/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
 *           (C) 2001 Dirk Mueller (mueller@kde.org)
 *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
 * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
 * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
 * Copyright (C) 2013 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 "core/dom/FullscreenElementStack.h"

#include "HTMLNames.h"
#include "core/dom/Document.h"
#include "core/dom/Element.h"
#include "core/events/Event.h"
#include "core/html/HTMLFrameOwnerElement.h"
#include "core/page/Chrome.h"
#include "core/page/ChromeClient.h"
#include "core/frame/Frame.h"
#include "core/page/Page.h"
#include "core/page/Settings.h"
#include "core/rendering/RenderFullScreen.h"
#include "platform/UserGestureIndicator.h"

namespace WebCore {

using namespace HTMLNames;

static bool isAttributeOnAllOwners(const WebCore::QualifiedName& attribute, const WebCore::QualifiedName& prefixedAttribute, const HTMLFrameOwnerElement* owner)
{
    if (!owner)
        return true;
    do {
        if (!(owner->hasAttribute(attribute) || owner->hasAttribute(prefixedAttribute)))
            return false;
    } while ((owner = owner->document().ownerElement()));
    return true;
}

const char* FullscreenElementStack::supplementName()
{
    return "FullscreenElementStack";
}

FullscreenElementStack* FullscreenElementStack::from(Document* document)
{
    FullscreenElementStack* fullscreen = fromIfExists(document);
    if (!fullscreen) {
        fullscreen = new FullscreenElementStack(document);
        DocumentSupplement::provideTo(document, supplementName(), adoptPtr(fullscreen));
    }

    return fullscreen;
}

FullscreenElementStack* FullscreenElementStack::fromIfExistsSlow(Document* document)
{
    return static_cast<FullscreenElementStack*>(DocumentSupplement::from(document, supplementName()));
}

Element* FullscreenElementStack::fullscreenElementFrom(Document* document)
{
    if (FullscreenElementStack* found = fromIfExists(document))
        return found->webkitFullscreenElement();
    return 0;
}

Element* FullscreenElementStack::currentFullScreenElementFrom(Document* document)
{
    if (FullscreenElementStack* found = fromIfExists(document))
        return found->webkitCurrentFullScreenElement();
    return 0;
}

bool FullscreenElementStack::isFullScreen(Document* document)
{
    if (FullscreenElementStack* found = fromIfExists(document))
        return found->webkitIsFullScreen();
    return false;
}

FullscreenElementStack::FullscreenElementStack(Document* document)
    : DocumentLifecycleObserver(document)
    , m_areKeysEnabledInFullScreen(false)
    , m_fullScreenRenderer(0)
    , m_fullScreenChangeDelayTimer(this, &FullscreenElementStack::fullScreenChangeDelayTimerFired)
{
    document->setHasFullscreenElementStack();
}

FullscreenElementStack::~FullscreenElementStack()
{
}

inline Document* FullscreenElementStack::document()
{
    return lifecycleContext();
}

void FullscreenElementStack::documentWasDetached()
{
    m_fullScreenChangeEventTargetQueue.clear();
    m_fullScreenErrorEventTargetQueue.clear();

    if (m_fullScreenRenderer)
        setFullScreenRenderer(0);
}

void FullscreenElementStack::documentWasDisposed()
{
    m_fullScreenElement = 0;
    m_fullScreenElementStack.clear();
}

bool FullscreenElementStack::fullScreenIsAllowedForElement(Element* element) const
{
    ASSERT(element);
    return isAttributeOnAllOwners(allowfullscreenAttr, webkitallowfullscreenAttr, element->document().ownerElement());
}

void FullscreenElementStack::requestFullScreenForElement(Element* element, unsigned short flags, FullScreenCheckType checkType)
{
    // The Mozilla Full Screen API <https://wiki.mozilla.org/Gecko:FullScreenAPI> has different requirements
    // for full screen mode, and do not have the concept of a full screen element stack.
    bool inLegacyMozillaMode = (flags & Element::LEGACY_MOZILLA_REQUEST);

    do {
        if (!element)
            element = document()->documentElement();

        // 1. If any of the following conditions are true, terminate these steps and queue a task to fire
        // an event named fullscreenerror with its bubbles attribute set to true on the context object's
        // node document:

        // The context object is not in a document.
        if (!element->inDocument())
            break;

        // The context object's node document, or an ancestor browsing context's document does not have
        // the fullscreen enabled flag set.
        if (checkType == EnforceIFrameAllowFullScreenRequirement && !fullScreenIsAllowedForElement(element))
            break;

        // The context object's node document fullscreen element stack is not empty and its top element
        // is not an ancestor of the context object. (NOTE: Ignore this requirement if the request was
        // made via the legacy Mozilla-style API.)
        if (!m_fullScreenElementStack.isEmpty() && !inLegacyMozillaMode) {
            Element* lastElementOnStack = m_fullScreenElementStack.last().get();
            if (lastElementOnStack == element || !lastElementOnStack->contains(element))
                break;
        }

        // A descendant browsing context's document has a non-empty fullscreen element stack.
        bool descendentHasNonEmptyStack = false;
        for (Frame* descendant = document()->frame() ? document()->frame()->tree().traverseNext() : 0; descendant; descendant = descendant->tree().traverseNext()) {
            if (fullscreenElementFrom(descendant->document())) {
                descendentHasNonEmptyStack = true;
                break;
            }
        }
        if (descendentHasNonEmptyStack && !inLegacyMozillaMode)
            break;

        // This algorithm is not allowed to show a pop-up:
        //   An algorithm is allowed to show a pop-up if, in the task in which the algorithm is running, either:
        //   - an activation behavior is currently being processed whose click event was trusted, or
        //   - the event listener for a trusted click event is being handled.
        // FIXME: Does this need to null-check settings()?
        if (!UserGestureIndicator::processingUserGesture() && (!element->isMediaElement() || document()->settings()->mediaFullscreenRequiresUserGesture()))
            break;

        // There is a previously-established user preference, security risk, or platform limitation.
        if (!document()->settings() || !document()->settings()->fullScreenEnabled())
            break;

        // 2. Let doc be element's node document. (i.e. "this")
        Document* currentDoc = document();

        // 3. Let docs be all doc's ancestor browsing context's documents (if any) and doc.
        Deque<Document*> docs;

        do {
            docs.prepend(currentDoc);
            currentDoc = currentDoc->ownerElement() ? &currentDoc->ownerElement()->document() : 0;
        } while (currentDoc);

        // 4. For each document in docs, run these substeps:
        Deque<Document*>::iterator current = docs.begin(), following = docs.begin();

        do {
            ++following;

            // 1. Let following document be the document after document in docs, or null if there is no
            // such document.
            Document* currentDoc = *current;
            Document* followingDoc = following != docs.end() ? *following : 0;

            // 2. If following document is null, push context object on document's fullscreen element
            // stack, and queue a task to fire an event named fullscreenchange with its bubbles attribute
            // set to true on the document.
            if (!followingDoc) {
                from(currentDoc)->pushFullscreenElementStack(element);
                addDocumentToFullScreenChangeEventQueue(currentDoc);
                continue;
            }

            // 3. Otherwise, if document's fullscreen element stack is either empty or its top element
            // is not following document's browsing context container,
            Element* topElement = fullscreenElementFrom(currentDoc);
            if (!topElement || topElement != followingDoc->ownerElement()) {
                // ...push following document's browsing context container on document's fullscreen element
                // stack, and queue a task to fire an event named fullscreenchange with its bubbles attribute
                // set to true on document.
                from(currentDoc)->pushFullscreenElementStack(followingDoc->ownerElement());
                addDocumentToFullScreenChangeEventQueue(currentDoc);
                continue;
            }

            // 4. Otherwise, do nothing for this document. It stays the same.
        } while (++current != docs.end());

        // 5. Return, and run the remaining steps asynchronously.
        // 6. Optionally, perform some animation.
        m_areKeysEnabledInFullScreen = flags & Element::ALLOW_KEYBOARD_INPUT;
        document()->page()->chrome().client().enterFullScreenForElement(element);

        // 7. Optionally, display a message indicating how the user can exit displaying the context object fullscreen.
        return;
    } while (0);

    m_fullScreenErrorEventTargetQueue.append(element ? element : document()->documentElement());
    m_fullScreenChangeDelayTimer.startOneShot(0);
}

void FullscreenElementStack::webkitCancelFullScreen()
{
    // The Mozilla "cancelFullScreen()" API behaves like the W3C "fully exit fullscreen" behavior, which
    // is defined as:
    // "To fully exit fullscreen act as if the exitFullscreen() method was invoked on the top-level browsing
    // context's document and subsequently empty that document's fullscreen element stack."
    if (!fullscreenElementFrom(document()->topDocument()))
        return;

    // To achieve that aim, remove all the elements from the top document's stack except for the first before
    // calling webkitExitFullscreen():
    Vector<RefPtr<Element> > replacementFullscreenElementStack;
    replacementFullscreenElementStack.append(fullscreenElementFrom(document()->topDocument()));
    FullscreenElementStack* topFullscreenElementStack = from(document()->topDocument());
    topFullscreenElementStack->m_fullScreenElementStack.swap(replacementFullscreenElementStack);
    topFullscreenElementStack->webkitExitFullscreen();
}

void FullscreenElementStack::webkitExitFullscreen()
{
    // The exitFullscreen() method must run these steps:

    // 1. Let doc be the context object. (i.e. "this")
    Document* currentDoc = document();

    // 2. If doc's fullscreen element stack is empty, terminate these steps.
    if (m_fullScreenElementStack.isEmpty())
        return;

    // 3. Let descendants be all the doc's descendant browsing context's documents with a non-empty fullscreen
    // element stack (if any), ordered so that the child of the doc is last and the document furthest
    // away from the doc is first.
    Deque<RefPtr<Document> > descendants;
    for (Frame* descendant = document()->frame() ?  document()->frame()->tree().traverseNext() : 0; descendant; descendant = descendant->tree().traverseNext()) {
        if (fullscreenElementFrom(descendant->document()))
            descendants.prepend(descendant->document());
    }

    // 4. For each descendant in descendants, empty descendant's fullscreen element stack, and queue a
    // task to fire an event named fullscreenchange with its bubbles attribute set to true on descendant.
    for (Deque<RefPtr<Document> >::iterator i = descendants.begin(); i != descendants.end(); ++i) {
        from(i->get())->clearFullscreenElementStack();
        addDocumentToFullScreenChangeEventQueue(i->get());
    }

    // 5. While doc is not null, run these substeps:
    Element* newTop = 0;
    while (currentDoc) {
        // 1. Pop the top element of doc's fullscreen element stack.
        from(currentDoc)->popFullscreenElementStack();

        //    If doc's fullscreen element stack is non-empty and the element now at the top is either
        //    not in a document or its node document is not doc, repeat this substep.
        newTop = fullscreenElementFrom(currentDoc);
        if (newTop && (!newTop->inDocument() || newTop->document() != currentDoc))
            continue;

        // 2. Queue a task to fire an event named fullscreenchange with its bubbles attribute set to true
        // on doc.
        addDocumentToFullScreenChangeEventQueue(currentDoc);

        // 3. If doc's fullscreen element stack is empty and doc's browsing context has a browsing context
        // container, set doc to that browsing context container's node document.
        if (!newTop && currentDoc->ownerElement()) {
            currentDoc = &currentDoc->ownerElement()->document();
            continue;
        }

        // 4. Otherwise, set doc to null.
        currentDoc = 0;
    }

    // 6. Return, and run the remaining steps asynchronously.
    // 7. Optionally, perform some animation.

    if (!document()->page())
        return;

    // Only exit out of full screen window mode if there are no remaining elements in the
    // full screen stack.
    if (!newTop) {
        document()->page()->chrome().client().exitFullScreenForElement(m_fullScreenElement.get());
        return;
    }

    // Otherwise, notify the chrome of the new full screen element.
    document()->page()->chrome().client().enterFullScreenForElement(newTop);
}

bool FullscreenElementStack::webkitFullscreenEnabled(Document* document)
{
    // 4. The fullscreenEnabled attribute must return true if the context object and all ancestor
    // browsing context's documents have their fullscreen enabled flag set, or false otherwise.

    // Top-level browsing contexts are implied to have their allowFullScreen attribute set.
    return isAttributeOnAllOwners(allowfullscreenAttr, webkitallowfullscreenAttr, document->ownerElement());

}

void FullscreenElementStack::webkitWillEnterFullScreenForElement(Element* element)
{
    if (!document()->isActive())
        return;

    ASSERT(element);

    // Protect against being called after the document has been removed from the page.
    if (!document()->settings())
        return;

    ASSERT(document()->settings()->fullScreenEnabled());

    if (m_fullScreenRenderer)
        m_fullScreenRenderer->unwrapRenderer();

    m_fullScreenElement = element;

    // Create a placeholder block for a the full-screen element, to keep the page from reflowing
    // when the element is removed from the normal flow. Only do this for a RenderBox, as only
    // a box will have a frameRect. The placeholder will be created in setFullScreenRenderer()
    // during layout.
    RenderObject* renderer = m_fullScreenElement->renderer();
    bool shouldCreatePlaceholder = renderer && renderer->isBox();
    if (shouldCreatePlaceholder) {
        m_savedPlaceholderFrameRect = toRenderBox(renderer)->frameRect();
        m_savedPlaceholderRenderStyle = RenderStyle::clone(renderer->style());
    }

    if (m_fullScreenElement != document()->documentElement())
        RenderFullScreen::wrapRenderer(renderer, renderer ? renderer->parent() : 0, document());

    m_fullScreenElement->setContainsFullScreenElementOnAncestorsCrossingFrameBoundaries(true);

    document()->recalcStyle(Force);
}

void FullscreenElementStack::webkitDidEnterFullScreenForElement(Element*)
{
    if (!m_fullScreenElement)
        return;

    if (!document()->isActive())
        return;

    m_fullScreenElement->didBecomeFullscreenElement();

    m_fullScreenChangeDelayTimer.startOneShot(0);
}

void FullscreenElementStack::webkitWillExitFullScreenForElement(Element*)
{
    if (!m_fullScreenElement)
        return;

    if (!document()->isActive())
        return;

    m_fullScreenElement->willStopBeingFullscreenElement();
}

void FullscreenElementStack::webkitDidExitFullScreenForElement(Element*)
{
    if (!m_fullScreenElement)
        return;

    if (!document()->isActive())
        return;

    m_fullScreenElement->setContainsFullScreenElementOnAncestorsCrossingFrameBoundaries(false);

    m_areKeysEnabledInFullScreen = false;

    if (m_fullScreenRenderer)
        m_fullScreenRenderer->unwrapRenderer();

    m_fullScreenElement = 0;
    document()->setNeedsStyleRecalc();

    // When webkitCancelFullScreen is called, we call webkitExitFullScreen on the topDocument(). That
    // means that the events will be queued there. So if we have no events here, start the timer on
    // the exiting document.
    Document* exitingDocument = document();
    if (m_fullScreenChangeEventTargetQueue.isEmpty() && m_fullScreenErrorEventTargetQueue.isEmpty())
        exitingDocument = document()->topDocument();
    from(exitingDocument)->m_fullScreenChangeDelayTimer.startOneShot(0);
}

void FullscreenElementStack::setFullScreenRenderer(RenderFullScreen* renderer)
{
    if (renderer == m_fullScreenRenderer)
        return;

    if (renderer && m_savedPlaceholderRenderStyle) {
        renderer->createPlaceholder(m_savedPlaceholderRenderStyle.release(), m_savedPlaceholderFrameRect);
    } else if (renderer && m_fullScreenRenderer && m_fullScreenRenderer->placeholder()) {
        RenderBlock* placeholder = m_fullScreenRenderer->placeholder();
        renderer->createPlaceholder(RenderStyle::clone(placeholder->style()), placeholder->frameRect());
    }

    if (m_fullScreenRenderer)
        m_fullScreenRenderer->destroy();
    ASSERT(!m_fullScreenRenderer);

    m_fullScreenRenderer = renderer;
}

void FullscreenElementStack::fullScreenRendererDestroyed()
{
    m_fullScreenRenderer = 0;
}

void FullscreenElementStack::fullScreenChangeDelayTimerFired(Timer<FullscreenElementStack>*)
{
    // Since we dispatch events in this function, it's possible that the
    // document will be detached and GC'd. We protect it here to make sure we
    // can finish the function successfully.
    RefPtr<Document> protectDocument(document());
    Deque<RefPtr<Node> > changeQueue;
    m_fullScreenChangeEventTargetQueue.swap(changeQueue);
    Deque<RefPtr<Node> > errorQueue;
    m_fullScreenErrorEventTargetQueue.swap(errorQueue);

    while (!changeQueue.isEmpty()) {
        RefPtr<Node> node = changeQueue.takeFirst();
        if (!node)
            node = document()->documentElement();
        // The dispatchEvent below may have blown away our documentElement.
        if (!node)
            continue;

        // If the element was removed from our tree, also message the documentElement. Since we may
        // have a document hierarchy, check that node isn't in another document.
        if (!document()->contains(node.get()) && !node->inDocument())
            changeQueue.append(document()->documentElement());

        node->dispatchEvent(Event::createBubble(EventTypeNames::webkitfullscreenchange));
    }

    while (!errorQueue.isEmpty()) {
        RefPtr<Node> node = errorQueue.takeFirst();
        if (!node)
            node = document()->documentElement();
        // The dispatchEvent below may have blown away our documentElement.
        if (!node)
            continue;

        // If the element was removed from our tree, also message the documentElement. Since we may
        // have a document hierarchy, check that node isn't in another document.
        if (!document()->contains(node.get()) && !node->inDocument())
            errorQueue.append(document()->documentElement());

        node->dispatchEvent(Event::createBubble(EventTypeNames::webkitfullscreenerror));
    }
}

void FullscreenElementStack::fullScreenElementRemoved()
{
    m_fullScreenElement->setContainsFullScreenElementOnAncestorsCrossingFrameBoundaries(false);
    webkitCancelFullScreen();
}

void FullscreenElementStack::removeFullScreenElementOfSubtree(Node* node, bool amongChildrenOnly)
{
    if (!m_fullScreenElement)
        return;

    bool elementInSubtree = false;
    if (amongChildrenOnly)
        elementInSubtree = m_fullScreenElement->isDescendantOf(node);
    else
        elementInSubtree = (m_fullScreenElement == node) || m_fullScreenElement->isDescendantOf(node);

    if (elementInSubtree)
        fullScreenElementRemoved();
}

void FullscreenElementStack::clearFullscreenElementStack()
{
    m_fullScreenElementStack.clear();
}

void FullscreenElementStack::popFullscreenElementStack()
{
    if (m_fullScreenElementStack.isEmpty())
        return;

    m_fullScreenElementStack.removeLast();
}

void FullscreenElementStack::pushFullscreenElementStack(Element* element)
{
    m_fullScreenElementStack.append(element);
}

void FullscreenElementStack::addDocumentToFullScreenChangeEventQueue(Document* doc)
{
    ASSERT(doc);

    Node* target = 0;
    if (FullscreenElementStack* fullscreen = fromIfExists(doc)) {
        target = fullscreen->webkitFullscreenElement();
        if (!target)
            target = fullscreen->webkitCurrentFullScreenElement();
    }

    if (!target)
        target = doc;
    m_fullScreenChangeEventTargetQueue.append(target);
}

} // namespace WebCore