/*
    MIT License

    Copyright (C) 2019-2021 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in all
    copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    SOFTWARE.
*/

#ifndef KDSINGLEAPPLICATION_LOCALSOCKET_P_H
#define KDSINGLEAPPLICATION_LOCALSOCKET_P_H

#include <QtCore/QObject>
#include <QtCore/QByteArray>
#include <QtCore/QString>

QT_BEGIN_NAMESPACE
class QLockFile;
class QLocalServer;
class QLocalSocket;
class QTimer;
QT_END_NAMESPACE

#include <memory>
#include <vector>

struct QObjectDeleteLater
{
    void operator()(QObject *o) { o->deleteLater(); }
};

class QObjectConnectionHolder
{
    Q_DISABLE_COPY(QObjectConnectionHolder)
    QMetaObject::Connection c;

public:
    QObjectConnectionHolder() {}

    explicit QObjectConnectionHolder(QMetaObject::Connection c)
        : c(std::move(c))
    {
    }

    ~QObjectConnectionHolder()
    {
        QObject::disconnect(c);
    }

    QObjectConnectionHolder(QObjectConnectionHolder &&other) noexcept
        : c(std::exchange(other.c, {}))
    {}

    QObjectConnectionHolder &operator=(QObjectConnectionHolder &&other) noexcept
    {
        QObjectConnectionHolder moved(std::move(other));
        swap(moved);
        return *this;
    }

    void swap(QObjectConnectionHolder &other) noexcept
    {
        using std::swap;
        swap(c, other.c);
    }
};

class KDSingleApplicationLocalSocket : public QObject
{
    Q_OBJECT

public:
    explicit KDSingleApplicationLocalSocket(const QString &name,
                                            QObject *parent = nullptr);
    ~KDSingleApplicationLocalSocket();

    bool isPrimaryInstance() const;

public Q_SLOTS:
    bool sendMessage(const QByteArray &message, int timeout);

Q_SIGNALS:
    void messageReceived(const QByteArray &message);

private:
    void handleNewConnection();
    void readDataFromSecondary();
    bool readDataFromSecondarySocket(QLocalSocket *socket);
    void secondaryDisconnected();
    void secondarySocketDisconnected(QLocalSocket *socket);
    void abortConnectionToSecondary();

    QString m_socketName;

    std::unique_ptr<QLockFile> m_lockFile; // protects m_localServer
    std::unique_ptr<QLocalServer> m_localServer;

    struct Connection {
        explicit Connection(QLocalSocket *s);

        std::unique_ptr<QLocalSocket, QObjectDeleteLater> socket;
        std::unique_ptr<QTimer, QObjectDeleteLater> timeoutTimer;
        QByteArray readData;

        // socket/timeoutTimer are deleted via deleteLater (as we delete them
        // in slots connected to their signals). Before the deleteLater is acted upon,
        // they may emit further signals, triggering logic that it's not supposed
        // to be triggered (as the Connection has already been destroyed).
        // Use this Holder to break the connections.
        QObjectConnectionHolder readDataConnection;
        QObjectConnectionHolder secondaryDisconnectedConnection;
        QObjectConnectionHolder abortConnection;
    };

    std::vector<Connection> m_clients;
};

#endif // KDSINGLEAPPLICATION_LOCALSOCKET_P_H