/*
 *
 * (C) 2017-20 - ntop.org
 *
 * 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 3 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */

#include "ntop_includes.h"

/* ******************************************************** */

void FrequentStringItems::add(char *key, u_int32_t value) {
  std::map<std::string, u_int32_t>::iterator it;

  m.lock(__FILE__, __LINE__);

  it = q.find(std::string(key));

  if(it != q.end())
    it->second += value;
  else {
    if(q.size() > max_items_threshold)
      prune();

    q[std::string(key)] = value;
  }

  m.unlock(__FILE__, __LINE__);  
}

/* ******************************************************** */

static bool sortByVal(const pair<u_int32_t, std::string> &a,
		      const pair<u_int32_t, std::string> &b) {
  return (a.first < b.first);
} 

void FrequentStringItems::prune() {
  /* No lock here */
  u_int32_t num = 0; 
  std::vector< std::pair<u_int32_t, std::string> > vec;

  /*
    Sort the hash items by value and remove those who exceeded
    the threshold of max_items_threshold
  */
  for(std::map<std::string, u_int32_t>::iterator it1 = q.begin(); it1 != q.end(); ++it1)
    vec.push_back(std::make_pair(it1->second, it1->first));

  sort(vec.begin(), vec.end(), sortByVal);
  
  for(std::vector<std::pair<u_int32_t, std::string>>::iterator it2 = vec.begin(); it2 != vec.end(); ++it2) {
    if(++num < max_items) {
      /*
      u_int32_t id  = it2.first;
      std::string k = it2->second;
      q.erase(k);
      */
    } else
      break;
  }
}

/* ******************************************************** */

char* FrequentStringItems::json() {
  json_object *j;
  char *rsp;

  if((j = json_object_new_object()) == NULL) return(NULL);

  m.lock(__FILE__, __LINE__);

  for(std::map<std::string, u_int32_t>::iterator it = q.begin(); it != q.end(); ++it)
    json_object_object_add(j, it->first.c_str(), json_object_new_int64(it->second));

  rsp = strdup(json_object_to_json_string(j));
  json_object_put(j);
  m.unlock(__FILE__, __LINE__);
  
  return(rsp);
}

/* ******************************************* */

#ifdef TESTME

void testme() {
  FrequentStringItems *f = new FrequentStringItems(8);

  for(int i = 0; i<256; i++) {
    char buf[32];

    snprintf(buf, sizeof(buf), "%u", i % 24);
    f->add(buf, rand());
  }

  f->print();

  ntop->getTrace()->traceEvent(TRACE_NORMAL, "%s", f->json());
  
  exit(0);
}

#endif