module HealthDataStandards
  module Validate
module ReportedResultExtractor

    #takes a document and a list of 1 or more id hashes, e.g.:
      #[{measure_id:"8a4d92b2-36af-5758-0136-ea8c43244986", set_id:"03876d69-085b-415c-ae9d-9924171040c2", ipp:"D77106C4-8ED0-4C5D-B29E-13DBF255B9FF", den:"8B0FA80F-8FFE-494C-958A-191C1BB36DBF", num:"9363135E-A816-451F-8022-96CDA7E540DD"}]
      #returns nil if nothing matching is found
      # returns a hash with the values of the populations filled out along with the population_ids added to the result


      def extract_results_by_ids(measure_id, ids, doc)
        results = nil
        _ids = ids.dup
        stratification = _ids.delete("stratification")
        stratification ||= _ids.delete("STRAT")
        errors = []
        nodes = find_measure_node(measure_id, doc)

        if nodes.nil? || nodes.empty?
          # short circuit and return nil
          return {}
        end

        nodes.each do |n|
         results =  get_measure_components(n, _ids, stratification)
         break if (results != nil || (results != nil && !results.empty?))
        end
        return nil if results.nil?
        results[:population_ids] = ids.dup
        results
      end

      def find_measure_node(id, doc)
         xpath_measures = %Q{/cda:ClinicalDocument/cda:component/cda:structuredBody/cda:component/cda:section
          /cda:entry/cda:organizer[ ./cda:templateId[@root = "2.16.840.1.113883.10.20.27.3.1"]
          and ./cda:reference/cda:externalDocument/cda:id[#{translate("@extension")}='#{id.upcase}' and #{translate("@root")}='2.16.840.1.113883.4.738']]}
         return doc.xpath(xpath_measures)
      end

      def get_measure_components(n,ids, stratification)
        results = {:supplemental_data =>{}}
        ids.each_pair do |k,v|
          val = nil
          sup = nil
          if (k == 'OBSERV')
            msrpopl = ids['MSRPOPL']
            val, sup = extract_cv_value(n,v,msrpopl, stratification)
          else
            val,sup,pr =extract_component_value(n,k,v,stratification)
          end
          if !val.nil?
            results[k.to_s] = val
            results[:supplemental_data][k] = sup
          else
            # return nil
          end
          if !pr.nil?
            results["PR"] = pr
          end
        end
        results
      end

    def extract_cv_value(node, id, msrpopl, strata = nil)
        xpath_observation = %{ cda:component/cda:observation[./cda:value[@code = "MSRPOPL"] and ./cda:reference/cda:externalObservation/cda:id[#{translate("@root")}='#{msrpopl.upcase}']]}
        cv = node.at_xpath(xpath_observation)
        return nil unless cv
        val = nil
        if strata
        strata_path = %{ cda:entryRelationship[@typeCode="COMP"]/cda:observation[./cda:templateId[@root = "2.16.840.1.113883.10.20.27.3.4"]  and ./cda:reference/cda:externalObservation/cda:id[#{translate("@root")}='#{strata.upcase}']]}
        n = cv.xpath(strata_path)
        val = get_cv_value(n,id)
        else
        val = get_cv_value(cv,id)
        end
        return val, (strata.nil? ?  extract_supplemental_data(cv) : nil)
      end

      def extract_component_value(node, code, id, strata = nil)
        xpath_observation = %{ cda:component/cda:observation[./cda:value[@code = "#{code}"] and ./cda:reference/cda:externalObservation/cda:id[#{translate("@root")}='#{id.upcase}']]}
        cv = node.at_xpath(xpath_observation)
        return nil unless cv
        val = nil
        if strata
          strata_path = %{ cda:entryRelationship[@typeCode="COMP"]/cda:observation[./cda:templateId[@root = "2.16.840.1.113883.10.20.27.3.4"]  and ./cda:reference/cda:externalObservation/cda:id[#{translate("@root")}='#{strata.upcase}']]}
          n = cv.xpath(strata_path)
          val = get_aggregate_count(n) if n
        else
          val = get_aggregate_count(cv)
        end
        #Performance rate is only applicable for unstratified values
        if code == "NUMER" && strata == nil
          pref_rate_value = extract_performance_rate(node,code,id)
        end
        return val,(strata.nil? ?  extract_supplemental_data(cv) : nil),pref_rate_value
      end

    def extract_performance_rate(node,code,id)
        xpath_perf_rate = %{ cda:component/cda:observation[./cda:templateId[@root = "2.16.840.1.113883.10.20.27.3.14"] and ./cda:reference/cda:externalObservation/cda:id[#{translate("@root")}='#{id.upcase}']]/cda:value}
        perf_rate = node.at_xpath(xpath_perf_rate)
        pref_rate_value = {}
        if perf_rate != nil
          if perf_rate.at_xpath("./@nullFlavor")
            pref_rate_value["nullFlavor"] = "NA"
            return pref_rate_value
          else
            pref_rate_value["value"] = perf_rate.at_xpath("./@value").value
            return pref_rate_value
          end
        end
        return nil
      end
          # convert numbers in value nodes to Int / Float as necessary TODO add more types other than 'REAL'
      def convert_value(value_node)
        if value_node.nil?
          return
        end
        if value_node['type'] == 'REAL' || value_node['value'].include?('.')
          return value_node['value'].to_f
        else
          return value_node['value'].to_i
        end
      end

      #given an observation node with an aggregate count node, return the reported and expected value within the count node
      def get_cv_value(node, cv_id)
        xpath_value = %{cda:entryRelationship/cda:observation[./cda:templateId[@root="2.16.840.1.113883.10.20.27.3.2"] and ./cda:reference/cda:externalObservation/cda:id[#{translate("@root")}='#{cv_id.upcase}']]/cda:value}

        value_node = node.at_xpath(xpath_value)
        value = convert_value(value_node) if value_node
        value
      end

      #given an observation node with an aggregate count node, return the reported and expected value within the count node
      def get_aggregate_count(node)
        xpath_value = 'cda:entryRelationship/cda:observation[./cda:templateId[@root="2.16.840.1.113883.10.20.27.3.3"]]/cda:value'
        value_node = node.at_xpath(xpath_value)
        value = convert_value(value_node) if value_node
        value
      end

      def extract_supplemental_data(cv)
        ret = {}
        supplemental_data_mapping = {"RACE"=> "2.16.840.1.113883.10.20.27.3.8",
                             "ETHNICITY" => "2.16.840.1.113883.10.20.27.3.7",
                             "SEX" => "2.16.840.1.113883.10.20.27.3.6",
                             "PAYER" => "2.16.840.1.113883.10.20.27.3.9"}
        supplemental_data_mapping.each_pair do |supp, id|
          key_hash = {}
          xpath = "cda:entryRelationship/cda:observation[cda:templateId[@root='#{id}']]"
          (cv.xpath(xpath) || []).each do |node|
            value = node.at_xpath('cda:value')
            count = get_aggregate_count(node)
            if value.at_xpath("./@nullFlavor")
             key_hash["UNK"] = count
            else
             key_hash[value['code']] = count
            end
          end
          ret[supp.to_s] = key_hash
        end
        ret
      end

      def translate(id)
        %{translate(#{id}, "abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZ")}
      end
    end
end
end