/*
 *
 * (C) 2014-25 - 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.
 *
 */

#ifndef _FIFO_QUEUE_H
#define _FIFO_QUEUE_H

#include "ntop_includes.h"

template <typename T>
class FifoQueue {
 protected:
  Mutex m;
  std::queue<T> q;
  u_int32_t max_size;
  u_int64_t num_enqueued, num_not_enqueued, num_dequeued;

 public:
  FifoQueue(u_int32_t queue_size) {
    max_size = queue_size;
    num_enqueued = num_not_enqueued = num_dequeued = 0;
  }
  virtual ~FifoQueue() { ; }

  /*
    Subclasses might override this as sometimes the buffer
    needs to be duplicated as for strings
  */
  bool enqueue(T item) {
    bool rv;

    m.lock(__FILE__, __LINE__);

    if (canEnqueue()) {
      q.push(item);
      rv = true;
    } else
      rv = false;

    if (rv)
      num_enqueued++;
    else
      num_not_enqueued++;

    m.unlock(__FILE__, __LINE__);

    return (rv);
  }

  T dequeue() {
    T rv;

    m.lock(__FILE__, __LINE__);

    if (q.empty())
      rv = static_cast<T>(NULL);
    else {
      rv = q.front();
      q.pop();
      num_dequeued++;
    }
    m.unlock(__FILE__, __LINE__);

    return (rv);
  }

  inline bool canEnqueue() { return (getLength() < max_size); }
  inline u_int32_t getLength() { return (q.size()); }
  inline bool empty() { return (q.empty()); }
  inline float fillPct() {
    u_int64_t pending = num_enqueued - num_dequeued;
    if (pending == 0) return 0;
    return (float) pending / max_size * 100;
  };
  inline void lua(lua_State* vm, const char* table_name) {
    lua_newtable(vm);
    /* The percentage of not enqueued, with reference to the total number of not
     * enqueued plus enqueued */
    lua_push_uint64_table_entry(
        vm, "pct_not_enqueued",
        num_not_enqueued / (float)(num_not_enqueued + num_enqueued + 1) * 100);

    lua_pushstring(vm, table_name);
    lua_insert(vm, -2);
    lua_settable(vm, -3);
  }
};

#endif /* _FIFO_QUEUE_H */
