/*
 * 
 */


#include "cumsum.h"

/*
 * Global configuration variables. These are set based on command-line
 * arguments, and read-only beyond that point.
 */
static bool ARG_FP_INPUT = false;
static bool ARG_UINT_INPUT = false;
static bool ARG_HELP = false;

static int parse_options(int argc, char*const* argv) {
  int arg_index = 0;
  int arg;
  bool error = false;

  while ((arg = getopt(argc, argv, "frhu")) != -1) {
    switch (arg) {
      case 'f':
        ARG_FP_INPUT = true;
        break;
      case 'u':
        ARG_UINT_INPUT = true;
      case 'h':
        ARG_HELP = true;
        break;
      case '?':
        if (isprint(optopt)) {
          fprintf(stderr, "Unknown option `-%c`.\n", optopt);
        } else {
          fprintf(stderr, "Unknown option character `\\x%x`.\n", optopt);
        }
        error = true;
        break;
      default:
        error = true;
        break;
    }
  }

  if (ARG_UINT_INPUT && ARG_FP_INPUT) {
    fprintf(stderr, "Error: the -u and -f flags are mutually exclusive.\n");
    error = true;
  }

  if (!error) {
    arg_index = optind;
  }

  return arg_index;
}

static void help() {
  fprintf(stderr, "Usage:\ncumsum [-f|-u] [filename]\n");
}

void print_sum(Number sum) {
  if (ARG_FP_INPUT) {
    fprintf(stdout, "%lf\n", sum.d);
  } else if (ARG_UINT_INPUT) {
    fprintf(stdout, "%ld\n", sum.u);
  } else {
    fprintf(stdout, "%ld\n", sum.i);
  }
}

static int read_data_fp(FILE *file, Number *num) {
  double val;
  while (fscanf(file, "%lf ", &val) != EOF) {
    num->d += val;
  }

  return 1;
}

static int read_data_int(FILE *file, Number *num) {
  int64_t val;
  while (fscanf(file, "%ld ", &val) != EOF) {
    num->i += val;
  }

  return 1;
}

static int read_data_uint(FILE *file, Number *num) {
  uint64_t val;
  while (fscanf(file, "%ld ", &val) != EOF) {
    num->u += val;
  }

  return 1;
}

static int process_data(FILE *file) {
  int rc = 1;
  
  Number sum = {};

  /* FIXME: this could probably use a type-based macro to collapse the 
            if statements into a single macro call
   */
  if (ARG_FP_INPUT) {
    rc = read_data_fp(file, &sum);
  } else if (ARG_UINT_INPUT) {
    rc = read_data_uint(file, &sum);
  } else {
    rc = read_data_int(file, &sum);
  }

  if (rc) {
    print_sum(sum);
  }

process_data_end:
  return rc;
}


int main(int argc, char **argv) {
  int rc = EXIT_SUCCESS;
  int file_index = 0;
  if (!(file_index = parse_options(argc, argv))) {
    help();
    rc = EXIT_FAILURE;
    goto program_exit;
  }

  /* if the -h argument is supplied, print usage and exit successfully */
  if (ARG_HELP) {
    help();
    goto program_exit;
  }

  /* open the input file, if one is specified, otherwise default to stdin */
  FILE *input_file;
  if (file_index < argc && strcmp(argv[file_index], "-") != 0) {
    if (!(input_file = fopen(argv[file_index], "r"))) {
      fprintf(stderr, "Error: Unable to open input file %s\n", argv[file_index]);
      rc = EXIT_FAILURE;
      goto program_exit;
    }
  } else {
    input_file = stdin;
  }

  if (!process_data(input_file)) {
    rc = EXIT_FAILURE;
  }

close_file:
  fclose(input_file);

program_exit:
  exit(rc);
}