/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple 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 "sky/engine/config.h"
#include "sky/engine/core/rendering/RenderView.h"

#include "gen/sky/platform/RuntimeEnabledFeatures.h"
#include "sky/engine/core/dom/Document.h"
#include "sky/engine/core/dom/Element.h"
#include "sky/engine/core/frame/LocalFrame.h"
#include "sky/engine/core/page/Page.h"
#include "sky/engine/core/rendering/HitTestResult.h"
#include "sky/engine/core/rendering/RenderGeometryMap.h"
#include "sky/engine/core/rendering/RenderLayer.h"
#include "sky/engine/platform/TraceEvent.h"
#include "sky/engine/platform/geometry/FloatQuad.h"
#include "sky/engine/platform/geometry/TransformState.h"
#include "sky/engine/platform/graphics/GraphicsContext.h"

namespace blink {

RenderView::RenderView(Document* document)
    : RenderBlockFlow(document)
    , m_frameView(document->view())
    , m_selectionStart(nullptr)
    , m_selectionEnd(nullptr)
    , m_selectionStartPos(-1)
    , m_selectionEndPos(-1)
    , m_layoutState(0)
    , m_renderCounterCount(0)
    , m_hitTestCount(0)
{
    // init RenderObject attributes
    setInline(false);

    m_minPreferredLogicalWidth = 0;
    m_maxPreferredLogicalWidth = 0;

    setPreferredLogicalWidthsDirty(MarkOnlyThis);

    setPositionState(AbsolutePosition); // to 0,0 :)
}

RenderView::~RenderView()
{
}

bool RenderView::hitTest(const HitTestRequest& request, HitTestResult& result)
{
    return hitTest(request, result.hitTestLocation(), result);
}

bool RenderView::hitTest(const HitTestRequest& request, const HitTestLocation& location, HitTestResult& result)
{
    TRACE_EVENT0("blink", "RenderView::hitTest");
    m_hitTestCount++;

    if (!m_frameView->visibleContentRect().contains(location.roundedPoint()))
        return false;

    // We have to recursively update layout/style here because otherwise, when the hit test recurses
    // into a child document, it could trigger a layout on the parent document, which can destroy RenderLayers
    // that are higher up in the call stack, leading to crashes.
    // Note that Document::updateLayout calls its parent's updateLayout.
    // FIXME: It should be the caller's responsibility to ensure an up-to-date layout.
    frameView()->updateLayoutAndStyleIfNeededRecursive();

    // RenderView should make sure to update layout before entering hit testing
    ASSERT(!frame()->view()->layoutPending());
    ASSERT(!document().renderView()->needsLayout());

    // TODO(ojan): Does any of this intersection stuff make sense for Sky?
    LayoutRect hitTestArea = view()->documentRect();
    if (!request.ignoreClipping())
        hitTestArea.intersect(frame()->view()->visibleContentRect());

    bool insideLayer = layer()->hitTestLayer(layer(), 0, request, result, hitTestArea, location);
    if (!insideLayer) {
        // TODO(ojan): Is this code needed for Sky?

        // We didn't hit any layer. If we are the root layer and the mouse is -- or just was -- down,
        // return ourselves. We do this so mouse events continue getting delivered after a drag has
        // exited the WebView, and so hit testing over a scrollbar hits the content document.
        if (request.active() || request.release()) {
            updateHitTestResult(result, location.point());
            insideLayer = true;
        }
    }
    return insideLayer;
}

void RenderView::computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit, LogicalExtentComputedValues& computedValues) const
{
    computedValues.m_extent = m_frameView ? LayoutUnit(viewLogicalHeight()) : logicalHeight;
}

void RenderView::updateLogicalWidth()
{
    if (m_frameView)
        setLogicalWidth(viewLogicalWidth());
}

LayoutUnit RenderView::availableLogicalHeight(AvailableLogicalHeightType heightType) const
{
    return RenderBlockFlow::availableLogicalHeight(heightType);
}

bool RenderView::isChildAllowed(RenderObject* child, RenderStyle*) const
{
    return child->isBox();
}

void RenderView::layoutContent()
{
    ASSERT(needsLayout());

    RenderBlockFlow::layout();

#if ENABLE(ASSERT)
    checkLayoutState();
#endif
}

#if ENABLE(ASSERT)
void RenderView::checkLayoutState()
{
    ASSERT(!m_layoutState->next());
}
#endif

void RenderView::layout()
{
    SubtreeLayoutScope layoutScope(*this);

    bool relayoutChildren = (!m_frameView || width() != viewWidth() || height() != viewHeight());
    if (relayoutChildren) {
        layoutScope.setChildNeedsLayout(this);
        for (RenderObject* child = firstChild(); child; child = child->nextSibling()) {
            if ((child->isBox() && toRenderBox(child)->hasRelativeLogicalHeight())
                    || child->style()->logicalHeight().isPercent()
                    || child->style()->logicalMinHeight().isPercent()
                    || child->style()->logicalMaxHeight().isPercent())
                layoutScope.setChildNeedsLayout(child);
        }
    }

    ASSERT(!m_layoutState);
    if (!needsLayout())
        return;

    LayoutState rootLayoutState(*this);

    layoutContent();

#if ENABLE(ASSERT)
    checkLayoutState();
#endif
    clearNeedsLayout();
}

void RenderView::mapLocalToContainer(const RenderLayerModelObject* paintInvalidationContainer, TransformState& transformState, MapCoordinatesFlags mode) const
{
    if (!paintInvalidationContainer && mode & UseTransforms && shouldUseTransformFromContainer(0)) {
        TransformationMatrix t;
        getTransformFromContainer(0, LayoutSize(), t);
        transformState.applyTransform(t);
    }
}

const RenderObject* RenderView::pushMappingToContainer(const RenderLayerModelObject* ancestorToStopAt, RenderGeometryMap& geometryMap) const
{
    LayoutSize offset;
    RenderObject* container = 0;

    // If a container was specified, and was not 0 or the RenderView, then we
    // should have found it by now unless we're traversing to a parent document.
    ASSERT_ARG(ancestorToStopAt, !ancestorToStopAt || ancestorToStopAt == this || container);

    if ((!ancestorToStopAt || container) && shouldUseTransformFromContainer(container)) {
        TransformationMatrix t;
        getTransformFromContainer(container, LayoutSize(), t);
        geometryMap.push(this, t, false, false, true);
    } else {
        geometryMap.push(this, offset, false, false, false);
    }

    return container;
}

void RenderView::mapAbsoluteToLocalPoint(MapCoordinatesFlags mode, TransformState& transformState) const
{
    if (mode & UseTransforms && shouldUseTransformFromContainer(0)) {
        TransformationMatrix t;
        getTransformFromContainer(0, LayoutSize(), t);
        transformState.applyTransform(t);
    }
}

void RenderView::paint(PaintInfo& paintInfo, const LayoutPoint& paintOffset, Vector<RenderBox*>& layers)
{
    // If we ever require layout but receive a paint anyway, something has gone horribly wrong.
    ASSERT(!needsLayout());
    // RenderViews should never be called to paint with an offset not on device pixels.
    ASSERT(LayoutPoint(IntPoint(paintOffset.x(), paintOffset.y())) == paintOffset);

    // This avoids painting garbage between columns if there is a column gap.
    if (m_frameView && style()->isOverflowPaged())
        paintInfo.context->fillRect(paintInfo.rect, m_frameView->baseBackgroundColor());

    paintObject(paintInfo, paintOffset, layers);
}

void RenderView::paintBoxDecorationBackground(PaintInfo& paintInfo, const LayoutPoint&)
{
    if (!view())
        return;

    // This code typically only executes if the root element's visibility has been set to hidden,
    // if there is a transform on the <html>, or if there is a page scale factor less than 1.
    // Only fill with the base background color (typically white) if we're the root document,
    // since iframes/frames with no background in the child document should show the parent's background.
    if (!frameView()->isTransparent()) {
        Color baseColor = frameView()->baseBackgroundColor();
        if (baseColor.alpha()) {
            CompositeOperator previousOperator = paintInfo.context->compositeOperation();
            paintInfo.context->setCompositeOperation(CompositeCopy);
            paintInfo.context->fillRect(paintInfo.rect, baseColor);
            paintInfo.context->setCompositeOperation(previousOperator);
        } else {
            paintInfo.context->clearRect(paintInfo.rect);
        }
    }
}

void RenderView::absoluteQuads(Vector<FloatQuad>& quads) const
{
    quads.append(FloatRect(FloatPoint(), layer()->size()));
}

static RenderObject* rendererAfterPosition(RenderObject* object, unsigned offset)
{
    if (!object)
        return 0;

    RenderObject* child = object->childAt(offset);
    return child ? child : object->nextInPreOrderAfterChildren();
}

// When exploring the RenderTree looking for the nodes involved in the Selection, sometimes it's
// required to change the traversing direction because the "start" position is below the "end" one.
static inline RenderObject* getNextOrPrevRenderObjectBasedOnDirection(const RenderObject* o, const RenderObject* stop, bool& continueExploring, bool& exploringBackwards)
{
    RenderObject* next;
    if (exploringBackwards) {
        next = o->previousInPreOrder();
        continueExploring = next && !(next)->isRenderView();
    } else {
        next = o->nextInPreOrder();
        continueExploring = next && next != stop;
        exploringBackwards = !next && (next != stop);
        if (exploringBackwards) {
            next = stop->previousInPreOrder();
            continueExploring = next && !next->isRenderView();
        }
    }

    return next;
}

void RenderView::setSelection(RenderObject* start, int startPos, RenderObject* end, int endPos)
{
    // This code makes no assumptions as to if the rendering tree is up to date or not
    // and will not try to update it. Currently clearSelection calls this
    // (intentionally) without updating the rendering tree as it doesn't care.
    // Other callers may want to force recalc style before calling this.

    // Make sure both our start and end objects are defined.
    // Check www.msnbc.com and try clicking around to find the case where this happened.
    if ((start && !end) || (end && !start))
        return;

    // Just return if the selection hasn't changed.
    if (m_selectionStart == start && m_selectionStartPos == startPos &&
        m_selectionEnd == end && m_selectionEndPos == endPos)
        return;

    RenderObject* os = m_selectionStart;
    RenderObject* stop = rendererAfterPosition(m_selectionEnd, m_selectionEndPos);
    bool exploringBackwards = false;
    bool continueExploring = os && (os != stop);
    while (continueExploring) {
        if ((os->canBeSelectionLeaf() || os == m_selectionStart || os == m_selectionEnd) && os->selectionState() != SelectionNone) {
            os->setSelectionStateIfNeeded(SelectionNone);
        }

        os = getNextOrPrevRenderObjectBasedOnDirection(os, stop, continueExploring, exploringBackwards);
    }

    // set selection start and end
    m_selectionStart = start;
    m_selectionStartPos = startPos;
    m_selectionEnd = end;
    m_selectionEndPos = endPos;

    // Update the selection status of all objects between m_selectionStart and m_selectionEnd
    if (start && start == end) {
        start->setSelectionStateIfNeeded(SelectionBoth);
    } else {
        if (start)
            start->setSelectionStateIfNeeded(SelectionStart);
        if (end)
            end->setSelectionStateIfNeeded(SelectionEnd);
    }

    RenderObject* o = start;
    stop = rendererAfterPosition(end, endPos);

    while (o && o != stop) {
        if (o != start && o != end && o->canBeSelectionLeaf())
            o->setSelectionStateIfNeeded(SelectionInside);
        o = o->nextInPreOrder();
    }
}

void RenderView::getSelection(RenderObject*& startRenderer, int& startOffset, RenderObject*& endRenderer, int& endOffset) const
{
    startRenderer = m_selectionStart;
    startOffset = m_selectionStartPos;
    endRenderer = m_selectionEnd;
    endOffset = m_selectionEndPos;
}

void RenderView::clearSelection()
{
    setSelection(0, -1, 0, -1);
}

void RenderView::selectionStartEnd(int& startPos, int& endPos) const
{
    startPos = m_selectionStartPos;
    endPos = m_selectionEndPos;
}

LayoutRect RenderView::viewRect() const
{
    if (m_frameView)
        return m_frameView->visibleContentRect();
    return LayoutRect();
}

IntRect RenderView::unscaledDocumentRect() const
{
    return pixelSnappedIntRect(layoutOverflowRect());
}

LayoutRect RenderView::backgroundRect(RenderBox* backgroundRenderer) const
{
    return unscaledDocumentRect();
}

IntRect RenderView::documentRect() const
{
    FloatRect overflowRect(unscaledDocumentRect());
    if (hasTransform())
        overflowRect = layer()->currentTransform().mapRect(overflowRect);
    return IntRect(overflowRect);
}

int RenderView::viewHeight() const
{
    if (m_frameView)
        return m_frameView->layoutSize().height();
    return 0;
}

int RenderView::viewWidth() const
{
    if (m_frameView)
        return m_frameView->layoutSize().width();
    return 0;
}

int RenderView::viewLogicalHeight() const
{
    return viewHeight();
}

LayoutUnit RenderView::viewLogicalHeightForPercentages() const
{
    return viewLogicalHeight();
}

void RenderView::pushLayoutState(LayoutState& layoutState)
{
    m_layoutState = &layoutState;
}

void RenderView::popLayoutState()
{
    ASSERT(m_layoutState);
    m_layoutState = m_layoutState->next();
}

// FIXME(sky): remove
double RenderView::layoutViewportWidth() const
{
    return viewWidth();
}

// FIXME(sky): remove
double RenderView::layoutViewportHeight() const
{
    return viewHeight();
}

void RenderView::addIFrame(RenderIFrame* iframe)
{
    m_iframes.add(iframe);
}

void RenderView::removeIFrame(RenderIFrame* iframe)
{
    m_iframes.remove(iframe);
}

void RenderView::updateIFramesAfterLayout()
{
    for (auto& iframe: m_iframes)
        iframe->updateWidgetBounds();
}

} // namespace blink