/*
 * Copyright (C) 2005-2018 Apple Inc. All rights reserved.
 * Copyright (C) 2010 Google Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#include "config.h"
#include "RadioInputType.h"

#include "Frame.h"
#include "HTMLFormElement.h"
#include "HTMLInputElement.h"
#include "HTMLNames.h"
#include "InputTypeNames.h"
#include "KeyboardEvent.h"
#include "LocalizedStrings.h"
#include "MouseEvent.h"
#include "NodeTraversal.h"
#include "SpatialNavigation.h"

namespace WebCore {

using namespace HTMLNames;

const AtomString& RadioInputType::formControlType() const
{
    return InputTypeNames::radio();
}

bool RadioInputType::valueMissing(const String&) const
{
    ASSERT(element());
    return element()->isInRequiredRadioButtonGroup() && !element()->checkedRadioButtonForGroup();
}

String RadioInputType::valueMissingText() const
{
    return validationMessageValueMissingForRadioText();
}

void RadioInputType::handleClickEvent(MouseEvent& event)
{
    event.setDefaultHandled();
}

auto RadioInputType::handleKeydownEvent(KeyboardEvent& event) -> ShouldCallBaseEventHandler
{
    if (BaseCheckableInputType::handleKeydownEvent(event) == ShouldCallBaseEventHandler::No)
        return ShouldCallBaseEventHandler::No;
    if (event.defaultHandled())
        return ShouldCallBaseEventHandler::Yes;
    const String& key = event.keyIdentifier();
    if (key != "Up" && key != "Down" && key != "Left" && key != "Right")
        return ShouldCallBaseEventHandler::Yes;

    ASSERT(element());
    // Left and up mean "previous radio button".
    // Right and down mean "next radio button".
    // Tested in WinIE, and even for RTL, left still means previous radio button (and so moves
    // to the right).  Seems strange, but we'll match it.
    // However, when using Spatial Navigation, we need to be able to navigate without changing the selection.
    if (isSpatialNavigationEnabled(element()->document().frame()))
        return ShouldCallBaseEventHandler::Yes;
    bool forward = (key == "Down" || key == "Right");

    // We can only stay within the form's children if the form hasn't been demoted to a leaf because
    // of malformed HTML.
    RefPtr<Node> node = element();
    while ((node = (forward ? NodeTraversal::next(*node) : NodeTraversal::previous(*node)))) {
        // Once we encounter a form element, we know we're through.
        if (is<HTMLFormElement>(*node))
            break;
        // Look for more radio buttons.
        if (!is<HTMLInputElement>(*node))
            continue;
        RefPtr<HTMLInputElement> inputElement = downcast<HTMLInputElement>(node.get());
        if (inputElement->form() != element()->form())
            break;
        if (inputElement->isRadioButton() && inputElement->name() == element()->name() && inputElement->isFocusable()) {
            element()->document().setFocusedElement(inputElement.get());
            inputElement->dispatchSimulatedClick(&event, SendNoEvents, DoNotShowPressedLook);
            event.setDefaultHandled();
            return ShouldCallBaseEventHandler::Yes;
        }
    }
    return ShouldCallBaseEventHandler::Yes;
}

void RadioInputType::handleKeyupEvent(KeyboardEvent& event)
{
    const String& key = event.keyIdentifier();
    if (key != "U+0020")
        return;

    ASSERT(element());
    // If an unselected radio is tabbed into (because the entire group has nothing
    // checked, or because of some explicit .focus() call), then allow space to check it.
    if (element()->checked())
        return;
    dispatchSimulatedClickIfActive(event);
}

bool RadioInputType::isKeyboardFocusable(KeyboardEvent* event) const
{
    if (!InputType::isKeyboardFocusable(event))
        return false;

    ASSERT(element());
    // When using Spatial Navigation, every radio button should be focusable.
    if (isSpatialNavigationEnabled(element()->document().frame()))
        return true;

    // Never allow keyboard tabbing to leave you in the same radio group.  Always
    // skip any other elements in the group.
    RefPtr<Element> currentFocusedNode = element()->document().focusedElement();
    if (is<HTMLInputElement>(currentFocusedNode)) {
        HTMLInputElement& focusedInput = downcast<HTMLInputElement>(*currentFocusedNode);
        if (focusedInput.isRadioButton() && focusedInput.form() == element()->form() && focusedInput.name() == element()->name())
            return false;
    }

    // Allow keyboard focus if we're checked or if nothing in the group is checked.
    return element()->checked() || !element()->checkedRadioButtonForGroup();
}

bool RadioInputType::shouldSendChangeEventAfterCheckedChanged()
{
    // Don't send a change event for a radio button that's getting unchecked.
    // This was done to match the behavior of other browsers.
    ASSERT(element());
    return element()->checked();
}

void RadioInputType::willDispatchClick(InputElementClickState& state)
{
    ASSERT(element());
    // An event handler can use preventDefault or "return false" to reverse the selection we do here.
    // The InputElementClickState object contains what we need to undo what we did here in didDispatchClick.

    // We want radio groups to end up in sane states, i.e., to have something checked.
    // Therefore if nothing is currently selected, we won't allow the upcoming action to be "undone", since
    // we want some object in the radio group to actually get selected.

    state.checked = element()->checked();
    state.checkedRadioButton = element()->checkedRadioButtonForGroup();

    element()->setChecked(true);
}

void RadioInputType::didDispatchClick(Event& event, const InputElementClickState& state)
{
    if (event.defaultPrevented() || event.defaultHandled()) {
        // Restore the original selected radio button if possible.
        // Make sure it is still a radio button and only do the restoration if it still belongs to our group.
        auto& button = state.checkedRadioButton;
        ASSERT(element());
        if (button && button->isRadioButton() && button->form() == element()->form() && button->name() == element()->name())
            button->setChecked(true);
        else
            element()->setChecked(false);
    } else if (state.checked != element()->checked())
        fireInputAndChangeEvents();

    // The work we did in willDispatchClick was default handling.
    event.setDefaultHandled();
}

bool RadioInputType::matchesIndeterminatePseudoClass() const
{
    ASSERT(element());
    auto& element = *this->element();
    if (auto* radioButtonGroups = element.radioButtonGroups())
        return !radioButtonGroups->hasCheckedButton(element);
    return !element.checked();
}

} // namespace WebCore