/*
 * barrier -- mouse and keyboard sharing utility
 * Copyright (C) 2014-2016 Symless Ltd.
 *
 * This package is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * found in the file LICENSE that should have accompanied this file.
 *
 * This package 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 "ZeroconfService.h"

#include "MainWindow.h"
#include "ZeroconfRegister.h"
#include "ZeroconfBrowser.h"

#include <QtNetwork>
#include <QMessageBox>
#define _MSL_STDINT_H
#include <stdint.h>
#include <dns_sd.h>

#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#else
#include <stdlib.h>
#endif

static const QStringList preferedIPAddress(
                QStringList() <<
                "192.168." <<
                "10." <<
                "172.");

const char* ZeroconfService:: m_ServerServiceName = "_barrierServerZeroconf._tcp";
const char* ZeroconfService:: m_ClientServiceName = "_barrierClientZeroconf._tcp";

static void silence_avahi_warning()
{
    // the libavahi folks seemingly find Apple's bonjour API distasteful
    // and are quite liberal in taking it out on users...unless we set
    // this environmental variable before calling the avahi library.
    // additionally, Microsoft does not give us a POSIX setenv() so
    // we use their OS-specific API instead
    const char *name  = "AVAHI_COMPAT_NOWARN";
    const char *value = "1";
#ifdef _WIN32
    SetEnvironmentVariable(name, value);
#else
    setenv(name, value, 1);
#endif
}

ZeroconfService::ZeroconfService(MainWindow* mainWindow) :
    m_pMainWindow(mainWindow),
    m_pZeroconfBrowser(0),
    m_pZeroconfRegister(0),
    m_ServiceRegistered(false)
{
    silence_avahi_warning();
    if (m_pMainWindow->barrier_type() == BarrierType::Server) {
        if (registerService(true)) {
            m_pZeroconfBrowser = new ZeroconfBrowser(this);
            connect(m_pZeroconfBrowser, SIGNAL(
                currentRecordsChanged(const QList<ZeroconfRecord>&)),
                this, SLOT(clientDetected(const QList<ZeroconfRecord>&)));
            m_pZeroconfBrowser->browseForType(
                QLatin1String(m_ClientServiceName));
        }
    }
    else {
        m_pZeroconfBrowser = new ZeroconfBrowser(this);
        connect(m_pZeroconfBrowser, SIGNAL(
            currentRecordsChanged(const QList<ZeroconfRecord>&)),
            this, SLOT(serverDetected(const QList<ZeroconfRecord>&)));
        m_pZeroconfBrowser->browseForType(
            QLatin1String(m_ServerServiceName));
    }

    connect(m_pZeroconfBrowser, SIGNAL(error(DNSServiceErrorType)),
        this, SLOT(errorHandle(DNSServiceErrorType)));
}

ZeroconfService::~ZeroconfService()
{
    if (m_pZeroconfBrowser) {
        delete m_pZeroconfBrowser;
    }
    if (m_pZeroconfRegister) {
        delete m_pZeroconfRegister;
    }
}

void ZeroconfService::serverDetected(const QList<ZeroconfRecord>& list)
{
    for (ZeroconfRecord record : list) {
        registerService(false);
        m_pMainWindow->appendLogInfo(tr("zeroconf server detected: %1").arg(
            record.serviceName));
        m_pMainWindow->serverDetected(record.serviceName);
    }
}

void ZeroconfService::clientDetected(const QList<ZeroconfRecord>& list)
{
    for (ZeroconfRecord record : list) {
        m_pMainWindow->appendLogInfo(tr("zeroconf client detected: %1").arg(
            record.serviceName));
        m_pMainWindow->autoAddScreen(record.serviceName);
    }
}

void ZeroconfService::errorHandle(DNSServiceErrorType errorCode)
{
    QMessageBox::critical(0, tr("Zero configuration service"),
        tr("Error code: %1.").arg(errorCode));
}

QString ZeroconfService::getLocalIPAddresses()
{
    QStringList addresses;
    for (const QHostAddress& address : QNetworkInterface::allAddresses()) {
        if (address.protocol() == QAbstractSocket::IPv4Protocol &&
            address != QHostAddress(QHostAddress::LocalHost)) {
            addresses.append(address.toString());
        }
    }

    for (const QString& preferedIP : preferedIPAddress) {
        for (const QString& address : addresses) {
            if (address.startsWith(preferedIP)) {
                return address;
            }
        }
    }

    return "";
}

bool ZeroconfService::registerService(bool server)
{
    bool result = true;

    if (!m_ServiceRegistered) {
        if (!m_zeroconfServer.listen()) {
            QMessageBox::critical(0, tr("Zero configuration service"),
                tr("Unable to start the zeroconf: %1.")
                .arg(m_zeroconfServer.errorString()));
            result = false;
        }
        else {
            m_pZeroconfRegister = new ZeroconfRegister(this);
            if (server) {
                QString localIP = getLocalIPAddresses();
                if (localIP.isEmpty()) {
                    QMessageBox::warning(m_pMainWindow, tr("Barrier"),
                        tr("Failed to get local IP address. "
                           "Please manually type in server address "
                           "on your clients"));
                }
                else {
                    m_pZeroconfRegister->registerService(
                        ZeroconfRecord(tr("%1").arg(localIP),
                        QLatin1String(m_ServerServiceName), QString()),
                        m_zeroconfServer.serverPort());
                }
            }
            else {
                m_pZeroconfRegister->registerService(
                    ZeroconfRecord(tr("%1").arg(m_pMainWindow->getScreenName()),
                    QLatin1String(m_ClientServiceName), QString()),
                    m_zeroconfServer.serverPort());
            }

            m_ServiceRegistered = true;
        }
    }

    return result;
}