define "Initial Population":
  "Encounter With Hypoglycemic Medication Administration"

define "Denominator":
  "Initial Population"

define "Numerator":
  "Encounter With Severe Hypoglycemic Harm Event"

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 "Qualifying Encounter":
  ["Encounter": "Encounter Inpatient"] InpatientEncounter
    where AgeInYearsAt(date from start of InpatientEncounter.period) >= 18
      and InpatientEncounter.period ends during day of "Measurement Period"
      and InpatientEncounter.status = 'finished'

define "Hypoglycemic Medication Administration":
  ["MedicationAdministration": "Hypoglycemics Severe Hypoglycemia"] HypoMedication
    where HypoMedication.status = 'completed'

define "Encounter With Hypoglycemic Medication Administration":
  "Qualifying Encounter" InpatientHospitalization
    with "Hypoglycemic Medication Administration" HypoglycemicMedication
      such that HypoglycemicMedication.effective.toInterval ( ) starts during InpatientHospitalization.hospitalizationWithObservation ( )

define "Initial Population":
  "Encounter With Hypoglycemic Medication Administration"

define "Denominator":
  "Initial Population"

define "Glucose Test With Result Less Than 40":
  from
    "Denominator" InpatientHospitalization,
    "Hypoglycemic Medication Administration" HypoglycemicMedication,
    ["LaboratoryResultObservation": "Glucose Lab Test Mass Per Volume"] GlucoseTest
    let HospitalizationInterval: InpatientHospitalization.hospitalizationWithObservation ( ),
    HypoglycemicMedicationStart: HypoglycemicMedication.effective.toInterval ( ),
    GlucoseTestTime: GlucoseTest.effective.earliest ( )
    where GlucoseTestTime during HospitalizationInterval
      and GlucoseTest.status in { 'final', 'amended', 'corrected' }
      and GlucoseTest.value < 40 'mg/dL'
      and HypoglycemicMedicationStart starts 24 hours or less before or on GlucoseTestTime
    return GlucoseTest

define "Low Glucose Test Followed By Glucose Test Result Greater Than 80":
  from
    "Denominator" InpatientHospitalization,
    "Glucose Test With Result Less Than 40" LowGlucoseTest,
    ["LaboratoryResultObservation": "Glucose Lab Test Mass Per Volume"] FollowupGlucoseTest
    let GlucoseTestTime: LowGlucoseTest.effective.earliest ( ),
    FollowupGlucoseTestTime: FollowupGlucoseTest.effective.earliest ( )
    where FollowupGlucoseTestTime 5 minutes or less after GlucoseTestTime
      and GlucoseTestTime during InpatientHospitalization.hospitalizationWithObservation ( )
      and FollowupGlucoseTestTime during InpatientHospitalization.hospitalizationWithObservation ( )
      and FollowupGlucoseTest.id !~ LowGlucoseTest.id
      and FollowupGlucoseTest.status in { 'final', 'amended', 'corrected' }
      and FollowupGlucoseTest.value > 80 'mg/dL'
    return LowGlucoseTest

define "Severe Hypoglycemic Harm Event":
  "Glucose Test With Result Less Than 40" LowGlucoseTest
    where not ( LowGlucoseTest.id in "Low Glucose Test Followed By Glucose Test Result Greater Than 80".id )

define "Encounter With Severe Hypoglycemic Harm Event":
  from
    "Denominator" InpatientHospitalization,
    "Severe Hypoglycemic Harm Event" HypoglycemicEvent
    let GlucoseTestTime: HypoglycemicEvent.effective.earliest ( ),
    HospitalizationInterval: InpatientHospitalization.hospitalizationWithObservation ( )
    where GlucoseTestTime during HospitalizationInterval
    return InpatientHospitalization

define "Numerator":
  "Encounter With Severe Hypoglycemic Harm Event"

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

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

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

/*
@description: Hospitalization with Observation returns the total interval from the start of any immediately prior emergency department visit through the observation visit to the discharge of the given encounter
*/
define fluent function hospitalizationWithObservation(TheEncounter Encounter ):
  TheEncounter Visit
  		let ObsVisit: Last([Encounter: "Observation Services"] LastObs
  				where LastObs.status = 'finished'
            and LastObs.period ends 1 hour or less on or before start of Visit.period
  				sort by end of period
  			),
  			VisitStart: Coalesce(start of ObsVisit.period, start of Visit.period),
  			EDVisit: Last([Encounter: "Emergency Department Visit"] LastED
  				where LastED.status = 'finished'
            and LastED.period ends 1 hour or less on or before VisitStart
  				sort by end of period
  			)
  		return Interval[Coalesce(start of EDVisit.period, VisitStart), end of Visit.period]

define function ToString(value string): value.value

define function ToString(value uri): value.value

define function ToDate(value date): 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 EncounterStatus): 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 MedicationAdministrationStatus): value.value

define function ToDateTime(value dateTime): value.value

define function ToDateTime(value instant): 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: 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: Given an interval, return the starting point if the interval has a starting boundary specified,
otherwise, return the ending point
*/
define fluent function earliest(choice Choice<FHIR.dateTime, FHIR.Period, FHIR.Age, FHIR.Range>):
  (choice.toInterval()) period
    return
      if (period.hasStart()) then start of period
      else end of period

/*
@description: Given an interval, return true if the interval has a starting boundary specified
(i.e. the start of the interval is not null and not the minimum DateTime value)
*/
define fluent function hasStart(period Interval<DateTime>):
  not ( start of period is null
      or start of period = minimum DateTime
  )

/*
@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 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
    }