/*
Copyright (C) 2015 Srivats P.

This file is part of "Ostinato"

This is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>
*/

#include "updater.h"

#include <QCoreApplication>
#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QXmlStreamReader>

extern const char* version;

Updater::Updater()
{
    http_ = new QNetworkAccessManager(this);

#if 1
    // Tests!
    Q_ASSERT(isVersionNewer("1.2.0", "1.1") == true);
    Q_ASSERT(isVersionNewer("1.1", "1") == true);
    Q_ASSERT(isVersionNewer("10.1", "2") == true);
    Q_ASSERT(isVersionNewer("0.10", "0.2") == true);
    Q_ASSERT(isVersionNewer("1.10.1", "1.2.3") == true);
    Q_ASSERT(isVersionNewer("0.7.1", "0.8") == false);
#endif
}

Updater::~Updater()
{
    delete http_;
}

void Updater::checkForNewVersion()
{
    QNetworkRequest request(QUrl("http://update.ostinato.org/update/pad.xml"));

    //reqHdr.setHeader("Host", host);
    request.setHeader(QNetworkRequest::UserAgentHeader, userAgent());

    connect(http_, SIGNAL(finished(QNetworkReply*)), 
            this, SLOT(parseXml(QNetworkReply*)));

    http_->get(request);

    QList<QByteArray> headers = request.rawHeaderList();
    foreach(QByteArray hdr, headers ) {
        QByteArray val = request.rawHeader(hdr);
        qDebug("Updater: %s: %s", qPrintable(QString(hdr)),
                qPrintable(QString(val)));
    }
}

void Updater::parseXml(QNetworkReply *reply) 
{
    QXmlStreamReader xml;
    QString newVersion;

    if (reply->error()) {
        qDebug("Updater: %s", qPrintable(reply->errorString()));
        goto _exit;
    }

    xml.setDevice(reply);

    while (!xml.atEnd()) {
        xml.readNext();
        if (xml.isStartElement() && (xml.name() == "Program_Version"))
            newVersion = xml.readElementText();
    }

    qDebug("Updater: latest version = %s", qPrintable(newVersion));
    if (!newVersion.isEmpty() && isVersionNewer(newVersion, QString(version)))
        emit newVersionAvailable(newVersion);

    emit latestVersion(newVersion);

_exit:
    // Job done, time to self-destruct
    deleteLater();
}

bool Updater::isVersionNewer(QString newVersion, QString curVersion)
{
    QStringList curVer = QString(curVersion).split('.');
    QStringList newVer = QString(newVersion).split('.');

    for (int i = 0; i < qMin(curVer.size(), newVer.size()); i++) {
        bool isOk;
        uint n = newVer.at(i).toUInt(&isOk);
        uint c = curVer.at(i).toUInt(&isOk);
        if (n > c)
            return true;
        else if (n < c)
            return false;
    }
    
    if (newVer.size() > curVer.size())
        return true;

    return false;
}

QString Updater::userAgent()
{
    QString ua = QString("Mozilla/5.0 (%1) %2/%3 (Qt/%6)")
                    .arg(sysInfo())
                    .arg(QCoreApplication::instance()->applicationName())
                    .arg(version)
                    .arg(qVersion());

    return ua;
}

QString Updater::sysInfo()
{
#if QT_VERSION >= 0x050400
    return QSysInfo::prettyProductName();
#else
#if defined(Q_OS_WIN32)
    return QString("Windows/0x%1").arg(QSysInfo::WindowsVersion, 0, 16);
#elif defined(Q_OS_LINUX)
    return QString("Linux");
#elif defined(Q_OS_MAC)
    return QString("MacOSX/0x%1").arg(QSysInfo::MacintoshVersion, 0, 16);
#elif defined(Q_OS_BSD4)
    return QString("BSD");
#elif defined(Q_OS_UNIX)
    return QString("Unix");
#else
    return QString("Unknown");
#endif
#endif
}