/// \file http_parser.cpp
/// Holds all code for the HTTP namespace.

#include "auth.h"
#include "defines.h"
#include "encode.h"
#include "http_parser.h"
#include "timing.h"
#include "url.h"
#include "util.h"
#include "json.h"
#include <iomanip>
#include <strings.h>

/// This constructor creates an empty HTTP::Parser, ready for use for either reading or writing.
/// All this constructor does is call HTTP::Parser::Clean().
HTTP::Parser::Parser(){
  headerOnly = false;
  bodyCallback = 0;
  Clean();
  std::stringstream nStr;
  nStr << std::hex << std::setw(16) << std::setfill('0') << (uint64_t)(Util::bootMS());
  cnonce = nStr.str();
}

/// Completely re-initializes the HTTP::Parser, leaving it ready for either reading or writing
/// usage.
void HTTP::Parser::Clean(){
  CleanPreserveHeaders();
  headers.clear();
}

/// Completely re-initializes the HTTP::Parser, leaving it ready for either reading or writing
/// usage.
void HTTP::Parser::CleanPreserveHeaders(){
  seenHeaders = false;
  seenReq = false;
  possiblyComplete = false;
  getChunks = false;
  sendingChunks = false;
  doingChunk = 0;
  bufferChunks = false;
  method = "GET";
  url = "/";
  protocol = "HTTP/1.1";
  body.clear();
  length = 0;
  vars.clear();
}

/// Local-only helper function for use in auth()
/// Returns the string contents of the given val from list
static std::string findValIn(const std::string &list, const std::string &val){
  size_t pos = list.find(val + "=");
  if (pos == std::string::npos){return "";}
  pos += val.size() + 1;
  if (pos >= list.size()){return "";}
  size_t ePos;
  if (list[pos] == '"'){
    ++pos;
    ePos = list.find('"', pos);
    if (ePos == std::string::npos){return "";}
  }else{
    ePos = list.find(',', pos);
  }
  return list.substr(pos, ePos - pos);
}

/// Attempts to send an authentication header with the given name and password. Uses authReq as
/// WWW-Authenticate header.
void HTTP::Parser::auth(const std::string &user, const std::string &pass,
                        const std::string &authReq, const std::string &headerName){
  size_t space = authReq.find(' ');
  if (space == std::string::npos || !user.size() || !pass.size()){
    FAIL_MSG("No authentication possible");
    return;
  }
  std::string meth = authReq.substr(0, space);
  Util::stringToLower(meth);
  if (meth == "basic"){
    SetHeader(headerName, "Basic " + Encodings::Base64::encode(user + ":" + pass));
    return;
  }
  if (meth == "digest"){
    std::string realm = findValIn(authReq, "realm"), nonce = findValIn(authReq, "nonce"),
                opaque = findValIn(authReq, "opaque"), qop = findValIn(authReq, "qop"),
                algo = findValIn(authReq, "algorithm");
    std::string A1 = Secure::md5(user + ":" + realm + ":" + pass);
    if (algo.size() && algo != "MD5"){
      FAIL_MSG("Authorization algorithm %s not implemented", algo.c_str());
      return;
    }
    std::string urlPart;
    if (url.find("://") != std::string::npos && url.substr(0, 4) != "rtsp"){
      HTTP::URL tmpUrl(url);
      urlPart = "/" + tmpUrl.path;
    }else{
      urlPart = url;
    }
    algo = "MD5";
    std::string A2 = Secure::md5(method + ":" + urlPart);
    std::string response;
    static uint32_t nc = 0;
    std::string ncStr;
    if (qop.size()){
      ++nc;
      std::stringstream nHex;
      nHex << std::hex << std::setw(8) << std::setfill('0') << nc;
      ncStr = nHex.str();
      response = Secure::md5(A1 + ":" + nonce + ":" + ncStr + ":" + cnonce + ":auth:" + A2);
    }else{
      response = Secure::md5(A1 + ":" + nonce + ":" + A2);
    }
    std::stringstream rep;
    // username | realm | nonce | digest-uri | response | [ algorithm ] | [cnonce] | [opaque] |
    // [message-qop] | [nonce-count]
    rep << "Digest username=\"" << user << "\", realm=\"" << realm << "\", nonce=\"" << nonce
        << "\", uri=\"" << urlPart << "\", response=\"" << response << "\", algorithm=" + algo;
    if (qop.size()){rep << ", cnonce=\"" << cnonce << "\"";}
    if (opaque.size()){rep << ", opaque=\"" << opaque << "\"";}
    if (qop.size()){rep << ", qop=auth, nc=" << ncStr;}
    SetHeader(headerName, rep.str());
    return;
  }
  FAIL_MSG("No authentication possible, unimplemented method '%s'", meth.c_str());
}

/// Sets the neccesary headers to allow Cross Origin Resource Sharing with all domains.
void HTTP::Parser::setCORSHeaders(){
  SetHeader("Access-Control-Allow-Origin", "*");
  SetHeader("Access-Control-Allow-Credentials", "true");
  SetHeader("Access-Control-Expose-Headers", "*");
  SetHeader("Access-Control-Max-Age", "600");
  SetHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS, HEAD");
  SetHeader("Access-Control-Allow-Headers", "*");
  SetHeader("Access-Control-Request-Method", "GET");
  SetHeader("Access-Control-Request-Headers", "*");
  SetHeader("Cache-Control", "no-cache, no-store, must-revalidate");
  SetHeader("Pragma", "no-cache");
  SetHeader("Expires", "0");
}

/// Returns a string containing a valid HTTP 1.0 or 1.1 request, ready for sending.
/// The request is build from internal variables set before this call is made.
/// To be precise, method, url, protocol, headers and body are used.
/// \return A string containing a valid HTTP 1.0 or 1.1 request, ready for sending.
std::string &HTTP::Parser::BuildRequest(){
  /// \todo Include POST variable handling for vars?
  std::map<std::string, std::string>::iterator it;
  if (protocol.size() < 5 || protocol[4] != '/'){protocol = "HTTP/1.0";}
  if (method != "POST" && vars.size() && url.find('?') == std::string::npos){
    builder = method + " " + Encodings::URL::encode(url, "/:=@[]") + allVars() + " " + protocol + "\r\n";
  }else{
    builder = method + " " + Encodings::URL::encode(url, "/:=@[]") + " " + protocol + "\r\n";
  }
  for (it = headers.begin(); it != headers.end(); it++){
    if ((*it).first != "" && (*it).second != ""){
      builder += (*it).first + ": " + (*it).second + "\r\n";
    }
  }
  builder += "\r\n" + body;
  return builder;
}

/// Creates and sends a valid HTTP 1.0 or 1.1 request.
/// The request is build from internal variables set before this call is made.
/// To be precise, method, url, protocol, headers and body are used.
void HTTP::Parser::SendRequest(Socket::Connection &conn, const std::string &reqbody, bool allAtOnce){
  sendRequest(conn, reqbody.data(), reqbody.size(), allAtOnce);
}

void HTTP::Parser::sendRequest(Socket::Connection &conn, const void *reqbody,
                               const size_t reqbodyLen, bool allAtOnce){
  /// \todo Include GET/POST variable parsing?
  if (allAtOnce){
    /// \TODO Make this less duplicated / more pretty.

    std::map<std::string, std::string>::iterator it;
    if (protocol.size() < 5 || protocol[4] != '/'){protocol = "HTTP/1.0";}
    builder = method + " " + url + " " + protocol + "\r\n";
    if (reqbodyLen){SetHeader("Content-Length", reqbodyLen);}
    for (it = headers.begin(); it != headers.end(); it++){
      if ((*it).first != "" && (*it).second != ""){
        builder += (*it).first + ": " + (*it).second + "\r\n";
      }
    }
    builder += "\r\n";
    if (reqbodyLen){
      if (reqbody){builder += std::string((char *)reqbody, reqbodyLen);}
    }else{
      builder += body;
    }
    conn.SendNow(builder);
    return;
  }
  std::map<std::string, std::string>::iterator it;
  if (protocol.size() < 5 || protocol[4] != '/'){protocol = "HTTP/1.0";}
  builder = method + " " + url + " " + protocol + "\r\n";
  conn.SendNow(builder);
  if (reqbodyLen){SetHeader("Content-Length", reqbodyLen);}
  for (it = headers.begin(); it != headers.end(); it++){
    if ((*it).first != "" && (*it).second != ""){
      builder = (*it).first + ": " + (*it).second + "\r\n";
      conn.SendNow(builder);
    }
  }
  conn.SendNow("\r\n", 2);
  if (reqbodyLen){
    if (reqbody){conn.SendNow((char *)reqbody, reqbodyLen);}
  }else{
    conn.SendNow(body);
  }
}

/// Returns a string containing a valid HTTP 1.0 or 1.1 response, ready for sending.
/// The response is partly build from internal variables set before this call is made.
/// To be precise, protocol, headers and body are used.
/// \param code The HTTP response code. Usually you want 200.
/// \param message The HTTP response message. Usually you want "OK".
/// \return A string containing a valid HTTP 1.0 or 1.1 response, ready for sending.
std::string &HTTP::Parser::BuildResponse(std::string code, std::string message){
  /// \todo Include GET/POST variable parsing?
  std::map<std::string, std::string>::iterator it;
  if (protocol.size() < 5 || protocol[4] != '/'){protocol = "HTTP/1.0";}
  builder = protocol + " " + code + " " + message + "\r\n";
  for (it = headers.begin(); it != headers.end(); it++){
    if ((*it).first != "" && (*it).second != ""){
      if ((*it).first != "Content-Length" || (*it).second != "0"){
        builder += (*it).first + ": " + (*it).second + "\r\n";
      }
    }
  }
  builder += "\r\n";
  builder += body;
  return builder;
}

/// Returns a string containing a valid HTTP 1.0 or 1.1 response, ready for sending.
/// The response is partly build from internal variables set before this call is made.
/// To be precise, protocol, headers and body are used.
/// \return A string containing a valid HTTP 1.0 or 1.1 response, ready for sending.
/// This function calls this->BuildResponse(this->method,this->url)
std::string &HTTP::Parser::BuildResponse(){
  return BuildResponse(method, url);
}

/// Creates and sends a valid HTTP 1.0 or 1.1 response.
/// The response is partly build from internal variables set before this call is made.
/// To be precise, protocol, headers and body are used.
/// This call will attempt to buffer as little as possible and block until the whole request is
/// sent. \param code The HTTP response code. Usually you want 200. \param message The HTTP response
/// message. Usually you want "OK". \param conn The Socket::Connection to send the response over.
void HTTP::Parser::SendResponse(std::string code, std::string message, Socket::Connection &conn){
  /// \todo Include GET/POST variable parsing?
  std::map<std::string, std::string>::iterator it;
  if (protocol.size() < 5 || protocol[4] != '/'){protocol = "HTTP/1.0";}
  builder = protocol + " " + code + " " + message + "\r\n";
  conn.SendNow(builder);
  for (it = headers.begin(); it != headers.end(); it++){
    if ((*it).first != "" && (*it).second != ""){
      if ((*it).first != "Content-Length" || (*it).second != "0"){
        builder = (*it).first + ": " + (*it).second + "\r\n";
        conn.SendNow(builder);
      }
    }
  }
  conn.SendNow("\r\n", 2);
  conn.SendNow(body);
}

/// Creates and sends a valid HTTP 1.0 or 1.1 response, based on the given request.
/// The headers must be set before this call is made.
/// This call sets up chunked transfer encoding if the request was protocol HTTP/1.1, otherwise uses
/// a zero-content-length HTTP/1.0 response. \param code The HTTP response code. Usually you want
/// 200. \param message The HTTP response message. Usually you want "OK". \param request The HTTP
/// request to respond to. \param conn The connection to send over.
void HTTP::Parser::StartResponse(std::string code, std::string message, const HTTP::Parser &request,
                                 Socket::Connection &conn, bool bufferAllChunks){
  std::string prot = request.protocol;
  bool willSendChunks =
      (!bufferAllChunks && request.protocol == "HTTP/1.1" && request.GetHeader("Connection") != "close");
  CleanPreserveHeaders();
  sendingChunks = willSendChunks;
  protocol = prot;
  if (sendingChunks){
    SetHeader("Transfer-Encoding", "chunked");
  }else{
    SetHeader("Connection", "close");
  }
  bufferChunks = bufferAllChunks;
  if (!bufferAllChunks){SendResponse(code, message, conn);}
}

/// Creates and sends a valid HTTP 1.0 or 1.1 response, based on the given request.
/// The headers must be set before this call is made.
/// This call sets up chunked transfer encoding if the request was protocol HTTP/1.1, otherwise uses
/// a zero-content-length HTTP/1.0 response. This call simply calls StartResponse("200", "OK",
/// request, conn) \param request The HTTP request to respond to. \param conn The connection to send
/// over.
void HTTP::Parser::StartResponse(HTTP::Parser &request, Socket::Connection &conn, bool bufferAllChunks){
  StartResponse("200", "OK", request, conn, bufferAllChunks);
}

/// After receiving a header with this object, and after a call with SendResponse/SendRequest with
/// this object, this function call will:
/// - Retrieve all the body from the 'from' Socket::Connection.
/// - Forward those contents as-is to the 'to' Socket::Connection.
/// It blocks until completed or either of the connections reaches an error state.
void HTTP::Parser::Proxy(Socket::Connection &from, Socket::Connection &to){
  if (getChunks){
    unsigned int proxyingChunk = 0;
    while (to.connected() && from.connected()){
      if ((from.Received().size() && (from.Received().size() > 1 || *(from.Received().get().rbegin()) == '\n')) ||
          from.spool()){
        if (proxyingChunk){
          while (proxyingChunk && from.Received().size()){
            unsigned int toappend = from.Received().get().size();
            if (toappend > proxyingChunk){
              toappend = proxyingChunk;
              to.SendNow(from.Received().get().c_str(), toappend);
              from.Received().get().erase(0, toappend);
            }else{
              to.SendNow(from.Received().get());
              from.Received().get().clear();
            }
            proxyingChunk -= toappend;
          }
        }else{
          // Make sure the received data ends in a newline (\n).
          if (*(from.Received().get().rbegin()) != '\n'){
            if (from.Received().size() > 1){
              // make a copy of the first part
              std::string tmp = from.Received().get();
              // clear the first part, wiping it from the partlist
              from.Received().get().clear();
              from.Received().size();
              // take the now first (was second) part, insert the stored part in front of it
              from.Received().get().insert(0, tmp);
            }else{
              Util::sleep(100);
            }
            if (*(from.Received().get().rbegin()) != '\n'){continue;}
          }
          // forward the size and any empty lines
          to.SendNow(from.Received().get());

          std::string tmpA = from.Received().get().substr(0, from.Received().get().size() - 1);
          while (tmpA.find('\r') != std::string::npos){tmpA.erase(tmpA.find('\r'));}
          unsigned int chunkLen = 0;
          if (!tmpA.empty()){
            for (unsigned int i = 0; i < tmpA.size(); ++i){
              chunkLen = (chunkLen << 4) | Encodings::Hex::ord(tmpA[i]);
            }
            if (chunkLen == 0){
              getChunks = false;
              to.SendNow("\r\n", 2);
              return;
            }
            proxyingChunk = chunkLen;
          }
          from.Received().get().clear();
        }
      }else{
        Util::sleep(100);
      }
    }
  }else{
    unsigned int bodyLen = length;
    while (bodyLen > 0 && to.connected() && from.connected()){
      if (from.Received().size() || from.spool()){
        if (from.Received().get().size() <= bodyLen){
          to.SendNow(from.Received().get());
          bodyLen -= from.Received().get().size();
          from.Received().get().clear();
        }else{
          to.SendNow(from.Received().get().c_str(), bodyLen);
          from.Received().get().erase(0, bodyLen);
          bodyLen = 0;
        }
      }else{
        Util::sleep(100);
      }
    }
  }
}

/// Trims any whitespace at the front or back of the string.
/// Used when getting/setting headers.
/// \param s The string to trim. The string itself will be changed, not returned.
void HTTP::Parser::Trim(std::string &s){
  size_t startpos = s.find_first_not_of(" \t");
  size_t endpos = s.find_last_not_of(" \t");
  if ((std::string::npos == startpos) || (std::string::npos == endpos)){
    s = "";
  }else{
    s = s.substr(startpos, endpos - startpos + 1);
  }
}

/// Function that sets the body of a response or request, along with the correct Content-Length
/// header. \param s The string to set the body to.
void HTTP::Parser::SetBody(std::string s){
  body = s;
  SetHeader("Content-Length", s.length());
}

/// Function that sets the body of a response or request, along with the correct Content-Length
/// header. \param buffer The buffer data to set the body to. \param len Length of the buffer data.
void HTTP::Parser::SetBody(const char *buffer, int len){
  body = "";
  body.append(buffer, len);
  SetHeader("Content-Length", len);
}

/// Returns header i, if set.
std::string HTTP::Parser::getUrl(){
  if (url.find('?') != std::string::npos){
    return url.substr(0, url.find('?'));
  }else{
    return url;
  }
}

/// Returns header i, if set.
const std::string &HTTP::Parser::GetHeader(const std::string &i) const{
  if (headers.count(i)){return headers.at(i);}
  for (std::map<std::string, std::string>::const_iterator it = headers.begin(); it != headers.end(); ++it){
    if (it->first.length() != i.length()){continue;}
    if (strncasecmp(it->first.c_str(), i.c_str(), i.length()) == 0){return it->second;}
  }
  // Return empty string if not found
  static const std::string empty;
  return empty;
}

/// Returns header i, if set.
bool HTTP::Parser::hasHeader(const std::string &i) const{
  if (headers.count(i)){return true;}
  for (std::map<std::string, std::string>::const_iterator it = headers.begin(); it != headers.end(); ++it){
    if (it->first.length() != i.length()){continue;}
    if (strncasecmp(it->first.c_str(), i.c_str(), i.length()) == 0){return true;}
  }
  return false;
}

/// Returns POST variable i, if set.
const std::string &HTTP::Parser::GetVar(const std::string &i) const{
  if (vars.count(i)){
    return vars.at(i);
  }else{
    static const std::string empty;
    return empty;
  }
}

std::string HTTP::Parser::allVars(){
  std::string ret;
  if (!vars.size()){return ret;}
  for (std::map<std::string, std::string>::iterator it = vars.begin(); it != vars.end(); ++it){
    if (!it->second.size()){continue;}
    if (ret.size() > 1){
      ret += "&";
    }else{
      ret += "?";
    }
    ret += it->first + "=" + Encodings::URL::encode(it->second);
  }
  return ret;
}

/// Sets header i to string value v.
void HTTP::Parser::SetHeader(std::string i, std::string v){
  Trim(i);
  Trim(v);
  headers[i] = v;
}

void HTTP::Parser::clearHeader(const std::string &i){
  headers.erase(i);
}

/// Sets header i to integer value v.
void HTTP::Parser::SetHeader(std::string i, long long v){
  Trim(i);
  char val[23]; // ints are never bigger than 22 chars as decimal
  sprintf(val, "%lld", v);
  headers[i] = val;
}

/// Sets POST variable i to string value v.
void HTTP::Parser::SetVar(std::string i, std::string v){
  Trim(i);
  Trim(v);
  // only set if there is actually a key
  if (!i.empty()){vars[i] = v;}
}

/// Attempt to read a whole HTTP request or response from a Socket::Connection.
/// If a whole request could be read, it is removed from the front of the socket buffer and true
/// returned. If not, as much as can be interpreted is removed and false returned. \param conn The
/// socket to read from. \return True if a whole request or response was read, false otherwise.
bool HTTP::Parser::Read(Socket::Connection &conn, Util::DataCallback &cb){
  // In this case, we might have a broken connection and need to check if we're done
  if (!conn.Received().size()){
    return (parse(conn.Received().get(), cb) && (!possiblyComplete || !conn || !JSON::Value(url).asInt()));
  }
  while (conn.Received().size()){
    // Make sure the received data ends in a newline (\n).
    while ((!seenHeaders || (getChunks && !doingChunk)) && conn.Received().get().size() &&
           *(conn.Received().get().rbegin()) != '\n'){
      if (conn.Received().size() > 1){
        // make a copy of the first part
        std::string tmp = conn.Received().get();
        // clear the first part, wiping it from the partlist
        conn.Received().get().clear();
        conn.Received().size();
        // take the now first (was second) part, insert the stored part in front of it
        conn.Received().get().insert(0, tmp);
      }else{
        return false;
      }
    }

    // return true if a parse succeeds, and is not a request
    if (parse(conn.Received().get(), cb) && (!possiblyComplete || !conn || !JSON::Value(url).asInt())){
      return true;
    }
  }
  return false;
}// HTTPReader::Read

/// Attempt to read a whole HTTP request or response from a std::string buffer.
/// If a whole request could be read, it is removed from the front of the given buffer and true
/// returned. If not, as much as can be interpreted is removed and false returned. \param strbuf The
/// buffer to read from. \return True if a whole request or response was read, false otherwise.
bool HTTP::Parser::Read(std::string &strbuf){
  return parse(strbuf);
}// HTTPReader::Read

/// Checks download completion percentage.
/// Returns zero if that doesn't make sense at the time or cannot be determined.
uint8_t HTTP::Parser::getPercentage() const{
  if (!seenHeaders || length < 1){return 0;}
  return ((body.length() * 100) / length);
}

/// Attempt to read a whole HTTP response or request from a data buffer.
/// If succesful, fills its own fields with the proper data and removes the response/request
/// from the data buffer.
/// \param HTTPbuffer The data buffer to read from.
/// \return True on success, false otherwise.
bool HTTP::Parser::parse(std::string &HTTPbuffer, Util::DataCallback &cb){
  size_t f;
  std::string tmpA, tmpB, tmpC;
  /// \todo Make this not resize HTTPbuffer in parts, but read all at once and then remove the
  /// entire request, like doxygen claims it does?
  while (!HTTPbuffer.empty()){
    if (!seenHeaders){
      f = HTTPbuffer.find('\n');
      if (f == std::string::npos) return false;
      tmpA = HTTPbuffer.substr(0, f);
      if (f + 1 == HTTPbuffer.size()){
        HTTPbuffer.clear();
      }else{
        HTTPbuffer.erase(0, f + 1);
      }
      while (tmpA.find('\r') != std::string::npos){tmpA.erase(tmpA.find('\r'));}
      if (!seenReq){
        seenReq = true;
        f = tmpA.find(' ');
        if (f != std::string::npos){
          if (tmpA.substr(0, 4) == "HTTP"){
            protocol = tmpA.substr(0, f);
            tmpA.erase(0, f + 1);
            f = tmpA.find(' ');
            if (f != std::string::npos){
              url = tmpA.substr(0, f);
              tmpA.erase(0, f + 1);
              method = tmpA;
              if (url.find('?') != std::string::npos){
                parseVars(url.substr(url.find('?') + 1), vars); // parse GET variables
                url.erase(url.find('?'));
              }
              url = Encodings::URL::decode(url);
            }else{
              seenReq = false;
            }
          }else{
            method = tmpA.substr(0, f);
            tmpA.erase(0, f + 1);
            f = tmpA.find(' ');
            if (f != std::string::npos){
              url = tmpA.substr(0, f);
              tmpA.erase(0, f + 1);
              protocol = tmpA;
              if (url.find('?') != std::string::npos){
                parseVars(url.substr(url.find('?') + 1), vars); // parse GET variables
                url.erase(url.find('?'));
              }
              url = Encodings::URL::decode(url);
            }else{
              seenReq = false;
            }
          }
        }else{
          seenReq = false;
        }
      }else{
        if (tmpA.size() == 0){
          seenHeaders = true;
          body.clear();
          if (GetHeader("Content-Length") != ""){
            length = atoi(GetHeader("Content-Length").c_str());
            if (!bodyCallback && (&cb == &Util::defaultDataCallback) && body.capacity() < length){
              body.reserve(length);
            }
          }
          if (GetHeader("Transfer-Encoding") == "chunked"){
            getChunks = true;
            doingChunk = 0;
          }
        }else{
          f = tmpA.find(':');
          if (f == std::string::npos) continue;
          tmpB = tmpA.substr(0, f);
          tmpC = tmpA.substr(f + 1);
          SetHeader(tmpB, tmpC);
        }
      }
    }
    if (seenHeaders){
      if (headerOnly){return true;}
      //Check if we have a response code that may never have a body
      if (url.size() && url[0] >= '0' && url[0] <= '9'){
        unsigned int code = atoi(url.data());
        if ((code >= 100 && code < 200) || code == 204 || code == 304){return true;}
      }
      if (length > 0 && !getChunks){
        unsigned int toappend = length - body.length();

        // limit the amount of bytes that will be appended to the amount there
        // is available
        if (toappend > HTTPbuffer.size()){toappend = HTTPbuffer.size();}

        if (toappend > 0){
          bool shouldAppend = true;
          // check if pointer callback function is set and run callback. remove partial data from buffer
          if (bodyCallback){
            bodyCallback(HTTPbuffer.data(), toappend);
            length -= toappend;
            shouldAppend = false;
          }

          // check if reference callback function is set and run callback. remove partial data from buffer
          if (&cb != &Util::defaultDataCallback){
            cb.dataCallback(HTTPbuffer.data(), toappend);
            length -= toappend;
            shouldAppend = false;
          }

          if (shouldAppend){body.append(HTTPbuffer, 0, toappend);}
          HTTPbuffer.erase(0, toappend);
          currentLength += toappend;
        }
        if (length == body.length()){
          // parse POST variables
          if (method == "POST"){parseVars(body, vars);}
          return true;
        }else{
          return false;
        }
      }else{
        if (getChunks){
          currentLength += HTTPbuffer.size();
          if (doingChunk){
            unsigned int toappend = HTTPbuffer.size();
            if (toappend > doingChunk){toappend = doingChunk;}

            bool shouldAppend = true;
            if (bodyCallback){
              bodyCallback(HTTPbuffer.data(), toappend);
              shouldAppend = false;
            }

            if (&cb != &Util::defaultDataCallback){
              cb.dataCallback(HTTPbuffer.data(), toappend);
              shouldAppend = false;
            }

            if (shouldAppend){body.append(HTTPbuffer, 0, toappend);}
            HTTPbuffer.erase(0, toappend);
            doingChunk -= toappend;
          }else{
            f = HTTPbuffer.find('\n');
            if (f == std::string::npos){return false;}
            tmpA = HTTPbuffer.substr(0, f);
            while (tmpA.find('\r') != std::string::npos){tmpA.erase(tmpA.find('\r'));}
            unsigned int chunkLen = 0;
            if (!tmpA.empty()){
              for (unsigned int i = 0; i < tmpA.size(); ++i){
                chunkLen = (chunkLen << 4) | Encodings::Hex::ord(tmpA[i]);
              }
              if (chunkLen == 0){
                getChunks = false;
                return true;
              }
              doingChunk = chunkLen;
            }
            if (f + 1 == HTTPbuffer.size()){
              HTTPbuffer.clear();
            }else{
              HTTPbuffer.erase(0, f + 1);
            }
          }
          return false;
        }else{
          if (protocol.substr(0, 4) == "RTSP" || method.substr(0, 4) == "RTSP"){return true;}
          unsigned int toappend = HTTPbuffer.size();
          bool shouldAppend = true;
          if (bodyCallback){
            bodyCallback(HTTPbuffer.data(), toappend);
            shouldAppend = false;
          }

          if (&cb != &Util::defaultDataCallback){
            cb.dataCallback(HTTPbuffer.data(), toappend);
            shouldAppend = false;
          }

          if (shouldAppend){body.append(HTTPbuffer, 0, toappend);}
          HTTPbuffer.erase(0, toappend);

          // return true if there is no body, otherwise we only stop when the connection is dropped
          possiblyComplete = true;
          return true;
        }
      }
    }
  }
  return possiblyComplete; // empty input
}// HTTPReader::parse

/// HTTP variable parser to std::map<std::string, std::string> structure.
/// Reads variables from data, decodes and stores them to storage.
void HTTP::parseVars(const std::string &data, std::map<std::string, std::string> &storage){
  std::string varname;
  std::string varval;
  // position where a part starts (e.g. after &)
  size_t pos = 0;
  while (pos < data.length()){
    size_t nextpos = data.find('&', pos);
    if (nextpos == std::string::npos){nextpos = data.length();}
    size_t eq_pos = data.find('=', pos);
    if (eq_pos < nextpos){
      // there is a key and value
      varname = data.substr(pos, eq_pos - pos);
      varval = data.substr(eq_pos + 1, nextpos - eq_pos - 1);
    }else{
      // no value, only a key
      varname = data.substr(pos, nextpos - pos);
      varval.clear();
    }
    if (varname.size()){
      DONTEVEN_MSG("Found key:value pair '%s:%s'", varname.c_str(), varval.c_str());
      storage[Encodings::URL::decode(varname)] = Encodings::URL::decode(varval);
    }
    if (nextpos == std::string::npos){
      // in case the string is gigantic
      break;
    }
    // erase &
    pos = nextpos + 1;
  }
}

/// Sends a string in chunked format if protocol is HTTP/1.1, sends as-is otherwise.
/// \param bodypart The data to send.
/// \param conn The connection to use for sending.
void HTTP::Parser::Chunkify(const std::string &bodypart, Socket::Connection &conn){
  Chunkify(bodypart.c_str(), bodypart.size(), conn);
}

/// Sends a string in chunked format if protocol is HTTP/1.1, sends as-is otherwise.
/// \param data The data to send.
/// \param size The size of the data to send.
/// \param conn The connection to use for sending.
void HTTP::Parser::Chunkify(const char *data, unsigned int size, Socket::Connection &conn){
  static char hexa[] = "0123456789abcdef";
  if (bufferChunks){
    if (size){
      body.append(data, size);
    }else{
      SetHeader("Content-Length", body.length());
      SendResponse("200", "OK", conn);
      Clean();
    }
    return;
  }
  if (sendingChunks){
    // prepend the chunk size and \r\n
    if (!size){conn.SendNow("0\r\n\r\n", 5);}
    size_t offset = 8;
    unsigned int t_size = size;
    char len[] = "\000\000\000\000\000\000\0000\r\n";
    while (t_size && offset < 9){
      len[--offset] = hexa[t_size & 0xf];
      t_size >>= 4;
    }
    conn.SendNow(len + offset, 10 - offset);
    // send the chunk itself
    conn.SendNow(data, size);
    // append \r\n
    conn.SendNow("\r\n", 2);
  }else{
    // just send the chunk itself
    conn.SendNow(data, size);
    // close the connection if this was the end of the file
    if (!size){
      conn.close();
      Clean();
    }
  }
}