/****************************************************************************
**
** Copyright (C) 1992-2007 Trolltech ASA. All rights reserved.
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
** this file.  Please review the following information to ensure GNU
** General Public Licensing requirements will be met:
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** If you are unsure which license is appropriate for your use, please
** review the following information:
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** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
****************************************************************************/

#include "qfontcombobox.h"

#ifndef QT_NO_FONTCOMBOBOX

#include <qstringlistmodel.h>
#include <qitemdelegate.h>
#include <qlistview.h>
#include <qpainter.h>
#include <qevent.h>
#include <private/qcombobox_p.h>
#include <qdebug.h>

static QFontDatabase::WritingSystem writingSystemForFont(const QFont &font, bool *hasLatin)
{
    *hasLatin = true;

    QList<QFontDatabase::WritingSystem> writingSystems = QFontDatabase().writingSystems(font.family());
//     qDebug() << font.family() << writingSystems;

    // this just confuses the algorithm below. Vietnamese is Latin with lots of special chars
    writingSystems.removeAll(QFontDatabase::Vietnamese);

    QFontDatabase::WritingSystem system = QFontDatabase::Any;

    if (!writingSystems.contains(QFontDatabase::Latin)) {
        *hasLatin = false;
        // we need to show something
        if (writingSystems.count())
            system = writingSystems.last();
    } else {
        writingSystems.removeAll(QFontDatabase::Latin);
    }

    if (writingSystems.isEmpty())
        return system;

    if (writingSystems.count() == 1 && writingSystems.at(0) > QFontDatabase::Cyrillic) {
        system = writingSystems.at(0);
        return system;
    }

    if (writingSystems.count() <= 2
        && writingSystems.last() > QFontDatabase::Armenian
        && writingSystems.last() < QFontDatabase::Vietnamese) {
        system = writingSystems.last();
        return system;
    }

    if (writingSystems.count() <= 5
        && writingSystems.last() >= QFontDatabase::SimplifiedChinese
        && writingSystems.last() <= QFontDatabase::Korean)
        system = writingSystems.last();

    return system;
}

class QFontFamilyDelegate : public QAbstractItemDelegate
{
    Q_OBJECT
public:
    explicit QFontFamilyDelegate(QObject *parent);

    // painting
    void paint(QPainter *painter,
               const QStyleOptionViewItem &option,
               const QModelIndex &index) const;

    QSize sizeHint(const QStyleOptionViewItem &option,
                   const QModelIndex &index) const;

    QIcon truetype;
    QIcon bitmap;
    QFontDatabase::WritingSystem writingSystem;
};

QFontFamilyDelegate::QFontFamilyDelegate(QObject *parent)
    : QAbstractItemDelegate(parent)
{
    truetype = QIcon(QLatin1String(":/trolltech/styles/commonstyle/images/fonttruetype-16.png"));
    bitmap = QIcon(QLatin1String(":/trolltech/styles/commonstyle/images/fontbitmap-16.png"));
    writingSystem = QFontDatabase::Any;
}

void QFontFamilyDelegate::paint(QPainter *painter,
                                const QStyleOptionViewItem &option,
                                const QModelIndex &index) const
{
    QString text = index.data(Qt::DisplayRole).toString();
    QFont font(option.font);
    font.setPointSize(font.pointSize() * 3 / 2);
    QFont font2 = font;
    font2.setFamily(text);

    bool hasLatin;
    QFontDatabase::WritingSystem system = writingSystemForFont(font2, &hasLatin);
    if (hasLatin)
        font = font2;

    QRect r = option.rect;

    if (option.state & QStyle::State_Selected) {
        painter->save();
        painter->setBrush(option.palette.highlight());
        painter->setPen(Qt::NoPen);
        painter->drawRect(option.rect);
        painter->setPen(QPen(option.palette.highlightedText(), 0));
    }

    const QIcon *icon = &bitmap;
    if (QFontDatabase().isSmoothlyScalable(text)) {
        icon = &truetype;
    }
    QSize actualSize = icon->actualSize(r.size());

    icon->paint(painter, r, Qt::AlignLeft|Qt::AlignVCenter);
    if (option.direction == Qt::RightToLeft)
        r.setRight(r.right() - actualSize.width() - 4);
    else
        r.setLeft(r.left() + actualSize.width() + 4);

    QFont old = painter->font();
    painter->setFont(font);
    painter->drawText(r, Qt::AlignVCenter|Qt::AlignLeading|Qt::TextSingleLine, text);

    if (writingSystem != QFontDatabase::Any)
        system = writingSystem;

    if (system != QFontDatabase::Any) {
        int w = painter->fontMetrics().width(text + QLatin1String("  "));
        painter->setFont(font2);
        QString sample = QFontDatabase().writingSystemSample(system);
        if (option.direction == Qt::RightToLeft)
            r.setRight(r.right() - w);
        else
            r.setLeft(r.left() + w);
        painter->drawText(r, Qt::AlignVCenter|Qt::AlignLeading|Qt::TextSingleLine, sample);
    }
    painter->setFont(old);

    if (option.state & QStyle::State_Selected)
        painter->restore();

}

QSize QFontFamilyDelegate::sizeHint(const QStyleOptionViewItem &option,
                                    const QModelIndex &index) const
{
    QString text = index.data(Qt::DisplayRole).toString();
    QFont font(option.font);
//     font.setFamily(text);
    font.setPointSize(font.pointSize() * 3/2);
    QFontMetrics fontMetrics(font);
    return QSize(fontMetrics.width(text), fontMetrics.lineSpacing());
}


class QFontComboBoxPrivate : public QComboBoxPrivate
{
public:
    inline QFontComboBoxPrivate() { filters = QFontComboBox::AllFonts; }

    QFontComboBox::FontFilters filters;
    QFont currentFont;

    void _q_updateModel();
    void _q_currentChanged(const QString &);

    Q_DECLARE_PUBLIC(QFontComboBox)
};


void QFontComboBoxPrivate::_q_updateModel()
{
    Q_Q(QFontComboBox);
    const int scalableMask = (QFontComboBox::ScalableFonts | QFontComboBox::NonScalableFonts);
    const int spacingMask = (QFontComboBox::ProportionalFonts | QFontComboBox::MonospacedFonts);

    QStringListModel *m = qobject_cast<QStringListModel *>(q->model());
    if (!m)
        return;
    QFontFamilyDelegate *delegate = qobject_cast<QFontFamilyDelegate *>(q->view()->itemDelegate());
    QFontDatabase::WritingSystem system = delegate ? delegate->writingSystem : QFontDatabase::Any;

    QFontDatabase fdb;
    QStringList list = fdb.families(system);

    if (filters != QFontComboBox::AllFonts) {
        QStringList result;
        for (int i = 0; i < list.size(); ++i) {
            if ((filters & scalableMask) && (filters & scalableMask) != scalableMask) {
                if (bool(filters & QFontComboBox::ScalableFonts) != fdb.isSmoothlyScalable(list.at(i)))
                    continue;
            }
            if ((filters & spacingMask) && (filters & spacingMask) != spacingMask) {
                if (bool(filters & QFontComboBox::MonospacedFonts) != fdb.isFixedPitch(list.at(i)))
                    continue;
            }
            result += list.at(i);
        }
        list = result;
    }
    m->setStringList(list);
    QFontInfo fi(currentFont);
    q->setCurrentIndex(m->stringList().indexOf(fi.family()));
}


void QFontComboBoxPrivate::_q_currentChanged(const QString &text)
{
    Q_Q(QFontComboBox);

    currentFont = QFont(text);
    emit q->currentFontChanged(currentFont);
}

/*!
    \class QFontComboBox
    \brief The QFontComboBox widget is a combobox that lets the user
    select a font family.

    \since 4.2
    \ingroup basic
    \ingroup text

    The combobox is populated with an alphabetized list of font
    family names, such as Arial, Helvetica, and Times New Roman.
    Family names are displayed using the actual font when possible.
    For fonts such as Symbol, where the name is not representable in
    the font itself, a sample of the font is displayed next to the
    family name.

    QFontComboBox is often used in toolbars, in conjunction with a
    QComboBox for controlling the font size and two \l{QToolButton}s
    for bold and italic.

    When the user selects a new font, the currentFontChanged() signal
    is emitted in addition to currentIndexChanged().

    Call setWritingSystem() to tell QFontComboBox to show only fonts
    that support a given writing system, and setFontFilters() to
    filter out certain types of fonts as e.g. non scalable fonts or
    monospaced fonts.

    \image windowsxp-fontcombobox.png Screenshot of QFontComboBox on Windows XP

    \sa QComboBox, QFont, QFontInfo, QFontMetrics, QFontDatabase, {Character Map Example}
*/

/*!
    \fn void QFontComboBox::setWritingSystem(QFontDatabase::WritingSystem script)
*/

/*!
    \fn void QFontComboBox::setCurrentFont(const QFont &font);
*/

/*!
    Constructs a font combobox with the given \a parent.
*/
QFontComboBox::QFontComboBox(QWidget *parent)
    : QComboBox(*new QFontComboBoxPrivate, parent)
{
    Q_D(QFontComboBox);
    d->currentFont = font();
    setEditable(true);

    QStringListModel *m = new QStringListModel(this);
    setModel(m);
    setItemDelegate(new QFontFamilyDelegate(this));
    QListView *lview = qobject_cast<QListView*>(view());
    if (lview)
        lview->setUniformItemSizes(true);
    setWritingSystem(QFontDatabase::Any);

    connect(this, SIGNAL(currentIndexChanged(QString)),
            this, SLOT(_q_currentChanged(QString)));

    // qfontdatabase.cpp
    extern QObject *qt_fontdatabase_private();
    connect(qt_fontdatabase_private(), SIGNAL(fontDatabaseChanged()),
            this, SLOT(_q_updateModel()));
}


/*!
    Destroys the combobox.
*/
QFontComboBox::~QFontComboBox()
{
}

/*!
    \property QFontComboBox::writingSystem
    \brief the writing system that serves as a filter for the combobox

    If \a script is QFontDatabase::Any (the default), all fonts are
    listed.

    \sa fontFilters
*/

void QFontComboBox::setWritingSystem(QFontDatabase::WritingSystem script)
{
    Q_D(QFontComboBox);
    QFontFamilyDelegate *delegate = qobject_cast<QFontFamilyDelegate *>(view()->itemDelegate());
    if (delegate)
        delegate->writingSystem = script;
    d->_q_updateModel();
}

QFontDatabase::WritingSystem QFontComboBox::writingSystem() const
{
    QFontFamilyDelegate *delegate = qobject_cast<QFontFamilyDelegate *>(view()->itemDelegate());
    if (delegate)
        return delegate->writingSystem;
    return QFontDatabase::Any;
}


/*!
  \enum QFontComboBox::FontFilter

  This enum can be used to only show certain types of fonts in the font combo box.

  \value AllFonts Show all fonts
  \value ScalableFonts Only show scalable fonts
  \value NonScalableFonts Only show non scalable fonts
  \value MonospacedFonts Only show monospaced fonts
  \value ProportionalFonts Only show proportional fonts
*/

/*!
    \property QFontComboBox::fontFilters
    \brief the filter for the combobox

    By default, all fonts are listed.

    \sa writingSystem
*/
void QFontComboBox::setFontFilters(FontFilters filters)
{
    Q_D(QFontComboBox);
    d->filters = filters;
    d->_q_updateModel();
}

QFontComboBox::FontFilters QFontComboBox::fontFilters() const
{
    Q_D(const QFontComboBox);
    return d->filters;
}

/*!
    \property QFontComboBox::currentFont
    \brief the currently selected font

    \sa currentFontChanged(), currentIndex, currentText
*/
QFont QFontComboBox::currentFont() const
{
    Q_D(const QFontComboBox);
    return d->currentFont;
}

void QFontComboBox::setCurrentFont(const QFont &font)
{
    Q_D(QFontComboBox);
    d->currentFont = font;
    d->_q_updateModel();
}

/*!
    \fn QFontComboBox::currentFontChanged(const QFont &font)

    This signal is emitted whenever the current font changes, with
    the new \a font.

    \sa currentFont
*/

/*!
    \reimp
*/
bool QFontComboBox::event(QEvent *e)
{
    if (e->type() == QEvent::Resize) {
        QListView *lview = qobject_cast<QListView*>(view());
        if (lview)
            lview->window()->setFixedWidth(width() * 5 / 3);
    }
    return QComboBox::event(e);
}

/*!
    \reimp
*/
QSize QFontComboBox::sizeHint() const
{
    QSize sz = QComboBox::sizeHint();
    QFontMetrics fm(font());
    sz.setWidth(fm.width(QLatin1Char('m'))*14);
    return sz;
}

#include "qfontcombobox.moc"
#include "moc_qfontcombobox.cpp"

#endif // QT_NO_FONTCOMBOBOX
