define "Initial Population 1":
  AgeInYearsAt(date from start of "Intake Period") >= 6
    and AgeInYearsAt(date from 
      end of "Intake Period"
    ) <= 12
    and exists "Qualifying Encounter"
    and "First ADHD Medication Prescribed During Intake Period" is not null
    and not exists "Inpatient Stay with Qualifying Diagnosis During Initiation Phase"

define "Denominator 1":
  "Initial Population 1"

define "Denominator Exclusions":
  Hospice."Has Hospice Services"
    or exists "Narcolepsy Exclusion"

define "Numerator 1":
  exists "Encounter During Initiation Phase"

define "Initial Population 2":
  AgeInYearsAt(date from start of "Intake Period") >= 6
    and AgeInYearsAt(date from 
      end of "Intake Period"
    ) <= 12
    and exists "Qualifying Encounter"
    and "First ADHD Medication Prescribed During Intake Period" is not null
    and "Has ADHD Cumulative Medication Duration Greater Than or Equal to 210 Days"
    and not exists "Inpatient Stay with Qualifying Diagnosis During Continuation and Maintenance Phase"

define "Denominator 2":
  "Initial Population 2"

define "Denominator Exclusions":
  Hospice."Has Hospice Services"
    or exists "Narcolepsy Exclusion"

define "Numerator 2":
  exists "Encounter During Initiation Phase"
    and ( "Two or More Encounters 31 to 300 Days into Continuation and Maintenance Phase"
        or ( exists "Encounter 31 to 300 Days into Continuation and Maintenance Phase" Encounter1
            with "Virtual Encounter 31 to 300 Days into Continuation and Maintenance Phase" Encounter2
              such that Encounter1 is not null
                and Encounter2 is not null
                and Encounter1 !~ Encounter2
        )
    )

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 "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 "March 1 of Year Prior to Measurement Period":
  DateTime((year from start of "Measurement Period" - 1), 3, 1, 0, 0, 0, 0, 0)

define "Last Calendar Day of February of Measurement Period":
  ( DateTime(year from start of "Measurement Period", 3, 1, 23, 59, 59, 0, 0) ) - 1 day

define "Intake Period":
  Interval["March 1 of Year Prior to Measurement Period", "Last Calendar Day of February of Measurement Period"]

define "ADHD Medication Prescribed During Intake Period and Not Previously on ADHD Medication":
  ( ( ( ( [MedicationRequest: "Atomoxetine"]
      union [MedicationRequest: "Clonidine"]
      union [MedicationRequest: "Dexmethylphenidate"]
      union [MedicationRequest: "Dextroamphetamine"]
      union [MedicationRequest: "Lisdexamfetamine"]
      union [MedicationRequest: "methamphetamine hydrochloride 5 MG Oral Tablet"]
      union [MedicationRequest: "Methylphenidate"]
      union [MedicationRequest: "Guanfacine Medications"]
      union [MedicationRequest: "Viloxazine"]
  ).isMedicationOrder ( ) ) ADHDMedications
    where ADHDMedications.medicationRequestPeriod ( ) starts during "Intake Period" ) ADHDMedicationOrder
    without ( ( [MedicationRequest: "Atomoxetine"]
        union [MedicationRequest: "Clonidine"]
        union [MedicationRequest: "Dexmethylphenidate"]
        union [MedicationRequest: "Dextroamphetamine"]
        union [MedicationRequest: "Lisdexamfetamine"]
        union [MedicationRequest: "methamphetamine hydrochloride 5 MG Oral Tablet"]
        union [MedicationRequest: "Methylphenidate"]
        union [MedicationRequest: "Guanfacine Medications"]
        union [MedicationRequest: "Viloxazine"]
    ).isMedicationActive ( ) ) ActiveADHDMedication
      such that ActiveADHDMedication.medicationRequestPeriod ( ) overlaps Interval[date from start of ADHDMedicationOrder.medicationRequestPeriod ( ) - 120 days, date from start of ADHDMedicationOrder.medicationRequestPeriod ( ) ) ) QualifyingMed
    return all {
      startDate: start of QualifyingMed.medicationRequestPeriod ( )
    }
    sort by startDate asc

define "First ADHD Medication Prescribed During Intake Period":
  First("ADHD Medication Prescribed During Intake Period and Not Previously on ADHD Medication".startDate)

/*Index Prescription Start Date (IPSD)*/


define "IPSD":
  "First ADHD Medication Prescribed During Intake Period"

define "Qualifying Encounter":
  ( ( [Encounter: "Office Visit"]
      union [Encounter: "Home Healthcare Services"]
      union [Encounter: "Preventive Care, Established Office Visit, 0 to 17"]
      union [Encounter: "Preventive Care Services, Initial Office Visit, 0 to 17"]
  ).isEncounterPerformed ( ) ) ValidEncounters
    where CQMCommon."ToDateInterval" ( ValidEncounters.period ) during day of Interval["IPSD" - 6 months, "IPSD"]

define "ADHD Medications Taken on IPSD or During Continuation and Maintenance Phase":
  ( ( ( ( ( ( [MedicationRequest: "Atomoxetine"] ).isMedicationOrder ( ) ) AtomoxetineMed
          return all {
            period: AtomoxetineMed.medicationRequestPeriod ( ),
            periodStart: start of AtomoxetineMed.medicationRequestPeriod ( )
          }
          sort by periodStart
      ).period
    ).rolloutIntervals ( )
  )
    union ( ( ( ( ( [MedicationRequest: "Clonidine"] ).isMedicationOrder ( ) ) ClonidineMed
            return all {
              period: ClonidineMed.medicationRequestPeriod ( ),
              periodStart: start of ClonidineMed.medicationRequestPeriod ( )
            }
            sort by periodStart
        ).period
      ).rolloutIntervals ( )
    )
    union ( ( ( ( ( [MedicationRequest: "Dexmethylphenidate"] ).isMedicationOrder ( ) ) DexmethylphenidateMed
            return all {
              period: DexmethylphenidateMed.medicationRequestPeriod ( ),
              periodStart: start of DexmethylphenidateMed.medicationRequestPeriod ( )
            }
            sort by periodStart
        ).period
      ).rolloutIntervals ( )
    )
    union ( ( ( ( ( [MedicationRequest: "Dextroamphetamine"] ).isMedicationOrder ( ) ) DextroamphetamineMed
            return all {
              period: DextroamphetamineMed.medicationRequestPeriod ( ),
              periodStart: start of DextroamphetamineMed.medicationRequestPeriod ( )
            }
            sort by periodStart
        ).period
      ).rolloutIntervals ( )
    )
    union ( ( ( ( ( [MedicationRequest: "Lisdexamfetamine"] ).isMedicationOrder ( ) ) LisdexamfetamineMed
            return all {
              period: LisdexamfetamineMed.medicationRequestPeriod ( ),
              periodStart: start of LisdexamfetamineMed.medicationRequestPeriod ( )
            }
            sort by periodStart
        ).period
      ).rolloutIntervals ( )
    )
    union ( ( ( ( ( [MedicationRequest: "Methylphenidate"] ).isMedicationOrder ( ) ) MethylphenidateMed
            return all {
              period: MethylphenidateMed.medicationRequestPeriod ( ),
              periodStart: start of MethylphenidateMed.medicationRequestPeriod ( )
            }
            sort by periodStart
        ).period
      ).rolloutIntervals ( )
    )
    union ( ( ( ( ( [MedicationRequest: "Guanfacine Medications"] ).isMedicationOrder ( ) ) GuanfacineMed
            return all {
              period: GuanfacineMed.medicationRequestPeriod ( ),
              periodStart: start of GuanfacineMed.medicationRequestPeriod ( )
            }
            sort by periodStart
        ).period
      ).rolloutIntervals ( )
    )
    union ( ( ( ( ( [MedicationRequest: "methamphetamine hydrochloride 5 MG Oral Tablet"] ).isMedicationOrder ( ) ) MethamphetamineMed
            return all {
              period: MethamphetamineMed.medicationRequestPeriod ( ),
              periodStart: start of MethamphetamineMed.medicationRequestPeriod ( )
            }
            sort by periodStart
        ).period
      ).rolloutIntervals ( )
    )
    union ( ( ( ( ( [MedicationRequest: "Viloxazine"] ).isMedicationOrder ( ) ) ViloxazineMed
            return all {
              period: ViloxazineMed.medicationRequestPeriod ( ),
              periodStart: start of ViloxazineMed.medicationRequestPeriod ( )
            }
            sort by periodStart
        ).period
      ).rolloutIntervals ( )
    ) ) ADHDMedication
    let IPSDAndContinuationMaintenancePhase: Interval["IPSD", "IPSD" + 300 days]
    return all ADHDMedication
      intersect IPSDAndContinuationMaintenancePhase

define "ADHD Cumulative Medication Duration":
  ( "ADHD Medications Taken on IPSD or During Continuation and Maintenance Phase" ).cumulativeDuration ( )

define "Has ADHD Cumulative Medication Duration Greater Than or Equal to 210 Days":
  "ADHD Cumulative Medication Duration" >= 210

define "Inpatient Stay with Qualifying Diagnosis":
  ( ( [Encounter: "Encounter Inpatient"] ).isEncounterPerformed ( ) ) InpatientStay
    where InpatientStay.hasPrincipalDiagnosisOf ( "Mental Behavioral and Neurodevelopmental Disorders" )

define "Inpatient Stay with Qualifying Diagnosis During Continuation and Maintenance Phase":
  "Inpatient Stay with Qualifying Diagnosis" InpatientStay
    where CQMCommon."ToDateInterval" ( InpatientStay.period ) starts 300 days or less after day of "IPSD"

define "Initial Population 2":
  AgeInYearsAt(date from start of "Intake Period") >= 6
    and AgeInYearsAt(date from 
      end of "Intake Period"
    ) <= 12
    and exists "Qualifying Encounter"
    and "First ADHD Medication Prescribed During Intake Period" is not null
    and "Has ADHD Cumulative Medication Duration Greater Than or Equal to 210 Days"
    and not exists "Inpatient Stay with Qualifying Diagnosis During Continuation and Maintenance Phase"

define "Denominator 2":
  "Initial Population 2"

define "Qualifying Numerator Encounter":
  [Encounter: "Office Visit"]
    union [Encounter: "Preventive Care Services Group Counseling"]
    union [Encounter: "Behavioral Health Follow up Visit"]
    union [Encounter: "Preventive Care Services Individual Counseling"]
    union ( [Encounter: "Psychotherapy and Pharmacologic Management"] PsychPharmManagement
        where exists ( PsychPharmManagement.location Location
            where CQMCommon."GetLocation" ( Location.location ).type in "Ambulatory"
        )
    )
    union [Encounter: "Outpatient Consultation"]
    union [Encounter: "Home Healthcare Services"]
    union [Encounter: "Preventive Care Services, Initial Office Visit, 0 to 17"]
    union [Encounter: "Preventive Care, Established Office Visit, 0 to 17"]
    union [Encounter: "Psych Visit Diagnostic Evaluation"]
    union [Encounter: "Psych Visit Psychotherapy"]
    union [Encounter: "Telephone Visits"]

define "Encounter During Initiation Phase":
  ( "Qualifying Numerator Encounter".isEncounterPerformed ( ) ) ValidNumeratorEncounter
    where CQMCommon."ToDateInterval" ( ValidNumeratorEncounter.period ) starts 30 days or less after day of "IPSD"

define "Numerator 1":
  exists "Encounter During Initiation Phase"

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

define "Encounter 31 to 300 Days into Continuation and Maintenance Phase":
  ( "Qualifying Numerator Encounter".isEncounterPerformed ( ) ) ValidNumeratorEncounter
    where CQMCommon."ToDateInterval" ( ValidNumeratorEncounter.period ) starts during day of Interval["IPSD" + 31 days, "IPSD" + 300 days]
    return date from start of ValidNumeratorEncounter.period

define "Two or More Encounters 31 to 300 Days into Continuation and Maintenance Phase":
  Count("Encounter 31 to 300 Days into Continuation and Maintenance Phase") >= 2

define "Virtual Encounter 31 to 300 Days into Continuation and Maintenance Phase":
  ( ( [Encounter: "Virtual Encounter"] ).isEncounterPerformed ( ) ) VirtualEnc
    where CQMCommon."ToDateInterval" ( VirtualEnc.period ) starts during day of Interval["IPSD" + 31 days, "IPSD" + 300 days]
    return date from start of VirtualEnc.period

define "Numerator 2":
  exists "Encounter During Initiation Phase"
    and ( "Two or More Encounters 31 to 300 Days into Continuation and Maintenance Phase"
        or ( exists "Encounter 31 to 300 Days into Continuation and Maintenance Phase" Encounter1
            with "Virtual Encounter 31 to 300 Days into Continuation and Maintenance Phase" Encounter2
              such that Encounter1 is not null
                and Encounter2 is not null
                and Encounter1 !~ Encounter2
        )
    )

define "Inpatient Stay with Qualifying Diagnosis During Initiation Phase":
  "Inpatient Stay with Qualifying Diagnosis" InpatientStay
    where CQMCommon."ToDateInterval" ( InpatientStay.period ) starts 30 days or less after day of "IPSD"

define "Initial Population 1":
  AgeInYearsAt(date from start of "Intake Period") >= 6
    and AgeInYearsAt(date from 
      end of "Intake Period"
    ) <= 12
    and exists "Qualifying Encounter"
    and "First ADHD Medication Prescribed During Intake Period" is not null
    and not exists "Inpatient Stay with Qualifying Diagnosis During Initiation Phase"

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

define "Narcolepsy Exclusion":
  ( ( [ConditionProblemsHealthConcerns: "Narcolepsy"]
      union [ConditionEncounterDiagnosis: "Narcolepsy"]
  ).verified ( ) ) NarcolepsyDx
    where NarcolepsyDx.onset.toInterval ( ) starts on or before end of "Measurement Period"

define "Denominator Exclusions":
  Hospice."Has Hospice Services"
    or exists "Narcolepsy Exclusion"

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

define "Denominator 1":
  "Initial Population 1"

/*
Calculates the Medication Period for a single MedicationRequest.
MedicationRequest instances provided to this function are expected
to conform to the [MMEMedicationRequest](http://build.fhir.org/ig/cqframework/opioid-mme-r4/StructureDefinition-mmemedicationrequest.html)
profile, which expects:
* 1 and only 1 dosageInstruction, multiple dosageInstruction elements will result in an error
* 1 and only 1 doseAndRate, multiple doseAndRate elements will result in an error
* 1 timing with 1 repeat, missing timing or repeat elements will result in a null
* frequency, frequencyMax, defaulting to 1
* period, periodUnit, defaulting to 1 'd'
* timeOfDay
* doseQuantity or doseRange, missing doseQuantity and doseRange will result in a null
Note that MedicationRequest status is not considered by this calculation, as the
list of MedicationRequest instances provided to this function should already have
considered appropriate statuses, depending on the use case, typically `completed`.

NOTE: Updated return to use "date from end of boundsPeriod" to ensure result is Interval<Date>
*/
define fluent function medicationRequestPeriod(Request MedicationRequest):
  Request R
    let
      dosage: singleton from R.dosageInstruction,
      doseAndRate: singleton from dosage.doseAndRate,
      timing: dosage.timing,
      frequency: Coalesce(timing.repeat.frequencyMax, timing.repeat.frequency),
      period: Quantity(timing.repeat.period, timing.repeat.periodUnit),
      doseRange: doseAndRate.dose as FHIR.Range,
      doseQuantity: doseAndRate.dose as FHIR.SimpleQuantity,

      dose: Coalesce(end of doseRange, doseQuantity),
      dosesPerDay: Coalesce(ToDaily(frequency, period), Count(timing.repeat.timeOfDay), 1.0),
      boundsPeriod: timing.repeat.bounds as Period,
      // TODO: this isn't working as expected, convert results in null
      //daysSupply: (convert(R.dispenseRequest.expectedSupplyDuration) to days).value,
      daysSupply: (R.dispenseRequest.expectedSupplyDuration).value,
      quantity: R.dispenseRequest.quantity,
      refills: Coalesce(R.dispenseRequest.numberOfRepeatsAllowed, 0),
      startDate:
        Coalesce(
          date from start of boundsPeriod,
          date from R.authoredOn,
          date from start of R.dispenseRequest.validityPeriod
        ),
      totalDaysSupplied: Coalesce(daysSupply, quantity.value / (dose.value * dosesPerDay)) * (1 + refills)
    return
      if startDate is not null and totalDaysSupplied is not null then
        Interval[startDate, startDate + Quantity(totalDaysSupplied - 1, 'day') ]
      else if startDate is not null and boundsPeriod."end" is not null then
        Interval[startDate, date from end of boundsPeriod]
      else
        null

/**********************************************************************/
/* Functions in this region are copied from opioid-mme-r4             */
/**********************************************************************/

define function Quantity(value Decimal, unit String):
  if value is not null then
    System.Quantity { value: value, unit: unit }
  else
    null

/*
 Goal is to get to number of days
 Two broad approaches to the calculation:
  1) Based on supply and frequency, calculate the number of expected days the medication will cover/has covered
  2) Based on relevant period, determine a covered interval and calculate the length of that interval in days

This topic covers several use cases and illustrates how to calculate Cumulative
Medication Duration for each type of medication resource using the supply and
frequency approach.
*/

/*
  For the first approach, we need to get from frequency to a frequency/day
  So we define ToDaily
*/

/*
  Calculates daily frequency given frequency within a period
*/
define function ToDaily(frequency System.Integer, period System.Quantity):
  case period.unit
    when 'h' then frequency * (24.0 / period.value)
    when 'min' then frequency * (24.0 / period.value) * 60
    when 's' then frequency * (24.0 / period.value) * 60 * 60
    when 'd' then frequency * (24.0 / period.value) / 24
    when 'wk' then frequency * (24.0 / period.value) / (24 * 7)
    when 'mo' then frequency * (24.0 / period.value) / (24 * 30) /* assuming 30 days in month */
    when 'a' then frequency * (24.0 / period.value) / (24 * 365) /* assuming 365 days in year */
    when 'hour' then frequency * (24.0 / period.value)
    when 'minute' then frequency * (24.0 / period.value) * 60
    when 'second' then frequency * (24.0 / period.value) * 60 * 60
    when 'day' then frequency * (24.0 / period.value) / 24
    when 'week' then frequency * (24.0 / period.value) / (24 * 7)
    when 'month' then frequency * (24.0 / period.value) / (24 * 30) /* assuming 30 days in month */
    when 'year' then frequency * (24.0 / period.value) / (24 * 365) /* assuming 365 days in year */
    when 'hours' then frequency * (24.0 / period.value)
    when 'minutes' then frequency * (24.0 / period.value) * 60
    when 'seconds' then frequency * (24.0 / period.value) * 60 * 60
    when 'days' then frequency * (24.0 / period.value) / 24
    when 'weeks' then frequency * (24.0 / period.value) / (24 * 7)
    when 'months' then frequency * (24.0 / period.value) / (24 * 30) /* assuming 30 days in month */
    when 'years' then frequency * (24.0 / period.value) / (24 * 365) /* assuming 365 days in year */
    else Message(null, true, 'CMDLogic.ToDaily.UnknownUnit', ErrorLevel, 'Unknown unit ' & period.unit)
  end

/*
Now that we have functions for determining the medication period for individual
prescriptions, administrations, and dispenses, we can combine those using
an overall cumulative medication duration calculation.

There are two broad approaches to calculating cumulative duration, one that _collapses_
overlapping intervals so that calculations are not duplicated, and one that _rolls out_
overlapping intervals so that the durations are laid end-to-end.

First, we define a function that simply calculates CumulativeDuration of a set of
intervals:

NOTE: Updated argument to List<Interval<Date>> instead of List<Interval<DateTime>>
*/
define fluent function cumulativeDuration(Intervals List<Interval<Date>>):
   if Intervals is not null then ( Sum((collapse Intervals per day)X
        return all(difference in days between start of X and 
          end of X
        )+ 1
    )
  ) 
    else null

/*
Next, we define a function that rolls out intervals:

NOTE: Updated argument to List<Interval<Date>> instead of List<Interval<DateTime>>
*/
define fluent function rolloutIntervals(intervals List<Interval<Date>>):
 intervals I aggregate all R starting ( null as List<Interval<Date>>): R
    union ( { I X
        let S: Max({ 
          end of Last(R)+ 1 day, start of X }
        ),
        E: S + Quantity(Coalesce(duration in days of X, 0), 'day')
        return Interval[S, E]}
    )

/*
@description: Returns an interval of date values extracted from the input interval of date-time values
@comment: This function returns an interval constructed using the `date from` extractor on the start
and end values of the input date-time interval. Note that using a precision specifier such as `day of`
as part of a timing phrase is preferred to communicate intent to perform day-level comparison, as well
as for general readability.
*/
define function "ToDateInterval"(period Interval<DateTime>):
  Interval[date from start of period, date from end of period]

/*
 @description: Returns the condition that is specified as the principal diagnosis for the encounter and has a code in the given valueSet.
 @comment: See the QICore 6 Authoring Patterns discussion on [Principal Diagnosis and Present on Admission](https://github.com/cqframework/CQL-Formatting-and-Usage-Wiki/wiki/Authoring-Patterns-QICore-v6.0.0#conditions-present-on-admission-and-principal-diagnoses) for more information
 */
 define fluent function hasPrincipalDiagnosisOf(encounter Encounter, valueSet System.ValueSet):
   (encounter.principalDiagnosis()) PD
     return PD.diagnosis in valueSet
       or PD.diagnosis.getCondition().code in valueSet

/*
@description: Returns the claim diagnosis element that is specified as the principal diagnosis for the encounter
 @comment: See the QICore 6 Authoring Patterns discussion on [Principal Diagnosis and Present on Admission](https://github.com/cqframework/CQL-Formatting-and-Usage-Wiki/wiki/Authoring-Patterns-QICore-v6.0.0#conditions-present-on-admission-and-principal-diagnoses) for more information
*/
define fluent function principalDiagnosis(encounter Encounter):
singleton from (
     (encounter.claimDiagnosis()) CD
       where CD.type.includesCode("Principal Diagnosis")
   )

/*
@description: Returns the claim diagnosis elements for the given encounter
@comment: See the QICore 6 Authoring Patterns discussion on [Principal Diagnosis and Present on Admission](https://github.com/cqframework/CQL-Formatting-and-Usage-Wiki/wiki/Authoring-Patterns-QICore-v6.0.0#conditions-present-on-admission-and-principal-diagnoses) for more information
*/
define fluent function claimDiagnosis(encounter Encounter):
  encounter E
    let 
      claim: ([Claim] C where C.status = 'active' and C.use = 'claim' and exists (C.item I where I.encounter.references(E))),
      claimItem: (claim.item I where I.encounter.references(E))
    return claim.diagnosis D where D.sequence in claimItem.diagnosisSequence

/*
@description: Returns the Condition resource for the given reference
*/
define fluent function getCondition(reference Reference):
  singleton from (([ConditionEncounterDiagnosis] union [ConditionProblemsHealthConcerns]) C where reference.references(C.id))

/*
@description: Returns the Location resource specified by the given reference
@deprecated: This function is deprecated. Use the fluent function `getLocation()` instead.
*/
define function "GetLocation"(reference Reference):
  singleton from (
    [Location] L where reference.references(L)
  )

define function ToString(value string): value.value

define function ToString(value uri): value.value

define function ToDate(value date): value.value

define function ToString(value EncounterStatus): 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 ToString(value MedicationRequestStatus): value.value

define function ToString(value MedicationRequestIntent): 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 ToDecimal(value decimal): value.value

define function ToString(value UnitsOfTime): value.value

/*
@description: Converts the given FHIR [Range](https://hl7.org/fhir/datatypes.html#Range) value to a CQL Interval of Quantity
*/
define function ToInterval(range FHIR.Range):
    if range is null then
        null
    else
        Interval[ToQuantity(range.low), ToQuantity(range.high)]

/*
@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 ToInteger(value integer): value.value

define function ToDateTime(value dateTime): value.value

define function ToString(value ClaimStatus): value.value

define function ToString(value Use): value.value

define function ToString(value ObservationStatus): value.value

define function ToDateTime(value instant): 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: 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, '/'))

/*
@description: Returns true if the given code is in the given codeList
@comment: Returns true if the `code` is equivalent to any of the codes in the given `codeList`, false otherwise.
*/
define fluent function includesCode(codeList List<CodeableConcept>, code Concept):
  exists (codeList C where C ~ code)

/*
@description: Returns true if the given reference is to the given resourceId
@comment: Returns true if the `resourceId` parameter 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, resourceId String):
  resourceId = Last(Split(reference.reference, '/'))

/*
@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: 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 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

//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'

//Medication, Order
define fluent function isMedicationOrder(MedicationRequest List<FHIR.MedicationRequest>):
  MedicationRequest M
    where M.status in { 'active', 'completed' }
    and M.intent in {'order', 'original-order', 'reflex-order', 'filler-order', 'instance-order'}

//Medication, Active
define fluent function isMedicationActive(MedicationRequest List<FHIR.MedicationRequest>):
  MedicationRequest M
    where M.status = 'active'
      and M.intent in {'order', 'original-order', 'reflex-order', 'filler-order', 'instance-order'}

//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'

// TODO: Deprecate because this is now in FHIRCommon
//Condition
/*
@description: Returns conditions in the given list that either have no verification status or have a verification status of confirmed, unconfirmed, provisional, or differential
@deprecated: Use the USCoreCommon verified function insteada
*/
define fluent function verified(conditions List<Choice<ConditionProblemsHealthConcerns, ConditionEncounterDiagnosis>>):
  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 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
    }