######################################################################
#
#  Paracitation Module
#
######################################################################
#
#  This file is part of GNU EPrints 2.
#  
#  Copyright (c) 2000-2004 University of Southampton, UK. SO17 1BJ.
#  
#  EPrints 2 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.
#  
#  EPrints 2 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 EPrints 2; if not, write to the Free Software
#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
######################################################################

use EPrints;
use ParaTools::CiteParser::Standard;
use URI;

use strict;
my $session = new EPrints::Session;
exit( 0 ) unless( defined $session );

my $ds = $session->get_repository->get_dataset( "archive" );

&process( $session );

$session->terminate;

exit;


sub process
{
	my( $session ) = @_;
	
	my $title = $session->html_phrase( "cgi/paracite:title" );

	unless( EPrints::Utils::is_set( $session->param("ref") ) )
	{
		$session->build_page( 
			$title, 
			$session->html_phrase( "cgi/paracite:no_reference" ),
			"paracite" );
		$session->send_page();
		return;
	}


	my $ref = $session->param("ref");

	my $parser = new ParaTools::CiteParser::Standard();
	my $metadata = $parser->parse($ref);
	my ($year, $author) = ($metadata->{year}, $metadata->{aulast});

	if (!defined $year || $year eq "") 
	{
		$_ = $ref;
		/\b(\d{4})\b/;
		$year = $1;
		if ($year !~ /^\d{4}/) { $year = ""; }
	}
	if (!defined $author || $author eq "")
	{
		$ref =~ m/^([a-zA-Z]+)/;
		$author = $1;
	}

       	my $url = $ref;
	my $uri = URI->new( $url );
       	$url =  $uri->as_string;
	$url =~ s/&/%26/g;
	my $paraurl = 'http://paracite.eprints.org/cgi-bin/paracite.cgi?ref='.$url;

	unless( EPrints::Utils::is_set( $author ) )
	{
		$session->redirect( $paraurl );
		return;
	}

	my $searchexp = new EPrints::Search(
		filters => [
			{ meta_fields=>[ 'metadata_visibility' ], value=>'show', match=>'EQ', merge=>"ANY", describe=>0 },
		],
		session => $session,
		dataset => $ds );

	if( EPrints::Utils::is_set( $author ) )
	{
		if( $ds->has_field( "authors" ) )
		{
			$searchexp->add_field( $ds->get_field( "authors" ), $author );
		}
		elsif( $ds->has_field( "creators" ) )
		{
			$searchexp->add_field( $ds->get_field( "creators" ), $author );
		}
		# otherwise dunno what to do.
	}

	if( EPrints::Utils::is_set( $year ) )
	{
		if( $ds->has_field( "year" ) )
		{
			$searchexp->add_field( $ds->get_field( "year" ), $year );
		}
		elsif( $ds->has_field( "date" ) )
		{
			$searchexp->add_field( $ds->get_field( "date" ), $year );
		}
		# otherwise dunno what to do
	}

	$searchexp->perform_search();
	my $count = $searchexp->count();
	if( $count == 0 )
	{
		$session->redirect( $paraurl );
		$searchexp->dispose;
		return;
	}

	my $page = $session->make_doc_fragment();
	my $p = $session->make_element( "p" );
	$p->appendChild( $session->make_text( $ref ) );
	$page->appendChild( $p );
	my @matches = $searchexp->get_records( 0, 10 );
	$page->appendChild( $session->html_phrase( "cgi/paracite:possible_matches" ) );
	foreach my $m ( @matches )
	{
		my $p = $session->make_element( "p" );
		$p->appendChild( $m->render_citation_link );
		$page->appendChild( $p );
	}
	$page->appendChild( $session->render_ruler );
	my $a = $session->make_element( "a", href=>$paraurl );
	$page->appendChild( $session->html_phrase( 
		"cgi/paracite:paracite_link",
		link=>$a ));

	$session->build_page( $title, $page, "paracite" );
	$session->send_page();
	return;
}