/*
 * Copyright (C) 2012 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  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.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS 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 APPLE OR ITS 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.
 */

#include "third_party/blink/renderer/core/html/html_dialog_element.h"

#include "third_party/blink/renderer/core/accessibility/ax_object_cache.h"
#include "third_party/blink/renderer/core/dom/events/event.h"
#include "third_party/blink/renderer/core/dom/flat_tree_traversal.h"
#include "third_party/blink/renderer/core/execution_context/execution_context.h"
#include "third_party/blink/renderer/core/frame/local_frame.h"
#include "third_party/blink/renderer/core/frame/local_frame_view.h"
#include "third_party/blink/renderer/core/frame/web_feature.h"
#include "third_party/blink/renderer/core/fullscreen/fullscreen.h"
#include "third_party/blink/renderer/core/html/forms/html_form_control_element.h"
#include "third_party/blink/renderer/core/html/html_frame_owner_element.h"
#include "third_party/blink/renderer/platform/bindings/exception_state.h"
#include "third_party/blink/renderer/platform/instrumentation/use_counter.h"

namespace blink {

// https://html.spec.whatwg.org/C/#the-dialog-element
// This function chooses the focused element when show() or showModal() is
// invoked, as described in their spec.
static void SetFocusForDialog(HTMLDialogElement* dialog) {
  Element* control = nullptr;
  Node* next = nullptr;

  // TODO(kochi): How to find focusable element inside Shadow DOM is not
  // currently specified.  This may change at any time.
  // See crbug/383230 and https://github.com/whatwg/html/issues/2393 .
  for (Node* node = FlatTreeTraversal::FirstChild(*dialog); node; node = next) {
    next = IsA<HTMLDialogElement>(*node)
               ? FlatTreeTraversal::NextSkippingChildren(*node, dialog)
               : FlatTreeTraversal::Next(*node, dialog);

    auto* element = DynamicTo<Element>(node);
    if (!element)
      continue;
    if (element->IsAutofocusable() && element->IsFocusable()) {
      control = element;
      break;
    }
    if (!control && element->IsFocusable())
      control = element;
  }
  if (!control)
    control = dialog;

  // 3. Run the focusing steps for control.
  if (control->IsFocusable())
    control->focus();
  else
    dialog->GetDocument().ClearFocusedElement();

  // 4. Let topDocument be the active document of control's node document's
  // browsing context's top-level browsing context.
  // 5. If control's node document's origin is not the same as the origin of
  // topDocument, then return.
  Document& doc = control->GetDocument();
  if (!doc.IsActive())
    return;
  if (!doc.IsInMainFrame() &&
      !doc.TopFrameOrigin()->CanAccess(
          doc.GetExecutionContext()->GetSecurityOrigin())) {
    return;
  }

  // 6. Empty topDocument's autofocus candidates.
  // 7. Set topDocument's autofocus processed flag to true.
  doc.TopDocument().FinalizeAutofocus();
}

static void InertSubtreesChanged(Document& document) {
  // SetIsInert recurses through subframes to propagate the inert bit.
  if (document.GetFrame()) {
    document.GetFrame()->SetIsInert(document.LocalOwner() &&
                                    document.LocalOwner()->IsInert());
  }

  // When a modal dialog opens or closes, nodes all over the accessibility
  // tree can change inertness which means they must be added or removed from
  // the tree. The most foolproof way is to clear the entire tree and rebuild
  // it, though a more clever way is probably possible.
  document.ClearAXObjectCache();
}

HTMLDialogElement::HTMLDialogElement(Document& document)
    : HTMLElement(html_names::kDialogTag, document),
      is_modal_(false),
      return_value_("") {
  UseCounter::Count(document, WebFeature::kDialogElement);
}

void HTMLDialogElement::close(const String& return_value) {
  // https://html.spec.whatwg.org/C/#close-the-dialog

  if (!FastHasAttribute(html_names::kOpenAttr))
    return;
  SetBooleanAttribute(html_names::kOpenAttr, false);
  SetIsModal(false);

  HTMLDialogElement* active_modal_dialog = GetDocument().ActiveModalDialog();
  GetDocument().RemoveFromTopLayer(this);
  if (active_modal_dialog == this)
    InertSubtreesChanged(GetDocument());

  if (!return_value.IsNull())
    return_value_ = return_value;

  ScheduleCloseEvent();
}

void HTMLDialogElement::SetIsModal(bool is_modal) {
  if (is_modal != is_modal_)
    PseudoStateChanged(CSSSelector::kPseudoModal);
  is_modal_ = is_modal;
}

void HTMLDialogElement::ScheduleCloseEvent() {
  Event* event = Event::Create(event_type_names::kClose);
  event->SetTarget(this);
  GetDocument().EnqueueAnimationFrameEvent(event);
}

void HTMLDialogElement::show() {
  if (FastHasAttribute(html_names::kOpenAttr))
    return;
  SetBooleanAttribute(html_names::kOpenAttr, true);

  // Showing a <dialog> should hide all open popups.
  GetDocument().HideAllPopupsUntil(nullptr);

  // The layout must be updated here because setFocusForDialog calls
  // Element::isFocusable, which requires an up-to-date layout.
  GetDocument().UpdateStyleAndLayout(DocumentUpdateReason::kJavaScript);

  SetFocusForDialog(this);
}

void HTMLDialogElement::showModal(ExceptionState& exception_state) {
  if (FastHasAttribute(html_names::kOpenAttr)) {
    exception_state.ThrowDOMException(DOMExceptionCode::kInvalidStateError,
                                      "The element already has an 'open' "
                                      "attribute, and therefore cannot be "
                                      "opened modally.");
    return;
  }
  if (!isConnected()) {
    exception_state.ThrowDOMException(DOMExceptionCode::kInvalidStateError,
                                      "The element is not in a Document.");
    return;
  }

  // See comment in |Fullscreen::RequestFullscreen|.
  if (Fullscreen::IsInFullscreenElementStack(*this)) {
    UseCounter::Count(GetDocument(),
                      WebFeature::kShowModalForElementInFullscreenStack);
  }

  // Showing a <dialog> should hide all open popups.
  GetDocument().HideAllPopupsUntil(nullptr);

  GetDocument().AddToTopLayer(this);
  SetBooleanAttribute(html_names::kOpenAttr, true);

  SetIsModal(true);
  GetDocument().UpdateStyleAndLayout(DocumentUpdateReason::kJavaScript);

  // Throw away the AX cache first, so the subsequent steps don't have a chance
  // of queuing up AX events on objects that would be invalidated when the cache
  // is thrown away.
  InertSubtreesChanged(GetDocument());

  SetFocusForDialog(this);
}

void HTMLDialogElement::RemovedFrom(ContainerNode& insertion_point) {
  HTMLElement::RemovedFrom(insertion_point);
  InertSubtreesChanged(GetDocument());
}

void HTMLDialogElement::DefaultEventHandler(Event& event) {
  if (event.type() == event_type_names::kCancel) {
    close();
    event.SetDefaultHandled();
    return;
  }
  HTMLElement::DefaultEventHandler(event);
}

}  // namespace blink