/*  This file is part of the KDE project
    Copyright (C) 2006-2007 Matthias Kretz <kretz@kde.org>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) version 3, or any
    later version accepted by the membership of KDE e.V. (or its
    successor approved by the membership of KDE e.V.), Nokia Corporation 
    (or its successors, if any) and the KDE Free Qt Foundation, which shall
    act as a proxy defined in Section 6 of version 3 of the license.

    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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public 
    License along with this library.  If not, see <http://www.gnu.org/licenses/>.

*/

#ifndef PHONONDEFS_P_H
#define PHONONDEFS_P_H

#include <QtCore/QMetaType>
#include "medianode_p.h"

#define K_D(Class) Class##Private *const d = k_func()

#define PHONON_CONCAT_HELPER_INTERNAL(x, y) x ## y
#define PHONON_CONCAT_HELPER(x, y) PHONON_CONCAT_HELPER_INTERNAL(x, y)

#define PHONON_PRIVATECLASS \
protected: \
    virtual bool aboutToDeleteBackendObject(); \
    virtual void createBackendObject(); \
    /**
     * \internal
     * After construction of the Iface object this method is called
     * throughout the complete class hierarchy in order to set up the
     * properties that were already set on the public interface.
     *
     * An example implementation could look like this:
     * \code
     * ParentClassPrivate::setupBackendObject();
     * m_iface->setPropertyA(d->propertyA);
     * m_iface->setPropertyB(d->propertyB);
     * \endcode
     */ \
    void setupBackendObject();

#define PHONON_PRIVATEABSTRACTCLASS \
protected: \
    virtual bool aboutToDeleteBackendObject(); \
    /**
     * \internal
     * After construction of the Iface object this method is called
     * throughout the complete class hierarchy in order to set up the
     * properties that were already set on the public interface.
     *
     * An example implementation could look like this:
     * \code
     * ParentClassPrivate::setupBackendObject();
     * m_iface->setPropertyA(d->propertyA);
     * m_iface->setPropertyB(d->propertyB);
     * \endcode
     */ \
    void setupBackendObject();

#define PHONON_ABSTRACTBASE_IMPL \
PHONON_CLASSNAME::PHONON_CLASSNAME(PHONON_CONCAT_HELPER(PHONON_CLASSNAME, Private) &dd, QObject *parent) \
    : QObject(parent), \
    MediaNode(dd) \
{ \
}

#define PHONON_OBJECT_IMPL \
PHONON_CLASSNAME::PHONON_CLASSNAME(QObject *parent) \
    : QObject(parent), \
    MediaNode(*new PHONON_CONCAT_HELPER(PHONON_CLASSNAME, Private)()) \
{ \
} \
void PHONON_CONCAT_HELPER(PHONON_CLASSNAME, Private)::createBackendObject() \
{ \
    if (m_backendObject) \
        return; \
    Q_Q(PHONON_CLASSNAME); \
    m_backendObject = Factory::PHONON_CONCAT_HELPER(create, PHONON_CLASSNAME)(q); \
    if (m_backendObject) { \
        setupBackendObject(); \
    } \
}

#define PHONON_HEIR_IMPL(parentclass) \
PHONON_CLASSNAME::PHONON_CLASSNAME(QObject *parent) \
    : parentclass(*new PHONON_CONCAT_HELPER(PHONON_CLASSNAME, Private), parent) \
{ \
} \
void PHONON_CONCAT_HELPER(PHONON_CLASSNAME, Private)::createBackendObject() \
{ \
    if (m_backendObject) \
        return; \
    Q_Q(PHONON_CLASSNAME); \
    m_backendObject = Factory::PHONON_CONCAT_HELPER(create, PHONON_CLASSNAME)(q); \
    if (m_backendObject) { \
        setupBackendObject(); \
    } \
}

#define BACKEND_GET(returnType, returnVar, methodName) \
QMetaObject::invokeMethod(d->m_backendObject, methodName, Qt::DirectConnection, Q_RETURN_ARG(returnType, returnVar))
#define BACKEND_GET1(returnType, returnVar, methodName, varType1, var1) \
QMetaObject::invokeMethod(d->m_backendObject, methodName, Qt::DirectConnection, Q_RETURN_ARG(returnType, returnVar), Q_ARG(varType1, var1))
#define BACKEND_GET2(returnType, returnVar, methodName, varType1, var1, varType2, var2) \
QMetaObject::invokeMethod(d->m_backendObject, methodName, Qt::DirectConnection, Q_RETURN_ARG(returnType, returnVar), Q_ARG(varType1, var1), Q_ARG(varType2, var2))
#define BACKEND_CALL(methodName) \
QMetaObject::invokeMethod(d->m_backendObject, methodName, Qt::DirectConnection)
#define BACKEND_CALL1(methodName, varType1, var1) \
QMetaObject::invokeMethod(d->m_backendObject, methodName, Qt::DirectConnection, Q_ARG(varType1, var1))
#define BACKEND_CALL2(methodName, varType1, var1, varType2, var2) \
QMetaObject::invokeMethod(d->m_backendObject, methodName, Qt::DirectConnection, Q_ARG(varType1, var1), Q_ARG(varType2, var2))

#define pBACKEND_GET(returnType, returnVar, methodName) \
QMetaObject::invokeMethod(m_backendObject, methodName, Qt::DirectConnection, Q_RETURN_ARG(returnType, returnVar))
#define pBACKEND_GET1(returnType, returnVar, methodName, varType1, var1) \
QMetaObject::invokeMethod(m_backendObject, methodName, Qt::DirectConnection, Q_RETURN_ARG(returnType, returnVar), Q_ARG(varType1, var1))
#define pBACKEND_GET2(returnType, returnVar, methodName, varType1, var1, varType2, var2) \
QMetaObject::invokeMethod(m_backendObject, methodName, Qt::DirectConnection, Q_RETURN_ARG(returnType, returnVar), Q_ARG(varType1, var1), Q_ARG(varType2, var2))
#define pBACKEND_CALL(methodName) \
QMetaObject::invokeMethod(m_backendObject, methodName, Qt::DirectConnection)
#define pBACKEND_CALL1(methodName, varType1, var1) \
QMetaObject::invokeMethod(m_backendObject, methodName, Qt::DirectConnection, Q_ARG(varType1, var1))
#define pBACKEND_CALL2(methodName, varType1, var1, varType2, var2) \
QMetaObject::invokeMethod(m_backendObject, methodName, Qt::DirectConnection, Q_ARG(varType1, var1), Q_ARG(varType2, var2))

QT_BEGIN_NAMESPACE

namespace Phonon
{
    namespace
    {
        class NoIface;

        /// All template arguments are valid
        template<typename T> struct IsValid { enum { Result = true }; };
        /// except NoIface
        template<> struct IsValid<NoIface> { enum { Result = false }; };

        template<class T> inline T my_cast(QObject *o) { return qobject_cast<T>(o); }
        template<class T> inline T my_cast(const QObject *o) { return qobject_cast<T>(o); }

        template<> inline NoIface *my_cast<NoIface *>(QObject *) { return 0; }
        template<> inline NoIface *my_cast<NoIface *>(const QObject *) { return 0; }
    } // anonymous namespace

    /**
     * \internal
     *
     * \brief Helper class to cast the backend object to the correct version of the interface.
     *
     * Additions to the backend interfaces cannot be done by adding virtual methods as that would
     * break the binary interface. So the old class is renamed and a new class with the old name
     * inheriting the old class is added, containing all the new virtual methods.
     * Example:
     * \code
       class FooInterface
       {
       public:
           virtual ~FooInterface() {}
           virtual oldMethod() = 0;
       };
       Q_DECLARE_INTERFACE(FooInterface, "FooInterface0.phonon.kde.org")
     * \endcode
     * becomes
     * \code
       class FooInterface0
       {
       public:
           virtual ~FooInterface0() {}
           virtual oldMethod() = 0;
       };
       class FooInterface : public FooInterface0
       {
       public:
           virtual newMethod() = 0;
       };
       Q_DECLARE_INTERFACE(FooInterface0, "FooInterface0.phonon.kde.org")
       Q_DECLARE_INTERFACE(FooInterface,  "FooInterface1.phonon.kde.org")
     * \endcode
     *
     * With this, backends compiled against the old header can be qobject_casted to FooInterface0,
     * but not to FooInterface. On the other hand backends compiled against the new header (they first
     * need to implement newMethod) can only be qobject_casted to FooInterface but not to
     * FooInterface0. (The qobject_cast relies on the string in Q_DECLARE_INTERFACE and not the
     * class name which is why it behaves that way.)
     *
     * Now, in order to call oldMethod, the code needs to try to cast to both FooInterface and
     * FooInterface0 (new backends will work with the former, old backends with the latter) and then
     * if one of them in non-zero call oldMethod on it.
     *
     * To call newMethod only a cast to FooInterface needs to be done.
     *
     * The Iface class does all this for you for up to three (for now) interface revisions. Just
     * create an object like this:
     * \code
       Iface<FooInterface0, FooInterface> iface0(d);
       if (iface0) {
           iface0->oldMethod();
       }
       Iface<FooInterface> iface(d);
       if (iface) {
           iface->newMethod();
       }
     * \endcode
     *
     * This becomes a bit more convenient if you add macros like this:
     * \code
       #define IFACES1 FooInterface
       #define IFACES0 FooInterface0, IFACES1
     * \endcode
     * which you can use like this:
     * \code
       Iface<IFACES0> iface0(d);
       if (iface0) {
           iface0->oldMethod();
       }
       Iface<IFACES1> iface(d);
       if (iface) {
           iface->newMethod();
       }
     * \endcode
     * With the next revision you can then change the macros to
     * \code
       #define IFACES2 FooInterface
       #define IFACES1 FooInterface1, IFACES2
       #define IFACES0 FooInterface0, IFACES1
     * \endcode
     *
     * \author Matthias Kretz <kretz@kde.org>
     */
    template<class T0, class T1 = NoIface, class T2 = NoIface>
    class Iface
    {
    public:
        static inline T0 *cast(MediaNodePrivate *const d)
        {
            if (IsValid<T1>::Result) {
                T0 *ret;
                if (IsValid<T2>::Result) {
                    ret = reinterpret_cast<T0 *>(my_cast<T2 *>(d->m_backendObject));
                    if (ret) return ret;
                }
                ret = reinterpret_cast<T0 *>(my_cast<T1 *>(d->m_backendObject));
                if (ret) return ret;
            }
            return qobject_cast<T0 *>(d->m_backendObject);
        }

        static inline const T0 *cast(const MediaNodePrivate *const d)
        {
            if (IsValid<T1>::Result) {
                const T0 *ret;
                if (IsValid<T2>::Result) {
                    ret = reinterpret_cast<const T0 *>(my_cast<T2 *>(d->m_backendObject));
                    if (ret) return ret;
                }
                ret = reinterpret_cast<const T0 *>(my_cast<T1 *>(d->m_backendObject));
                if (ret) return ret;
            }
            return qobject_cast<T0 *>(d->m_backendObject);
        }

        inline Iface(MediaNodePrivate *const d) : iface(cast(d)) {}
        inline operator       T0 *()       { return iface; }
        inline operator const T0 *() const { return iface; }
        inline       T0 *operator->()       { Q_ASSERT(iface); return iface; }
        inline const T0 *operator->() const { Q_ASSERT(iface); return iface; }
    private:
        T0 *const iface;
    };

    template<class T0, class T1 = NoIface, class T2 = NoIface>
    class ConstIface
    {
    public:
        inline ConstIface(const MediaNodePrivate *const d) : iface(Iface<T0, T1, T2>::cast(d)) {}
        inline operator const T0 *() const { return iface; }
        inline const T0 *operator->() const { Q_ASSERT(iface); return iface; }
    private:
        const T0 *const iface;
    };
} // namespace Phonon

QT_END_NAMESPACE

#define INTERFACE_CALL(function) \
Iface<PHONON_INTERFACENAME >::cast(d)->function

#define pINTERFACE_CALL(function) \
Iface<PHONON_INTERFACENAME >::cast(this)->function

#define PHONON_GETTER(rettype, name, retdefault) \
rettype PHONON_CLASSNAME::name() const \
{ \
    const PHONON_CONCAT_HELPER(PHONON_CLASSNAME, Private) *d = k_func(); \
    if (!d->m_backendObject) \
        return retdefault; \
    rettype ret; \
    BACKEND_GET(rettype, ret, #name); \
    return ret; \
}

#define PHONON_INTERFACE_GETTER(rettype, name, retdefault) \
rettype PHONON_CLASSNAME::name() const \
{ \
    const PHONON_CONCAT_HELPER(PHONON_CLASSNAME, Private) *d = k_func(); \
    if (!d->m_backendObject) \
        return retdefault; \
    return Iface<PHONON_INTERFACENAME >::cast(d)->name(); \
}

#define PHONON_GETTER1(rettype, name, retdefault, argtype1, argvar1) \
rettype PHONON_CLASSNAME::name(argtype1 argvar1) const \
{ \
    const PHONON_CONCAT_HELPER(PHONON_CLASSNAME, Private) *d = k_func(); \
    if (!d->m_backendObject) \
        return retdefault; \
    rettype ret; \
    BACKEND_GET1(rettype, ret, #name, const QObject *, argvar1->k_ptr->backendObject()); \
    return ret; \
}

#define PHONON_INTERFACE_GETTER1(rettype, name, retdefault, argtype1, argvar1) \
rettype PHONON_CLASSNAME::name(argtype1 argvar1) const \
{ \
    const PHONON_CONCAT_HELPER(PHONON_CLASSNAME, Private) *d = k_func(); \
    if (!d->m_backendObject) \
        return retdefault; \
    return Iface<PHONON_INTERFACENAME >::cast(d)->name(argvar1->k_ptr->backendObject()); \
}

#define PHONON_SETTER(functionname, privatevar, argtype1) \
void PHONON_CLASSNAME::functionname(argtype1 x) \
{ \
    PHONON_CONCAT_HELPER(PHONON_CLASSNAME, Private) *d = k_func(); \
    d->privatevar = x; \
    if (k_ptr->backendObject()) { \
        BACKEND_CALL1(#functionname, argtype1, x); \
    } \
}

#define PHONON_INTERFACE_SETTER(functionname, privatevar, argtype1) \
void PHONON_CLASSNAME::functionname(argtype1 x) \
{ \
    PHONON_CONCAT_HELPER(PHONON_CLASSNAME, Private) *d = k_func(); \
    d->privatevar = x; \
    if (k_ptr->backendObject()) { \
        Iface<PHONON_INTERFACENAME >::cast(d)->functionname(x); \
    } \
}

#ifndef METATYPE_QLIST_INT_DEFINED
#define METATYPE_QLIST_INT_DEFINED
// Want this exactly once, see phonondefs_p.h kcm/outputdevicechoice.cpp
Q_DECLARE_METATYPE(QList<int>)
#endif

#endif // PHONONDEFS_P_H
