/*
 * Copyright (C) 2013 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:
 *
 *     * 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
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "web/FullscreenController.h"

#include "core/dom/Document.h"
#include "core/dom/Fullscreen.h"
#include "core/frame/FrameView.h"
#include "core/frame/LocalFrame.h"
#include "core/frame/PageScaleConstraintsSet.h"
#include "core/html/HTMLMediaElement.h"
#include "core/html/HTMLVideoElement.h"
#include "core/layout/LayoutFullScreen.h"
#include "platform/RuntimeEnabledFeatures.h"
#include "public/platform/WebLayerTreeView.h"
#include "public/web/WebFrameClient.h"
#include "web/WebLocalFrameImpl.h"
#include "web/WebSettingsImpl.h"
#include "web/WebViewImpl.h"

namespace blink {

FullscreenController* FullscreenController::create(WebViewImpl* webViewImpl) {
  return new FullscreenController(webViewImpl);
}

FullscreenController::FullscreenController(WebViewImpl* webViewImpl)
    : m_webViewImpl(webViewImpl),
      m_haveEnteredFullscreen(false),
      m_exitFullscreenPageScaleFactor(0),
      m_needsScrollAndScaleRestore(false),
      m_isCancelingFullscreen(false) {}

void FullscreenController::didEnterFullscreen() {
  if (!m_provisionalFullscreenElement)
    return;

  Element* element = m_provisionalFullscreenElement.release();
  Document& document = element->document();
  m_fullscreenFrame = document.frame();

  if (!m_fullscreenFrame)
    return;

  if (!m_haveEnteredFullscreen) {
    updatePageScaleConstraints(false);
    m_webViewImpl->setPageScaleFactor(1.0f);
    if (m_webViewImpl->mainFrame()->isWebLocalFrame())
      m_webViewImpl->mainFrame()->setScrollOffset(WebSize());
    m_webViewImpl->setVisualViewportOffset(FloatPoint());
    m_haveEnteredFullscreen = true;
  }

  Fullscreen::from(document).didEnterFullscreenForElement(element);
  DCHECK_EQ(Fullscreen::currentFullScreenElementFrom(document), element);

  if (isHTMLVideoElement(element)) {
    HTMLVideoElement* videoElement = toHTMLVideoElement(element);
    if (videoElement->usesOverlayFullscreenVideo() &&
        m_webViewImpl->layerTreeView())
      m_webViewImpl->layerTreeView()->setHasTransparentBackground(true);
  }
}

void FullscreenController::didExitFullscreen() {
  if (!m_fullscreenFrame)
    return;

  if (m_haveEnteredFullscreen)
    updatePageScaleConstraints(true);

  if (Document* document = m_fullscreenFrame->document()) {
    if (Fullscreen* fullscreen = Fullscreen::fromIfExists(*document)) {
      Element* element = fullscreen->currentFullScreenElement();
      if (element) {
        // When the client exits from full screen we have to call
        // fullyExitFullscreen to notify the document. While doing that,
        // suppress notifications back to the client.
        m_isCancelingFullscreen = true;
        Fullscreen::fullyExitFullscreen(*document);
        m_isCancelingFullscreen = false;

        // If the video used overlay fullscreen mode, the background was made
        // transparent. Restore the transparency.
        if (isHTMLVideoElement(element) && m_webViewImpl->layerTreeView())
          m_webViewImpl->layerTreeView()->setHasTransparentBackground(
              m_webViewImpl->isTransparent());

        // We need to wait until style and layout are updated in order
        // to propertly restore scroll offsets since content may not be
        // overflowing in the same way until they do.
        if (m_haveEnteredFullscreen)
          m_needsScrollAndScaleRestore = true;

        fullscreen->didExitFullscreen();
      }
    }
  }

  m_haveEnteredFullscreen = false;
  m_fullscreenFrame.clear();
}

void FullscreenController::enterFullscreenForElement(Element* element) {
  // We are already transitioning to fullscreen for a different element.
  if (m_provisionalFullscreenElement) {
    m_provisionalFullscreenElement = element;
    return;
  }

  // We are already in fullscreen mode.
  if (m_fullscreenFrame) {
    m_provisionalFullscreenElement = element;
    didEnterFullscreen();
    return;
  }

  // We need to store these values here rather than didEnterFullscreen since
  // by the time the latter is called, a Resize has already occured, clamping
  // the scroll offset. Don't save values if we're still waiting to restore
  // a previous set. This can happen if we exit and quickly reenter fullscreen
  // without performing a layout.
  if (!m_haveEnteredFullscreen && !m_needsScrollAndScaleRestore) {
    m_exitFullscreenPageScaleFactor = m_webViewImpl->pageScaleFactor();
    m_exitFullscreenScrollOffset =
        m_webViewImpl->mainFrame()->isWebLocalFrame()
            ? m_webViewImpl->mainFrame()->scrollOffset()
            : WebSize();
    m_exitFullscreenVisualViewportOffset =
        m_webViewImpl->visualViewportOffset();
  }

  // We need to transition to fullscreen mode.
  WebLocalFrameImpl* frame =
      WebLocalFrameImpl::fromFrame(element->document().frame());
  if (frame && frame->client()) {
    if (!Fullscreen::from(element->document()).forCrossProcessDescendant())
      frame->client()->enterFullscreen();
    m_provisionalFullscreenElement = element;
  }
}

void FullscreenController::exitFullscreen(LocalFrame* frame) {
  DCHECK(frame);

  // The client is exiting full screen, so don't send a notification.
  if (m_isCancelingFullscreen)
    return;

  WebLocalFrameImpl* webFrame = WebLocalFrameImpl::fromFrame(frame);
  if (webFrame && webFrame->client())
    webFrame->client()->exitFullscreen();
}

void FullscreenController::updateSize() {
  if (!isFullscreen())
    return;

  updatePageScaleConstraints(false);

  LayoutFullScreen* layoutObject =
      Fullscreen::from(*m_fullscreenFrame->document()).fullScreenLayoutObject();
  if (layoutObject)
    layoutObject->updateStyle();
}

void FullscreenController::didUpdateLayout() {
  if (!m_needsScrollAndScaleRestore)
    return;

  // If we re-entered fullscreen before we could restore the scroll and scale
  // don't try restoring them yet.
  if (isFullscreen())
    return;

  m_webViewImpl->setPageScaleFactor(m_exitFullscreenPageScaleFactor);
  if (m_webViewImpl->mainFrame()->isWebLocalFrame())
    m_webViewImpl->mainFrame()->setScrollOffset(
        WebSize(m_exitFullscreenScrollOffset));
  m_webViewImpl->setVisualViewportOffset(m_exitFullscreenVisualViewportOffset);
  m_needsScrollAndScaleRestore = false;
}

void FullscreenController::updatePageScaleConstraints(bool removeConstraints) {
  PageScaleConstraints fullscreenConstraints;
  if (!removeConstraints) {
    fullscreenConstraints = PageScaleConstraints(1.0, 1.0, 1.0);
    fullscreenConstraints.layoutSize = FloatSize(m_webViewImpl->size());
  }
  m_webViewImpl->pageScaleConstraintsSet().setFullscreenConstraints(
      fullscreenConstraints);
  m_webViewImpl->pageScaleConstraintsSet().computeFinalConstraints();

  // Although we called computedFinalConstraints() above, the "final"
  // constraints are not actually final. They are still subject to scale factor
  // clamping by contents size.  Normally they should be dirtied due to
  // contents size mutation after layout, however the contents size is not
  // guaranteed to mutate, and the scale factor may remain unclamped.  Just
  // fire the event again to ensure the final constraints pick up the latest
  // contents size.
  m_webViewImpl->didChangeContentsSize();
  if (m_webViewImpl->mainFrameImpl() &&
      m_webViewImpl->mainFrameImpl()->frameView())
    m_webViewImpl->mainFrameImpl()->frameView()->setNeedsLayout();

  m_webViewImpl->updateMainFrameLayoutSize();
}

DEFINE_TRACE(FullscreenController) {
  visitor->trace(m_provisionalFullscreenElement);
  visitor->trace(m_fullscreenFrame);
}

}  // namespace blink