/* $Id: split_unrmailed_RMAIL.c 6 2006-03-13 02:00:20Z flaterco $ */

/* Turn the results of the Emacs command unrmail into individual messages,
   undoing RMAIL damage to From lines along the way. */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <sys/types.h>
#include <sys/stat.h>

#define bufsize 10000

FILE *newmsg (char *dest_dir) {
  static unsigned long serialnum = 0;
  size_t l;
  char msgfilename[bufsize];
  FILE *fp;
  struct stat stat_struct;

  l = strlen(dest_dir);
  assert (l + 80 < bufsize);
  strcpy (msgfilename, dest_dir);
  if (msgfilename[l-1] != '/')
    msgfilename[l++] = '/';
  do
    sprintf (msgfilename+l, "msg%lu", serialnum++);
  while (stat (msgfilename, &stat_struct) == 0);
  if (!(fp = fopen (msgfilename, "w"))) {
    perror (msgfilename);
    fprintf (stderr, "Aborting run\n");
    exit (-1);
  }
  return fp;
}

int main (int argc, char **argv) {
  FILE *mbox, *msg=NULL;
  char inbuf[bufsize];
  if (argc != 3) {
    fprintf (stderr, "Usage:  split_unrmailed_RMAIL mailbox-filename destination-directory\n");
    exit (-1);
  }
  if (!(mbox = fopen (argv[1], "r"))) {
    perror (argv[1]);
    exit (-1);
  }
  while (fgets (inbuf, bufsize, mbox)) {
    if (!(strncmp (inbuf, "From ", 5))) {
      if (msg)
        fclose (msg);
      msg = newmsg (argv[2]);
      /* Hack to undo the RMAIL mangling of From line */
      /* (just throw out the coding system line) */
      assert ((fgets (inbuf, bufsize, mbox)));
      assert (!(strncmp (inbuf, "X-Coding-System: ", 17)));
      assert ((fgets (inbuf, bufsize, mbox)));
      assert (!(strncmp (inbuf, "Mail-from: ", 11)));
      strcpy (inbuf, inbuf+11);
    }
    fprintf (msg, "%s", inbuf);
  }
  fclose (mbox);
  if (msg)
    fclose (msg);
  exit (0);
}