/* 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.
 */

#ifndef BLACKSIM_XSWIFTBUS_UTILS_H
#define BLACKSIM_XSWIFTBUS_UTILS_H

#include <XPLM/XPLMDefs.h>
#include <XPLM/XPLMPlugin.h>
#include <XPLM/XPLMProcessing.h>
#include <XPLM/XPLMUtilities.h>
#include <QCoreApplication>
#include <QSharedPointer>
#include <cstring>
#include <cstdio>
#include <cstdlib>
#include <clocale>

/*!
 * \file
 */

/*!
 * Install a Qt message handler which outputs to the X-Plane debug log.
 */
class QXPlaneMessageHandler
{
    static void handler(QtMsgType type, const QMessageLogContext &context, const QString &msg)
    {
        QByteArray localMsg = msg.toLocal8Bit();
        QByteArray file(context.file);
        if (file.isEmpty()) file = "<unknown>";

        int line = context.line;

        char *buffer = new char[64 + localMsg.size() + file.size()];
        switch (type) {
        case QtDebugMsg:
            std::sprintf(buffer, "%s:%d: Debug: %s\n", file.constData(), line, localMsg.constData());
            XPLMDebugString(buffer);
            break;
        case QtInfoMsg:
            std::sprintf(buffer, "%s:%d: Info: %s\n", file.constData(), line, localMsg.constData());
            XPLMDebugString(buffer);
            break;
        case QtWarningMsg:
            std::sprintf(buffer, "%s:%d: Warning: %s\n", file.constData(), line, localMsg.constData());
            XPLMDebugString(buffer);
            break;
        default:
        case QtCriticalMsg:
            std::sprintf(buffer, "%s:%d: Error: %s\n", file.constData(), line, localMsg.constData());
            XPLMDebugString(buffer);
            break;
        case QtFatalMsg:
            std::sprintf(buffer, "%s:%d: Fatal: %s\n", file.constData(), line, localMsg.constData());
            XPLMDebugString(buffer);
            std::abort();
        }
        delete[] buffer;
    }

public:
    /*!
     * Install the handler.
     */
    static void install()
    {
        qInstallMessageHandler(handler);
    }

    //! Not copyable.
    //! @{
    QXPlaneMessageHandler(const QXPlaneMessageHandler &) = delete;
    QXPlaneMessageHandler &operator =(const QXPlaneMessageHandler &) = delete;
    //! @}
};

/*!
 * QApplication subclass used by XSwiftBus.
 *
 * Only one instance of QApplication is allowed per process, so if any other
 * X-Plane plugin, completely unrelated to this pilot client, wants to use the
 * Qt framework, they can simply copy & paste this class into their project
 * and both X-Plane plugins will be able to share a single QApplication safely.
 */
class QSharedApplication : public QCoreApplication
{
    Q_OBJECT

    QWeakPointer<QCoreApplication> m_weakptr;

    QSharedApplication(QSharedPointer<QCoreApplication> &ptr, int &argc, char **argv) : QCoreApplication(argc, argv)
    {
        ptr.reset(this);
        m_weakptr = ptr;
    }

    static char *strdup(const char *s) { auto s2 = static_cast<char *>(std::malloc(std::strlen(s) + 1)); return std::strcpy(s2, s); }

public:
    /*!
     * Returns a shared pointer to the QApplication.
     *
     * The QApplication will not be destroyed while this shared pointer exists.
     */
    static QSharedPointer<QCoreApplication> sharedInstance()
    {
        QSharedPointer<QCoreApplication> ptr;
        if (! instance())
        {
            static int argc = 1;
            static char *argv[] = { strdup("X-Plane") };
      
#ifdef Q_OS_UNIX
            /* Workaround for #362 */
            char* xplocale = setlocale(LC_ALL, nullptr);
#endif
            
            new QSharedApplication(ptr, argc, argv);
            
#ifdef Q_OS_UNIX
            setlocale(LC_ALL, xplocale);
#endif
        }
        if (! instance()->inherits("QSharedApplication"))
        {
            qFatal("There is an unshared QCoreApplication in another plugin");
        }
        return static_cast<QSharedApplication*>(instance())->m_weakptr;
    }
};

/*!
 * Runs the Qt event loop inside the X-Plane event loop.
 */
class QXPlaneEventLoop : public QObject
{
    Q_OBJECT

    QXPlaneEventLoop(QObject *parent) : QObject(parent)
    {
        XPLMRegisterFlightLoopCallback(callback, -1, nullptr);
    }

    ~QXPlaneEventLoop()
    {
        XPLMUnregisterFlightLoopCallback(callback, nullptr);
    }

    static float callback(float, float, int, void *)
    {
        QCoreApplication::processEvents();
        QCoreApplication::sendPostedEvents();
        return -1;
    }

public:
    /*!
     * Registers the X-Plane callback which calls into the Qt event loop,
     * unless one was already registered.
     */
    static void exec()
    {
        if (! QCoreApplication::instance()->findChild<QXPlaneEventLoop *>())
        {
            new QXPlaneEventLoop(QCoreApplication::instance());
        }
    }
};

namespace XSwiftBus
{
    //! Absolute xplane path
    extern QString g_xplanePath;

    //! Platform specific dir separator
    extern QString g_sep;

    //! Init global xplane path
    void initXPlanePath();
}

#endif // guard