/****************************************************************************
 *
 *   (c) 2009-2016 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
 *
 * QGroundControl is licensed according to the terms in the file
 * COPYING.md in the root of the source code directory.
 *
 ****************************************************************************/


/**
 * @file
 *   @brief Implementation of class MAVLinkProtocol
 *   @author Lorenz Meier <mail@qgroundcontrol.org>
 */

#include <inttypes.h>
#include <iostream>

#include <QDebug>
#include <QTime>
#include <QApplication>
#include <QSettings>
#include <QStandardPaths>
#include <QtEndian>
#include <QMetaType>
#include <QDir>
#include <QFileInfo>

#include "MAVLinkProtocol.h"
#include "UASInterface.h"
#include "UASInterface.h"
#include "UAS.h"
#include "LinkManager.h"
#include "QGCMAVLink.h"
#include "QGC.h"
#include "QGCApplication.h"
#include "QGCLoggingCategory.h"
#include "MultiVehicleManager.h"
#include "SettingsManager.h"

Q_DECLARE_METATYPE(mavlink_message_t)

QGC_LOGGING_CATEGORY(MAVLinkProtocolLog, "MAVLinkProtocolLog")

const char* MAVLinkProtocol::_tempLogFileTemplate = "FlightDataXXXXXX"; ///< Template for temporary log file
const char* MAVLinkProtocol::_logFileExtension = "mavlink";             ///< Extension for log files

/**
 * The default constructor will create a new MAVLink object sending heartbeats at
 * the MAVLINK_HEARTBEAT_DEFAULT_RATE to all connected links.
 */
MAVLinkProtocol::MAVLinkProtocol(QGCApplication* app, QGCToolbox* toolbox)
    : QGCTool(app, toolbox)
    , m_enable_version_check(true)
    , versionMismatchIgnore(false)
    , systemId(255)
    , _current_version(100)
    , _radio_version_mismatch_count(0)
    , _logSuspendError(false)
    , _logSuspendReplay(false)
    , _vehicleWasArmed(false)
    , _tempLogFile(QString("%2.%3").arg(_tempLogFileTemplate).arg(_logFileExtension))
    , _linkMgr(NULL)
    , _multiVehicleManager(NULL)
{
    memset(&totalReceiveCounter, 0, sizeof(totalReceiveCounter));
    memset(&totalLossCounter, 0, sizeof(totalLossCounter));
    memset(&totalErrorCounter, 0, sizeof(totalErrorCounter));
    memset(&currReceiveCounter, 0, sizeof(currReceiveCounter));
    memset(&currLossCounter, 0, sizeof(currLossCounter));
}

MAVLinkProtocol::~MAVLinkProtocol()
{
    storeSettings();
    _closeLogFile();
}

void MAVLinkProtocol::setVersion(unsigned version)
{
    QList<LinkInterface*> links = _linkMgr->links();

    for (int i = 0; i < links.length(); i++) {
        mavlink_status_t* mavlinkStatus = mavlink_get_channel_status(links[i]->mavlinkChannel());

        // Set flags for version
        if (version < 200) {
            mavlinkStatus->flags |= MAVLINK_STATUS_FLAG_OUT_MAVLINK1;
        } else {
            mavlinkStatus->flags &= ~MAVLINK_STATUS_FLAG_OUT_MAVLINK1;
        }
    }

    _current_version = version;
}

void MAVLinkProtocol::setToolbox(QGCToolbox *toolbox)
{
   QGCTool::setToolbox(toolbox);

   _linkMgr =               _toolbox->linkManager();
   _multiVehicleManager =   _toolbox->multiVehicleManager();

   qRegisterMetaType<mavlink_message_t>("mavlink_message_t");

   loadSettings();

   // All the *Counter variables are not initialized here, as they should be initialized
   // on a per-link basis before those links are used. @see resetMetadataForLink().

   // Initialize the list for tracking dropped messages to invalid.
   for (int i = 0; i < 256; i++)
   {
       for (int j = 0; j < 256; j++)
       {
           lastIndex[i][j] = -1;
       }
   }

   connect(this, &MAVLinkProtocol::protocolStatusMessage,   _app, &QGCApplication::criticalMessageBoxOnMainThread);
   connect(this, &MAVLinkProtocol::saveTelemetryLog,        _app, &QGCApplication::saveTelemetryLogOnMainThread);
   connect(this, &MAVLinkProtocol::checkTelemetrySavePath,  _app, &QGCApplication::checkTelemetrySavePathOnMainThread);

   connect(_multiVehicleManager, &MultiVehicleManager::vehicleAdded, this, &MAVLinkProtocol::_vehicleCountChanged);
   connect(_multiVehicleManager, &MultiVehicleManager::vehicleRemoved, this, &MAVLinkProtocol::_vehicleCountChanged);

   emit versionCheckChanged(m_enable_version_check);
}

void MAVLinkProtocol::loadSettings()
{
    // Load defaults from settings
    QSettings settings;
    settings.beginGroup("QGC_MAVLINK_PROTOCOL");
    enableVersionCheck(settings.value("VERSION_CHECK_ENABLED", m_enable_version_check).toBool());

    // Only set system id if it was valid
    int temp = settings.value("GCS_SYSTEM_ID", systemId).toInt();
    if (temp > 0 && temp < 256)
    {
        systemId = temp;
    }
}

void MAVLinkProtocol::storeSettings()
{
    // Store settings
    QSettings settings;
    settings.beginGroup("QGC_MAVLINK_PROTOCOL");
    settings.setValue("VERSION_CHECK_ENABLED", m_enable_version_check);
    settings.setValue("GCS_SYSTEM_ID", systemId);
    // Parameter interface settings
}

void MAVLinkProtocol::resetMetadataForLink(LinkInterface *link)
{
    int channel = link->mavlinkChannel();
    totalReceiveCounter[channel] = 0;
    totalLossCounter[channel] = 0;
    totalErrorCounter[channel] = 0;
    currReceiveCounter[channel] = 0;
    currLossCounter[channel] = 0;
    link->setDecodedFirstMavlinkPacket(false);
}

/**
 * This method parses all incoming bytes and constructs a MAVLink packet.
 * It can handle multiple links in parallel, as each link has it's own buffer/
 * parsing state machine.
 * @param link The interface to read from
 * @see LinkInterface
 **/
void MAVLinkProtocol::receiveBytes(LinkInterface* link, QByteArray b)
{
    // Since receiveBytes signals cross threads we can end up with signals in the queue
    // that come through after the link is disconnected. For these we just drop the data
    // since the link is closed.
    if (!_linkMgr->containsLink(link)) {
        return;
    }

//    receiveMutex.lock();
    mavlink_message_t message;
    mavlink_status_t status;

    int mavlinkChannel = link->mavlinkChannel();

    static int nonmavlinkCount = 0;
    static bool checkedUserNonMavlink = false;
    static bool warnedUserNonMavlink = false;

    for (int position = 0; position < b.size(); position++) {
        unsigned int decodeState = mavlink_parse_char(mavlinkChannel, (uint8_t)(b[position]), &message, &status);

        if (decodeState == 0 && !link->decodedFirstMavlinkPacket())
        {
            nonmavlinkCount++;
            if (nonmavlinkCount > 1000 && !warnedUserNonMavlink)
            {
                // 500 bytes with no mavlink message. Are we connected to a mavlink capable device?
                if (!checkedUserNonMavlink)
                {
                    link->requestReset();
                    checkedUserNonMavlink = true;
                }
                else
                {
                    warnedUserNonMavlink = true;
                    // Disconnect the link since its some other device and
                    // QGC clinging on to it and feeding it data might have unintended
                    // side effects (e.g. if its a modem)
                    qDebug() << "disconnected link" << link->getName() << "as it contained no MAVLink data";
                    QMetaObject::invokeMethod(_linkMgr, "disconnectLink", Q_ARG( LinkInterface*, link ) );
                    return;
                }
            }
        }
        if (decodeState == 1)
        {
            if (!link->decodedFirstMavlinkPacket()) {
                link->setDecodedFirstMavlinkPacket(true);
                mavlink_status_t* mavlinkStatus = mavlink_get_channel_status(mavlinkChannel);
                if (!(mavlinkStatus->flags & MAVLINK_STATUS_FLAG_IN_MAVLINK1) && (mavlinkStatus->flags & MAVLINK_STATUS_FLAG_OUT_MAVLINK1)) {
                    qDebug() << "Switching outbound to mavlink 2.0 due to incoming mavlink 2.0 packet:" << mavlinkStatus << mavlinkChannel << mavlinkStatus->flags;
                    mavlinkStatus->flags &= ~MAVLINK_STATUS_FLAG_OUT_MAVLINK1;

                    // Set all links to v2
                    setVersion(200);
                }
            }

            // Log data
            if (!_logSuspendError && !_logSuspendReplay && _tempLogFile.isOpen()) {
                uint8_t buf[MAVLINK_MAX_PACKET_LEN+sizeof(quint64)];

                // Write the uint64 time in microseconds in big endian format before the message.
                // This timestamp is saved in UTC time. We are only saving in ms precision because
                // getting more than this isn't possible with Qt without a ton of extra code.
                quint64 time = (quint64)QDateTime::currentMSecsSinceEpoch() * 1000;
                qToBigEndian(time, buf);

                // Then write the message to the buffer
                int len = mavlink_msg_to_send_buffer(buf + sizeof(quint64), &message);

                // Determine how many bytes were written by adding the timestamp size to the message size
                len += sizeof(quint64);

                // Now write this timestamp/message pair to the log.
                QByteArray b((const char*)buf, len);
                if(_tempLogFile.write(b) != len)
                {
                    // If there's an error logging data, raise an alert and stop logging.
                    emit protocolStatusMessage(tr("MAVLink Protocol"), tr("MAVLink Logging failed. Could not write to file %1, logging disabled.").arg(_tempLogFile.fileName()));
                    _stopLogging();
                    _logSuspendError = true;
                }

                // Check for the vehicle arming going by. This is used to trigger log save.
                if (!_vehicleWasArmed && message.msgid == MAVLINK_MSG_ID_HEARTBEAT) {
                    mavlink_heartbeat_t state;
                    mavlink_msg_heartbeat_decode(&message, &state);
                    if (state.base_mode & MAV_MODE_FLAG_DECODE_POSITION_SAFETY) {
                        _vehicleWasArmed = true;
                    }
                }
            }

            if (message.msgid == MAVLINK_MSG_ID_HEARTBEAT) {
                // Start loggin on first heartbeat
                _startLogging();
                mavlink_heartbeat_t heartbeat;
                mavlink_msg_heartbeat_decode(&message, &heartbeat);
                emit vehicleHeartbeatInfo(link, message.sysid, message.compid, heartbeat.mavlink_version, heartbeat.autopilot, heartbeat.type);
            }

            // Detect if we are talking to an old radio not supporting v2
            mavlink_status_t* mavlinkStatus = mavlink_get_channel_status(mavlinkChannel);
            if (message.msgid == MAVLINK_MSG_ID_RADIO_STATUS) {
                if ((mavlinkStatus->flags & MAVLINK_STATUS_FLAG_IN_MAVLINK1)
                && !(mavlinkStatus->flags & MAVLINK_STATUS_FLAG_OUT_MAVLINK1)) {

                    _radio_version_mismatch_count++;
                }
            }

            if (_radio_version_mismatch_count == 5) {
                // Warn the user if the radio continues to send v1 while the link uses v2
                emit protocolStatusMessage(tr("MAVLink Protocol"), tr("Detected radio still using MAVLink v1.0 on a link with MAVLink v2.0 enabled. Please upgrade the radio firmware."));
                // Ensure the warning can't get stuck
                _radio_version_mismatch_count++;
                // Flick link back to v1
                qDebug() << "Switching outbound to mavlink 1.0 due to incoming mavlink 1.0 packet:" << mavlinkStatus << mavlinkChannel << mavlinkStatus->flags;
                mavlinkStatus->flags |= MAVLINK_STATUS_FLAG_OUT_MAVLINK1;
            }

            // Increase receive counter
            totalReceiveCounter[mavlinkChannel]++;
            currReceiveCounter[mavlinkChannel]++;

            // Determine what the next expected sequence number is, accounting for
            // never having seen a message for this system/component pair.
            int lastSeq = lastIndex[message.sysid][message.compid];
            int expectedSeq = (lastSeq == -1) ? message.seq : (lastSeq + 1);

            // And if we didn't encounter that sequence number, record the error
            if (message.seq != expectedSeq)
            {

                // Determine how many messages were skipped
                int lostMessages = message.seq - expectedSeq;

                // Out of order messages or wraparound can cause this, but we just ignore these conditions for simplicity
                if (lostMessages < 0)
                {
                    lostMessages = 0;
                }

                // And log how many were lost for all time and just this timestep
                totalLossCounter[mavlinkChannel] += lostMessages;
                currLossCounter[mavlinkChannel] += lostMessages;
            }

            // And update the last sequence number for this system/component pair
            lastIndex[message.sysid][message.compid] = expectedSeq;

            // Update on every 32th packet
            if ((totalReceiveCounter[mavlinkChannel] & 0x1F) == 0)
            {
                // Calculate new loss ratio
                // Receive loss
                float receiveLossPercent = (double)currLossCounter[mavlinkChannel]/(double)(currReceiveCounter[mavlinkChannel]+currLossCounter[mavlinkChannel]);
                receiveLossPercent *= 100.0f;
                currLossCounter[mavlinkChannel] = 0;
                currReceiveCounter[mavlinkChannel] = 0;
                emit receiveLossPercentChanged(message.sysid, receiveLossPercent);
                emit receiveLossTotalChanged(message.sysid, totalLossCounter[mavlinkChannel]);
            }

            // The packet is emitted as a whole, as it is only 255 - 261 bytes short
            // kind of inefficient, but no issue for a groundstation pc.
            // It buys as reentrancy for the whole code over all threads
            emit messageReceived(link, message);
        }
    }
}

/**
 * @return The name of this protocol
 **/
QString MAVLinkProtocol::getName()
{
    return QString(tr("MAVLink protocol"));
}

/** @return System id of this application */
int MAVLinkProtocol::getSystemId()
{
    return systemId;
}

void MAVLinkProtocol::setSystemId(int id)
{
    systemId = id;
}

/** @return Component id of this application */
int MAVLinkProtocol::getComponentId()
{
    return 0;
}

void MAVLinkProtocol::enableVersionCheck(bool enabled)
{
    m_enable_version_check = enabled;
    emit versionCheckChanged(enabled);
}

void MAVLinkProtocol::_vehicleCountChanged(void)
{
    int count = _multiVehicleManager->vehicles()->count();
    if (count == 0) {
        // Last vehicle is gone, close out logging
        _stopLogging();
        _radio_version_mismatch_count = 0;
    }
}

/// @brief Closes the log file if it is open
bool MAVLinkProtocol::_closeLogFile(void)
{
    if (_tempLogFile.isOpen()) {
        if (_tempLogFile.size() == 0) {
            // Don't save zero byte files
            _tempLogFile.remove();
            return false;
        } else {
            _tempLogFile.flush();
            _tempLogFile.close();
            return true;
        }
    }
    return false;
}

void MAVLinkProtocol::_startLogging(void)
{
    //-- Are we supposed to write logs?
    if (qgcApp()->runningUnitTests()) {
        return;
    }
#ifdef __mobile__
    //-- Mobile build don't write to /tmp unless told to do so
    if (!_app->toolbox()->settingsManager()->appSettings()->telemetrySave()->rawValue().toBool()) {
        return;
    }
#endif
    //-- Log is always written to a temp file. If later the user decides they want
    //   it, it's all there for them.
    if (!_tempLogFile.isOpen()) {
        if (!_logSuspendReplay) {
            if (!_tempLogFile.open()) {
                emit protocolStatusMessage(tr("MAVLink Protocol"), tr("Opening Flight Data file for writing failed. "
                                                                      "Unable to write to %1. Please choose a different file location.").arg(_tempLogFile.fileName()));
                _closeLogFile();
                _logSuspendError = true;
                return;
            }

            qDebug() << "Temp log" << _tempLogFile.fileName();
            emit checkTelemetrySavePath();

            _logSuspendError = false;
        }
    }
}

void MAVLinkProtocol::_stopLogging(void)
{
    if (_tempLogFile.isOpen()) {
        if (_closeLogFile()) {
            if ((_vehicleWasArmed || _app->toolbox()->settingsManager()->appSettings()->telemetrySaveNotArmed()->rawValue().toBool()) &&
                _app->toolbox()->settingsManager()->appSettings()->telemetrySave()->rawValue().toBool()) {
                emit saveTelemetryLog(_tempLogFile.fileName());
            } else {
                QFile::remove(_tempLogFile.fileName());
            }
        }
    }
    _vehicleWasArmed = false;
}

/// @brief Checks the temp directory for log files which may have been left there.
///         This could happen if QGC crashes without the temp log file being saved.
///         Give the user an option to save these orphaned files.
void MAVLinkProtocol::checkForLostLogFiles(void)
{
    QDir tempDir(QStandardPaths::writableLocation(QStandardPaths::TempLocation));

    QString filter(QString("*.%1").arg(_logFileExtension));
    QFileInfoList fileInfoList = tempDir.entryInfoList(QStringList(filter), QDir::Files);
    qDebug() << "Orphaned log file count" << fileInfoList.count();

    foreach(const QFileInfo fileInfo, fileInfoList) {
        qDebug() << "Orphaned log file" << fileInfo.filePath();
        if (fileInfo.size() == 0) {
            // Delete all zero length files
            QFile::remove(fileInfo.filePath());
            continue;
        }
        emit saveTelemetryLog(fileInfo.filePath());
    }
}

void MAVLinkProtocol::suspendLogForReplay(bool suspend)
{
    _logSuspendReplay = suspend;
}

void MAVLinkProtocol::deleteTempLogFiles(void)
{
    QDir tempDir(QStandardPaths::writableLocation(QStandardPaths::TempLocation));

    QString filter(QString("*.%1").arg(_logFileExtension));
    QFileInfoList fileInfoList = tempDir.entryInfoList(QStringList(filter), QDir::Files);

    foreach(const QFileInfo fileInfo, fileInfoList) {
        QFile::remove(fileInfo.filePath());
    }
}