define "Initial Population":
  AgeInYearsAt(date from start of "Measurement Period") in Interval[18, 85]
    and "Has Active Diabetes Overlaps Start Of Measurement Period"
    and "Has Outpatient Visit During Measurement Period"

define "Denominator":
  "Initial Population"

define "Denominator Exclusions":
  "Has CKD Stage 5 Or ESRD Diagnosis Overlaps Measurement Period"
    or Hospice."Has Hospice Services"
    or PalliativeCare."Has Palliative Care in the Measurement Period"

define "Numerator":
  "Kidney Panel Performed During Measurement Period"

define "Has Hospice Services":
  exists ((([USQualityCore.Encounter: "Encounter Inpatient"]).isEncounterPerformed()) InpatientEncounter
      where (InpatientEncounter.hospitalization.dischargeDisposition ~ "Discharge to home for hospice care (procedure)"
          or InpatientEncounter.hospitalization.dischargeDisposition ~ "Discharge to healthcare facility for hospice care (procedure)"
      )
        and InpatientEncounter.period ends during day of "Measurement Period"
  )
    or exists ((([USQualityCore.Encounter: "Hospice Encounter"]).isEncounterPerformed()) HospiceEncounter
        where HospiceEncounter.period overlaps day of "Measurement Period"
    )
    // TODO: Shouldn't need to specify a code path here (see https://jira.hl7.org/browse/FHIR-53941)
    or exists ((([USQualityCore.ObservationScreeningAssessment: code ~ "Hospice care [Minimum Data Set]"]).isAssessmentPerformed()) HospiceAssessment
        where HospiceAssessment.value ~ "Yes (qualifier value)"
          and HospiceAssessment.effective.toInterval() overlaps day of "Measurement Period"
    )
    or exists ((([USQualityCore.ServiceRequest: "Hospice Care Ambulatory"]).isInterventionOrder()) HospiceOrder
        where HospiceOrder.authoredOn during day of "Measurement Period"
    )
    or exists ((([USQualityCore.Procedure: "Hospice Care Ambulatory"]).isInterventionPerformed()) HospicePerformed
        where HospicePerformed.performed.toInterval() overlaps day of "Measurement Period"
    )
    // TODO: Consider whether to keep this as the union of Problems and EncounterDiagnosis
    or exists ((([FHIR.Condition: "Hospice Diagnosis"]).verified()) HospiceCareDiagnosis
        where HospiceCareDiagnosis.prevalenceInterval() overlaps day of "Measurement Period"
    )

define "Has Palliative Care in the Measurement Period":
  // TODO: Shouldn't need to specify a code path here (see https://jira.hl7.org/browse/FHIR-53941)
  exists ((([USQualityCore.ObservationScreeningAssessment: code ~ "Functional Assessment of Chronic Illness Therapy - Palliative Care Questionnaire (FACIT-Pal)"]).isAssessmentPerformed()) PalliativeAssessment
      where PalliativeAssessment.effective.toInterval() overlaps day of "Measurement Period"
  )
    // TODO: Consider whether to keep this as the union of the problems and encounter diagnosis list? Anything enforced by the profiles that is expected but isn't stated here?
    or exists ((([FHIR.Condition: "Palliative Care Diagnosis"]).verified()) PalliativeDiagnosis
        where PalliativeDiagnosis.prevalenceInterval() overlaps day of "Measurement Period"
    )
    or exists ((([USQualityCore.Encounter: "Palliative Care Encounter"]).isEncounterPerformed()) PalliativeEncounter
        where PalliativeEncounter.period overlaps day of "Measurement Period"
    )
    or exists ((([USQualityCore.Procedure: "Palliative Care Intervention"]).isInterventionPerformed()) PalliativeIntervention
        where PalliativeIntervention.performed.toInterval() overlaps day of "Measurement Period"
    )

define "SDE Sex":
  case
    when Patient.sex() = '248153007' then "Male (finding)"
    when Patient.sex() = '248152002' then "Female (finding)"
    else null
  end

define "SDE Payer":
  [USQualityCore.Coverage: type in "Payer Type"] Payer
    return {
      code: Payer.type,
      period: Payer.period
    }

define "SDE Ethnicity":
  (Patient.ethnicity()) E
    return Tuple {
      codes: { E.ombCategory } union E.detailed,
      display: E.text
    }

define "SDE Race":
  (Patient.race()) R
    return Tuple {
      codes: R.ombCategory union R.detailed,
      display: R.text
    }

define "SDE Sex":
  SDE."SDE Sex"

define "Has Estimated Glomerular Filtration Rate Performed During Measurement Period":
  exists ( ["LaboratoryResultObservation": "Estimated Glomerular Filtration Rate"] eGFRTest
      where eGFRTest.effective.toInterval ( ) during day of "Measurement Period"
        and eGFRTest.value is not null
        and eGFRTest.status in { 'final', 'amended', 'corrected' }
  )

define "Has Urine Albumin Creatinine Ratio Test Performed During Measurement Period":
  exists ( ["LaboratoryResultObservation": "Urine Albumin Creatinine Ratio"] uACRTest
      where uACRTest.effective.toInterval ( ) during day of "Measurement Period"
        and uACRTest.status in { 'final', 'amended', 'corrected' }
        and ( ( uACRTest.value is Quantity )
            or ( uACRTest.value as FHIR.CodeableConcept in "Undetectable Lab Result Value" )
        )
  )

define "Urine Albumin Test Performed During The Measurement Period":
  ["LaboratoryResultObservation": "Urine Albumin"] AlbuminTest
    where AlbuminTest.effective.toInterval ( ) during day of "Measurement Period"
      and AlbuminTest.value is not null
      and AlbuminTest.status in { 'final', 'amended', 'corrected' }

define "Urine Creatinine Test Performed During The Measurement Period":
  ["LaboratoryResultObservation": "Urine Creatinine"] CreatinineTest
    where CreatinineTest.effective.toInterval ( ) during day of "Measurement Period"
      and CreatinineTest.value is not null
      and CreatinineTest.status in { 'final', 'amended', 'corrected' }

define "Has Urine Albumin Test And Urine Creatine Test Less Than Or Equal To Four Days Apart":
  exists ( from
      "Urine Albumin Test Performed During The Measurement Period" UrineAlbuminTest,
      "Urine Creatinine Test Performed During The Measurement Period" UrineCreatinineTest
      let UrineAlbuminDocumentedTime: UrineAlbuminTest.effective.toInterval ( ),
      UrineCreatinineDocumentedTime: UrineCreatinineTest.effective.toInterval ( )
      where UrineAlbuminDocumentedTime during Interval[start of UrineCreatinineDocumentedTime - 4 days, end of UrineCreatinineDocumentedTime + 4 days]
  )

define "Kidney Panel Performed During Measurement Period":
  "Has Estimated Glomerular Filtration Rate Performed During Measurement Period"
    and ( "Has Urine Albumin Creatinine Ratio Test Performed During Measurement Period"
        or "Has Urine Albumin Test And Urine Creatine Test Less Than Or Equal To Four Days Apart"
    )

define "Numerator":
  "Kidney Panel Performed During Measurement Period"

define "Has Active Diabetes Overlaps Start Of Measurement Period":
  exists ( ["ConditionProblemsHealthConcerns": "Diabetes"]
    union ["ConditionEncounterDiagnosis": "Diabetes"] ) DiabetesDiagnosis
    where DiabetesDiagnosis.onset.toInterval ( ) overlaps before day of "Measurement Period"
      and ( DiabetesDiagnosis.verificationStatus is not null implies ( DiabetesDiagnosis.verificationStatus !~ Status."refuted"
            and DiabetesDiagnosis.verificationStatus !~ Status."entered-in-error"
        )
      )

define "Has Outpatient Visit During Measurement Period":
  exists ( ( ["Encounter": "Annual Wellness Visit"]
      union ["Encounter": "Home Healthcare Services"]
      union ["Encounter": "Office Visit"]
      union ["Encounter": "Outpatient Consultation"]
      union ["Encounter": "Preventive Care Services Established Office Visit, 18 and Up"]
      union ["Encounter": "Preventive Care Services Initial Office Visit, 18 and Up"]
      union ["Encounter": "Telephone Visits"] ) ValidEncounter
      where ValidEncounter.period during day of "Measurement Period"
        and ValidEncounter.status = 'finished'
  )

define "Initial Population":
  AgeInYearsAt(date from start of "Measurement Period") in Interval[18, 85]
    and "Has Active Diabetes Overlaps Start Of Measurement Period"
    and "Has Outpatient Visit During Measurement Period"

define "Denominator":
  "Initial Population"

define "SDE Payer":
  SDE."SDE Payer"

define "SDE Ethnicity":
  SDE."SDE Ethnicity"

define "Has CKD Stage 5 Or ESRD Diagnosis Overlaps Measurement Period":
  exists ( ( ["ConditionProblemsHealthConcerns": "Chronic Kidney Disease, Stage 5"]
      union ["ConditionEncounterDiagnosis": "Chronic Kidney Disease, Stage 5"]
  )
    union ( ["ConditionProblemsHealthConcerns": "End Stage Renal Disease"]
        union ["ConditionEncounterDiagnosis": "End Stage Renal Disease"]
    ) ) CKDOrESRD
    where CKDOrESRD.onset.toInterval ( ) overlaps day of "Measurement Period"
      and ( CKDOrESRD.verificationStatus is not null implies ( CKDOrESRD.verificationStatus !~ Status."refuted"
            and CKDOrESRD.verificationStatus !~ Status."entered-in-error"
        )
      )

define "Denominator Exclusions":
  "Has CKD Stage 5 Or ESRD Diagnosis Overlaps Measurement Period"
    or Hospice."Has Hospice Services"
    or PalliativeCare."Has Palliative Care in the Measurement Period"

define "SDE Race":
  SDE."SDE Race"

//Encounter, Performed
//General usage unless required otherwise by measure intent (e.g., follow-up encounters)
define fluent function isEncounterPerformed(Enc List<FHIR.Encounter>):
  Enc E
    where E.status = 'finished'

//Assessment, Performed
define fluent function isAssessmentPerformed(Obs List<ObservationScreeningAssessment>):
  Obs O
    where O.status in { 'final', 'amended', 'corrected' }

//Intervention, Order
define fluent function isInterventionOrder(ServiceRequest List<FHIR.ServiceRequest>):
  ServiceRequest S
    where S.status in { 'active', 'completed' }
      and S.intent in {'order', 'original-order', 'reflex-order', 'filler-order', 'instance-order'}

//Intervention, Performed
define fluent function isInterventionPerformed(Proc List<FHIR.Procedure>):
  Proc P
    where P.status ~ 'completed'

define function ToString(value string): value.value

define function ToString(value uri): value.value

define function ToDateTime(value dateTime): value.value

/*
@description: Converts the given [Period](https://hl7.org/fhir/datatypes.html#Period)
value to a CQL DateTime Interval
@comment: If the start value of the given period is unspecified, the starting
boundary of the resulting interval will be open (meaning the start of the interval
is unknown, as opposed to interpreted as the beginning of time).
*/
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 ToDateTime(value instant): value.value

define function ToDate(value date): value.value

/*
@description: Converts the given FHIR [Quantity](https://hl7.org/fhir/datatypes.html#Quantity) 
value to a CQL Quantity
@comment: If the given quantity has a comparator specified, a runtime error is raised. If the given quantity
has a system other than UCUM (i.e. `http://unitsofmeasure.org`) or CQL calendar units (i.e. `http://hl7.org/fhirpath/CodeSystem/calendar-units`)
an error is raised. For UCUM to calendar units, the `ToCalendarUnit` function is used.
@seealso: ToCalendarUnit
*/
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

/*
@description: Converts a UCUM definite duration unit to a CQL calendar duration
unit using conversions specified in the [quantities](https://cql.hl7.org/02-authorsguide.html#quantities) 
topic of the CQL specification.
@comment: Note that for durations above days (or weeks), the conversion is understood to be approximate
*/
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 ToString(value ObservationStatus): value.value

/*
@description: Converts the given FHIR [CodeableConcept](https://hl7.org/fhir/datatypes.html#CodeableConcept) value to a CQL Concept.
*/
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
        }

/*
@description: Converts the given FHIR [Coding](https://hl7.org/fhir/datatypes.html#Coding) value to a CQL Code.
*/
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 ToString(value EncounterStatus): value.value

define function ToString(value ServiceRequestStatus): value.value

define function ToString(value ServiceRequestIntent): value.value

define function ToString(value ProcedureStatus): value.value

/*
@description: Returns the single extension (if present) on the given resource with the specified url.
@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 fluent function ext(domainResource DomainResource, url String):
  singleton from domainResource.exts(url)

/*
@description: Returns any extensions defined on the given resource with the specified url
*/
define fluent function exts(domainResource DomainResource, url String):
  domainResource.extension E
    where E.url = url
    return E

/*
@description: Normalizes a value that is a choice of timing-valued types to an equivalent interval
@comment: Normalizes a choice type of FHIR.dateTime, FHIR.Period, FHIR.Timing, FHIR.instance, FHIR.string, FHIR.Age, or FHIR.Range types
to an equivalent interval. This selection of choice types is a superset of the majority of choice types that are used as possible
representations for timing-valued elements in FHIR, allowing this function to be used across any resource.

The input can be provided as a dateTime, Period, Timing, instant, string, Age, or Range.
The intent of this function is to provide a clear and concise mechanism to treat single
elements that have multiple possible representations as intervals so that logic doesn't have to account
for the variability. More complex calculations (such as medication request period or dispense period
calculation) need specific guidance and consideration. That guidance may make use of this function, but
the focus of this function is on single element calculations where the semantics are unambiguous.
If the input is a dateTime, the result a DateTime Interval beginning and ending on that dateTime.
If the input is a Period, the result is a DateTime Interval.
If the input is a Timing, an error is raised indicating a single interval cannot be computed from a Timing.
If the input is an instant, the result is a DateTime Interval beginning and ending on that instant.
If the input is a string, an error is raised indicating a single interval cannot be computed from a string.
If the input is an Age, the result is a DateTime Interval beginning when the patient was the given Age,
and ending immediately prior to when the patient was the given Age plus one year.
If the input is a Range, the result is a DateTime Interval beginning when the patient was the Age given
by the low end of the Range, and ending immediately prior to when the patient was the Age given by the
high end of the Range plus one year.

NOTE: Due to the
complexity of determining a single interval from a Timing or String type, this function will throw a run-time exception if it is used
with a Timing or String.
*/
define fluent function toInterval(choice Choice<FHIR.dateTime, FHIR.Period, FHIR.Timing, FHIR.instant, FHIR.string, FHIR.Age, FHIR.Range>):
  case
    when choice is FHIR.dateTime then
      Interval[FHIRHelpers.ToDateTime(choice as FHIR.dateTime), FHIRHelpers.ToDateTime(choice as FHIR.dateTime)]
    when choice is FHIR.Period then
      FHIRHelpers.ToInterval(choice as FHIR.Period)
    when choice is FHIR.instant then
      Interval[FHIRHelpers.ToDateTime(choice as FHIR.instant), FHIRHelpers.ToDateTime(choice as FHIR.instant)]
    when choice is FHIR.Age then
      Interval[FHIRHelpers.ToDate(Patient.birthDate) + FHIRHelpers.ToQuantity(choice as FHIR.Age),
        FHIRHelpers.ToDate(Patient.birthDate) + FHIRHelpers.ToQuantity(choice as FHIR.Age) + 1 year)
    when choice is FHIR.Range then
      Interval[FHIRHelpers.ToDate(Patient.birthDate) + FHIRHelpers.ToQuantity((choice as FHIR.Range).low),
        FHIRHelpers.ToDate(Patient.birthDate) + FHIRHelpers.ToQuantity((choice as FHIR.Range).high) + 1 year)
    when choice is FHIR.Timing then
      Message(null as Interval<DateTime>, true, 'NOT_IMPLEMENTED', 'Error', 'Calculation of an interval from a Timing value is not supported')
    when choice is FHIR.string then
      Message(null as Interval<DateTime>, true, 'NOT_IMPLEMENTED', 'Error', 'Calculation of an interval from a String value is not supported')
    else
      null as Interval<DateTime>
  end

/*
@description: Returns the single extension (if present) on the given element with the specified url.
@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 element with the specified url.
*/
define fluent function ext(element Element, url String):
  singleton from element.exts(url)

/*
@description: Returns any extensions defined on the given element with the specified url.
*/
define fluent function exts(element Element, url String):
  element.extension E
    where E.url = url
    return E

/*
@description: Returns conditions in the given list that either have no verification status or have a verification status of confirmed, unconfirmed, provisional, or differential
*/
define fluent function verified(conditions List<FHIR.Condition>):
  conditions C
    where C.verificationStatus is not null implies
      (C.verificationStatus ~ "confirmed"
        or C.verificationStatus ~ "unconfirmed"
        or C.verificationStatus ~ "provisional"
        or C.verificationStatus ~ "differential"
      )

/*
@description: Returns an interval representing the normalized prevalence period of a given Condition resource.
@comment: Uses the toInterval and toAbatementInterval functions to determine the widest potential interval from
onset to abatement as specified in the given Condition.
*/
define fluent function prevalenceInterval(condition Condition):
if condition.clinicalStatus ~ "active"
  or condition.clinicalStatus ~ "recurrence"
  or condition.clinicalStatus ~ "relapse" then
  Interval[start of condition.onset.toInterval(), end of condition.abatementInterval()]
else
  (end of condition.abatementInterval()) abatementDate
    return 
	  if abatementDate is null then
        Interval[start of condition.onset.toInterval(), abatementDate)
      else
        Interval[start of condition.onset.toInterval(), abatementDate]

/*
@description: Returns an interval representing the normalized Abatement of a given Condition resource.
@comment: @comment: If the abatement element of the Condition is represented as a DateTime, the result
is an interval beginning and ending on that DateTime.
If the abatement is represented as a Quantity, the quantity is expected to be a calendar-duration and is interpreted as the age of the patient. The
result is an interval from the date the patient turned that age to immediately before one year later.
If the abatement is represented as a Quantity Interval, the quantities are expected to be calendar-durations and are interpreted as an age range during
which the abatement occurred. The result is an interval from the date the patient turned the starting age of the quantity interval, and ending immediately
before one year later than the date the patient turned the ending age of the quantity interval.

NOTE: Due to the complexity of determining an interval from a String, this function will throw
a run-time exception if used with a Condition instance that has a String as the abatement value.
*/
define fluent function abatementInterval(condition Condition):
  if condition.abatement is FHIR.dateTime then
    Interval[FHIRHelpers.ToDateTime(condition.abatement as FHIR.dateTime), FHIRHelpers.ToDateTime(condition.abatement as FHIR.dateTime)]
  else if condition.abatement is FHIR.Period then
    FHIRHelpers.ToInterval(condition.abatement as FHIR.Period)
  else if condition.abatement is FHIR.string then
    Message(null as Interval<DateTime>, true, 'NOT_IMPLEMENTED', 'Error', 'Calculation of an interval from a String value is not supported')
  else if condition.abatement is FHIR.Age then
    Interval[FHIRHelpers.ToDate(Patient.birthDate) + FHIRHelpers.ToQuantity(condition.abatement as FHIR.Age),
      FHIRHelpers.ToDate(Patient.birthDate) + FHIRHelpers.ToQuantity(condition.abatement as FHIR.Age) + 1 year)
  else if condition.abatement is FHIR.Range then
    Interval[FHIRHelpers.ToDate(Patient.birthDate) + FHIRHelpers.ToQuantity((condition.abatement as FHIR.Range).low),
      FHIRHelpers.ToDate(Patient.birthDate) + FHIRHelpers.ToQuantity((condition.abatement as FHIR.Range).high) + 1 year)
  else if condition.abatement is FHIR.boolean then
    Interval[end of condition.onset.toInterval(), condition.recordedDate)
  else 
    null

/*
@description: Returns the sex element as defined for the USCore patient profile
*/
define fluent function sex(patient Patient):
  patient.ext('http://hl7.org/fhir/us/core/StructureDefinition/us-core-sex').value as FHIR.code

define fluent function ethnicity(patient Patient):
  (patient.ext('http://hl7.org/fhir/us/core/StructureDefinition/us-core-ethnicity')) E
    return {
      ombCategory: E.ext('ombCategory').value as FHIR.Coding,
      detailed: (E.exts('detailed')) d return d.value as FHIR.Coding,
      text: E.ext('text').value as FHIR.string
    }

define fluent function race(patient Patient):
  (patient.ext('http://hl7.org/fhir/us/core/StructureDefinition/us-core-race')) E
    return {
      ombCategory: (E.exts('ombCategory')) o return o.value as FHIR.Coding,
      detailed: (E.exts('detailed')) d return d.value as FHIR.Coding,
      text: E.ext('text').value as FHIR.string
    }