# ResolveURLs.pl 
#
# by Alexei Kosut <akosut@cs.stanford.edu>
# Last modified February 3, 2003 (1.0.2)
#
# Add global filter tag resolve_urls to expand relative URLs
# in href and src attributes of HTML tags.  They are always expanded
# directly relative to the site URL of the weblog.

use strict;

use MT::Template::Context;
use URI;

sub resolve_uri($$) {
    my ($uri, $siteurl) = @_;
    return $uri if ($uri =~ /^\#/);	# Do not resolve URI fragments
    return URI->new_abs($uri, $siteurl);
}

MT::Template::Context->add_global_filter(resolve_urls => sub {
    my ($s, $arg, $ctx) = @_;
    my $blog = $ctx->stash('blog')
	or return $ctx->error("Tag called without a blog in context");
    my $siteurl = $blog->site_url;

    $siteurl .= "/" if (substr($siteurl, -1) ne "/");

    # Find each URL and make it absolute
    $s =~ s{(<[^>]*\s(?:href|src)=)(?:\"([^\">]+)\"|'([^\'>]+)'|([a-zA-Z0-9._-]+))(/?>|\s)}
           {$1 . '"' . resolve_uri($2 || $3 || $4, $siteurl) . '"' . $5}gei;

    return $s;
});