/**
 * Copyright 2013-2022 Software Radio Systems Limited
 *
 * This file is part of srsRAN.
 *
 * srsRAN 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.
 *
 * srsRAN 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/.
 *
 */

#include "srsgnb/hdr/stack/mac/mac_nr.h"
#include "srsgnb/hdr/stack/mac/sched_nr.h"
#include "srsran/common/buffer_pool.h"
#include "srsran/common/phy_cfg_nr_default.h"
#include "srsran/common/rwlock_guard.h"
#include "srsran/common/standard_streams.h"
#include "srsran/common/string_helpers.h"
#include "srsran/common/time_prof.h"
#include "srsran/mac/mac_rar_pdu_nr.h"

//#define WRITE_SIB_PCAP

namespace srsenb {

/**
 * @brief Handles UL PDU processing
 *
 * This class implements the demuxing of UL PDUs received at the MAC layer.
 * When the PHY decodes a valid PUSCH it passes the PDU to the MAC which
 * in turn puts them in a thread-safe task queue to return to the calling
 * thread as quick as possible.
 *
 * The demuxing of the PDUs for all users takes place on the Stack thread
 * which calls RLC and RRC for SDUs, or the MAC/scheduler for control elements.
 *
 */
class mac_nr_rx
{
public:
  explicit mac_nr_rx(rlc_interface_mac*          rlc_,
                     rrc_interface_mac_nr*       rrc_,
                     srsran::task_queue_handle&  stack_task_queue_,
                     sched_nr_interface*         sched_,
                     mac_interface_pdu_demux_nr& mac_,
                     srslog::basic_logger&       logger_) :
    task_queue(stack_task_queue_), rlc(rlc_), rrc(rrc_), sched(sched_), mac(mac_), logger(logger_)
  {}

  void handle_pdu(uint16_t rnti, srsran::unique_byte_buffer_t pdu)
  {
    task_queue.push(std::bind(
        [this, rnti](srsran::unique_byte_buffer_t& pdu) { handle_pdu_impl(rnti, std::move(pdu)); }, std::move(pdu)));
  }

private:
  int handle_pdu_impl(uint16_t rnti, srsran::unique_byte_buffer_t pdu)
  {
    pdu_ul.init_rx(true);
    if (pdu_ul.unpack(pdu->msg, pdu->N_bytes) != SRSRAN_SUCCESS) {
      return SRSRAN_ERROR;
    }

    if (logger.info.enabled()) {
      fmt::memory_buffer str_buffer;
      pdu_ul.to_string(str_buffer);
      logger.info("Rx PDU: rnti=0x%x, %s", rnti, srsran::to_c_str(str_buffer));
    }

    // Process MAC CRNTI CE first, if it exists
    uint32_t crnti_ce_pos = pdu_ul.get_num_subpdus();
    for (uint32_t n = pdu_ul.get_num_subpdus(); n > 0; --n) {
      srsran::mac_sch_subpdu_nr& subpdu = pdu_ul.get_subpdu(n - 1);
      if (subpdu.get_lcid() == srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::CRNTI) {
        if (process_ce_subpdu(rnti, subpdu) != SRSRAN_SUCCESS) {
          return SRSRAN_ERROR;
        }
        crnti_ce_pos = n - 1;
      }
    }

    // Process SDUs and remaining MAC CEs
    for (uint32_t n = 0; n < pdu_ul.get_num_subpdus(); ++n) {
      srsran::mac_sch_subpdu_nr& subpdu = pdu_ul.get_subpdu(n);
      if (subpdu.is_sdu()) {
        rrc->set_activity_user(rnti);
        rlc->write_pdu(rnti, subpdu.get_lcid(), subpdu.get_sdu(), subpdu.get_sdu_length());
      } else if (n != crnti_ce_pos) {
        if (process_ce_subpdu(rnti, subpdu) != SRSRAN_SUCCESS) {
          return SRSRAN_ERROR;
        }
      }
    }

    return SRSRAN_SUCCESS;
  }

  int process_ce_subpdu(uint16_t& rnti, const srsran::mac_sch_subpdu_nr& subpdu)
  {
    // Handle MAC CEs
    switch (subpdu.get_lcid()) {
      case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::CCCH_SIZE_48:
      case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::CCCH_SIZE_64: {
        srsran::mac_sch_subpdu_nr& ccch_subpdu = const_cast<srsran::mac_sch_subpdu_nr&>(subpdu);
        rlc->write_pdu(rnti, 0, ccch_subpdu.get_sdu(), ccch_subpdu.get_sdu_length());
        // store content for ConRes CE and schedule CE accordingly
        mac.store_msg3(rnti,
                       srsran::make_byte_buffer(ccch_subpdu.get_sdu(), ccch_subpdu.get_sdu_length(), __FUNCTION__));
        sched->dl_mac_ce(rnti, srsran::mac_sch_subpdu_nr::CON_RES_ID);
      } break;
      case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::CRNTI: {
        uint16_t ce_crnti  = subpdu.get_c_rnti();
        if (ce_crnti == SRSRAN_INVALID_RNTI) {
          logger.error("Malformed C-RNTI CE detected. C-RNTI can't be 0x0.", subpdu.get_lcid());
          return SRSRAN_ERROR;
        }
        uint16_t prev_rnti = rnti;
        rnti               = ce_crnti;
        rrc->update_user(prev_rnti, rnti);
        sched->ul_sr_info(rnti); // provide UL grant regardless of other BSR content for UE to complete RA
      } break;
      case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::SHORT_BSR:
      case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::SHORT_TRUNC_BSR: {
        srsran::mac_sch_subpdu_nr::lcg_bsr_t sbsr = subpdu.get_sbsr();
        uint32_t buffer_size_bytes                = buff_size_field_to_bytes(sbsr.buffer_size, srsran::SHORT_BSR);
        // Assume all LCGs are 0 if reported SBSR is 0
        if (buffer_size_bytes == 0) {
          for (uint32_t j = 0; j <= SCHED_NR_MAX_LC_GROUP; j++) {
            sched->ul_bsr(rnti, j, 0);
          }
        } else {
          sched->ul_bsr(rnti, sbsr.lcg_id, buffer_size_bytes);
        }
      } break;
      case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::LONG_BSR:
      case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::LONG_TRUNC_BSR: {
        srsran::mac_sch_subpdu_nr::lbsr_t lbsr = subpdu.get_lbsr();
        for (auto& lb : lbsr.list) {
          sched->ul_bsr(rnti, lb.lcg_id, buff_size_field_to_bytes(lb.buffer_size, srsran::LONG_BSR));
        }
      } break;
      case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::SE_PHR:
        // SE_PHR not implemented
        break;
      case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::PADDING:
        break;
      default:
        logger.warning("Unhandled subPDU with LCID=%d", subpdu.get_lcid());
    }

    return SRSRAN_SUCCESS;
  }

  /** Converts the buffer size field of a BSR (5 or 8-bit Buffer Size field) into Bytes
   * @param buff_size_field The buffer size field contained in the MAC PDU
   * @param format          The BSR format that determines the buffer size field length
   * @return uint32_t       The actual buffer size level in Bytes
   */
  static uint32_t buff_size_field_to_bytes(uint32_t buff_size_index, const srsran::bsr_format_nr_t& format)
  {
    using namespace srsran;

    // early exit
    if (buff_size_index == 0) {
      return 0;
    }

    const uint32_t max_offset = 1; // make the reported value bigger than the 2nd biggest

    switch (format) {
      case SHORT_BSR:
      case SHORT_TRUNC_BSR:
        if (buff_size_index >= buffer_size_levels_5bit_max_idx) {
          return buffer_size_levels_5bit[buffer_size_levels_5bit_max_idx] + max_offset;
        } else {
          return buffer_size_levels_5bit[buff_size_index];
        }
        break;
      case LONG_BSR:
      case LONG_TRUNC_BSR:
        if (buff_size_index > buffer_size_levels_8bit_max_idx) {
          return buffer_size_levels_8bit[buffer_size_levels_8bit_max_idx] + max_offset;
        } else {
          return buffer_size_levels_8bit[buff_size_index];
        }
        break;
      default:
        break;
    }
    return 0;
  }

  rlc_interface_mac*          rlc;
  rrc_interface_mac_nr*       rrc;
  sched_nr_interface*         sched;
  mac_interface_pdu_demux_nr& mac;
  srslog::basic_logger&       logger;
  srsran::task_queue_handle&  task_queue;

  srsran::mac_sch_pdu_nr pdu_ul;
};

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

mac_nr::mac_nr(srsran::task_sched_handle task_sched_) :
  logger(srslog::fetch_basic_logger("MAC-NR")),
  task_sched(task_sched_),
  bcch_bch_payload(srsran::make_byte_buffer()),
  rar_pdu_buffer(srsran::make_byte_buffer()),
  sched(new sched_nr{})
{
  stack_task_queue = task_sched.make_task_queue();
}

mac_nr::~mac_nr()
{
  stop();
}

int mac_nr::init(const mac_nr_args_t&    args_,
                 phy_interface_stack_nr* phy_,
                 stack_interface_mac*    stack_,
                 rlc_interface_mac*      rlc_,
                 rrc_interface_mac_nr*   rrc_)
{
  args = args_;

  phy   = phy_;
  stack = stack_;
  rlc   = rlc_;
  rrc   = rrc_;

  if (args.pcap.enable) {
    pcap = std::unique_ptr<srsran::mac_pcap>(new srsran::mac_pcap());
    pcap->open(args.pcap.filename);
  }

  logger.info("Started");

  started = true;

  return SRSRAN_SUCCESS;
}

void mac_nr::stop()
{
  bool started_prev = started.exchange(false);
  if (started_prev) {
    sched->stop();
    if (pcap != nullptr) {
      pcap->close();
    }
  }
}

/// Called from metrics thread.
/// Note: This can contend for the same mutexes as the ones used by L1/L2 workers.
///       However, get_metrics is called infrequently enough to cause major halts in the L1/L2
void mac_nr::get_metrics(srsenb::mac_metrics_t& metrics)
{
  // TODO: We should comment on the logic we follow to get the metrics. Some of them are retrieved from MAC, some
  // others from the scheduler.
  get_metrics_nolock(metrics);
  sched->get_metrics(metrics);
}

void mac_nr::get_metrics_nolock(srsenb::mac_metrics_t& metrics)
{
  srsran::rwlock_read_guard lock(rwmutex);
  metrics.ues.reserve(ue_db.size());
  for (auto& u : ue_db) {
    metrics.ues.emplace_back();
    u.second->metrics_read(&metrics.ues.back());
  }
  metrics.cc_info.resize(detected_rachs.size());
  for (unsigned cc = 0, e = detected_rachs.size(); cc != e; ++cc) {
    metrics.cc_info[cc].cc_rach_counter = detected_rachs[cc];
    metrics.cc_info[cc].pci             = (cc < cell_config.size()) ? cell_config[cc].pci : 0;
  }
}

int mac_nr::cell_cfg(const std::vector<srsenb::sched_nr_cell_cfg_t>& nr_cells)
{
  cell_config = nr_cells;
  sched->config(args.sched_cfg, nr_cells);
  detected_rachs.resize(nr_cells.size());

  // read SIBs from RRC (SIB1 for now only)
  for (uint32_t i = 0; i < nr_cells[0].sibs.size(); i++) {
    sib_info_t sib  = {};
    sib.index       = i;
    sib.periodicity = 160; // TODO: read period_rf from config
    sib.payload     = srsran::make_byte_buffer();
    if (sib.payload == nullptr) {
      logger.error("Couldn't allocate PDU in %s().", __FUNCTION__);
      return SRSRAN_ERROR;
    }
    if (rrc->read_pdu_bcch_dlsch(sib.index, *sib.payload) != SRSRAN_SUCCESS) {
      logger.error("Couldn't read SIB %d from RRC", sib.index);
    }

    logger.info("Including SIB %d into SI scheduling", sib.index + 1);
    bcch_dlsch_payload.push_back(std::move(sib));
  }

  rx.reset(new mac_nr_rx{rlc, rrc, stack_task_queue, sched.get(), *this, logger});

  default_ue_phy_cfg = get_common_ue_phy_cfg(cell_config[0]);

  return SRSRAN_SUCCESS;
}

int mac_nr::ue_cfg(uint16_t rnti, const sched_nr_interface::ue_cfg_t& ue_cfg)
{
  sched->ue_cfg(rnti, ue_cfg);
  return SRSRAN_SUCCESS;
}

uint16_t mac_nr::reserve_rnti(uint32_t enb_cc_idx, const sched_nr_ue_cfg_t& uecfg)
{
  uint16_t rnti = alloc_ue(enb_cc_idx);
  if (rnti == SRSRAN_INVALID_RNTI) {
    return rnti;
  }

  sched->ue_cfg(rnti, uecfg);

  return rnti;
}

void mac_nr::rach_detected(const rach_info_t& rach_info)
{
  static srsran::mutexed_tprof<srsran::avg_time_stats> rach_tprof("rach_tprof", "MAC-NR", 1);
  logger.set_context(rach_info.slot_index);
  auto rach_tprof_meas = rach_tprof.start();

  uint32_t enb_cc_idx = 0;
  stack_task_queue.push([this, rach_info, enb_cc_idx, rach_tprof_meas]() mutable {
    rach_tprof_meas.defer_stop();

    uint16_t rnti = alloc_ue(enb_cc_idx);

    // Log this event.
    {
      srsran::rwlock_write_guard lock(rwmutex);
      ++detected_rachs[enb_cc_idx];
    }

    // Trigger scheduler RACH
    srsenb::sched_nr_interface::rar_info_t rar_info = {};
    rar_info.cc                                     = enb_cc_idx;
    rar_info.preamble_idx                           = rach_info.preamble;
    rar_info.temp_crnti                             = rnti;
    rar_info.ta_cmd                                 = rach_info.time_adv;
    rar_info.prach_slot                             = slot_point{NUMEROLOGY_IDX, rach_info.slot_index};
    sched->dl_rach_info(rar_info);
    rrc->add_user(rnti, enb_cc_idx);

    logger.info("RACH:  slot=%d, cc=%d, preamble=%d, offset=%d, temp_crnti=0x%x",
                rach_info.slot_index,
                enb_cc_idx,
                rach_info.preamble,
                rach_info.time_adv,
                rnti);
    srsran::console("RACH:  slot=%d, cc=%d, preamble=%d, offset=%d, temp_crnti=0x%x\n",
                    rach_info.slot_index,
                    enb_cc_idx,
                    rach_info.preamble,
                    rach_info.time_adv,
                    rnti);
  });
}

uint16_t mac_nr::alloc_ue(uint32_t enb_cc_idx)
{
  ue_nr*   inserted_ue = nullptr;
  uint16_t rnti        = SRSRAN_INVALID_RNTI;

  do {
    // Assign new RNTI
    rnti = FIRST_RNTI + (ue_counter.fetch_add(1, std::memory_order_relaxed) % 60000);

    // Pre-check if rnti is valid
    {
      srsran::rwlock_read_guard read_lock(rwmutex);
      if (not is_rnti_valid_nolock(rnti)) {
        continue;
      }
    }

    // Allocate and initialize UE object
    std::unique_ptr<ue_nr> ue_ptr(new ue_nr(rnti, enb_cc_idx, sched.get(), rrc, rlc, phy, logger));

    // Add UE to rnti map
    srsran::rwlock_write_guard rw_lock(rwmutex);
    if (not is_rnti_valid_nolock(rnti)) {
      continue;
    }
    auto ret = ue_db.insert(rnti, std::move(ue_ptr));
    if (ret.has_value()) {
      inserted_ue = ret.value()->second.get();
    } else {
      logger.info("Failed to allocate rnti=0x%x. Attempting a different rnti.", rnti);
    }
  } while (inserted_ue == nullptr);

  return rnti;
}

// Remove UE from the perspective of L2/L3
int mac_nr::remove_ue(uint16_t rnti)
{
  srsran::rwlock_write_guard lock(rwmutex);
  if (is_rnti_active_nolock(rnti)) {
    sched->ue_rem(rnti);
    ue_db.erase(rnti);
  } else {
    logger.error("User rnti=0x%x not found", rnti);
    return SRSRAN_ERROR;
  }

  return SRSRAN_SUCCESS;
}

bool mac_nr::is_rnti_valid_nolock(uint16_t rnti)
{
  if (not started) {
    logger.info("RACH ignored as eNB is being shutdown");
    return false;
  }
  if (ue_db.full()) {
    logger.warning("Maximum number of connected UEs %zd connected to the eNB. Ignoring PRACH", SRSENB_MAX_UES);
    return false;
  }
  if (not ue_db.has_space(rnti)) {
    logger.info("Failed to allocate rnti=0x%x. Attempting a different rnti.", rnti);
    return false;
  }
  return true;
}

bool mac_nr::is_rnti_active_nolock(uint16_t rnti)
{
  if (not ue_db.contains(rnti)) {
    logger.error("User rnti=0x%x not found", rnti);
    return false;
  }
  return ue_db[rnti]->is_active();
}

int mac_nr::rlc_buffer_state(uint16_t rnti, uint32_t lc_id, uint32_t tx_queue, uint32_t retx_queue)
{
  sched->dl_buffer_state(rnti, lc_id, tx_queue, retx_queue);
  return SRSRAN_SUCCESS;
}

void mac_nr::ul_bsr(uint16_t rnti, uint32_t lcid, uint32_t bsr)
{
  sched->ul_bsr(rnti, lcid, bsr);
}

int mac_nr::slot_indication(const srsran_slot_cfg_t& slot_cfg)
{
  return 0;
}

void mac_nr::store_msg3(uint16_t rnti, srsran::unique_byte_buffer_t pdu)
{
  srsran::rwlock_read_guard rw_lock(rwmutex);
  if (is_rnti_active_nolock(rnti)) {
    ue_db[rnti]->store_msg3(std::move(pdu));
  } else {
    logger.error("User rnti=0x%x not found. Can't store Msg3.", rnti);
  }
}

mac_nr::dl_sched_t* mac_nr::get_dl_sched(const srsran_slot_cfg_t& slot_cfg)
{
  slot_point pdsch_slot = srsran::slot_point{NUMEROLOGY_IDX, slot_cfg.idx};

  logger.set_context((pdsch_slot - TX_ENB_DELAY).to_uint());

  // Initiate new slot and sync UE internal states
  sched->slot_indication(pdsch_slot);

  // Run DL Scheduler for CC
  sched_nr::dl_res_t* dl_res = sched->get_dl_sched(pdsch_slot, 0);
  if (dl_res == nullptr) {
    return nullptr;
  }

  // Generate MAC DL PDUs
  uint32_t                  rar_count = 0, si_count = 0, data_count = 0;
  srsran::rwlock_read_guard rw_lock(rwmutex);
  for (pdsch_t& pdsch : dl_res->phy.pdsch) {
    if (pdsch.sch.grant.rnti_type == srsran_rnti_type_c) {
      uint16_t rnti = pdsch.sch.grant.rnti;
      if (not is_rnti_active_nolock(rnti)) {
        continue;
      }
      for (auto& tb_data : pdsch.data) {
        if (tb_data != nullptr and tb_data->N_bytes == 0) {
          // TODO: exclude retx from packing
          const sched_nr_interface::dl_pdu_t& pdu = dl_res->data[data_count++];
          ue_db[rnti]->generate_pdu(tb_data, pdsch.sch.grant.tb->tbs / 8, pdu.subpdus);

          if (pcap != nullptr) {
            uint32_t pid = 0; // TODO: get PID from PDCCH struct?
            pcap->write_dl_crnti_nr(tb_data->msg, tb_data->N_bytes, rnti, pid, slot_cfg.idx);
          }
          ue_db[rnti]->metrics_dl_mcs(pdsch.sch.grant.tb->mcs);
        }
      }
    } else if (pdsch.sch.grant.rnti_type == srsran_rnti_type_ra) {
      sched_nr_interface::rar_t& rar = dl_res->rar[rar_count++];
      // for RARs we could actually move the byte_buffer to the PHY, as there are no retx
      pdsch.data[0] = assemble_rar(rar.grants);
    } else if (pdsch.sch.grant.rnti_type == srsran_rnti_type_si) {
      uint32_t sib_idx = dl_res->sib_idxs[si_count++];
      pdsch.data[0]    = bcch_dlsch_payload[sib_idx].payload.get();
#ifdef WRITE_SIB_PCAP
      if (pcap != nullptr) {
        pcap->write_dl_si_rnti_nr(bcch_dlsch_payload[sib_idx].payload->msg,
                                  bcch_dlsch_payload[sib_idx].payload->N_bytes,
                                  SI_RNTI,
                                  0,
                                  slot_cfg.idx);
      }
#endif
    }
  }
  for (auto& u : ue_db) {
    u.second->metrics_cnt();
  }

  return &dl_res->phy;
}

mac_nr::ul_sched_t* mac_nr::get_ul_sched(const srsran_slot_cfg_t& slot_cfg)
{
  slot_point  pusch_slot = srsran::slot_point{NUMEROLOGY_IDX, slot_cfg.idx};
  ul_sched_t* ul_sched   = sched->get_ul_sched(pusch_slot, 0);

  srsran::rwlock_read_guard rw_lock(rwmutex);
  for (auto& pusch : ul_sched->pusch) {
    if (ue_db.contains(pusch.sch.grant.rnti)) {
      ue_db[pusch.sch.grant.rnti]->metrics_ul_mcs(pusch.sch.grant.tb->mcs);
    }
  }
  return ul_sched;
}

int mac_nr::pucch_info(const srsran_slot_cfg_t& slot_cfg, const mac_interface_phy_nr::pucch_info_t& pucch_info)
{
  if (not handle_uci_data(pucch_info.uci_data.cfg.pucch.rnti, pucch_info.uci_data.cfg, pucch_info.uci_data.value)) {
    logger.error("Error handling UCI data from PUCCH reception");
    return SRSRAN_ERROR;
  }

  // process PUCCH SNR
  uint16_t                  rnti = pucch_info.uci_data.cfg.pucch.rnti;
  srsran::rwlock_read_guard rw_lock(rwmutex);
  if (ue_db.contains(rnti)) {
    ue_db[rnti]->metrics_pucch_sinr(pucch_info.csi.snr_dB);
  }

  return SRSRAN_SUCCESS;
}

bool mac_nr::handle_uci_data(uint16_t rnti, const srsran_uci_cfg_nr_t& cfg_, const srsran_uci_value_nr_t& value)
{
  // Process HARQ-ACK
  for (uint32_t i = 0; i < cfg_.ack.count; i++) {
    const srsran_harq_ack_bit_t* ack_bit = &cfg_.ack.bits[i];
    bool                         is_ok   = (value.ack[i] == 1) and value.valid;
    sched->dl_ack_info(rnti, 0, ack_bit->pid, 0, is_ok);
    srsran::rwlock_read_guard rw_lock(rwmutex);
    if (ue_db.contains(rnti)) {
      ue_db[rnti]->metrics_tx(is_ok, 0 /*TODO get size of packet from scheduler somehow*/);
    }
  }

  // Process SR
  if (value.valid and value.sr > 0) {
    sched->ul_sr_info(cfg_.pucch.rnti);
  }

  // Process CQI
  for (uint32_t i = 0; i < cfg_.nof_csi; i++) {
    // Skip if invalid or not supported CSI report
    if (not value.valid or cfg_.csi[i].cfg.quantity != SRSRAN_CSI_REPORT_QUANTITY_CRI_RI_PMI_CQI or
        cfg_.csi[i].cfg.freq_cfg != SRSRAN_CSI_REPORT_FREQ_WIDEBAND or value.csi[i].wideband_cri_ri_pmi_cqi.cqi == 0) {
      continue;
    }

    // 1. Pass CQI report to scheduler
    sched->dl_cqi_info(rnti, 0, value.csi->wideband_cri_ri_pmi_cqi.cqi);

    // 2. Save CQI report for metrics stats
    srsran::rwlock_read_guard rw_lock(rwmutex);
    if (ue_db.contains(rnti) && value.valid) {
      ue_db[rnti]->metrics_dl_cqi(cfg_, value.csi->wideband_cri_ri_pmi_cqi.cqi);
    }
  }

  return true;
}

int mac_nr::pusch_info(const srsran_slot_cfg_t& slot_cfg, mac_interface_phy_nr::pusch_info_t& pusch_info)
{
  uint16_t rnti      = pusch_info.rnti;
  uint32_t nof_bytes = pusch_info.pdu->N_bytes;

  // Handle UCI data
  if (not handle_uci_data(rnti, pusch_info.uci_cfg, pusch_info.pusch_data.uci)) {
    logger.error("Error handling UCI data from PUCCH reception");
    return SRSRAN_ERROR;
  }

  sched->ul_crc_info(rnti, 0, pusch_info.pid, pusch_info.pusch_data.tb[0].crc);

  // process only PDUs with CRC=OK
  if (pusch_info.pusch_data.tb[0].crc) {
    if (pcap) {
      pcap->write_ul_crnti_nr(
          pusch_info.pdu->msg, pusch_info.pdu->N_bytes, pusch_info.rnti, pusch_info.pid, slot_cfg.idx);
    }

    // Decode and send PDU to upper layers
    rx->handle_pdu(rnti, std::move(pusch_info.pdu));
  }
  srsran::rwlock_read_guard rw_lock(rwmutex);
  if (ue_db.contains(rnti)) {
    ue_db[rnti]->metrics_rx(pusch_info.pusch_data.tb[0].crc, nof_bytes);
    ue_db[rnti]->metrics_pusch_sinr(pusch_info.csi.snr_dB);
  }
  return SRSRAN_SUCCESS;
}

srsran::byte_buffer_t* mac_nr::assemble_rar(srsran::const_span<sched_nr_interface::msg3_grant_t> grants)
{
  srsran::mac_rar_pdu_nr rar_pdu;

  uint32_t pdsch_tbs = 10; // TODO: how big is the PDSCH?
  rar_pdu.init_tx(rar_pdu_buffer.get(), pdsch_tbs);

  for (auto& rar_grant : grants) {
    srsran::mac_rar_subpdu_nr& rar_subpdu = rar_pdu.add_subpdu();

    // set values directly coming from scheduler
    rar_subpdu.set_ta(rar_grant.data.ta_cmd);
    rar_subpdu.set_rapid(rar_grant.data.preamble_idx);
    rar_subpdu.set_temp_crnti(rar_grant.data.temp_crnti);

    // convert Msg3 grant to raw UL grant
    srsran_dci_nr_t     dci     = {};
    srsran_dci_msg_nr_t dci_msg = {};
    if (srsran_dci_nr_ul_pack(&dci, &rar_grant.msg3_dci, &dci_msg) != SRSRAN_SUCCESS) {
      logger.error("Couldn't pack Msg3 UL grant");
      return nullptr;
    }

    if (logger.info.enabled()) {
      std::array<char, 512> str;
      srsran_dci_ul_nr_to_str(&dci, &rar_grant.msg3_dci, str.data(), str.size());
      logger.info("Setting RAR Grant %s", str.data());
    }

    // copy only the required bits
    std::array<uint8_t, SRSRAN_RAR_UL_GRANT_NBITS> packed_ul_grant = {};
    std::copy(
        std::begin(dci_msg.payload), std::begin(dci_msg.payload) + SRSRAN_RAR_UL_GRANT_NBITS, packed_ul_grant.begin());
    rar_subpdu.set_ul_grant(packed_ul_grant);
  }

  if (rar_pdu.pack() != SRSRAN_SUCCESS) {
    logger.error("Couldn't assemble RAR PDU");
    return nullptr;
  }

  fmt::memory_buffer buff;
  rar_pdu.to_string(buff);
  logger.info("%s", srsran::to_c_str(buff));

  return rar_pdu_buffer.get();
}

} // namespace srsenb