/*
   This file is part of the Nepomuk KDE project.
   Copyright (C) 2007-2008 Sebastian Trueg <trueg@kde.org>

   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 "kratingpainter.h"

#include <QtGui/QPainter>
#include <QtGui/QPixmap>
#include <QtGui/QIcon>
#include <QtCore/QRect>
#include <QtCore/QPoint>

#include <kicon.h>
#include <kiconeffect.h>
#include <kiconloader.h>
#include <kdebug.h>


class KRatingPainter::Private
{
public:
    Private()
        : maxRating(10),
        isEnabled(true),
        bHalfSteps(true),
        alignment(Qt::AlignCenter),
        direction(Qt::LeftToRight),
        spacing(0)
    {
    }

    QPixmap getPixmap(int size);

    int maxRating;
    QIcon icon;
    bool isEnabled;
    bool bHalfSteps;
    Qt::Alignment alignment;
    Qt::LayoutDirection direction;
    int spacing;
};

QPixmap KRatingPainter::Private::getPixmap(int size)
{
    QIcon _icon(icon);
    if (_icon.isNull()) {
        _icon = KIcon("rating");
    }
    return _icon.pixmap(size);
}


KRatingPainter::KRatingPainter()
    : d(new Private())
{
}

KRatingPainter::~KRatingPainter()
{
    delete d;
}

int KRatingPainter::maxRating() const
{
    return d->maxRating;
}

bool KRatingPainter::halfStepsEnabled() const
{
    return d->bHalfSteps;
}

Qt::Alignment KRatingPainter::alignment() const
{
    return d->alignment;
}

Qt::LayoutDirection KRatingPainter::layoutDirection() const
{
    return d->direction;
}

QIcon KRatingPainter::icon() const
{
    return d->icon;
}

bool KRatingPainter::isEnabled() const
{
    return d->isEnabled;
}

int KRatingPainter::spacing() const
{
    return d->spacing;
}

void KRatingPainter::setMaxRating(int max)
{
    d->maxRating = max;
}

void KRatingPainter::setHalfStepsEnabled(bool enabled)
{
    d->bHalfSteps = enabled;
}

void KRatingPainter::setAlignment(Qt::Alignment align)
{
    d->alignment = align;
}

void KRatingPainter::setLayoutDirection(Qt::LayoutDirection direction)
{
    d->direction = direction;
}


void KRatingPainter::setIcon(const QIcon &icon)
{
    d->icon = icon;
}

void KRatingPainter::setEnabled(bool enabled)
{
    d->isEnabled = enabled;
}

void KRatingPainter::setSpacing(int s)
{
    d->spacing = qMax(0, s);
}

void KRatingPainter::paint(QPainter* painter, const QRect &rect, int rating, int hoverRating) const
{
    rating = qMin(rating, d->maxRating);
    hoverRating = qMin(hoverRating, d->maxRating);

    int numUsedStars = (d->bHalfSteps ? d->maxRating / 2 : d->maxRating);

    if ( hoverRating > 0 && hoverRating < rating ) {
        int tmp = hoverRating;
        hoverRating = rating;
        rating = tmp;
    }

    int usedSpacing = d->spacing;

    // get the rating pixmaps
    int maxHSizeOnePix = ((rect.width() - (numUsedStars - 1) * usedSpacing ) / numUsedStars);
    QPixmap ratingPix = d->getPixmap(qMin(rect.height(), maxHSizeOnePix));

    QPixmap disabledRatingPix = KIconEffect::apply(ratingPix, KIconEffect::ToGray, 1.0, QColor(), QColor(), false);
    QPixmap hoverPix;

    // if we are disabled we become gray and more transparent
    if ( !d->isEnabled ) {
        ratingPix = disabledRatingPix;
        KIconEffect::semiTransparent( disabledRatingPix );
    }

    bool half = (d->bHalfSteps && (rating % 2));
    int numRatingStars = (d->bHalfSteps ? rating / 2 : rating);

    int numHoverStars = 0;
    bool halfHover = false;
    if (hoverRating > 0 && rating != hoverRating && d->isEnabled) {
        numHoverStars = d->bHalfSteps ? hoverRating / 2 : hoverRating;
        halfHover = d->bHalfSteps && (hoverRating % 2);
        hoverPix = KIconEffect::apply(ratingPix, KIconEffect::ToGray, 0.5, QColor(), QColor(), false);
    }

    if (d->alignment & Qt::AlignJustify) {
        int w = rect.width();
        w -= numUsedStars * ratingPix.width();
        usedSpacing = w / (numUsedStars - 1);
    }

    int ratingAreaWidth = ratingPix.width()*numUsedStars + usedSpacing*(numUsedStars-1);

    int i = 0;
    int x = rect.x();
    if (d->alignment & Qt::AlignRight) {
        x += ( rect.width() - ratingAreaWidth);
    } else if (d->alignment & Qt::AlignHCenter) {
        x += ((rect.width() - ratingAreaWidth) / 2);
    }

    int xInc = ratingPix.width() + usedSpacing;
    if (d->direction == Qt::RightToLeft) {
        x = (rect.width() - ratingPix.width() - x);
        xInc = -xInc;
    }

    int y = rect.y();
    if (d->alignment & Qt::AlignVCenter) {
        y += (rect.height() / 2 - ratingPix.height() / 2);
    } else if (d->alignment & Qt::AlignBottom ) {
        y += (rect.height() - ratingPix.height() );
    }
    for(; i < numRatingStars; ++i) {
        painter->drawPixmap(x, y, ratingPix);
        x += xInc;
    }
    if (half) {
        painter->drawPixmap(
            x, y, ratingPix.width()/2, ratingPix.height(),
            d->direction == Qt::RightToLeft ? (numHoverStars > 0 ? hoverPix : disabledRatingPix) : ratingPix,
            0, 0, ratingPix.width()/2, ratingPix.height()
        );
        painter->drawPixmap(
            x + ratingPix.width() / 2, y, ratingPix.width() / 2, ratingPix.height(),
            d->direction == Qt::RightToLeft ? ratingPix : (numHoverStars > 0 ? hoverPix : disabledRatingPix),
            ratingPix.width() / 2, 0, ratingPix.width() / 2, ratingPix.height()
        );
        x += xInc;
        ++i;
    }
    for(; i < numHoverStars; ++i ) {
        painter->drawPixmap( x, y, hoverPix );
        x += xInc;
    }
    if( halfHover ) {
        painter->drawPixmap(
            x, y, ratingPix.width()/2, ratingPix.height(),
            d->direction == Qt::RightToLeft ? disabledRatingPix : hoverPix,
            0, 0, ratingPix.width()/2, ratingPix.height()
        );
        painter->drawPixmap(
            x + ratingPix.width() / 2, y, ratingPix.width() / 2, ratingPix.height(),
            d->direction == Qt::RightToLeft ? hoverPix : disabledRatingPix,
            ratingPix.width() / 2, 0, ratingPix.width() / 2, ratingPix.height()
        );
        x += xInc;
        ++i;
    }
    for(; i < numUsedStars; ++i) {
        painter->drawPixmap(x, y, disabledRatingPix);
        x += xInc;
    }
}

int KRatingPainter::ratingFromPosition(const QRect &rect, const QPoint &pos) const
{
    int usedSpacing = d->spacing;
    int numUsedStars = (d->bHalfSteps ? d->maxRating / 2 : d->maxRating);
    int maxHSizeOnePix = ((rect.width() - (numUsedStars - 1) * usedSpacing) / numUsedStars);
    QPixmap ratingPix = d->getPixmap(qMin(rect.height(), maxHSizeOnePix));

    int ratingAreaWidth = ratingPix.width()*numUsedStars + usedSpacing*(numUsedStars-1);

    QRect usedRect(rect);
    if (d->alignment & Qt::AlignRight ) {
        usedRect.setLeft(rect.right() - ratingAreaWidth);
    } else if (d->alignment & Qt::AlignHCenter) {
        int x = (rect.width() - ratingAreaWidth) / 2;
        usedRect.setLeft(rect.left() + x);
        usedRect.setRight(rect.right() - x);
    } else {
        // d->alignment & Qt::AlignLeft
        usedRect.setRight(rect.left() + ratingAreaWidth - 1);
    }

    if (d->alignment & Qt::AlignBottom) {
        usedRect.setTop(rect.bottom() - ratingPix.height() + 1);
    } else if (d->alignment & Qt::AlignVCenter) {
        int x = ( rect.height() - ratingPix.height() )/2;
        usedRect.setTop( rect.top() + x );
        usedRect.setBottom( rect.bottom() - x );
    } else {
        // d->alignment & Qt::AlignTop
        usedRect.setBottom(rect.top() + ratingPix.height() - 1);
    }

    if (usedRect.contains(pos)) {
        int x = 0;
        if (d->direction == Qt::RightToLeft) {
            x = usedRect.right() - pos.x();
        } else {
            x = pos.x() - usedRect.left();
        }

        double one = ( double )usedRect.width() / ( double )d->maxRating;

        // kDebug() << "rating:" << ( int )( ( double )x/one + 0.5 );

        return ( int )( ( double )x/one + 0.5 );
    }
    return -1;
}

void KRatingPainter::paintRating(QPainter *painter, const QRect &rect, Qt::Alignment align, int rating, int hoverRating)
{
    KRatingPainter rp;
    rp.setAlignment(align);
    rp.setLayoutDirection(painter->layoutDirection());
    rp.paint(painter, rect, rating, hoverRating);
}

int KRatingPainter::getRatingFromPosition(const QRect &rect, Qt::Alignment align, Qt::LayoutDirection direction, const QPoint &pos)
{
    KRatingPainter rp;
    rp.setAlignment(align);
    rp.setLayoutDirection(direction);
    return rp.ratingFromPosition(rect, pos);
}