/**
 *
 * \section COPYRIGHT
 *
 * Copyright 2013-2017 Software Radio Systems Limited
 *
 * \section LICENSE
 *
 * This file is part of srsLTE.
 *
 * srsLTE is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * srsLTE 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 Affero General Public License for more details.
 *
 * A copy of the GNU Affero General Public License can be found in
 * the LICENSE file in the top-level directory of this distribution
 * and at http://www.gnu.org/licenses/.
 *
 */
#ifndef SRSEPC_S1AP_H
#define SRSEPC_S1AP_H

#include "srslte/asn1/gtpc.h"
#include "srslte/asn1/liblte_s1ap.h"
#include "srslte/asn1/liblte_mme.h"
#include "srslte/common/common.h"
#include "srslte/common/log.h"
#include "srslte/common/s1ap_pcap.h"
#include "srslte/interfaces/epc_interfaces.h"

#include <strings.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/sctp.h>
#include <unistd.h>
#include <map>
#include <set>
#include "nas.h"
#include "s1ap_mngmt_proc.h"
#include "s1ap_nas_transport.h"
#include "s1ap_ctx_mngmt_proc.h"
#include "mme_gtpc.h"
#include "srsepc/hdr/hss/hss.h"

namespace srsepc{

const uint16_t S1MME_PORT = 36412;

class s1ap:
    public s1ap_interface_nas,
    public s1ap_interface_gtpc
{
public:

  static s1ap* get_instance();
  static void cleanup();

  int enb_listen();
  int init(s1ap_args_t s1ap_args, srslte::log_filter *s1ap_log, srslte::log_filter *nas_log, hss_interface_nas * hss_);
  void stop();

  int get_s1_mme();

  void delete_enb_ctx(int32_t assoc_id);

  bool s1ap_tx_pdu(srslte::byte_buffer_t *pdu, struct sctp_sndrcvinfo *enb_sri);
  bool handle_s1ap_rx_pdu(srslte::byte_buffer_t *pdu, struct sctp_sndrcvinfo *enb_sri);
  bool handle_initiating_message(LIBLTE_S1AP_INITIATINGMESSAGE_STRUCT *msg, struct sctp_sndrcvinfo *enb_sri);
  bool handle_successful_outcome(LIBLTE_S1AP_SUCCESSFULOUTCOME_STRUCT *msg);

  void activate_eps_bearer(uint64_t imsi, uint8_t ebi);

  void print_enb_ctx_info(const std::string &prefix, const enb_ctx_t &enb_ctx);

  uint32_t get_plmn();
  uint32_t get_next_mme_ue_s1ap_id();
  enb_ctx_t* find_enb_ctx(uint16_t enb_id);
  void add_new_enb_ctx(const enb_ctx_t &enb_ctx, const struct sctp_sndrcvinfo* enb_sri);
  void get_enb_ctx(uint16_t sctp_stream);

  bool add_nas_ctx_to_imsi_map(nas *nas_ctx);
  bool add_nas_ctx_to_mme_ue_s1ap_id_map(nas *nas_ctx);
  bool add_ue_to_enb_set(int32_t enb_assoc, uint32_t mme_ue_s1ap_id);

  virtual nas* find_nas_ctx_from_imsi(uint64_t imsi);
  nas* find_nas_ctx_from_mme_ue_s1ap_id(uint32_t mme_ue_s1ap_id);

  bool release_ue_ecm_ctx(uint32_t mme_ue_s1ap_id);
  void release_ues_ecm_ctx_in_enb(int32_t enb_assoc);
  bool delete_ue_ctx(uint64_t imsi);

  uint32_t allocate_m_tmsi(uint64_t imsi);
  virtual uint64_t find_imsi_from_m_tmsi(uint32_t m_tmsi);

  s1ap_args_t                    m_s1ap_args;
  srslte::log_filter            *m_s1ap_log;
  srslte::log_filter            *m_nas_log;

  s1ap_mngmt_proc*               m_s1ap_mngmt_proc;
  s1ap_nas_transport*            m_s1ap_nas_transport;
  s1ap_ctx_mngmt_proc*           m_s1ap_ctx_mngmt_proc;

  std::map<uint32_t, uint64_t>   m_tmsi_to_imsi;

  //Interfaces
  virtual bool send_initial_context_setup_request(uint64_t imsi, uint16_t erab_to_setup);
  virtual bool send_ue_context_release_command(uint32_t mme_ue_s1ap_id);
  virtual bool send_downlink_nas_transport(uint32_t enb_ue_s1ap_id, uint32_t mme_ue_s1ap_id, srslte::byte_buffer_t *nas_msg, struct sctp_sndrcvinfo enb_sri);
private:
  s1ap();
  virtual ~s1ap();

  static s1ap *m_instance;

  uint32_t                       m_plmn;
  srslte::byte_buffer_pool      *m_pool;

  hss_interface_nas *m_hss;
  int m_s1mme;
  std::map<uint16_t, enb_ctx_t*>                    m_active_enbs;
  std::map<int32_t, uint16_t>                       m_sctp_to_enb_id;
  std::map<int32_t,std::set<uint32_t> >             m_enb_assoc_to_ue_ids;

  std::map<uint64_t, nas*>                          m_imsi_to_nas_ctx;
  std::map<uint32_t, nas*>                          m_mme_ue_s1ap_id_to_nas_ctx;

  uint32_t                                          m_next_mme_ue_s1ap_id;
  uint32_t                                          m_next_m_tmsi;

  //FIXME the GTP-C should be moved to the MME class, when the packaging of GTP-C messages is done.
  mme_gtpc *m_mme_gtpc;

  //PCAP
  bool              m_pcap_enable;
  srslte::s1ap_pcap m_pcap;
};

inline uint32_t
s1ap::get_plmn()
{
  return m_plmn;
}


} //namespace srsepc

#endif // SRSEPC_S1AP_H