#!/usr/bin/perl

# Usage: chompie.pl run_script orig_program dest_program
#
# run_script is passed the name of the program to run. It can then filter the
# results as appropriate.

use strict;
use File::Slurp;
use POSIX qw(ceil);

my ($run_filename, $src_filename, $dest_filename) = @ARGV;

my @src = read_file($src_filename);

write_file($dest_filename, @src);

my $target = `$run_filename "$dest_filename" 2>&1`;

print "BEGIN_TARGET\n$target\nEND_TARGET\n";

my $num_lines = $#src;
print "src rows: $num_lines\n";

# test the file
sub test_file {
  my ($run_filename, $dest_filename, $target, @cur_src) = @_;
  write_file($dest_filename, @cur_src);
  print ".";
  my $result = `$run_filename "$dest_filename" 2>&1`;
  return ($target eq $result);
}


# Single Line Chopping

my $current_lines;

do {

  $current_lines = scalar @src;

  KILLEH: for my $width (1..(scalar @src)) {
    for(my $i = 0; $i < $current_lines; $i++) {
      my (@chopped_src) = @src;
      splice @chopped_src, $i, $width;
      if(test_file($run_filename, $dest_filename, $target, @chopped_src)) {
        print "\nChopped $width lines at $i\n";
        @src = @chopped_src;
        last KILLEH;
      }
    }
  }

} until($current_lines == (scalar @src));

write_file($dest_filename, @src);

print "\nDone! Eliminated " . ($num_lines - @src) . " lines!\n";





=pod

# Binary Tree Chopping
my $depth = 1;

while($num_lines / (2**$depth) >= 1) {
  my $chunk_size = int ($num_lines / (2**$depth));
  my $chunk_count = ceil($num_lines / $chunk_size);
  print "Depth: $depth\tchunk_size: $chunk_size\tchunk_count: $chunk_count\n";
  foreach my $bitmask (1 .. ((2**$chunk_count)-2)) {
    my @cur_src;
    foreach my $line_num (0 .. $num_lines) {
      my $chunk_num = int ($line_num / $chunk_size);
      if($bitmask & (2**$chunk_num)) {
        push @cur_src, $src[$line_num];
      }
    }
    printf "----($chunk_size | $bitmask (%b))----\n".(join'',@cur_src), $bitmask;
    # test the file
    # if it passes, use @cur_src as @src and go to zero depth
    if(test_file($run_filename, $dest_filename, $target, @cur_src)) {
      print "Keeping new version!\n";
      $depth = 0;
      @src = @cur_src;
      $num_lines = $#src;
      last;
    }
  }
  $depth++;
}

=cut