/*
 * As defined by Member State
 */
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")

/*
 * By Age Stratifiers
 * (0–4, 5–9, 10–14, 15–19, 20–24, 25–29, 30–34, 35–39, 40–44, 45–49, 50+ years)
 * 
 */
define "By Age Stratifier":
  case 
      when "Age In Years" <= 4 then '0-4'
      when "Age In Years" <= 9 then '5-9'
      when "Age In Years" <= 14 then '10–14'
      when "Age In Years" <= 19 then '15–19'
      when "Age In Years" <= 24 then '20–24'
      when "Age In Years" <= 29 then '25–29'
      when "Age In Years" <= 34 then '30–34'
      when "Age In Years" <= 39 then '35–39'
      when "Age In Years" <= 44 then '40–44'
      when "Age In Years" <= 49 then '45–49'
      when "Age In Years" >= 50 then '50+'
      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, ':')

/* 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()

define "LTFU Days":
  28 days

/* End of HIV treatment outcome */

/*
@dataElement: HIV.H.DE42 - Lost to follow-up
@activity: HIV.H3 Record outreach and result
@description: Twenty-eight days or more since last missed appointment 
*/
define "Lost to follow-up":
  Elements."On ART H.DE47" H
   where H.effective starts before end of "Measurement Period"
    and H.effective ends after start of "Measurement Period"
	and not (H.effective ends after (end of "Measurement Period" - Config."LTFU Days"))

define "Is lost to follow-up":
  exists("Lost to follow-up")

define "Transferred out status":
    [EpisodeOfCare] EOC
    where exists(EOC.type T where T ~ Concepts."On ART - HIV.H.DE47")
      and EOC.status = 'finished'
    return EOC.period

define "Transferred out statusHistory":
    [EpisodeOfCare] EOC
    where exists(EOC.type T where T ~ Concepts."On ART - HIV.H.DE47") 
    and (exists (
      EOC.statusHistory H
      where H.status = 'finished'
      and H.period is not null))

define "Transferred out":
  flatten{"Transferred out status","Transferred out statusHistory".statusHistory.period}

/* End of Lost to follow-up */

/*
@dataElement: HIV.H.DE43 - Transferred out
@activity: HIV.H3 Record outreach and result
@description: The client transferred to another facility
*/

define "Has transferred out":
  exists(Elements."Transferred out" t where t ends during "Measurement Period")

/* End of Transferred out */

/*
@dataElement: HIV.H.DE44 - Death documented
@activity: HIV.H3 Record outreach and result
@description: People living with HIV previously on ART who are confirmed to have died from any cause
*/
define "Death documented":
  case 
    when Patient.deceased is FHIR.boolean and Patient.deceased ~ true then Patient.meta.lastUpdated.value
    when Patient.deceased is FHIR.dateTime then Patient.deceased as FHIR.dateTime
    else null
  end

/* End of Transferred out */

/*
@dataElement: HIV.H.DE44 - Death documented
@activity: HIV.H3 Record outreach and result
@description: People living with HIV previously on ART who are confirmed to have died from any cause
*/
define "Has death documented":
  Elements."Death documented" before end of "Measurement Period"

/* End of Death documented */

/*
@dataElement: HIV.H.DE45 - Refused stopped treatment
@activity: HIV.H3 Record outreach and result
@description: Client was contacted and confirmed to have stopped ART (reasons may include stigma and discrimination, faith healing, etc.)
*/

define "Refused stopped treatment":
  [MedicationStatement] MS
    where MS.status in {'stopped'}
    and exists(MS.reasonCode C where C ~ Concepts."On ART - HIV.H.DE47")
    and exists(MS.statusReason R where R ~ Concepts."Refused stopped treatment")
    sort by start of effective.toInterval()

/* End of Death documented */

/*
@dataElement: HIV.H.DE45 - Refused stopped treatment
@activity: HIV.H3 Record outreach and result
@description: Client was contacted and confirmed to have stopped ART (reasons may include stigma and discrimination, faith healing, etc.)
*/

define "Refused stopped treatment":
    exists(Elements."Refused stopped treatment" O where O.effective.toInterval() during "Measurement Period")

/* 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 "Treatment outcome category":
  List<String>{
    if "Is lost to follow-up" then 'LTFU' else null,
    if "Has transferred out" then 'Transfer Out' else null,
    if "Has death documented" then 'Death' else null,
    if "Refused stopped treatment" then 'Stopped' else null,
    if "On ART H.DE47" then 'On ART' else null
  }

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

define function ToString(value AdministrativeGender): value.value

define function ToString(value string): value.value

define function ToString(value AddressUse): value.value

define function ToString(value ObservationStatus): value.value

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 instant): 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 EpisodeOfCareStatus): value.value

define function ToBoolean(value boolean): value.value

define function ToDateTime(value dateTime): value.value

define function ToString(value MedicationStatementStatus): value.value