define "Initial Population":
  "Qualifying Encounters During Measurement Period"
    union "Encounters with Patient Hospital Locations"

/*
@description: Returns the Location resource specified by the given reference.
*/
define fluent function getLocation(reference Reference):
  singleton from (
    [Location] L where reference.references(L)
  )

// ----------------------------------------------------------------------
// Core encounter logic
// ----------------------------------------------------------------------

// Encounters with NHSN class codes (IMP, ACUTE, NONAC, SS)





define "Encounters with NHSN Inpatient Class":
  [Encounter] Enc
    where Enc.class ~ USQualityCoreCommon."inpatient encounter"
      or Enc.class ~ USQualityCoreCommon."inpatient acute"
      or Enc.class ~ USQualityCoreCommon."inpatient non-acute"
      or Enc.class ~ USQualityCoreCommon."short stay"

define "Qualifying Encounters During Measurement Period":
  ( [Encounter: "Encounter Inpatient"]
    union [Encounter: "Emergency Department Visit"]
    union [Encounter: "Observation Services"]
    union "Encounters with NHSN Inpatient Class"
    union [Encounter: class ~ "emergency"]
    union [Encounter: class ~ "observation encounter"] ) QualifyingEncounters
    where QualifyingEncounters.status in { 'in-progress', 'finished', 'triaged', 'onleave', 'entered-in-error' }
      and QualifyingEncounters.period overlaps "Measurement Period"

define "Encounters":
  [Encounter]

define "Encounters with Patient Hospital Locations":
  "Encounters" Ens
    where exists ( Ens.location EncounterLocation
        where EncounterLocation.period overlaps Ens.period
          and EncounterLocation.location.getLocation ( ).type in "Inpatient, Emergency, and Observation Locations"
    )
      and Ens.status in { 'in-progress', 'finished', 'triaged', 'onleave', 'entered-in-error' }
      and Ens.period overlaps "Measurement Period"

define "Initial Population":
  "Qualifying Encounters During Measurement Period"
    union "Encounters with Patient Hospital Locations"

// Coverage SDE – tuples of Coverage data


define "SDE Coverage":
  [Coverage] Coverages
    where exists ( "Initial Population" IP
        where Coverages.period overlaps IP.period
    )
    return {
      id: Coverages.id,
      meta: Coverages.meta,
      status: Coverages.status,
      type: Coverages.type,
      policyHolder: Coverages.policyHolder,
      subscriber: Coverages.subscriber,
      subscriberId: Coverages.subscriberId,
      beneficiary: Coverages.beneficiary,
      dependent: Coverages.dependent,
      relationship: Coverages.relationship,
      period: Coverages.period,
      payor: Coverages.payor,
      class: Coverages.class,
      order: Coverages.order,
      network: Coverages.network,
      subrogation: Coverages.subrogation,
      contract: Coverages.contract
    }

// Encounter SDEs


define "SDE Encounter":
  "Encounters" Ens
    where not "CheckIP"(Ens)
      and exists ( "Initial Population" IP
          where Ens.period overlaps IP.period
      )
    return {
      id: Ens.id,
      meta: Ens.meta,
      identifier: Ens.identifier,
      status: Ens.status,
      statusHistory: Ens.statusHistory,
      class: Ens.class,
      classHistory: Ens.classHistory,
      type: Ens.type,
      serviceType: Ens.serviceType,
      priority: Ens.priority,
      subject: Ens.subject,
      period: Ens.period,
      length: Ens.length,
      reasonCode: Ens.reasonCode,
      reasonReference: Ens.reasonReference,
      diagnosis: Ens.diagnosis,
      account: Ens.account,
      hospitalization: Ens.hospitalization,
      location: Ens.location,
      partOf: Ens.partOf
    }

// Procedure SDE


define "SDE Procedure":
  [Procedure] Procedures
    where exists ( "Initial Population" IP
        where "Normalize Interval"(Procedures.performed) overlaps IP.period
    )
    return {
      id: Procedures.id,
      meta: Procedures.meta,
      extension: Procedures.extension,
      basedOn: Procedures.basedOn,
      partOf: Procedures.partOf,
      status: Procedures.status,
      category: Procedures.category,
      code: Procedures.code,
      subject: Procedures.subject,
      encounter: Procedures.encounter,
      performed: Procedures.performed,
      location: Procedures.location,
      reasonCode: Procedures.reasonCode,
      reasonReference: Procedures.reasonReference,
      bodySite: Procedures.bodySite
    }

// Device SDE – tuples of Device data


define "SDE Device":
  [Device] Devices
    where exists ( "Initial Population" )
    return {
      id: Devices.id,
      meta: Devices.meta,
      extension: Devices.extension,
      status: Devices.status,
      expirationDate: Devices.expirationDate,
      lotNumber: Devices.lotNumber,
      serialNumber: Devices.serialNumber,
      modelNumber: Devices.modelNumber,
      partNumber: Devices.partNumber,
      type: Devices.type,
      patient: Devices.patient,
      parent: Devices.parent
    }

define "SDE Observation Vital Signs Category":
  [USCore.VitalSignsProfile] Obs
    where exists ( "Initial Population" IP
        where "Normalize Interval"(Obs.effective) overlaps IP.period
    )
    return {
      id: Obs.id,
      meta: Obs.meta,
      extension: Obs.extension,
      partOf: Obs.partOf,
      status: Obs.status,
      category: Obs.category,
      code: Obs.code,
      subject: Obs.subject,
      encounter: Obs.encounter,
      effective: Obs.effective,
      issued: Obs.issued,
      value: Obs.value,
      dataAbsentReason: Obs.dataAbsentReason,
      interpretation: Obs.interpretation,
      bodySite: Obs.bodySite,
      method: Obs.method,
      specimen: Obs.specimen,
      referenceRange: Obs.referenceRange,
      hasMember: Obs.hasMember,
      derivedFrom: Obs.derivedFrom,
      component: Obs.component
    }

define "SDE DiagnosticReport Others":
  [DiagnosticReportNote] dr
    where not ( exists ( dr.category Category
          where Category ~ "Radiology"
      )
        or exists ( dr.category Category
            where Category ~ "Pathology"
        )
        or exists ( dr.category Category
            where Category ~ "Cardiology"
        )
    )
      and exists ( "Initial Population" IP
          where "Normalize Interval"(dr.effective) overlaps IP.period
      )
    return {
      id: dr.id,
      meta: dr.meta,
      extension: dr.extension,
      basedOn: dr.basedOn,
      status: dr.status,
      category: dr.category,
      code: dr.code,
      subject: dr.subject,
      encounter: dr.encounter,
      effective: dr.effective,
      issued: dr.issued,
      specimen: dr.specimen,
      result: dr.result,
      conclusion: dr.conclusion,
      conclusionCode: dr.conclusionCode
    }

define "SDE Specimens":
  [USCore.SpecimenProfile] sp
    where exists ( "Initial Population" IP
        where "Normalize Interval"(sp.collection.collected) overlaps IP.period
    )
    return {
      id: sp.id,
      type: sp.type
    }

define "SDE Medication Administration Not Done":
  [MedicationAdministrationNotDone] MedAdministrations
    where exists ( "Initial Population" IP
        where "Normalize Interval"(MedAdministrations.effective) overlaps IP.period
    )
    return {
      id: MedAdministrations.id,
      meta: MedAdministrations.meta,
      instantiates: MedAdministrations.instantiates,
      partOf: MedAdministrations.partOf,
      status: MedAdministrations.status,
      statusReason: MedAdministrations.statusReason,
      category: MedAdministrations.category,
      medication: MedAdministrations.medication,
      subject: MedAdministrations.subject,
      context: MedAdministrations.context,
      supportingInformation: MedAdministrations.supportingInformation,
      effective: MedAdministrations.effective,
      performer: MedAdministrations.performer,
      reasonCode: MedAdministrations.reasonCode,
      reasonReference: MedAdministrations.reasonReference,
      request: MedAdministrations.request,
      device: MedAdministrations.device,
      note: MedAdministrations.note,
      dosage: MedAdministrations.dosage
    }

// SDE Medication Not Requested - negation requests (doNotPerform is true)


define "SDE Medication Not Requested":
  [MedicationNotRequested] MedNotRequests
    where exists ( "Initial Population" IP
        where MedNotRequests.authoredOn during IP.period
    )
    return {
      id: MedNotRequests.id,
      meta: MedNotRequests.meta,
      status: MedNotRequests.status,
      statusReason: MedNotRequests.statusReason,
      intent: MedNotRequests.intent,
      category: MedNotRequests.category,
      priority: MedNotRequests.priority,
      doNotPerform: MedNotRequests.doNotPerform,
      reported: MedNotRequests.reported,
      medication: MedNotRequests.medication,
      subject: MedNotRequests.subject,
      encounter: MedNotRequests.encounter,
      authoredOn: MedNotRequests.authoredOn,
      requester: MedNotRequests.requester,
      recorder: MedNotRequests.recorder,
      reasonCode: MedNotRequests.reasonCode,
      reasonReference: MedNotRequests.reasonReference,
      instantiatesCanonical: MedNotRequests.instantiatesCanonical,
      instantiatesUri: MedNotRequests.instantiatesUri,
      courseOfTherapyType: MedNotRequests.courseOfTherapyType,
      dosageInstruction: MedNotRequests.dosageInstruction
    }

// ServiceRequest SDE - regular requests (doNotPerform is false or absent)


define "SDE Service Request Base":
  [ServiceRequest] ServiceRequests
    where exists ( "Initial Population" IP
        where ServiceRequests.authoredOn during IP.period
    )
    return {
      id: ServiceRequests.id,
      meta: ServiceRequests.meta,
      instantiatesCanonical: ServiceRequests.instantiatesCanonical,
      instantiatesUri: ServiceRequests.instantiatesUri,
      basedOn: ServiceRequests.basedOn,
      replaces: ServiceRequests.replaces,
      requisition: ServiceRequests.requisition,
      status: ServiceRequests.status,
      intent: ServiceRequests.intent,
      category: ServiceRequests.category,
      priority: ServiceRequests.priority,
      //doNotPerform: ServiceRequests.doNotPerform,
      
      code: ServiceRequests.code,
      orderDetail: ServiceRequests.orderDetail,
      quantity: ServiceRequests.quantity,
      subject: ServiceRequests.subject,
      encounter: ServiceRequests.encounter,
      occurrence: ServiceRequests.occurrence,
      asNeeded: ServiceRequests.asNeeded,
      authoredOn: ServiceRequests.authoredOn,
      requester: ServiceRequests.requester,
      performerType: ServiceRequests.performerType,
      performer: ServiceRequests.performer,
      locationCode: ServiceRequests.locationCode,
      reasonCode: ServiceRequests.reasonCode,
      reasonReference: ServiceRequests.reasonReference,
      insurance: ServiceRequests.insurance,
      bodySite: ServiceRequests.bodySite,
      note: ServiceRequests.note,
      patientInstruction: ServiceRequests.patientInstruction
    }

// ServiceNotRequested SDE - negation requests (doNotPerform is true)


define "SDE Service Not Requested":
  [ServiceNotRequested] ServiceNotReqs
    where exists ( "Initial Population" IP
        where ServiceNotReqs.authoredOn during IP.period
    )
    return {
      id: ServiceNotReqs.id,
      meta: ServiceNotReqs.meta,
      instantiatesCanonical: ServiceNotReqs.instantiatesCanonical,
      instantiatesUri: ServiceNotReqs.instantiatesUri,
      basedOn: ServiceNotReqs.basedOn,
      replaces: ServiceNotReqs.replaces,
      requisition: ServiceNotReqs.requisition,
      status: ServiceNotReqs.status,
      intent: ServiceNotReqs.intent,
      category: ServiceNotReqs.category,
      priority: ServiceNotReqs.priority,
      doNotPerform: ServiceNotReqs.doNotPerform,
      code: ServiceNotReqs.code,
      orderDetail: ServiceNotReqs.orderDetail,
      quantity: ServiceNotReqs.quantity,
      subject: ServiceNotReqs.subject,
      encounter: ServiceNotReqs.encounter,
      occurrence: ServiceNotReqs.occurrence,
      asNeeded: ServiceNotReqs.asNeeded,
      authoredOn: ServiceNotReqs.authoredOn,
      requester: ServiceNotReqs.requester,
      performerType: ServiceNotReqs.performerType,
      performer: ServiceNotReqs.performer,
      locationCode: ServiceNotReqs.locationCode,
      reasonCode: ServiceNotReqs.reasonCode,
      reasonReference: ServiceNotReqs.reasonReference,
      insurance: ServiceNotReqs.insurance,
      bodySite: ServiceNotReqs.bodySite,
      note: ServiceNotReqs.note,
      patientInstruction: ServiceNotReqs.patientInstruction
    }

// Combined SDE for all Service Requests (both regular and negation)


define "SDE Service Request":
  "SDE Service Request Base"
    union "SDE Service Not Requested"

// Survey is fixed category code in ObservationScreeningAssessment profile in QI-Core    


define "SDE Observation Survey":
  [ObservationScreeningAssessment] Obs
    where exists ( "Initial Population" IP
        where "Normalize Interval"(Obs.effective) overlaps IP.period
    )
    return {
      id: Obs.id,
      meta: Obs.meta,
      extension: Obs.extension,
      partOf: Obs.partOf,
      status: Obs.status,
      category: Obs.category,
      code: Obs.code,
      subject: Obs.subject,
      encounter: Obs.encounter,
      effective: Obs.effective,
      issued: Obs.issued,
      value: Obs.value,
      dataAbsentReason: Obs.dataAbsentReason,
      interpretation: Obs.interpretation,
      bodySite: Obs.bodySite,
      method: Obs.method,
      specimen: Obs.specimen,
      referenceRange: Obs.referenceRange,
      hasMember: Obs.hasMember,
      derivedFrom: Obs.derivedFrom,
      component: Obs.component
    }

// Minimal patient SDE


define "SDE Minimal Patient":
  [Patient] MinPt
    where exists ( "Initial Population" )
    return {
      id: MinPt.id,
      meta: MinPt.meta,
      extension: MinPt.extension,
      identifier: MinPt.identifier,
      active: MinPt.active,
      name: MinPt.name,
      telecom: MinPt.telecom,
      gender: MinPt.gender,
      birthDate: MinPt.birthDate,
      deceased: MinPt.deceased,
      address: MinPt.address,
      maritalStatus: MinPt.maritalStatus,
      multipleBirth: MinPt.multipleBirth,
      photo: MinPt.photo,
      contact: MinPt.contact,
      communication: MinPt.communication,
      generalPractitioner: MinPt.generalPractitioner,
      managingOrganization: MinPt.managingOrganization,
      link: MinPt.link
    }

define "SDE Medication":
  ( [MedicationRequest]
    union [MedicationAdministration] ) MedReqOrAdmin
    let medication: GetMedication(MedReqOrAdmin.medication as Reference)
    where medication is not null
      and exists ( "Initial Population" IP
          where Coalesce("Normalize Interval"(MedReqOrAdmin.effective), MedReqOrAdmin.authoredOn.toInterval()) overlaps IP.period
      )
    return {
      id: medication.id,
      meta: medication.meta,
      code: medication.code,
      status: medication.status,
      manufacturer: medication.manufacturer,
      form: medication.form,
      amount: medication.amount,
      ingredient: medication.ingredient,
      batch: medication.batch
    }

// SDE Medication Request - regular requests (doNotPerform is false or absent)


define "SDE Medication Request Base":
  [MedicationRequest] MedRequests
    where exists ( "Initial Population" IP
        where MedRequests.authoredOn during IP.period
    )
    return {
      id: MedRequests.id,
      meta: MedRequests.meta,
      status: MedRequests.status,
      statusReason: MedRequests.statusReason,
      intent: MedRequests.intent,
      category: MedRequests.category,
      priority: MedRequests.priority,
      //doNotPerform: MedRequests.doNotPerform,
      
      reported: MedRequests.reported,
      medication: MedRequests.medication,
      subject: MedRequests.subject,
      encounter: MedRequests.encounter,
      authoredOn: MedRequests.authoredOn,
      requester: MedRequests.requester,
      recorder: MedRequests.recorder,
      reasonCode: MedRequests.reasonCode,
      reasonReference: MedRequests.reasonReference,
      instantiatesCanonical: MedRequests.instantiatesCanonical,
      instantiatesUri: MedRequests.instantiatesUri,
      courseOfTherapyType: MedRequests.courseOfTherapyType,
      dosageInstruction: MedRequests.dosageInstruction
    }

// Combined SDE for all Medication Requests (both regular and negation)


define "SDE Medication Request":
  "SDE Medication Request Base"
    union "SDE Medication Not Requested"

define "SDE IP Encounters":
  "Initial Population" IP
    return {
      id: IP.id,
      meta: IP.meta,
      identifier: IP.identifier,
      status: IP.status,
      statusHistory: IP.statusHistory,
      class: IP.class,
      classHistory: IP.classHistory,
      type: IP.type,
      serviceType: IP.serviceType,
      priority: IP.priority,
      subject: IP.subject,
      period: IP.period,
      length: IP.length,
      reasonCode: IP.reasonCode,
      reasonReference: IP.reasonReference,
      diagnosis: IP.diagnosis,
      account: IP.account,
      hospitalization: IP.hospitalization,
      location: IP.location,
      partOf: IP.partOf
    }

define "SDE Observation Simple":
  [SimpleObservation] Obs
    where ( exists ( Obs.category Category
          where Category ~ "social-history"
      )
        or exists ( Obs.category Category
            where Category ~ "imaging"
        )
        or exists ( Obs.category Category
            where Category ~ "procedure"
        )
    )
      and exists ( "Initial Population" IP
          where "Normalize Interval"(Obs.effective) overlaps IP.period
      )
    return {
      id: Obs.id,
      meta: Obs.meta,
      extension: Obs.extension,
      partOf: Obs.partOf,
      status: Obs.status,
      category: Obs.category,
      code: Obs.code,
      subject: Obs.subject,
      encounter: Obs.encounter,
      effective: Obs.effective,
      issued: Obs.issued,
      value: Obs.value,
      dataAbsentReason: Obs.dataAbsentReason,
      interpretation: Obs.interpretation,
      bodySite: Obs.bodySite,
      method: Obs.method,
      specimen: Obs.specimen,
      referenceRange: Obs.referenceRange,
      hasMember: Obs.hasMember,
      derivedFrom: Obs.derivedFrom,
      component: Obs.component
    }

// Observation SDEs


define "SDE Observation Lab Category":
  [LaboratoryResultObservation] Obs
    where exists ( "Initial Population" IP
        where "Normalize Interval"(Obs.effective) overlaps IP.period
    )
    return {
      id: Obs.id,
      meta: Obs.meta,
      extension: Obs.extension,
      partOf: Obs.partOf,
      status: Obs.status,
      category: Obs.category,
      code: Obs.code,
      subject: Obs.subject,
      encounter: Obs.encounter,
      effective: Obs.effective,
      issued: Obs.issued,
      value: Obs.value,
      dataAbsentReason: Obs.dataAbsentReason,
      interpretation: Obs.interpretation,
      bodySite: Obs.bodySite,
      method: Obs.method,
      specimen: Obs.specimen,
      referenceRange: Obs.referenceRange,
      hasMember: Obs.hasMember,
      derivedFrom: Obs.derivedFrom,
      component: Obs.component
    }

define "SDE Medication Administration Base":
  [MedicationAdministration] MedAdministrations
    where exists ( "Initial Population" IP
        where "Normalize Interval"(MedAdministrations.effective) overlaps IP.period
    )
    return {
      id: MedAdministrations.id,
      meta: MedAdministrations.meta,
      instantiates: MedAdministrations.instantiates,
      partOf: MedAdministrations.partOf,
      status: MedAdministrations.status,
      statusReason: MedAdministrations.statusReason,
      category: MedAdministrations.category,
      medication: MedAdministrations.medication,
      subject: MedAdministrations.subject,
      context: MedAdministrations.context,
      supportingInformation: MedAdministrations.supportingInformation,
      effective: MedAdministrations.effective,
      performer: MedAdministrations.performer,
      reasonCode: MedAdministrations.reasonCode,
      reasonReference: MedAdministrations.reasonReference,
      request: MedAdministrations.request,
      device: MedAdministrations.device,
      note: MedAdministrations.note,
      dosage: MedAdministrations.dosage
    }

// Medication SDEs


define "SDE Medication Administration":
  "SDE Medication Administration Base"
    union "SDE Medication Administration Not Done"

// DiagnosticReport SDEs


define "SDE DiagnosticReport Lab":
  [DiagnosticReportLab] dr
    where exists ( "Initial Population" IP
        where "Normalize Interval"(dr.effective) overlaps IP.period
    )

// ----------------------------------------------------------------------
// Core retrieves
// ----------------------------------------------------------------------

// Locations from IP encounters





define "Get Locations from IP Encounters in Measurement Period":
  flatten ( "Initial Population" IP
      let locationElements: IP.location
      return locationElements LE
        let locationReference: LE.location
        return locationReference.getLocation ( )
  )

// Location SDE


define "SDE Location":
  "Get Locations from IP Encounters in Measurement Period" Locations
    where exists ( "Initial Population" )
      and Locations is not null
    return {
      id: Locations.id,
      meta: Locations.meta,
      extension: Locations.extension,
      status: Locations.status,
      operationalStatus: Locations.operationalStatus,
      name: Locations.name,
      alias: Locations.alias,
      description: Locations.description,
      mode: Locations.mode,
      type: Locations.type,
      telecom: Locations.telecom,
      address: Locations.address,
      physicalType: Locations.physicalType,
      position: Locations.position,
      managingOrganization: Locations.managingOrganization,
      partOf: Locations.partOf,
      hoursOfOperation: Locations.hoursOfOperation,
      availabilityExceptions: Locations.availabilityExceptions,
      endpoint: Locations.endpoint
    }

define "SDE DiagnosticReport Note":
  [DiagnosticReportNote] dr
    where ( exists ( dr.category Category
          where Category ~ "Radiology"
      )
        or exists ( dr.category Category
            where Category ~ "Pathology"
        )
        or exists ( dr.category Category
            where Category ~ "Cardiology"
        )
    )
      and exists ( "Initial Population" IP
          where "Normalize Interval"(dr.effective) overlaps IP.period
      )
    return {
      id: dr.id,
      meta: dr.meta,
      extension: dr.extension,
      basedOn: dr.basedOn,
      status: dr.status,
      category: dr.category,
      code: dr.code,
      subject: dr.subject,
      encounter: dr.encounter,
      effective: dr.effective,
      issued: dr.issued,
      specimen: dr.specimen,
      result: dr.result,
      conclusion: dr.conclusion,
      conclusionCode: dr.conclusionCode
    }

// ----------------------------------------------------------------------
// SDEs
// ----------------------------------------------------------------------




define "SDE Condition Problems HealthConcerns":
  [ConditionProblemsHealthConcerns] Diagnosis
    where exists ( "Initial Population" IP
        where Diagnosis.prevalenceInterval ( ) overlaps day of IP.period
    )
    return {
      id: Diagnosis.id,
      meta: Diagnosis.meta,
      status: Diagnosis.clinicalStatus,
      verificationStatus: Diagnosis.verificationStatus,
      category: Diagnosis.category,
      severity: Diagnosis.severity,
      code: Diagnosis.code,
      bodySite: Diagnosis.bodySite,
      subject: Diagnosis.subject,
      encounterReferenceId: Diagnosis.encounter.reference.getId ( ),
      onset: Diagnosis.onset,
      stage: Diagnosis.stage,
      evidence: Diagnosis.evidence,
      note: Diagnosis.note
    }

define "SDE Condition Diagnosis":
  [ConditionEncounterDiagnosis] Diagnosis
    where exists ( "Initial Population" IP
        where Diagnosis.prevalenceInterval ( ) overlaps day of IP.period
    )
    return {
      id: Diagnosis.id,
      meta: Diagnosis.meta,
      status: Diagnosis.clinicalStatus,
      verificationStatus: Diagnosis.verificationStatus,
      category: Diagnosis.category,
      severity: Diagnosis.severity,
      code: Diagnosis.code,
      bodySite: Diagnosis.bodySite,
      subject: Diagnosis.subject,
      encounterReferenceId: Diagnosis.encounter.reference.getId ( ),
      onset: Diagnosis.onset,
      stage: Diagnosis.stage,
      evidence: Diagnosis.evidence,
      note: Diagnosis.note
    }

// ----------------------------------------------------------------------
// Helper functions
// ----------------------------------------------------------------------




define function "CheckIP"(encounter Encounter):
  exists ( "Initial Population" IP
      where encounter.id = IP.id
  )

// Former NHSNHelpers functions, adapted for QI Core


define function "Normalize Interval"(choice Choice<DateTime, Interval<DateTime>>):
  case
    when choice is DateTime then Interval[choice as DateTime, choice as DateTime]
    when choice is Interval<DateTime>then choice as Interval<DateTime>
    else null as Interval<DateTime>end

define function "GetMedication"(reference Reference):
  singleton from ( [Medication] Medication
      where reference.references ( Medication )
  )

/*
@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

/*
@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 string): 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
        }

define function ToDateTime(value dateTime): value.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

/*
@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: 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 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 id of the given uri (i.e. everything after the last slash)
*/
define fluent function getId(uri String):
  Last(Split(uri, '/'))