/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
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** This file is part of the QtNetwork module of the Qt Toolkit.
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** General Public License version 3 as published by the Free Software
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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
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****************************************************************************/

#include <winsock2.h>

#include "qhostinfo_p.h"
#include <ws2tcpip.h>
#include <private/qsystemlibrary_p.h>
#include <qmutex.h>
#include <qbasicatomic.h>
#include <qurl.h>

QT_BEGIN_NAMESPACE

//#define QHOSTINFO_DEBUG

//###
#define QT_SOCKLEN_T int
#ifndef NI_MAXHOST // already defined to 1025 in ws2tcpip.h?
#define NI_MAXHOST 1024
#endif

static void translateWSAError(int error, QHostInfo *results)
{
    switch (error) {
    case WSAHOST_NOT_FOUND: //authoritative not found
    case WSATRY_AGAIN: //non authoritative not found
    case WSANO_DATA: //valid name, no associated address
        results->setError(QHostInfo::HostNotFound);
        results->setErrorString(QHostInfoAgent::tr("Host not found"));
        return;
    default:
        results->setError(QHostInfo::UnknownError);
        results->setErrorString(QHostInfoAgent::tr("Unknown error (%1)").arg(error));
        return;
    }
}

QHostInfo QHostInfoAgent::fromName(const QString &hostName)
{
    QSysInfo::machineHostName();        // this initializes ws2_32.dll

    QHostInfo results;

#if defined(QHOSTINFO_DEBUG)
    qDebug("QHostInfoAgent::fromName(): looking up \"%s\" (IPv6 support is %s)",
           hostName.toLatin1().constData(),
           (getaddrinfo && freeaddrinfo) ? "enabled" : "disabled");
#endif

    QHostAddress address;
    if (address.setAddress(hostName)) {
        // Reverse lookup
        sockaddr_in sa4;
        sockaddr_in6 sa6;
        sockaddr *sa;
        QT_SOCKLEN_T saSize;
        if (address.protocol() == QAbstractSocket::IPv4Protocol) {
            sa = reinterpret_cast<sockaddr *>(&sa4);
            saSize = sizeof(sa4);
            memset(&sa4, 0, sizeof(sa4));
            sa4.sin_family = AF_INET;
            sa4.sin_addr.s_addr = htonl(address.toIPv4Address());
        } else {
            sa = reinterpret_cast<sockaddr *>(&sa6);
            saSize = sizeof(sa6);
            memset(&sa6, 0, sizeof(sa6));
            sa6.sin6_family = AF_INET6;
            memcpy(&sa6.sin6_addr, address.toIPv6Address().c, sizeof(sa6.sin6_addr));
        }

        char hbuf[NI_MAXHOST];
        if (getnameinfo(sa, saSize, hbuf, sizeof(hbuf), 0, 0, 0) == 0)
            results.setHostName(QString::fromLatin1(hbuf));

        if (results.hostName().isEmpty())
            results.setHostName(address.toString());
        results.setAddresses(QList<QHostAddress>() << address);
        return results;
    }

    // IDN support
    QByteArray aceHostname = QUrl::toAce(hostName);
    results.setHostName(hostName);
    if (aceHostname.isEmpty()) {
        results.setError(QHostInfo::HostNotFound);
        results.setErrorString(hostName.isEmpty() ? tr("No host name given") : tr("Invalid hostname"));
        return results;
    }

    addrinfo *res;
    int err = getaddrinfo(aceHostname.constData(), 0, 0, &res);
    if (err == 0) {
        QList<QHostAddress> addresses;
        for (addrinfo *p = res; p != 0; p = p->ai_next) {
            switch (p->ai_family) {
            case AF_INET: {
                QHostAddress addr;
                addr.setAddress(ntohl(reinterpret_cast<sockaddr_in *>(p->ai_addr)->sin_addr.s_addr));
                if (!addresses.contains(addr))
                    addresses.append(addr);
            }
                break;
            case AF_INET6: {
                QHostAddress addr;
                addr.setAddress(reinterpret_cast<const sockaddr_in6 *>(p->ai_addr)->sin6_addr.s6_addr);
                if (!addresses.contains(addr))
                    addresses.append(addr);
            }
                break;
            default:
                results.setError(QHostInfo::UnknownError);
                results.setErrorString(tr("Unknown address type"));
            }
        }
        results.setAddresses(addresses);
        freeaddrinfo(res);
    } else {
        translateWSAError(WSAGetLastError(), &results);
    }

#if defined(QHOSTINFO_DEBUG)
    if (results.error() != QHostInfo::NoError) {
        qDebug("QHostInfoAgent::run(): error (%s)",
               results.errorString().toLatin1().constData());
    } else {
        QString tmp;
        QList<QHostAddress> addresses = results.addresses();
        for (int i = 0; i < addresses.count(); ++i) {
            if (i != 0) tmp += ", ";
            tmp += addresses.at(i).toString();
        }
        qDebug("QHostInfoAgent::run(): found %i entries: {%s}",
               addresses.count(), tmp.toLatin1().constData());
    }
#endif
    return results;
}

// QString QHostInfo::localDomainName() defined in qnetworkinterface_win.cpp

QT_END_NAMESPACE