/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";

const lazy = {};

ChromeUtils.defineESModuleGetters(lazy, {
  CustomizableUI: "resource:///modules/CustomizableUI.sys.mjs",
  IPProtectionPanel:
    "resource:///modules/ipprotection/IPProtectionPanel.sys.mjs",
});

const FXA_WIDGET_ID = "fxa-toolbar-menu-button";
const EXT_WIDGET_ID = "unified-extensions-button";

/**
 * IPProtectionWidget is the class for the singleton IPProtection, which
 * exposes init and uninit for app startup.
 *
 * It is a minimal manager for creating and removing a CustomizableUI widget
 * for IP protection features.
 *
 * It maintains the state of the panels and updates them when the
 * panel is shown or hidden.
 */
class IPProtectionWidget {
  static WIDGET_ID = "ipprotection-button";
  static PANEL_ID = "PanelUI-ipprotection";

  static ENABLED_PREF = "browser.ipProtection.enabled";

  #enabled = true;
  #created = false;
  #destroyed = false;
  #panels = new WeakMap();

  constructor() {
    this.updateEnabled = this.#updateEnabled.bind(this);
  }

  /**
   * Creates the widget if the feature is enabled and
   * the widget has not already been created.
   *
   * @param {Window} window - new browser window.
   */
  init(window) {
    if (!this.isEnabled) {
      return;
    }

    if (!this.#created) {
      this.#createWidget();
    }

    lazy.IPProtectionPanel.loadCustomElements(window);
  }

  /**
   * Destroys the widget and prevents any updates.
   */
  uninit() {
    this.#destroyWidget();
    this.#destroyed = true;
  }

  /**
   * Opens the panel in the given window.
   *
   * @param {Window} window - which window to open the panel in.
   * @returns {Promise<void>}
   */
  async openPanel(window) {
    if (!this.#created || !window?.PanelUI) {
      return;
    }

    let widget = lazy.CustomizableUI.getWidget(IPProtectionWidget.WIDGET_ID);
    let anchor = widget.forWindow(window).anchor;
    await window.PanelUI.showSubView(IPProtectionWidget.PANEL_ID, anchor);
  }

  /**
   * Creates the CustomizableUI widget.
   */
  #createWidget() {
    const onViewShowing = this.#onViewShowing.bind(this);
    const onViewHiding = this.#onViewHiding.bind(this);
    const onBeforeCreated = this.#onBeforeCreated.bind(this);
    const onCreated = this.#onCreated.bind(this);
    lazy.CustomizableUI.createWidget({
      id: IPProtectionWidget.WIDGET_ID,
      l10nId: IPProtectionWidget.WIDGET_ID,
      type: "view",
      viewId: IPProtectionWidget.PANEL_ID,
      overflows: false,
      onViewShowing,
      onViewHiding,
      onBeforeCreated,
      onCreated,
    });

    this.#placeWidget();

    this.#created = true;
  }

  /**
   * Places the widget in the nav bar, next to the FxA widget.
   */
  #placeWidget() {
    let prevWidget = lazy.CustomizableUI.getPlacementOfWidget(FXA_WIDGET_ID);
    if (!prevWidget) {
      // Fallback to unremovable extensions button if fxa button isn't available.
      prevWidget = lazy.CustomizableUI.getPlacementOfWidget(EXT_WIDGET_ID);
    }

    lazy.CustomizableUI.addWidgetToArea(
      IPProtectionWidget.WIDGET_ID,
      lazy.CustomizableUI.AREA_NAVBAR,
      prevWidget.position - 1
    );
  }

  /**
   * Destroys the widget if it has been created.
   *
   * This will not remove the pref listeners, so the widget
   * can be recreated later.
   */
  #destroyWidget() {
    if (!this.#created) {
      return;
    }
    this.#destroyPanels();
    lazy.CustomizableUI.destroyWidget(IPProtectionWidget.WIDGET_ID);
    this.#created = false;
  }

  /**
   * Remove all panels.
   */
  #destroyPanels() {
    let panels = ChromeUtils.nondeterministicGetWeakMapKeys(this.#panels);
    for (let panel of panels) {
      this.#panels.get(panel).destroy();
    }
    this.#panels = new WeakMap();
  }

  /**
   * Sets whether the feature pref is enabled and not destroyed.
   *
   * If enabled, creates the widget if it hasn't been created yet.
   * If not enabled, destroys the widget if it has been created.
   */
  #updateEnabled() {
    this.#enabled = this.isEnabled && !this.#destroyed;
    if (this.#enabled && !this.#created) {
      this.#createWidget();
    } else if (!this.#enabled && this.#created) {
      this.#destroyWidget();
    }
  }

  /**
   * Updates the state of the panel before it is shown.
   *
   * @param {Event} event - the panel shown.
   */
  #onViewShowing(event) {
    let { ownerGlobal } = event.target;
    if (this.#panels.has(ownerGlobal)) {
      let panel = this.#panels.get(ownerGlobal);
      panel.showing(event.target);
    }
  }

  /**
   * Updates the panels visibility.
   *
   * @param {Event} event - the panel hidden.
   */
  #onViewHiding(event) {
    let { ownerGlobal } = event.target;
    if (this.#panels.has(ownerGlobal)) {
      let panel = this.#panels.get(ownerGlobal);
      panel.hiding();
    }
  }

  /**
   * Creates a new IPProtectionPanel for a browser window.
   *
   * @param {Document} doc - the document containing the panel.
   */
  #onBeforeCreated(doc) {
    let { ownerGlobal } = doc;
    let panel = new lazy.IPProtectionPanel(ownerGlobal);
    this.#panels.set(ownerGlobal, panel);
  }

  /**
   * Gets the toolbaritem after the widget has been created and
   * adds content to the panel.
   *
   * @param {XULElement} _toolbaritem - the widget toolbaritem.
   */
  #onCreated(_toolbaritem) {}
}

const IPProtection = new IPProtectionWidget();

XPCOMUtils.defineLazyPreferenceGetter(
  IPProtection,
  "isEnabled",
  IPProtectionWidget.ENABLED_PREF,
  false,
  IPProtection.updateEnabled
);

export { IPProtection, IPProtectionWidget };