#! /usr/bin/perl

# zeitungen-rdf - Build RDF file for www.zeitungsliste.de
# Copyright (c) 2008  Joey Schulze <joey@infodrom.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.

use strict;
use warnings;

use DBI;
use XML::RSS;
use Algorithm::Diff;

my %cfg = ('home' => 'http://www.zeitungsliste.de/',
	   'webdir' => '/var/www/www.zeitungsliste.de');

my $dsn = 'dbi:Pg:dbname=zlist';

my $dbh = DBI->connect('dbi:Pg:dbname=zlist') or die "Can't connect to database\n";

sub fetchnew
{
    my $query = q{SELECT id,name,description FROM zeitungen
		  WHERE deleted IS false AND changed > now() - interval'3 months'
		  ORDER BY changed DESC};

    my $sth = $dbh->prepare ($query) or die "Can't prepare Query: $DBI::errstr\n";
    my $rv = $sth->execute or die "Can't execute query: $DBI::errstr\n";

    my @ret = ();
    push @ret, [$_->{id},$_->{name},$_->{description}] while ($_ = $sth->fetchrow_hashref);

    return \@ret;
}

sub rdf_new
{
    my $fname = shift;
    my $papers = fetchnew();

    my $rss = new XML::RSS (version => '1.0', encoding => 'utf-8');
    $rss->channel (
	title          => 'Zeitungsliste',
	description    => 'Zeitungen im Netz',
	link           => $cfg{'home'},
	);

    foreach my $paper (@$papers) {
	# printf "%d: %s\n%s\n", $paper->[0], $paper->[1], $paper->[2];

	$rss->add_item (
	    title       => $paper->[1],
	    description => $paper->[2],
	    link        => sprintf('%szeitung/%d.html', $cfg{'home'}, $paper->[0]),
	    );
    }

    if (-e $fname) {
	my @new = split (/\n/, $rss->as_string);
	open (F, $fname);
	chomp(my @old = <F>);
	close (F);

	my @diff = Algorithm::Diff::diff (\@old, \@new);
	$rss->save ($fname) if (@diff);
    } else {
	$rss->save ($fname);
    }
}

rdf_new($cfg{webdir} . '/zeitungen.rdf');