/****************************************************************************
**
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtNetwork module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
** 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
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** use the contact form at http://qt.digia.com/contact-us.
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** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 or version 3 as published by the Free
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** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
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**
** In addition, as a special exception, Digia gives you certain additional
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** $QT_END_LICENSE$
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****************************************************************************/

#include "qnetworkproxy.h"

#ifndef QT_NO_NETWORKPROXY

#include <qmutex.h>
#include <qstringlist.h>
#include <qregexp.h>
#include <qurl.h>
#include <private/qsystemlibrary_p.h>
#include <qnetworkinterface.h>

#include <string.h>
#include <qt_windows.h>
#include <wininet.h>
#include <lmcons.h>
#include "qnetworkfunctions_wince.h"

/*
 * Information on the WinHTTP DLL:
 *  http://msdn.microsoft.com/en-us/library/aa384122(VS.85).aspx example for WPAD
 *
 *  http://msdn.microsoft.com/en-us/library/aa384097(VS.85).aspx WinHttpGetProxyForUrl
 *  http://msdn.microsoft.com/en-us/library/aa384096(VS.85).aspx WinHttpGetIEProxyConfigForCurrentUs
 *  http://msdn.microsoft.com/en-us/library/aa384095(VS.85).aspx WinHttpGetDefaultProxyConfiguration
 */

// We don't want to include winhttp.h because that's not
// present in some Windows SDKs (I don't know why)
// So, instead, copy the definitions here

typedef struct {
  DWORD dwFlags;
  DWORD dwAutoDetectFlags;
  LPCWSTR lpszAutoConfigUrl;
  LPVOID lpvReserved;
  DWORD dwReserved;
  BOOL fAutoLogonIfChallenged;
} WINHTTP_AUTOPROXY_OPTIONS;

typedef struct {
  DWORD dwAccessType;
  LPWSTR lpszProxy;
  LPWSTR lpszProxyBypass;
} WINHTTP_PROXY_INFO;

typedef struct {
  BOOL fAutoDetect;
  LPWSTR lpszAutoConfigUrl;
  LPWSTR lpszProxy;
  LPWSTR lpszProxyBypass;
} WINHTTP_CURRENT_USER_IE_PROXY_CONFIG;

#define WINHTTP_AUTOPROXY_AUTO_DETECT           0x00000001
#define WINHTTP_AUTOPROXY_CONFIG_URL            0x00000002

#define WINHTTP_AUTO_DETECT_TYPE_DHCP           0x00000001
#define WINHTTP_AUTO_DETECT_TYPE_DNS_A          0x00000002

#define WINHTTP_ACCESS_TYPE_DEFAULT_PROXY               0
#define WINHTTP_ACCESS_TYPE_NO_PROXY                    1
#define WINHTTP_ACCESS_TYPE_NAMED_PROXY                 3

#define WINHTTP_NO_PROXY_NAME     NULL
#define WINHTTP_NO_PROXY_BYPASS   NULL

#define WINHTTP_ERROR_BASE                      12000
#define ERROR_WINHTTP_LOGIN_FAILURE             (WINHTTP_ERROR_BASE + 15)
#define ERROR_WINHTTP_UNABLE_TO_DOWNLOAD_SCRIPT (WINHTTP_ERROR_BASE + 167)
#define ERROR_WINHTTP_AUTODETECTION_FAILED      (WINHTTP_ERROR_BASE + 180)

QT_BEGIN_NAMESPACE

typedef BOOL (WINAPI * PtrWinHttpGetProxyForUrl)(HINTERNET, LPCWSTR, WINHTTP_AUTOPROXY_OPTIONS*, WINHTTP_PROXY_INFO*);
typedef HINTERNET (WINAPI * PtrWinHttpOpen)(LPCWSTR, DWORD, LPCWSTR, LPCWSTR,DWORD);
typedef BOOL (WINAPI * PtrWinHttpGetDefaultProxyConfiguration)(WINHTTP_PROXY_INFO*);
typedef BOOL (WINAPI * PtrWinHttpGetIEProxyConfigForCurrentUser)(WINHTTP_CURRENT_USER_IE_PROXY_CONFIG*);
typedef BOOL (WINAPI * PtrWinHttpCloseHandle)(HINTERNET);
typedef BOOL (WINAPI * PtrCloseServiceHandle)(SC_HANDLE hSCObject);
static PtrWinHttpGetProxyForUrl ptrWinHttpGetProxyForUrl = 0;
static PtrWinHttpOpen ptrWinHttpOpen = 0;
static PtrWinHttpGetDefaultProxyConfiguration ptrWinHttpGetDefaultProxyConfiguration = 0;
static PtrWinHttpGetIEProxyConfigForCurrentUser ptrWinHttpGetIEProxyConfigForCurrentUser = 0;
static PtrWinHttpCloseHandle ptrWinHttpCloseHandle = 0;


#ifndef Q_OS_WINCE
static bool currentProcessIsService()
{
    typedef BOOL (WINAPI *PtrGetUserName)(LPTSTR lpBuffer, LPDWORD lpnSize);
    typedef BOOL (WINAPI *PtrLookupAccountName)(LPCTSTR lpSystemName, LPCTSTR lpAccountName, PSID Sid,
                                  LPDWORD cbSid, LPTSTR ReferencedDomainName, LPDWORD cchReferencedDomainName, PSID_NAME_USE peUse);
    static PtrGetUserName ptrGetUserName = (PtrGetUserName)QSystemLibrary::resolve(QLatin1String("Advapi32"), "GetUserNameW");
    static PtrLookupAccountName ptrLookupAccountName = (PtrLookupAccountName)QSystemLibrary::resolve(QLatin1String("Advapi32"), "LookupAccountNameW");

    if (ptrGetUserName && ptrLookupAccountName) {
        wchar_t userName[UNLEN + 1] = L"";
        DWORD size = UNLEN;
        if (ptrGetUserName(userName, &size)) {
            SID_NAME_USE type = SidTypeUser;
            DWORD dummy = MAX_PATH;
            wchar_t dummyStr[MAX_PATH] = L"";
            PSID psid = 0;
            if (ptrLookupAccountName(NULL, userName, &psid, &dummy, dummyStr, &dummy, &type))
                return type != SidTypeUser; //returns true if the current user is not a user
        }
    }
    return false;
}
#endif // ! Q_OS_WINCE

static QStringList splitSpaceSemicolon(const QString &source)
{
    QStringList list;
    int start = 0;
    int end;
    while (true) {
        int space = source.indexOf(QLatin1Char(' '), start);
        int semicolon = source.indexOf(QLatin1Char(';'), start);
        end = space;
        if (semicolon != -1 && (end == -1 || semicolon < end))
            end = semicolon;

        if (end == -1) {
            if (start != source.length())
                list.append(source.mid(start));
            return list;
        }
        if (start != end)
            list.append(source.mid(start, end - start));
        start = end + 1;
    }
    return list;
}

static bool isBypassed(const QString &host, const QStringList &bypassList)
{
    if (host.isEmpty())
        return false;

    bool isSimple = !host.contains(QLatin1Char('.')) && !host.contains(QLatin1Char(':'));

    QHostAddress ipAddress;
    bool isIpAddress = ipAddress.setAddress(host);

    // always exclude loopback
    if (isIpAddress && ipAddress.isLoopback())
        return true;

    // does it match the list of exclusions?
    foreach (const QString &entry, bypassList) {
        if (entry == QLatin1String("<local>")) {
            if (isSimple)
                return true;
            if (isIpAddress) {
                //exclude all local subnets
                foreach (const QNetworkInterface &iface, QNetworkInterface::allInterfaces()) {
                    foreach (const QNetworkAddressEntry netaddr, iface.addressEntries()) {
                        if (ipAddress.isInSubnet(netaddr.ip(), netaddr.prefixLength())) {
                            return true;
                        }
                    }
                }
            }
        }
        if (isIpAddress && ipAddress.isInSubnet(QHostAddress::parseSubnet(entry))) {
            return true;        // excluded
        } else {
            // do wildcard matching
            QRegExp rx(entry, Qt::CaseInsensitive, QRegExp::Wildcard);
            if (rx.exactMatch(host))
                return true;
        }
    }

    // host was not excluded
    return false;
}

static QList<QNetworkProxy> filterProxyListByCapabilities(const QList<QNetworkProxy> &proxyList, const QNetworkProxyQuery &query)
{
    QNetworkProxy::Capabilities requiredCaps;
    switch (query.queryType()) {
    case QNetworkProxyQuery::TcpSocket:
        requiredCaps = QNetworkProxy::TunnelingCapability;
        break;
    case QNetworkProxyQuery::UdpSocket:
        requiredCaps = QNetworkProxy::UdpTunnelingCapability;
        break;
    case QNetworkProxyQuery::TcpServer:
        requiredCaps = QNetworkProxy::ListeningCapability;
        break;
    default:
        return proxyList;
        break;
    }
    QList<QNetworkProxy> result;
    foreach (const QNetworkProxy& proxy, proxyList) {
        if (proxy.capabilities() & requiredCaps)
            result.append(proxy);
    }
    return result;
}

static QList<QNetworkProxy> removeDuplicateProxies(const QList<QNetworkProxy> &proxyList)
{
    QList<QNetworkProxy> result;
     foreach (QNetworkProxy proxy, proxyList) {
         bool append = true;
         for (int i=0; i < result.count(); i++) {
             if (proxy.hostName() == result.at(i).hostName()
                 && proxy.port() == result.at(i).port()) {
                     append = false;
                     // HttpProxy trumps FtpCachingProxy or HttpCachingProxy on the same host/port
                     if (proxy.type() == QNetworkProxy::HttpProxy)
                         result[i] = proxy;
             }
         }
         if (append)
             result.append(proxy);
     }
     return result;
}

static QList<QNetworkProxy> parseServerList(const QNetworkProxyQuery &query, const QStringList &proxyList)
{
    // Reference documentation from Microsoft:
    // http://msdn.microsoft.com/en-us/library/aa383912(VS.85).aspx
    //
    // According to the website, the proxy server list is
    // one or more of the space- or semicolon-separated strings in the format:
    //   ([<scheme>=][<scheme>"://"]<server>[":"<port>])
    // The first scheme relates to the protocol tag
    // The second scheme, if present, overrides the proxy type

    QList<QNetworkProxy> result;
    QHash<QString, QNetworkProxy> taggedProxies;
    const QString requiredTag = query.protocolTag();
    bool checkTags = !requiredTag.isEmpty() && query.queryType() != QNetworkProxyQuery::TcpServer; //windows tags are only for clients
    foreach (const QString &entry, proxyList) {
        int server = 0;

        QNetworkProxy::ProxyType proxyType = QNetworkProxy::HttpProxy;
        quint16 port = 8080;

        int pos = entry.indexOf(QLatin1Char('='));
        QStringRef scheme;
        QStringRef protocolTag;
        if (pos != -1) {
            scheme = protocolTag = entry.leftRef(pos);
            server = pos + 1;
        }
        pos = entry.indexOf(QLatin1String("://"), server);
        if (pos != -1) {
            scheme = entry.midRef(server, pos - server);
            server = pos + 3;
        }

        if (!scheme.isEmpty()) {
            if (scheme == QLatin1String("http") || scheme == QLatin1String("https")) {
                // no-op
                // defaults are above
            } else if (scheme == QLatin1String("socks") || scheme == QLatin1String("socks5")) {
                proxyType = QNetworkProxy::Socks5Proxy;
                port = 1080;
            } else if (scheme == QLatin1String("ftp")) {
                proxyType = QNetworkProxy::FtpCachingProxy;
                port = 2121;
            } else {
                // unknown proxy type
                continue;
            }
        }

        pos = entry.indexOf(QLatin1Char(':'), server);
        if (pos != -1) {
            bool ok;
            uint value = entry.mid(pos + 1).toUInt(&ok);
            if (!ok || value > 65535)
                continue;       // invalid port number

            port = value;
        } else {
            pos = entry.length();
        }

        result << QNetworkProxy(proxyType, entry.mid(server, pos - server), port);
        if (!protocolTag.isEmpty())
            taggedProxies.insert(protocolTag.toString(), result.last());
    }

    if (checkTags && taggedProxies.contains(requiredTag)) {
        if (query.queryType() == QNetworkProxyQuery::UrlRequest) {
            result.clear();
            result.append(taggedProxies.value(requiredTag));
            return result;
        } else {
            result.prepend(taggedProxies.value(requiredTag));
        }
    }
    if (!checkTags || requiredTag != QLatin1String("http")) {
        // if there are different http proxies for http and https, prefer the https one (more likely to be capable of CONNECT)
        QNetworkProxy httpProxy = taggedProxies.value(QLatin1String("http"));
        QNetworkProxy httpsProxy = taggedProxies.value(QLatin1String("http"));
        if (httpProxy != httpsProxy && httpProxy.type() == QNetworkProxy::HttpProxy && httpsProxy.type() == QNetworkProxy::HttpProxy) {
            for (int i = 0; i < result.count(); i++) {
                if (httpProxy == result.at(i))
                    result[i].setType(QNetworkProxy::HttpCachingProxy);
            }
        }
    }
    result = filterProxyListByCapabilities(result, query);
    return removeDuplicateProxies(result);
}

class QWindowsSystemProxy
{
public:
    QWindowsSystemProxy();
    ~QWindowsSystemProxy();
    void init();

    QMutex mutex;

    HINTERNET hHttpSession;
    WINHTTP_AUTOPROXY_OPTIONS autoProxyOptions;

    QString autoConfigUrl;
    QStringList proxyServerList;
    QStringList proxyBypass;
    QList<QNetworkProxy> defaultResult;

    bool initialized;
    bool functional;
    bool isAutoConfig;
};

Q_GLOBAL_STATIC(QWindowsSystemProxy, systemProxy)

QWindowsSystemProxy::QWindowsSystemProxy()
    : hHttpSession(0), initialized(false), functional(false), isAutoConfig(false)
{
    defaultResult << QNetworkProxy::NoProxy;
}

QWindowsSystemProxy::~QWindowsSystemProxy()
{
    if (hHttpSession)
        ptrWinHttpCloseHandle(hHttpSession);
}

void QWindowsSystemProxy::init()
{
    if (initialized)
        return;
    initialized = true;

#ifdef Q_OS_WINCE
    // Windows CE does not have any of the following API
    return;
#else
    // load the winhttp.dll library
    QSystemLibrary lib(L"winhttp");
    if (!lib.load())
        return;                 // failed to load

    ptrWinHttpOpen = (PtrWinHttpOpen)lib.resolve("WinHttpOpen");
    ptrWinHttpCloseHandle = (PtrWinHttpCloseHandle)lib.resolve("WinHttpCloseHandle");
    ptrWinHttpGetProxyForUrl = (PtrWinHttpGetProxyForUrl)lib.resolve("WinHttpGetProxyForUrl");
    ptrWinHttpGetDefaultProxyConfiguration = (PtrWinHttpGetDefaultProxyConfiguration)lib.resolve("WinHttpGetDefaultProxyConfiguration");
    ptrWinHttpGetIEProxyConfigForCurrentUser = (PtrWinHttpGetIEProxyConfigForCurrentUser)lib.resolve("WinHttpGetIEProxyConfigForCurrentUser");

    // Try to obtain the Internet Explorer configuration.
    WINHTTP_CURRENT_USER_IE_PROXY_CONFIG ieProxyConfig;
    const bool hasIEConfig = ptrWinHttpGetIEProxyConfigForCurrentUser(&ieProxyConfig);
    if (hasIEConfig) {
        if (ieProxyConfig.lpszAutoConfigUrl) {
            autoConfigUrl = QString::fromWCharArray(ieProxyConfig.lpszAutoConfigUrl);
            GlobalFree(ieProxyConfig.lpszAutoConfigUrl);
        }
        if (ieProxyConfig.lpszProxy) {
            // http://msdn.microsoft.com/en-us/library/aa384250%28VS.85%29.aspx speaks only about a "proxy URL",
            // not multiple URLs. However we tested this and it can return multiple URLs. So we use splitSpaceSemicolon
            // on it.
            proxyServerList = splitSpaceSemicolon(QString::fromWCharArray(ieProxyConfig.lpszProxy));
            GlobalFree(ieProxyConfig.lpszProxy);
        }
        if (ieProxyConfig.lpszProxyBypass) {
            proxyBypass = splitSpaceSemicolon(QString::fromWCharArray(ieProxyConfig.lpszProxyBypass));
            GlobalFree(ieProxyConfig.lpszProxyBypass);
        }
    }

    if (!hasIEConfig ||
        (currentProcessIsService() && proxyServerList.isEmpty() && proxyBypass.isEmpty())) {
        // no user configuration
        // attempt to get the default configuration instead
        // that config will serve as default if WPAD fails
        WINHTTP_PROXY_INFO proxyInfo;
        if (ptrWinHttpGetDefaultProxyConfiguration(&proxyInfo) &&
            proxyInfo.dwAccessType == WINHTTP_ACCESS_TYPE_NAMED_PROXY) {
            // we got information from the registry
            // overwrite the IE configuration, if any

            proxyBypass = splitSpaceSemicolon(QString::fromWCharArray(proxyInfo.lpszProxyBypass));
            proxyServerList = splitSpaceSemicolon(QString::fromWCharArray(proxyInfo.lpszProxy));
        }

        if (proxyInfo.lpszProxy)
            GlobalFree(proxyInfo.lpszProxy);
        if (proxyInfo.lpszProxyBypass)
            GlobalFree(proxyInfo.lpszProxyBypass);
    }

    hHttpSession = NULL;
    if (ieProxyConfig.fAutoDetect || !autoConfigUrl.isEmpty()) {
        // open the handle and obtain the options
        hHttpSession = ptrWinHttpOpen(L"Qt System Proxy access/1.0",
                                      WINHTTP_ACCESS_TYPE_NO_PROXY,
                                      WINHTTP_NO_PROXY_NAME,
                                      WINHTTP_NO_PROXY_BYPASS,
                                      0);
        if (!hHttpSession)
            return;

        isAutoConfig = true;
        memset(&autoProxyOptions, 0, sizeof autoProxyOptions);
        autoProxyOptions.fAutoLogonIfChallenged = false;
        //Although it is possible to specify dwFlags = WINHTTP_AUTOPROXY_AUTO_DETECT | WINHTTP_AUTOPROXY_CONFIG_URL
        //this has poor performance (WPAD is attempted for every url, taking 2.5 seconds per interface,
        //before the configured pac file is used)
        if (ieProxyConfig.fAutoDetect) {
            autoProxyOptions.dwFlags = WINHTTP_AUTOPROXY_AUTO_DETECT;
            autoProxyOptions.dwAutoDetectFlags = WINHTTP_AUTO_DETECT_TYPE_DHCP |
                                                 WINHTTP_AUTO_DETECT_TYPE_DNS_A;
        } else {
            autoProxyOptions.dwFlags = WINHTTP_AUTOPROXY_CONFIG_URL;
            autoProxyOptions.lpszAutoConfigUrl = (LPCWSTR)autoConfigUrl.utf16();
        }
    }

    functional = isAutoConfig || !proxyServerList.isEmpty();
#endif
}

QList<QNetworkProxy> QNetworkProxyFactory::systemProxyForQuery(const QNetworkProxyQuery &query)
{
    QWindowsSystemProxy *sp = systemProxy();
    if (!sp)
        return QList<QNetworkProxy>() << QNetworkProxy();

    QMutexLocker locker(&sp->mutex);
    sp->init();
    if (!sp->functional)
        return sp->defaultResult;

    if (sp->isAutoConfig) {
        WINHTTP_PROXY_INFO proxyInfo;

        // try to get the proxy config for the URL
        QUrl url = query.url();
        // url could be empty, e.g. from QNetworkProxy::applicationProxy(), that's fine,
        // we'll still ask for the proxy.
        // But for a file url, we know we don't need one.
        if (url.scheme() == QLatin1String("file") || url.scheme() == QLatin1String("qrc"))
            return sp->defaultResult;
        if (query.queryType() != QNetworkProxyQuery::UrlRequest) {
            // change the scheme to https, maybe it'll work
            url.setScheme(QLatin1String("https"));
        }

        bool getProxySucceeded = ptrWinHttpGetProxyForUrl(sp->hHttpSession,
                                                (LPCWSTR)url.toString().utf16(),
                                                &sp->autoProxyOptions,
                                                &proxyInfo);
        DWORD getProxyError = GetLastError();

        if (!getProxySucceeded
            && (ERROR_WINHTTP_AUTODETECTION_FAILED == getProxyError)) {
            // WPAD failed
            if (sp->autoConfigUrl.isEmpty()) {
                //No config file could be retrieved on the network.
                //Don't search for it next time again.
                sp->isAutoConfig = false;
            } else {
                //pac file URL is specified as well, try using that
                sp->autoProxyOptions.dwFlags = WINHTTP_AUTOPROXY_CONFIG_URL;
                sp->autoProxyOptions.lpszAutoConfigUrl = (LPCWSTR)sp->autoConfigUrl.utf16();
                getProxySucceeded = ptrWinHttpGetProxyForUrl(sp->hHttpSession,
                                                (LPCWSTR)url.toString().utf16(),
                                                &sp->autoProxyOptions,
                                                &proxyInfo);
                getProxyError = GetLastError();
            }
        }

        if (!getProxySucceeded
            && (ERROR_WINHTTP_LOGIN_FAILURE == getProxyError)) {
            // We first tried without AutoLogon, because this might prevent caching the result.
            // But now we've to enable it (http://msdn.microsoft.com/en-us/library/aa383153%28v=VS.85%29.aspx)
            sp->autoProxyOptions.fAutoLogonIfChallenged = TRUE;
            getProxySucceeded = ptrWinHttpGetProxyForUrl(sp->hHttpSession,
                                               (LPCWSTR)url.toString().utf16(),
                                                &sp->autoProxyOptions,
                                                &proxyInfo);
            getProxyError = GetLastError();
        }

        if (!getProxySucceeded
            && (ERROR_WINHTTP_UNABLE_TO_DOWNLOAD_SCRIPT == getProxyError)) {
            // PAC file url is not connectable, or server returned error (e.g. http 404)
            //Don't search for it next time again.
            sp->isAutoConfig = false;
        }

        if (getProxySucceeded) {
            // yes, we got a config for this URL
            QString proxyBypass = QString::fromWCharArray(proxyInfo.lpszProxyBypass);
            QStringList proxyServerList = splitSpaceSemicolon(QString::fromWCharArray(proxyInfo.lpszProxy));
            if (proxyInfo.lpszProxy)
                GlobalFree(proxyInfo.lpszProxy);
            if (proxyInfo.lpszProxyBypass)
                GlobalFree(proxyInfo.lpszProxyBypass);

            if (proxyInfo.dwAccessType == WINHTTP_ACCESS_TYPE_NO_PROXY)
                return sp->defaultResult; //i.e. the PAC file result was "DIRECT"
            if (isBypassed(query.peerHostName(), splitSpaceSemicolon(proxyBypass)))
                return sp->defaultResult;
            return parseServerList(query, proxyServerList);
        }

        // GetProxyForUrl failed, fall back to static configuration
    }

    // static configuration
    if (isBypassed(query.peerHostName(), sp->proxyBypass))
        return sp->defaultResult;

    QList<QNetworkProxy> result = parseServerList(query, sp->proxyServerList);
    // In some cases, this was empty. See SF task 00062670
    if (result.isEmpty())
        return sp->defaultResult;

    return result;
}

QT_END_NAMESPACE

#endif
