/* <!-- copyright */
/*
 * aria2 - The high speed download utility
 *
 * Copyright (C) 2006 Tatsuhiro Tsujikawa
 *
 * 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 the code of portions of this program with the
 * OpenSSL library under certain conditions as described in each
 * individual source file, and distribute linked combinations
 * including the two.
 * 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) with this exception, 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.  If you delete this exception statement from all source
 * files in the program, then also delete it here.
 */
/* copyright --> */
#include "HttpResponse.h"
#include "Request.h"
#include "Segment.h"
#include "HttpRequest.h"
#include "HttpHeader.h"
#include "Range.h"
#include "LogFactory.h"
#include "Logger.h"
#include "util.h"
#include "message.h"
#include "DlAbortEx.h"
#include "DlRetryEx.h"
#include "fmt.h"
#include "A2STR.h"
#include "CookieStorage.h"
#include "AuthConfigFactory.h"
#include "AuthConfig.h"
#include "ChunkedDecodingStreamFilter.h"
#include "error_code.h"
#include "prefs.h"
#include "Option.h"
#include "Checksum.h"
#include "uri.h"
#include "MetalinkHttpEntry.h"
#include "Base64.h"
#ifdef ENABLE_MESSAGE_DIGEST
#include "MessageDigest.h"
#endif // ENABLE_MESSAGE_DIGEST
#ifdef HAVE_ZLIB
# include "GZipDecodingStreamFilter.h"
#endif // HAVE_ZLIB

namespace aria2 {

HttpResponse::HttpResponse()
  : cuid_(0)
{}

HttpResponse::~HttpResponse() {}

void HttpResponse::validateResponse() const
{
  int statusCode = getStatusCode();
  if(statusCode >= 400) {
    return;
  }
  if(statusCode == 304) {
    if(!httpRequest_->conditionalRequest()) {
      throw DL_ABORT_EX2("Got 304 without If-Modified-Since or If-None-Match",
                         error_code::HTTP_PROTOCOL_ERROR);
    }
  } else if(statusCode == 301 ||
            statusCode == 302 ||
            statusCode == 303 ||
            statusCode == 307) {
    if(!httpHeader_->defined(HttpHeader::LOCATION)) {
      throw DL_ABORT_EX2(fmt(EX_LOCATION_HEADER_REQUIRED, statusCode),
                         error_code::HTTP_PROTOCOL_ERROR);
    }
    return;
  } else if(statusCode == 200 || statusCode == 206) {
    if(!httpHeader_->defined(HttpHeader::TRANSFER_ENCODING)) {
      // compare the received range against the requested range
      RangeHandle responseRange = httpHeader_->getRange();
      if(!httpRequest_->isRangeSatisfied(responseRange)) {
        throw DL_ABORT_EX2
          (fmt(EX_INVALID_RANGE_HEADER,
               util::itos(httpRequest_->getStartByte(), true).c_str(),
               util::itos(httpRequest_->getEndByte(), true).c_str(),
               util::uitos(httpRequest_->getEntityLength(), true).c_str(),
               util::itos(responseRange->getStartByte(), true).c_str(),
               util::itos(responseRange->getEndByte(), true).c_str(),
               util::uitos(responseRange->getEntityLength(), true).c_str()),
           error_code::CANNOT_RESUME);
      }
    }
  } else {
    throw DL_ABORT_EX2(fmt("Unexpected status %d", statusCode),
                       error_code::HTTP_PROTOCOL_ERROR);
  }
}

std::string HttpResponse::determinFilename() const
{
  std::string contentDisposition =
    util::getContentDispositionFilename
    (httpHeader_->getFirst(HttpHeader::CONTENT_DISPOSITION));
  if(contentDisposition.empty()) {
    std::string file =
      util::percentDecode(httpRequest_->getFile().begin(),
                          httpRequest_->getFile().end());
    if(file.empty()) {
      return "index.html";
    } else {
      return file;
    }
  } else {
    A2_LOG_INFO(fmt(MSG_CONTENT_DISPOSITION_DETECTED,
                    cuid_,
                    contentDisposition.c_str()));
    return contentDisposition;
  }
}

void HttpResponse::retrieveCookie()
{
  Time now;
  std::pair<std::multimap<std::string, std::string>::const_iterator,
            std::multimap<std::string, std::string>::const_iterator> r =
    httpHeader_->getIterator(HttpHeader::SET_COOKIE);
  for(; r.first != r.second; ++r.first) {
    httpRequest_->getCookieStorage()->parseAndStore
      ((*r.first).second, httpRequest_->getHost(), httpRequest_->getDir(),
       now.getTime());
  }
}

bool HttpResponse::isRedirect() const
{
  int statusCode = getStatusCode();
  return (301 == statusCode ||
          302 == statusCode ||
          303 == statusCode ||
          307 == statusCode) &&
    httpHeader_->defined(HttpHeader::LOCATION);
}

void HttpResponse::processRedirect()
{
  
  if(httpRequest_->getRequest()->redirectUri
     (util::percentEncodeMini(getRedirectURI()))) {
    A2_LOG_INFO(fmt(MSG_REDIRECT,
                    cuid_,
                    httpRequest_->getRequest()->getCurrentUri().c_str()));
  } else {
    throw DL_RETRY_EX
      (fmt("CUID#%lld - Redirect to %s failed. It may not be a valid URI.",
           cuid_,
           httpRequest_->getRequest()->getCurrentUri().c_str()));
  }
}

const std::string& HttpResponse::getRedirectURI() const
{
  return httpHeader_->getFirst(HttpHeader::LOCATION);
}

bool HttpResponse::isTransferEncodingSpecified() const
{
  return httpHeader_->defined(HttpHeader::TRANSFER_ENCODING);
}

const std::string& HttpResponse::getTransferEncoding() const
{
  // TODO See TODO in getTransferEncodingStreamFilter()
  return httpHeader_->getFirst(HttpHeader::TRANSFER_ENCODING);
}

SharedHandle<StreamFilter> HttpResponse::getTransferEncodingStreamFilter() const
{
  SharedHandle<StreamFilter> filter;
  // TODO Transfer-Encoding header field can contains multiple tokens. We should
  // parse the field and retrieve each token.
  if(isTransferEncodingSpecified()) {
    if(getTransferEncoding() == HttpHeader::CHUNKED) {
      filter.reset(new ChunkedDecodingStreamFilter());
    }
  }
  return filter;
}

bool HttpResponse::isContentEncodingSpecified() const
{
  return httpHeader_->defined(HttpHeader::CONTENT_ENCODING);
}

const std::string& HttpResponse::getContentEncoding() const
{
  return httpHeader_->getFirst(HttpHeader::CONTENT_ENCODING);
}

SharedHandle<StreamFilter> HttpResponse::getContentEncodingStreamFilter() const
{
  SharedHandle<StreamFilter> filter;
#ifdef HAVE_ZLIB
  if(getContentEncoding() == HttpHeader::GZIP ||
     getContentEncoding() == HttpHeader::DEFLATE) {
    filter.reset(new GZipDecodingStreamFilter());
  }
#endif // HAVE_ZLIB
  return filter;
}

uint64_t HttpResponse::getContentLength() const
{
  if(!httpHeader_) {
    return 0;
  } else {
    return httpHeader_->getRange()->getContentLength();
  }
}

uint64_t HttpResponse::getEntityLength() const
{
  if(!httpHeader_) {
    return 0;
  } else {
    return httpHeader_->getRange()->getEntityLength();
  }
}

std::string HttpResponse::getContentType() const
{
  if(!httpHeader_) {
    return A2STR::NIL;
  } else {
    std::pair<std::string, std::string> p;
    util::divide(p, httpHeader_->getFirst(HttpHeader::CONTENT_TYPE), ';');
    return p.first;
  }
}

void HttpResponse::setHttpHeader(const SharedHandle<HttpHeader>& httpHeader)
{
  httpHeader_ = httpHeader;
}

void HttpResponse::setHttpRequest(const SharedHandle<HttpRequest>& httpRequest)
{
  httpRequest_ = httpRequest;
}

int HttpResponse::getStatusCode() const
{
  return httpHeader_->getStatusCode();
}

bool HttpResponse::hasRetryAfter() const
{
  return httpHeader_->defined(HttpHeader::RETRY_AFTER);
}

time_t HttpResponse::getRetryAfter() const
{
  return httpHeader_->getFirstAsUInt(HttpHeader::RETRY_AFTER);
}

Time HttpResponse::getLastModifiedTime() const
{
  return Time::parseHTTPDate(httpHeader_->getFirst(HttpHeader::LAST_MODIFIED));
}

bool HttpResponse::supportsPersistentConnection() const
{
  std::string connection =
    util::toLower(httpHeader_->getFirst(HttpHeader::CONNECTION));
  std::string version = httpHeader_->getVersion();

  return
    connection.find(HttpHeader::CLOSE) == std::string::npos &&
    (version == HttpHeader::HTTP_1_1 ||
     connection.find("keep-alive") != std::string::npos) &&
    (!httpRequest_->isProxyRequestSet() ||
     util::toLower(httpHeader_->getFirst("Proxy-Connection")).find("keep-alive")
     != std::string::npos);
}

namespace {
bool parseMetalinkHttpLink(MetalinkHttpEntry& result, const std::string& s)
{
  std::string::const_iterator first = std::find(s.begin(), s.end(), '<');
  if(first == s.end()) {
    return false;
  }
  std::string::const_iterator last = std::find(first, s.end(), '>');
  if(last == s.end()) {
    return false;
  }
  std::pair<std::string::const_iterator,
            std::string::const_iterator> p = util::stripIter(first+1, last);
  if(p.first == p.second) {
    return false;
  } else {
    result.uri.assign(p.first, p.second);
  }
  last = std::find(last, s.end(), ';');
  if(last != s.end()) {
    ++last;
  }
  bool ok = false;
  while(1) {
    std::string name, value;
    std::pair<std::string::const_iterator, bool> r =
      util::nextParam(name, value, last, s.end(), ';');
    last = r.first;
    if(!r.second) {
      break;
    }
    if(value.empty()) {
      if(name == "pref") {
        result.pref = true;
      }
    } else {
      if(name == "rel") {
        if(value == "duplicate") {
          ok = true;
        } else {
          ok = false;
        }
      } else if(name == "pri") {
        int32_t priValue;
        if(util::parseIntNoThrow(priValue, value.begin(), value.end())) {
          if(1 <= priValue && priValue <= 999999) {
            result.pri = priValue;
          }
        }
      } else if(name == "geo") {
        util::lowercase(value);
        result.geo = value;
      }
    }
  }
  return ok;
}
} // namespace

// Metalink/HTTP is defined by http://tools.ietf.org/html/rfc6249.
// Link header field is defined by http://tools.ietf.org/html/rfc5988.
void HttpResponse::getMetalinKHttpEntries
(std::vector<MetalinkHttpEntry>& result,
 const SharedHandle<Option>& option) const
{
  std::pair<std::multimap<std::string, std::string>::const_iterator,
            std::multimap<std::string, std::string>::const_iterator> p =
    httpHeader_->getIterator(HttpHeader::LINK);
  for(; p.first != p.second; ++p.first) {
    MetalinkHttpEntry e;
    if(parseMetalinkHttpLink(e, (*p.first).second)) {
      result.push_back(e);
    }
  }
  if(!result.empty()) {
    std::vector<std::string> locs;
    if(option->defined(PREF_METALINK_LOCATION)) {
      util::split(util::toLower(option->get(PREF_METALINK_LOCATION)),
                  std::back_inserter(locs), ",", true);
    }
    for(std::vector<MetalinkHttpEntry>::iterator i = result.begin(),
          eoi = result.end(); i != eoi; ++i) {
      if(std::find(locs.begin(), locs.end(), (*i).geo) != locs.end()) {
        (*i).pri -= 999999;
      }
    }
  }
  std::sort(result.begin(), result.end());
}

#ifdef ENABLE_MESSAGE_DIGEST
// Digest header field is defined by
// http://tools.ietf.org/html/rfc3230.
void HttpResponse::getDigest(std::vector<Checksum>& result) const
{
  using std::swap;
  std::pair<std::multimap<std::string, std::string>::const_iterator,
            std::multimap<std::string, std::string>::const_iterator> p =
    httpHeader_->getIterator(HttpHeader::DIGEST);
  for(; p.first != p.second; ++p.first) {
    const std::string& s = (*p.first).second;
    std::string::const_iterator itr = s.begin();
    while(1) {
      std::string hashType, digest;
      std::pair<std::string::const_iterator, bool> r =
        util::nextParam(hashType, digest, itr, s.end(), ',');
      itr = r.first;
      if(!r.second) {
        break;
      }
      util::lowercase(hashType);
      digest = Base64::decode(digest);
      if(!MessageDigest::supports(hashType) ||
         MessageDigest::getDigestLength(hashType) != digest.size()) {
        continue;
      }
      result.push_back(Checksum(hashType, digest));
    }
  }
  std::sort(result.begin(), result.end(), HashTypeStronger());
  std::vector<Checksum> temp;
  for(std::vector<Checksum>::iterator i = result.begin(),
        eoi = result.end(); i != eoi;) {
    bool ok = true;
    std::vector<Checksum>::iterator j = i+1;
    for(; j != eoi; ++j) {
      if((*i).getHashType() != (*j).getHashType()) {
        break;
      }
      if((*i).getDigest() != (*j).getDigest()) {
        ok = false;
      }
    }
    if(ok) {
      temp.push_back(*i);
    }
    i = j;
  }
  swap(temp, result);
}
#endif // ENABLE_MESSAGE_DIGEST

} // namespace aria2