/***************************************************************************
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** Copyright (C) 2017 QNX Software Systems. All rights reserved.
** Copyright (C) 2011 - 2012 Research In Motion
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** This file is part of the plugins of the Qt Toolkit.
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** packaging of this file. Please review the following information to
** 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
** Public license version 3 or any later version approved by the KDE Free
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****************************************************************************/

#include "qqnxglobal.h"

#include "qqnxscreeneventthread.h"
#include "qqnxscreeneventhandler.h"

#include <QtCore/QDebug>

#include <errno.h>
#include <unistd.h>

#include <cctype>

#if defined(QQNXSCREENEVENTTHREAD_DEBUG)
#define qScreenEventThreadDebug qDebug
#else
#define qScreenEventThreadDebug QT_NO_QDEBUG_MACRO
#endif

static const int c_screenCode = _PULSE_CODE_MINAVAIL + 0;
static const int c_armCode = _PULSE_CODE_MINAVAIL + 1;
static const int c_quitCode = _PULSE_CODE_MINAVAIL + 2;

#if !defined(screen_register_event)
int screen_register_event(screen_context_t, struct sigevent *event)
{
    return MsgRegisterEvent(event, -1);
}

int screen_unregister_event(struct sigevent *event)
{
    return MsgUnregisterEvent(event);
}
#endif

QQnxScreenEventThread::QQnxScreenEventThread(screen_context_t context)
    : QThread()
    , m_screenContext(context)
{
    m_channelId = ChannelCreate(_NTO_CHF_DISCONNECT | _NTO_CHF_UNBLOCK | _NTO_CHF_PRIVATE);
    if (m_channelId == -1) {
        qFatal("QQnxScreenEventThread: Can't continue without a channel");
    }

    m_connectionId = ConnectAttach(0, 0, m_channelId, _NTO_SIDE_CHANNEL, 0);
    if (m_connectionId == -1) {
        ChannelDestroy(m_channelId);
        qFatal("QQnxScreenEventThread: Can't continue without a channel connection");
    }

    SIGEV_PULSE_INIT(&m_screenEvent, m_connectionId, SIGEV_PULSE_PRIO_INHERIT, c_screenCode, 0);
    if (screen_register_event(m_screenContext, &m_screenEvent) == -1) {
        ConnectDetach(m_connectionId);
        ChannelDestroy(m_channelId);
        qFatal("QQnxScreenEventThread: Can't continue without a registered event");
    }

    screen_notify(m_screenContext, SCREEN_NOTIFY_EVENT, nullptr, &m_screenEvent);
}

QQnxScreenEventThread::~QQnxScreenEventThread()
{
    // block until thread terminates
    shutdown();

    screen_notify(m_screenContext, SCREEN_NOTIFY_EVENT, nullptr, nullptr);
    screen_unregister_event(&m_screenEvent);
    ConnectDetach(m_connectionId);
    ChannelDestroy(m_channelId);
}

void QQnxScreenEventThread::run()
{
    qScreenEventThreadDebug("screen event thread started");

    while (1) {
        struct _pulse msg;
        memset(&msg, 0, sizeof(msg));
        int receiveId = MsgReceive(m_channelId, &msg, sizeof(msg), nullptr);
        if (receiveId == 0 && msg.code == c_quitCode)
            break;
        else if (receiveId == 0)
            handlePulse(msg);
        else if (receiveId > 0)
            qWarning() << "Unexpected message" << msg.code;
        else
            qWarning() << "MsgReceive error" << strerror(errno);
    }

    qScreenEventThreadDebug("screen event thread stopped");
}

void QQnxScreenEventThread::armEventsPending(int count)
{
    MsgSendPulse(m_connectionId, SIGEV_PULSE_PRIO_INHERIT, c_armCode, count);
}

void QQnxScreenEventThread::handleScreenPulse(const struct _pulse &msg)
{
    Q_UNUSED(msg);

    ++m_screenPulsesSinceLastArmPulse;
    if (m_emitNeededOnNextScreenPulse) {
        m_emitNeededOnNextScreenPulse = false;
        Q_EMIT eventsPending();
    }
}

void QQnxScreenEventThread::handleArmPulse(const struct _pulse &msg)
{
    if (msg.value.sival_int == 0 && m_screenPulsesSinceLastArmPulse == 0) {
        m_emitNeededOnNextScreenPulse = true;
    } else {
        m_screenPulsesSinceLastArmPulse = 0;
        m_emitNeededOnNextScreenPulse = false;
        Q_EMIT eventsPending();
    }
}

void QQnxScreenEventThread::handlePulse(const struct _pulse &msg)
{
    if (msg.code == c_screenCode)
        handleScreenPulse(msg);
    else if (msg.code == c_armCode)
        handleArmPulse(msg);
    else
        qWarning() << "Unexpected pulse" << msg.code;
}

void QQnxScreenEventThread::shutdown()
{
    MsgSendPulse(m_connectionId, SIGEV_PULSE_PRIO_INHERIT, c_quitCode, 0);

    qScreenEventThreadDebug("screen event thread shutdown begin");

    // block until thread terminates
    wait();

    qScreenEventThreadDebug("screen event thread shutdown end");
}