/*
 * UNG's Not GNU
 * 
 * Copyright (c) 2011, Jakob Kaivo <jakob@kaivo.net>
 * 
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

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

const char *split_desc = "split files into pieces";
const char *split_inv  = "split [-l line_count] [-a suffix_length] [file[name]]\nsplit -b n[k|m] [-a suffix_length] [file[name]]";

static unsigned long power (int base, int power)
{
  unsigned long r = base;
  if (power < 1)
    return 1;
  for (r = base; power > 1; power--)
    r *= r;
  return r;
}

static int split (const char *in, const char *base, int suffix, unsigned int lines, unsigned long bytes)
{
  FILE *f = stdin;
  FILE *o = NULL;
  char oname[FILENAME_MAX];
  int chunk = 0;
  int i;
  char *buf;
  size_t len;
  size_t nread;

  if (strcmp ("-", in))
    f = fopen (in, "r");

  if (bytes > 0)
    buf = malloc (bytes);
  else
    buf = malloc (BUFSIZ);

  memset (oname, '\0', FILENAME_MAX);
  strcpy (oname, base);

  while (!feof (f)) {
    if (chunk >= power(26, suffix))
      return 2; // to much data

    for (i = suffix; i > 0; i--)
      oname[strlen(base) + suffix - i] = ((chunk % power(26,i)) / power(26,i-1)) + 'a';
    o = fopen (oname, "w");

    if (lines > 0) {
      for (i = lines; !feof(f) && i > 0; i--) {
        if ((nread = getline (&buf, &len, f)) != -1)
          fwrite (buf, sizeof(char), nread, o);
      }
    } else {
      if ((nread = fread (buf, sizeof(char), bytes, f)) != -1)
        fwrite (buf, sizeof(char), nread, o);
    }

    fclose (o);
    chunk++;
  }

  if (strcmp ("-", in))
    fclose (f);
}

int
main(int argc, char **argv)
{
  int c;
  unsigned int lines = 0;
  unsigned long bytes = 0;
  int suffix = 2;
  char *end;

  while ((c = getopt (argc, argv, ":l:a:b:")) != -1) {
    switch (c) {
      case 'l':
        if (bytes != 0)
          return 1;
        lines = strtol (optarg, &end, 10);
        if (end != NULL && strlen (end) > 0)
          return 1;
        break;
      case 'a':
        suffix = strtol (optarg, &end, 10);
        if (end != NULL && strlen (end) > 0)
          return 1;
        break;
      case 'b':
        if (lines != 0)
          return 1;
        bytes = strtol (optarg, &end, 10);
        if (end != NULL) {
          if (!strcmp ("k", end))
            bytes *= 1024;
          else if (!strcmp ("m", end))
            bytes *= 1048576;
	  else
            return 1;
        }
        break;
      default:
        return 1;
    }
  }

  if (lines == 0 && bytes == 0)
    lines = 1000;
  
  if (optind >= argc)
    split ("-", "x", suffix, lines, bytes);
  else if (optind == argc - 1)
    split (argv[optind], "x", suffix, lines, bytes);
  else if (optind == argc - 2)
    split (argv[optind], argv[optind+1], suffix, lines, bytes);
  else
    return 1;

  return 0;
}