/**
 *
 * \section COPYRIGHT
 *
 * Copyright 2013-2014 The libLTE Developers. See the
 * COPYRIGHT file at the top-level directory of this distribution.
 *
 * \section LICENSE
 *
 * This file is part of the libLTE library.
 *
 * libLTE is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * libLTE 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 Lesser General Public License for more details.
 *
 * A copy of the GNU Lesser 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 <math.h>
#include <complex.h>
#include <sys/time.h>
#include <unistd.h>
#include <assert.h>
#include <signal.h>

#include "liblte/phy/phy.h"

#include "liblte/cuhd/cuhd.h"
void *uhd;

int nof_frames_total = CS_DEFAULT_NOFFRAMES_TOTAL;
int nof_frames_detected = CS_DEFAULT_NOFFRAMES_DETECTED;
float threshold = -1; 

float uhd_freq = 0.0, uhd_gain = 20.0;
char *uhd_args = "";

void usage(char *prog) {
  printf("Usage: %s [agntdv] -f uhd_freq\n", prog);
  printf("\t-a UHD args [Default %s]\n", uhd_args);
  printf("\t-g UHD RX gain [Default %.2f dB]\n", uhd_gain);
  printf("\t-n nof_frames_total [Default 100]\n");
  printf("\t-d nof_frames_detected [Default 10]\n");
  printf("\t-t threshold [Default %.2f]\n",threshold);
  printf("\t-v [set verbose to debug, default none]\n");
}

void parse_args(int argc, char **argv) {
  int opt;
  while ((opt = getopt(argc, argv, "agndtvf")) != -1) {
    switch (opt) {
    case 'n':
      nof_frames_total = atoi(argv[optind]);
      break;
    case 'd':
      nof_frames_detected = atoi(argv[optind]);
      break;
    case 'a':
      uhd_args = argv[optind];
      break;
    case 'g':
      uhd_gain = atof(argv[optind]);
      break;
    case 'f':
      uhd_freq = atof(argv[optind]);
      break;
    case 't':
      threshold = atof(argv[optind]);
      break;
    case 'v':
      verbose++;
      break;
    default:
      usage(argv[0]);
      exit(-1);
    }
  }
  if (uhd_freq == 0.0) {
    usage(argv[0]);
    exit(-1);
  }
}

void input_init() {

  printf("Opening UHD device...\n");
  if (cuhd_open(uhd_args, &uhd)) {
    fprintf(stderr, "Error opening uhd\n");
    exit(-1);
  }  
  cuhd_set_rx_gain(uhd, uhd_gain);
  
  /* set uhd_freq */
  cuhd_set_rx_freq(uhd, (double) uhd_freq);
  cuhd_rx_wait_lo_locked(uhd);
  DEBUG("Set uhd_freq to %.3f MHz\n", (double ) uhd_freq/1000000);
  
  INFO("Setting sampling frequency 960 KHz for PSS search\n", 0);
  cuhd_set_rx_srate(uhd, 960000.0);

  DEBUG("Starting receiver...\n", 0);
  cuhd_start_rx_stream(uhd);

}

int main(int argc, char **argv) {
  ue_cellsearch_t s; 
  ue_mib_t uemib;
  ue_cellsearch_result_t found_cell;
  pbch_mib_t mib; 
  uint32_t flen; 
  cf_t *buffer; 
  int n; 
  
  parse_args(argc, argv);
    
  input_init();
    
  // allocate for the maximum size (10 ms at 1.92 MHz for PBCH decoding)
  buffer = vec_malloc(sizeof(cf_t) * 19200*30);
  if (!buffer) {
    perror("malloc"); 
    exit(-1);
  }
          
  if (ue_cellsearch_init(&s)) {
    fprintf(stderr, "Error initiating UE sync module\n");
    exit(-1);
  }
  if (threshold > 0) {
    ue_cellsearch_set_threshold(&s, threshold);    
  }
  
  if (nof_frames_total > 0) {
    ue_cellsearch_set_nof_frames_total(&s, nof_frames_total);
  }
  if (nof_frames_detected > 0) {
    ue_cellsearch_set_nof_frames_detected(&s, nof_frames_detected);
  }

  uint32_t nof_scanned_cells = 0; 
  flen = 4800; 
  
  do {
    
    if (cuhd_recv(uhd, buffer, flen, 1)<0) {
      fprintf(stderr, "Error receiving from USRP\n");
      exit(-1);
    }
    
    n = ue_cellsearch_scan(&s, buffer, flen, &found_cell);
    switch(n) {
      case CS_FRAME_UNALIGNED:
        fprintf(stderr, "Unaliged frame!! Exiting\n");
        exit(-1);
      case CS_CELL_DETECTED:
        printf("\tCELL ID: %d, CP: %s, Peak: %.2f, Mode: %d/%d\n", 
               found_cell.cell_id, lte_cp_string(found_cell.cp), 
               found_cell.peak, found_cell.mode, s.nof_frames_detected);            
        
        nof_scanned_cells++;
        break;
      case CS_CELL_NOT_DETECTED:
        nof_scanned_cells++;
        break;
      case LIBLTE_ERROR:
      case LIBLTE_ERROR_INVALID_INPUTS: 
        fprintf(stderr, "Error calling cellsearch_scan()\n");
        exit(-1);        
    }
  } while(nof_scanned_cells < 3 && n != CS_CELL_DETECTED);
  
  if (n == CS_CELL_DETECTED) {
    INFO("Stopping receiver...\n", 0);
    cuhd_stop_rx_stream(uhd);
    
    cuhd_flush_buffer(uhd);
    
    if (ue_mib_init(&uemib, found_cell.cell_id, found_cell.cp)) {
      fprintf(stderr, "Error initiating PBCH decoder\n");
      exit(-1);
    }

    INFO("Setting sampling frequency 1.92 MHz for PBCH decoding\n", 0);
    cuhd_set_rx_srate(uhd, 1920000.0);
    INFO("Starting receiver...\n", 0);
    cuhd_start_rx_stream(uhd);
    
    usleep(50000);
            
    uint32_t nof_frames = 0;
    flen = MIB_FRAME_SIZE;
    
    do {
      if (cuhd_recv(uhd, buffer, flen, 1)<0) {
        fprintf(stderr, "Error receiving from USRP\n");
        exit(-1);
      }      
      
      INFO("Calling ue_mib_decode() %d/%d\n", nof_frames, nof_frames_total);
      
      n = ue_mib_decode(&uemib, buffer, flen, &mib);
      if (n == LIBLTE_ERROR || n == LIBLTE_ERROR_INVALID_INPUTS) {
        fprintf(stderr, "Error calling ue_mib_decode()\n");
        exit(-1);
      }
      if (n == MIB_FRAME_UNALIGNED) {
        printf("Realigning frame\n");
        if (cuhd_recv(uhd, buffer, flen/2, 1)<0) {
          fprintf(stderr, "Error receiving from USRP\n");
          exit(-1);
        }
      }
      nof_frames++;
    } while (n != MIB_FOUND && nof_frames < nof_frames_total);
    if (n == MIB_FOUND) {
      printf("\n\nMIB decoded in %d ms (%d half frames)\n", nof_frames*5, nof_frames);
      pbch_mib_fprint(stdout, &mib, found_cell.cell_id);
    } else {
      printf("\nCould not decode MIB\n");
    }
  }
  
  
  
  ue_mib_free(&uemib);
  ue_cellsearch_free(&s);
  cuhd_close(uhd);
  exit(0);
}