/*
 * Bittorrent Client using Qt4 and libtorrent.
 * Copyright (C) 2006  Christophe Dumez
 *
 * This program 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 2
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * In addition, as a special exception, the copyright holders give permission to
 * link this program with the OpenSSL project's "OpenSSL" library (or with
 * modified versions of it that use the same license as the "OpenSSL" library),
 * and distribute the linked executables. You must obey the GNU General Public
 * License in all respects for all of the code used other than "OpenSSL".  If you
 * modify file(s), you may extend this exception to your version of the file(s),
 * but you are not obligated to do so. If you do not wish to do so, delete this
 * exception statement from your version.
 *
 * Contact : chris@qbittorrent.org
 */

#include <QTemporaryFile>
#include <QNetworkAccessManager>
#include <QNetworkRequest>
#include <QNetworkProxy>
#include <QNetworkCookieJar>
#include <QDebug>

#include "downloadthread.h"
#include "preferences.h"
#include "qinisettings.h"
#include "fs_utils.h"
#include <zlib.h>

/** Download Thread **/

DownloadThread::DownloadThread(QObject* parent) : QObject(parent) {
  connect(&m_networkManager, SIGNAL(finished (QNetworkReply*)), this, SLOT(processDlFinished(QNetworkReply*)));
#ifndef QT_NO_OPENSSL
  connect(&m_networkManager, SIGNAL(sslErrors(QNetworkReply*,QList<QSslError>)), this, SLOT(ignoreSslErrors(QNetworkReply*,QList<QSslError>)));
#endif
}

QByteArray DownloadThread::gUncompress(Bytef *inData, size_t len) {
  if (len <= 4) {
    qWarning("gUncompress: Input data is truncated");
    return QByteArray();
  }

  QByteArray result;

  z_stream strm;
  static const int CHUNK_SIZE = 1024;
  char out[CHUNK_SIZE];

  /* allocate inflate state */
  strm.zalloc = Z_NULL;
  strm.zfree = Z_NULL;
  strm.opaque = Z_NULL;
  strm.avail_in = len;
  strm.next_in = inData;

  const int windowBits = 15;
  const int ENABLE_ZLIB_GZIP = 32;

  int ret = inflateInit2(&strm, windowBits|ENABLE_ZLIB_GZIP ); // gzip decoding
  if (ret != Z_OK)
    return QByteArray();

  // run inflate()
  do {
    strm.avail_out = CHUNK_SIZE;
    strm.next_out = reinterpret_cast<unsigned char*>(out);

    ret = inflate(&strm, Z_NO_FLUSH);
    Q_ASSERT(ret != Z_STREAM_ERROR); // state not clobbered

    switch (ret) {
      case Z_NEED_DICT:
      case Z_DATA_ERROR:
      case Z_MEM_ERROR:
        (void) inflateEnd(&strm);
        return QByteArray();
    }

    result.append(out, CHUNK_SIZE - strm.avail_out);
  } while (!strm.avail_out);

  // clean up and return
  inflateEnd(&strm);
  return result;
}

void DownloadThread::processDlFinished(QNetworkReply* reply) {
  QString url = reply->url().toString();
  qDebug("Download finished: %s", qPrintable(url));
  // Check if the request was successful
  if (reply->error() != QNetworkReply::NoError) {
    // Failure
    qDebug("Download failure (%s), reason: %s", qPrintable(url), qPrintable(errorCodeToString(reply->error())));
    emit downloadFailure(url, errorCodeToString(reply->error()));
    reply->deleteLater();
    return;
  }
  // Check if the server ask us to redirect somewhere lese
  const QVariant redirection = reply->attribute(QNetworkRequest::RedirectionTargetAttribute);
  if (redirection.isValid()) {
    // We should redirect
    QUrl newUrl = redirection.toUrl();
    // Resolve relative urls
    if (newUrl.isRelative())
        newUrl = reply->url().resolved(newUrl);
    const QString newUrlString = newUrl.toString();
    qDebug("Redirecting from %s to %s", qPrintable(url), qPrintable(newUrlString));
    m_redirectMapping.insert(newUrlString, url);
    // redirecting with first cookies
    downloadUrl(newUrlString, m_networkManager.cookieJar()->cookiesForUrl(url));
    reply->deleteLater();
    return;
  }
  // Checking if it was redirected, restoring initial URL
  if (m_redirectMapping.contains(url)) {
    url = m_redirectMapping.take(url);
  }
  // Success
  QTemporaryFile *tmpfile = new QTemporaryFile;
  if (tmpfile->open()) {
    tmpfile->setAutoRemove(false);
    QString filePath = tmpfile->fileName();
    qDebug("Temporary filename is: %s", qPrintable(filePath));
    if (reply->isOpen() || reply->open(QIODevice::ReadOnly)) {
      QByteArray replyData = reply->readAll();
      if (reply->rawHeader("Content-Encoding") == "gzip") {
        // uncompress gzip reply
        replyData = gUncompress(reinterpret_cast<unsigned char*>(replyData.data()), replyData.length());
      }
      tmpfile->write(replyData);
      tmpfile->close();
      // XXX: tmpfile needs to be deleted on Windows before using the file
      // or it will complain that the file is used by another process.
      delete tmpfile;
      // Send finished signal
      emit downloadFinished(url, filePath);
    } else {
      delete tmpfile;
      fsutils::forceRemove(filePath);
      // Error when reading the request
      emit downloadFailure(url, tr("I/O Error"));
    }
  } else {
    delete tmpfile;
    emit downloadFailure(url, tr("I/O Error"));
  }
  // Clean up
  reply->deleteLater();
}

void DownloadThread::downloadTorrentUrl(const QString &url, const QList<QNetworkCookie>& cookies)
{
  // Process request
  QNetworkReply *reply = downloadUrl(url, cookies);
  connect(reply, SIGNAL(downloadProgress(qint64,qint64)), this, SLOT(checkDownloadSize(qint64,qint64)));
}

QNetworkReply* DownloadThread::downloadUrl(const QString &url, const QList<QNetworkCookie>& cookies) {
  // Update proxy settings
  applyProxySettings();
  // Set cookies
  if (!cookies.empty()) {
    qDebug("Setting %d cookies for url: %s", cookies.size(), qPrintable(url));
    m_networkManager.cookieJar()->setCookiesFromUrl(cookies, url);
  }
  // Process download request
  qDebug("url is %s", qPrintable(url));
  const QUrl qurl = QUrl::fromEncoded(url.toUtf8());
  QNetworkRequest request(qurl);
  // Spoof Firefox 3.5 user agent to avoid
  // Web server banning
  request.setRawHeader("User-Agent", "Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.9.1.5) Gecko/20091102 Firefox/3.5.5");
  qDebug("Downloading %s...", request.url().toEncoded().data());
  qDebug("%d cookies for this URL", m_networkManager.cookieJar()->cookiesForUrl(url).size());
  for (int i=0; i<m_networkManager.cookieJar()->cookiesForUrl(url).size(); ++i) {
    qDebug("%s=%s", m_networkManager.cookieJar()->cookiesForUrl(url).at(i).name().data(), m_networkManager.cookieJar()->cookiesForUrl(url).at(i).value().data());
    qDebug("Domain: %s, Path: %s", qPrintable(m_networkManager.cookieJar()->cookiesForUrl(url).at(i).domain()), qPrintable(m_networkManager.cookieJar()->cookiesForUrl(url).at(i).path()));
  }
  // accept gzip
  request.setRawHeader("Accept-Encoding", "gzip");
  return m_networkManager.get(request);
}

void DownloadThread::checkDownloadSize(qint64 bytesReceived, qint64 bytesTotal) {
  QNetworkReply *reply = qobject_cast<QNetworkReply*>(sender());
  if (!reply) return;
  if (bytesTotal > 0) {
    // Total number of bytes is available
    if (bytesTotal > 1048576*10) {
      // More than 10MB, this is probably not a torrent file, aborting...
      reply->abort();
      reply->deleteLater();
    } else {
      disconnect(reply, SIGNAL(downloadProgress(qint64,qint64)), this, SLOT(checkDownloadSize(qint64,qint64)));
    }
  } else {
    if (bytesReceived  > 1048576*10) {
      // More than 10MB, this is probably not a torrent file, aborting...
      reply->abort();
      reply->deleteLater();
    }
  }
}

void DownloadThread::applyProxySettings() {
  QNetworkProxy proxy;
  const Preferences* const pref = Preferences::instance();
  if (pref->isProxyEnabled()) {
    // Proxy enabled
    proxy.setHostName(pref->getProxyIp());
    proxy.setPort(pref->getProxyPort());
    // Default proxy type is HTTP, we must change if it is SOCKS5
    const int proxy_type = pref->getProxyType();
    if (proxy_type == Proxy::SOCKS5 || proxy_type == Proxy::SOCKS5_PW) {
      qDebug() << Q_FUNC_INFO << "using SOCKS proxy";
      proxy.setType(QNetworkProxy::Socks5Proxy);
    } else {
      qDebug() << Q_FUNC_INFO << "using HTTP proxy";
      proxy.setType(QNetworkProxy::HttpProxy);
    }
    // Authentication?
    if (pref->isProxyAuthEnabled()) {
      qDebug("Proxy requires authentication, authenticating");
      proxy.setUser(pref->getProxyUsername());
      proxy.setPassword(pref->getProxyPassword());
    }
  } else {
    proxy.setType(QNetworkProxy::NoProxy);
  }
  m_networkManager.setProxy(proxy);
}

QString DownloadThread::errorCodeToString(QNetworkReply::NetworkError status) {
  switch(status) {
  case QNetworkReply::HostNotFoundError:
    return tr("The remote host name was not found (invalid hostname)");
  case QNetworkReply::OperationCanceledError:
    return tr("The operation was canceled");
  case QNetworkReply::RemoteHostClosedError:
    return tr("The remote server closed the connection prematurely, before the entire reply was received and processed");
  case QNetworkReply::TimeoutError:
    return tr("The connection to the remote server timed out");
  case QNetworkReply::SslHandshakeFailedError:
    return tr("SSL/TLS handshake failed");
  case QNetworkReply::ConnectionRefusedError:
    return tr("The remote server refused the connection");
  case QNetworkReply::ProxyConnectionRefusedError:
    return tr("The connection to the proxy server was refused");
  case QNetworkReply::ProxyConnectionClosedError:
    return tr("The proxy server closed the connection prematurely");
  case QNetworkReply::ProxyNotFoundError:
    return tr("The proxy host name was not found");
  case QNetworkReply::ProxyTimeoutError:
    return tr("The connection to the proxy timed out or the proxy did not reply in time to the request sent");
  case QNetworkReply::ProxyAuthenticationRequiredError:
    return tr("The proxy requires authentication in order to honour the request but did not accept any credentials offered");
  case QNetworkReply::ContentAccessDenied:
    return tr("The access to the remote content was denied (401)");
  case QNetworkReply::ContentOperationNotPermittedError:
    return tr("The operation requested on the remote content is not permitted");
  case QNetworkReply::ContentNotFoundError:
    return tr("The remote content was not found at the server (404)");
  case QNetworkReply::AuthenticationRequiredError:
    return tr("The remote server requires authentication to serve the content but the credentials provided were not accepted");
  case QNetworkReply::ProtocolUnknownError:
    return tr("The Network Access API cannot honor the request because the protocol is not known");
  case QNetworkReply::ProtocolInvalidOperationError:
    return tr("The requested operation is invalid for this protocol");
  case QNetworkReply::UnknownNetworkError:
    return tr("An unknown network-related error was detected");
  case QNetworkReply::UnknownProxyError:
    return tr("An unknown proxy-related error was detected");
  case QNetworkReply::UnknownContentError:
    return tr("An unknown error related to the remote content was detected");
  case QNetworkReply::ProtocolFailure:
    return tr("A breakdown in protocol was detected");
  default:
    return tr("Unknown error");
  }
}

#ifndef QT_NO_OPENSSL
void DownloadThread::ignoreSslErrors(QNetworkReply* reply, const QList<QSslError> &errors) {
  Q_UNUSED(errors)
  // Ignore all SSL errors
  reply->ignoreSslErrors();
}
#endif
