/******************************************************************************
 * Copyright (C) 2019 Kitsune Ral <kitsune-ral@users.sf.net>
 *
 * 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) any later version.
 *
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#pragma once

#include "util.h"

#include <QtCore/QPointer>

namespace QMatrixClient {
    namespace _impl {
        template <typename SenderT, typename SignalT,
                  typename ContextT, typename... ArgTs>
        inline QMetaObject::Connection connectUntil(
                SenderT* sender, SignalT signal, ContextT* context,
                std::function<bool(ArgTs...)> slot, Qt::ConnectionType connType)
        {
            // See https://bugreports.qt.io/browse/QTBUG-60339
#if QT_VERSION < QT_VERSION_CHECK(5, 10, 0)
            auto pc = std::make_shared<QMetaObject::Connection>();
#else
            auto pc = std::make_unique<QMetaObject::Connection>();
#endif
            auto& c = *pc; // Resolve a reference before pc is moved to lambda
            c = QObject::connect(sender, signal, context,
                [pc=std::move(pc),slot] (ArgTs... args) {
                    Q_ASSERT(*pc); // If it's been triggered, it should exist
                    if (slot(std::forward<ArgTs>(args)...))
                        QObject::disconnect(*pc);
            }, connType);
            return c;
        }
    }

    template <typename SenderT, typename SignalT,
              typename ContextT, typename FunctorT>
    inline auto connectUntil(SenderT* sender, SignalT signal, ContextT* context,
                             const FunctorT& slot,
                             Qt::ConnectionType connType = Qt::AutoConnection)
    {
        return _impl::connectUntil(sender, signal, context,
                typename function_traits<FunctorT>::function_type(slot),
                connType);
    }

    /** Create a single-shot connection that triggers on the signal and
     * then self-disconnects
     *
     * Only supports DirectConnection type.
     */
    template <typename SenderT, typename SignalT,
              typename ReceiverT, typename SlotT>
    inline auto connectSingleShot(SenderT* sender, SignalT signal,
                                  ReceiverT* receiver, SlotT slot)
    {
        QMetaObject::Connection connection;
        connection = QObject::connect(sender, signal, receiver, slot,
                                      Qt::DirectConnection);
        Q_ASSERT(connection);
        QObject::connect(sender, signal, receiver,
                         [connection] { QObject::disconnect(connection); },
                         Qt::DirectConnection);
        return connection;
    }

    /** A guard pointer that disconnects an interested object upon destruction
     * It's almost QPointer<> except that you have to initialise it with one
     * more additional parameter - a pointer to a QObject that will be
     * disconnected from signals of the underlying pointer upon the guard's
     * destruction.
     */
    template <typename T>
    class ConnectionsGuard : public QPointer<T>
    {
        public:
            ConnectionsGuard(T* publisher, QObject* subscriber)
                : QPointer<T>(publisher), subscriber(subscriber)
            { }
            ~ConnectionsGuard()
            {
                if (*this)
                    (*this)->disconnect(subscriber);
            }
            ConnectionsGuard(ConnectionsGuard&&) = default;
            ConnectionsGuard& operator=(ConnectionsGuard&&) = default;
            Q_DISABLE_COPY(ConnectionsGuard)
            using QPointer<T>::operator=;

        private:
            QObject* subscriber;
    };
}