#!/usr/bin/perl
#
use Algorithm::Diff qw(diff);
my $file1 = '/file1.txt';
my $file2 = '/file2.txt';

-T $file1 or bag("$file1: binary");
-T $file2 or bag("$file2: binary");

open (F1, $file1) or bag("Couldn't open $file1: $!");
open (F2, $file2) or bag("Couldn't open $file2: $!");

chomp(@f1 = <F1>);
close F1;
chomp(@f2 = <F2>);
close F2;

$diffs = diff(\@f1, \@f2);
exit 0 unless @$diffs;

my @f11;
my $lineno = 0;
foreach (@f1) {
    push @f11, [' ', $lineno, $_];
    $lineno++;
}

my @f22;
$lineno = 0;
foreach (@f2) {
    push @f22, [' ', $lineno, $_];
    $lineno++;
}

foreach $chunk (@$diffs) {
  foreach $line (@$chunk) {
    my $i = 0;
    my ($sign, $lineno, $text) = @$line;
    foreach (@f11) {
        if ($_->[1] eq $lineno) {
            if ($sign eq '+') {
                splice @f11, $i, 0, ['+', $lineno, ' '];
                splice @f11, $i, 1, ['+', $lineno, $text];
                last;
            } elsif ($sign eq '-') {
                splice @f11, $i, 1, ['-', $lineno, $text];
                last;
            }
        }
        $i++
    }
  }
}

my $cnt = 1;
foreach (@f11) {
    print "$cnt: $_->[2]\n";
    $cnt++;
    
}