#!/usr/bin/perl
use warnings;
use strict;
use autodie;
use LWP::Simple;
use CGI;
use Data::Dump qw(dump);

my $q = CGI->new;
my $feed = $q->param('feed') || 'polemos';

print qq|Content-type: application/rss+xml\r\n\r\n|;

my $feed_file = $feed;
$feed_file =~ s/\W+/_/g;
$feed_file = "cache/$feed_file.rss";

if (mirror("https://hrcak.srce.hr/en/rss/$feed", $feed_file) == RC_NOT_MODIFIED) {
	warn "Modified $feed into rss/$feed_file\n";
}

my $bottom;
my @parts;
{ 
	open(my $fh, '<', $feed_file);
	local $/ = undef;
	my $rss = <$fh>;
	my $top = $1 if $rss =~ s/^(.*?)<item>//is;
	print $top;
	$bottom = $1 if $rss =~ s/(<\/channel>.*)$//is;
	@parts = split(/<item>/i, $rss);
}

my $month2nr;
{
	my @months = qw(
January
February
March
April
May
June
July
August
September
October
November
December
	);

	my $m = 1;
	foreach ( @months ) {
		$month2nr->{$_} = sprintf("%02d", $m++);
	}
}


sub month_year {
	my $item = shift;
	if ( $item =~ m/Published: (\w+) (\d{4})\./ ) {
		return $2 . $month2nr->{$1};
	} else {
		die "no Published: in [$item]";
	}
}

my @sorted = sort { month_year($a) cmp month_year($b) } @parts;

foreach ( @sorted ) {
	s/<title>.*Vol/<title>Vol/gs;
	print "<item>", $_;
}

print $bottom;