/***************************************************************************
**
** Copyright (C) 2017 QNX Software Systems. All rights reserved.
** Copyright (C) 2011 - 2012 Research In Motion
** Contact: https://www.qt.io/licensing/
**
** This file is part of the plugins of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** 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
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#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;

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");
    }

    struct sigevent screenEvent;
    SIGEV_PULSE_INIT(&screenEvent, m_connectionId, SIGEV_PULSE_PRIO_INHERIT, c_screenCode, 0);

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

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

    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");
}