/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/***************************************************************************
 *            server.cc
 *
 *  Wed Aug 22 12:16:03 CEST 2007
 *  Copyright 2007 Bent Bisballe Nyeng
 *  deva@aasimon.org
 ****************************************************************************/

/*
 *  This file is part of Pracro.
 *
 *  Pracro 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.
 *
 *  Pracro 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 Pracro; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
 */
#include "server.h"

#include <config.h>

#include "tcpsocket.h"
#include <errno.h>

#include <stdlib.h>

// For fork
#include <sys/types.h>
#include <unistd.h>
#include <string.h>

#include <microhttpd.h>

#include "configuration.h"
#include "transaction.h"
#include "transactionparser.h"
#include "database.h"
#include "log.h"
#include "environment.h"
#include "transactionhandler.h"
#include "connectionpool.h"
#include "session.h"
#include "xml_encode_decode.h"

static std::string error_box(std::string message)
{
  std::string errorbox =
    "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
    "<pracro version=\"1.0\">\n"
    "  <error>" + message + "</error>\n"
    "</pracro>\n";
  return errorbox;
}

static std::string handleConnection(const std::string &data,
                                    Environment &env,
                                    std::string &sessionid,
                                    bool sessioncommit)
{
  std::string res;

  Session *session = NULL;
  if(sessionid == "") {
    session = env.sessions.newSession();
  } else {
    session = env.sessions.session(sessionid);
    if(session == NULL) session = env.sessions.newSession();
  }

  if(session == NULL) {
    PRACRO_ERR(server, "New session could not be created.");
    return error_box(xml_encode("New session could not be created."));
  }

  sessionid = session->id();

  {
    SessionAutolock lock(*session);

    if(data.length()) {
      Transaction transaction;
      TransactionParser parser(&transaction);
      
      if(!parser.parse(data.c_str(), data.length())) {
        PRACRO_ERR(server, "Failed to parse data!\n");
        PRACRO_ERR(server, "DATA:[[%s]]\n", data.c_str());
        res = error_box(xml_encode("XML Parse error."));
      } else {
        res = handleTransaction(transaction, env, *session);
      }
    }

  }

  if(sessioncommit) {
    session->commit();
    env.sessions.deleteSession(session->id());
  }

  return res;
}

struct condata {
  std::map<std::string, std::string> headers;
  std::string data;
  size_t data_size;
  std::string url;
  std::string method;
  std::string version;
};

//static std::map<struct MHD_Connection *, struct condata> condata;

static int handle_request_callback(void *cls,
                                   struct MHD_Connection *con,
                                   const char *url,
                                   const char *method,
                                   const char *version,
                                   const char *data,
                                   unsigned int *data_size,
                                   void **con_cls)
{
  PRACRO_DEBUG(httpd, "handle_request_callback con:%p condata:%p\n",
               con, *con_cls);

  // Test for new connection
  if(*con_cls == NULL) {
    PRACRO_DEBUG(httpd,
                 "handle_request(url=\"%s\", method=\"%s\","
                 " version=\"%s\", data_size=\"%d\")\n",
                 url, method, version, *data_size);

    struct condata *cd = new struct condata;
    cd->url = url;
    cd->method = method;
    cd->version = version;
    cd->data_size = 0;
    cd->data = "";

    const char *sid = MHD_lookup_connection_value(con, MHD_HEADER_KIND,
                                                  "SessionID");
    if(sid) cd->headers["SessionID"] = sid;

    const char *scm = MHD_lookup_connection_value(con, MHD_HEADER_KIND,
                                                  "SessionCommit");
    if(scm) cd->headers["SessionCommit"] = scm;

    const char *csz = MHD_lookup_connection_value(con, MHD_HEADER_KIND,
                                                  "Content-Length");
    if(csz) {
      cd->headers["Content-Length"] = csz;
      cd->data_size = atol(csz);
      PRACRO_DEBUG(httpd, "Content-Length: %s (%d)\n", csz, cd->data_size);
    }

    *con_cls = cd;
  }

  struct condata *cd = (struct condata*)*con_cls;
  cd->data.append(data, *data_size);

  int ret = MHD_YES;

  PRACRO_DEBUG(httpd, "Waiting for %d bytes of data. Got %d (total %d)\n",
               cd->data_size, *data_size, cd->data.length());

  if(cd->data.length() >= cd->data_size) {

    Environment *env = (Environment *)cls;

    const char *sid = MHD_lookup_connection_value(con, MHD_HEADER_KIND,
                                                  "SessionID");
    std::string sessionid;
    if(sid) sessionid = sid;
    
    const char *sessioncommit =
      MHD_lookup_connection_value(con, MHD_HEADER_KIND, "SessionCommit");
    
    PRACRO_DEBUG(httpd, "Starting to handle SessionID: %s%s\n",
                 sessionid.c_str(),
                 sessioncommit != NULL?" COMMIT":"");
    
    PRACRO_DEBUG(httpd, "Data: [%s]\n", cd->data.c_str());
    
    std::string reply =
      handleConnection(cd->data, *env, sessionid, sessioncommit != NULL);
    
    struct MHD_Response *rsp =
      MHD_create_response_from_data(reply.length(), (char*)reply.c_str(),
                                    MHD_NO, MHD_YES);
    MHD_add_response_header(rsp, MHD_HTTP_HEADER_CONTENT_TYPE,
                            "text/plain; charset=UTF-8");
    
    if(sessionid != "") {
      MHD_add_response_header(rsp, "SessionID", sessionid.c_str());
    }
    
    ret = MHD_queue_response(con, MHD_HTTP_OK, rsp);
    MHD_destroy_response(rsp);
    
    PRACRO_DEBUG(httpd, "Finished handling SessionID: %s%s\n",
                 sessionid.c_str(),
                 sessioncommit != NULL?" COMMIT":"");


    delete cd;
    *con_cls = NULL;

  }

  *data_size = 0;

  return ret;
}

void requestCompletedCallback(void *cls,
                              struct MHD_Connection *con,
                              void **con_cls,
                              enum MHD_RequestTerminationCode toe)
{
  PRACRO_DEBUG(httpd, "requestCompletedCallback %p\n", con);

  // If connection was interrupted prematurely delete the content data here.
  if(*con_cls) {
    struct condata *cd = (struct condata*)*con_cls;
    delete cd;
    *con_cls = NULL;
  }
}

static void httpderr(void *arg, const char *fmt, va_list ap)
{
  PRACRO_ERR_VA(server, fmt, ap);
}

extern bool pracro_is_running;
void server()
{
  srand(time(NULL));

  bool forceshutdown = false;
  port_t port = Conf::server_port;

  int flags = MHD_USE_DEBUG | MHD_USE_SELECT_INTERNALLY;
  // | MHD_USE_PEDANTIC_CHECKS
#ifndef WITHOUT_SSL
  if(Conf::use_ssl) flags |= MHD_USE_SSL;
#endif

  PRACRO_DEBUG(server, "Server running on port %d.\n", port);

  Environment env;

  struct MHD_Daemon *d;
  d = MHD_start_daemon(flags, port, NULL, NULL,
                       handle_request_callback, &env,
                       MHD_OPTION_NOTIFY_COMPLETED,
                          requestCompletedCallback, NULL,
                       MHD_OPTION_CONNECTION_LIMIT, Conf::connection_limit,
#ifndef WITHOUT_SSL
                       MHD_OPTION_HTTPS_MEM_KEY, Conf::ssl_key.c_str(),
                       MHD_OPTION_HTTPS_MEM_CERT, Conf::ssl_cert.c_str(),
#endif
                       MHD_OPTION_CONNECTION_TIMEOUT, Conf::connection_timeout,
                       MHD_OPTION_EXTERNAL_LOGGER, httpderr, NULL,
                       MHD_OPTION_END);

  if(!d) {
    PRACRO_ERR(server, "Failed to initialise MHD_start_daemon!\n");
    return;
  }
 again:
  while(pracro_is_running) sleep(1);

  if(!forceshutdown && env.sessions.size() != 0) {
    char *errbuf;
    if(asprintf(&errbuf, "There are %d live sessions."
                " Kill again to force shutdown.\n",
                env.sessions.size()) != -1) {
      PRACRO_ERR_LOG(server, "%s", errbuf);
      log(errbuf);
      free(errbuf);
    }
    pracro_is_running = true;
    forceshutdown = true;
    goto again;
  }

  MHD_stop_daemon(d);

  PRACRO_DEBUG(server, "Server gracefully shut down.\n");
}


#ifdef TEST_SERVER

#include <sys/types.h>
#include <signal.h>

bool pracro_is_running = true;

char request[] = 
  "<?xml version='1.0' encoding='UTF-8'?>\n"
  "<pracro cpr=\"2003791613\" version=\"1.0\">\n"
  "  <request macro=\"example\" template=\"example\"/>\n"
  "</pracro>\n";

int main()
{
  Conf::xml_basedir = "../xml/";
  // Make sure wo don't interrupt an already running server.
  Conf::server_port = 32100;
  Conf::database_backend = "testdb";
  pid_t pid = fork();

  switch(pid) {
  case -1: // error
    perror("fork() failed!\n");
    return 1;
    
  case 0: // child
    try {
      server();
    } catch(Exception &e) {
      printf(e.what());
      return 1;
    }
    return 0;
    
  default: // parent
    try {
      //      sleep(1); // Make sure the server is started.
      TCPSocket socket;
      socket.connect("localhost", Conf::server_port);
      
      socket.write(request);

      //      sleep(1); // Make sure the server has handled the request.
      char buf[32];
      memset(buf, 0, sizeof(buf));
      //      while(socket.read(buf, 31, 1000)) {
      while(socket.read(buf, 31, 1000000)) {
        printf(buf); fflush(stdout);
        memset(buf, 0, sizeof(buf));
      }
    } catch(Exception &e) {
      printf(e.what());
      kill(pid, SIGKILL); // Kill the server again.
      return 1;
    }
    kill(pid, SIGKILL); // Kill the server again.
    return 0;
  }
  
  return 1;
}

#endif/*TEST_SERVER*/