define "HIV Status Positive Condition":
  [Condition: Concepts."HIV-positive - HIV.B.DE116"] C
    where C.clinicalStatus ~ ConceptsCustom."active"
      and exists(C.category CC where CC ~ ConceptsCustom."encounter-diagnosis")
    sort by start of onset.toInterval()

define "HIV Status Positive Condition":
  Elements."HIV Status Positive Condition" C
  where C.onset before end of "Measurement Period"

/* End of HIV-inconclusive */

/*
@dataElement: HIV.B.DE115 - HIV status
@activity: HIV.B7 Test for HIV using testing algorithm
@description: HIV status reported after applying the national HIV testing algorithm. No single HIV test can provide an HIV-positive diagnosis.
*/
define "HIV Status Observation":
  [Observation: Concepts."HIV status"] O
    where O.status in { 'final', 'amended', 'corrected' }

define "HIV Status Positive Observation":
"HIV Status Observation" O
    where O.value ~ Concepts."HIV-positive - HIV.B.DE116"
      sort by start of effective.toInterval()

define "HIV Status Positive Observation":
  Elements."HIV Status Positive Observation" O
  where O.issued before end of "Measurement Period"
  or O.effective.toInterval() starts before end of "Measurement Period"

define "Has HIV-positive Status":
  exists "HIV Status Positive Condition"
  or exists "HIV Status Positive Observation"

/* End of HBsAg test date D.DE161 */


/*
@dataElement: HIV.D.DE162 - HBsAg test result
@activity: HIV.D12 Determine recommended screenings and tests
@description: Hepatitis B virus test result (HBsAg)
*/

define "HBsAg test result D.DE162":
  [Observation: Concepts."HBsAg test result - HIV.D.DE162"] O
    where O.status in { 'final', 'amended', 'corrected' }

/* End of HBsAg test result D.DE162 */

/*
@dataElement: HIV.D.DE163 - Positive
@activity: HIV.D12 Determine recommended screenings and tests
@description: HBsAg test result was positive
*/

define "Positive D.DE163":
  "HBsAg test result D.DE162" O
  where O.value ~ Concepts."Positive - HIV.D.DE163"

/* End of STI testing and treatment D.DE160 */

/*
@dataElement: HIV.D.DE161 - HBsAg test date
@activity: HIV.D12 Determine recommended screenings and tests
@description: Date client was tested for hepatitis B virus (HBV)
*/

define "HBsAg test date D.DE161":
  [Procedure] P
  where P.status = 'completed'
  and P.code ~ ConceptsCustom."HBsAg test"

/**
 * Numerator
 * 
 * Definition: Number of people living with HIV who tested positive for HBsAg during the reporting period
 * Calculation: COUNT of clients with "HIV status"='HIV-positive' AND "HBsAg test date" in the reporting period AND "HBsAg test result"='HBsAg positive
 */

define "Numerator":
  HIE."Has HIV-positive Status" and
  exists(HE."Positive D.DE163" G
  with HE."HBsAg test date D.DE161" P
  such that G.partOf.references(P) and P.performed.toInterval() during "Measurement Period")

/* End of Current ART regimen */

/*
@dataElement: HIV.D.DE161 - HBsAg test date
@activity: HIV.D12 Determine recommended screenings and tests
@description: Date client was tested for hepatitis B virus (HBV)
*/
//TODO - verify
define "HBsAg test date D.DE161":
  exists(Elements."HBsAg test date D.DE161" P
    where P.performed.toInterval() during "Measurement Period")

/**
 * Denominator
 *
 * Definition: Number of people living with HIV tested for HBsAg during the reporting period
 * Calculation: COUNT of clients with "HIV status"='HIV-positive' AND "HBsAg test date" in the reporting period
 */

define "Denominator":
  HIE."Has HIV-positive Status" and HIE."HBsAg test date D.DE161"

/* Populations */

/*
 *Initial Population
 */

define "Initial Population":
  true

define function ToConcept(concept FHIR.CodeableConcept):
    if concept is null then
        null
    else
        System.Concept {
            codes: concept.coding C return ToCode(C),
            display: concept.text.value
        }

define function ToCode(coding FHIR.Coding):
    if coding is null then
        null
    else
        System.Code {
          code: coding.code.value,
          system: coding.system.value,
          version: coding.version.value,
          display: coding.display.value
        }

define function ToDateTime(value dateTime): value.value

define function ToString(value ObservationStatus): value.value

define function ToDateTime(value instant): value.value

define function ToString(value ProcedureStatus): value.value

/*
@description: Returns true if any of the given references are to the given resource
@comment: Returns true if the `id` element of the given resource exactly equals the tail of any of the given references.
NOTE: This function assumes resources from the same source server.
*/
define fluent function references(references List<FHIR.Reference>, resource FHIR.Resource):
  exists (references R where R.references(resource))

/*
@description: Returns true if the given reference is to the given resource
@comment: Returns true if the `id` element of the given resource exactly equals the tail of the given reference.
NOTE: This function assumes resources from the same source server.
*/
define fluent function references(reference FHIR.Reference, resource FHIR.Resource):
  resource.id = Last(Split(reference.reference, '/'))

define function ToString(value string): value.value