/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/
**
** This file is part of the QtQml module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** GNU Lesser General Public License Usage
** 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.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU General
** Public License version 3.0 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 the GNU General
** Public License version 3.0 requirements will be met:
** http://www.gnu.org/copyleft/gpl.html.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms and
** conditions contained in a signed written agreement between you and Nokia.
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qqmlpropertymap.h"

#include <private/qmetaobjectbuilder_p.h>
#include <private/qqmlopenmetaobject_p.h>

#include <QDebug>

QT_BEGIN_NAMESPACE

//QQmlPropertyMapMetaObject lets us listen for changes coming from QML
//so we can emit the changed signal.
class QQmlPropertyMapMetaObject : public QQmlOpenMetaObject
{
public:
    QQmlPropertyMapMetaObject(QQmlPropertyMap *obj, QQmlPropertyMapPrivate *objPriv);

protected:
    virtual void propertyWritten(int index);
    virtual void propertyCreated(int, QMetaPropertyBuilder &);
    virtual int createProperty(const char *, const char *);
private:
    QQmlPropertyMap *map;
    QQmlPropertyMapPrivate *priv;
};

class QQmlPropertyMapPrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QQmlPropertyMap)
public:
    QQmlPropertyMapMetaObject *mo;
    QStringList keys;
    void emitChanged(const QString &key, const QVariant &value);
    bool validKeyName(const QString& name);
};

bool QQmlPropertyMapPrivate::validKeyName(const QString& name)
{
    //The following strings shouldn't be used as property names
    return  name != QLatin1String("keys")
         && name != QLatin1String("valueChanged")
         && name != QLatin1String("QObject")
         && name != QLatin1String("destroyed")
         && name != QLatin1String("deleteLater");
}

void QQmlPropertyMapPrivate::emitChanged(const QString &key, const QVariant &value)
{
    Q_Q(QQmlPropertyMap);
    emit q->valueChanged(key, value);
}

QQmlPropertyMapMetaObject::QQmlPropertyMapMetaObject(QQmlPropertyMap *obj, QQmlPropertyMapPrivate *objPriv) : QQmlOpenMetaObject(obj)
{
    map = obj;
    priv = objPriv;
}

void QQmlPropertyMapMetaObject::propertyWritten(int index)
{
    priv->emitChanged(QString::fromUtf8(name(index)), operator[](index));
}

void QQmlPropertyMapMetaObject::propertyCreated(int, QMetaPropertyBuilder &b)
{
    priv->keys.append(QString::fromUtf8(b.name()));
}

int QQmlPropertyMapMetaObject::createProperty(const char *name, const char *value)
{
    if (!priv->validKeyName(QString::fromUtf8(name)))
        return -1;
    return QQmlOpenMetaObject::createProperty(name, value);
}

/*!
    \class QQmlPropertyMap
    \brief The QQmlPropertyMap class allows you to set key-value pairs that can be used in QML bindings.

    QQmlPropertyMap provides a convenient way to expose domain data to the UI layer.
    The following example shows how you might declare data in C++ and then
    access it in QML.

    In the C++ file:
    \code
    // create our data
    QQmlPropertyMap ownerData;
    ownerData.insert("name", QVariant(QString("John Smith")));
    ownerData.insert("phone", QVariant(QString("555-5555")));

    // expose it to the UI layer
    QQuickView view;
    QQmlContext *ctxt = view.rootContext();
    ctxt->setContextProperty("owner", &ownerData);

    view.setSource(QUrl::fromLocalFile("main.qml"));
    view.show();
    \endcode

    Then, in \c main.qml:
    \code
    Text { text: owner.name + " " + owner.phone }
    \endcode

    The binding is dynamic - whenever a key's value is updated, anything bound to that
    key will be updated as well.

    To detect value changes made in the UI layer you can connect to the valueChanged() signal.
    However, note that valueChanged() is \bold NOT emitted when changes are made by calling insert()
    or clear() - it is only emitted when a value is updated from QML.

    \note It is not possible to remove keys from the map; once a key has been added, you can only
    modify or clear its associated value.
*/

/*!
    Constructs a bindable map with parent object \a parent.
*/
QQmlPropertyMap::QQmlPropertyMap(QObject *parent)
: QObject(*(new QQmlPropertyMapPrivate), parent)
{
    Q_D(QQmlPropertyMap);
    d->mo = new QQmlPropertyMapMetaObject(this, d);
}

/*!
    Destroys the bindable map.
*/
QQmlPropertyMap::~QQmlPropertyMap()
{
}

/*!
    Clears the value (if any) associated with \a key.
*/
void QQmlPropertyMap::clear(const QString &key)
{
    Q_D(QQmlPropertyMap);
    d->mo->setValue(key.toUtf8(), QVariant());
}

/*!
    Returns the value associated with \a key.

    If no value has been set for this key (or if the value has been cleared),
    an invalid QVariant is returned.
*/
QVariant QQmlPropertyMap::value(const QString &key) const
{
    Q_D(const QQmlPropertyMap);
    return d->mo->value(key.toUtf8());
}

/*!
    Sets the value associated with \a key to \a value.

    If the key doesn't exist, it is automatically created.
*/
void QQmlPropertyMap::insert(const QString &key, const QVariant &value)
{
    Q_D(QQmlPropertyMap);

    if (d->validKeyName(key)) {
        d->mo->setValue(key.toUtf8(), value);
    } else {
        qWarning() << "Creating property with name"
                   << key
                   << "is not permitted, conflicts with internal symbols.";
    }
}

/*!
    Returns the list of keys.

    Keys that have been cleared will still appear in this list, even though their
    associated values are invalid QVariants.
*/
QStringList QQmlPropertyMap::keys() const
{
    Q_D(const QQmlPropertyMap);
    return d->keys;
}

/*!
    \overload

    Same as size().
*/
int QQmlPropertyMap::count() const
{
    Q_D(const QQmlPropertyMap);
    return d->keys.count();
}

/*!
    Returns the number of keys in the map.

    \sa isEmpty(), count()
*/
int QQmlPropertyMap::size() const
{
    Q_D(const QQmlPropertyMap);
    return d->keys.size();
}

/*!
    Returns true if the map contains no keys; otherwise returns
    false.

    \sa size()
*/
bool QQmlPropertyMap::isEmpty() const
{
    Q_D(const QQmlPropertyMap);
    return d->keys.isEmpty();
}

/*!
    Returns true if the map contains \a key.

    \sa size()
*/
bool QQmlPropertyMap::contains(const QString &key) const
{
    Q_D(const QQmlPropertyMap);
    return d->keys.contains(key);
}

/*!
    Returns the value associated with the key \a key as a modifiable
    reference.

    If the map contains no item with key \a key, the function inserts
    an invalid QVariant into the map with key \a key, and
    returns a reference to it.

    \sa insert(), value()
*/
QVariant &QQmlPropertyMap::operator[](const QString &key)
{
    //### optimize
    Q_D(QQmlPropertyMap);
    QByteArray utf8key = key.toUtf8();
    if (!d->keys.contains(key))
        insert(key, QVariant());//force creation -- needed below

    return (*(d->mo))[utf8key];
}

/*!
    \overload

    Same as value().
*/
QVariant QQmlPropertyMap::operator[](const QString &key) const
{
    return value(key);
}

/*!
    \fn void QQmlPropertyMap::valueChanged(const QString &key, const QVariant &value)
    This signal is emitted whenever one of the values in the map is changed. \a key
    is the key corresponding to the \a value that was changed.

    \note valueChanged() is \bold NOT emitted when changes are made by calling insert()
    or clear() - it is only emitted when a value is updated from QML.
*/

QT_END_NAMESPACE