package EPrints::Plugin::Export::JSONLD;

use EPrints::Plugin::Export;

@ISA = ( "EPrints::Plugin::Export" );

use strict;

use JSON;

sub new

{

my( $class, %params ) = @_;

my $self = $class->SUPER::new( %params );

$self->{name} = "JSON LD";

$self->{accept} = [ 'dataobj/eprint', 'list/eprint' ];

$self->{visible} = "all";

$self->{suffix} = ".js";

$self->{mimetype} = "application/json; charset=utf-8";

return $self;

}

sub output_list

{

my( $self, %opts ) = @_;

my $r = [];

my $part;

$part = "{\"\@context\": \"http://schema.org\",\"\@graph\": [\n";

if( defined $opts{fh} )

{

print {$opts{fh}} $part;

}

else

{

push @{$r}, $part;

}

$opts{json_indent} = 1;

my $first = 1;

$opts{list}->map( sub {

my( $session, $dataset, $dataobj ) = @_;

my $part = "";

if( $first ) { $first = 0; } else { $part = ",\n"; }

$part .= $self->output_dataobj( $dataobj);

if( defined $opts{fh} )

{

print {$opts{fh}} $part;

}

else

{

push @{$r}, $part;

}

} );

$part= "\n]}\n\n";

if( defined $opts{fh} )

{

print {$opts{fh}} $part;

}

else

{

push @{$r}, $part;

}

if( defined $opts{fh} )

{

return;

}

return join( '', @{$r} );

}

sub dataobj_to_html_header

{

my( $plugin, $dataobj ) = @_;

my $jsonld = $plugin->{session}->make_doc_fragment;

my $script_tag = $plugin->{session}->make_element( "script", type => "application/ld+json", id => "jsonLinkedData" );

my $eprintld = $plugin->convert_dataobj( $dataobj );

my $json = JSON::to_json( $eprintld );

$script_tag->appendChild( $plugin->{session}->make_text( $json ) );

$jsonld->appendChild($script_tag);

$jsonld->appendChild( $plugin->{session}->make_text( "\n" ) );

return $jsonld;

}

sub convert_dataobj

{

my( $plugin, $eprint ) = @_;

my $dataset = $eprint->{dataset};

my %jsonldata;

$jsonldata{'@context'} = 'http://schema.org/';

$jsonldata{'@type'} = "CreativeWork";

if ( $eprint->exists_and_set( "type" )){

if ($eprint->get_value( "type" ) eq "thesis" ){

$jsonldata{'@type'} = "Thesis";

}

elsif ($eprint->get_value( "type" ) eq "dataset" ){

$jsonldata{'@type'} = "Dataset";

}

elsif ( $eprint->get_value( "type" ) eq "article" ){

$jsonldata{'@type'} = "ScholarlyArticle";

}

elsif ( $eprint->get_value( "type" ) eq "book_section" ){

$jsonldata{'@type'} = "Chapter";

}

elsif ( $eprint->get_value( "type" ) eq "book" ){

$jsonldata{'@type'} = "Book";

}

}

# The DOI or if not set, URL of the landing page

if ( $eprint->exists_and_set( "doi" ) ) {

$jsonldata{url} = 'https://doi.org/' . $eprint->get_value( "doi" );

$jsonldata{'@id'} = 'https://doi.org/' . $eprint->get_value( "doi" );

$jsonldata{sameAs} = $eprint->get_url();

} elsif ( $eprint->exists_and_set( "eprintid" ) ) {

$jsonldata{url} = $eprint->get_url();

}

# The title of the dataset

if( $eprint->exists_and_set( "title" ) ) {

$jsonldata{name} = $eprint->get_value( "title" );

}

# Prefer the lay summary for Google, if there is one, otherwise the abstract will do

if( $eprint->exists_and_set( "lay_summary" ) ) {

$jsonldata{description} = $eprint->get_value( "lay_summary" );

} elsif( $eprint->exists_and_set( "abstract" ) ) {

$jsonldata{description} = $eprint->get_value( "abstract" );

}

# Include version number

if( $eprint->exists_and_set( "version" ) ) {

$jsonldata{version} = $eprint->get_value( "version" );

}

# Add keywords and subjects as keywords

my @keywords;

if ( $eprint->exists_and_set( "keywords" ) ) {

my $keywords = $eprint->get_value( "keywords" );

push @keywords, split( ",", $keywords );

}

if( $eprint->exists_and_set( "subjects" ) ) {

foreach my $subjectid ( @{$eprint->get_value( "subjects" )} )

{

my $subject = EPrints::DataObj::Subject->new( $plugin->{session}, $subjectid );

next unless( defined $subject );

push @keywords, EPrints::Utils::tree_to_utf8( $subject->render_description() );

}

}

$jsonldata{keywords} = join ( ", ", @keywords ) if scalar @keywords > 0;

if( $eprint->exists_and_set( "creators" ) )

{

my $creators = $eprint->get_value( "creators" );

if( defined $creators )

{

foreach my $creator ( @{$creators} )

{

my %person;

$person{'@type'} = "Person";

$person{'@id'} = 'http://orcid.org/' . $creator->{orcid} if (defined ($creator->{orcid}) && $creator->{orcid} ne '');

my $name = $creator->{name};

$person{familyName} = $name->{family} if defined $name->{family};

$person{givenName} = $name->{given} if defined $name->{given};

push @{$jsonldata{creator}}, \%person;

}

}

}

if ( $eprint->exists_and_set( "corp_creators" ) ) {

my $corp_creators = $eprint->get_value( "corp_creators" );

if( defined $corp_creators )

{

foreach my $corp_creator ( @{$corp_creators} )

{

my %corp;

$corp{'@type'} = "Organization";

$corp{name} = $corp_creator;

push @{$jsonldata{creator}}, \%corp;

}

}

}

if( $eprint->exists_and_set( "date" ) ) {

my @date = split( "-", $eprint->get_value( "date" ) );

$jsonldata{datePublished} = $date[0];

}

if ( $eprint->exists_and_set( "publisher" ) ) {

my %publisher;

$publisher{'@type'} = "Organization";

$publisher{name} = $eprint->get_value( "publisher" );

$jsonldata{publisher} = \%publisher;

}

return \%jsonldata;

}

sub output_dataobj_html

{

my( $plugin, $dataobj ) = @_;

my $json = $plugin->convert_dataobj( $dataobj );

return $plugin->dataobj_to_html_header( $dataobj );

}

sub output_dataobj

{

my( $plugin, $dataobj ) = @_;

my $eprintld = $plugin->convert_dataobj( $dataobj );

my $json = JSON::to_json( $eprintld );

return $json;

}

1;