/* End of Date DSD ART eligibility assessed */

/*
@dataElement: HIV.D.DE762 - Currently enrolled in DSD ART model
@activity: HIV.D21 Determine regimen and treatment options
@description: Client currently enrolled in differentiated service delivery (DSD) ART model
*/

define "Currently enrolled in DSD ART model":
  exists(
    [EpisodeOfCare] EOC
    where exists(EOC.type T where T ~ Concepts."Currently enrolled in DSD ART model")
    and (exists (
      EOC.statusHistory H
      where H.period starts after start of "Measurement Period"
      and H.period starts before end of "Measurement Period"
    ) 
    or (
      EOC.period starts after start of "Measurement Period"
      and EOC.period starts before end of "Measurement Period"
    )
    )
  )

/* End of Time to start ART */

/*
@dataElement: HIV.D.DE387 - Viral load test result
@activity: HIV.D20 Diagnostics
@description: Result from the viral load test in number of copies/mL
*/

define "Viral load test result D.DE387":
  [Observation: Concepts."Viral load test result - HIV.D.DE387"] O
    where O.status in { 'final', 'amended', 'corrected' }

/* End of Date of baseline CD4 count test D.DE368 */

/*
@dataElement: HIV.D.DE387 - Viral load test result
@activity: HIV.D20 Diagnostics
@description: Result from the viral load test in number of copies/mL
*/

define "Viral load test result D.DE387":
  Elements."Viral load test result D.DE387" O
    where O.effective.toInterval() during "Measurement Period"

define "routine viral load sample collection":
  [Procedure] P
  where P.status = 'completed'
  and P.code ~ ConceptsCustom."viral load test"
  and exists(P.reasonCode RC where RC ~ Concepts."Routine viral load test")

/**
 * Numerator
 * 
 * Definition: Number of people enrolled in a DSD ART model with at least one routine viral load test during the reporting period who have virological suppression (<1000 copies/mL) at 6 months after ART initiation and yearly thereafter (that is, at 24, 36, 48 and 60 months, etc. after ART initiation).
 * Calculation: COUNT of clients with "Currently enrolled in DSD ART model"=True AND "Date of viral load sample collection" during the reporting period AND "Reason for HIV viral load test"='Routine viral load test' AND "Viral load test result" LESS THAN 1000 copies/mL
 */

define "Numerator":
  HIE."Currently enrolled in DSD ART model"
   and exists(
    HIE."Viral load test result D.DE387" VL
    with HE."routine viral load sample collection" P 
    such that VL.partOf.references(P) and  P.performed.toInterval() during "Measurement Period"
    where VL.value < 1000
    )

/**
 * Denominator
 *
 * Definition: Number of people enrolled in a DSD ART model with at least one routine viral load result in a medical or laboratory record during the reporting period
 * Calculation: COUNT of clients with "Currently enrolled in DSD ART model"=True AND "Date of viral load sample collection" during the reporting period AND "Reason for HIV viral load test"='Routine viral load test'
 */

define "Denominator":
  HIE."Currently enrolled in DSD ART model"
   and exists(
    HIE."Viral load test result D.DE387" VL
    with HE."routine viral load sample collection" P 
    such that VL.partOf.references(P) and  P.performed.toInterval() during "Measurement Period"
    )

/* Populations */

/*
 *Initial Population
 */

define "Initial Population":
  true

/*
@dataElement: HIV.A.DE18 - Gender
@activity: HIV.A6.1 Review sociodemographic data with client | HIV.A5 Create new client record
@description: Gender of the client
*/

/*
 * By Administrative Gender of Patient Stratifier
 * Need to expand codes
 */

define "By Administrative Gender Stratifier":
  case 
      when Patient.gender = 'male' then Concepts."Male"
      when Patient.gender = 'female' then Concepts."Female"
      when Patient.gender = 'transgender female' then Concepts."Transgender female"
      when Patient.gender = 'transgender male' then Concepts."Transgender male"
      else Concepts."Other - HIV.A.DE23"
  end

/* End of Visit date A.DE3 */

/*
@dataElement: HIV.A.DE17 - Age
@activity: HIV.A6.1 Review sociodemographic data with client | HIV.A5 Create new client record
@description: Calculated age (number of years) of the client based on date of birth
*/
define "Age In Years":
  AgeInYearsAt(start of "Measurement Period")

//(0–4, 5–14, 15–24, 25+ years) 
define "By Age Stratifier 8":
  case 
      when "Age In Years" <= 4 then '0-4'
      when "Age In Years" <= 14 then '5-14'
      when "Age In Years" <= 24 then '15-24'
      when "Age In Years" >= 25 then '25+'
      else null
  end

// Geographic Region
define "By Geographic Region Stratifier":
    First(Patient.address A where A.use in { 'home' }).state

/* End of Key population member B.DE49 */

/*
@dataElement: HIV.B.DE50 - Key population member type
@activity: HIV.B6 Capture or update client history
@description: The type of key population that the client is included in
*/
define "Key population member type Observation":
  [Observation: Concepts."Key population member - HIV.B.DE49"] O
    where O.status in { 'final', 'amended', 'corrected' }
    and exists(O.category OC where OC ~ ConceptsCustom."social-history")

define "Key population member type Observation":
  Elements."Key population member type Observation" O
    where O.effective.toInterval() before end of "Measurement Period"
    or O.issued before end of "Measurement Period"

// Stratifier
define patientGroups:
  "Key population member type Observation" O
  return Combine(O.code.coding.code, ':')

define "Stratification":
 HIE."By Administrative Gender Stratifier".code 
  + ':' + HIE."By Age Stratifier 8"
+ ':' + HIE."By Geographic Region Stratifier"
+ Combine(HIE.patientGroups, ':')

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 ToInterval(period FHIR.Period):
    if period is null then
        null
    else
        if period."start" is null then
            Interval(period."start".value, period."end".value]
        else
            Interval[period."start".value, period."end".value]

define function ToString(value ObservationStatus): 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

define function ToInteger(value integer): value.value

define function ToString(value AdministrativeGender): value.value

define function ToString(value AddressUse): value.value

define function ToDateTime(value instant): value.value