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#include "qmlpropertymap.h"
#include <qmlopenmetaobject.h>
#include <QDebug>

QT_BEGIN_NAMESPACE

//QmlPropertyMapMetaObject lets us listen for changes coming from QML
//so we can emit the changed signal.
class QmlPropertyMapMetaObject : public QmlOpenMetaObject
{
public:
    QmlPropertyMapMetaObject(QmlPropertyMap *obj, QmlPropertyMapPrivate *objPriv);

protected:
    virtual void propertyWrite(int index);

private:
    QmlPropertyMap *map;
    QmlPropertyMapPrivate *priv;
};

class QmlPropertyMapPrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QmlPropertyMap)
public:
    QmlPropertyMapMetaObject *mo;
    QStringList keys;
    void emitChanged(const QString &key);
};

void QmlPropertyMapPrivate::emitChanged(const QString &key)
{
    Q_Q(QmlPropertyMap);
    emit q->changed(key);
}

QmlPropertyMapMetaObject::QmlPropertyMapMetaObject(QmlPropertyMap *obj, QmlPropertyMapPrivate *objPriv) : QmlOpenMetaObject(obj)
{
    map = obj;
    priv = objPriv;
}

void QmlPropertyMapMetaObject::propertyWrite(int index)
{
    priv->emitChanged(QString::fromUtf8(name(index)));
}

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

    QmlPropertyMap 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.

    Setup in C++:
    \code
    //create our data
    QmlPropertyMap ownerData;
    ownerData.setValue("name", QVariant(QString("John Smith")));
    ownerData.setValue("phone", QVariant(QString("555-5555")));

    //expose it to the UI layer
    QmlContext *ctxt = view->bindContext();
    ctxt->setProperty("owner", &data);
    \endcode

    Then, in QML:
    \code
    Text { text: owner.name }
    Text { text: 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 changed() signal.
    However, note that changed() is \b NOT emitted when changes are made by calling setValue()
    or clearValue() - it is only emitted when a value is updated from QML.
*/

// is there a more efficient way to store/return keys?
//        (or should we just provide an iterator or something else instead?)
// can we provide a way to clear keys?
// do we want to make any claims regarding key ordering?
// should we have signals for insertion and and deletion -- becoming more model like

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

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

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

/*!
    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 QmlPropertyMap::keys() const
{
    Q_D(const QmlPropertyMap);
    return d->keys;
}

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

QT_END_NAMESPACE