#!/usr/bin/perl
   use strict;
   use warnings;

   use Tie::Handle::CSV;
   use Data::Dumper;

   our $foundZero = 0;
   my $currentPO = '';
   my $countCurrentPO = 0;
   my $debug = 1;
   my @amounts;
   my $fh = Tie::Handle::CSV->new('test2.csv', header => 1);

   open MATCHES, ">matches.csv";
   open VARIANCES, ">variances.csv";

   my @lines = <$fh>;
   undef my @matchedLines;
   print "FINDING MATCHES...\n";
   for (my $k = 0; $k < $#lines + 1; $k++) {
      $countCurrentPO++;
      print "k: " . $k . "\n" if $debug;
      my $csv_line = $lines[$k];
      my $debit  = ($csv_line->{'DEBIT_AMOUNT'}  eq '') ? 0 : $csv_line->{'DEBIT_AMOUNT'};
      my $credit = ($csv_line->{'CREDIT_AMOUNT'} eq '') ? 0 : $csv_line->{'CREDIT_AMOUNT'};
      my $po = $csv_line->{'PO_NUM'};
      my $total = $credit - $debit;

      # print "matchedLines[k]: ". $matchedLines[$k - 1] . "\n" if defined($matchedLines[$k - 1]);

      if (!(defined($matchedLines[$k]))) { # if the current line haven't been matched previously

         if (@amounts < 1) {$currentPO = $po} # if it's the first one, it becomes the current PO
            print "PO/CURRENTPO: " . $po . "/" . $currentPO . " countCurrentPO: " . $countCurrentPO . "\n" if $debug;
            if ((($po eq $currentPO) || ($k == 0))) {
               # dont add a duplicate amount (with same row number)
  #             my $temp = defined($amounts[0][1]) ? $amounts[0][1] : 6666666; # will never get 6666666 rows, so it should be safe..
               push(@amounts, [$total, $k]);# if ($temp != $k);
              if ($k == 77) {
                 my $d = Data::Dumper->new(\@amounts);
                 print $d->Dump;
              }
               if ($k == $#lines) {
                 print "TOTAL1: " . $total . " I3: " . $k . "\n" if $debug;
                  my $output = allSums_f2(\@amounts);
                 print "OUTPUT3: " . $output . "\n" if $debug;
                  my @numbers = split(/ /, $output);
                  if ($foundZero == 1) {
                     foreach(@numbers) {
                        $matchedLines[$_] = 1;
                        print "(1) SETTING NUMBER $_ AS MATCHED\n" if $debug;
                     }
                     $foundZero = 0;
                    # $k = $k - $countCurrentPO;
                    # $countCurrentPO = 0;
                  }
               }
            } else { # this amount is part of a new PO, process old ones
                print "TOTAL2: " . $total . " I3: " . $k . "\n" if $debug;
  #            if ($k == 77) {
  #                my $d = Data::Dumper->new(\@amounts);
  #                print $d->Dump;
  #            }
                 my $output = allSums_f2(\@amounts);
                 print "OUTPUT4: $output \n" if $debug;
                 my @numbers = split(/ /, $output);
                 my $tempK = $k;

                 if ($foundZero == 1) {
                    foreach(@numbers) {
                       $matchedLines[$_] = 1;
		       print "(2) matchedLines[_]: ". $matchedLines[$_] . "\n" if (( $matchedLines[$_] == 1) && $debug);
                       print "(2) SETTING NUMBER $_ AS MATCHED\n" if $debug;
                    }
                    $foundZero = 0;

                    $k = $k - $countCurrentPO;
                    print "tempK: " . $tempK . " K: " .$k . "\n" if $debug;
                    @amounts = ();
                    print "TOTAL: $total\n" if $debug;
                    push(@amounts, [$total, $tempK]);
                    $countCurrentPO = 1;
                #    $currentPO = $po;
                 }
                 else {
                    @amounts = ();
                    push(@amounts, [$total, $k]);
                    $countCurrentPO = 1;
                    $currentPO = $po;
                 }
       #         print "DUMP1:    ";
       #         my $d = Data::Dumper->new(\@amounts);
       #         print $d->Dump;
            }
      }
   }

   print "WRITING RESULT FILES...\n";
   for (my $j = 0; $j < $#matchedLines + 1; $j++) {
       if (defined($matchedLines[$j])) {
          print MATCHES $lines[$j] . "\n";
       } else {
          print VARIANCES $lines[$j] . "\n";
       }
   }

   close $fh;


   sub allSums_f2 {
      my($check_ref) = @_;
      my @check = @{$check_ref};
      my $desired = 0;

   #   foreach my $index (0..2**@check-1) {
      for (my $index = 0; $index <= 2**@check-1; $index++) {
         my $sum = 0;
         foreach my $pos (0..@check-1) {
            my $bit = ($index >> $pos) % 2;
   #               my $d = Data::Dumper->new(\@check);
   #               print $d->Dump;
            $sum += $bit * $check[$pos][0];
         }
         if ($sum == $desired) {
            my @combo;
            foreach my $pos (0..@check-1) {
               push @combo, $check[$pos][1] if  ($index >> $pos) % 2;
            }
            if (@combo > 0) {
               print join " ", @combo, "\n";
               $foundZero = 1;
               return join(' ',@combo)
            }
         }
      }
   }