NAME
    Wikidata::Reconcilation - Abstract class for Wikidata reconcilations.

SYNOPSIS
     use Wikidata::Reconcilation;

     my $obj = Wikidata::Reconcilation->new;
     my @qids = $obj->reconcile($reconcilation_rules_hr);

DESCRIPTION
    Abstract class for Wikidata reconcilation. Method, which need to
    implement: "_reconcile()".

METHODS
  "new"
     my $obj = Wikidata::Reconcilation->new;

    Constructor.

    Returns instance of object.

  "reconcile"
     my @qids = $obj->reconcile($reconcilation_rules_hr);

    Reconcile information defined in input structure and returns list of
    QIDs.

    Returns list of strings.

ERRORS
     new():
             From Class::Utils::set_params():
                     Unknown parameter '%s'.
             Parameter 'lwp_user_agent' must be a 'LWP::UserAgent' instance.

     reconcile():
             This is abstract class. You need to implement _reconcile() method.

EXAMPLE
     use strict;
     use warnings;

     package Foo;

     use base qw(Wikidata::Reconcilation);

     use WQS::SPARQL;
     use WQS::SPARQL::Query::Select;

     sub _reconcile {
             my ($self, $reconcilation_rules_hr) = @_;
 
             # Reconcilation process.
             my @sparql;
             if (exists $reconcilation_rules_hr->{'identifiers'}->{'given_name_qids'}
                     && exists $reconcilation_rules_hr->{'identifiers'}->{'surname_qid'}) {

                     my $sparql = <<'END';
     SELECT ?item WHERE {
       ?item wdt:P31 wd:Q5.
     END
                     foreach my $given_name_qid (@{$reconcilation_rules_hr->{'identifiers'}->{'given_name_qids'}}) {
                             $sparql .= '  ?item wdt:P735 wd:'.$given_name_qid.".\n";
                     }
                     $sparql .= '  ?item wdt:P734 wd:'.
                             $reconcilation_rules_hr->{'identifiers'}->{'surname_qid'}.".\n";
                     $sparql .= "}\n";
                     push @sparql, $sparql;
             } elsif (exists $reconcilation_rules_hr->{'identifiers'}->{'surname_qid'}) {
                     push @sparql, WQS::SPARQL::Query::Select->new->select_value({
                             'P31' => 'Q5',
                             'P734' => $reconcilation_rules_hr->{'identifiers'}->{'surname_qid'},
                     });
             }

             return @sparql;
     }

     package main;

     # Object.
     my $obj = Foo->new('verbose' => 1);

     # Save cached value.
     my @qids = $obj->reconcile({
             'identifiers' => {
                      'given_name_qids' => ['Q18563993', 'Q15730712'], # 'Michal', 'Josef'
                      'surname_qid' => 'Q16883641', # 'Špaček'
             },
     });

     # Output is defined by 'verbose' => 1

     # Output like:
     # SPARQL queries:
     # SELECT ?item WHERE {
     #   ?item wdt:P31 wd:Q5.
     #   ?item wdt:P735 wd:Q18563993.
     #   ?item wdt:P735 wd:Q15730712.
     #   ?item wdt:P734 wd:Q16883641.
     # }
     # 
     # {
     #     head      {
     #         vars   [
     #             [0] "item"
     #         ]
     #     },
     #     results   {
     #         bindings   [
     #             [0] {
     #                     item   {
     #                         type    "uri",
     #                         value   "http://www.wikidata.org/entity/Q27954834"
     #                     }
     #                 }
     #         ]
     #     }
     # }
     # Results:
     # - Q27954834: 1

DEPENDENCIES
    Class::Utils, Error::Pure, LWP::UserAgent, Unicode::UTF8, WQS::SPARQL,
    WQS::SPARQL::Result.

SEE ALSO
    Wikidata::Reconcilation::Periodical
        Wikidata reconcilation class for periodical.

REPOSITORY
    <https://github.com/michal-josef-spacek/Wikibase-Reconcilation>

AUTHOR
    Michal Josef Špaček <mailto:skim@cpan.org>

    <http://skim.cz>

LICENSE AND COPYRIGHT
    © 2023 Michal Josef Špaček

    BSD 2-Clause License

VERSION
    0.03