# A simple interface to www.scholix.org
# Takes a PID, eg a DOI, passes this to the scholix API for a list of related online resources
# Renders the results as an HTML list
# Designed for easy inclusion in other pages via an ajax call
#
# Written by: Justin Bradley, EPrints Servies, April 2020
# Updated by: David Newman, EPrints Services, February 2021

use EPrints;
use JSON;
use LWP::UserAgent;
use strict;

my $session = EPrints::Session->new();
$session->send_http_header( content_type => "text/html; charset=iso-8859-1" );

my $pid = $session->param( "pid" ); # eg 10.1016/j.quascirev.2019.106103
$pid =~ s/[ ";\\]+//g;

my $url = "http://api.scholexplorer.openaire.eu/v1/linksFromPid?pid=$pid";
my $ua = LWP::UserAgent->new;
my $response = $ua->get( $url, "accept", "application/json" );
if ( $response->code ne "200" )
{
  $session->terminate();
  exit;
}
my $json = decode_json( $response->content );

if( !$json || ref($json) ne 'ARRAY' )
{
  $session->terminate();
  exit;
}

my %seen;
my $done_title = 0;
# print "<div style='border: 1px solid #cccccc; box-shadow: 0 2px 6px rgba(100, 100, 100, 0.3); padding-right: 20px; width: 500px;'>\n<ul>\n";

foreach my $s ( @$json )
{
  my $title = $s->{target}->{title};
  my $i = $s->{target}->{identifiers}[0];
  my $ident = $i->{identifier};
  my $scheme = $i->{schema};

  # next unless $ident =~ /10\.1594/; # limit to pangea resources

  print "<div style='font-weight: bold;'>Related Data</div>\n" unless $done_title;
  $done_title = 1;

print <<EOT unless $seen{ $ident };
  <li style="padding-bottom: 10px; list-style: none; font-size: 90%;">
    <span>$title</span><br/>
    <a href="$ident">$ident</a>
  </li>
EOT
  $seen{ $ident } = 1;
}
#print "</ul>\n</div>\n";

$session->terminate();