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

#include "util/versie.h"
#include "util/loop_args.h"
#include "io/read_file.h"

static void usage(FILE *f) {
  fprintf(f,
      "Gebruik: kat [-hV] <bestand...>\n"
      "\n"
      "Schakel bestanden aaneen naar standaard uitvoer.\n"
      "\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) {
  int opt;
  while ((opt = getopt(argc, argv, "hV")) != -1) {
    switch (opt) {
      case 'h':
        usage(stdout);
        exit(0);

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

      case '?':
        fprintf(stderr, "kat: Ongeldige optie: -%c\n", optopt);
        usage(stderr);
        exit(1);
    }
  }

  return argv + optind;
}

static int process(char *fname, bool isstdin) {
#define BUF_SIZE 4096

  static char buf[BUF_SIZE];

  FILE *stream = isstdin ? stdin : fopen(fname, "rb");

  while (!feof(stream)) {
    const size_t n = fread(buf, 1, BUF_SIZE, stream);
    fwrite(buf, 1, n, stdout);
  }

  if (!isstdin) fclose(stream);
  return 0;

#undef BUF_SIZE
}

int entry_kat(int argc, char **argv) {
  char **args = parse_options(argc, argv);
  return loop_args(args, process);
}