contract request customer

contract request template model
  def customer
    result = ContractRequestTemplateQuery.fetch_customer(contract_request_template_id: id)
    return nil unless result

    customer_id = result[:customerId].value
    Customer.new(uri: customer_id)
  end

contract request model
  def contract_request_template
    result = ContractRequestQuery.fetch_contract_request_template(contract_request_id: id)
    return nil unless result

    contract_request_template_id = result[:contractRequestTemplateId].value
    ContractRequestTemplate.new(uri: contract_request_template_id)
  end

  delegate :customer, to: :contract_request_template, allow_nil: true



class ContractRequestQuery
  def self.fetch_contract_request_template(contract_request_id:)
    sparql_query = %(
      PREFIX wco: <#{PrefixesService::PREFIXES[:wco]}>
      PREFIX wci: <#{PrefixesService::PREFIXES[:wci]}>

      SELECT ?contractRequestTemplateId
        WHERE { ?contractRequestTemplateId wco:templateFor wci:#{contract_request_id} . }
    )
    result = GraphDBConnector.instance.query(sparql_query)
    return [] unless result[:success]

    result[:data]&.first
  end
end

contract request template query
def fetch_customer(contract_request_template_id:)
      sparql_query = %(
        PREFIX wco: <#{PrefixesService::PREFIXES[:wco]}>
        PREFIX wci: <#{PrefixesService::PREFIXES[:wci]}>

        SELECT ?customerId
        WHERE {
          ?customerId wco:hasContractRequestTemplate wci:#{contract_request_template_id} .
        }
      )
      result = GraphDBConnector.instance.query(sparql_query)
      return [] unless result[:success]

      result[:data]&.first
    end