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 Refused stopped treatment */

/*
@dataElement: HIV.H.DE47 - On ART
@activity: HIV.H3 Record outreach and result
@description: Client is currently taking ART 
*/

define "On ART H.DE47":
    [MedicationStatement] MS
    where exists(MS.reasonCode C where C ~ Concepts."On ART - HIV.H.DE47")
    sort by start of effective.toInterval()

/* End of Refused stopped treatment */

/*
@dataElement: HIV.H.DE47 - On ART
@activity: HIV.H3 Record outreach and result
@description: Client is currently taking ART 
*/
define "On ART H.DE47":
  exists(Elements."On ART H.DE47" ART
   where ART.effective.toInterval() during "Measurement Period"
   )

define "DSD ART status":
    [EpisodeOfCare] EOC
    where exists(EOC.type T where T ~ Concepts."Currently enrolled in DSD ART model")
      and EOC.status = 'finished'
    return EOC.period

define "DSD ART statusHistory":
    [EpisodeOfCare] EOC
    where exists(EOC.type T where T ~ Concepts."Currently enrolled in DSD ART model") 
    and (exists (
      EOC.statusHistory H
      where H.status = 'finished'
      and H.period is not null))

/* End of Currently enrolled in DSD ART model */

/*
@dataElement: HIV.D.DE763 - DSD ART start date
@activity: HIV.D21 Determine regimen and treatment options
@description: Date client started on differentiated service delivery (DSD) for ART
*/

define "DSD ART start date":
  flatten{"DSD ART status","DSD ART statusHistory".statusHistory.period}

define "DSD Retention Interval":
  12 months

/* 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"
    )
    )
  )

/**
 * Numerator
 * 
 * Definition: Number of people on ART known to be on treatment 12 months after enrolling in a DSD ART model* (also at 24, 36, 48, 60 months, etc. after enrolment in the model)
 * Calculation: COUNT of clients with "HIV status"='HIV-positive' AND "On ART"=True AND "DSD ART start date">X months before reporting period end date AND "Currently enrolled in DSD ART model"=True |  | Reported where 'X' is 12, 24, 36, 48, or 60 months
 */
  

define "Numerator":
  HIE."Has HIV-positive Status"
   and HIE."On ART H.DE47"
   and exists(HE."DSD ART start date" t where months between start of t and end of "Measurement Period" >= Config."DSD Retention Interval")
   and HIE."Currently enrolled in DSD ART model"

/**
 * Denominator
 *
 * Definition: Number of people on ART enrolled in a DSD ART model 12 months ago, excluding individuals who transferred out (also 24, 36, 48, 60 months ago, etc.)
 * Calculation: COUNT of clients with "HIV status"='HIV-positive' AND "On ART"=True AND "DSD ART start date">X months before reporting period end date |  | Reported where 'X' is 12, 24, 36, 48, or 60 months
 */

define "Denominator":
  HIE."Has HIV-positive Status"
   and HIE."On ART H.DE47"
   and exists(HE."DSD ART start date" t where months between start of t and end of "Measurement Period" >= Config."DSD Retention Interval")

/* 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 ToDateTime(value dateTime): value.value

define function ToString(value ObservationStatus): value.value

define function ToDateTime(value instant): value.value

define function ToString(value EpisodeOfCareStatus): value.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 AdministrativeGender): value.value

define function ToString(value string): value.value

define function ToString(value AddressUse): value.value