/**************************************************************************
**
** This file is part of Qt Creator
**
** Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).
**
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** Commercial Usage
**
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** GNU Lesser General Public License Usage
**
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at http://qt.nokia.com/contact.
**
**************************************************************************/

#include "stylehelper.h"

#include <QPixmapCache>
#include <QWidget>
#include <QtCore/QRect>
#include <QPainter>
#include <QApplication>
#include <QPalette>
#include <QStyleOption>
#include <QtCore/QObject>

// Clamps float color values within (0, 255)
static int clamp(float x)
{
    const int val = x > 255 ? 255 : static_cast<int>(x);
    return val < 0 ? 0 : val;
}

namespace Utils
{

qreal StyleHelper::sidebarFontSize()
{
#if defined(Q_OS_MACOS)
    return 10;
#else
    return 7.5;
#endif
}

QColor StyleHelper::panelTextColor(bool lightColored)
{
    if (!lightColored) {
        return Qt::white;
    }
    else {
        return Qt::black;
    }
}

// Invalid by default, setBaseColor needs to be called at least once
QColor StyleHelper::m_baseColor;
QColor StyleHelper::m_requestedBaseColor;

QColor StyleHelper::baseColor(bool lightColored)
{
    if (!lightColored) {
        return m_baseColor;
    }
    else {
        return m_baseColor.lighter(230);
    }
}

QColor StyleHelper::highlightColor(bool lightColored)
{
    QColor result = baseColor(lightColored);
    if (!lightColored)
        result.setHsv(result.hue(),
                      clamp(result.saturation()),
                      clamp(result.value() * 1.16));
    else
        result.setHsv(result.hue(),
                      clamp(result.saturation()),
                      clamp(result.value() * 1.06));
    return result;
}

QColor StyleHelper::shadowColor(bool lightColored)
{
    QColor result = baseColor(lightColored);
    result.setHsv(result.hue(),
                  clamp(result.saturation() * 1.1),
                  clamp(result.value() * 0.70));
    return result;
}

QColor StyleHelper::borderColor(bool lightColored)
{
    QColor result = baseColor(lightColored);
    result.setHsv(result.hue(),
                  result.saturation(),
                  result.value() / 2);
    return result;
}

// We try to ensure that the actual color used are within
// reasonalbe bounds while generating the actual baseColor
// from the users request.
void StyleHelper::setBaseColor(const QColor &newcolor)
{
    m_requestedBaseColor = newcolor;

    QColor color;
    color.setHsv(newcolor.hue(),
                 newcolor.saturation() * 0.7,
                 64 + newcolor.value() / 3);

    if (color.isValid() && color != m_baseColor) {
        m_baseColor = color;

        auto const l_topLevelWidgets = QApplication::topLevelWidgets();
        for (QWidget* w : l_topLevelWidgets) {
            w->update();
        }
    }
}

static void verticalGradientHelper(QPainter* p, const QRect &spanRect, const QRect &rect, bool lightColored)
{
    QColor highlight = StyleHelper::highlightColor(lightColored);
    QColor shadow = StyleHelper::shadowColor(lightColored);
    QLinearGradient grad(spanRect.topRight(), spanRect.topLeft());
    grad.setColorAt(0, highlight.lighter(117));
    grad.setColorAt(1, shadow.darker(109));
    p->fillRect(rect, grad);

    QColor light(255, 255, 255, 80);
    p->setPen(light);
    p->drawLine(rect.topRight() - QPoint(1, 0), rect.bottomRight() - QPoint(1, 0));
    QColor dark(0, 0, 0, 90);
    p->setPen(dark);
    p->drawLine(rect.topLeft(), rect.bottomLeft());
}

void StyleHelper::verticalGradient(QPainter* painter, const QRect &spanRect, const QRect &clipRect, bool lightColored)
{
    if (StyleHelper::usePixmapCache()) {
        QString key;
        QColor keyColor = baseColor(lightColored);
        key.asprintf("mh_vertical %d %d %d %d %d",
                     spanRect.width(), spanRect.height(), clipRect.width(),
                     clipRect.height(), keyColor.rgb());

        QPixmap pixmap;
        if (!QPixmapCache::find(key, &pixmap)) {
            pixmap = QPixmap(clipRect.size());
            QPainter p(&pixmap);
            QRect rect(0, 0, clipRect.width(), clipRect.height());
            verticalGradientHelper(&p, spanRect, rect, lightColored);
            p.end();
            QPixmapCache::insert(key, pixmap);
        }

        painter->drawPixmap(clipRect.topLeft(), pixmap);
    }
    else {
        verticalGradientHelper(painter, spanRect, clipRect, lightColored);
    }
}

// Draws a cached pixmap with shadow
void StyleHelper::drawIconWithShadow(const QIcon &icon, const QRect &rect,
                                     QPainter* p, QIcon::Mode iconMode, int radius, const QColor &color, const QPoint &offset)
{
    QPixmap cache;
    QString pixmapName = QSL("icon %0 %1 %2").arg(icon.cacheKey()).arg(iconMode).arg(rect.height());

    if (!QPixmapCache::find(pixmapName, &cache)) {
        QPixmap px = icon.pixmap(rect.size(), iconMode);
        px.setDevicePixelRatio(qApp->devicePixelRatio());
        cache = QPixmap(px.size() + QSize(radius * 2, radius * 2));
        cache.setDevicePixelRatio(px.devicePixelRatioF());
        cache.fill(Qt::transparent);

        QPainter cachePainter(&cache);

        // Draw shadow
        QImage tmp(px.size() + QSize(radius * 2, radius * 2 + 1), QImage::Format_ARGB32_Premultiplied);
        tmp.setDevicePixelRatio(px.devicePixelRatioF());
        tmp.fill(Qt::transparent);

        QPainter tmpPainter(&tmp);
        tmpPainter.setCompositionMode(QPainter::CompositionMode_Source);
        tmpPainter.drawPixmap(QPoint(radius, radius), px);
        tmpPainter.end();

        // blur the alpha channel
        QImage blurred(tmp.size(), QImage::Format_ARGB32_Premultiplied);
        blurred.fill(Qt::transparent);
        QPainter blurPainter(&blurred);
        qt_blurImage(&blurPainter, tmp, radius, false, true);
        blurPainter.end();

        tmp = blurred;

        // blacken the image...
        tmpPainter.begin(&tmp);
        tmpPainter.setCompositionMode(QPainter::CompositionMode_SourceIn);
        tmpPainter.fillRect(tmp.rect(), color);
        tmpPainter.end();

        tmpPainter.begin(&tmp);
        tmpPainter.setCompositionMode(QPainter::CompositionMode_SourceIn);
        tmpPainter.fillRect(tmp.rect(), color);
        tmpPainter.end();

        // draw the blurred drop shadow...
        cachePainter.drawImage(QRect(0, 0, cache.rect().width() / cache.devicePixelRatioF(), cache.rect().height() / cache.devicePixelRatioF()), tmp);

        // Draw the actual pixmap...
        cachePainter.drawPixmap(QPoint(radius, radius) + offset, px);
        QPixmapCache::insert(pixmapName, cache);
    }

    QRect targetRect = cache.rect();
    targetRect.setWidth(cache.rect().width() / cache.devicePixelRatioF());
    targetRect.setHeight(cache.rect().height() / cache.devicePixelRatioF());
    targetRect.moveCenter(rect.center());
    p->drawPixmap(targetRect.topLeft() - offset, cache);
}

} // namespace Utils
