/*
 * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The OpenAirInterface Software Alliance licenses this file to You under
 * the OAI Public License, Version 1.1  (the "License"); you may not use this file
 * except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.openairinterface.org/?page_id=698
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *-------------------------------------------------------------------------------
 * For more information about the OpenAirInterface (OAI) Software Alliance:
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 */

/*! \file PHY/NR_ESTIMATION/nr_measurements_gNB.c
* \brief gNB measurement routines
* \author Ahmed Hussein, G. Casati, K. Saaifan
* \date 2019
* \version 0.1
* \company Fraunhofer IIS
* \email: ahmed.hussein@iis.fraunhofer.de, guido.casati@iis.fraunhofer.de, khodr.saaifan@iis.fraunhofer.de
* \note
* \warning
*/

#include "PHY/types.h"
#include "PHY/defs_gNB.h"
#include "nr_ul_estimation.h"

#define I0_SKIP_DC 1

extern openair0_config_t openair0_cfg[MAX_CARDS];

void nr_est_timing_advance_pusch(const NR_DL_FRAME_PARMS *frame_parms, const int32_t *ul_ch_estimates_time, struct delay_s *delay)
{
  int max_pos = delay->pusch_delay_max_pos;
  int max_val = delay->pusch_delay_max_val;
  const int sync_pos = 0;

  for (int i = 0; i < frame_parms->ofdm_symbol_size; i++) {
    int Re = ((int16_t *)ul_ch_estimates_time)[(i << 1)];
    int Im = ((int16_t *)ul_ch_estimates_time)[1 + (i << 1)];
    int temp = (Re * Re / 2) + (Im * Im / 2);
    if (temp > max_val) {
      max_pos = i;
      max_val = temp;
    }
  }

  if (max_pos > frame_parms->ofdm_symbol_size / 2)
    max_pos = max_pos - frame_parms->ofdm_symbol_size;

  delay->pusch_delay_max_pos = max_pos;
  delay->pusch_delay_max_val = max_val;
  delay->pusch_est_delay = max_pos - sync_pos;
}

int nr_est_timing_advance_srs(const NR_DL_FRAME_PARMS *frame_parms, 
                              const int32_t srs_estimated_channel_time[][frame_parms->ofdm_symbol_size]) {
  int timing_advance = 0;
  int max_val = 0;

  for (int i = 0; i < frame_parms->ofdm_symbol_size; i++) {
    int temp = 0;
    for (int aa = 0; aa < frame_parms->nb_antennas_rx; aa++) {
      int Re = ((c16_t*)srs_estimated_channel_time[aa])[i].r;
      int Im = ((c16_t*)srs_estimated_channel_time[aa])[i].i;
      temp += (Re*Re/2) + (Im*Im/2);
    }
    if (temp > max_val) {
      timing_advance = i;
      max_val = temp;
    }
  }

  if (timing_advance > frame_parms->ofdm_symbol_size/2) {
    timing_advance = timing_advance - frame_parms->ofdm_symbol_size;
  }

  // Scale the 16 factor in N_TA calculation in 38.213 section 4.2 according to the used FFT size
  const uint16_t bw_scaling = frame_parms->ofdm_symbol_size >> 7;

  // do some integer rounding to improve TA accuracy
  int sync_pos_rounded;
  if (timing_advance > 0) {
    sync_pos_rounded = timing_advance + (bw_scaling >> 1) - 1;
  } else {
    sync_pos_rounded = timing_advance - (bw_scaling >> 1) + 1;
  }

  int timing_advance_update = sync_pos_rounded / bw_scaling;

  // put timing advance command in 0..63 range
  timing_advance_update += 31;

  if (timing_advance_update < 0)  timing_advance_update = 0;
  if (timing_advance_update > 63) timing_advance_update = 63;

  return timing_advance_update;
}

void dump_nr_I0_stats(FILE *fd,PHY_VARS_gNB *gNB) {


    int min_I0=1000,max_I0=0;
    int amin=0,amax=0;
    fprintf(fd,"Blacklisted PRBs %d/%d\n",gNB->num_ulprbbl,gNB->frame_parms.N_RB_UL);
    for (int i=0; i<gNB->frame_parms.N_RB_UL; i++) {
      if (gNB->ulprbbl[i] > 0) continue;	    

      if (gNB->measurements.n0_subband_power_tot_dB[i]<min_I0) {min_I0 = gNB->measurements.n0_subband_power_tot_dB[i]; amin=i;}

      if (gNB->measurements.n0_subband_power_tot_dB[i]>max_I0) {max_I0 = gNB->measurements.n0_subband_power_tot_dB[i]; amax=i;}
    }

    for (int i=0; i<gNB->frame_parms.N_RB_UL; i++) {
     if (gNB->ulprbbl[i] ==0) fprintf(fd,"%2d.",gNB->measurements.n0_subband_power_tot_dB[i]-gNB->measurements.n0_subband_power_avg_dB);
     else fprintf(fd," X."); 
     if (i%25 == 24) fprintf(fd,"\n");
    }
    fprintf(fd,"\n");
    fprintf(fd,"max_IO = %d (%d), min_I0 = %d (%d), avg_I0 = %d dB",max_I0,amax,min_I0,amin,gNB->measurements.n0_subband_power_avg_dB);
    if (gNB->frame_parms.nb_antennas_rx>1) {
       fprintf(fd,"(");
       for (int aarx=0;aarx<gNB->frame_parms.nb_antennas_rx;aarx++)
         fprintf(fd,"%d.",gNB->measurements.n0_subband_power_avg_perANT_dB[aarx]);
       fprintf(fd,")");
    }
    fprintf(fd,"\nPRACH I0 = %d.%d dB\n",gNB->measurements.prach_I0/10,gNB->measurements.prach_I0%10);


}



void gNB_I0_measurements(PHY_VARS_gNB *gNB,int slot, int first_symb,int num_symb) {

  NR_DL_FRAME_PARMS *frame_parms = &gNB->frame_parms;
  NR_gNB_COMMON *common_vars = &gNB->common_vars;
  PHY_MEASUREMENTS_gNB *measurements = &gNB->measurements;
  int rb, nb_symb[275]={0};

  memset(measurements->n0_subband_power, 0, sizeof(measurements->n0_subband_power));

  for (int s=first_symb;s<(first_symb+num_symb);s++) {
    int offset0 = ((slot&3)*frame_parms->symbols_per_slot + s) * frame_parms->ofdm_symbol_size;
    for (rb=0; rb<frame_parms->N_RB_UL; rb++) {
      if ((gNB->rb_mask_ul[s][rb >> 5] & (1U << (rb & 31))) == 0 && // check that rb was not used in this subframe
          !(I0_SKIP_DC && rb == frame_parms->N_RB_UL>>1)) {         // skip middle PRB because of artificial noise possibly created by FFT
        int offset = offset0 + (frame_parms->first_carrier_offset + (rb*12))%frame_parms->ofdm_symbol_size;
        nb_symb[rb]++;
        for (int aarx=0; aarx<frame_parms->nb_antennas_rx; aarx++) {
          int32_t *ul_ch = &common_vars->rxdataF[aarx][offset];
          int32_t signal_energy;
          if (((frame_parms->N_RB_UL&1) == 1) &&
              (rb==(frame_parms->N_RB_UL>>1))) {
            signal_energy = signal_energy_nodc(ul_ch, 6);
            ul_ch = &common_vars->rxdataF[aarx][offset0];
            signal_energy += signal_energy_nodc(ul_ch, 6);
          } else {
            signal_energy = signal_energy_nodc(ul_ch, 12);
          }
          measurements->n0_subband_power[aarx][rb] += signal_energy;
          LOG_D(PHY,"slot %d symbol %d RB %d aarx %d n0_subband_power %d\n", slot, s, rb, aarx, signal_energy);
        } //antenna
      }
    } //rb
  } // symb
  int nb_rb=0;
  int32_t n0_subband_tot=0;
  int32_t n0_subband_tot_perANT[frame_parms->nb_antennas_rx];

  memset(n0_subband_tot_perANT, 0, sizeof(n0_subband_tot_perANT));

  for (int rb = 0 ; rb<frame_parms->N_RB_UL;rb++) {
    int32_t n0_subband_tot_perPRB=0;
    if (nb_symb[rb] > 0) {
      for (int aarx=0;aarx<frame_parms->nb_antennas_rx;aarx++) {
        measurements->n0_subband_power[aarx][rb]/=nb_symb[rb];
        measurements->n0_subband_power_dB[aarx][rb] = dB_fixed(measurements->n0_subband_power[aarx][rb]);
        n0_subband_tot_perPRB+=measurements->n0_subband_power[aarx][rb];
        n0_subband_tot_perANT[aarx]+=measurements->n0_subband_power[aarx][rb];
      }
      n0_subband_tot_perPRB/=frame_parms->nb_antennas_rx;
      measurements->n0_subband_power_tot_dB[rb] = dB_fixed(n0_subband_tot_perPRB);
      measurements->n0_subband_power_tot_dBm[rb] = measurements->n0_subband_power_tot_dB[rb] - gNB->rx_total_gain_dB - dB_fixed(frame_parms->N_RB_UL);
      LOG_D(PHY,"n0_subband_power_tot_dB[%d] => %d, over %d symbols\n",rb,measurements->n0_subband_power_tot_dB[rb],nb_symb[rb]);
      n0_subband_tot += n0_subband_tot_perPRB;
      nb_rb++;
    }
  }
  if (nb_rb>0) {
     measurements->n0_subband_power_avg_dB = dB_fixed(n0_subband_tot/nb_rb);
     for (int aarx=0;aarx<frame_parms->nb_antennas_rx;aarx++) {
       measurements->n0_subband_power_avg_perANT_dB[aarx] = dB_fixed(n0_subband_tot_perANT[aarx]/nb_rb);
     }
  }
}


// Scope: This function computes the UL SNR from the UL channel estimates
//
// Todo:
// - averaging IIR filter for RX power and noise
void nr_gnb_measurements(PHY_VARS_gNB *gNB, uint8_t ulsch_id, unsigned char harq_pid, unsigned char symbol, uint8_t nrOfLayers){

  int rx_power_tot[NUMBER_OF_NR_ULSCH_MAX];
  int rx_power[NUMBER_OF_NR_ULSCH_MAX][NB_ANTENNAS_RX];
  unsigned short rx_power_avg_dB[NUMBER_OF_NR_ULSCH_MAX];
  unsigned short rx_power_tot_dB[NUMBER_OF_NR_ULSCH_MAX];

  double             rx_gain = openair0_cfg[0].rx_gain[0];
  double      rx_gain_offset = openair0_cfg[0].rx_gain_offset[0];
  PHY_MEASUREMENTS_gNB *meas = &gNB->measurements;
  NR_DL_FRAME_PARMS      *fp = &gNB->frame_parms;
  int              ch_offset = fp->ofdm_symbol_size * symbol;
  int                N_RB_UL = gNB->ulsch[ulsch_id]->harq_processes[harq_pid]->ulsch_pdu.rb_size;

  rx_power_tot[ulsch_id] = 0;

  for (int aarx = 0; aarx < fp->nb_antennas_rx; aarx++){

    rx_power[ulsch_id][aarx] = 0;

    for (int aatx = 0; aatx < nrOfLayers; aatx++){

      meas->rx_spatial_power[ulsch_id][aatx][aarx] = (signal_energy_nodc(&gNB->pusch_vars[ulsch_id]->ul_ch_estimates[aatx*fp->nb_antennas_rx+aarx][ch_offset], N_RB_UL * NR_NB_SC_PER_RB));

      if (meas->rx_spatial_power[ulsch_id][aatx][aarx] < 0) {
        meas->rx_spatial_power[ulsch_id][aatx][aarx] = 0;
      }

      meas->rx_spatial_power_dB[ulsch_id][aatx][aarx] = (unsigned short) dB_fixed(meas->rx_spatial_power[ulsch_id][aatx][aarx]);
      rx_power[ulsch_id][aarx] += meas->rx_spatial_power[ulsch_id][aatx][aarx];

    }
    LOG_D(PHY, "[ULSCH ID %d] RX power in antenna %d = %d\n", ulsch_id, aarx, rx_power[ulsch_id][aarx]);

    rx_power_tot[ulsch_id] += rx_power[ulsch_id][aarx];

  }

  rx_power_tot_dB[ulsch_id] = (unsigned short) dB_fixed(rx_power_tot[ulsch_id]);
  rx_power_avg_dB[ulsch_id] = rx_power_tot_dB[ulsch_id];

  meas->wideband_cqi_tot[ulsch_id] = dB_fixed2(rx_power_tot[ulsch_id], meas->n0_power_tot);
  meas->rx_rssi_dBm[ulsch_id] = rx_power_avg_dB[ulsch_id] + 30 - 10 * log10(pow(2, 30)) - (rx_gain - rx_gain_offset) - dB_fixed(fp->ofdm_symbol_size);

  LOG_D(PHY, "[ULSCH %d] RSSI %d dBm/RE, RSSI (digital) %d dB (N_RB_UL %d), WBand CQI tot %d dB, N0 Power tot %d, RX Power tot %d\n",
    ulsch_id,
    meas->rx_rssi_dBm[ulsch_id],
    rx_power_avg_dB[ulsch_id],
    N_RB_UL,
    meas->wideband_cqi_tot[ulsch_id],
    meas->n0_power_tot,
    rx_power_tot[ulsch_id]);

}
