# encoding: UTF-8

# Copyright 2011 innoQ Deutschland GmbH
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

class Concept::Relation::SKOS::Base < Concept::Relation::Base

  self.rdf_namespace = 'skos'

  def self.build_from_rdf(rdf_subject, rdf_predicate, rdf_object)
    raise "#{self.name}#build_from_rdf: Subject (#{rdf_subject}) must be a Concept." unless rdf_subject.is_a? Concept::Base
    raise "#{self.name}#build_from_rdf: Object (#{rdf_object}) must be a Concept."   unless rdf_object.is_a? Concept::Base

    relation_class = Iqvoc::RDFAPI::PREDICATE_DICTIONARY[rdf_predicate] || self

    relation_instance = rdf_subject.send(self.name.to_relation_name).select{|rel| rel.target == rdf_object}
    if relation_instance.empty?
      relation_instance = relation_class.new(:target => rdf_object)
      rdf_subject.send(self.name.to_relation_name) << relation_instance
    end

    if relation_class.bidirectional?
      reverse_class      = relation_class.reverse_relation_class
      reverse_collection = rdf_object.send(reverse_class.name.to_relation_name)
      if reverse_collection.select{|rel| rel.target == rdf_subject}.empty?
        reverse_instance = reverse_class.new(:target => rdf_subject)
        reverse_collection << reverse_instance
      end
    end
  end

  def build_rdf(document, subject)
    subject.send(self.rdf_namespace.camelcase).send(self.rdf_predicate, IqRdf.build_uri(target.origin))

    # Auto-include preferred labels for referenced concepts
    document << IqRdf::build_uri(target.origin) do |subject|
      target.pref_labelings.each do |labeling|
        subject.skos.send(labeling.rdf_predicate, labeling.target.value.to_s, :lang => labeling.target.language)
      end
    end
  end

end