/* 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/. */

"use strict";

const { DevToolsShim } = ChromeUtils.importESModule(
  "chrome://devtools-startup/content/DevToolsShim.sys.mjs"
);

const { DEFAULT_SANDBOX_NAME } = ChromeUtils.importESModule(
  "resource://devtools/shared/loader/Loader.sys.mjs"
);

const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
  BrowserToolboxLauncher:
    "resource://devtools/client/framework/browser-toolbox/Launcher.sys.mjs",
});

loader.lazyRequireGetter(
  this,
  "LocalTabCommandsFactory",
  "resource://devtools/client/framework/local-tab-commands-factory.js",
  true
);
loader.lazyRequireGetter(
  this,
  "CommandsFactory",
  "resource://devtools/shared/commands/commands-factory.js",
  true
);
loader.lazyRequireGetter(
  this,
  "ToolboxHostManager",
  "resource://devtools/client/framework/toolbox-host-manager.js",
  true
);
loader.lazyRequireGetter(
  this,
  "BrowserConsoleManager",
  "resource://devtools/client/webconsole/browser-console-manager.js",
  true
);
loader.lazyRequireGetter(
  this,
  "Toolbox",
  "resource://devtools/client/framework/toolbox.js",
  true
);

loader.lazyRequireGetter(
  this,
  "Telemetry",
  "resource://devtools/client/shared/telemetry.js"
);

const {
  defaultTools: DefaultTools,
  defaultThemes: DefaultThemes,
} = require("resource://devtools/client/definitions.js");
const EventEmitter = require("resource://devtools/shared/event-emitter.js");
const {
  getTheme,
  setTheme,
  getAutoTheme,
  addThemeObserver,
  removeThemeObserver,
} = require("resource://devtools/client/shared/theme.js");

const FORBIDDEN_IDS = new Set(["toolbox", ""]);
const MAX_ORDINAL = 99;
const POPUP_DEBUG_PREF = "devtools.popups.debug";
const DEVTOOLS_ALWAYS_ON_TOP = "devtools.toolbox.alwaysOnTop";

/**
 * DevTools is a class that represents a set of developer tools, it holds a
 * set of tools and keeps track of open toolboxes in the browser.
 */
function DevTools() {
  // We should be careful to always load a unique instance of this module:
  // - only in the parent process
  // - only in the "shared JSM global" spawn by mozJSModuleLoader
  //   The server codebase typically use another global named "DevTools global",
  //   which will load duplicated instances of all the modules -or- another
  //   DevTools module loader named "DevTools (Server Module loader)".
  //   Also the realm location is appended the loading callsite, so only check
  //   the beginning of the string.
  if (
    Services.appinfo.processType != Services.appinfo.PROCESS_TYPE_DEFAULT ||
    !Cu.getRealmLocation(globalThis).startsWith(DEFAULT_SANDBOX_NAME)
  ) {
    throw new Error(
      "This module should be loaded in the parent process only, in the shared global."
    );
  }

  this._tools = new Map(); // Map<toolId, tool>
  this._themes = new Map(); // Map<themeId, theme>
  this._toolboxesPerCommands = new Map(); // Map<commands, toolbox>
  // List of toolboxes that are still in process of creation
  this._creatingToolboxes = new Map(); // Map<commands, toolbox Promise>

  EventEmitter.decorate(this);
  this._telemetry = new Telemetry();
  this._telemetry.setEventRecordingEnabled(true);

  // List of all commands of debugged local Web Extension.
  this._commandsPromiseByWebExtId = new Map(); // Map<extensionId, commands>

  // Listen for changes to the theme pref.
  this._onThemeChanged = this._onThemeChanged.bind(this);
  addThemeObserver(this._onThemeChanged);

  // This is important step in initialization codepath where we are going to
  // start registering all default tools and themes: create menuitems, keys, emit
  // related events.
  this.registerDefaults();

  // Register this DevTools instance on the DevToolsShim, which is used by non-devtools
  // code to interact with DevTools.
  DevToolsShim.register(this);
}

DevTools.prototype = {
  // The windowtype of the main window, used in various tools. This may be set
  // to something different by other gecko apps.
  chromeWindowType: "navigator:browser",

  registerDefaults() {
    // Ensure registering items in the sorted order (getDefault* functions
    // return sorted lists)
    this.getDefaultTools().forEach(definition => this.registerTool(definition));
    this.getDefaultThemes().forEach(definition =>
      this.registerTheme(definition)
    );
  },

  unregisterDefaults() {
    for (const definition of this.getToolDefinitionArray()) {
      this.unregisterTool(definition.id);
    }
    for (const definition of this.getThemeDefinitionArray()) {
      this.unregisterTheme(definition.id);
    }
  },

  /**
   * Register a new developer tool.
   *
   * A definition is a light object that holds different information about a
   * developer tool. This object is not supposed to have any operational code.
   * See it as a "manifest".
   * The only actual code lives in the build() function, which will be used to
   * start an instance of this tool.
   *
   * Each toolDefinition has the following properties:
   * - id: Unique identifier for this tool (string|required)
   * - visibilityswitch: Property name to allow us to hide this tool from the
   *                     DevTools Toolbox.
   *                     A falsy value indicates that it cannot be hidden.
   * - icon: URL pointing to a graphic which will be used as the src for an
   *         16x16 img tag (string|required)
   * - url: URL pointing to a XUL/XHTML document containing the user interface
   *        (string|required)
   * - label: Localized name for the tool to be displayed to the user
   *          (string|required)
   * - hideInOptions: Boolean indicating whether or not this tool should be
                      shown in toolbox options or not. Defaults to false.
   *                  (boolean)
   * - build: Function that takes an iframe, which has been populated with the
   *          markup from |url|, and also the toolbox containing the panel.
   *          And returns an instance of ToolPanel (function|required)
   */
  registerTool(toolDefinition) {
    const toolId = toolDefinition.id;

    if (!toolId || FORBIDDEN_IDS.has(toolId)) {
      throw new Error("Invalid definition.id");
    }

    // Make sure that additional tools will always be able to be hidden.
    // When being called from main.js, defaultTools has not yet been exported.
    // But, we can assume that in this case, it is a default tool.
    if (!DefaultTools.includes(toolDefinition)) {
      toolDefinition.visibilityswitch = "devtools." + toolId + ".enabled";
    }

    this._tools.set(toolId, toolDefinition);

    this.emit("tool-registered", toolId);
  },

  /**
   * Removes all tools that match the given |toolId|
   * Needed so that add-ons can remove themselves when they are deactivated
   *
   * @param {string} toolId
   *        The id of the tool to unregister.
   * @param {boolean} isQuitApplication
   *        true to indicate that the call is due to app quit, so we should not
   *        cause a cascade of costly events
   */
  unregisterTool(toolId, isQuitApplication) {
    this._tools.delete(toolId);

    if (!isQuitApplication) {
      this.emit("tool-unregistered", toolId);
    }
  },

  /**
   * Sorting function used for sorting tools based on their ordinals.
   */
  ordinalSort(d1, d2) {
    const o1 = typeof d1.ordinal == "number" ? d1.ordinal : MAX_ORDINAL;
    const o2 = typeof d2.ordinal == "number" ? d2.ordinal : MAX_ORDINAL;
    return o1 - o2;
  },

  getDefaultTools() {
    return DefaultTools.sort(this.ordinalSort);
  },

  getAdditionalTools() {
    const tools = [];
    for (const [, value] of this._tools) {
      if (!DefaultTools.includes(value)) {
        tools.push(value);
      }
    }
    return tools.sort(this.ordinalSort);
  },

  getDefaultThemes() {
    return DefaultThemes.sort(this.ordinalSort);
  },

  /**
   * Get a tool definition if it exists and is enabled.
   *
   * @param {string} toolId
   *        The id of the tool to show
   *
   * @return {ToolDefinition|null} tool
   *         The ToolDefinition for the id or null.
   */
  getToolDefinition(toolId) {
    const tool = this._tools.get(toolId);
    if (!tool) {
      return null;
    } else if (!tool.visibilityswitch) {
      return tool;
    }

    const enabled = Services.prefs.getBoolPref(tool.visibilityswitch, true);

    return enabled ? tool : null;
  },

  /**
   * Allow ToolBoxes to get at the list of tools that they should populate
   * themselves with.
   *
   * @return {Map} tools
   *         A map of the the tool definitions registered in this instance
   */
  getToolDefinitionMap() {
    const tools = new Map();

    for (const [id, definition] of this._tools) {
      if (this.getToolDefinition(id)) {
        tools.set(id, definition);
      }
    }

    return tools;
  },

  /**
   * Tools have an inherent ordering that can't be represented in a Map so
   * getToolDefinitionArray provides an alternative representation of the
   * definitions sorted by ordinal value.
   *
   * @return {Array} tools
   *         A sorted array of the tool definitions registered in this instance
   */
  getToolDefinitionArray() {
    const definitions = [];

    for (const [id, definition] of this._tools) {
      if (this.getToolDefinition(id)) {
        definitions.push(definition);
      }
    }

    return definitions.sort(this.ordinalSort);
  },

  /**
   * Returns the name of the current theme for devtools.
   *
   * @return {string} theme
   *         The name of the current devtools theme.
   */
  getTheme() {
    return getTheme();
  },

  /**
   * Returns the name of the default (auto) theme for devtools.
   *
   * @return {string} theme
   */
  getAutoTheme() {
    return getAutoTheme();
  },

  /**
   * Called when the developer tools theme changes.
   */
  _onThemeChanged() {
    this.emit("theme-changed", getTheme());
  },

  /**
   * Register a new theme for developer tools toolbox.
   *
   * A definition is a light object that holds various information about a
   * theme.
   *
   * Each themeDefinition has the following properties:
   * - id: Unique identifier for this theme (string|required)
   * - label: Localized name for the theme to be displayed to the user
   *          (string|required)
   * - stylesheets: Array of URLs pointing to a CSS document(s) containing
   *                the theme style rules (array|required)
   * - classList: Array of class names identifying the theme within a document.
   *              These names are set to document element when applying
   *              the theme (array|required)
   * - onApply: Function that is executed by the framework when the theme
   *            is applied. The function takes the current iframe window
   *            and the previous theme id as arguments (function)
   * - onUnapply: Function that is executed by the framework when the theme
   *            is unapplied. The function takes the current iframe window
   *            and the new theme id as arguments (function)
   */
  registerTheme(themeDefinition) {
    const themeId = themeDefinition.id;

    if (!themeId) {
      throw new Error("Invalid theme id");
    }

    if (this._themes.get(themeId)) {
      throw new Error("Theme with the same id is already registered");
    }

    this._themes.set(themeId, themeDefinition);

    this.emit("theme-registered", themeId);
  },

  /**
   * Removes an existing theme from the list of registered themes.
   * Needed so that add-ons can remove themselves when they are deactivated
   *
   * @param {string|object} theme
   *        Definition or the id of the theme to unregister.
   */
  unregisterTheme(theme) {
    let themeId = null;
    if (typeof theme == "string") {
      themeId = theme;
      theme = this._themes.get(theme);
    } else {
      themeId = theme.id;
    }

    const currTheme = getTheme();

    // Note that we can't check if `theme` is an item
    // of `DefaultThemes` as we end up reloading definitions
    // module and end up with different theme objects
    const isCoreTheme = DefaultThemes.some(t => t.id === themeId);

    // Reset the theme if an extension theme that's currently applied
    // is being removed.
    // Ignore shutdown since addons get disabled during that time.
    if (
      !Services.startup.shuttingDown &&
      !isCoreTheme &&
      theme.id == currTheme
    ) {
      setTheme("auto");

      this.emit("theme-unregistered", theme);
    }

    this._themes.delete(themeId);
  },

  /**
   * Get a theme definition if it exists.
   *
   * @param {string} themeId
   *        The id of the theme
   *
   * @return {ThemeDefinition|null} theme
   *         The ThemeDefinition for the id or null.
   */
  getThemeDefinition(themeId) {
    const theme = this._themes.get(themeId);
    if (!theme) {
      return null;
    }
    return theme;
  },

  /**
   * Get map of registered themes.
   *
   * @return {Map} themes
   *         A map of the the theme definitions registered in this instance
   */
  getThemeDefinitionMap() {
    const themes = new Map();

    for (const [id, definition] of this._themes) {
      if (this.getThemeDefinition(id)) {
        themes.set(id, definition);
      }
    }

    return themes;
  },

  /**
   * Get registered themes definitions sorted by ordinal value.
   *
   * @return {Array} themes
   *         A sorted array of the theme definitions registered in this instance
   */
  getThemeDefinitionArray() {
    const definitions = [];

    for (const [id, definition] of this._themes) {
      if (this.getThemeDefinition(id)) {
        definitions.push(definition);
      }
    }

    return definitions.sort(this.ordinalSort);
  },

  /**
   * Called from SessionStore.sys.mjs in mozilla-central when saving the current state.
   *
   * @param {Object} state
   *                 A SessionStore state object that gets modified by reference
   */
  saveDevToolsSession(state) {
    state.browserConsole =
      BrowserConsoleManager.getBrowserConsoleSessionState();
    state.browserToolbox =
      lazy.BrowserToolboxLauncher.getBrowserToolboxSessionState();
  },

  /**
   * Restore the devtools session state as provided by SessionStore.
   */
  async restoreDevToolsSession({ browserConsole, browserToolbox }) {
    if (browserToolbox) {
      lazy.BrowserToolboxLauncher.init();
    }

    if (browserConsole && !BrowserConsoleManager.getBrowserConsole()) {
      await BrowserConsoleManager.toggleBrowserConsole();
    }
  },

  /**
   * Boolean, true, if we never opened a toolbox.
   * Used to implement the telemetry tracking toolbox opening.
   */
  _firstShowToolbox: true,

  /**
   * Show a Toolbox for a given "commands" (either by creating a new one, or if a
   * toolbox already exists for the commands, by bringing to the front the
   * existing one).
   *
   * If a Toolbox already exists, we will still update it based on some of the
   * provided parameters:
   *   - if |toolId| is provided then the toolbox will switch to the specified
   *     tool.
   *   - if |hostType| is provided then the toolbox will be switched to the
   *     specified HostType.
   *
   * @param {Commands Object} commands
   *         The commands object which designates which context the toolbox will debug
   * @param {Object}
   *        - {String} toolId
   *          The id of the tool to show
   *        - {Toolbox.HostType} hostType
   *          The type of host (bottom, window, left, right)
   *        - {object} hostOptions
   *          Options for host specifically
   *        - {Number} startTime
   *          Indicates the time at which the user event related to
   *          this toolbox opening started. This is a `Cu.now()` timing.
   *        - {string} reason
   *          Reason the tool was opened
   *        - {boolean} raise
   *          Whether we need to raise the toolbox or not.
   *
   * @return {Toolbox} toolbox
   *        The toolbox that was opened
   */
  async showToolbox(
    commands,
    {
      toolId,
      hostType,
      startTime,
      raise = true,
      reason = "toolbox_show",
      hostOptions,
    } = {}
  ) {
    let toolbox = this._toolboxesPerCommands.get(commands);

    if (toolbox) {
      if (hostType != null && toolbox.hostType != hostType) {
        await toolbox.switchHost(hostType);
      }

      if (toolId != null) {
        // selectTool will either select the tool if not currently selected, or wait for
        // the tool to be loaded if needed.
        await toolbox.selectTool(toolId, reason);
      }

      if (raise) {
        await toolbox.raise();
      }
    } else {
      // Toolbox creation is async, we have to be careful about races.
      // Check if we are already waiting for a Toolbox for the provided
      // commands before creating a new one.
      const promise = this._creatingToolboxes.get(commands);
      if (promise) {
        return promise;
      }
      const toolboxPromise = this._createToolbox(
        commands,
        toolId,
        hostType,
        hostOptions
      );
      this._creatingToolboxes.set(commands, toolboxPromise);
      toolbox = await toolboxPromise;
      this._creatingToolboxes.delete(commands);

      if (startTime) {
        this.logToolboxOpenTime(toolbox, startTime);
      }
      this._firstShowToolbox = false;
    }

    // We send the "enter" width here to ensure it is always sent *after*
    // the "open" event.
    const width = Math.ceil(toolbox.win.outerWidth / 50) * 50;
    const panelName = this.makeToolIdHumanReadable(
      toolId || toolbox.defaultToolId
    );
    this._telemetry.addEventProperty(
      toolbox,
      "enter",
      panelName,
      null,
      "width",
      width
    );

    return toolbox;
  },

  /**
   * Show the toolbox for a given tab. If a toolbox already exists for this tab
   * the existing toolbox will be raised. Otherwise a new toolbox is created.
   *
   * Relies on `showToolbox`, see its jsDoc for additional information and
   * arguments description.
   *
   * Also used by 3rd party tools (eg wptrunner) and exposed by
   * DevToolsShim.sys.mjs.
   *
   * @param {XULTab} tab
   *        The tab the toolbox will debug
   * @param {Object} options
   *        Various options that will be forwarded to `showToolbox`. See the
   *        JSDoc on this method.
   */
  async showToolboxForTab(
    tab,
    { toolId, hostType, startTime, raise, reason, hostOptions } = {}
  ) {
    // Popups are debugged via the toolbox of their opener document/tab.
    // So avoid opening dedicated toolbox for them.
    if (
      tab.linkedBrowser.browsingContext.opener &&
      Services.prefs.getBoolPref(POPUP_DEBUG_PREF)
    ) {
      const openerTab = tab.ownerGlobal.gBrowser.getTabForBrowser(
        tab.linkedBrowser.browsingContext.opener.embedderElement
      );
      const openerCommands = await LocalTabCommandsFactory.getCommandsForTab(
        openerTab
      );
      if (this.getToolboxForCommands(openerCommands)) {
        console.log(
          "Can't open a toolbox for this document as this is debugged from its opener tab"
        );
        return null;
      }
    }
    const commands = await LocalTabCommandsFactory.createCommandsForTab(tab);
    return this.showToolbox(commands, {
      toolId,
      hostType,
      startTime,
      raise,
      reason,
      hostOptions,
    });
  },

  /**
   * Open a Toolbox in a dedicated top-level window for debugging a local WebExtension.
   * This will re-open a previously opened toolbox if we try to re-debug the same extension.
   *
   * Note that this will spawn a new DevToolsClient.
   *
   * @param {String} extensionId
   *        ID of the extension to debug.
   * @param {Object} (optional)
   *        - {String} toolId
   *          The id of the tool to show
   */
  async showToolboxForWebExtension(extensionId, { toolId } = {}) {
    // Ensure spawning only one commands instance per extension at a time by caching its commands.
    // showToolbox will later reopen the previously opened toolbox if called with the same
    // commands.
    let commandsPromise = this._commandsPromiseByWebExtId.get(extensionId);
    if (!commandsPromise) {
      commandsPromise = CommandsFactory.forAddon(extensionId);
      this._commandsPromiseByWebExtId.set(extensionId, commandsPromise);
    }
    const commands = await commandsPromise;
    commands.client.once("closed").then(() => {
      this._commandsPromiseByWebExtId.delete(extensionId);
    });

    return this.showToolbox(commands, {
      hostType: Toolbox.HostType.WINDOW,
      hostOptions: {
        // The toolbox is always displayed on top so that we can keep
        // the DevTools visible while interacting with the Firefox window.
        alwaysOnTop: Services.prefs.getBoolPref(DEVTOOLS_ALWAYS_ON_TOP, false),
      },
      toolId,
    });
  },

  /**
   * Log telemetry related to toolbox opening.
   * Two distinct probes are logged. One for cold startup, when we open the very first
   * toolbox. This one includes devtools framework loading. And a second one for all
   * subsequent toolbox opening, which should all be faster.
   * These two probes are indexed by Tool ID.
   *
   * @param {String} toolbox
   *        Toolbox instance.
   * @param {Number} startTime
   *        Indicates the time at which the user event related to the toolbox
   *        opening started. This is a `Cu.now()` timing.
   */
  logToolboxOpenTime(toolbox, startTime) {
    const toolId = toolbox.currentToolId || toolbox.defaultToolId;
    const delay = Cu.now() - startTime;
    const panelName = this.makeToolIdHumanReadable(toolId);

    const telemetryKey = this._firstShowToolbox
      ? "DEVTOOLS_COLD_TOOLBOX_OPEN_DELAY_MS"
      : "DEVTOOLS_WARM_TOOLBOX_OPEN_DELAY_MS";
    this._telemetry.getKeyedHistogramById(telemetryKey).add(toolId, delay);

    const browserWin = toolbox.topWindow;
    this._telemetry.addEventProperty(
      browserWin,
      "open",
      "tools",
      null,
      "first_panel",
      panelName
    );
  },

  makeToolIdHumanReadable(toolId) {
    if (/^[0-9a-fA-F]{40}_temporary-addon/.test(toolId)) {
      return "temporary-addon";
    }

    let matches = toolId.match(
      /^_([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12})_/
    );
    if (matches && matches.length === 2) {
      return matches[1];
    }

    matches = toolId.match(/^_?(.*)-\d+-\d+-devtools-panel$/);
    if (matches && matches.length === 2) {
      return matches[1];
    }

    return toolId;
  },

  /**
   * Unconditionally create a new Toolbox instance for the provided commands.
   * See `showToolbox` for the arguments' jsdoc.
   */
  async _createToolbox(commands, toolId, hostType, hostOptions) {
    const manager = new ToolboxHostManager(commands, hostType, hostOptions);

    const toolbox = await manager.create(toolId);

    this._toolboxesPerCommands.set(commands, toolbox);

    toolbox.once("destroy", () => {
      this.emit("toolbox-destroy", toolbox);
    });

    toolbox.once("destroyed", () => {
      this._toolboxesPerCommands.delete(commands);
      this.emit("toolbox-destroyed", toolbox);
    });

    await toolbox.open();
    this.emit("toolbox-ready", toolbox);

    return toolbox;
  },

  /**
   * Return the toolbox for a given commands object.
   *
   * @param  {Commands Object} commands
   *         Debugging context commands that owns this toolbox
   *
   * @return {Toolbox} toolbox
   *         The toolbox that is debugging the given context designated by the commands
   */
  getToolboxForCommands(commands) {
    return this._toolboxesPerCommands.get(commands);
  },

  /**
   * TabDescriptorFront requires a synchronous method and don't have a reference to its
   * related commands object. So expose something handcrafted just for this.
   */
  getToolboxForDescriptorFront(descriptorFront) {
    for (const [commands, toolbox] of this._toolboxesPerCommands) {
      if (commands.descriptorFront == descriptorFront) {
        return toolbox;
      }
    }
    return null;
  },

  /**
   * Retrieve an existing toolbox for the provided tab if it was created before.
   * Returns null otherwise.
   *
   * @param {XULTab} tab
   *        The browser tab.
   * @return {Toolbox}
   *        Returns tab's toolbox object.
   */
  getToolboxForTab(tab) {
    return this.getToolboxes().find(
      t => t.commands.descriptorFront.localTab === tab
    );
  },

  /**
   * Close the toolbox for a given tab.
   *
   * @return {Promise} Returns a promise that resolves either:
   *         - immediately if no Toolbox was found
   *         - or after toolbox.destroy() resolved if a Toolbox was found
   */
  async closeToolboxForTab(tab) {
    const commands = await LocalTabCommandsFactory.getCommandsForTab(tab);

    let toolbox = await this._creatingToolboxes.get(commands);
    if (!toolbox) {
      toolbox = this._toolboxesPerCommands.get(commands);
    }
    if (!toolbox) {
      return;
    }
    await toolbox.destroy();
  },

  /**
   * Compatibility layer for web-extensions. Used by DevToolsShim for
   * browser/components/extensions/ext-devtools.js
   *
   * web-extensions need to use dedicated instances of Commands and cannot reuse the
   * cached instances managed by DevTools.
   * Note that is will end up being cached in WebExtension codebase, via
   * DevToolsExtensionPageContextParent.getDevToolsCommands.
   */
  createCommandsForTabForWebExtension(tab) {
    return CommandsFactory.forTab(tab, { isWebExtension: true });
  },

  /**
   * Compatibility layer for web-extensions. Used by DevToolsShim for
   * toolkit/components/extensions/ext-c-toolkit.js
   */
  openBrowserConsole() {
    const {
      BrowserConsoleManager,
    } = require("resource://devtools/client/webconsole/browser-console-manager.js");
    BrowserConsoleManager.openBrowserConsoleOrFocus();
  },

  /**
   * Called from the DevToolsShim, used by nsContextMenu.js.
   *
   * @param {XULTab} tab
   *        The browser tab on which inspect node was used.
   * @param {ElementIdentifier} domReference
   *        Identifier generated by ContentDOMReference. It is a unique pair of
   *        BrowsingContext ID and a numeric ID.
   * @param {Number} startTime
   *        Optional, indicates the time at which the user event related to this node
   *        inspection started. This is a `Cu.now()` timing.
   * @return {Promise} a promise that resolves when the node is selected in the inspector
   *         markup view.
   */
  async inspectNode(tab, domReference, startTime) {
    const toolbox = await gDevTools.showToolboxForTab(tab, {
      toolId: "inspector",
      startTime,
      reason: "inspect_dom",
    });
    const inspector = toolbox.getCurrentPanel();

    const nodeFront =
      await inspector.inspectorFront.getNodeActorFromContentDomReference(
        domReference
      );
    if (!nodeFront) {
      return;
    }

    // "new-node-front" tells us when the node has been selected, whether the
    // browser is remote or not.
    const onNewNode = inspector.selection.once("new-node-front");
    // Select the final node
    inspector.selection.setNodeFront(nodeFront, {
      reason: "browser-context-menu",
    });

    await onNewNode;
    // Now that the node has been selected, wait until the inspector is
    // fully updated.
    await inspector.once("inspector-updated");
  },

  /**
   * Called from the DevToolsShim, used by nsContextMenu.js.
   *
   * @param {XULTab} tab
   *        The browser tab on which inspect accessibility was used.
   * @param {ElementIdentifier} domReference
   *        Identifier generated by ContentDOMReference. It is a unique pair of
   *        BrowsingContext ID and a numeric ID.
   * @param {Number} startTime
   *        Optional, indicates the time at which the user event related to this
   *        node inspection started. This is a `Cu.now()` timing.
   * @return {Promise} a promise that resolves when the accessible object is
   *         selected in the accessibility inspector.
   */
  async inspectA11Y(tab, domReference, startTime) {
    const toolbox = await gDevTools.showToolboxForTab(tab, {
      toolId: "accessibility",
      startTime,
    });
    const inspectorFront = await toolbox.target.getFront("inspector");
    const nodeFront = await inspectorFront.getNodeActorFromContentDomReference(
      domReference
    );
    if (!nodeFront) {
      return;
    }

    // Select the accessible object in the panel and wait for the event that
    // tells us it has been done.
    const a11yPanel = toolbox.getCurrentPanel();
    const onSelected = a11yPanel.once("new-accessible-front-selected");
    a11yPanel.selectAccessibleForNode(nodeFront, "browser-context-menu");
    await onSelected;
  },

  /**
   * Either the DevTools Loader has been destroyed or firefox is shutting down.
   * @param {boolean} shuttingDown
   *        True if firefox is currently shutting down. We may prevent doing
   *        some cleanups to speed it up. Otherwise everything need to be
   *        cleaned up in order to be able to load devtools again.
   */
  destroy({ shuttingDown }) {
    // Do not cleanup everything during firefox shutdown.
    if (!shuttingDown) {
      for (const [, toolbox] of this._toolboxesPerCommands) {
        toolbox.destroy();
      }
    }

    for (const [key] of this.getToolDefinitionMap()) {
      this.unregisterTool(key, true);
    }

    gDevTools.unregisterDefaults();

    removeThemeObserver(this._onThemeChanged);

    // Do not unregister devtools from the DevToolsShim if the destroy is caused by an
    // application shutdown. For instance SessionStore needs to save the Browser Toolbox
    // state on shutdown.
    if (!shuttingDown) {
      // Notify the DevToolsShim that DevTools are no longer available, particularly if
      // the destroy was caused by disabling/removing DevTools.
      DevToolsShim.unregister();
    }

    // Cleaning down the toolboxes: i.e.
    //   for (let [, toolbox] of this._toolboxesPerCommands) toolbox.destroy();
    // Is taken care of by the gDevToolsBrowser.forgetBrowserWindow
  },

  /**
   * Returns the array of the existing toolboxes.
   *
   * @return {Array<Toolbox>}
   *   An array of toolboxes.
   */
  getToolboxes() {
    return Array.from(this._toolboxesPerCommands.values());
  },

  /**
   * Returns whether the given tab has toolbox.
   *
   * @param {XULTab} tab
   *        The browser tab.
   * @return {boolean}
   *        Returns true if the tab has toolbox.
   */
  hasToolboxForTab(tab) {
    return this.getToolboxes().some(
      t => t.commands.descriptorFront.localTab === tab
    );
  },
};

const gDevTools = (exports.gDevTools = new DevTools());
