define "SDE Sex":
  case
    when Patient.gender = 'male' then Code { code: 'M', system: 'http://hl7.org/fhir/v3/AdministrativeGender', display: 'Male' }
    when Patient.gender = 'female' then Code { code: 'F', system: 'http://hl7.org/fhir/v3/AdministrativeGender', display: 'Female' }
    else null
  end

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

define "Inpatient Encounter" :
  ["Encounter"] Encounter
    where LengthInDays(Encounter.period) <= 120
      and Encounter.period ends during "Measurement Period"

define "Initial Population" :
  "Inpatient Encounter" Encounter

define "SDE Ethnicity":
  (flatten (
    Patient.extension Extension
      where Extension.url = 'http://hl7.org/fhir/us/core/StructureDefinition/us-core-ethnicity'
        return Extension.extension
  )) E
    where E.url = 'ombCategory'
      or E.url = 'detailed'
    return E.value as Coding

define "SDE Race":
  (flatten (
    Patient.extension Extension
      where Extension.url = 'http://hl7.org/fhir/us/core/StructureDefinition/us-core-race'
        return Extension.extension
  )) E
    where E.url = 'ombCategory'
      or E.url = 'detailed'
    return E.value as Coding

define "Measure Population" :
  "Initial Population"

define function "LengthInDays"(Value Interval<DateTime>):
	difference in days between start of Value and end of Value

define function "Measure Observation" (Encounter "Encounter" ) :
  duration in minutes of "Related ED Visit"(Encounter).period

//Measure Observation
define function "Related ED Visit" (Encounter "Encounter" ) :
  Last(["Encounter" : "Emergency Department Visit"] ED
    where ED.status = 'finished'
      and ED.period ends 1 hour or less before start of Encounter.period
    sort by start of period )

define function ToString(value AdministrativeGender): 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 uri): value.value

define function ToString(value EncounterStatus): value.value