/*
 * Copyright (C) 2012 Tommi Maekitalo
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * As a special exception, you may use this file as part of a free
 * software library without restriction. Specifically, if other files
 * instantiate templates or use macros or inline functions from this
 * file, or you compile this file and link it with other files to
 * produce an executable, this file does not by itself cause the
 * resulting executable to be covered by the GNU General Public
 * License. This exception does not however invalidate any other
 * reasons why the executable file might be covered by the GNU Library
 * General Public License.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */


#include <tnt/component.h>
#include <tnt/componentfactory.h>
#include <tnt/ecpp.h>
#include <tnt/httprequest.h>
#include <tnt/httpreply.h>
#include <tnt/http.h>
#include <cxxtools/http/client.h>
#include <cxxtools/http/request.h>
#include <cxxtools/http/reply.h>
#include <cxxtools/net/uri.h>
#include <cxxtools/log.h>
#include <cxxtools/split.h>
#include <strings.h>
#include <vector>
#include <iterator>

log_define("tntnet.proxy")

namespace tnt
{
  class Urlmapper;
  class Comploader;

  ////////////////////////////////////////////////////////////////////////
  // component declaration
  //
  class Proxy : public tnt::EcppComponent
  {
    friend class ProxyFactory;

    public:
      Proxy(const tnt::Compident& ci, const tnt::Urlmapper& um, tnt::Comploader& cl)
        : EcppComponent(ci, um, cl)
        { }

      virtual unsigned operator() (tnt::HttpRequest& request, tnt::HttpReply& reply, tnt::QueryParams& qparam);
  };

  ////////////////////////////////////////////////////////////////////////
  // factory
  //
  class ProxyFactory : public tnt::ComponentFactory
  {
    public:
      ProxyFactory(const std::string& componentName)
        : tnt::ComponentFactory(componentName)
        { }

      virtual tnt::Component* doCreate(const tnt::Compident& ci, const tnt::Urlmapper& um, tnt::Comploader& cl);
  };

  tnt::Component* ProxyFactory::doCreate(const tnt::Compident& ci, const tnt::Urlmapper& um, tnt::Comploader& cl)
    { return new Proxy(ci, um, cl); }

  static ProxyFactory proxyFactory("proxy");

  ////////////////////////////////////////////////////////////////////////
  // component definition
  //
  unsigned Proxy::operator() (tnt::HttpRequest& request, tnt::HttpReply& reply, tnt::QueryParams& qparam)
  {
    std::string uriStr = request.getArg("uri");
    if (uriStr.empty())
        uriStr = request.getArg(0);  // for compatibility

    if (uriStr.empty())
    {
      log_error("proxy uri missing in configuration");
      throw std::runtime_error("proxy uri missing in configuration");
    }

    TNT_THREAD_COMPONENT_VAR(std::string, currentProxyHost, ());
    TNT_THREAD_COMPONENT_VAR(unsigned short, currentProxyPort, ());
    TNT_THREAD_COMPONENT_VAR(cxxtools::http::Client, client, ());

    cxxtools::net::Uri uri(uriStr);

    std::string url = uri.path();
    bool urlEndsWithSlash = !url.empty() && url[url.size()-1] == '/';
    bool pathInfoStartsWithSlash = !request.getPathInfo().empty() && request.getPathInfo()[0] == '/';

    if (urlEndsWithSlash
      && pathInfoStartsWithSlash)
    {
      // Avoid double slash, if getPathInfo starts with '/' (which is normally the case).
      url.erase (url.size()-1, 1);
    }
    else if (!urlEndsWithSlash
      && !pathInfoStartsWithSlash)
    {
      url += '/';
    }

    url += request.getPathInfo();
    if (!request.getQueryString().empty())
    {
      url += '?';
      url += request.getQueryString();
    }

    if (currentProxyHost != uri.host() || currentProxyPort != uri.port())
    {
      log_debug("connect to " << uri.host() << ':' << uri.port());
      client.connect(uri.host(), uri.port());
      currentProxyHost = uri.host();
      currentProxyPort = uri.port();
    }
    else
      log_debug("already connected to " << uri.host() << ':' << uri.port());

    log_info("get file " << url << " qparam=" << qparam.getUrl() << " from " << uri.host() << ':' << uri.port() << " body size=" << request.getBody().size());

    // set up client request
    cxxtools::http::Request clientRequest(url);

    clientRequest.method(request.getMethod());

    clientRequest.body() << request.getBody();

    const char* value;

    clientRequest.setHeader ("Host", uri.host().c_str());

    std::string peerIp = request.getPeerIp();
    clientRequest.setHeader ("X-Real-IP", peerIp.c_str());
    clientRequest.addHeader ("X-Forwarded-For", peerIp.c_str());

    value = request.getHeader(tnt::httpheader::contentType, 0);
    if (value)
      clientRequest.header().setHeader("Content-Type", value);

    value = request.getHeader(tnt::httpheader::cookie, 0);
    if (value)
      clientRequest.header().setHeader("Cookie", value);

    value = request.getHeader(tnt::httpheader::authorization, 0);
    if (value)
      clientRequest.header().setHeader("Authorization", value);

    value = request.getHeader(tnt::httpheader::ifModifiedSince, 0);
    if (value)
      clientRequest.header().setHeader("If-Modified-Since", value);

    std::vector<std::string> forwardHeaders;
    log_debug("forwardHeaders: \"" << request.getArg("forwardHeaders") << '"');
    cxxtools::split(',', request.getArg("forwardHeaders"), std::back_inserter(forwardHeaders));
    for (unsigned n = 0; n < forwardHeaders.size(); ++n)
    {
      log_debug("forward header \"" << forwardHeaders[n] << '"');
      value = request.getHeader((forwardHeaders[n] + ':').c_str(), 0);
      if (value)
      {
        log_debug("value \"" << value << '"');
        clientRequest.header().setHeader(forwardHeaders[n].c_str(), value);
      }
    }

    // execute client request
    client.execute(clientRequest);

    // retrieve result
    std::string body = client.readBody();

    unsigned httpReturnCode = client.header().httpReturnCode();
    const char* contentType = client.header().getHeader("Content-type");

    for (cxxtools::http::MessageHeader::const_iterator it = client.header().begin();
        it != client.header().end(); ++it)
    {
      if (strcasecmp(it->first, "Set-Cookie") == 0)
      {
        log_info("cookie: " << it->first << " value: " << it->second);
        reply.setHeader(tnt::httpheader::setCookie, it->second, false);
      }
    }

    value = client.header().getHeader ("p3p");
    if (value)
      reply.setHeader("p3p:", value);

    value = client.header().getHeader("Cache-Control");
    if (value)
      reply.setHeader(tnt::httpheader::cacheControl, value);

    value = client.header().getHeader("Expires");
    if (value)
      reply.setHeader(tnt::httpheader::expires, value);

    value = client.header().getHeader("Last-Modified");
    if (value)
      reply.setHeader(tnt::httpheader::lastModified, value);

    value = client.header().getHeader("Location");
    if (value)
      reply.setHeader(tnt::httpheader::location, value);

    value = client.header().getHeader("Content-Disposition");
    if (value)
      reply.setHeader("Content-Disposition:", value);

    value = client.header().getHeader("WWW-Authenticate");
    if (value)
      reply.setHeader(tnt::httpheader::wwwAuthenticate, value);

    log_debug("got file " << request.getPathInfo() << " with http return code=" << httpReturnCode << " content type=" << (contentType ? contentType : "NULL"));

    if (httpReturnCode == HTTP_NOT_FOUND)
      return DECLINED;

    if (contentType)
      reply.setContentType(contentType);

    reply.out() << body;

    return httpReturnCode;
  }
}