/*
  @dataElement: ANC.B8.DE17 Systolic blood pressure
  @activity: ANC.B8. Conduct physical exam
  @description: Systolic blood pressure (SBP) in mmHg
*/
define "Systolic blood pressure":
  [Observation: Cx."Systolic blood pressure"] O
    where O.status in { 'final', 'amended', 'corrected' }
      and Coalesce(WC.ModifierExtension(O, 'who-notDone').value, false) is false

/*
define "Pregnant":
  "Pregnancy" is not null
    or "Pregnancy status" in BCx."Pregnancy status - pregnant"

define "Pregnancy status":
  FHIRHelpers.ToConcept(
    Last(
      [Observation: BCx."Pregnancy status"] O
        where O.status = 'final'
        sort by FHIRHelpers.ToDateTime(effective as FHIR.dateTime)
    ).value
  )
*/

define "Antenatal care case":
  ["EpisodeOfCare": type in BCx."Antenatal care case"]

/*
@description: Most recent antenatal care case
*/
define "Pregnancy":
  First(
    "Antenatal care case" E
		  sort by start of period descending
	)

/*
  @dataElement: ANC.B8.DE19 Diastolic blood pressure
  @activity: ANC.B8. Conduct physical exam
  @description: Diastolic blood pressure (DBP) in mmHg
*/
define "Diastolic blood pressure":
  [Observation: Cx."Diastolic blood pressure"] O
    where O.status in { 'final', 'amended', 'corrected' }
      and Coalesce(WC.ModifierExtension(O, 'who-notDone').value, false) is false

/*
Numerator: Number of antenatal clients with blood pressure measured
Numerator Computation: COUNT of all women who had their blood pressure measured at least once during pregnancy
*/
define Numerator:
  exists (
    PatientData."Systolic blood pressure" O
      where O.issued during BaseData."Pregnancy".period
  )
    or exists (
      PatientData."Diastolic blood pressure" O
        where O.issued during BaseData."Pregnancy".period
    )

/*
By Patient Age as of the start of the Measurement Period
Age (10-14, 15-19, 20+)
*/
define "By Age":
  case
    when AgeInYearsAt(start of "Measurement Period") in Interval[10, 14] then "P10Y--P14Y"
    when AgeInYearsAt(start of "Measurement Period") in Interval[15, 19] then "P15Y--P19Y"
    when AgeInYearsAt(start of "Measurement Period") >= 20 then "P20Y--P9999Y"
    else null
  end

/*
Disaggregation: Age (10-14, 15-19, 20+)
*/
define "Age Stratifier":
  Stratifiers."By Age"

/*
  @dataElement: ANC.End.1 Reason for closing ANC record
  @activity: ANC.End End
  @description: Select the reason why you are closing the woman's ANC record
*/
define "Reason for closing ANC record":
  [Observation: Cx."Reason for closing ANC record"] O
    where O.status in { 'final', 'amended', 'corrected' }
      and Coalesce(WC.ModifierExtension(O, 'who-notDone').value, false) is false

/*
Denominator: Total number of antenatal clients with a first contact
Denominator Computation: COUNT of all women whose records were closed (ANC close form) in the last reporting period due to any of the reasons below:
*live birth
*stillbirth
*miscarriage
*abortion
*woman died
*lost to follow-up
*moved away
*/
define Denominator:
  exists (
    PatientData."Reason for closing ANC record" R
      where FC.ToInterval(R.effective) during "Measurement Period"
        and R.value as FHIR.CodeableConcept in Stratifiers."Qualifying Reason for closing ANC record Choices"
  )

/*
By Patient Education Level (none, don't know, primary, secondary, higher)
*/
define "By Education Level":
  Patient.extension E
    where E.url = 'http://smart.who.int/anc/StructureDefinition/educationlevel'
    return E.value as CodeableConcept

/*
Disaggregation: Education Level (none, don't know, primary, secondary, higher)
*/
define "Education Level Stratifier":
  Stratifiers."By Education Level"

/*
Initial population: Antenatal clients
*/
define "Initial Population":
  exists (BaseData."Antenatal care case")

/*
  @dataElement: ANC.B6.DE17 Gestational age
  @activity: ANC.B6 Profile
  @description: Gestational age in weeks and/or days depending on the source of gestational age
*/
define "Gestational age":
  WC.MostRecent(
  [Observation: Cx."Gestational age"] O
    where O.status in { 'final', 'amended', 'corrected' }
      and Coalesce(WC.ModifierExtension(O, 'who-notDone').value, false) is false
      and Last(Split(O.encounter.reference, '/')) = Last(Split(encounter, '/'))
  ).value as FHIR.Quantity

/*
By Trimester Category: 1st (GA ≤ 12 weeks); 2nd (GA > 12 weeks to ≤ 28 weeks); 3rd (GA > 28 weeks)
*/
define "By Trimester Category":
  case
    when ContactData."Gestational age" <= 12 weeks then 'GA ≤ 12 weeks'
    when ContactData."Gestational age" <= 28 weeks then 'GA > 12 weeks to ≤ 28 weeks'
    else 'GA > 28 weeks'
  end

/*
Disaggregation: Trimester categories: 1st (GA ≤ 12 weeks); 2nd (GA > 12 weeks to ≤ 28 weeks); 3rd (GA > 28 weeks)
*/
define "Trimester Category Stratifier":
  Stratifiers."By Trimester Category"

define function ToString(value ObservationStatus): value.value

define function ToBoolean(value boolean): value.value

/*
@description: Returns the single WHO core modifier extension (if present) on the given resource with the specified id.
@comment: This function uses singleton from to ensure that a run-time exception is thrown if there
is more than one extension on the given resource with the specified url.
*/
define function ModifierExtension(domainResource DomainResource, id String):
  singleton from ModifierExtensions(domainResource, id)

/*
@description: Returns any WHO core modifier extensions defined on the given resource with the specified id.
@comment: NOTE: Extensions are not the preferred approach, but are used as a way to access
content that is defined by extensions but not yet surfaced in the
CQL model info.
*/
define function ModifierExtensions(domainResource DomainResource, id String):
  domainResource.modifierExtension E
	  where E.url = ('http://fhir.org/guides/who/core/StructureDefinition/' + id)
		return E

define function ToString(value uri): value.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 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 ToQuantity(quantity FHIR.Quantity):
    case
        when quantity is null then null
        when quantity.value is null then null
        when quantity.comparator is not null then
            Message(null, true, 'FHIRHelpers.ToQuantity.ComparatorQuantityNotSupported', 'Error', 'FHIR Quantity value has a comparator and cannot be converted to a System.Quantity value.')
        when quantity.system is null or quantity.system.value = 'http://unitsofmeasure.org'
              or quantity.system.value = 'http://hl7.org/fhirpath/CodeSystem/calendar-units' then
            System.Quantity { value: quantity.value.value, unit: ToCalendarUnit(Coalesce(quantity.code.value, quantity.unit.value, '1')) }
        else
            Message(null, true, 'FHIRHelpers.ToQuantity.InvalidFHIRQuantity', 'Error', 'Invalid FHIR Quantity code: ' & quantity.unit.value & ' (' & quantity.system.value & '|' & quantity.code.value & ')')
    end

define function ToCalendarUnit(unit System.String):
    case unit
        when 'ms' then 'millisecond'
        when 's' then 'second'
        when 'min' then 'minute'
        when 'h' then 'hour'
        when 'd' then 'day'
        when 'wk' then 'week'
        when 'mo' then 'month'
        when 'a' then 'year'
        else unit
    end

define function MostRecent(observations List<Observation>):
  Last(
    observations O
      sort by issued
  )

define function ToString(value string): value.value