package Catmandu::Importer::Wikidata;
#ABSTRACT: Import from Wikidata
our $VERSION = '0.3.0'; #VERSION
use Catmandu::Sane;
use Moo;
use URI::Template;

extends 'Catmandu::Importer::getJSON';

has api => ( 
    is => 'ro', 
    default => sub { 'http://www.wikidata.org/w/api.php' } 
);

has '+url' => (
    is => 'ro',
    lazy => 1,
    builder => sub { 
        URI::Template->new(
            $_[0]->api 
            . '?action=wbgetentities&format=json{&ids}{&sites}{&titles}'
        );
    }
); 

has '+from' => ( 
    is => 'ro', 
    lazy => 1,
    builder => \&_build_from,
);

has ids => (
    is  => 'ro',
    coerce => sub { [ split /[,| ]/, $_[0] ] }
);

has site => (
    is => 'ro',
    default => sub { 'enwiki' },
    trigger => sub {
        my ($self,$site) = @_;
        die "invalid site $site" if $site !~ /^[a-z]+([_-][a-z])*$/;
        $site =~ s/-/_/g;
        return $site;
    }
);

has title => (
    is => 'ro',
);

sub _build_from {
    my ($self) = @_;

    my $vars;

    if ($self->ids) {
        my @ids = map {
            $_ =~ /^[QP][0-9]+$/i or die "invalid wikidata id $_\n";
            uc($_);
        } @{$self->ids};
        $vars = { ids => join('|', @ids) };
    } elsif(defined $self->title) {
        my ($site, $title);
        if ($self->title =~ /^([a-z]+([_-][a-z])*):(.+)$/) {
            ($site, $title) = ($1,$3);
        } else {
            ($site, $title) = ($self->site,$self->title);
        }
        die "invalid site $site" if $site !~ /^[a-z]+([_-][a-z])*$/;
        $site =~ s/-/_/g;
        # TODO: pass multiple sites|titles
        $vars = { sites => $site, titles => $title };
    }

    return ($vars ? $self->url->process($vars) : undef);
}

sub request_hook {
    my ($self, $line) = @_;

    if ($line =~ /^[PQ][0-9]+$/i) {
        return { ids => uc($line) };
    } elsif ($line =~ /^([a-z]+([_-][a-z])*):(.+)$/) {
        my ($site, $title) = ($1,$3);
        $site =~ s/-/_/g;
        return { sites => $site, titles => $title };
    } else {
        return { sites => $self->site, titles => $line };
    }

    return;
}

sub response_hook {
    my ($self, $data) = @_;
    # TODO: better error handling
    return [ values %{$data->{entities}} ];
}

1;

__END__

=pod

=encoding UTF-8

=head1 NAME

Catmandu::Importer::Wikidata - Import from Wikidata

=head1 VERSION

version 0.3.0

=head1 SYNOPSIS

    catmandu convert Wikidata --ids Q1,P227
    catmandu convert Wikidata --site dewiki --title Wahnsinn

    echo Q7 | catmandu convert Wikidata
    echo Wahnsinn | catmandu convert Wikidata --site dewiki
    echo dewiki:Wahnsinn | catmandu convert Wikidata

=head1 DESCRIPTION

This L<Catmandu::Importer> queries Wikidata for entities, given by their
Wikidata identifier (C<Q...>, C<P...>) or by a title in some know Wikidata
site, such as the English Wikipedia (C<enwiki>).

See L<Catmandu::Wikidata> for a synopsis.

By default, the raw JSON structure of each Wikidata entity is returned one by
one. Future versions of this module may further expand the entity data to make
more easily use of it.

=head1 CONFIGURATION

This importer extends L<Catmandu::Importer::getJSON>, so it can be configured
with options C<agent>, C<timeout>, C<headers>, C<proxy>, and C<dry>.

=over

=item api

Wikidata API base URL. Default is C<http://www.wikidata.org/w/api.php>.

=item ids

A list of Wikidata entitiy/property ids, such as C<Q42> and C<P19>. Use
comma, vertical bar, or space as separator. Read from input stream if no
ids, nor titles are specified.

=item site

Wiki site key for referring to Wikidata entities by title. Default is
C<enwiki> for English Wikipedia. A list of supported site keys can be
queried as part of
L<https://www.wikidata.org/w/api.php?action=paraminfo&modules=wbgetentities>
(unless L<https://bugzilla.wikimedia.org/show_bug.cgi?id=58200> is fixed).

=item title

Title of a page for referring to Wikidata entities. A title is only unique
within a selected C<site>. One can also prepend the site key to a title
separated by colon, e.g. C<enwiki:anarchy> for the entity that is titled
"anarchy" in the English Wikipedia. Read from input stream if no titles, nor
ids are specified.

=back

=head1 AUTHOR

Jakob Voß

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2013 by Jakob Voß.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=cut
