@navikt/ds-react/src/modal/dialog-polyfill.ts

React components from the Norwegian Labour and Welfare Administration.

/* eslint-disable no-var, object-shorthand */
// eslint-disable-next-line @typescript-eslint/ban-ts-comment
// @ts-nocheck

export const needPolyfill =
  typeof window !== "undefined" &&
  (window.HTMLDialogElement === undefined ||
    navigator.userAgent.includes("jsdom"));

// Copyright (c) 2013 The Chromium Authors. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//    * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//    * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//    * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

/**
 * Dispatches the passed event to both an "on<type>" handler as well as via the
 * normal dispatch operation. Does not bubble.
 *
 * @param {!EventTarget} target
 * @param {!Event} event
 * @return {boolean}
 */
function safeDispatchEvent(target, event) {
  var check = "on" + event.type.toLowerCase();
  if (typeof target[check] === "function") {
    target[check](event);
  }
  return target.dispatchEvent(event);
}

/**
 * Finds the nearest <dialog> from the passed element.
 *
 * @param {Element} el to search from
 * @return {HTMLDialogElement} dialog found
 */
function findNearestDialog(el) {
  while (el) {
    if (el.localName === "dialog") {
      return /** @type {HTMLDialogElement} */ el;
    }
    if (el.parentElement) {
      el = el.parentElement;
    } else if (el.parentNode) {
      el = el.parentNode.host;
    } else {
      el = null;
    }
  }
  return null;
}

/**
 * Blur the specified element, as long as it's not the HTML body element.
 * This works around an IE9/10 bug - blurring the body causes Windows to
 * blur the whole application.
 *
 * @param {Element} el to blur
 */
function safeBlur(el) {
  // Find the actual focused element when the active element is inside a shadow root
  while (el && el.shadowRoot && el.shadowRoot.activeElement) {
    el = el.shadowRoot.activeElement;
  }

  if (el && el.blur && el !== document.body) {
    el.blur();
  }
}

/**
 * @param {!NodeList} nodeList to search
 * @param {Node} node to find
 * @return {boolean} whether node is inside nodeList
 */
function inNodeList(nodeList, node) {
  for (var i = 0; i < nodeList.length; ++i) {
    if (nodeList[i] === node) {
      return true;
    }
  }
  return false;
}

/**
 * @param {HTMLFormElement} el to check
 * @return {boolean} whether this form has method="dialog"
 */
function isFormMethodDialog(el) {
  if (!el || !el.hasAttribute("method")) {
    return false;
  }
  return el.getAttribute("method").toLowerCase() === "dialog";
}

/**
 * @param {!DocumentFragment|!Element} hostElement
 * @return {?Element}
 */
function findFocusableElementWithin(hostElement) {
  // Note that this is 'any focusable area'. This list is probably not exhaustive, but the
  // alternative involves stepping through and trying to focus everything.
  var opts = ["button", "input", "keygen", "select", "textarea"];
  var query = opts.map(function (el) {
    return el + ":not([disabled])";
  });
  // TODO(samthor): tabindex values that are not numeric are not focusable.
  query.push('[tabindex]:not([disabled]):not([tabindex=""])'); // tabindex != "", not disabled
  var target = hostElement.querySelector(query.join(", "));

  if (!target && "attachShadow" in Element.prototype) {
    // If we haven't found a focusable target, see if the host element contains an element
    // which has a shadowRoot.
    // Recursively search for the first focusable item in shadow roots.
    var elems = hostElement.querySelectorAll("*");
    for (var i = 0; i < elems.length; i++) {
      if (elems[i].tagName && elems[i].shadowRoot) {
        target = findFocusableElementWithin(elems[i].shadowRoot);
        if (target) {
          break;
        }
      }
    }
  }
  return target;
}

/**
 * Determines if an element is attached to the DOM.
 * @param {Element} element to check
 * @return {boolean} whether the element is in DOM
 */
function isConnected(element) {
  return element.isConnected || document.body.contains(element);
}

/**
 * @param {!Event} event
 * @return {?Element}
 */
function findFormSubmitter(event) {
  if (event.submitter) {
    return event.submitter;
  }

  var form = event.target;
  if (!(form instanceof HTMLFormElement)) {
    return null;
  }

  var submitter = dialogPolyfill.formSubmitter;
  if (!submitter) {
    var target = event.target;
    var root = ("getRootNode" in target && target.getRootNode()) || document;
    submitter = root.activeElement;
  }

  if (!submitter || submitter.form !== form) {
    return null;
  }
  return submitter;
}

/**
 * @param {!Event} event
 */
function maybeHandleSubmit(event) {
  if (event.defaultPrevented) {
    return;
  }
  var form = /** @type {!HTMLFormElement} */ event.target;

  // We'd have a value if we clicked on an imagemap.
  var value = dialogPolyfill.imagemapUseValue;
  var submitter = findFormSubmitter(event);
  if (value === null && submitter) {
    value = submitter.value;
  }

  // There should always be a dialog as this handler is added specifically on them, but check just
  // in case.
  var dialog = findNearestDialog(form);
  if (!dialog) {
    return;
  }

  // Prefer formmethod on the button.
  var formmethod =
    (submitter && submitter.getAttribute("formmethod")) ||
    form.getAttribute("method");
  if (formmethod !== "dialog") {
    return;
  }
  event.preventDefault();

  if (value != null) {
    // nb. we explicitly check against null/undefined
    dialog.close(value);
  } else {
    dialog.close();
  }
}

/**
 * @param {!HTMLDialogElement} dialog to upgrade
 * @constructor
 */
function dialogPolyfillInfo(dialog) {
  this.dialog_ = dialog;
  this.replacedStyleTop_ = false;
  this.openAsModal_ = false;

  // Set a11y role. Browsers that support dialog implicitly know this already.
  if (!dialog.hasAttribute("role")) {
    dialog.setAttribute("role", "dialog");
  }

  dialog.show = this.show.bind(this);
  dialog.showModal = this.showModal.bind(this);
  dialog.close = this.close.bind(this);

  dialog.addEventListener("submit", maybeHandleSubmit, false);

  if (!("returnValue" in dialog)) {
    dialog.returnValue = "";
  }

  if ("MutationObserver" in window) {
    var mo = new MutationObserver(this.maybeHideModal.bind(this));
    mo.observe(dialog, { attributes: true, attributeFilter: ["open"] });
  } else {
    // IE10 and below support. Note that DOMNodeRemoved etc fire _before_ removal. They also
    // seem to fire even if the element was removed as part of a parent removal. Use the removed
    // events to force downgrade (useful if removed/immediately added).
    var removed = false;
    var cb = function () {
      removed ? this.downgradeModal() : this.maybeHideModal();
      removed = false;
    }.bind(this);
    var timeout: ReturnType<typeof setTimeout>;
    var delayModel = function (ev) {
      if (ev.target !== dialog) {
        return;
      } // not for a child element
      var cand = "DOMNodeRemoved";
      removed |= ev.type.substr(0, cand.length) === cand;
      window.clearTimeout(timeout);
      timeout = window.setTimeout(cb, 0);
    };
    ["DOMAttrModified", "DOMNodeRemoved", "DOMNodeRemovedFromDocument"].forEach(
      function (name) {
        dialog.addEventListener(name, delayModel);
      },
    );
  }
  // Note that the DOM is observed inside DialogManager while any dialog
  // is being displayed as a modal, to catch modal removal from the DOM.

  Object.defineProperty(dialog, "open", {
    set: this.setOpen.bind(this),
    get: dialog.hasAttribute.bind(dialog, "open"),
  });

  this.backdrop_ = document.createElement("div");
  this.backdrop_.className = "backdrop";
  this.backdrop_.addEventListener(
    "mouseup",
    this.backdropMouseEvent_.bind(this),
  );
  this.backdrop_.addEventListener(
    "mousedown",
    this.backdropMouseEvent_.bind(this),
  );
  this.backdrop_.addEventListener("click", this.backdropMouseEvent_.bind(this));
}

dialogPolyfillInfo.prototype = /** @type {HTMLDialogElement.prototype} */ {
  get dialog() {
    return this.dialog_;
  },

  /**
   * Maybe remove this dialog from the modal top layer. This is called when
   * a modal dialog may no longer be tenable, e.g., when the dialog is no
   * longer open or is no longer part of the DOM.
   */
  maybeHideModal: function () {
    if (this.dialog_.hasAttribute("open") && isConnected(this.dialog_)) {
      return;
    }
    this.downgradeModal();
  },

  /**
   * Remove this dialog from the modal top layer, leaving it as a non-modal.
   */
  downgradeModal: function () {
    if (!this.openAsModal_) {
      return;
    }
    this.openAsModal_ = false;
    this.dialog_.style.zIndex = "";

    // This won't match the native <dialog> exactly because if the user set top on a centered
    // polyfill dialog, that top gets thrown away when the dialog is closed. Not sure it's
    // possible to polyfill this perfectly.
    if (this.replacedStyleTop_) {
      this.dialog_.style.top = "";
      this.replacedStyleTop_ = false;
    }

    // Clear the backdrop and remove from the manager.
    this.backdrop_.parentNode &&
      this.backdrop_.parentNode.removeChild(this.backdrop_);
    dialogPolyfill.dm.removeDialog(this);
  },

  /**
   * @param {boolean} value whether to open or close this dialog
   */
  setOpen: function (value) {
    if (value) {
      this.dialog_.hasAttribute("open") ||
        this.dialog_.setAttribute("open", "");
    } else {
      this.dialog_.removeAttribute("open");
      this.maybeHideModal(); // nb. redundant with MutationObserver
    }
  },

  /**
   * Handles mouse events ('mouseup', 'mousedown', 'click') on the fake .backdrop element, redirecting them as if
   * they were on the dialog itself.
   *
   * @param {!Event} e to redirect
   */
  backdropMouseEvent_: function (e) {
    if (!this.dialog_.hasAttribute("tabindex")) {
      // Clicking on the backdrop should move the implicit cursor, even if dialog cannot be
      // focused. Create a fake thing to focus on. If the backdrop was _before_ the dialog, this
      // would not be needed - clicks would move the implicit cursor there.
      var fake = document.createElement("div");
      this.dialog_.insertBefore(fake, this.dialog_.firstChild);
      fake.tabIndex = -1;
      fake.focus();
      this.dialog_.removeChild(fake);
    } else {
      this.dialog_.focus();
    }

    var redirectedEvent = document.createEvent("MouseEvents");
    redirectedEvent.initMouseEvent(
      e.type,
      e.bubbles,
      e.cancelable,
      window,
      e.detail,
      e.screenX,
      e.screenY,
      e.clientX,
      e.clientY,
      e.ctrlKey,
      e.altKey,
      e.shiftKey,
      e.metaKey,
      e.button,
      e.relatedTarget,
    );
    this.dialog_.dispatchEvent(redirectedEvent);
    e.stopPropagation();
  },

  /**
   * Focuses on the first focusable element within the dialog. This will always blur the current
   * focus, even if nothing within the dialog is found.
   */
  focus_: function () {
    // Find element with `autofocus` attribute, or fall back to the first form/tabindex control.
    var target = this.dialog_.querySelector("[autofocus]:not([disabled])");
    if (!target && this.dialog_.tabIndex >= 0) {
      target = this.dialog_;
    }
    if (!target) {
      target = findFocusableElementWithin(this.dialog_);
    }
    safeBlur(document.activeElement);
    target && target.focus();
  },

  /**
   * Sets the zIndex for the backdrop and dialog.
   *
   * @param {number} dialogZ
   * @param {number} backdropZ
   */
  updateZIndex: function (dialogZ, backdropZ) {
    if (dialogZ < backdropZ) {
      throw new Error("dialogZ should never be < backdropZ");
    }
    this.dialog_.style.zIndex = dialogZ;
    this.backdrop_.style.zIndex = backdropZ;
  },

  /**
   * Shows the dialog. If the dialog is already open, this does nothing.
   */
  show: function () {
    if (!this.dialog_.open) {
      this.setOpen(true);
      this.focus_();
    }
  },

  /**
   * Show this dialog modally.
   */
  showModal: function () {
    if (this.dialog_.hasAttribute("open")) {
      throw new Error(
        "Failed to execute 'showModal' on dialog: The element is already open, and therefore cannot be opened modally.",
      );
    }
    if (!isConnected(this.dialog_)) {
      throw new Error(
        "Failed to execute 'showModal' on dialog: The element is not in a Document.",
      );
    }
    if (!dialogPolyfill.dm.pushDialog(this)) {
      throw new Error(
        "Failed to execute 'showModal' on dialog: There are too many open modal dialogs.",
      );
    }

    this.setOpen(true);
    this.openAsModal_ = true;

    // Optionally center vertically, relative to the current viewport.
    if (dialogPolyfill.needsCentering(this.dialog_)) {
      dialogPolyfill.reposition(this.dialog_);
      this.replacedStyleTop_ = true;
    } else {
      this.replacedStyleTop_ = false;
    }

    // Insert backdrop.
    this.dialog_.parentNode.insertBefore(
      this.backdrop_,
      this.dialog_.nextSibling,
    );

    // Focus on whatever inside the dialog.
    this.focus_();
  },

  /**
   * Closes this HTMLDialogElement. This is optional vs clearing the open
   * attribute, however this fires a 'close' event.
   *
   * @param {string=} opt_returnValue to use as the returnValue
   */
  close: function (opt_returnValue) {
    if (!this.dialog_.hasAttribute("open")) {
      throw new Error(
        "Failed to execute 'close' on dialog: The element does not have an 'open' attribute, and therefore cannot be closed.",
      );
    }
    this.setOpen(false);

    // Leave returnValue untouched in case it was set directly on the element
    if (opt_returnValue !== undefined) {
      this.dialog_.returnValue = opt_returnValue;
    }

    // Triggering "close" event for any attached listeners on the <dialog>.
    var closeEvent = new window.CustomEvent("close", {
      bubbles: false,
      cancelable: false,
    });
    safeDispatchEvent(this.dialog_, closeEvent);
  },
};

var dialogPolyfill = {};

dialogPolyfill.reposition = function (element) {
  var scrollTop = document.body.scrollTop || document.documentElement.scrollTop;
  var topValue = scrollTop + (window.innerHeight - element.offsetHeight) / 2;
  element.style.top = Math.max(scrollTop, topValue) + "px";
};

dialogPolyfill.isInlinePositionSetByStylesheet = function (element) {
  for (var i = 0; i < document.styleSheets.length; ++i) {
    var styleSheet = document.styleSheets[i];
    var cssRules = null;
    // Some browsers throw on cssRules.
    try {
      cssRules = styleSheet.cssRules;
    } catch {
      /* empty */
    }
    if (!cssRules) {
      continue;
    }
    for (var j = 0; j < cssRules.length; ++j) {
      var rule = cssRules[j];
      var selectedNodes = null;
      // Ignore errors on invalid selector texts.
      try {
        selectedNodes = document.querySelectorAll(rule.selectorText);
      } catch {
        /* empty */
      }
      if (!selectedNodes || !inNodeList(selectedNodes, element)) {
        continue;
      }
      var cssTop = rule.style.getPropertyValue("top");
      var cssBottom = rule.style.getPropertyValue("bottom");
      if (
        (cssTop && cssTop !== "auto") ||
        (cssBottom && cssBottom !== "auto")
      ) {
        return true;
      }
    }
  }
  return false;
};

dialogPolyfill.needsCentering = function (dialog) {
  var computedStyle = window.getComputedStyle(dialog);
  if (computedStyle.position !== "absolute") {
    return false;
  }

  // We must determine whether the top/bottom specified value is non-auto.  In
  // WebKit/Blink, checking computedStyle.top == 'auto' is sufficient, but
  // Firefox returns the used value. So we do this crazy thing instead: check
  // the inline style and then go through CSS rules.
  if (
    (dialog.style.top !== "auto" && dialog.style.top !== "") ||
    (dialog.style.bottom !== "auto" && dialog.style.bottom !== "")
  ) {
    return false;
  }
  return !dialogPolyfill.isInlinePositionSetByStylesheet(dialog);
};

/**
 * @param {!Element} element to force upgrade
 */
dialogPolyfill.forceRegisterDialog = function (element) {
  if (element.showModal) {
    console.warn(
      "This browser already supports <dialog>, the polyfill " +
        "may not work correctly",
      element,
    );
  }
  if (element.localName !== "dialog") {
    throw new Error("Failed to register dialog: The element is not a dialog.");
  }
  new dialogPolyfillInfo(/** @type {!HTMLDialogElement} */ element);
};

/**
 * @param {!Element} element to upgrade, if necessary
 */
dialogPolyfill.registerDialog = function (element) {
  if (!element.showModal) {
    dialogPolyfill.forceRegisterDialog(element);
  }
};

/**
 * @constructor
 */
dialogPolyfill.DialogManager = function () {
  /** @type {!dialogPolyfillInfo[]} */
  this.pendingDialogStack = [];

  var checkDOM = this.checkDOM_.bind(this);

  // The overlay is used to simulate how a modal dialog blocks the document.
  // The blocking dialog is positioned on top of the overlay, and the rest of
  // the dialogs on the pending dialog stack are positioned below it. In the
  // actual implementation, the modal dialog stacking is controlled by the
  // top layer, where z-index has no effect.
  this.overlay = document.createElement("div");
  this.overlay.className = "_dialog_overlay";
  this.overlay.addEventListener(
    "click",
    function (e) {
      this.forwardTab_ = undefined;
      e.stopPropagation();
      checkDOM([]); // sanity-check DOM
    }.bind(this),
  );

  this.handleKey_ = this.handleKey_.bind(this);
  this.handleFocus_ = this.handleFocus_.bind(this);

  this.zIndexLow_ = 100000;
  this.zIndexHigh_ = 100000 + 150;

  this.forwardTab_ = undefined;

  if ("MutationObserver" in window) {
    this.mo_ = new MutationObserver(function (records) {
      var removed = [];
      records.forEach(function (rec) {
        for (var i = 0, c; (c = rec.removedNodes[i]); ++i) {
          if (!(c instanceof Element)) {
            continue;
          }

          if (c.localName === "dialog") {
            removed.push(c);
          }

          removed = removed.concat(c.querySelectorAll("dialog"));
        }
      });
      removed.length && checkDOM(removed);
    });
  }
};

/**
 * Called on the first modal dialog being shown. Adds the overlay and related
 * handlers.
 */
dialogPolyfill.DialogManager.prototype.blockDocument = function () {
  document.documentElement.addEventListener("focus", this.handleFocus_, true);
  document.addEventListener("keydown", this.handleKey_);
  this.mo_ && this.mo_.observe(document, { childList: true, subtree: true });
};

/**
 * Called on the first modal dialog being removed, i.e., when no more modal
 * dialogs are visible.
 */
dialogPolyfill.DialogManager.prototype.unblockDocument = function () {
  document.documentElement.removeEventListener(
    "focus",
    this.handleFocus_,
    true,
  );
  document.removeEventListener("keydown", this.handleKey_);
  this.mo_ && this.mo_.disconnect();
};

/**
 * Updates the stacking of all known dialogs.
 */
dialogPolyfill.DialogManager.prototype.updateStacking = function () {
  var zIndex = this.zIndexHigh_;

  for (var i = 0, dpi; (dpi = this.pendingDialogStack[i]); ++i) {
    dpi.updateZIndex(--zIndex, --zIndex);
    if (i === 0) {
      this.overlay.style.zIndex = --zIndex;
    }
  }

  // Make the overlay a sibling of the dialog itself.
  var last = this.pendingDialogStack[0];
  if (last) {
    var p = last.dialog.parentNode || document.body;
    p.appendChild(this.overlay);
  } else if (this.overlay.parentNode) {
    this.overlay.parentNode.removeChild(this.overlay);
  }
};

/**
 * @param {Element} candidate to check if contained or is the top-most modal dialog
 * @return {boolean} whether candidate is contained in top dialog
 */
dialogPolyfill.DialogManager.prototype.containedByTopDialog_ = function (
  candidate,
) {
  while ((candidate = findNearestDialog(candidate))) {
    for (var i = 0, dpi; (dpi = this.pendingDialogStack[i]); ++i) {
      if (dpi.dialog === candidate) {
        return i === 0; // only valid if top-most
      }
    }
    candidate = candidate.parentElement;
  }
  return false;
};

dialogPolyfill.DialogManager.prototype.handleFocus_ = function (event) {
  var target = event.composedPath ? event.composedPath()[0] : event.target;

  if (this.containedByTopDialog_(target)) {
    return;
  }

  if (document.activeElement === document.documentElement) {
    return;
  }

  event.preventDefault();
  event.stopPropagation();
  safeBlur(/** @type {Element} */ target);

  if (this.forwardTab_ === undefined) {
    return;
  } // move focus only from a tab key

  var dpi = this.pendingDialogStack[0];
  var dialog = dpi.dialog;
  var position = dialog.compareDocumentPosition(target);
  if (position & Node.DOCUMENT_POSITION_PRECEDING) {
    if (this.forwardTab_) {
      // forward
      dpi.focus_();
    } else if (target !== document.documentElement) {
      // backwards if we're not already focused on <html>
      document.documentElement.focus();
    }
  } else {
    // TODO: Focus after the dialog, is ignored.
  }

  return false;
};

dialogPolyfill.DialogManager.prototype.handleKey_ = function (event) {
  this.forwardTab_ = undefined;
  if (event.keyCode === 27) {
    event.preventDefault();
    event.stopPropagation();
    var cancelEvent = new window.CustomEvent("cancel", {
      bubbles: false,
      cancelable: true,
    });
    var dpi = this.pendingDialogStack[0];
    if (dpi && safeDispatchEvent(dpi.dialog, cancelEvent)) {
      dpi.dialog.close();
    }
  } else if (event.keyCode === 9) {
    this.forwardTab_ = !event.shiftKey;
  }
};

/**
 * Finds and downgrades any known modal dialogs that are no longer displayed. Dialogs that are
 * removed and immediately readded don't stay modal, they become normal.
 *
 * @param {!HTMLDialogElement[]} removed that have definitely been removed
 */
dialogPolyfill.DialogManager.prototype.checkDOM_ = function (removed) {
  // This operates on a clone because it may cause it to change. Each change also calls
  // updateStacking, which only actually needs to happen once. But who removes many modal dialogs
  // at a time?!
  var clone = this.pendingDialogStack.slice();
  clone.forEach(function (dpi) {
    if (removed.indexOf(dpi.dialog) !== -1) {
      dpi.downgradeModal();
    } else {
      dpi.maybeHideModal();
    }
  });
};

/**
 * @param {!dialogPolyfillInfo} dpi
 * @return {boolean} whether the dialog was allowed
 */
dialogPolyfill.DialogManager.prototype.pushDialog = function (dpi) {
  var allowed = (this.zIndexHigh_ - this.zIndexLow_) / 2 - 1;
  if (this.pendingDialogStack.length >= allowed) {
    return false;
  }
  if (this.pendingDialogStack.unshift(dpi) === 1) {
    this.blockDocument();
  }
  this.updateStacking();
  return true;
};

/**
 * @param {!dialogPolyfillInfo} dpi
 */
dialogPolyfill.DialogManager.prototype.removeDialog = function (dpi) {
  var index = this.pendingDialogStack.indexOf(dpi);
  if (index === -1) {
    return;
  }

  this.pendingDialogStack.splice(index, 1);
  if (this.pendingDialogStack.length === 0) {
    this.unblockDocument();
  }
  this.updateStacking();
};

if (needPolyfill) {
  dialogPolyfill.dm = new dialogPolyfill.DialogManager();
  dialogPolyfill.formSubmitter = null;
  dialogPolyfill.imagemapUseValue = null;
}

/**
 * Installs global handlers, such as click listers and native method overrides. These are needed
 * even if a no dialog is registered, as they deal with <form method="dialog">.
 */
if (needPolyfill) {
  /**
   * If HTMLFormElement translates method="DIALOG" into 'get', then replace the descriptor with
   * one that returns the correct value.
   */
  var testForm = document.createElement("form");
  testForm.setAttribute("method", "dialog");
  if (testForm.method !== "dialog") {
    var methodDescriptor = Object.getOwnPropertyDescriptor(
      HTMLFormElement.prototype,
      "method",
    );
    if (methodDescriptor) {
      // nb. Some older iOS and older PhantomJS fail to return the descriptor. Don't do anything
      // and don't bother to update the element.
      var realGet = methodDescriptor.get;
      methodDescriptor.get = function () {
        if (isFormMethodDialog(this)) {
          return "dialog";
        }
        return realGet.call(this);
      };
      var realSet = methodDescriptor.set;
      /** @this {HTMLElement} */
      methodDescriptor.set = function (v) {
        if (typeof v === "string" && v.toLowerCase() === "dialog") {
          return this.setAttribute("method", v);
        }
        return realSet.call(this, v);
      };
      Object.defineProperty(
        HTMLFormElement.prototype,
        "method",
        methodDescriptor,
      );
    }
  }

  /**
   * Global 'click' handler, to capture the <input type="submit"> or <button> element which has
   * submitted a <form method="dialog">. Needed as Safari and others don't report this inside
   * document.activeElement.
   */
  document.addEventListener(
    "click",
    function (ev) {
      dialogPolyfill.formSubmitter = null;
      dialogPolyfill.imagemapUseValue = null;
      if (ev.defaultPrevented) {
        return;
      } // e.g. a submit which prevents default submission

      var target = /** @type {Element} */ ev.target;
      if ("composedPath" in ev) {
        var path = ev.composedPath();
        target = path.shift() || target;
      }
      if (!target || !isFormMethodDialog(target.form)) {
        return;
      }

      var valid =
        target.type === "submit" &&
        ["button", "input"].indexOf(target.localName) > -1;
      if (!valid) {
        if (!(target.localName === "input" && target.type === "image")) {
          return;
        }
        // this is a <input type="image">, which can submit forms
        dialogPolyfill.imagemapUseValue = ev.offsetX + "," + ev.offsetY;
      }

      var dialog = findNearestDialog(target);
      if (!dialog) {
        return;
      }

      dialogPolyfill.formSubmitter = target;
    },
    false,
  );

  /**
   * Global 'submit' handler. This handles submits of `method="dialog"` which are invalid, i.e.,
   * outside a dialog. They get prevented.
   */
  document.addEventListener("submit", function (ev) {
    var form = ev.target;
    var dialog = findNearestDialog(form);
    if (dialog) {
      return; // ignore, handle there
    }

    var submitter = findFormSubmitter(ev);
    var formmethod =
      (submitter && submitter.getAttribute("formmethod")) ||
      form.getAttribute("method");
    if (formmethod === "dialog") {
      ev.preventDefault();
    }
  });

  /**
   * Replace the native HTMLFormElement.submit() method, as it won't fire the
   * submit event and give us a chance to respond.
   */
  var nativeFormSubmit = HTMLFormElement.prototype.submit;
  var replacementFormSubmit = function () {
    if (!isFormMethodDialog(this)) {
      return nativeFormSubmit.call(this);
    }
    var dialog = findNearestDialog(this);
    dialog && dialog.close();
  };
  HTMLFormElement.prototype.submit = replacementFormSubmit;
}

export default dialogPolyfill as {
  registerDialog(dialog: HTMLDialogElement): void;
  forceRegisterDialog(dialog: HTMLDialogElement): void;
};