# The LearningOnline Network
# RSS Feeder
#
# $Id: lonrss.pm,v 1.2 2005/11/18 13:35:30 www Exp $
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
#
# LON-CAPA 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.
#
# LON-CAPA 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 LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# /home/httpd/html/adm/gpl.txt
#
# http://www.lon-capa.org/
#

package Apache::lonrss;

use strict;
use Apache::Constants qw(:common);
use Apache::loncommon;
use Apache::lonnet;
use Apache::lontexconvert;
use Apache::lonlocal;
use Apache::lonhtmlcommon;

my $feedcounter=0;

sub filterfeedname {
    my $filename=shift;
    $filename=~s/\.rss$//;
    $filename=~s/\W//g;
    return $filename;
}

sub feedname {
    return 'nohist_'.&filterfeedname(shift).'_rssfeed';
}

sub displayfeedname {
    my ($rawname,$uname,$udom)=@_;
    my $filterfilename=&filterfeedname($rawname);
# do we have a stored name?
    my %stored=&Apache::lonnet::get('nohist_all_rss_feeds',[$filterfilename],$udom,$uname);
    if ($stored{$filterfilename}) { return $stored{$filterfilename}; }
# no, construct a name
    my $name=$filterfilename; 
    if ($name=~/^CourseBlog/) {
        $name=&mt('Course Blog');
	if ($env{'course.'.$env{'request.course.id'}.'.description'}) {
	    $name.=' '.$env{'course.'.$env{'request.course.id'}.'.description'};
	}
    } else {
	$name=~s/\_/ /g;
    }
    return $name;
}

sub renamefeed {
    my ($rawname,$uname,$udom,$newname)=@_;
    return &Apache::lonnet::put('nohist_all_rss_feeds',
				{ &filterfeedname($rawname) => $newname },
				$udom,$uname);
}

sub advertisefeeds {
    my ($uname,$udom)=@_;
    my $feeds='';
    my %feednames=&Apache::lonnet::dump('nohist_all_rss_feeds',$udom,$uname);
    foreach (sort keys %feednames) {
	if ($_!~/^error\:/) {
	    my $url='feed://'.$ENV{'HTTP_HOST'}.'/public/'.$udom.'/'.$uname.'/'.$_.'.rss';
	    $feeds.='<li><a href="'.$url.'">'.
		$feednames{$_}.'</a><br /><tt>'.$url.'</tt></li>';
	}
    }
    if ($feeds) {
	return '<h4>'.&mt('Available RSS Feeds and Blogs').'</h4><ul>'.$feeds.'</ul>';
    } else {
        return '';
    }
}

sub addentry {
    $feedcounter++;
    my $id=time.'00000'.$$.'00000'.$feedcounter;
    return &editentry($id,@_);
}

sub editentry {
    my ($id,$uname,$udom,$filename,$title,$description,$url,$status,$encurl,$enclength,$enctype)=@_;
    my $feedname=&feedname($filename);
    &Apache::lonnet::put('nohist_all_rss_feeds',
			 { &filterfeedname($filename) => &displayfeedname($filename,$uname,$udom) },
			 $udom,$uname);
    return &Apache::lonnet::put($feedname,{
	$id.'_title' => $title,
	$id.'_description' => $description,
	$id.'_link' => $url,
	$id.'_enclosureurl' => $encurl,
	$id.'_enclosurelength' => $enclength,
	$id.'_enclosuretype' => $enctype,
	$id.'_status' => $status},$udom,$uname);
}

sub changestatus {
    my ($id,$uname,$udom,$filename,$status)=@_;
    my $feedname=&feedname($filename);
    if ($status eq 'deleted') {
	return &Apache::lonnet::del($feedname,[$id.'_title',
					       $id.'_description',
					       $id.'_link',
					       $id.'_enclosureurl',
					       $id.'_enclosurelength',
					       $id.'_enclosuretype',
					       $id.'_status'],$udom,$uname);
    } else {
	return &Apache::lonnet::put($feedname,{$id.'_status' => $status},$udom,$uname);
    }
}

sub handler {
    my $r = shift;
    &Apache::loncommon::content_type($r,'text/xml');
    $r->send_http_header;
    return OK if $r->header_only;

    my (undef,undef,$udom,$uname,$filename)=split(/\//,$r->uri);
    my $filterfeedname=&filterfeedname($filename);
    my $feedname=&feedname($filename);
    my $displayfeedname=&displayfeedname($filename,$uname,$udom);
    $r->print("<rss version='2.0' xmlns:dc='http://purl.org/dc/elements/1.1'>\n<channel>".
	      "\n<link>http://".$ENV{'HTTP_HOST'}.'/</link>'.
	      "\n<description>".&mt('An RSS Feed provided by the LON-CAPA Learning Content Management System').'</description>');
# Is this user for real?
    my $homeserver=&Apache::lonnet::homeserver($uname,$udom); 
    if ($homeserver eq 'no_host') {
	$r->print('<title>'.&mt('No feed available').'</title>');
    } else {
# Course or user?
	my $name='';
	if ($uname=~/^\d/) {
	    my %cenv=&Apache::lonnet::dump('environment',$udom,$uname);
	    $name=$cenv{'description'};
	} else {
	    $name=&Apache::loncommon::nickname($uname,$udom);
	}
        $r->print("\n<title>".&mt('LON-CAPA RSS Feed "[_1]" for [_2]',$displayfeedname,$name).'</title>');
# Render private items?
        my $viewpubliconly=1;
        if (($env{'user.name'} eq $uname) && ($env{'user.domain'} eq $udom)) {
	    $viewpubliconly=0;
	}
# Get feed items
        my %newsfeed=&Apache::lonnet::dump($feedname,$udom,$uname);
	foreach (sort keys %newsfeed) {
	    if ($_=~/^(\d+)\_status$/) {
		my $id=$1;
		if (($newsfeed{$id.'_status'} ne 'public') && ($viewpubliconly)) { next; }
		if ($newsfeed{$id.'_status'} eq 'hidden') { next; }
		$r->print("\n<item>\n<title>".$newsfeed{$id.'_title'}."</title>\n<description>".
			  $newsfeed{$id.'_description'}."</description>\n<link>".
			  $newsfeed{$id.'_link'}."</link>\n");
		if ($newsfeed{$id.'_enclosureurl'}) {
		    $r->print("\n<enclosure url='".$newsfeed{$id.'_enclosureurl'}."' length='".$newsfeed{$id.'_enclosurelength'}.
			      "' type='".$newsfeed{$id.'_enclosuretype'}."' />");
		}
		$r->print("\n<guid>".$id.$filterfeedname.'_'.$udom.'_'.$uname."</guid></item>\n");
	    }
	}
    }
    $r->print("\n</channel></rss>\n");
    return OK;
} 

1;
__END__