/****************************************************************************
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** Copyright (C) 2016 The Qt Company Ltd.
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** This file is part of the QtDBus module of the Qt Toolkit.
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** ensure the GNU Lesser General Public License version 3 requirements
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** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
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****************************************************************************/

#ifndef QDBUSPENDINGREPLY_H
#define QDBUSPENDINGREPLY_H

#include <QtDBus/qtdbusglobal.h>
#include <QtDBus/qdbusargument.h>
#include <QtDBus/qdbuspendingcall.h>

#ifndef QT_NO_DBUS

QT_BEGIN_NAMESPACE


class Q_DBUS_EXPORT QDBusPendingReplyData: public QDBusPendingCall
{
protected:
    QDBusPendingReplyData();
    ~QDBusPendingReplyData();
    void assign(const QDBusPendingCall &call);
    void assign(const QDBusMessage &message);

    QVariant argumentAt(int index) const;
    void setMetaTypes(int count, const int *metaTypes);
};

namespace QDBusPendingReplyTypes {
    template<int Index,
             typename T1, typename T2, typename T3, typename T4,
             typename T5, typename T6, typename T7, typename T8>
    struct Select
    {
        typedef Select<Index - 1, T2, T3, T4, T5, T6, T7, T8, void> Next;
        typedef typename Next::Type Type;
    };
    template<typename T1, typename T2, typename T3, typename T4,
             typename T5, typename T6, typename T7, typename T8>
    struct Select<0, T1, T2, T3, T4, T5, T6, T7, T8>
    {
        typedef T1 Type;
    };

    template<typename T1> inline int metaTypeFor(T1 * = nullptr)
    { return qMetaTypeId<T1>(); }
    // specialize for QVariant, allowing it to be used in place of QDBusVariant
    template<> inline int metaTypeFor<QVariant>(QVariant *)
    { return qMetaTypeId<QDBusVariant>(); }

    template<typename T1, typename T2, typename T3, typename T4,
             typename T5, typename T6, typename T7, typename T8>
    struct ForEach
    {
        typedef ForEach<T2, T3, T4, T5, T6, T7, T8, void> Next;
        enum { Total = Next::Total + 1 };
        static inline void fillMetaTypes(int *p)
        {
            *p = metaTypeFor<T1>(nullptr);
            Next::fillMetaTypes(++p);
        }
    };
    template<>
    struct ForEach<void, void, void, void,   void, void, void, void>
    {
        enum { Total = 0 };
        static inline void fillMetaTypes(int *)
        { }
    };

    struct TypeIsVoid {};
    template <typename T> struct NotVoid       { typedef T Type; };
    template <>           struct NotVoid<void> { typedef TypeIsVoid Type; };
} // namespace QDBusPendingReplyTypes

template<typename T1 = void, typename T2 = void, typename T3 = void, typename T4 = void,
         typename T5 = void, typename T6 = void, typename T7 = void, typename T8 = void>
class QDBusPendingReply:
#ifdef Q_CLANG_QDOC
    public QDBusPendingCall
#else
    public QDBusPendingReplyData
#endif
{
    typedef QDBusPendingReplyTypes::ForEach<T1, T2, T3, T4, T5, T6, T7, T8> ForEach;
    template<int Index> struct Select :
    QDBusPendingReplyTypes::Select<Index, T1, T2, T3, T4, T5, T6, T7, T8>
    {
    };

public:
    enum { Count = ForEach::Total };

    inline QDBusPendingReply()
    { }
    inline QDBusPendingReply(const QDBusPendingReply &other)
        : QDBusPendingReplyData(other)
    { }
    inline /*implicit*/ QDBusPendingReply(const QDBusPendingCall &call) // required by qdbusxml2cpp-generated code
    { *this = call; }
    inline /*implicit*/ QDBusPendingReply(const QDBusMessage &message)
    { *this = message; }
    inline QDBusPendingReply &operator=(const QDBusPendingReply &other)
    { assign(other); return *this; }
    inline QDBusPendingReply &operator=(const QDBusPendingCall &call)
    { assign(call); return *this; }
    inline QDBusPendingReply &operator=(const QDBusMessage &message)
    { assign(message); return *this; }

    inline int count() const { return Count; }

#if defined(Q_CLANG_QDOC)
    QVariant argumentAt(int index) const;
#else
    using QDBusPendingReplyData::argumentAt;
#endif

#ifndef Q_CLANG_QDOC
    template<int Index> inline
    const typename Select<Index>::Type argumentAt() const
    {
        Q_STATIC_ASSERT_X(Index >= 0 && Index < Count, "Index out of bounds");
        typedef typename Select<Index>::Type ResultType;
        return qdbus_cast<ResultType>(argumentAt(Index), 0);
    }
#endif

#if defined(Q_CLANG_QDOC)
    bool isFinished() const;
    void waitForFinished();

    bool isValid() const;
    bool isError() const;
    QDBusError error() const;
    QDBusMessage reply() const;

    inline T1 value() const;
    inline operator T1() const;
#else
    inline typename Select<0>::Type value() const
    {
        return argumentAt<0>();
    }

    inline operator typename QDBusPendingReplyTypes::NotVoid<T1>::Type() const
    {
        return argumentAt<0>();
    }
#endif

private:
    inline void calculateMetaTypes()
    {
        if (!d) return;
        int typeIds[Count > 0 ? Count : 1]; // use at least one since zero-sized arrays aren't valid
        ForEach::fillMetaTypes(typeIds);
        setMetaTypes(Count, typeIds);
    }

    inline void assign(const QDBusPendingCall &call)
    {
        QDBusPendingReplyData::assign(call);
        calculateMetaTypes();
    }

    inline void assign(const QDBusMessage &message)
    {
        QDBusPendingReplyData::assign(message);
        calculateMetaTypes();
    }
};

QT_END_NAMESPACE

#endif // QT_NO_DBUS
#endif
