/**
 * Copyright 2013-2020 Software Radio Systems Limited
 *
 * 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 SRSLTE_PDCP_ENTITY_LTE_H
#define SRSLTE_PDCP_ENTITY_LTE_H

#include "srslte/common/buffer_pool.h"
#include "srslte/common/common.h"
#include "srslte/common/log.h"
#include "srslte/common/security.h"
#include "srslte/common/threads.h"
#include "srslte/interfaces/ue_interfaces.h"
#include "srslte/upper/pdcp_entity_base.h"

namespace srslte {

/****************************************************************************
 * Structs and Defines
 * Ref: 3GPP TS 36.323 v10.1.0
 ***************************************************************************/

#define PDCP_CONTROL_MAC_I 0x00000000

/****************************************************************************
 * LTE PDCP Entity
 * Class for LTE PDCP entities
 ***************************************************************************/
class pdcp_entity_lte final : public pdcp_entity_base
{
public:
  pdcp_entity_lte(srsue::rlc_interface_pdcp* rlc_,
                  srsue::rrc_interface_pdcp* rrc_,
                  srsue::gw_interface_pdcp*  gw_,
                  srslte::task_sched_handle  task_sched_,
                  srslte::log_ref            log_,
                  uint32_t                   lcid_,
                  pdcp_config_t              cfg_);
  ~pdcp_entity_lte() override;
  void reset() override;
  void reestablish() override;

  // GW/RRC interface
  void write_sdu(unique_byte_buffer_t sdu) override;

  // RLC interface
  void write_pdu(unique_byte_buffer_t pdu) override;

  // Config helpers
  bool check_valid_config();

  void get_bearer_state(pdcp_lte_state_t* state) override;
  void set_bearer_state(const pdcp_lte_state_t& state) override;

private:
  srsue::rlc_interface_pdcp* rlc = nullptr;
  srsue::rrc_interface_pdcp* rrc = nullptr;
  srsue::gw_interface_pdcp*  gw  = nullptr;

  // State variables, as defined in TS 36 323, section 7.1
  pdcp_lte_state_t st = {};

  uint32_t reordering_window = 0;
  uint32_t maximum_pdcp_sn   = 0;

  void handle_srb_pdu(srslte::unique_byte_buffer_t pdu);
  void handle_um_drb_pdu(srslte::unique_byte_buffer_t pdu);
  void handle_am_drb_pdu(srslte::unique_byte_buffer_t pdu);
};

} // namespace srslte
#endif // SRSLTE_PDCP_ENTITY_LTE_H