/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
 *           (C) 2001 Dirk Mueller (mueller@kde.org)
 * Copyright (C) 2004-2016 Apple Inc. All rights reserved.
 *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
 *
 * 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 "FormAssociatedElement.h"

#include "EditorClient.h"
#include "FormController.h"
#include "Frame.h"
#include "HTMLFormControlElement.h"
#include "HTMLFormElement.h"
#include "HTMLNames.h"
#include "HTMLObjectElement.h"
#include "IdTargetObserver.h"

namespace WebCore {

using namespace HTMLNames;

class FormAttributeTargetObserver final : private IdTargetObserver {
    WTF_MAKE_FAST_ALLOCATED;
public:
    FormAttributeTargetObserver(const AtomicString& id, FormAssociatedElement&);

private:
    virtual void idTargetChanged() override;

    FormAssociatedElement& m_element;
};

FormAssociatedElement::FormAssociatedElement(HTMLFormElement* form)
    : m_form(nullptr)
    , m_formSetByParser(form)
{
}

FormAssociatedElement::~FormAssociatedElement()
{
    setForm(nullptr);
}

void FormAssociatedElement::didMoveToNewDocument(Document* oldDocument)
{
    HTMLElement& element = asHTMLElement();
    if (oldDocument && element.fastHasAttribute(formAttr))
        resetFormAttributeTargetObserver();
}

void FormAssociatedElement::insertedInto(ContainerNode& insertionPoint)
{
    HTMLElement& element = asHTMLElement();
    if (m_formSetByParser) {
        setForm(m_formSetByParser);
        m_formSetByParser = nullptr;
    }

    if (m_form && element.rootElement() != m_form->rootElement())
        setForm(nullptr);

    if (!insertionPoint.inDocument())
        return;

    if (element.fastHasAttribute(formAttr))
        resetFormAttributeTargetObserver();
}

void FormAssociatedElement::removedFrom(ContainerNode& insertionPoint)
{
    HTMLElement& element = asHTMLElement();
    if (insertionPoint.inDocument() && element.fastHasAttribute(formAttr))
        m_formAttributeTargetObserver = nullptr;
    // If the form and element are both in the same tree, preserve the connection to the form.
    // Otherwise, null out our form and remove ourselves from the form's list of elements.
    if (m_form && element.highestAncestor() != m_form->highestAncestor())
        setForm(nullptr);
}

HTMLFormElement* FormAssociatedElement::findAssociatedForm(const HTMLElement* element, HTMLFormElement* currentAssociatedForm)
{
    const AtomicString& formId(element->fastGetAttribute(formAttr));
    if (!formId.isNull() && element->inDocument()) {
        // The HTML5 spec says that the element should be associated with
        // the first element in the document to have an ID that equal to
        // the value of form attribute, so we put the result of
        // treeScope().getElementById() over the given element.
        HTMLFormElement* newForm = nullptr;
        Element* newFormCandidate = element->treeScope().getElementById(formId);
        if (is<HTMLFormElement>(newFormCandidate))
            newForm = downcast<HTMLFormElement>(newFormCandidate);
        return newForm;
    }

    if (!currentAssociatedForm)
        return HTMLFormElement::findClosestFormAncestor(*element);

    return currentAssociatedForm;
}

void FormAssociatedElement::formRemovedFromTree(const Node* formRoot)
{
    ASSERT(m_form);
    if (asHTMLElement().highestAncestor() != formRoot)
        setForm(nullptr);
}

void FormAssociatedElement::setForm(HTMLFormElement* newForm)
{
    if (m_form == newForm)
        return;
    willChangeForm();
    if (m_form)
        m_form->removeFormElement(this);
    m_form = newForm;
    if (m_form)
        m_form->registerFormElement(this);
    didChangeForm();
}

void FormAssociatedElement::willChangeForm()
{
}

void FormAssociatedElement::didChangeForm()
{
}

void FormAssociatedElement::formWillBeDestroyed()
{
    ASSERT(m_form);
    if (!m_form)
        return;
    willChangeForm();
    m_form = nullptr;
    didChangeForm();
}

void FormAssociatedElement::resetFormOwner()
{
    HTMLFormElement* originalForm = m_form;
    setForm(findAssociatedForm(&asHTMLElement(), m_form));
    HTMLElement& element = asHTMLElement();
    if (m_form && m_form != originalForm && m_form->inDocument())
        element.document().didAssociateFormControl(&element);
}

void FormAssociatedElement::formAttributeChanged()
{
    HTMLElement& element = asHTMLElement();
    if (!element.fastHasAttribute(formAttr)) {
        // The form attribute removed. We need to reset form owner here.
        HTMLFormElement* originalForm = m_form;
        setForm(HTMLFormElement::findClosestFormAncestor(element));
        if (m_form && m_form != originalForm && m_form->inDocument())
            element.document().didAssociateFormControl(&element);
        m_formAttributeTargetObserver = nullptr;
    } else {
        resetFormOwner();
        if (element.inDocument())
            resetFormAttributeTargetObserver();
    }
}

bool FormAssociatedElement::customError() const
{
    return willValidate() && !m_customValidationMessage.isEmpty();
}

bool FormAssociatedElement::hasBadInput() const
{
    return false;
}

bool FormAssociatedElement::patternMismatch() const
{
    return false;
}

bool FormAssociatedElement::rangeOverflow() const
{
    return false;
}

bool FormAssociatedElement::rangeUnderflow() const
{
    return false;
}

bool FormAssociatedElement::stepMismatch() const
{
    return false;
}

bool FormAssociatedElement::tooLong() const
{
    return false;
}

bool FormAssociatedElement::typeMismatch() const
{
    return false;
}

bool FormAssociatedElement::valid() const
{
    bool someError = typeMismatch() || stepMismatch() || rangeUnderflow() || rangeOverflow()
        || tooLong() || patternMismatch() || valueMissing() || hasBadInput() || customError();
    return !someError;
}

bool FormAssociatedElement::valueMissing() const
{
    return false;
}

String FormAssociatedElement::customValidationMessage() const
{
    return m_customValidationMessage;
}

String FormAssociatedElement::validationMessage() const
{
    return customError() ? m_customValidationMessage : String();
}

void FormAssociatedElement::setCustomValidity(const String& error)
{
    m_customValidationMessage = error;
}

void FormAssociatedElement::resetFormAttributeTargetObserver()
{
    m_formAttributeTargetObserver = std::make_unique<FormAttributeTargetObserver>(asHTMLElement().fastGetAttribute(formAttr), *this);
}

void FormAssociatedElement::formAttributeTargetChanged()
{
    resetFormOwner();
}

const AtomicString& FormAssociatedElement::name() const
{
    const AtomicString& name = asHTMLElement().getNameAttribute();
    return name.isNull() ? emptyAtom : name;
}

bool FormAssociatedElement::isFormControlElementWithState() const
{
    return false;
}

FormAttributeTargetObserver::FormAttributeTargetObserver(const AtomicString& id, FormAssociatedElement& element)
    : IdTargetObserver(element.asHTMLElement().treeScope().idTargetObserverRegistry(), id)
    , m_element(element)
{
}

void FormAttributeTargetObserver::idTargetChanged()
{
    m_element.formAttributeTargetChanged();
}

} // namespace Webcore