/*
 * Copyright 2013-2019 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/.
 *
 */

#include "srsenb/hdr/phy/txrx.h"
#include "srslte/asn1/rrc_asn1.h"
#include "srslte/common/log.h"
#include "srslte/common/threads.h"
#include "srslte/phy/channel/channel.h"
#include <sstream>

#include <assert.h>

#define Error(fmt, ...)                                                                                                \
  if (SRSLTE_DEBUG_ENABLED)                                                                                            \
  log_h->error(fmt, ##__VA_ARGS__)
#define Warning(fmt, ...)                                                                                              \
  if (SRSLTE_DEBUG_ENABLED)                                                                                            \
  log_h->warning(fmt, ##__VA_ARGS__)
#define Info(fmt, ...)                                                                                                 \
  if (SRSLTE_DEBUG_ENABLED)                                                                                            \
  log_h->info(fmt, ##__VA_ARGS__)
#define Debug(fmt, ...)                                                                                                \
  if (SRSLTE_DEBUG_ENABLED)                                                                                            \
  log_h->debug(fmt, ##__VA_ARGS__)

using namespace std;
using namespace asn1::rrc;

namespace srsenb {

phy_common::phy_common(uint32_t max_workers_) : tx_sem(max_workers_), cell_list()
{
  params.max_prach_offset_us = 20;
  max_workers                = max_workers_;

  for (uint32_t i = 0; i < max_workers; i++) {
    sem_init(&tx_sem[i], 0, 0); // All semaphores start blocked
  }
}

phy_common::~phy_common()
{
  for (uint32_t i = 0; i < max_workers; i++) {
    sem_destroy(&tx_sem[i]);
  }
}

void phy_common::set_nof_workers(uint32_t nof_workers_)
{
  nof_workers = nof_workers_;
}

void phy_common::reset()
{
  for (auto& q : dl_grants) {
    for (auto& g : q) {
      g = {};
    }
  }
  for (auto& q : ul_grants) {
    for (auto& g : q) {
      g = {};
    }
  }
}

bool phy_common::init(const phy_cell_cfg_list_t&   cell_list_,
                      srslte::radio_interface_phy* radio_h_,
                      stack_interface_phy_lte*     stack_)
{
  radio     = radio_h_;
  stack     = stack_;
  cell_list = cell_list_;

  pthread_mutex_init(&mtch_mutex, nullptr);
  pthread_cond_init(&mtch_cvar, nullptr);

  // Instantiate DL channel emulator
  if (params.ul_channel_args.enable) {
    dl_channel = srslte::channel_ptr(new srslte::channel(params.dl_channel_args, 1));
    dl_channel->set_srate((uint32_t)srslte_sampling_freq_hz(cell_list[0].cell.nof_prb));
  }

  // Create grants
  for (auto& q : dl_grants) {
    q.resize(cell_list.size());
  }
  for (auto& q : ul_grants) {
    q.resize(cell_list.size());
  }

  is_first_tx = true;

  reset();
  return true;
}

void phy_common::stop()
{
  for (uint32_t i = 0; i < max_workers; i++) {
    sem_post(&tx_sem[i]);
  }
}

/* The transmission of UL subframes must be in sequence. The correct sequence is guaranteed by a chain of N semaphores,
 * one per TTI%nof_workers. Each threads waits for the semaphore for the current thread and after transmission allows
 * next TTI to be transmitted
 *
 * Each worker uses this function to indicate that all processing is done and data is ready for transmission or
 * there is no transmission at all (tx_enable). In that case, the end of burst message will be sent to the radio
 */
void phy_common::worker_end(uint32_t           tti,
                            cf_t*              buffer[SRSLTE_MAX_PORTS],
                            uint32_t           nof_samples,
                            srslte_timestamp_t tx_time)
{

  // This variable is not protected but it is very unlikely that 2 threads arrive here simultaneously since at the
  // beginning there is no workload and threads are separated by 1 ms
  if (is_first_tx) {
    is_first_tx = false;
    // Allow my own transmission if I'm the first to transmit
    sem_post(&tx_sem[tti % nof_workers]);
  }

  // Wait for the green light to transmit in the current TTI
  sem_wait(&tx_sem[tti % nof_workers]);

  if (dl_channel) {
    dl_channel->run(buffer, buffer, nof_samples, tx_time);
  }

  // always transmit on single radio
  radio->tx(0, buffer, nof_samples, tx_time);

  // Allow next TTI to transmit
  sem_post(&tx_sem[(tti + 1) % nof_workers]);

  // Trigger MAC clock
  stack->tti_clock();
}

void phy_common::ue_db_clear_tti_pending_ack(uint32_t tti)
{
  std::lock_guard<std::mutex> lock(user_mutex);

  for (auto& iter : common_ue_db) {
    common_ue& ue = iter.second;

    // Reset all pending ACKs in all carriers
    ue.pending_ack[TTIMOD(tti)] = {};
  }
}

void phy_common::ue_db_addmod_rnti(uint16_t rnti, const std::vector<uint32_t>& cell_index_list)
{
  std::lock_guard<std::mutex> lock(user_mutex);

  // Create new user if did not exist
  if (!common_ue_db.count(rnti)) {
    add_rnti(rnti);
  }

  // Get UE by reference
  common_ue& ue = common_ue_db[rnti];

  // Clear SCell map to avoid overlap from previous calls
  ue.scell_map.clear();

  // Add SCells to map
  for (uint32_t i = 0; i < cell_index_list.size(); i++) {
    common_ue_db[rnti].scell_map[cell_index_list[i]] = i;
  }
}

// Private function not mutexed
void phy_common::add_rnti(uint16_t rnti)
{
  for (auto& pending_ack : common_ue_db[rnti].pending_ack) {
    pending_ack = {};
  }
}

void phy_common::ue_db_rem_rnti(uint16_t rnti)
{
  std::lock_guard<std::mutex> lock(user_mutex);
  if (!common_ue_db.count(rnti)) {
    common_ue_db.erase(rnti);
  }
}

void phy_common::ue_db_set_ack_pending(uint32_t tti, uint32_t cc_idx, const srslte_dci_dl_t& dci)
{
  std::lock_guard<std::mutex> lock(user_mutex);

  // Check if the UE exists
  if (!common_ue_db.count(dci.rnti)) {
    return;
  }

  // Check Component Carrier is part of UE SCell map
  common_ue& ue = common_ue_db[dci.rnti];
  if (!ue.scell_map.count(cc_idx)) {
    return;
  }

  uint32_t       scell_idx   = ue.scell_map[cc_idx];
  uint32_t       tti_idx     = TTIMOD(tti);
  pending_ack_t& pending_ack = ue.pending_ack[tti_idx]; // Assume it has been zero'ed for the TTI

  // Set DCI info
  pending_ack.ack[scell_idx].grant_cc_idx = scell_idx; // No cross carrier scheduling supported
  pending_ack.ack[scell_idx].ncce[0]      = dci.location.ncce;

  // Set TB info
  for (uint32_t i = 0; i < srslte_dci_format_max_tb(dci.format); i++) {
    if (SRSLTE_DCI_IS_TB_EN(dci.tb[i])) {
      pending_ack.ack[scell_idx].pending_tb[i] = true;
      pending_ack.ack[scell_idx].nof_acks++;
    }
  }
}

void phy_common::ue_db_get_ack_pending(uint32_t             tti,
                                       uint32_t             cc_idx,
                                       uint16_t             rnti,
                                       srslte_uci_cfg_ack_t uci_cfg_ack[SRSLTE_MAX_CARRIERS])
{
  std::lock_guard<std::mutex> lock(user_mutex);

  // Check if the UE exists
  if (!common_ue_db.count(rnti)) {
    return;
  }

  common_ue& ue      = common_ue_db[rnti];
  uint32_t   tti_idx = TTIMOD(tti);

  // Check Component Carrier is the UE PCell
  if (common_ue_db[rnti].pcell_idx == cc_idx) {
    srslte_uci_cfg_ack_t* pending_acks = ue.pending_ack[tti_idx].ack;

    for (uint32_t i = 0; i < SRSLTE_MAX_CARRIERS; i++) {
      // Copy pending acks
      uci_cfg_ack[i] = pending_acks[i];

      // Reset stored pending acks
      pending_acks[i] = {};
    }
  } else {
    for (uint32_t i = 0; i < SRSLTE_MAX_CARRIERS; i++) {
      // Set all to zeros, equivalent to no UCI data
      uci_cfg_ack[i] = {};
    }
  }
}

uint32_t phy_common::ue_db_get_nof_ca_cells(uint16_t rnti)
{
  std::lock_guard<std::mutex> lock(user_mutex);
  auto                        ret = 0;
  if (common_ue_db.count(rnti)) {
    ret = common_ue_db[rnti].scell_map.size();
  }
  return ret;
}

uint32_t phy_common::ue_db_get_cc_pcell(uint16_t rnti)
{
  std::lock_guard<std::mutex> lock(user_mutex);
  auto                        ret = static_cast<uint32_t>(cell_list.size());
  if (common_ue_db.count(rnti)) {
    ret = common_ue_db[rnti].pcell_idx;
  }
  return ret;
}

uint32_t phy_common::ue_db_get_cc_scell(uint16_t rnti, uint32_t scell_idx)
{
  std::lock_guard<std::mutex> lock(user_mutex);

  if (common_ue_db.count(rnti)) {
    auto& ue = common_ue_db[rnti];
    for (auto& it : ue.scell_map) {
      if (it.second == scell_idx) {
        return it.first;
      }
    }
  }

  return static_cast<uint32_t>(cell_list.size());
}

void phy_common::ue_db_set_ri(uint16_t rnti, uint8_t ri)
{
  std::lock_guard<std::mutex> lock(user_mutex);
  if (common_ue_db.count(rnti)) {
    common_ue_db[rnti].ri = ri;
  }
}

uint8_t phy_common::ue_db_get_ri(uint16_t rnti)
{
  std::lock_guard<std::mutex> lock(user_mutex);
  uint8_t                     ret = 0;
  if (common_ue_db.count(rnti)) {
    ret = common_ue_db[rnti].ri;
  }
  return ret;
}

void phy_common::ue_db_set_last_ul_tb(uint16_t rnti, uint32_t pid, srslte_ra_tb_t tb)
{
  std::lock_guard<std::mutex> lock(user_mutex);
  if (!common_ue_db.count(rnti)) {
    add_rnti(rnti);
  }
  common_ue_db[rnti].last_tb[pid % SRSLTE_MAX_HARQ_PROC] = tb;
}

srslte_ra_tb_t phy_common::ue_db_get_last_ul_tb(uint16_t rnti, uint32_t pid)
{
  std::lock_guard<std::mutex> lock(user_mutex);
  srslte_ra_tb_t              ret = {};
  if (common_ue_db.count(rnti)) {
    ret = common_ue_db[rnti].last_tb[pid % SRSLTE_FDD_NOF_HARQ];
  }
  return ret;
}

void phy_common::set_mch_period_stop(uint32_t stop)
{
  pthread_mutex_lock(&mtch_mutex);
  have_mtch_stop  = true;
  mch_period_stop = stop;
  pthread_cond_signal(&mtch_cvar);
  pthread_mutex_unlock(&mtch_mutex);
}

void phy_common::configure_mbsfn(phy_interface_stack_lte::phy_cfg_mbsfn_t* cfg)
{
  mbsfn = *cfg;

  build_mch_table();
  build_mcch_table();
  sib13_configured = true;
  mcch_configured  = true;
}

void phy_common::build_mch_table()
{
  // First reset tables
  ZERO_OBJECT(mcch_table);

  // 40 element table represents 4 frames (40 subframes)
  uint32_t nof_sfs = 0;
  if (mbsfn.mbsfn_subfr_cnfg.sf_alloc.type().value == mbsfn_sf_cfg_s::sf_alloc_c_::types::one_frame) {
    generate_mch_table(&mch_table[0], (uint32_t)mbsfn.mbsfn_subfr_cnfg.sf_alloc.one_frame().to_number(), 1);
    nof_sfs = 10;
  } else if (mbsfn.mbsfn_subfr_cnfg.sf_alloc.type().value == mbsfn_sf_cfg_s::sf_alloc_c_::types::four_frames) {
    generate_mch_table(&mch_table[0], (uint32_t)mbsfn.mbsfn_subfr_cnfg.sf_alloc.four_frames().to_number(), 4);
    nof_sfs = 40;
  } else {
    fprintf(stderr, "No valid SF alloc\n");
  }
  // Debug
  std::stringstream ss;
  ss << "|";
  for (uint32_t j = 0; j < 40; j++) {
    ss << (int)mch_table[j] << "|";
  }

  stack->set_sched_dl_tti_mask(mch_table, nof_sfs);
}

void phy_common::build_mcch_table()
{
  ZERO_OBJECT(mcch_table);

  generate_mcch_table(mcch_table, static_cast<uint32>(mbsfn.mbsfn_area_info.mcch_cfg_r9.sf_alloc_info_r9.to_number()));

  std::stringstream ss;
  ss << "|";
  for (uint32_t j = 0; j < 10; j++) {
    ss << (int)mcch_table[j] << "|";
  }
}

bool phy_common::is_mcch_subframe(srslte_mbsfn_cfg_t* cfg, uint32_t phy_tti)
{
  uint32_t sfn; // System Frame Number
  uint8_t  sf;  // Subframe
  uint8_t  offset;
  uint8_t  period;

  sfn = phy_tti / 10;
  sf  = phy_tti % 10;

  if (sib13_configured) {
    mbsfn_area_info_r9_s* area_info = &mbsfn.mbsfn_area_info;

    offset = area_info->mcch_cfg_r9.mcch_offset_r9;
    period = area_info->mcch_cfg_r9.mcch_repeat_period_r9.to_number();

    if ((sfn % period == offset) && mcch_table[sf] > 0) {
      cfg->mbsfn_area_id           = area_info->mbsfn_area_id_r9;
      cfg->non_mbsfn_region_length = area_info->non_mbsfn_region_len.to_number();
      cfg->mbsfn_mcs               = area_info->mcch_cfg_r9.sig_mcs_r9.to_number();
      cfg->enable                  = true;
      cfg->is_mcch                 = true;
      have_mtch_stop               = false;
      return true;
    }
  }
  return false;
}

bool phy_common::is_mch_subframe(srslte_mbsfn_cfg_t* cfg, uint32_t phy_tti)
{
  uint32_t sfn; // System Frame Number
  uint8_t  sf;  // Subframe
  uint8_t  offset;
  uint8_t  period;

  sfn = phy_tti / 10;
  sf  = phy_tti % 10;

  // Set some defaults
  cfg->mbsfn_area_id           = 0;
  cfg->non_mbsfn_region_length = 1;
  cfg->mbsfn_mcs               = 2;
  cfg->enable                  = false;
  cfg->is_mcch                 = false;
  // Check for MCCH
  if (is_mcch_subframe(cfg, phy_tti)) {
    return true;
  }
  if (not mcch_configured) {
    return false;
  }

  // Not MCCH, check for MCH
  mbsfn_sf_cfg_s*       subfr_cnfg = &mbsfn.mbsfn_subfr_cnfg;
  mbsfn_area_info_r9_s* area_info  = &mbsfn.mbsfn_area_info;

  offset = subfr_cnfg->radioframe_alloc_offset;
  period = subfr_cnfg->radioframe_alloc_period.to_number();

  if (subfr_cnfg->sf_alloc.type() == mbsfn_sf_cfg_s::sf_alloc_c_::types::one_frame) {
    if ((sfn % period == offset) && (mch_table[sf] > 0)) {
      if (sib13_configured) {
        cfg->mbsfn_area_id           = area_info->mbsfn_area_id_r9;
        cfg->non_mbsfn_region_length = area_info->non_mbsfn_region_len.to_number();
        if (mcch_configured) {
          // Iterate through PMCH configs to see which one applies in the current frame
          mbsfn_area_cfg_r9_s* area_r9 = &mbsfn.mcch.msg.c1().mbsfn_area_cfg_r9();

          uint32_t frame_alloc_idx = sfn % area_r9->common_sf_alloc_period_r9.to_number();
          uint32_t mbsfn_per_frame = area_r9->pmch_info_list_r9[0].pmch_cfg_r9.sf_alloc_end_r9 /
                                     +area_r9->pmch_info_list_r9[0].pmch_cfg_r9.mch_sched_period_r9.to_number();
          uint32_t sf_alloc_idx = frame_alloc_idx * mbsfn_per_frame + ((sf < 4) ? sf - 1 : sf - 3);
          while (!have_mtch_stop) {
            pthread_cond_wait(&mtch_cvar, &mtch_mutex);
          }

          for (uint32_t i = 0; i < area_r9->pmch_info_list_r9.size(); i++) {
            if (sf_alloc_idx <= mch_period_stop) {
              cfg->mbsfn_mcs = mbsfn.mcch.msg.c1().mbsfn_area_cfg_r9().pmch_info_list_r9[i].pmch_cfg_r9.data_mcs_r9;
              cfg->enable    = true;
            }
          }
        }
      }
      return true;
    }
  } else if (subfr_cnfg->sf_alloc.type() == mbsfn_sf_cfg_s::sf_alloc_c_::types::four_frames) {
    uint8_t idx = sfn % period;
    if ((idx >= offset) && (idx < offset + 4)) {
      if (mch_table[(idx * 10) + sf] > 0) {
        if (sib13_configured) {
          cfg->mbsfn_area_id           = area_info->mbsfn_area_id_r9;
          cfg->non_mbsfn_region_length = area_info->non_mbsfn_region_len.to_number();
          // TODO: check for MCCH configuration, set MCS and decode
        }
        return true;
      }
    }
  }

  return false;
}

bool phy_common::is_mbsfn_sf(srslte_mbsfn_cfg_t* cfg, uint32_t phy_tti)
{
  return is_mch_subframe(cfg, phy_tti);
}
} // namespace srsenb