/**
 *
 * \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 <math.h>
#include <time.h>
#include <stdbool.h>

#include "srslte/srslte.h"

time_t start, finish;
struct timeval x, y;

int num_bits = 1000;
srslte_mod_t modulation = SRSLTE_MOD_BPSK;

void usage(char *prog) {
  printf("Usage: %s [nmse]\n", prog);
  printf("\t-n num_bits [Default %d]\n", num_bits);
  printf("\t-m modulation (1: BPSK, 2: QPSK, 3: QAM16, 4: QAM64) [Default BPSK]\n");  
}

void parse_args(int argc, char **argv) {
  int opt;
  while ((opt = getopt(argc, argv, "nm")) != -1) {
    switch (opt) {
    case 'n':
      num_bits = atoi(argv[optind]);
      break;
    case 'm':
      switch(atoi(argv[optind])) {
      case 1:
        modulation = SRSLTE_MOD_BPSK;
        break;
      case 2:
        modulation = SRSLTE_MOD_QPSK;
        break;
      case 4:
        modulation = SRSLTE_MOD_16QAM;
        break;
      case 6:
        modulation = SRSLTE_MOD_64QAM;
        break;
      default:
        fprintf(stderr, "Invalid modulation %d. Possible values: "
            "(1: BPSK, 2: QPSK, 3: QAM16, 4: QAM64)\n", atoi(argv[optind]));
        break;
      }
      break;
    default:
      usage(argv[0]);
      exit(-1);
    }
  }
}


int main(int argc, char **argv) {
  int i;
  srslte_modem_table_t mod;
  uint8_t *input, *input_bytes, *output;
  cf_t *symbols, *symbols_bytes;
  float *llr, *llr2;

  parse_args(argc, argv);

  /* initialize objects */
  if (srslte_modem_table_lte(&mod, modulation)) {
    fprintf(stderr, "Error initializing modem table\n");
    exit(-1);
  }
  
  srslte_modem_table_bytes(&mod);

  /* check that num_bits is multiple of num_bits x symbol */
  if (num_bits % mod.nbits_x_symbol) {
    fprintf(stderr, "Error num_bits must be multiple of %d\n", mod.nbits_x_symbol);
    exit(-1);
  }

  /* allocate buffers */
  input = srslte_vec_malloc(sizeof(uint8_t) * num_bits);
  if (!input) {
    perror("malloc");
    exit(-1);
  }
  input_bytes = srslte_vec_malloc(sizeof(uint8_t) * num_bits/8);
  if (!input_bytes) {
    perror("malloc");
    exit(-1);
  }
  output = srslte_vec_malloc(sizeof(uint8_t) * num_bits);
  if (!output) {
    perror("malloc");
    exit(-1);
  }
  symbols = srslte_vec_malloc(sizeof(cf_t) * num_bits / mod.nbits_x_symbol);
  if (!symbols) {
    perror("malloc");
    exit(-1);
  }
  symbols_bytes = srslte_vec_malloc(sizeof(cf_t) * num_bits / mod.nbits_x_symbol);
  if (!symbols_bytes) {
    perror("malloc");
    exit(-1);
  }

  llr = srslte_vec_malloc(sizeof(float) * num_bits);
  if (!llr) {
    perror("malloc");
    exit(-1);
  }

  llr2 = srslte_vec_malloc(sizeof(float) * num_bits);
  if (!llr2) {
    perror("malloc");
    exit(-1);
  }

  /* generate random data */
  for (i=0;i<num_bits;i++) {
    input[i] = rand()%2;
  }

  /* modulate */
  struct timeval t[3];
  gettimeofday(&t[1], NULL);
  int ntrials = 100; 
  for (int i=0;i<ntrials;i++) {
    srslte_mod_modulate(&mod, input, symbols, num_bits);
  }
  gettimeofday(&t[2], NULL);
  get_time_interval(t);
  
  printf("Bit: %d us\n", t[0].tv_usec);
  
  /* Test packed implementation */
  srslte_bit_pack_vector(input, input_bytes, num_bits);
  gettimeofday(&t[1], NULL);
  for (int i=0;i<ntrials;i++) {
    srslte_mod_modulate_bytes(&mod, input_bytes, symbols_bytes, num_bits);
  }
  gettimeofday(&t[2], NULL);
  get_time_interval(t);
  
  printf("Byte: %d us\n", t[0].tv_usec);
  
  for (int i=0;i<num_bits/mod.nbits_x_symbol;i++) {
    if (symbols[i] != symbols_bytes[i]) {
      printf("error in symbol %d\n", i);
      exit(-1);
    }
  }
  printf("Symbols OK\n");  
  /* demodulate */
  gettimeofday(&x, NULL);
  srslte_demod_soft_demodulate(modulation, symbols, llr, num_bits / mod.nbits_x_symbol);
  gettimeofday(&y, NULL);
  printf("\nElapsed time [ns]: %d\n", (int) y.tv_usec - (int) x.tv_usec);
  
  for (i=0;i<num_bits;i++) {
    output[i] = llr[i]>=0 ? 1 : 0;
  }

  /* check errors */
  for (i=0;i<num_bits;i++) {
    if (input[i] != output[i]) {
      fprintf(stderr, "Error in bit %d\n", i);
      exit(-1);
    }
  }

  free(llr);
  free(symbols);
  free(symbols_bytes);
  free(output);
  free(input);
  free(input_bytes);

  srslte_modem_table_free(&mod);

  printf("Ok\n");
  exit(0);
}