define "Initial Population":
  AgeInYearsAt(start of("Index Depression Assessment".effective.toInterval())) >= 12

define "Denominator":
  "Initial Population"

define "Denominator Exclusions":
  "Has Hospice Services prior to or during the Measure Assessment Period"
    or "Has Palliative Care prior to or during the Measure Assessment Period"
    or "Patient Expired"
    or "Has Mental Health Disorder Diagnoses"

define "Numerator":
  Last([ObservationScreeningAssessment: "PHQ 9 and PHQ 9M Tools"] DepressionAssessment
      where start of DepressionAssessment.effective.toInterval() during day of "Measure Assessment Period"
        and DepressionAssessment.status in { 'final', 'amended', 'corrected' }
      sort by start of effective.toInterval()
  ).value < 5

define "Stratification 1":
  "Index Depression Assessment" IndexAssessment
    return AgeInYearsAt(date from start of IndexAssessment.effective.toInterval()) in Interval[12, 17]

define "Stratification 2":
  "Index Depression Assessment" IndexAssessment
    return AgeInYearsAt(date from start of IndexAssessment.effective.toInterval()) >= 18

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

define "SDE Payer":
  [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 "Depression Assessments Greater Than 9":
  [ObservationScreeningAssessment: "PHQ 9 and PHQ 9M Tools"] DepressionAssessment
    where DepressionAssessment.value > 9
      and DepressionAssessment.status in { 'final', 'amended', 'corrected' }

define "Depression Diagnoses":
  ( [ConditionProblemsHealthConcerns: "Major Depression Including Remission"]
    union [ConditionEncounterDiagnosis: "Major Depression Including Remission"]
    union [ConditionProblemsHealthConcerns: "Dysthymia"]
    union [ConditionEncounterDiagnosis: "Dysthymia"] ) Depression
    where Depression.isVerified ( )

define "Denominator Identification Period":
  Interval[start of "Measurement Period" - 14 months, start of "Measurement Period" - 2 months )

define "Depression Encounter":
  [Encounter: "Contact or Office Visit"] ValidEncounter
    with "Depression Diagnoses" Depression
      such that ValidEncounter.period overlaps Depression.prevalenceInterval ( )
        and ValidEncounter.period ends during day of "Denominator Identification Period"
        and ValidEncounter.status = 'finished'

define "Index Depression Assessment":
  First("Depression Assessments Greater Than 9" DepressionAssessment
      with "Depression Encounter" DepressionEncounter
        such that DepressionAssessment.effective.toInterval() during day of Interval[start of DepressionEncounter.period - 7 days, 
        end of DepressionEncounter.period]
      sort by start of effective.toInterval()
  )

define "Measure Assessment Period":
  "Index Depression Assessment" FirstIndexAssessment
    let YearAfterIndexAssessment: date from start of FirstIndexAssessment.effective.toInterval ( ) + 12 months
    return Interval[YearAfterIndexAssessment - 60 days, YearAfterIndexAssessment + 60 days]

define "Numerator":
  Last([ObservationScreeningAssessment: "PHQ 9 and PHQ 9M Tools"] DepressionAssessment
      where start of DepressionAssessment.effective.toInterval() during day of "Measure Assessment Period"
        and DepressionAssessment.status in { 'final', 'amended', 'corrected' }
      sort by start of effective.toInterval()
  ).value < 5

define "Stratification 2":
  "Index Depression Assessment" IndexAssessment
    return AgeInYearsAt(date from start of IndexAssessment.effective.toInterval()) >= 18

define "Stratification 1":
  "Index Depression Assessment" IndexAssessment
    return AgeInYearsAt(date from start of IndexAssessment.effective.toInterval()) in Interval[12, 17]

define "Initial Population":
  AgeInYearsAt(start of("Index Depression Assessment".effective.toInterval())) >= 12

define "Denominator":
  "Initial Population"

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

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

define "Has Hospice Services prior to or during the Measure Assessment Period":
  exists ( [Encounter: "Encounter Inpatient"] 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 Interval[start of "Denominator Identification Period", end of "Measure Assessment Period"]
        and InpatientEncounter.status = 'finished'
  )
    or exists ( [Encounter: "Hospice Encounter"] HospiceEncounter
        where HospiceEncounter.period overlaps day of Interval[start of "Denominator Identification Period", end of "Measure Assessment Period"]
          and not ( HospiceEncounter.status in { 'cancelled', 'entered-in-error', 'unknown' } )
    )
    or exists ( [ObservationScreeningAssessment: "Hospice care [Minimum Data Set]"] HospiceAssessment
        where HospiceAssessment.value ~ "Yes (qualifier value)"
          and HospiceAssessment.effective.toInterval ( ) overlaps day of Interval[start of "Denominator Identification Period", end of "Measure Assessment Period"]
          and HospiceAssessment.status in { 'final', 'amended', 'corrected' }
    )
    or exists ( [ServiceRequest: "Hospice Care Ambulatory"] HospiceOrder
        where HospiceOrder.authoredOn during day of Interval[start of "Denominator Identification Period", end of "Measure Assessment Period"]
          and HospiceOrder.status in { 'active', 'completed' }
          and HospiceOrder.intent in { 'order', 'original-order', 'reflex-order', 'filler-order', 'instance-order' }
    )
    or exists ( [Procedure: "Hospice Care Ambulatory"] HospicePerformed
        where HospicePerformed.performed.toInterval ( ) overlaps day of Interval[start of "Denominator Identification Period", end of "Measure Assessment Period"]
          and not ( HospicePerformed.status in { 'not-done', 'entered-in-error', 'unknown' } )
    )
    or exists ( ( [ConditionProblemsHealthConcerns: "Hospice Diagnosis"]
        union [ConditionEncounterDiagnosis: "Hospice Diagnosis"] ) HospiceCareDiagnosis
        where HospiceCareDiagnosis.prevalenceInterval ( ) overlaps day of Interval[start of "Denominator Identification Period", end of "Measure Assessment Period"]
          and HospiceCareDiagnosis.isVerified ( )
    )

define "Has Palliative Care prior to or during the Measure Assessment Period":
  exists ( [ObservationScreeningAssessment: "Functional Assessment of Chronic Illness Therapy - Palliative Care Questionnaire (FACIT-Pal)"] PalliativeAssessment
      where PalliativeAssessment.effective.toInterval ( ) overlaps day of Interval[start of "Denominator Identification Period", end of "Measure Assessment Period"]
        and PalliativeAssessment.status in { 'final', 'amended', 'corrected' }
  )
    or exists ( ( [ConditionProblemsHealthConcerns: "Palliative Care Diagnosis"]
        union [ConditionEncounterDiagnosis: "Palliative Care Diagnosis"] ) PalliativeDiagnosis
        where PalliativeDiagnosis.prevalenceInterval ( ) overlaps day of Interval[start of "Denominator Identification Period", end of "Measure Assessment Period"]
          and PalliativeDiagnosis.isVerified ( )
    )
    or exists ( [Encounter: "Palliative Care Encounter"] PalliativeEncounter
        where PalliativeEncounter.period overlaps day of Interval[start of "Denominator Identification Period", end of "Measure Assessment Period"]
          and PalliativeEncounter.status = 'finished'
    )
    or exists ( [Procedure: "Palliative Care Intervention"] PalliativeIntervention
        where PalliativeIntervention.performed.toInterval ( ) overlaps day of Interval[start of "Denominator Identification Period", end of "Measure Assessment Period"]
          and not ( PalliativeIntervention.status in { 'not-done', 'entered-in-error', 'unknown' } )
    )

define "Patient Expired":
  Patient.deceased occurs on or before day of end of "Measure Assessment Period"

define "Has Mental Health Disorder Diagnoses":
  exists ( ( [ConditionProblemsHealthConcerns: "Bipolar Disorder"]
      union [ConditionEncounterDiagnosis: "Bipolar Disorder"]
      union [ConditionProblemsHealthConcerns: "Personality Disorder Emotionally Labile"]
      union [ConditionEncounterDiagnosis: "Personality Disorder Emotionally Labile"]
      union [ConditionProblemsHealthConcerns: "Schizophrenia or Psychotic Disorder"]
      union [ConditionEncounterDiagnosis: "Schizophrenia or Psychotic Disorder"]
      union [ConditionProblemsHealthConcerns: "Pervasive Developmental Disorder"]
      union [ConditionEncounterDiagnosis: "Pervasive Developmental Disorder"] ) MentalHealthDisorderDiagnoses
      where start of MentalHealthDisorderDiagnoses.prevalenceInterval ( ) on or before day of end of "Measure Assessment Period"
        and MentalHealthDisorderDiagnoses.isVerified ( )
  )

define "Denominator Exclusions":
  "Has Hospice Services prior to or during the Measure Assessment Period"
    or "Has Palliative Care prior to or during the Measure Assessment Period"
    or "Patient Expired"
    or "Has Mental Health Disorder Diagnoses"

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

define function ToString(value uri): 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]

/*
@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
        }

/*
@description: Normalizes a value that is a choice of timing-valued types to an equivalent interval
@comment: Normalizes a choice type of DateTime, Quanitty, Interval<DateTime>, or Interval<Quantity> 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 QICore, allowing this function to be used across any resource.
The input can be provided as a DateTime, Quantity, Interval<DateTime> or Interval<Quantity>.
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 Quantity, the quantity is expected to be a calendar-duration interpreted as an Age,
and the result is a DateTime Interval beginning on the Date the patient turned that age and ending immediately before one year later.
If the input is a DateTime Interval, the result is the input.
If the input is a Quantity Interval, the quantities are expected to be calendar-durations interpreted as an Age, and the result
is a DateTime Interval beginning on the date the patient turned the age given as the start of the quantity interval, and ending
immediately before one year later than the date the patient turned the age given as the end of the quantity interval.
If the input is a Timing, an error will be thrown indicating that Timing calculations are not implemented. Any other input will reslt in a null DateTime Interval
*/
define fluent function toInterval(choice Choice<DateTime, Quantity, Interval<DateTime>, Interval<Quantity>, Timing>):
  case
	  when choice is DateTime then
    	Interval[choice as DateTime, choice as DateTime]
		when choice is Interval<DateTime> then
  		choice as Interval<DateTime>
		when choice is Quantity then
		  Interval[Patient.birthDate + (choice as Quantity),
			  Patient.birthDate + (choice as Quantity) + 1 year)
		when choice is Interval<Quantity> then
		  Interval[Patient.birthDate + (choice.low as Quantity),
			  Patient.birthDate + (choice.high as Quantity) + 1 year)
		when choice is Timing then
      Message(null, true, 'NOT_IMPLEMENTED', 'Error', 'Calculation of an interval from a Timing value is not supported') as Interval<DateTime>
		else
			null as Interval<DateTime>
	end