton-iconic", "signintosync");
    }
    signInItem.addEventListener("command", () => {
      this.openPrefs("sendtab");
    });
    fragment.insertBefore(signInItem, fragment.lastElementChild);
  },

  _appendSendTabInfoItems(fragment, createDeviceNodeFn, statusLabel, actions) {
    const status = createDeviceNodeFn(null, statusLabel, null);
    status.setAttribute("label", statusLabel);
    status.setAttribute("disabled", true);
    status.classList.add("sync-menuitem");
    fragment.appendChild(status);

    const separator = createDeviceNodeFn(null, null, null);
    separator.classList.add("sync-menuitem");
    fragment.appendChild(separator);

    for (let { label, command } of actions) {
      const actionItem = createDeviceNodeFn(null, label, null);
      actionItem.addEventListener("command", command, true);
      actionItem.classList.add("sync-menuitem");
      actionItem.setAttribute("label", label);
      fragment.appendChild(actionItem);
    }
  },

  isSendableURI(aURISpec) {
    if (!aURISpec) {
      return false;
    }
    // Disallow sending tabs with more than 65535 characters.
    if (aURISpec.length > 65535) {
      return false;
    }
    if (this.UNSENDABLE_URL_REGEXP) {
      return !this.UNSENDABLE_URL_REGEXP.test(aURISpec);
    }
    // The preference has been removed, or is an invalid regexp, so we treat it
    // as a valid URI. We've already logged an error when trying to construct
    // the regexp, and the more problematic case is the length, which we've
    // already addressed.
    return true;
  },

  // "Send Tab to Device" menu item
  updateTabContextMenu(aPopupMenu, aTargetTab) {
    // We may get here before initialisation. This situation
    // can lead to a empty label for 'Send To Device' Menu.
    this.init();

    if (!this.SYNC_ENABLED) {
      // These items are hidden in onSyncDisabled(). No need to do anything.
      return;
    }
    let hasASendableURI = false;
    for (let tab of aTargetTab.multiselected
      ? gBrowser.selectedTabs
      : [aTargetTab]) {
      if (this.isSendableURI(tab.linkedBrowser.currentURI.spec)) {
        hasASendableURI = true;
        break;
      }
    }
    const enabled = !this.sendTabConfiguredAndLoading && hasASendableURI;

    let sendTabsToDevice = document.getElementById("context_sendTabToDevice");
    sendTabsToDevice.disabled = !enabled;

    let tabCount = aTargetTab.multiselected
      ? gBrowser.multiSelectedTabsCount
      : 1;
    sendTabsToDevice.label = PluralForm.get(
      tabCount,
      gNavigatorBundle.getString("sendTabsToDevice.label")
    ).replace("#1", tabCount.toLocaleString());
    sendTabsToDevice.accessKey = gNavigatorBundle.getString(
      "sendTabsToDevice.accesskey"
    );
  },

  // "Send Page to Device" and "Send Link to Device" menu items
  updateContentContextMenu(contextMenu) {
    if (!this.SYNC_ENABLED) {
      // These items are hidden by default. No need to do anything.
      return;
    }
    // showSendLink and showSendPage are mutually exclusive
    const showSendLink =
      contextMenu.onSaveableLink || contextMenu.onPlainTextLink;
    const showSendPage =
      !showSendLink &&
      !(
        contextMenu.isContentSelected ||
        contextMenu.onImage ||
        contextMenu.onCanvas ||
        contextMenu.onVideo ||
        contextMenu.onAudio ||
        contextMenu.onLink ||
        contextMenu.onTextInput
      );

    // Avoids double separator on images with links.
    const hideSeparator =
      contextMenu.isContentSelected &&
      contextMenu.onLink &&
      contextMenu.onImage;
    [
      "context-sendpagetodevice",
      ...(hideSeparator ? [] : ["context-sep-sendpagetodevice"]),
    ].forEach(id => contextMenu.showItem(id, showSendPage));
    [
      "context-sendlinktodevice",
      ...(hideSeparator ? [] : ["context-sep-sendlinktodevice"]),
    ].forEach(id => contextMenu.showItem(id, showSendLink));

    if (!showSendLink && !showSendPage) {
      return;
    }

    const targetURI = showSendLink
      ? contextMenu.linkURL
      : contextMenu.browser.currentURI.spec;
    const enabled =
      !this.sendTabConfiguredAndLoading && this.isSendableURI(targetURI);
    contextMenu.setItemAttr(
      showSendPage ? "context-sendpagetodevice" : "context-sendlinktodevice",
      "disabled",
      !enabled || null
    );
  },

  // Functions called by observers
  onActivityStart() {
    clearTimeout(this._syncAnimationTimer);
    this._syncStartTime = Date.now();
    document.querySelectorAll(".syncNowBtn").forEach(el => {
      el.setAttribute("syncstatus", "active");
      el.setAttribute("disabled", "true");
      document.l10n.setAttributes(el, el.getAttribute("syncinglabel"));
    });
  },

  _onActivityStop() {
    if (!gBrowser) {
      return;
    }

    document.querySelectorAll(".syncNowBtn").forEach(el => {
      el.removeAttribute("syncstatus");
      el.removeAttribute("disabled");
      document.l10n.setAttributes(el, "fxa-toolbar-sync-now");
    });

    Services.obs.notifyObservers(null, "test:browser-sync:activity-stop");
  },

  onActivityStop() {
    let now = Date.now();
    let syncDuration = now - this._syncStartTime;

    if (syncDuration < MIN_STATUS_ANIMATION_DURATION) {
      let animationTime = MIN_STATUS_ANIMATION_DURATION - syncDuration;
      clearTimeout(this._syncAnimationTimer);
      this._syncAnimationTimer = setTimeout(
        () => this._onActivityStop(),
        animationTime
      );
    } else {
      this._onActivityStop();
    }
  },

  // Disconnect from sync, and optionally disconnect from the FxA account.
  // Returns true if the disconnection happened (ie, if the user didn't decline
  // when asked to confirm)
  async disconnect({ confirm = true, disconnectAccount = true } = {}) {
    if (confirm && !(await this._confirmDisconnect(disconnectAccount))) {
      return false;
    }
    await Weave.Service.promiseInitialized;
    await Weave.Service.startOver();
    if (disconnectAccount) {
      await fxAccounts.signOut();
    }
    return true;
  },

  /**
   * Prompts the user whether or not they want to proceed with
   * disconnecting from their Firefox Account or Sync.
   * @param {Boolean} disconnectAccount True if we are disconnecting both Sync and FxA.
   * @returns {Boolean} True if the user confirmed.
   */
  async _confirmDisconnect(disconnectAccount) {
    const l10nPrefix = `${
      disconnectAccount ? "fxa" : "sync"
    }-disconnect-dialog`;
    const [title, body, button] = await document.l10n.formatValues([
      { id: `${l10nPrefix}-title` },
      { id: `${l10nPrefix}-body` },
      { id: "sync-disconnect-dialog-button" },
    ]);
    // buttonPressed will be 0 for disconnect, 1 for cancel.
    const flags =
      Services.prompt.BUTTON_TITLE_IS_STRING * Services.prompt.BUTTON_POS_0 +
      Services.prompt.BUTTON_TITLE_CANCEL * Services.prompt.BUTTON_POS_1;
    const buttonPressed = Services.prompt.confirmEx(
      window,
      title,
      body,
      flags,
      button,
      null,
      null,
      null,
      {}
    );
    return buttonPressed == 0;
  },

  // doSync forces a sync - it *does not* return a promise as it is called
  // via the various UI components.
  doSync() {
    if (!UIState.isReady()) {
      return;
    }
    const state = UIState.get();
    if (state.status == UIState.STATUS_SIGNED_IN) {
      this.updateSyncStatus({ syncing: true });
      Services.tm.dispatchToMainThread(() => {
        // We are pretty confident that push helps us pick up all FxA commands,
        // but some users might have issues with push, so let's unblock them
        // by fetching the missed FxA commands on manual sync.
        fxAccounts.commands.pollDeviceCommands().catch(e => {
          console.error("Fetching missed remote commands failed.", e);
        });
        Weave.Service.sync();
      });
    }
  },

  doSyncFromFxaMenu(panel) {
    this.doSync();
    this.emitFxaToolbarTelemetry("sync_now", panel);
  },

  openPrefs(entryPoint = "syncbutton", origin = undefined) {
    window.openPreferences("paneSync", {
      origin,
      urlParams: { entrypoint: entryPoint },
    });
  },

  openPrefsFromFxaMenu(type, panel) {
    this.emitFxaToolbarTelemetry(type, panel);
    let entryPoint = "fxa_discoverability_native";
    if (this.isPanelInsideAppMenu(panel)) {
      entryPoint = "fxa_app_menu";
    }
    this.openPrefs(entryPoint);
  },

  openSyncedTabsPanel() {
    let placement = CustomizableUI.getPlacementOfWidget("sync-button");
    let area = placement && placement.area;
    let anchor =
      document.getElementById("sync-button") ||
      document.getElementById("PanelUI-menu-button");
    if (area == CustomizableUI.AREA_FIXED_OVERFLOW_PANEL) {
      // The button is in the overflow panel, so we need to show the panel,
      // then show our subview.
      let navbar = document.getElementById(CustomizableUI.AREA_NAVBAR);
      navbar.overflowable.show().then(() => {
        PanelUI.showSubView("PanelUI-remotetabs", anchor);
      }, Cu.reportError);
    } else {
      // It is placed somewhere else - just try and show it.
      PanelUI.showSubView("PanelUI-remotetabs", anchor);
    }
  },

  refreshSyncButtonsTooltip() {
    const state = UIState.get();
    this.updateSyncButtonsTooltip(state);
  },

  /* Update the tooltip for the sync icon in the main menu and in Synced Tabs.
     If Sync is configured, the tooltip is when the last sync occurred,
     otherwise the tooltip reflects the fact that Sync needs to be
     (re-)configured.
  */
  updateSyncButtonsTooltip(state) {
    const status = state.status;

    // This is a little messy as the Sync buttons are 1/2 Sync related and
    // 1/2 FxA related - so for some strings we use Sync strings, but for
    // others we reach into gSync for strings.
    let tooltiptext;
    if (status == UIState.STATUS_NOT_VERIFIED) {
      // "needs verification"
      tooltiptext = this.fxaStrings.formatStringFromName(
        "verifyDescription",
        [state.email]
      );
    } else if (status == UIState.STATUS_NOT_CONFIGURED) {
      // "needs setup".
      tooltiptext = this.syncStrings.GetStringFromName(
        "signInToSync.description"
      );
    } else if (status == UIState.STATUS_LOGIN_FAILED) {
      // "need to reconnect/re-enter your password"
      tooltiptext = this.fxaStrings.formatStringFromName(
        "reconnectDescription",
        [state.email]
      );
    } else {
      // Sync appears configured - format the "last synced at" time.
      tooltiptext = this.formatLastSyncDate(state.lastSync);
    }

    document.querySelectorAll(".syncNowBtn").forEach(el => {
      if (tooltiptext) {
        el.setAttribute("tooltiptext", tooltiptext);
      } else {
        el.removeAttribute("tooltiptext");
      }
    });
  },

  get relativeTimeFormat() {
    delete this.relativeTimeFormat;
    return (this.relativeTimeFormat = new Services.intl.RelativeTimeFormat(
      undefined,
      { style: "long" }
    ));
  },

  formatLastSyncDate(date) {
    if (!date) {
      // Date can be null before the first sync!
      return null;
    }
    const relativeDateStr = this.relativeTimeFormat.formatBestUnit(date);
    return this.syncStrings.formatStringFromName(
      "lastSync2.label",
      [relativeDateStr]
    );
  },

  onClientsSynced() {
    let element = document.getElementById("PanelUI-remotetabs-main");
    if (element) {
      if (Weave.Service.clientsEngine.stats.numClients > 1) {
        element.setAttribute("devices-status", "multi");
      } else {
        element.setAttribute("devices-status", "single");
      }
    }
  },

  onSyncDisabled() {
    const toHide = [...document.querySelectorAll(".sync-ui-item")];
    for (const item of toHide) {
      item.hidden = true;
    }
  },

  QueryInterface: ChromeUtils.generateQI([
    Ci.nsIObserver,
    Ci.nsISupportsWeakReference,
  ]),
};