/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
/* 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/. */

/* global window */

"use strict";

var Cu = Components.utils;
var { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
var Services = require("Services");
var promise = require("promise");
var defer = require("devtools/shared/defer");
var EventEmitter = require("devtools/shared/event-emitter");
const {executeSoon} = require("devtools/shared/DevToolsUtils");
var {KeyShortcuts} = require("devtools/client/shared/key-shortcuts");
var {Task} = require("devtools/shared/task");
const {initCssProperties} = require("devtools/shared/fronts/css-properties");
const nodeConstants = require("devtools/shared/dom-node-constants");
const Telemetry = require("devtools/client/shared/telemetry");

const Menu = require("devtools/client/framework/menu");
const MenuItem = require("devtools/client/framework/menu-item");

const {CommandUtils} = require("devtools/client/shared/developer-toolbar");
const {ComputedViewTool} = require("devtools/client/inspector/computed/computed");
const {FontInspector} = require("devtools/client/inspector/fonts/fonts");
const {HTMLBreadcrumbs} = require("devtools/client/inspector/breadcrumbs");
const {InspectorSearch} = require("devtools/client/inspector/inspector-search");
const MarkupView = require("devtools/client/inspector/markup/markup");
const {RuleViewTool} = require("devtools/client/inspector/rules/rules");
const {ToolSidebar} = require("devtools/client/inspector/toolsidebar");
const {ViewHelpers} = require("devtools/client/shared/widgets/view-helpers");
const clipboardHelper = require("devtools/shared/platform/clipboard");

const {LocalizationHelper, localizeMarkup} = require("devtools/shared/l10n");
const INSPECTOR_L10N =
      new LocalizationHelper("devtools/client/locales/inspector.properties");
const TOOLBOX_L10N = new LocalizationHelper("devtools/client/locales/toolbox.properties");

// Sidebar dimensions
const INITIAL_SIDEBAR_SIZE = 350;

// If the toolbox width is smaller than given amount of pixels,
// the sidebar automatically switches from 'landscape' to 'portrait' mode.
const PORTRAIT_MODE_WIDTH = 700;

/**
 * Represents an open instance of the Inspector for a tab.
 * The inspector controls the breadcrumbs, the markup view, and the sidebar
 * (computed view, rule view, font view and animation inspector).
 *
 * Events:
 * - ready
 *      Fired when the inspector panel is opened for the first time and ready to
 *      use
 * - new-root
 *      Fired after a new root (navigation to a new page) event was fired by
 *      the walker, and taken into account by the inspector (after the markup
 *      view has been reloaded)
 * - markuploaded
 *      Fired when the markup-view frame has loaded
 * - breadcrumbs-updated
 *      Fired when the breadcrumb widget updates to a new node
 * - boxmodel-view-updated
 *      Fired when the box model updates to a new node
 * - markupmutation
 *      Fired after markup mutations have been processed by the markup-view
 * - computed-view-refreshed
 *      Fired when the computed rules view updates to a new node
 * - computed-view-property-expanded
 *      Fired when a property is expanded in the computed rules view
 * - computed-view-property-collapsed
 *      Fired when a property is collapsed in the computed rules view
 * - computed-view-sourcelinks-updated
 *      Fired when the stylesheet source links have been updated (when switching
 *      to source-mapped files)
 * - computed-view-filtered
 *      Fired when the computed rules view is filtered
 * - rule-view-refreshed
 *      Fired when the rule view updates to a new node
 * - rule-view-sourcelinks-updated
 *      Fired when the stylesheet source links have been updated (when switching
 *      to source-mapped files)
 */
function Inspector(toolbox) {
  this._toolbox = toolbox;
  this._target = toolbox.target;
  this.panelDoc = window.document;
  this.panelWin = window;
  this.panelWin.inspector = this;

  this.telemetry = new Telemetry();

  this.nodeMenuTriggerInfo = null;

  this._handleRejectionIfNotDestroyed = this._handleRejectionIfNotDestroyed.bind(this);
  this._onBeforeNavigate = this._onBeforeNavigate.bind(this);
  this.onNewRoot = this.onNewRoot.bind(this);
  this._onContextMenu = this._onContextMenu.bind(this);
  this.onTextBoxContextMenu = this.onTextBoxContextMenu.bind(this);
  this._updateSearchResultsLabel = this._updateSearchResultsLabel.bind(this);
  this.onNewSelection = this.onNewSelection.bind(this);
  this.onDetached = this.onDetached.bind(this);
  this.onPaneToggleButtonClicked = this.onPaneToggleButtonClicked.bind(this);
  this._onMarkupFrameLoad = this._onMarkupFrameLoad.bind(this);
  this.onPanelWindowResize = this.onPanelWindowResize.bind(this);
  this.onSidebarShown = this.onSidebarShown.bind(this);
  this.onSidebarHidden = this.onSidebarHidden.bind(this);

  this._target.on("will-navigate", this._onBeforeNavigate);
  this._detectingActorFeatures = this._detectActorFeatures();

  EventEmitter.decorate(this);
}

Inspector.prototype = {
  /**
   * open is effectively an asynchronous constructor
   */
  init: Task.async(function* () {
    // Localize all the nodes containing a data-localization attribute.
    localizeMarkup(this.panelDoc);

    this._cssPropertiesLoaded = initCssProperties(this.toolbox);
    yield this._cssPropertiesLoaded;
    yield this.target.makeRemote();
    yield this._getPageStyle();

    // This may throw if the document is still loading and we are
    // refering to a dead about:blank document
    let defaultSelection = yield this._getDefaultNodeForSelection()
      .catch(this._handleRejectionIfNotDestroyed);

    return yield this._deferredOpen(defaultSelection);
  }),

  get toolbox() {
    return this._toolbox;
  },

  get inspector() {
    return this._toolbox.inspector;
  },

  get walker() {
    return this._toolbox.walker;
  },

  get selection() {
    return this._toolbox.selection;
  },

  get highlighter() {
    return this._toolbox.highlighter;
  },

  get isOuterHTMLEditable() {
    return this._target.client.traits.editOuterHTML;
  },

  get hasUrlToImageDataResolver() {
    return this._target.client.traits.urlToImageDataResolver;
  },

  get canGetUniqueSelector() {
    return this._target.client.traits.getUniqueSelector;
  },

  get canGetCssPath() {
    return this._target.client.traits.getCssPath;
  },

  get canGetUsedFontFaces() {
    return this._target.client.traits.getUsedFontFaces;
  },

  get canPasteInnerOrAdjacentHTML() {
    return this._target.client.traits.pasteHTML;
  },

  /**
   * Handle promise rejections for various asynchronous actions, and only log errors if
   * the inspector panel still exists.
   * This is useful to silence useless errors that happen when the inspector is closed
   * while still initializing (and making protocol requests).
   */
  _handleRejectionIfNotDestroyed: function (e) {
    if (!this._panelDestroyer) {
      console.error(e);
    }
  },

  /**
   * Figure out what features the backend supports
   */
  _detectActorFeatures: function () {
    this._supportsDuplicateNode = false;
    this._supportsScrollIntoView = false;
    this._supportsResolveRelativeURL = false;

    // Use getActorDescription first so that all actorHasMethod calls use
    // a cached response from the server.
    return this._target.getActorDescription("domwalker").then(desc => {
      return promise.all([
        this._target.actorHasMethod("domwalker", "duplicateNode").then(value => {
          this._supportsDuplicateNode = value;
        }).catch(e => console.error(e)),
        this._target.actorHasMethod("domnode", "scrollIntoView").then(value => {
          this._supportsScrollIntoView = value;
        }).catch(e => console.error(e)),
        this._target.actorHasMethod("inspector", "resolveRelativeURL").then(value => {
          this._supportsResolveRelativeURL = value;
        }).catch(e => console.error(e)),
      ]);
    });
  },

  _deferredOpen: function (defaultSelection) {
    let deferred = defer();

    this.breadcrumbs = new HTMLBreadcrumbs(this);

    this.walker.on("new-root", this.onNewRoot);

    this.selection.on("new-node-front", this.onNewSelection);
    this.selection.on("detached-front", this.onDetached);

    if (this.target.isLocalTab) {
      // Show a warning when the debugger is paused.
      // We show the warning only when the inspector
      // is selected.
      this.updateDebuggerPausedWarning = () => {
        let notificationBox = this._toolbox.getNotificationBox();
        let notification =
          notificationBox.getNotificationWithValue("inspector-script-paused");
        if (!notification && this._toolbox.currentToolId == "inspector" &&
            this._toolbox.threadClient.paused) {
          let message = INSPECTOR_L10N.getStr("debuggerPausedWarning.message");
          notificationBox.appendNotification(message,
            "inspector-script-paused", "", notificationBox.PRIORITY_WARNING_HIGH);
        }

        if (notification && this._toolbox.currentToolId != "inspector") {
          notificationBox.removeNotification(notification);
        }

        if (notification && !this._toolbox.threadClient.paused) {
          notificationBox.removeNotification(notification);
        }
      };
      this.target.on("thread-paused", this.updateDebuggerPausedWarning);
      this.target.on("thread-resumed", this.updateDebuggerPausedWarning);
      this._toolbox.on("select", this.updateDebuggerPausedWarning);
      this.updateDebuggerPausedWarning();
    }

    this._initMarkup();
    this.isReady = false;

    this.once("markuploaded", () => {
      this.isReady = true;

      // All the components are initialized. Let's select a node.
      if (defaultSelection) {
        this.selection.setNodeFront(defaultSelection, "inspector-open");
        this.markup.expandNode(this.selection.nodeFront);
      }

      // And setup the toolbar only now because it may depend on the document.
      this.setupToolbar();

      this.emit("ready");
      deferred.resolve(this);
    });

    this.setupSearchBox();
    this.setupSidebar();

    return deferred.promise;
  },

  _onBeforeNavigate: function () {
    this._defaultNode = null;
    this.selection.setNodeFront(null);
    this._destroyMarkup();
    this.isDirty = false;
    this._pendingSelection = null;
  },

  _getPageStyle: function () {
    return this.inspector.getPageStyle().then(pageStyle => {
      this.pageStyle = pageStyle;
    }, this._handleRejectionIfNotDestroyed);
  },

  /**
   * Return a promise that will resolve to the default node for selection.
   */
  _getDefaultNodeForSelection: function () {
    if (this._defaultNode) {
      return this._defaultNode;
    }
    let walker = this.walker;
    let rootNode = null;
    let pendingSelection = this._pendingSelection;

    // A helper to tell if the target has or is about to navigate.
    // this._pendingSelection changes on "will-navigate" and "new-root" events.
    let hasNavigated = () => pendingSelection !== this._pendingSelection;

    // If available, set either the previously selected node or the body
    // as default selected, else set documentElement
    return walker.getRootNode().then(node => {
      if (hasNavigated()) {
        return promise.reject("navigated; resolution of _defaultNode aborted");
      }

      rootNode = node;
      if (this.selectionCssSelector) {
        return walker.querySelector(rootNode, this.selectionCssSelector);
      }
      return null;
    }).then(front => {
      if (hasNavigated()) {
        return promise.reject("navigated; resolution of _defaultNode aborted");
      }

      if (front) {
        return front;
      }
      return walker.querySelector(rootNode, "body");
    }).then(front => {
      if (hasNavigated()) {
        return promise.reject("navigated; resolution of _defaultNode aborted");
      }

      if (front) {
        return front;
      }
      return this.walker.documentElement();
    }).then(node => {
      if (hasNavigated()) {
        return promise.reject("navigated; resolution of _defaultNode aborted");
      }
      this._defaultNode = node;
      return node;
    });
  },

  /**
   * Target getter.
   */
  get target() {
    return this._target;
  },

  /**
   * Target setter.
   */
  set target(value) {
    this._target = value;
  },

  /**
   * Indicate that a tool has modified the state of the page.  Used to
   * decide whether to show the "are you sure you want to navigate"
   * notification.
   */
  markDirty: function () {
    this.isDirty = true;
  },

  /**
   * Hooks the searchbar to show result and auto completion suggestions.
   */
  setupSearchBox: function () {
    this.searchBox = this.panelDoc.getElementById("inspector-searchbox");
    this.searchClearButton = this.panelDoc.getElementById("inspector-searchinput-clear");
    this.searchResultsLabel = this.panelDoc.getElementById("inspector-searchlabel");

    this.search = new InspectorSearch(this, this.searchBox, this.searchClearButton);
    this.search.on("search-cleared", this._updateSearchResultsLabel);
    this.search.on("search-result", this._updateSearchResultsLabel);

    let shortcuts = new KeyShortcuts({
      window: this.panelDoc.defaultView,
    });
    let key = INSPECTOR_L10N.getStr("inspector.searchHTML.key");
    shortcuts.on(key, (name, event) => {
      // Prevent overriding same shortcut from the computed/rule views
      if (event.target.closest("#sidebar-panel-ruleview") ||
          event.target.closest("#sidebar-panel-computedview")) {
        return;
      }
      event.preventDefault();
      this.searchBox.focus();
    });
  },

  get searchSuggestions() {
    return this.search.autocompleter;
  },

  _updateSearchResultsLabel: function (event, result) {
    let str = "";
    if (event !== "search-cleared") {
      if (result) {
        str = INSPECTOR_L10N.getFormatStr(
          "inspector.searchResultsCount2", result.resultsIndex + 1, result.resultsLength);
      } else {
        str = INSPECTOR_L10N.getStr("inspector.searchResultsNone");
      }
    }

    this.searchResultsLabel.textContent = str;
  },

  get React() {
    return this._toolbox.React;
  },

  get ReactDOM() {
    return this._toolbox.ReactDOM;
  },

  get ReactRedux() {
    return this._toolbox.ReactRedux;
  },

  get browserRequire() {
    return this._toolbox.browserRequire;
  },

  get InspectorTabPanel() {
    if (!this._InspectorTabPanel) {
      this._InspectorTabPanel =
        this.React.createFactory(this.browserRequire(
        "devtools/client/inspector/components/inspector-tab-panel"));
    }
    return this._InspectorTabPanel;
  },

  /**
   * Check if the inspector should use the landscape mode.
   *
   * @return {Boolean} true if the inspector should be in landscape mode.
   */
  useLandscapeMode: function () {
    let { clientWidth } = this.panelDoc.getElementById("inspector-splitter-box");
    return clientWidth > PORTRAIT_MODE_WIDTH;
  },

  /**
   * Build Splitter located between the main and side area of
   * the Inspector panel.
   */
  setupSplitter: function () {
    let SplitBox = this.React.createFactory(this.browserRequire(
      "devtools/client/shared/components/splitter/split-box"));

    let splitter = SplitBox({
      className: "inspector-sidebar-splitter",
      initialWidth: INITIAL_SIDEBAR_SIZE,
      initialHeight: INITIAL_SIDEBAR_SIZE,
      splitterSize: 1,
      endPanelControl: true,
      startPanel: this.InspectorTabPanel({
        id: "inspector-main-content"
      }),
      endPanel: this.InspectorTabPanel({
        id: "inspector-sidebar-container"
      }),
      vert: this.useLandscapeMode(),
    });

    this._splitter = this.ReactDOM.render(splitter,
      this.panelDoc.getElementById("inspector-splitter-box"));

    this.panelWin.addEventListener("resize", this.onPanelWindowResize, true);

    // Persist splitter state in preferences.
    this.sidebar.on("show", this.onSidebarShown);
    this.sidebar.on("hide", this.onSidebarHidden);
    this.sidebar.on("destroy", this.onSidebarHidden);
  },

  /**
   * Splitter clean up.
   */
  teardownSplitter: function () {
    this.panelWin.removeEventListener("resize", this.onPanelWindowResize, true);

    this.sidebar.off("show", this.onSidebarShown);
    this.sidebar.off("hide", this.onSidebarHidden);
    this.sidebar.off("destroy", this.onSidebarHidden);
  },

  /**
   * If Toolbox width is less than 600 px, the splitter changes its mode
   * to `horizontal` to support portrait view.
   */
  onPanelWindowResize: function () {
    this._splitter.setState({
      vert: this.useLandscapeMode(),
    });
  },

  onSidebarShown: function () {
    let width;
    let height;

    // Initialize splitter size from preferences.
    try {
      width = Services.prefs.getIntPref("devtools.toolsidebar-width.inspector");
      height = Services.prefs.getIntPref("devtools.toolsidebar-height.inspector");
    } catch (e) {
      // Set width and height of the splitter. Only one
      // value is really useful at a time depending on the current
      // orientation (vertical/horizontal).
      // Having both is supported by the splitter component.
      width = INITIAL_SIDEBAR_SIZE;
      height = INITIAL_SIDEBAR_SIZE;
    }

    this._splitter.setState({width, height});
  },

  onSidebarHidden: function () {
    // Store the current splitter size to preferences.
    let state = this._splitter.state;
    Services.prefs.setIntPref("devtools.toolsidebar-width.inspector", state.width);
    Services.prefs.setIntPref("devtools.toolsidebar-height.inspector", state.height);
  },

  /**
   * Build the sidebar.
   */
  setupSidebar: function () {
    let tabbox = this.panelDoc.querySelector("#inspector-sidebar");
    this.sidebar = new ToolSidebar(tabbox, this, "inspector", {
      showAllTabsMenu: true
    });

    let defaultTab = Services.prefs.getCharPref("devtools.inspector.activeSidebar");

    this._setDefaultSidebar = (event, toolId) => {
      Services.prefs.setCharPref("devtools.inspector.activeSidebar", toolId);
    };

    this.sidebar.on("select", this._setDefaultSidebar);

    if (!Services.prefs.getBoolPref("devtools.fontinspector.enabled") &&
       defaultTab == "fontinspector") {
      defaultTab = "ruleview";
    }

    // Append all side panels
    this.sidebar.addExistingTab(
      "ruleview",
      INSPECTOR_L10N.getStr("inspector.sidebar.ruleViewTitle"),
      defaultTab == "ruleview");

    this.sidebar.addExistingTab(
      "computedview",
      INSPECTOR_L10N.getStr("inspector.sidebar.computedViewTitle"),
      defaultTab == "computedview");

    this.ruleview = new RuleViewTool(this, this.panelWin);
    this.computedview = new ComputedViewTool(this, this.panelWin);

    if (Services.prefs.getBoolPref("devtools.layoutview.enabled")) {
      const {LayoutView} = this.browserRequire("devtools/client/inspector/layout/layout");
      this.layoutview = new LayoutView(this, this.panelWin);
    }

    if (this.target.form.animationsActor) {
      this.sidebar.addFrameTab(
        "animationinspector",
        INSPECTOR_L10N.getStr("inspector.sidebar.animationInspectorTitle"),
        "chrome://devtools/content/animationinspector/animation-inspector.xhtml",
        defaultTab == "animationinspector");
    }

    if (Services.prefs.getBoolPref("devtools.fontinspector.enabled") &&
        this.canGetUsedFontFaces) {
      this.sidebar.addExistingTab(
        "fontinspector",
        INSPECTOR_L10N.getStr("inspector.sidebar.fontInspectorTitle"),
        defaultTab == "fontinspector");

      this.fontInspector = new FontInspector(this, this.panelWin);
      this.sidebar.toggleTab(true, "fontinspector");
    }

    // Setup the splitter before the sidebar is displayed so,
    // we don't miss any events.
    this.setupSplitter();

    this.sidebar.show(defaultTab);
  },

  /**
   * Register a side-panel tab. This API can be used outside of
   * DevTools (e.g. from an extension) as well as by DevTools
   * code base.
   *
   * @param {string} tab uniq id
   * @param {string} title tab title
   * @param {React.Component} panel component. See `InspectorPanelTab` as an example.
   * @param {boolean} selected true if the panel should be selected
   */
  addSidebarTab: function (id, title, panel, selected) {
    this.sidebar.addTab(id, title, panel, selected);
  },

  setupToolbar: function () {
    this.teardownToolbar();

    // Setup the sidebar toggle button.
    let SidebarToggle = this.React.createFactory(this.browserRequire(
      "devtools/client/shared/components/sidebar-toggle"));

    let sidebarToggle = SidebarToggle({
      onClick: this.onPaneToggleButtonClicked,
      collapsed: false,
      expandPaneTitle: INSPECTOR_L10N.getStr("inspector.expandPane"),
      collapsePaneTitle: INSPECTOR_L10N.getStr("inspector.collapsePane"),
    });

    let parentBox = this.panelDoc.getElementById("inspector-sidebar-toggle-box");
    this._sidebarToggle = this.ReactDOM.render(sidebarToggle, parentBox);

    // Setup the add-node button.
    this.addNode = this.addNode.bind(this);
    this.addNodeButton = this.panelDoc.getElementById("inspector-element-add-button");
    this.addNodeButton.addEventListener("click", this.addNode);

    // Setup the eye-dropper icon if we're in an HTML document and we have actor support.
    if (this.selection.nodeFront && this.selection.nodeFront.isInHTMLDocument) {
      this.target.actorHasMethod("inspector", "pickColorFromPage").then(value => {
        if (!value) {
          return;
        }

        this.onEyeDropperDone = this.onEyeDropperDone.bind(this);
        this.onEyeDropperButtonClicked = this.onEyeDropperButtonClicked.bind(this);
        this.eyeDropperButton = this.panelDoc
                                    .getElementById("inspector-eyedropper-toggle");
        this.eyeDropperButton.disabled = false;
        this.eyeDropperButton.title = INSPECTOR_L10N.getStr("inspector.eyedropper.label");
        this.eyeDropperButton.addEventListener("click", this.onEyeDropperButtonClicked);
      }, e => console.error(e));
    } else {
      let eyeDropperButton = this.panelDoc.getElementById("inspector-eyedropper-toggle");
      eyeDropperButton.disabled = true;
      eyeDropperButton.title = INSPECTOR_L10N.getStr("eyedropper.disabled.title");
    }
  },

  teardownToolbar: function () {
    this._sidebarToggle = null;

    if (this.addNodeButton) {
      this.addNodeButton.removeEventListener("click", this.addNode);
      this.addNodeButton = null;
    }

    if (this.eyeDropperButton) {
      this.eyeDropperButton.removeEventListener("click", this.onEyeDropperButtonClicked);
      this.eyeDropperButton = null;
    }
  },

  /**
   * Reset the inspector on new root mutation.
   */
  onNewRoot: function () {
    this._defaultNode = null;
    this.selection.setNodeFront(null);
    this._destroyMarkup();
    this.isDirty = false;

    let onNodeSelected = defaultNode => {
      // Cancel this promise resolution as a new one had
      // been queued up.
      if (this._pendingSelection != onNodeSelected) {
        return;
      }
      this._pendingSelection = null;
      this.selection.setNodeFront(defaultNode, "navigateaway");

      this._initMarkup();
      this.once("markuploaded", () => {
        if (!this.markup) {
          return;
        }
        this.markup.expandNode(this.selection.nodeFront);
        this.emit("new-root");
      });

      // Setup the toolbar again, since its content may depend on the current document.
      this.setupToolbar();
    };
    this._pendingSelection = onNodeSelected;
    this._getDefaultNodeForSelection()
        .then(onNodeSelected, this._handleRejectionIfNotDestroyed);
  },

  _selectionCssSelector: null,

  /**
   * Set the currently selected node unique css selector.
   * Will store the current target url along with it to allow pre-selection at
   * reload
   */
  set selectionCssSelector(cssSelector = null) {
    if (this._panelDestroyer) {
      return;
    }

    this._selectionCssSelector = {
      selector: cssSelector,
      url: this._target.url
    };
  },

  /**
   * Get the current selection unique css selector if any, that is, if a node
   * is actually selected and that node has been selected while on the same url
   */
  get selectionCssSelector() {
    if (this._selectionCssSelector &&
        this._selectionCssSelector.url === this._target.url) {
      return this._selectionCssSelector.selector;
    }
    return null;
  },

  /**
   * Can a new HTML element be inserted into the currently selected element?
   * @return {Boolean}
   */
  canAddHTMLChild: function () {
    let selection = this.selection;

    // Don't allow to insert an element into these elements. This should only
    // contain elements where walker.insertAdjacentHTML has no effect.
    let invalidTagNames = ["html", "iframe"];

    return selection.isHTMLNode() &&
           selection.isElementNode() &&
           !selection.isPseudoElementNode() &&
           !selection.isAnonymousNode() &&
           invalidTagNames.indexOf(
            selection.nodeFront.nodeName.toLowerCase()) === -1;
  },

  /**
   * When a new node is selected.
   */
  onNewSelection: function (event, value, reason) {
    if (reason === "selection-destroy") {
      return;
    }

    // Wait for all the known tools to finish updating and then let the
    // client know.
    let selection = this.selection.nodeFront;

    // Update the state of the add button in the toolbar depending on the
    // current selection.
    let btn = this.panelDoc.querySelector("#inspector-element-add-button");
    if (this.canAddHTMLChild()) {
      btn.removeAttribute("disabled");
    } else {
      btn.setAttribute("disabled", "true");
    }

    // On any new selection made by the user, store the unique css selector
    // of the selected node so it can be restored after reload of the same page
    if (this.canGetUniqueSelector &&
        this.selection.isElementNode()) {
      selection.getUniqueSelector().then(selector => {
        this.selectionCssSelector = selector;
      }, this._handleRejectionIfNotDestroyed);
    }

    let selfUpdate = this.updating("inspector-panel");
    executeSoon(() => {
      try {
        selfUpdate(selection);
      } catch (ex) {
        console.error(ex);
      }
    });
  },

  /**
   * Delay the "inspector-updated" notification while a tool
   * is updating itself.  Returns a function that must be
   * invoked when the tool is done updating with the node
   * that the tool is viewing.
   */
  updating: function (name) {
    if (this._updateProgress && this._updateProgress.node != this.selection.nodeFront) {
      this.cancelUpdate();
    }

    if (!this._updateProgress) {
      // Start an update in progress.
      let self = this;
      this._updateProgress = {
        node: this.selection.nodeFront,
        outstanding: new Set(),
        checkDone: function () {
          if (this !== self._updateProgress) {
            return;
          }
          // Cancel update if there is no `selection` anymore.
          // It can happen if the inspector panel is already destroyed.
          if (!self.selection || (this.node !== self.selection.nodeFront)) {
            self.cancelUpdate();
            return;
          }
          if (this.outstanding.size !== 0) {
            return;
          }

          self._updateProgress = null;
          self.emit("inspector-updated", name);
        },
      };
    }

    let progress = this._updateProgress;
    let done = function () {
      progress.outstanding.delete(done);
      progress.checkDone();
    };
    progress.outstanding.add(done);
    return done;
  },

  /**
   * Cancel notification of inspector updates.
   */
  cancelUpdate: function () {
    this._updateProgress = null;
  },

  /**
   * When a node is deleted, select its parent node or the defaultNode if no
   * parent is found (may happen when deleting an iframe inside which the
   * node was selected).
   */
  onDetached: function (event, parentNode) {
    this.breadcrumbs.cutAfter(this.breadcrumbs.indexOf(parentNode));
    this.selection.setNodeFront(parentNode ? parentNode : this._defaultNode, "detached");
  },

  /**
   * Destroy the inspector.
   */
  destroy: function () {
    if (this._panelDestroyer) {
      return this._panelDestroyer;
    }

    if (this.walker) {
      this.walker.off("new-root", this.onNewRoot);
      this.pageStyle = null;
    }

    this.cancelUpdate();

    this.target.off("will-navigate", this._onBeforeNavigate);

    this.target.off("thread-paused", this.updateDebuggerPausedWarning);
    this.target.off("thread-resumed", this.updateDebuggerPausedWarning);
    this._toolbox.off("select", this.updateDebuggerPausedWarning);

    if (this.ruleview) {
      this.ruleview.destroy();
    }

    if (this.computedview) {
      this.computedview.destroy();
    }

    if (this.layoutview) {
      this.layoutview.destroy();
    }

    if (this.fontInspector) {
      this.fontInspector.destroy();
    }

    let cssPropertiesDestroyer = this._cssPropertiesLoaded.then(({front}) => {
      if (front) {
        front.destroy();
      }
    });

    this.sidebar.off("select", this._setDefaultSidebar);
    let sidebarDestroyer = this.sidebar.destroy();

    this.teardownSplitter();

    this.sidebar = null;

    this.teardownToolbar();
    this.breadcrumbs.destroy();
    this.selection.off("new-node-front", this.onNewSelection);
    this.selection.off("detached-front", this.onDetached);
    let markupDestroyer = this._destroyMarkup();
    this.panelWin.inspector = null;
    this.target = null;
    this.panelDoc = null;
    this.panelWin = null;
    this.breadcrumbs = null;
    this._toolbox = null;
    this.search.destroy();
    this.search = null;
    this.searchBox = null;

    this._panelDestroyer = promise.all([
      sidebarDestroyer,
      markupDestroyer,
      cssPropertiesDestroyer
    ]);

    return this._panelDestroyer;
  },

  /**
   * Returns the clipboard content if it is appropriate for pasting
   * into the current node's outer HTML, otherwise returns null.
   */
  _getClipboardContentForPaste: function () {
    let flavors = clipboardHelper.getCurrentFlavors();
    if (flavors.indexOf("text") != -1 ||
        (flavors.indexOf("html") != -1 && flavors.indexOf("image") == -1)) {
      let content = clipboardHelper.getData();
      if (content && content.trim().length > 0) {
        return content;
      }
    }
    return null;
  },

  _onContextMenu: function (e) {
    e.preventDefault();
    this._openMenu({
      screenX: e.screenX,
      screenY: e.screenY,
      target: e.target,
    });
  },

  /**
   * This is meant to be called by all the search, filter, inplace text boxes in the
   * inspector, and just calls through to the toolbox openTextBoxContextMenu helper.
   * @param {DOMEvent} e
   */
  onTextBoxContextMenu: function (e) {
    e.stopPropagation();
    e.preventDefault();
    this.toolbox.openTextBoxContextMenu(e.screenX, e.screenY);
  },

  _openMenu: function ({ target, screenX = 0, screenY = 0 } = { }) {
    let markupContainer = this.markup.getContainer(this.selection.nodeFront);

    this.contextMenuTarget = target;
    this.nodeMenuTriggerInfo = markupContainer &&
      markupContainer.editor.getInfoAtNode(target);

    let isSelectionElement = this.selection.isElementNode() &&
                             !this.selection.isPseudoElementNode();
    let isEditableElement = isSelectionElement &&
                            !this.selection.isAnonymousNode();
    let isDuplicatableElement = isSelectionElement &&
                                !this.selection.isAnonymousNode() &&
                                !this.selection.isRoot();
    let isScreenshotable = isSelectionElement &&
                           this.canGetUniqueSelector &&
                           this.selection.nodeFront.isTreeDisplayed;

    let menu = new Menu();
    menu.append(new MenuItem({
      id: "node-menu-edithtml",
      label: INSPECTOR_L10N.getStr("inspectorHTMLEdit.label"),
      accesskey: INSPECTOR_L10N.getStr("inspectorHTMLEdit.accesskey"),
      disabled: !isEditableElement || !this.isOuterHTMLEditable,
      click: () => this.editHTML(),
    }));
    menu.append(new MenuItem({
      id: "node-menu-add",
      label: INSPECTOR_L10N.getStr("inspectorAddNode.label"),
      accesskey: INSPECTOR_L10N.getStr("inspectorAddNode.accesskey"),
      disabled: !this.canAddHTMLChild(),
      click: () => this.addNode(),
    }));
    menu.append(new MenuItem({
      id: "node-menu-duplicatenode",
      label: INSPECTOR_L10N.getStr("inspectorDuplicateNode.label"),
      hidden: !this._supportsDuplicateNode,
      disabled: !isDuplicatableElement,
      click: () => this.duplicateNode(),
    }));
    menu.append(new MenuItem({
      id: "node-menu-delete",
      label: INSPECTOR_L10N.getStr("inspectorHTMLDelete.label"),
      accesskey: INSPECTOR_L10N.getStr("inspectorHTMLDelete.accesskey"),
      disabled: !isEditableElement,
      click: () => this.deleteNode(),
    }));

    menu.append(new MenuItem({
      label: INSPECTOR_L10N.getStr("inspectorAttributesSubmenu.label"),
      accesskey:
        INSPECTOR_L10N.getStr("inspectorAttributesSubmenu.accesskey"),
      submenu: this._getAttributesSubmenu(isEditableElement),
    }));

    menu.append(new MenuItem({
      type: "separator",
    }));

    // Set the pseudo classes
    for (let name of ["hover", "active", "focus"]) {
      let menuitem = new MenuItem({
        id: "node-menu-pseudo-" + name,
        label: name,
        type: "checkbox",
        click: this.togglePseudoClass.bind(this, ":" + name),
      });

      if (isSelectionElement) {
        let checked = this.selection.nodeFront.hasPseudoClassLock(":" + name);
        menuitem.checked = checked;
      } else {
        menuitem.disabled = true;
      }

      menu.append(menuitem);
    }

    menu.append(new MenuItem({
      type: "separator",
    }));

    let copySubmenu = new Menu();
    copySubmenu.append(new MenuItem({
      id: "node-menu-copyinner",
      label: INSPECTOR_L10N.getStr("inspectorCopyInnerHTML.label"),
      accesskey: INSPECTOR_L10N.getStr("inspectorCopyInnerHTML.accesskey"),
      disabled: !isSelectionElement,
      click: () => this.copyInnerHTML(),
    }));
    copySubmenu.append(new MenuItem({
      id: "node-menu-copyouter",
      label: INSPECTOR_L10N.getStr("inspectorCopyOuterHTML.label"),
      accesskey: INSPECTOR_L10N.getStr("inspectorCopyOuterHTML.accesskey"),
      disabled: !isSelectionElement,
      click: () => this.copyOuterHTML(),
    }));
    copySubmenu.append(new MenuItem({
      id: "node-menu-copyuniqueselector",
      label: INSPECTOR_L10N.getStr("inspectorCopyCSSSelector.label"),
      accesskey:
        INSPECTOR_L10N.getStr("inspectorCopyCSSSelector.accesskey"),
      disabled: !isSelectionElement,
      hidden: !this.canGetUniqueSelector,
      click: () => this.copyUniqueSelector(),
    }));
    copySubmenu.append(new MenuItem({
      id: "node-menu-copycsspath",
      label: INSPECTOR_L10N.getStr("inspectorCopyCSSPath.label"),
      accesskey:
        INSPECTOR_L10N.getStr("inspectorCopyCSSPath.accesskey"),
      disabled: !isSelectionElement,
      hidden: !this.canGetCssPath,
      click: () => this.copyCssPath(),
    }));
    copySubmenu.append(new MenuItem({
      id: "node-menu-copyimagedatauri",
      label: INSPECTOR_L10N.getStr("inspectorImageDataUri.label"),
      disabled: !isSelectionElement || !markupContainer ||
                !markupContainer.isPreviewable(),
      click: () => this.copyImageDataUri(),
    }));

    menu.append(new MenuItem({
      label: INSPECTOR_L10N.getStr("inspectorCopyHTMLSubmenu.label"),
      submenu: copySubmenu,
    }));

    menu.append(new MenuItem({
      label: INSPECTOR_L10N.getStr("inspectorPasteHTMLSubmenu.label"),
      submenu: this._getPasteSubmenu(isEditableElement),
    }));

    menu.append(new MenuItem({
      type: "separator",
    }));

    let isNodeWithChildren = this.selection.isNode() &&
                             markupContainer.hasChildren;
    menu.append(new MenuItem({
      id: "node-menu-expand",
      label: INSPECTOR_L10N.getStr("inspectorExpandNode.label"),
      disabled: !isNodeWithChildren,
      click: () => this.expandNode(),
    }));
    menu.append(new MenuItem({
      id: "node-menu-collapse",
      label: INSPECTOR_L10N.getStr("inspectorCollapseNode.label"),
      disabled: !isNodeWithChildren || !markupContainer.expanded,
      click: () => this.collapseNode(),
    }));

    menu.append(new MenuItem({
      type: "separator",
    }));

    menu.append(new MenuItem({
      id: "node-menu-scrollnodeintoview",
      label: INSPECTOR_L10N.getStr("inspectorScrollNodeIntoView.label"),
      accesskey:
        INSPECTOR_L10N.getStr("inspectorScrollNodeIntoView.accesskey"),
      hidden: !this._supportsScrollIntoView,
      disabled: !isSelectionElement,
      click: () => this.scrollNodeIntoView(),
    }));
    menu.append(new MenuItem({
      id: "node-menu-screenshotnode",
      label: INSPECTOR_L10N.getStr("inspectorScreenshotNode.label"),
      disabled: !isScreenshotable,
      click: () => this.screenshotNode(),
    }));
    menu.append(new MenuItem({
      id: "node-menu-useinconsole",
      label: INSPECTOR_L10N.getStr("inspectorUseInConsole.label"),
      click: () => this.useInConsole(),
    }));
    menu.append(new MenuItem({
      id: "node-menu-showdomproperties",
      label: INSPECTOR_L10N.getStr("inspectorShowDOMProperties.label"),
      click: () => this.showDOMProperties(),
    }));

    let nodeLinkMenuItems = this._getNodeLinkMenuItems();
    if (nodeLinkMenuItems.filter(item => item.visible).length > 0) {
      menu.append(new MenuItem({
        id: "node-menu-link-separator",
        type: "separator",
      }));
    }

    for (let menuitem of nodeLinkMenuItems) {
      menu.append(menuitem);
    }

    menu.popup(screenX, screenY, this._toolbox);
    return menu;
  },

  _getPasteSubmenu: function (isEditableElement) {
    let isPasteable = isEditableElement && this._getClipboardContentForPaste();
    let disableAdjacentPaste = !isPasteable ||
          !this.canPasteInnerOrAdjacentHTML || this.selection.isRoot() ||
          this.selection.isBodyNode() || this.selection.isHeadNode();
    let disableFirstLastPaste = !isPasteable ||
          !this.canPasteInnerOrAdjacentHTML || (this.selection.isHTMLNode() &&
          this.selection.isRoot());

    let pasteSubmenu = new Menu();
    pasteSubmenu.append(new MenuItem({
      id: "node-menu-pasteinnerhtml",
      label: INSPECTOR_L10N.getStr("inspectorPasteInnerHTML.label"),
      accesskey: INSPECTOR_L10N.getStr("inspectorPasteInnerHTML.accesskey"),
      disabled: !isPasteable || !this.canPasteInnerOrAdjacentHTML,
      click: () => this.pasteInnerHTML(),
    }));
    pasteSubmenu.append(new MenuItem({
      id: "node-menu-pasteouterhtml",
      label: INSPECTOR_L10N.getStr("inspectorPasteOuterHTML.label"),
      accesskey: INSPECTOR_L10N.getStr("inspectorPasteOuterHTML.accesskey"),
      disabled: !isPasteable || !this.isOuterHTMLEditable,
      click: () => this.pasteOuterHTML(),
    }));
    pasteSubmenu.append(new MenuItem({
      id: "node-menu-pastebefore",
      label: INSPECTOR_L10N.getStr("inspectorHTMLPasteBefore.label"),
      accesskey:
        INSPECTOR_L10N.getStr("inspectorHTMLPasteBefore.accesskey"),
      disabled: disableAdjacentPaste,
      click: () => this.pasteAdjacentHTML("beforeBegin"),
    }));
    pasteSubmenu.append(new MenuItem({
      id: "node-menu-pasteafter",
      label: INSPECTOR_L10N.getStr("inspectorHTMLPasteAfter.label"),
      accesskey:
        INSPECTOR_L10N.getStr("inspectorHTMLPasteAfter.accesskey"),
      disabled: disableAdjacentPaste,
      click: () => this.pasteAdjacentHTML("afterEnd"),
    }));
    pasteSubmenu.append(new MenuItem({
      id: "node-menu-pastefirstchild",
      label: INSPECTOR_L10N.getStr("inspectorHTMLPasteFirstChild.label"),
      accesskey:
        INSPECTOR_L10N.getStr("inspectorHTMLPasteFirstChild.accesskey"),
      disabled: disableFirstLastPaste,
      click: () => this.pasteAdjacentHTML("afterBegin"),
    }));
    pasteSubmenu.append(new MenuItem({
      id: "node-menu-pastelastchild",
      label: INSPECTOR_L10N.getStr("inspectorHTMLPasteLastChild.label"),
      accesskey:
        INSPECTOR_L10N.getStr("inspectorHTMLPasteLastChild.accesskey"),
      disabled: disableFirstLastPaste,
      click: () => this.pasteAdjacentHTML("beforeEnd"),
    }));

    return pasteSubmenu;
  },

  _getAttributesSubmenu: function (isEditableElement) {
    let attributesSubmenu = new Menu();
    let nodeInfo = this.nodeMenuTriggerInfo;
    let isAttributeClicked = isEditableElement && nodeInfo &&
                              nodeInfo.type === "attribute";

    attributesSubmenu.append(new MenuItem({
      id: "node-menu-add-attribute",
      label: INSPECTOR_L10N.getStr("inspectorAddAttribute.label"),
      accesskey: INSPECTOR_L10N.getStr("inspectorAddAttribute.accesskey"),
      disabled: !isEditableElement,
      click: () => this.onAddAttribute(),
    }));
    attributesSubmenu.append(new MenuItem({
      id: "node-menu-edit-attribute",
      label: INSPECTOR_L10N.getFormatStr("inspectorEditAttribute.label",
                                        isAttributeClicked ? `"${nodeInfo.name}"` : ""),
      accesskey: INSPECTOR_L10N.getStr("inspectorEditAttribute.accesskey"),
      disabled: !isAttributeClicked,
      click: () => this.onEditAttribute(),
    }));

    attributesSubmenu.append(new MenuItem({
      id: "node-menu-remove-attribute",
      label: INSPECTOR_L10N.getFormatStr("inspectorRemoveAttribute.label",
                                        isAttributeClicked ? `"${nodeInfo.name}"` : ""),
      accesskey:
        INSPECTOR_L10N.getStr("inspectorRemoveAttribute.accesskey"),
      disabled: !isAttributeClicked,
      click: () => this.onRemoveAttribute(),
    }));

    return attributesSubmenu;
  },

  /**
   * Link menu items can be shown or hidden depending on the context and
   * selected node, and their labels can vary.
   *
   * @return {Array} list of visible menu items related to links.
   */
  _getNodeLinkMenuItems: function () {
    let linkFollow = new MenuItem({
      id: "node-menu-link-follow",
      visible: false,
      click: () => this.onFollowLink(),
    });
    let linkCopy = new MenuItem({
      id: "node-menu-link-copy",
      visible: false,
      click: () => this.onCopyLink(),
    });

    // Get information about the right-clicked node.
    let popupNode = this.contextMenuTarget;
    if (!popupNode || !popupNode.classList.contains("link")) {
      return [linkFollow, linkCopy];
    }

    let type = popupNode.dataset.type;
    if (this._supportsResolveRelativeURL &&
        (type === "uri" || type === "cssresource" || type === "jsresource")) {
      // Links can't be opened in new tabs in the browser toolbox.
      if (type === "uri" && !this.target.chrome) {
        linkFollow.visible = true;
        linkFollow.label = INSPECTOR_L10N.getStr(
          "inspector.menu.openUrlInNewTab.label");
      } else if (type === "cssresource") {
        linkFollow.visible = true;
        linkFollow.label = TOOLBOX_L10N.getStr(
          "toolbox.viewCssSourceInStyleEditor.label");
      } else if (type === "jsresource") {
        linkFollow.visible = true;
        linkFollow.label = TOOLBOX_L10N.getStr(
          "toolbox.viewJsSourceInDebugger.label");
      }

      linkCopy.visible = true;
      linkCopy.label = INSPECTOR_L10N.getStr(
        "inspector.menu.copyUrlToClipboard.label");
    } else if (type === "idref") {
      linkFollow.visible = true;
      linkFollow.label = INSPECTOR_L10N.getFormatStr(
        "inspector.menu.selectElement.label", popupNode.dataset.link);
    }

    return [linkFollow, linkCopy];
  },

  _initMarkup: function () {
    let doc = this.panelDoc;

    this._markupBox = doc.getElementById("markup-box");

    // create tool iframe
    this._markupFrame = doc.createElement("iframe");
    this._markupFrame.setAttribute("flex", "1");
    this._markupFrame.setAttribute("tooltip", "aHTMLTooltip");
    this._markupFrame.addEventListener("contextmenu", this._onContextMenu);

    // This is needed to enable tooltips inside the iframe document.
    this._markupFrame.addEventListener("load", this._onMarkupFrameLoad, true);

    this._markupBox.setAttribute("collapsed", true);
    this._markupBox.appendChild(this._markupFrame);
    this._markupFrame.setAttribute("src", "chrome://devtools/content/inspector/markup/markup.xhtml");
    this._markupFrame.setAttribute("aria-label",
      INSPECTOR_L10N.getStr("inspector.panelLabel.markupView"));
  },

  _onMarkupFrameLoad: function () {
    this._markupFrame.removeEventListener("load", this._onMarkupFrameLoad, true);

    this._markupFrame.contentWindow.focus();

    this._markupBox.removeAttribute("collapsed");

    this.markup = new MarkupView(this, this._markupFrame, this._toolbox.win);

    this.emit("markuploaded");
  },

  _destroyMarkup: function () {
    let destroyPromise;

    if (this._markupFrame) {
      this._markupFrame.removeEventListener("load", this._onMarkupFrameLoad, true);
      this._markupFrame.removeEventListener("contextmenu", this._onContextMenu);
    }

    if (this.markup) {
      destroyPromise = this.markup.destroy();
      this.markup = null;
    } else {
      destroyPromise = promise.resolve();
    }

    if (this._markupFrame) {
      this._markupFrame.parentNode.removeChild(this._markupFrame);
      this._markupFrame = null;
    }

    this._markupBox = null;

    return destroyPromise;
  },

  /**
   * When the pane toggle button is clicked or pressed, toggle the pane, change the button
   * state and tooltip.
   */
  onPaneToggleButtonClicked: function (e) {
    let sidePaneContainer = this.panelDoc.querySelector(
      "#inspector-splitter-box .controlled");
    let isVisible = !this._sidebarToggle.state.collapsed;

    // Make sure the sidebar has width and height attributes before collapsing
    // because ViewHelpers needs it.
    if (isVisible) {
      let rect = sidePaneContainer.getBoundingClientRect();
      if (!sidePaneContainer.hasAttribute("width")) {
        sidePaneContainer.setAttribute("width", rect.width);
      }
      // always refresh the height attribute before collapsing, it could have
      // been modified by resizing the container.
      sidePaneContainer.setAttribute("height", rect.height);
    }

    let onAnimationDone = () => {
      if (isVisible) {
        this._sidebarToggle.setState({collapsed: true});
      } else {
        this._sidebarToggle.setState({collapsed: false});
      }
    };

    ViewHelpers.togglePane({
      visible: !isVisible,
      animated: true,
      delayed: true,
      callback: onAnimationDone
    }, sidePaneContainer);
  },

  onEyeDropperButtonClicked: function () {
    this.eyeDropperButton.hasAttribute("checked")
      ? this.hideEyeDropper()
      : this.showEyeDropper();
  },

  startEyeDropperListeners: function () {
    this.inspector.once("color-pick-canceled", this.onEyeDropperDone);
    this.inspector.once("color-picked", this.onEyeDropperDone);
    this.walker.once("new-root", this.onEyeDropperDone);
  },

  stopEyeDropperListeners: function () {
    this.inspector.off("color-pick-canceled", this.onEyeDropperDone);
    this.inspector.off("color-picked", this.onEyeDropperDone);
    this.walker.off("new-root", this.onEyeDropperDone);
  },

  onEyeDropperDone: function () {
    this.eyeDropperButton.removeAttribute("checked");
    this.stopEyeDropperListeners();
  },

  /**
   * Show the eyedropper on the page.
   * @return {Promise} resolves when the eyedropper is visible.
   */
  showEyeDropper: function () {
    // The eyedropper button doesn't exist, most probably because the actor doesn't
    // support the pickColorFromPage, or because the page isn't HTML.
    if (!this.eyeDropperButton) {
      return null;
    }

    this.telemetry.toolOpened("toolbareyedropper");
    this.eyeDropperButton.setAttribute("checked", "true");
    this.startEyeDropperListeners();
    return this.inspector.pickColorFromPage(this.toolbox, {copyOnSelect: true})
                         .catch(e => console.error(e));
  },

  /**
   * Hide the eyedropper.
   * @return {Promise} resolves when the eyedropper is hidden.
   */
  hideEyeDropper: function () {
    // The eyedropper button doesn't exist, most probably because the actor doesn't
    // support the pickColorFromPage, or because the page isn't HTML.
    if (!this.eyeDropperButton) {
      return null;
    }

    this.eyeDropperButton.removeAttribute("checked");
    this.stopEyeDropperListeners();
    return this.inspector.cancelPickColorFromPage()
                         .catch(e => console.error(e));
  },

  /**
   * Create a new node as the last child of the current selection, expand the
   * parent and select the new node.
   */
  addNode: Task.async(function* () {
    if (!this.canAddHTMLChild()) {
      return;
    }

    let html = "<div></div>";

    // Insert the html and expect a childList markup mutation.
    let onMutations = this.once("markupmutation");
    let {nodes} = yield this.walker.insertAdjacentHTML(this.selection.nodeFront,
                                                       "beforeEnd", html);
    yield onMutations;

    // Select the new node (this will auto-expand its parent).
    this.selection.setNodeFront(nodes[0], "node-inserted");
  }),

  /**
   * Toggle a pseudo class.
   */
  togglePseudoClass: function (pseudo) {
    if (this.selection.isElementNode()) {
      let node = this.selection.nodeFront;
      if (node.hasPseudoClassLock(pseudo)) {
        return this.walker.removePseudoClassLock(node, pseudo, {parents: true});
      }

      let hierarchical = pseudo == ":hover" || pseudo == ":active";
      return this.walker.addPseudoClassLock(node, pseudo, {parents: hierarchical});
    }
    return promise.resolve();
  },

  /**
   * Show DOM properties
   */
  showDOMProperties: function () {
    this._toolbox.openSplitConsole().then(() => {
      let panel = this._toolbox.getPanel("webconsole");
      let jsterm = panel.hud.jsterm;

      jsterm.execute("inspect($0)");
      jsterm.focus();
    });
  },

  /**
   * Use in Console.
   *
   * Takes the currently selected node in the inspector and assigns it to a
   * temp variable on the content window.  Also opens the split console and
   * autofills it with the temp variable.
   */
  useInConsole: function () {
    this._toolbox.openSplitConsole().then(() => {
      let panel = this._toolbox.getPanel("webconsole");
      let jsterm = panel.hud.jsterm;

      let evalString = `{ let i = 0;
        while (window.hasOwnProperty("temp" + i) && i < 1000) {
          i++;
        }
        window["temp" + i] = $0;
        "temp" + i;
      }`;

      let options = {
        selectedNodeActor: this.selection.nodeFront.actorID,
      };
      jsterm.requestEvaluation(evalString, options).then((res) => {
        jsterm.setInputValue(res.result);
        this.emit("console-var-ready");
      });
    });
  },

  /**
   * Edit the outerHTML of the selected Node.
   */
  editHTML: function () {
    if (!this.selection.isNode()) {
      return;
    }
    if (this.markup) {
      this.markup.beginEditingOuterHTML(this.selection.nodeFront);
    }
  },

  /**
   * Paste the contents of the clipboard into the selected Node's outer HTML.
   */
  pasteOuterHTML: function () {
    let content = this._getClipboardContentForPaste();
    if (!content) {
      return promise.reject("No clipboard content for paste");
    }

    let node = this.selection.nodeFront;
    return this.markup.getNodeOuterHTML(node).then(oldContent => {
      this.markup.updateNodeOuterHTML(node, content, oldContent);
    });
  },

  /**
   * Paste the contents of the clipboard into the selected Node's inner HTML.
   */
  pasteInnerHTML: function () {
    let content = this._getClipboardContentForPaste();
    if (!content) {
      return promise.reject("No clipboard content for paste");
    }

    let node = this.selection.nodeFront;
    return this.markup.getNodeInnerHTML(node).then(oldContent => {
      this.markup.updateNodeInnerHTML(node, content, oldContent);
    });
  },

  /**
   * Paste the contents of the clipboard as adjacent HTML to the selected Node.
   * @param position
   *        The position as specified for Element.insertAdjacentHTML
   *        (i.e. "beforeBegin", "afterBegin", "beforeEnd", "afterEnd").
   */
  pasteAdjacentHTML: function (position) {
    let content = this._getClipboardContentForPaste();
    if (!content) {
      return promise.reject("No clipboard content for paste");
    }

    let node = this.selection.nodeFront;
    return this.markup.insertAdjacentHTMLToNode(node, position, content);
  },

  /**
   * Copy the innerHTML of the selected Node to the clipboard.
   */
  copyInnerHTML: function () {
    if (!this.selection.isNode()) {
      return;
    }
    this._copyLongString(this.walker.innerHTML(this.selection.nodeFront));
  },

  /**
   * Copy the outerHTML of the selected Node to the clipboard.
   */
  copyOuterHTML: function () {
    if (!this.selection.isNode()) {
      return;
    }
    let node = this.selection.nodeFront;

    switch (node.nodeType) {
      case nodeConstants.ELEMENT_NODE :
        this._copyLongString(this.walker.outerHTML(node));
        break;
      case nodeConstants.COMMENT_NODE :
        this._getLongString(node.getNodeValue()).then(comment => {
          clipboardHelper.copyString("<!--" + comment + "-->");
        });
        break;
      case nodeConstants.DOCUMENT_TYPE_NODE :
        clipboardHelper.copyString(node.doctypeString);
        break;
    }
  },

  /**
   * Copy the data-uri for the currently selected image in the clipboard.
   */
  copyImageDataUri: function () {
    let container = this.markup.getContainer(this.selection.nodeFront);
    if (container && container.isPreviewable()) {
      container.copyImageDataUri();
    }
  },

  /**
   * Copy the content of a longString (via a promise resolving a
   * LongStringActor) to the clipboard
   * @param  {Promise} longStringActorPromise
   *         promise expected to resolve a LongStringActor instance
   * @return {Promise} promise resolving (with no argument) when the
   *         string is sent to the clipboard
   */
  _copyLongString: function (longStringActorPromise) {
    return this._getLongString(longStringActorPromise).then(string => {
      clipboardHelper.copyString(string);
    }).catch(e => console.error(e));
  },

  /**
   * Retrieve the content of a longString (via a promise resolving a LongStringActor)
   * @param  {Promise} longStringActorPromise
   *         promise expected to resolve a LongStringActor instance
   * @return {Promise} promise resolving with the retrieved string as argument
   */
  _getLongString: function (longStringActorPromise) {
    return longStringActorPromise.then(longStringActor => {
      return longStringActor.string().then(string => {
        longStringActor.release().catch(e => console.error(e));
        return string;
      });
    }).catch(e => console.error(e));
  },

  /**
   * Copy a unique selector of the selected Node to the clipboard.
   */
  copyUniqueSelector: function () {
    if (!this.selection.isNode()) {
      return;
    }

    this.telemetry.toolOpened("copyuniquecssselector");
    this.selection.nodeFront.getUniqueSelector().then(selector => {
      clipboardHelper.copyString(selector);
    }).catch(e => console.error);
  },

  /**
   * Copy the full CSS Path of the selected Node to the clipboard.
   */
  copyCssPath: function () {
    if (!this.selection.isNode()) {
      return;
    }

    this.telemetry.toolOpened("copyfullcssselector");
    this.selection.nodeFront.getCssPath().then(path => {
      clipboardHelper.copyString(path);
    }).catch(e => console.error);
  },

  /**
   * Initiate gcli screenshot command on selected node
   */
  screenshotNode: function () {
    CommandUtils.createRequisition(this._target, {
      environment: CommandUtils.createEnvironment(this, "_target")
    }).then(requisition => {
      // Bug 1180314 -  CssSelector might contain white space so need to make sure it is
      // passed to screenshot as a single parameter.  More work *might* be needed if
      // CssSelector could contain escaped single- or double-quotes, backslashes, etc.
      requisition.updateExec("screenshot --selector '" + this.selectionCssSelector + "'");
    });
  },

  /**
   * Scroll the node into view.
   */
  scrollNodeIntoView: function () {
    if (!this.selection.isNode()) {
      return;
    }

    this.selection.nodeFront.scrollIntoView();
  },

  /**
   * Duplicate the selected node
   */
  duplicateNode: function () {
    let selection = this.selection;
    if (!selection.isElementNode() ||
        selection.isRoot() ||
        selection.isAnonymousNode() ||
        selection.isPseudoElementNode()) {
      return;
    }
    this.walker.duplicateNode(selection.nodeFront).catch(e => console.error(e));
  },

  /**
   * Delete the selected node.
   */
  deleteNode: function () {
    if (!this.selection.isNode() ||
         this.selection.isRoot()) {
      return;
    }

    // If the markup panel is active, use the markup panel to delete
    // the node, making this an undoable action.
    if (this.markup) {
      this.markup.deleteNode(this.selection.nodeFront);
    } else {
      // remove the node from content
      this.walker.removeNode(this.selection.nodeFront);
    }
  },

  /**
   * Add attribute to node.
   * Used for node context menu and shouldn't be called directly.
   */
  onAddAttribute: function () {
    let container = this.markup.getContainer(this.selection.nodeFront);
    container.addAttribute();
  },

  /**
   * Edit attribute for node.
   * Used for node context menu and shouldn't be called directly.
   */
  onEditAttribute: function () {
    let container = this.markup.getContainer(this.selection.nodeFront);
    container.editAttribute(this.nodeMenuTriggerInfo.name);
  },

  /**
   * Remove attribute from node.
   * Used for node context menu and shouldn't be called directly.
   */
  onRemoveAttribute: function () {
    let container = this.markup.getContainer(this.selection.nodeFront);
    container.removeAttribute(this.nodeMenuTriggerInfo.name);
  },

  expandNode: function () {
    this.markup.expandAll(this.selection.nodeFront);
  },

  collapseNode: function () {
    this.markup.collapseNode(this.selection.nodeFront);
  },

  /**
   * This method is here for the benefit of the node-menu-link-follow menu item
   * in the inspector contextual-menu.
   */
  onFollowLink: function () {
    let type = this.contextMenuTarget.dataset.type;
    let link = this.contextMenuTarget.dataset.link;

    this.followAttributeLink(type, link);
  },

  /**
   * Given a type and link found in a node's attribute in the markup-view,
   * attempt to follow that link (which may result in opening a new tab, the
   * style editor or debugger).
   */
  followAttributeLink: function (type, link) {
    if (!type || !link) {
      return;
    }

    if (type === "uri" || type === "cssresource" || type === "jsresource") {
      // Open link in a new tab.
      // When the inspector menu was setup on click (see _getNodeLinkMenuItems), we
      // already checked that resolveRelativeURL existed.
      this.inspector.resolveRelativeURL(
        link, this.selection.nodeFront).then(url => {
          if (type === "uri") {
            let browserWin = this.target.tab.ownerDocument.defaultView;
            browserWin.openUILinkIn(url, "tab");
          } else if (type === "cssresource") {
            return this.toolbox.viewSourceInStyleEditor(url);
          } else if (type === "jsresource") {
            return this.toolbox.viewSourceInDebugger(url);
          }
          return null;
        }).catch(e => console.error(e));
    } else if (type == "idref") {
      // Select the node in the same document.
      this.walker.document(this.selection.nodeFront).then(doc => {
        return this.walker.querySelector(doc, "#" + CSS.escape(link)).then(node => {
          if (!node) {
            this.emit("idref-attribute-link-failed");
            return;
          }
          this.selection.setNodeFront(node);
        });
      }).catch(e => console.error(e));
    }
  },

  /**
   * This method is here for the benefit of the node-menu-link-copy menu item
   * in the inspector contextual-menu.
   */
  onCopyLink: function () {
    let link = this.contextMenuTarget.dataset.link;

    this.copyAttributeLink(link);
  },

  /**
   * This method is here for the benefit of copying links.
   */
  copyAttributeLink: function (link) {
    // When the inspector menu was setup on click (see _getNodeLinkMenuItems), we
    // already checked that resolveRelativeURL existed.
    this.inspector.resolveRelativeURL(link, this.selection.nodeFront).then(url => {
      clipboardHelper.copyString(url);
    }, console.error);
  }
};

// URL constructor doesn't support chrome: scheme
let href = window.location.href.replace(/chrome:/, "http://");
let url = new window.URL(href);

// Only use this method to attach the toolbox if some query parameters are given
if (url.search.length > 1) {
  const { targetFromURL } = require("devtools/client/framework/target-from-url");
  const { attachThread } = require("devtools/client/framework/attach-thread");
  const { BrowserLoader } =
    Cu.import("resource://devtools/client/shared/browser-loader.js", {});

  const { Selection } = require("devtools/client/framework/selection");
  const { InspectorFront } = require("devtools/shared/fronts/inspector");
  const { getHighlighterUtils } = require("devtools/client/framework/toolbox-highlighter-utils");

  Task.spawn(function* () {
    let target = yield targetFromURL(url);

    let notImplemented = function () {
      throw new Error("Not implemented in a tab");
    };
    let fakeToolbox = {
      target,
      hostType: "bottom",
      doc: window.document,
      win: window,
      on() {}, emit() {}, off() {},
      initInspector() {},
      browserRequire: BrowserLoader({
        window: window,
        useOnlyShared: true
      }).require,
      get React() {
        return this.browserRequire("devtools/client/shared/vendor/react");
      },
      get ReactDOM() {
        return this.browserRequire("devtools/client/shared/vendor/react-dom");
      },
      isToolRegistered() {
        return false;
      },
      currentToolId: "inspector",
      getCurrentPanel() {
        return "inspector";
      },
      get textboxContextMenuPopup() {
        notImplemented();
      },
      getPanel: notImplemented,
      openSplitConsole: notImplemented,
      viewCssSourceInStyleEditor: notImplemented,
      viewJsSourceInDebugger: notImplemented,
      viewSource: notImplemented,
      viewSourceInDebugger: notImplemented,
      viewSourceInStyleEditor: notImplemented,

      // For attachThread:
      highlightTool() {},
      unhighlightTool() {},
      selectTool() {},
      raise() {},
      getNotificationBox() {}
    };

    // attachThread also expect a toolbox as argument
    fakeToolbox.threadClient = yield attachThread(fakeToolbox);

    let inspector = InspectorFront(target.client, target.form);
    let showAllAnonymousContent =
      Services.prefs.getBoolPref("devtools.inspector.showAllAnonymousContent");
    let walker = yield inspector.getWalker({ showAllAnonymousContent });
    let selection = new Selection(walker);
    let highlighter = yield inspector.getHighlighter(false);

    fakeToolbox.inspector = inspector;
    fakeToolbox.walker = walker;
    fakeToolbox.selection = selection;
    fakeToolbox.highlighter = highlighter;
    fakeToolbox.highlighterUtils = getHighlighterUtils(fakeToolbox);

    let inspectorUI = new Inspector(fakeToolbox);
    inspectorUI.init();
  }).then(null, e => {
    window.alert("Unable to start the inspector:" + e.message + "\n" + e.stack);
  });
}
