pilotclient/src/blackmisc/valueobject.h

/* Copyright (C) 2013
 * swift project Community / Contributors
 *
 * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
 * directory of this distribution and at http://www.swift-project.org/license.html. No part of swift project,
 * including this file, may be copied, modified, propagated, or distributed except according to the terms
 * contained in the LICENSE file.
 */

//! \file

#ifndef BLACKMISC_VALUEOBJECT_H
#define BLACKMISC_VALUEOBJECT_H

#include "dbus.h"
#include "tuple.h"
#include "json.h"
#include "variant.h"
#include <QtDBus/QDBusMetaType>
#include <QString>
#include <QtGlobal>
#include <QDataStream>
#include <QDebug>
#include <QPixmap>
#include <QJsonObject>
#include <QJsonValue>
#include <QJsonValueRef>
#include <type_traits>
#include <iostream>

namespace BlackMisc
{
    // forward declaration
    class CPropertyIndex;
    class CIndexVariantMap;
    class CIcon;

    namespace PhysicalQuantities
    {
        template <class MU, class PQ> class CPhysicalQuantity; // forward declaration

        //! Traits class to test whether a class is a physical quantity class. Useful for enable_if.
        template <class T>
        class IsQuantity
        {
            struct yes { char x; };
            struct no { yes x[2]; };
            template <class MU, class PQ> static yes test(const CPhysicalQuantity<MU, PQ> &);
            static no test(...);

        public:
            //! True if and only if T is derived from CPhysicalQuantity.
            static const bool value = sizeof(test(*(T *)0)) == sizeof(yes);
        };
    }

    /*!
     * Base class for value objects.
     * Public non-virtual interface with protected virtual implementation.
     */
    class CValueObject
    {

        //! Stream << overload to be used in debugging messages
        friend QDebug operator<<(QDebug debug, const CValueObject &uc)
        {
            debug << uc.stringForStreaming();
            return debug;
        }

        //! Operator << based on text stream
        friend QTextStream &operator<<(QTextStream &textStream, const CValueObject &uc)
        {
            textStream << uc.stringForStreaming();
            return textStream;
        }

        //! Operator << when there is no debug stream
        friend QNoDebug operator<<(QNoDebug nodebug, const CValueObject &valueObject)
        {
            Q_UNUSED(valueObject);
            return nodebug;
        }

        //! Operator << for QDataStream
        friend QDataStream &operator<<(QDataStream &stream, const CValueObject &valueObject)
        {
            stream << valueObject.stringForStreaming();
            return stream;
        }

        //! Stream operator << for std::cout
        friend std::ostream &operator<<(std::ostream &ostr, const CValueObject &uc)
        {
            ostr << uc.stringForStreaming().toStdString();
            return ostr;
        }

        //! Unmarshalling operator >>, DBus to object
        friend const QDBusArgument &operator>>(const QDBusArgument &argument, CValueObject &valueObject);

        //! Marshalling operator <<, object to DBus
        friend QDBusArgument &operator<<(QDBusArgument &argument, const CValueObject &valueObject);

        //! Operator == with value map
        friend bool operator==(const CIndexVariantMap &valueMap, const CValueObject &valueObject);

        //! Operator != with value map
        friend bool operator!=(const CIndexVariantMap &valueMap, const CValueObject &valueObject);

        //! Operator == with value map
        friend bool operator==(const CValueObject &valueObject, const CIndexVariantMap &valueMap);

        //! Operator != with value map
        friend bool operator!=(const CValueObject &valueObject, const CIndexVariantMap &valueMap);

        //! Comparison operator to allow valueobjects be used as keys in QMap and std::set.
        template <class T> friend typename std::enable_if < std::is_base_of<CValueObject, T>::value  &&! PhysicalQuantities::IsQuantity<T>::value, bool >::type
        operator<(const T &lhs, const T &rhs)
        {
            const auto &lhsBase = static_cast<const CValueObject &>(lhs);
            const auto &rhsBase = static_cast<const CValueObject &>(rhs);
            return lhsBase.compareImpl(rhsBase) < 0;
        }

        //! Comparison for symmetry with operator<.
        template <class T> friend typename std::enable_if < std::is_base_of<CValueObject, T>::value  &&! PhysicalQuantities::IsQuantity<T>::value, bool >::type
        operator>(const T &lhs, const T &rhs)
        {
            const auto &lhsBase = static_cast<const CValueObject &>(lhs);
            const auto &rhsBase = static_cast<const CValueObject &>(rhs);
            return lhsBase.compareImpl(rhsBase) > 0;
        }

        //! Comparison for symmetry with operator<.
        template <class T> friend typename std::enable_if < std::is_base_of<CValueObject, T>::value  &&! PhysicalQuantities::IsQuantity<T>::value, bool >::type
        operator<=(const T &lhs, const T &rhs)
        {
            const auto &lhsBase = static_cast<const CValueObject &>(lhs);
            const auto &rhsBase = static_cast<const CValueObject &>(rhs);
            return lhsBase.compareImpl(rhsBase) <= 0;
        }

        //! Comparison for symmetry with operator<.
        template <class T> friend typename std::enable_if < std::is_base_of<CValueObject, T>::value  &&! PhysicalQuantities::IsQuantity<T>::value, bool >::type
        operator>=(const T &lhs, const T &rhs)
        {
            const auto &lhsBase = static_cast<const CValueObject &>(lhs);
            const auto &rhsBase = static_cast<const CValueObject &>(rhs);
            return lhsBase.compareImpl(rhsBase) >= 0;
        }

        /*!
         * Compares two instances of related classes
         * and returns an integer less than, equal to, or greater than zero
         * if v1 is less than, equal to, or greater than v2.
         * \return
         * \pre The runtime types of the two objects must be the same or related by inheritance.
         */
        friend int compare(const CValueObject &v1, const CValueObject &v2);

    public:
        //! Base class enums
        enum ColumnIndex
        {
            IndexPixmap,
            IndexIcon,
            IndexString
        };

        //! Virtual destructor
        virtual ~CValueObject() {}

        //! Cast as QString
        QString toQString(bool i18n = false) const;

        //! Cast to pretty-printed QString
        virtual QString toFormattedQString(bool i18n = false) const;

        //! To std string
        std::string toStdString(bool i18n = false) const;

        //! Update by variant map
        int apply(const BlackMisc::CIndexVariantMap &indexMap);

        //! Value hash, allows comparisons between QVariants
        virtual uint getValueHash() const = 0;

        //! Virtual method to return QVariant, used with DBus QVariant lists
        virtual QVariant toQVariant() const = 0;

        //! Virtual method to return CVariant
        virtual CVariant toCVariant() const { return CVariant(this->toQVariant()); }

        //! Contribute to JSON object
        virtual QJsonObject toJson() const { QJsonObject json; return json;}

        //! Initialize from JSON object
        virtual void fromJson(const QJsonObject &json) { Q_UNUSED(json); }

        //! As icon, not implement by all classes
        virtual CIcon toIcon() const;

        //! As pixmap, required for most GUI views
        virtual QPixmap toPixmap() const;

        //! Set property by index
        //! \remarks Intentionally not abstract, avoiding all classes need to implement this method
        virtual void setPropertyByIndex(const QVariant &variant, const CPropertyIndex &index);

        //! Property by index
        //! \remarks Intentionally not abstract, avoiding all classes need to implement this method
        virtual QVariant propertyByIndex(const BlackMisc::CPropertyIndex &index) const;

        //! Property by index as String
        //! Intentionally not abstract, avoiding all classes need to implement this method
        virtual QString propertyByIndexAsString(const CPropertyIndex &index, bool i18n = false) const;

        //! The stored object as CValueObject
        static const CValueObject *fromQVariant(const QVariant &qv);

    protected:
        //! Default constructor
        CValueObject() {}

        //! Copy constructor
        CValueObject(const CValueObject &) {}

        //! Copy assignment operator =
        CValueObject &operator=(const CValueObject &) { return *this; }

        //! String for streaming operators
        virtual QString stringForStreaming() const;

        //! String for QString conversion
        virtual QString convertToQString(bool i18n = false) const = 0;

        //! Returns the Qt meta type ID of this object.
        virtual int getMetaTypeId() const = 0;

        /*!
         * Returns true if this object is an instance of the class with the given meta type ID,
         *        or one of its subclasses.
         * \param metaTypeId
         * \return
         */
        virtual bool isA(int metaTypeId) const { Q_UNUSED(metaTypeId); return false; }

        /*!
         * Compare this value with another value of the same type
         * \param other
         * \return Less than, equal to, or greater than zero if this is
         *         less than, equal to, or greather than other.
         * \pre Other must have the same runtime type as the this object.
         * \remark It is usually safer to use the friend function compare() instead.
         */
        virtual int compareImpl(const CValueObject &other) const = 0;

        //! Marshall to DBus
        virtual void marshallToDbus(QDBusArgument &) const = 0;

        //! Unmarshall from DBus
        virtual void unmarshallFromDbus(const QDBusArgument &) = 0;

        //! Parse from string, e.g. 100km/h
        virtual void parseFromString(const QString &) { qFatal("Not implemented"); }

    };

    /*!
     * Non-member non-friend operator for streaming T objects to QDBusArgument.
     * Needed because we can't rely on the friend operator in some cases due to
     * an unrelated template for streaming Container<T> in QtDBus/qdbusargument.h
     * which matches more types than it can actually handle.
     *
     * <a href="https://dev.vatsim-germany.org/boards/15/topics/26?r=891#message-891">Forum</a>
     * <a href="https://dev.vatsim-germany.org/boards/15/topics/26?r=865#message-865">Forum</a>
     *
     * \param argument
     * \param valueObject
     * \return
     */
    template <class T> typename std::enable_if<std::is_base_of<CValueObject, T>::value, QDBusArgument>::type const &
    operator>>(const QDBusArgument &argument, T &valueObject)
    {
        return argument >> static_cast<CValueObject &>(valueObject);
    }

    /*!
     * Non-member non-friend operator for streaming T objects from QDBusArgument.
     * Needed because we can't rely on the friend operator in some cases due to
     * an unrelated template for streaming Container<T> in QtDBus/qdbusargument.h
     * which matches more types than it can actually handle.
     *
     * <a href="https://dev.vatsim-germany.org/boards/15/topics/26?r=891#message-891">Forum</a>
     * <a href="https://dev.vatsim-germany.org/boards/15/topics/26?r=865#message-865">Forum</a>
     *
     * \param argument
     * \param valueObject
     * \return
     */
    template <class T> typename std::enable_if<std::is_base_of<CValueObject, T>::value, QDBusArgument>::type &
    operator<<(QDBusArgument &argument, const T &valueObject)
    {
        return argument << static_cast<CValueObject const &>(valueObject);
    }

    //! Non member, non friend operator >> for JSON
    inline const QJsonObject &operator>>(const QJsonObject &json, CValueObject &valueObject)
    {
        valueObject.fromJson(json);
        return json;
    }

    //! Non member, non friend operator >> for JSON
    inline const QJsonValue &operator>>(const QJsonValue &json, CValueObject &valueObject)
    {
        valueObject.fromJson(json.toObject());
        return json;
    }

    //! Non member, non friend operator >> for JSON
    inline const QJsonValueRef &operator>>(const QJsonValueRef &json, CValueObject &valueObject)
    {
        valueObject.fromJson(json.toObject());
        return json;
    }

    //! Non member, non friend operator << for JSON
    inline QJsonArray &operator<<(QJsonArray &json, const CValueObject &value)
    {
        json.append(value.toJson());
        return json;
    }

    /*!
     * Non member, non friend operator << for JSON
     * \param json
     * \param value as pair name/value
     * \return
     */
    template <class T> typename std::enable_if<std::is_base_of<CValueObject, T>::value, QJsonObject>::type &
    operator<<(QJsonObject &json, const std::pair<QString, T> &value)
    {
        json.insert(value.first, QJsonValue(value.second.toJson()));
        return json;
    }

    //! Allow comparison with QVariant, e.g. QVariant == CFrequency ?
    template <class T> typename std::enable_if<std::is_base_of<CValueObject, T>::value, bool>::type
    operator==(const QVariant &variant, const T &valueObject)
    {
        if (!variant.canConvert<T>()) return false;
        T vuc = variant.value<T>();
        return vuc == valueObject;
    }

    //! Allow comparison with QVariant, e.g. QVariant != CFrequency ?
    template <class T> typename std::enable_if<std::is_base_of<CValueObject, T>::value, bool>::type
    operator!=(const QVariant &variant, const T &valueObject)
    {
        return !(variant == valueObject);
    }

    //! Allow comparison with QVariant, e.g. QVariant == CFrequency ?
    template <class T> typename std::enable_if<std::is_base_of<CValueObject, T>::value, bool>::type
    operator==(const T &valueObject, const QVariant &variant)
    {
        return variant == valueObject;
    }

    //! Allow comparison with QVariant, e.g. QVariant != CFrequency ?
    template <class T> typename std::enable_if<std::is_base_of<CValueObject, T>::value, bool>::type
    operator!=(const T &valueObject, const QVariant &variant)
    {
        return variant != valueObject;
    }

    //! qHash overload, needed for storing CValueObject in a QSet.
    inline uint qHash(const BlackMisc::CValueObject &value, uint seed = 0)
    {
        return ::qHash(value.getValueHash(), seed);
    }

    // Needed so that our qHash overload doesn't hide the qHash overloads in the global namespace.
    // This will be safe as long as no global qHash has the same signature as ours.
    // Alternative would be to qualify all our invokations of the global qHash as ::qHash.
    using ::qHash;

} // namespace

#endif // guard