/*
 * 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_SCHED_LCH_H
#define SRSLTE_SCHED_LCH_H

#include "srslte/common/logmap.h"
#include "srslte/interfaces/sched_interface.h"
#include "srslte/mac/pdu.h"

namespace srsenb {

class lch_manager
{
  constexpr static uint32_t pbr_infinity = -1;
  constexpr static uint32_t MAX_LC       = sched_interface::MAX_LC;

public:
  void set_cfg(const sched_interface::ue_cfg_t& cfg_);
  void new_tti();

  void config_lcid(uint32_t lcg_id, const sched_interface::ue_bearer_cfg_t& bearer_cfg);
  void ul_bsr(uint8_t lcg_id, uint32_t bsr);
  void ul_buffer_add(uint8_t lcid, uint32_t bytes);
  void dl_buffer_state(uint8_t lcid, uint32_t tx_queue, uint32_t retx_queue);

  int alloc_rlc_pdu(sched_interface::dl_sched_pdu_t* lcid, int rem_bytes);

  bool is_bearer_active(uint32_t lcid) const;
  bool is_bearer_ul(uint32_t lcid) const;
  bool is_bearer_dl(uint32_t lcid) const;

  int get_dl_tx_total() const;
  int get_dl_tx_total(uint32_t lcid) const { return get_dl_tx(lcid) + get_dl_retx(lcid); }
  int get_dl_tx(uint32_t lcid) const;
  int get_dl_retx(uint32_t lcid) const;
  int get_bsr(uint32_t lcid) const;
  int get_bsr_with_overhead(uint32_t lcid) const;
  int get_max_prio_lcid() const;

  std::string get_bsr_text() const;

  // Control Element Command queue
  using ce_cmd = srslte::dl_sch_lcid;
  std::deque<ce_cmd> pending_ces;

private:
  struct ue_bearer_t {
    sched_interface::ue_bearer_cfg_t cfg         = {};
    int                              bucket_size = 0;
    int                              buf_tx      = 0;
    int                              buf_retx    = 0;
    int                              Bj          = 0;
  };

  int alloc_retx_bytes(uint8_t lcid, int rem_bytes);
  int alloc_tx_bytes(uint8_t lcid, int rem_bytes);

  size_t                                           prio_idx = 0;
  srslte::log_ref                                  log_h{"MAC"};
  std::array<ue_bearer_t, sched_interface::MAX_LC> lch     = {};
  std::array<int, 4>                               lcg_bsr = {};
};

/**
 * Allocate space for multiple MAC SDUs (i.e. RLC PDUs) and corresponding MAC SDU subheaders
 * @param data struct where the rlc pdu allocations are stored
 * @param total_tbs available TB size for allocations for a single UE
 * @param tbidx index of TB
 * @return allocated bytes, which is always equal or lower than total_tbs
 */
uint32_t
allocate_mac_sdus(sched_interface::dl_sched_data_t* data, lch_manager& lch_handler, uint32_t total_tbs, uint32_t tbidx);

/**
 * Allocate space for pending MAC CEs
 * @param data struct where the MAC CEs allocations are stored
 * @param total_tbs available space in bytes for allocations
 * @return number of bytes allocated
 */
uint32_t allocate_mac_ces(sched_interface::dl_sched_data_t* data,
                          lch_manager&                      lch_handler,
                          uint32_t                          total_tbs,
                          uint32_t                          ue_cc_idx);

} // namespace srsenb

#endif // SRSLTE_SCHED_LCH_H