/**
 *
 * \section COPYRIGHT
 *
 * Copyright 2013-2015 Software Radio Systems Limited
 *
 * \section LICENSE
 *
 * This file is part of the srsLTE library.
 *
 * 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>

#include "srslte/srslte.h"

char *input_file_name = NULL;

srslte_cell_t cell = {
  6,            // nof_prb
  2,            // nof_ports
  150,          // cell_id  
  SRSLTE_CP_NORM,       // cyclic prefix
  SRSLTE_PHICH_R_1,          // PHICH resources      
  SRSLTE_PHICH_NORM    // PHICH length
};

int nof_frames = 1; 

uint8_t bch_payload_file[SRSLTE_BCH_PAYLOAD_LEN] = {0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

#define FLEN  (10*SRSLTE_SF_LEN(srslte_symbol_sz(cell.nof_prb)))

srslte_filesource_t fsrc;
cf_t *input_buffer, *fft_buffer, *ce[SRSLTE_MAX_PORTS];
srslte_pbch_t pbch;
srslte_ofdm_t fft;
srslte_chest_dl_t chest;

void usage(char *prog) {
  printf("Usage: %s [vcoe] -i input_file\n", prog);
  printf("\t-c cell_id [Default %d]\n", cell.id);
  printf("\t-p nof_prb [Default %d]\n", cell.nof_prb);
  printf("\t-e Set extended prefix [Default Normal]\n");
  printf("\t-n nof_frames [Default %d]\n", nof_frames);
  printf("\t-v [set srslte_verbose to debug, default none]\n");
}

void parse_args(int argc, char **argv) {
  int opt;

  while ((opt = getopt(argc, argv, "ivcpne")) != -1) {
    switch(opt) {
    case 'i':
      input_file_name = argv[optind];
      break;
    case 'c':
      cell.id = atoi(argv[optind]);
      break;
    case 'p':
      cell.nof_prb = atoi(argv[optind]);
      break;
    case 'n':
      nof_frames = atoi(argv[optind]);
      break;
    case 'v':
      srslte_verbose++;
      break;
    case 'e':
      cell.cp = SRSLTE_CP_EXT;
      break;
    default:
      usage(argv[0]);
      exit(-1);
    }
  }
  if (!input_file_name) {
    usage(argv[0]);
    exit(-1);
  }
}

int base_init() {
  int i;

  if (srslte_filesource_init(&fsrc, input_file_name, SRSLTE_COMPLEX_FLOAT_BIN)) {
    fprintf(stderr, "Error opening file %s\n", input_file_name);
    exit(-1);
  }

  input_buffer = malloc(FLEN * sizeof(cf_t));
  if (!input_buffer) {
    perror("malloc");
    exit(-1);
  }

  fft_buffer = malloc(SRSLTE_SF_LEN_RE(cell.nof_prb, cell.cp) * sizeof(cf_t));
  if (!fft_buffer) {
    perror("malloc");
    return -1;
  }

  for (i=0;i<cell.nof_ports;i++) {
    ce[i] = malloc(SRSLTE_SF_LEN_RE(cell.nof_prb, cell.cp) * sizeof(cf_t));
    if (!ce[i]) {
      perror("malloc");
      return -1;
    }
  }
  
  if (!srslte_cell_isvalid(&cell)) {
    fprintf(stderr, "Invalid cell properties\n");
    return -1;
  }

  if (srslte_chest_dl_init(&chest, cell)) {
    fprintf(stderr, "Error initializing equalizer\n");
    return -1;
  }

  if (srslte_ofdm_init_(&fft, cell.cp, srslte_symbol_sz_power2(cell.nof_prb), cell.nof_prb, SRSLTE_DFT_FORWARD)) {
    fprintf(stderr, "Error initializing FFT\n");
    return -1;
  }

  if (srslte_pbch_init(&pbch, cell)) {
    fprintf(stderr, "Error initiating PBCH\n");
    return -1;
  }

  DEBUG("Memory init OK\n",0);
  return 0;
}

void base_free() {
  int i;

  srslte_filesource_free(&fsrc);

  free(input_buffer);
  free(fft_buffer);

  srslte_filesource_free(&fsrc);
  for (i=0;i<cell.nof_ports;i++) {
    free(ce[i]);
  }
  srslte_chest_dl_free(&chest);
  srslte_ofdm_rx_free(&fft);

  srslte_pbch_free(&pbch);
}

int main(int argc, char **argv) {
  uint8_t bch_payload[SRSLTE_BCH_PAYLOAD_LEN];
  int n;
  uint32_t nof_tx_ports; 
  int sfn_offset; 
  cf_t *ce_slot1[SRSLTE_MAX_PORTS]; 
  
  if (argc < 3) {
    usage(argv[0]);
    exit(-1);
  }

  parse_args(argc,argv);

  if (base_init()) {
    fprintf(stderr, "Error initializing receiver\n");
    exit(-1);
  }

  int frame_cnt = 0; 
  int nof_decoded_mibs = 0; 
  int nread = 0; 
  do {
    nread = srslte_filesource_read(&fsrc, input_buffer, FLEN);

    if (nread > 0) {
      // process 1st subframe only
      srslte_ofdm_rx_sf(&fft, input_buffer, fft_buffer);

      /* Get channel estimates for each port */
      srslte_chest_dl_estimate(&chest, fft_buffer, ce, 0);

      INFO("Decoding PBCH\n", 0);
      
      for (int i=0;i<SRSLTE_MAX_PORTS;i++) {
        ce_slot1[i] = &ce[i][SRSLTE_SLOT_LEN_RE(cell.nof_prb, cell.cp)];
      }

      srslte_pbch_decode_reset(&pbch);
      n = srslte_pbch_decode(&pbch, &fft_buffer[SRSLTE_SLOT_LEN_RE(cell.nof_prb, cell.cp)], 
                      ce_slot1, srslte_chest_dl_get_noise_estimate(&chest), 
                      bch_payload, &nof_tx_ports, &sfn_offset);
      if (n == 1) {
        nof_decoded_mibs++;
      } else if (n < 0) {
        fprintf(stderr, "Error decoding PBCH\n");
        exit(-1);
      }
      frame_cnt++;
    } else if (nread < 0) {
      fprintf(stderr, "Error reading from file\n");
      exit(-1);
    }
  } while(nread > 0 && frame_cnt < nof_frames);

  base_free();
  if (frame_cnt == 1) {
    if (n == 0) {
      printf("Could not decode PBCH\n");
      exit(-1);
    } else {
      printf("MIB decoded OK. Nof ports: %d. SFN offset: %d Payload: ", nof_tx_ports, sfn_offset);    
      srslte_vec_fprint_hex(stdout, bch_payload, SRSLTE_BCH_PAYLOAD_LEN);
      if (nof_tx_ports == 2 && sfn_offset == 0 && !memcmp(bch_payload, bch_payload_file, SRSLTE_BCH_PAYLOAD_LEN)) {
        printf("This is the signal.1.92M.dat file\n");
        exit(0);
      } else {
        printf("This is an unknown file\n");
        exit(-1);
      }
    }
  } else {
    printf("Decoded %d/%d MIBs\n", nof_decoded_mibs, frame_cnt);
  }
}