#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "util/versie.h"

static void usage(FILE *f) {
  fprintf(f,
      "Gebruik: rn [-hV] [BESTAND]...\n"
      "\n"
      "Nummereer elke regel van elk BESTAND.\n"
      "Als geen bestanden gegeven zijn, of het bestand is -, nummereer dan standaard invoer.\n"
      "\n"
      "  -p    Regelnummers per BESTAND.\n"
      "  -h    Toon deze hulptekst\n"
      "  -V    Toon versienummer\n");
}

// Returns pointer to argument array containing the file names
static char** parse_options(int argc, char **argv, bool *perFile) {
  int opt;
  while ((opt = getopt(argc, argv, "phV")) != -1) {
    switch (opt) {
      case 'p':
        *perFile = true;
        break;

      case 'h':
        usage(stdout);
        exit(0);

      case 'V':
        drukkedoos_print_versie(stdout);
        exit(0);

      case '?':
        usage(stderr);
        exit(1);
    }
  }

  return argv + optind;
}

static void process(const char *fname, FILE *file, bool perFile, size_t *n) {
  if (perFile) *n = 1;

  char *line = NULL;
  size_t linen = 0;

  ssize_t nread = 0;
  while ((errno = 0, nread = getline(&line, &linen, file)) != -1) {
    printf("%6lu  %s", *n, line);
    *n += 1;
  }

  free(line);

  if (errno != 0) {
    printf("tak: fout bij lezen uit bestand '%s'\n", fname);
    exit(1);
  }
}

int entry_rn(int argc, char **argv) {
  bool perFile = false;
  char **args = parse_options(argc, argv, &perFile);

  size_t n = 1;

  if (*args == NULL) {
    process("stdin", stdin, perFile, &n);
    return 0;
  }

  while (*args != NULL) {
    if (!strcmp(*args, "-")) {
      process("stdin", stdin, perFile, &n);
    } else {
      FILE *file = fopen(*args, "r");
      if (file == NULL) {
        fprintf(stderr, "rn: %s: kon bestand niet openen\n", *args);
        return 1;
      }

      process(*args, file, perFile, &n);
      fclose(file);
    }

    args++;
  }

  return 0;
}