#!/usr/bin/perl -w
use strict;
use constant DEPTH=>9;
use constant ENDCHANCE=>0.5;
use constant MINLENGTH=>20;
use constant MAXLENGTH=>200;
# change the depth to change the quality of the output, higher values
# are more faithful to the input text. Endchance determines the probability
# that the output will stop at a period. You can change your input file
# as desired below. Minlength prevents end of output before sending that many
# characters. Maxlength forces end of output at next period after that many
# characters.
open FILE, "/usr/share/games/fortune/wisdom" || die "Find your fortune file!\n";
my $text="";
print "\n\nHail, O Aspirant! I am the almighty Oracle. I don't have time for\n";
print "pleasantries, so just type the topic of your consultation in one\n";
print qq~or two words.\n\n--O Oracle, tell me about: ~;
while (<FILE>) {
  if ((!/--/)&&(!/^%/)) {
# This is specifically for fortune files, which have -- before citations
# and % separating lines. Change as necessary for your input.
    chomp;
    $text.="$_ ";
  }
}
my $start=<STDIN>;
chomp($start);
if (index($text,$start)<0) {
   my $position=int rand (length($text)/2);
   $position=index($text," ",$position);
   $start=substr($text,$position+1,DEPTH);
}
if (length($start)<DEPTH) {
  my $pos= index($text,$start);
  $start=substr($text,$pos,DEPTH);
} else { 
  
  $start=substr($start,0,DEPTH);
}
my $length=DEPTH;
my $newchar='~';
print "\n\nThe Oracle speaks: \n\n";
print ucfirst($start);
while (($newchar ne ".") || ($length<MINLENGTH) || (($length<=MAXLENGTH) && (rand()<ENDCHANCE))) { 
  $newchar = &get_another_char($start);
  $start= substr($start,1) . $newchar;
  print $newchar;
  $length++;
}
print "\n\n";
undef $text;


sub get_another_char {
  my $pattern=shift;
  my $offset=int(rand length($text));
  my $spot=0;
  my $cha;
  $spot=index($text,$pattern,$offset);
  $spot=index($text,$pattern) if $spot==-1;
  die "Oops: $pattern\n\n" if $spot==-1;
  $cha=substr($text,$spot+DEPTH,1);
  return $cha;
}