/*
 * 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
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "PageScaleConstraintsSet.h"

namespace WebCore {

static const float defaultMinimumScale = 0.25f;
static const float defaultMaximumScale = 5.0f;

PageScaleConstraintsSet::PageScaleConstraintsSet()
    : m_lastContentsWidth(0)
    , m_needsReset(false)
    , m_constraintsDirty(false)
{
    m_finalConstraints = defaultConstraints();
}

PageScaleConstraints PageScaleConstraintsSet::defaultConstraints() const
{
    return PageScaleConstraints(-1, defaultMinimumScale, defaultMaximumScale);
}

void PageScaleConstraintsSet::updatePageDefinedConstraints(const ViewportArguments& arguments, IntSize viewSize, int layoutFallbackWidth)
{
    m_pageDefinedConstraints = arguments.resolve(viewSize, layoutFallbackWidth);

    m_constraintsDirty = true;
}

void PageScaleConstraintsSet::setUserAgentConstraints(const PageScaleConstraints& userAgentConstraints)
{
    m_userAgentConstraints = userAgentConstraints;
    m_constraintsDirty = true;
}

void PageScaleConstraintsSet::computeFinalConstraints()
{
    m_finalConstraints = defaultConstraints();
    m_finalConstraints.overrideWith(m_pageDefinedConstraints);
    m_finalConstraints.overrideWith(m_userAgentConstraints);

    m_constraintsDirty = false;
}

void PageScaleConstraintsSet::adjustFinalConstraintsToContentsSize(IntSize viewSize, IntSize contentsSize, int nonOverlayScrollbarWidth)
{
    m_finalConstraints.fitToContentsWidth(contentsSize.width(), viewSize.width() - nonOverlayScrollbarWidth);
}

void PageScaleConstraintsSet::setNeedsReset(bool needsReset)
{
    m_needsReset = needsReset;
    if (needsReset)
        m_constraintsDirty = true;
}

void PageScaleConstraintsSet::didChangeContentsSize(IntSize contentsSize, float pageScaleFactor)
{
    // If a large fixed-width element expanded the size of the document
    // late in loading and our initial scale is not constrained, reset the
    // page scale factor to the new minimum scale.
    if (contentsSize.width() > m_lastContentsWidth
        && pageScaleFactor == finalConstraints().minimumScale
        && userAgentConstraints().initialScale == -1 && pageDefinedConstraints().initialScale == -1)
        setNeedsReset(true);

    m_constraintsDirty = true;
    m_lastContentsWidth = contentsSize.width();
}

static float computeDeprecatedTargetDensityDPIFactor(const ViewportArguments& arguments, float deviceScaleFactor)
{
    if (arguments.deprecatedTargetDensityDPI == ViewportArguments::ValueDeviceDPI)
        return 1.0f / deviceScaleFactor;

    float targetDPI = -1.0f;
    if (arguments.deprecatedTargetDensityDPI == ViewportArguments::ValueLowDPI)
        targetDPI = 120.0f;
    else if (arguments.deprecatedTargetDensityDPI == ViewportArguments::ValueMediumDPI)
        targetDPI = 160.0f;
    else if (arguments.deprecatedTargetDensityDPI == ViewportArguments::ValueHighDPI)
        targetDPI = 240.0f;
    else if (arguments.deprecatedTargetDensityDPI != ViewportArguments::ValueAuto)
        targetDPI = arguments.deprecatedTargetDensityDPI;
    return targetDPI > 0 ? 160.0f / targetDPI : 1.0f;
}

static float getLayoutWidthForNonWideViewport(const FloatSize& deviceSize, float initialScale)
{
    return initialScale == -1 ? deviceSize.width() : deviceSize.width() / initialScale;
}

void PageScaleConstraintsSet::adjustPageDefinedConstraintsForAndroidWebView(const ViewportArguments& arguments, IntSize viewSize, int layoutFallbackWidth, float deviceScaleFactor, bool useWideViewport, bool loadWithOverviewMode)
{
    float initialScale = m_pageDefinedConstraints.initialScale;
    if (arguments.zoom == -1 && !loadWithOverviewMode) {
        if (arguments.width == -1 || (useWideViewport && arguments.width != ViewportArguments::ValueDeviceWidth))
            m_pageDefinedConstraints.initialScale = 1.0f;
    }

    float targetDensityDPIFactor = computeDeprecatedTargetDensityDPIFactor(arguments, deviceScaleFactor);
    if (m_pageDefinedConstraints.initialScale != -1)
        m_pageDefinedConstraints.initialScale *= targetDensityDPIFactor;
    m_pageDefinedConstraints.minimumScale *= targetDensityDPIFactor;
    m_pageDefinedConstraints.maximumScale *= targetDensityDPIFactor;

    float adjustedLayoutSizeWidth = m_pageDefinedConstraints.layoutSize.width();
    if (useWideViewport && arguments.width == -1 && arguments.zoom != 1.0f)
        adjustedLayoutSizeWidth = layoutFallbackWidth;
    else {
        if (!useWideViewport)
            adjustedLayoutSizeWidth = getLayoutWidthForNonWideViewport(viewSize, initialScale);
        if (!useWideViewport || arguments.width == -1 || arguments.width == ViewportArguments::ValueDeviceWidth)
            adjustedLayoutSizeWidth /= targetDensityDPIFactor;
    }

    ASSERT(m_pageDefinedConstraints.layoutSize.width() > 0);
    float adjustedLayoutSizeHeight = (adjustedLayoutSizeWidth * m_pageDefinedConstraints.layoutSize.height()) / m_pageDefinedConstraints.layoutSize.width();
    m_pageDefinedConstraints.layoutSize.setWidth(adjustedLayoutSizeWidth);
    m_pageDefinedConstraints.layoutSize.setHeight(adjustedLayoutSizeHeight);
}

} // namespace WebCore