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

#include "util/versie.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 void process(struct filebuf *fb) {
  fwrite(fb->buf, 1, fb->sz, stdout);
  free_filebuf(fb);
}

// TODO: be smarter, kat doesn't have to read the whole file in memory (for
// unmappable files)

int entry_kat(int argc, char **argv) {
  char **args = parse_options(argc, argv);

  if (*args == NULL) {
    struct filebuf *fb = stream_to_filebuf(stdin, 0);
    if (fb == NULL) goto err_stdin;

    process(fb);
    return 0;
  }

  while (*args != NULL) {
    struct filebuf *fb = NULL;

    if (!strcmp(*args, "-")) {
      fb = stream_to_filebuf(stdin, 0);
      if (fb == NULL) goto err_stdin;
    } else {
      bool isdir = false;
      fb = file_to_filebuf(*args, 0, &isdir);
      if (isdir) goto err_isdir;
      else if (fb == NULL) goto err_file;
    }

    process(fb);

    args++;
  }

  return 0;

err_stdin:
  fprintf(stderr, "kat: fout bij lezen van standaard invoer\n");
  return 1;

err_file:
  fprintf(stderr, "kat: fout bij lezen van bestand\n");
  return 1;

err_isdir:
  fprintf(stderr, "kat: bestand '%s' is een mapje\n", *args);
  return 1;
}