#include "uscxml/ioprocessor/basichttp/libevent/EventIOProcessor.h"
#include "uscxml/Message.h"
#include <iostream>
#include <event2/dns.h>
#include <event2/buffer.h>
#include <event2/keyvalq_struct.h>

#include <string.h>

#include <io/uri.hpp>
#include <glog/logging.h>

#include <netdb.h>
#include <arpa/inet.h>

namespace uscxml {
namespace io {
namespace libevent {

// see http://www.w3.org/TR/scxml/#BasicHTTPEventProcessor

EventIOProcessor::EventIOProcessor() {
}

EventIOProcessor::~EventIOProcessor() {
  _eventQueue.stop();
  EventIOServer* httpServer = EventIOServer::getInstance();
  httpServer->unregisterProcessor(this);
}

IOProcessor* EventIOProcessor::create(Interpreter* interpreter) {
  EventIOProcessor* io = new EventIOProcessor();
  io->_interpreter = interpreter;

  io->_dns = evdns_base_new(io->_eventQueue._eventLoop, 1);
  assert(io->_dns);
  assert(evdns_base_count_nameservers(io->_dns) > 0);
  
  // register at http server
  EventIOServer* httpServer = EventIOServer::getInstance();
  httpServer->registerProcessor(io);
  
  io->start();
  return io;
}

void EventIOProcessor::start() {
  _eventQueue.start();
}

void EventIOProcessor::send(SendRequest& req) {
  // I cant figure out how to copy the reference into the struct :(
  _sendData[req.sendid].req = req;
  _sendData[req.sendid].ioProcessor = this;

  if (req.delayMs > 0) {
    LOG(INFO) << "Enqueing HTTP send request";
    _eventQueue.addEvent(req.sendid, EventIOProcessor::httpMakeSendReq, req.delayMs, &_sendData[req.sendid]);
  } else {
    LOG(INFO) << "Sending HTTP send request";
    EventIOProcessor::httpMakeSendReq(&_sendData[req.sendid], req.sendid);
  }
}

void EventIOProcessor::httpMakeSendReq(void* userdata, std::string eventName) {
  SendData* sendData = ((SendData*)userdata);
  EventIOProcessor* THIS = sendData->ioProcessor;
  int err = 0;
  char uriBuf[1024];
  
  struct evhttp_uri* targetURI = evhttp_uri_parse(sendData->req.target.c_str());
  if (evhttp_uri_get_port(targetURI) == 0)
    evhttp_uri_set_port(targetURI, 80);
  const char* hostName = evhttp_uri_get_host(targetURI);

  // use synchronous dns resolving for multicast dns
  if(strlen(hostName) >= strlen(".local")) {
    if(strcmp(hostName + strlen(hostName) - strlen(".local"), ".local") == 0) {
      evhttp_uri_set_host(targetURI, EventIOServer::syncResolve(hostName).c_str());
    }
  }
  evhttp_uri_join(targetURI, uriBuf, 1024);

  LOG(INFO) << "URI for send request: " << uriBuf << std::endl;
  
  std::stringstream ssEndPoint;
  ssEndPoint << evhttp_uri_get_host(targetURI) << ":" << evhttp_uri_get_port(targetURI);
  std::string endPoint = ssEndPoint.str();

  std::stringstream ssLocalURI;
  ssLocalURI << evhttp_uri_get_path(targetURI) << evhttp_uri_get_fragment(targetURI);
  std::string localURI = ssLocalURI.str();

  if (THIS->_httpConnections.find(endPoint) == THIS->_httpConnections.end())
    THIS->_httpConnections[endPoint] = evhttp_connection_base_new(THIS->_eventQueue._eventLoop, THIS->_dns, evhttp_uri_get_host(targetURI), evhttp_uri_get_port(targetURI));

  struct evhttp_connection* httpConn = THIS->_httpConnections[endPoint];
  struct evhttp_request* httpReq = evhttp_request_new(EventIOProcessor::httpSendReqDone, userdata);
  
#if 0
  // event name
  if (sendData->req.event.size() > 0) {
    evhttp_add_header(evhttp_request_get_output_headers(httpReq), "_scxmleventname", evhttp_encode_uri(sendData->req.event.c_str()));
  }
  
  // event namelist
  if (sendData->req.namelist.size() > 0) {
    std::map<std::string, std::string>::iterator namelistIter = sendData->req.namelist.begin();
    while (namelistIter != sendData->req.namelist.end()) {
      evhttp_add_header(evhttp_request_get_output_headers(httpReq),
                        namelistIter->first.c_str(),
                        evhttp_encode_uri(namelistIter->second.c_str()));
      namelistIter++;
    }
  }
  
  // event params
  if (sendData->req.params.size() > 0) {
    std::map<std::string, std::string>::iterator paramIter = sendData->req.params.begin();
    while (paramIter != sendData->req.params.end()) {
      evhttp_add_header(evhttp_request_get_output_headers(httpReq),
                        paramIter->first.c_str(),
                        evhttp_encode_uri(paramIter->second.c_str()));
      paramIter++;
    }
  }
  
  // content
  if (sendData->req.content.size() > 0)
    evbuffer_add(evhttp_request_get_output_buffer(httpReq), sendData->req.content.c_str(), sendData->req.content.size());
#endif

  evhttp_add_header(evhttp_request_get_output_headers(httpReq), "_scxmleventstruct", evhttp_encode_uri(sendData->req.toXMLString().c_str()));

  
  THIS->_httpRequests[sendData->req.sendid] = httpReq;
  err = evhttp_make_request(httpConn,
                            httpReq,
                            EVHTTP_REQ_POST, localURI.c_str());
  if (err) {
    LOG(ERROR) << "Could not make http request to " << sendData->req.target;
  }
}

void EventIOProcessor::httpRecvReq(struct evhttp_request *req, void *arg) {
  
	const char *cmdtype;
	struct evkeyvalq *headers;
	struct evkeyval *header;
	struct evbuffer *buf;

  switch (evhttp_request_get_command(req)) {
    case EVHTTP_REQ_GET: cmdtype = "GET"; break;
    case EVHTTP_REQ_POST: cmdtype = "POST"; break;
    case EVHTTP_REQ_HEAD: cmdtype = "HEAD"; break;
    case EVHTTP_REQ_PUT: cmdtype = "PUT"; break;
    case EVHTTP_REQ_DELETE: cmdtype = "DELETE"; break;
    case EVHTTP_REQ_OPTIONS: cmdtype = "OPTIONS"; break;
    case EVHTTP_REQ_TRACE: cmdtype = "TRACE"; break;
    case EVHTTP_REQ_CONNECT: cmdtype = "CONNECT"; break;
    case EVHTTP_REQ_PATCH: cmdtype = "PATCH"; break;
    default: cmdtype = "unknown"; break;
	}

  Event reqEvent;
  reqEvent.type = Event::EXTERNAL;

  // map headers to event structure
  headers = evhttp_request_get_input_headers(req);
	for (header = headers->tqh_first; header;
       header = header->next.tqe_next) {
//    std::cout << "Header: " << header->key << std::endl;
//    std::cout << "Value: " << evhttp_decode_uri(header->value) << std::endl;
    if (boost::iequals("_scxmleventstruct", header->key)) {
      reqEvent = Event::fromXML(evhttp_decode_uri(header->value));
      break;
    } else if (boost::iequals("_scxmleventname", header->key)) {
      reqEvent.name = evhttp_decode_uri(header->value);
    } else {
      reqEvent.compound[header->key] = Data(evhttp_decode_uri(header->value), Data::VERBATIM);
    }
	}

  // get content into event
  std::string content;
	buf = evhttp_request_get_input_buffer(req);
	while (evbuffer_get_length(buf)) {
		int n;
		char cbuf[128];
		n = evbuffer_remove(buf, cbuf, sizeof(buf)-1);
		if (n > 0) {
      content.append(cbuf, n);
    }
	}
  reqEvent.compound["content"] = Data(content, Data::VERBATIM);
  
  EventIOProcessor* THIS = (EventIOProcessor*)arg;
  THIS->_interpreter->receive(reqEvent);
  
	evhttp_send_reply(req, 200, "OK", NULL);
}

void EventIOProcessor::httpSendReqDone(struct evhttp_request *req, void *cb_arg) {
  if (req) {
    LOG(INFO) << "got return code " << evhttp_request_get_response_code(req) << std::endl;
  }
}

void EventIOProcessor::invoke(InvokeRequest& req) {
  
}
void EventIOProcessor::cancel(const std::string sendId) {
  
}

EventIOServer::EventIOServer(unsigned short port) {
  _port = port;
  _base = event_base_new();
  _http = evhttp_new(_base);
  _handle = NULL;
  while((_handle = evhttp_bind_socket_with_handle(_http, INADDR_ANY, _port)) == NULL) {
    _port++;
  }
  determineAddress();
}

EventIOServer::~EventIOServer() {
}

EventIOServer* EventIOServer::_instance = NULL;
tthread::recursive_mutex EventIOServer::_instanceMutex;

EventIOServer* EventIOServer::getInstance() {
  tthread::lock_guard<tthread::recursive_mutex> lock(_instanceMutex);
  if (_instance == NULL) {
    _instance = new EventIOServer(8080);
    _instance->start();
  }
  return _instance;
}

void EventIOServer::registerProcessor(EventIOProcessor* processor) {
  EventIOServer* THIS = getInstance();
  tthread::lock_guard<tthread::recursive_mutex> lock(THIS->_mutex);
  
  /**
   * Determine path for interpreter.
   *
   * If the interpreter has a name and it is not yet taken, choose it as the path 
   * for requests. If the interpreters name path is already taken, append digits
   * until we have an available path.
   *
   * If the interpreter does not specify a name, take its sessionid.
   */
  
  std::string path = processor->_interpreter->getName();
  if (path.size() == 0) {
    path = processor->_interpreter->getSessionId();
  }
  assert(path.size() > 0);
  
  std::stringstream actualPath(path);
  int i = 1;
  while(THIS->_processors.find(actualPath.str()) != THIS->_processors.end()) {
    actualPath.str(std::string());
    actualPath.clear();
    actualPath << path << ++i;
  }
  
  std::stringstream processorURL;
  processorURL << "http://" << THIS->_address << ":" << THIS->_port << "/" << actualPath.str();
  
  THIS->_processors[actualPath.str()] = processor;
  processor->setURL(processorURL.str());
  
  evhttp_set_cb(THIS->_http, ("/" + actualPath.str()).c_str(), EventIOProcessor::httpRecvReq, processor);
//  evhttp_set_cb(THIS->_http, "/", EventIOProcessor::httpRecvReq, processor);
//  evhttp_set_gencb(THIS->_http, EventIOProcessor::httpRecvReq, NULL);
}

void EventIOServer::unregisterProcessor(EventIOProcessor* processor) {
  EventIOServer* THIS = getInstance();
  tthread::lock_guard<tthread::recursive_mutex> lock(THIS->_mutex);
  evhttp_del_cb(THIS->_http, processor->getURL().c_str());
}
  
void EventIOServer::start() {
  _isRunning = true;
  _thread = new tthread::thread(EventIOServer::run, this);
}

void EventIOServer::run(void* instance) {
  EventIOServer* THIS = (EventIOServer*)instance;
  while(THIS->_isRunning) {
    LOG(INFO) << "Dispatching HTTP Server" << std::endl;
    event_base_dispatch(THIS->_base);
  }
  LOG(INFO) << "HTTP Server stopped" << std::endl;
}

std::string EventIOServer::syncResolve(const std::string& hostname) {
  struct hostent *he;
  struct in_addr **addr_list;
  int i;

  if ( (he = gethostbyname( hostname.c_str() ) ) != NULL) {
    addr_list = (struct in_addr **) he->h_addr_list;
    for(i = 0; addr_list[i] != NULL; i++) {
      return std::string(inet_ntoa(*addr_list[i]));
    }
  }
  return "";
}
  
void EventIOServer::determineAddress() {

  char hostname[1024];
  gethostname(hostname, 1024);
  _address = std::string(hostname);
  
#if 0
  struct sockaddr_storage ss;
  evutil_socket_t fd;
  ev_socklen_t socklen = sizeof(ss);
  char addrbuf[128];

  void *inaddr;
  const char *addr;
  int got_port = -1;
  fd = evhttp_bound_socket_get_fd(_handle);
  memset(&ss, 0, sizeof(ss));
  if (getsockname(fd, (struct sockaddr *)&ss, &socklen)) {
    perror("getsockname() failed");
    return;
  }
  
  if (ss.ss_family == AF_INET) {
    got_port = ntohs(((struct sockaddr_in*)&ss)->sin_port);
    inaddr = &((struct sockaddr_in*)&ss)->sin_addr;
  } else if (ss.ss_family == AF_INET6) {
    got_port = ntohs(((struct sockaddr_in6*)&ss)->sin6_port);
    inaddr = &((struct sockaddr_in6*)&ss)->sin6_addr;
  } else {
    fprintf(stderr, "Weird address family %d\n",
            ss.ss_family);
    return;
  }
  addr = evutil_inet_ntop(ss.ss_family, inaddr, addrbuf,
                          sizeof(addrbuf));
  if (addr) {
    _address = std::string(addr);
  } else {
    fprintf(stderr, "evutil_inet_ntop failed\n");
    return;
  }
#endif
}

}
}
}