#!/usr/bin/perl

use warnings;
use strict;

use IO::File;
use File::Find;

# <a href="http://validator.w3.org/check?uri=referer">
# <img src="http://www.w3.org/Icons/valid-html401"
#      alt="Valid HTML 4.01 Transitional"
#      height="31" width="88"></a>

find(\&fix_if_file,@ARGV);

sub fix_if_file {
    return unless -f $_;
    my $fh = IO::File->new($_,'r') or
        die "Unable to open $_ for reading: $!";
    local $/;
    my $fc = <$fh>;
    close($fh);
    # strip out the w3c img callback; replace with alt text
    my $changed = $fc =~ s{<img\s+src="http://www.w3c?.org/Icons/[^"]+"[^>]*?alt="([^"]+)"[^>]*>}{$1}imsg;
    # if it doesn't have alt text, just replace it with Valid HTML
    $changed += $fc =~ s{<img\s+src="http://www.w3c?.org/Icons/[^"]+"[^>]*>}{Valid HTML}imsg;

    if ($changed) {
        $fh = IO::File->new($_,'w') or
            die "Unable to open $_ for writing: $!";
        print {$fh} $fc;
        close($fh);
        print STDERR "$File::Find::name was changed\n";
    }
}