/* End of Key population member B.DE49 */

/*
@dataElement: HIV.B.DE50 - Key population member type
@activity: HIV.B6 Capture or update client history
@description: The type of key population that the client is included in
*/
define "Key population member type Observation":
  [Observation: Concepts."Key population member - HIV.B.DE49"] O
    where O.status in { 'final', 'amended', 'corrected' }
    and exists(O.category OC where OC ~ ConceptsCustom."social-history")

define "Key population member type Observation":
  Elements."Key population member type Observation" O
    where O.effective.toInterval() before end of "Measurement Period"
    or O.issued before end of "Measurement Period"

/* End of Trans and gender-diverse people B.DE53 */

/*
@dataElement: HIV.B.DE54 - People who inject drugs
@activity: HIV.B6 Capture or update client history
@description: Client is a person who injects drugs
*/
define "People who inject drugs":
  exists("Key population member type Observation" O
    where O.value ~ Concepts."People who inject drugs - HIV.B.DE54"
    and O.effective.toInterval() during "Measurement Period")

define "OAMT status":
    [EpisodeOfCare] EOC
    where exists(EOC.type T where T ~ Concepts."OAMT")
    return EOC.period

// TODO: doesn't compile DeviceUseStatement causes translation error
  // exists(Elements."Date injecting equipment provided" DUS
  // where DUS.timing.toInterval() during "Measurement Period")
/* End of Date injecting equipment provided */

/*
@dataElement: HIV.PRV.DE17 - Date OAMT initiated
@activity: HIV.B21 Offer prevention options
@description: Date client initiated opioid agonist maintenance treatment (OAMT)
*/
// TODO: Replace placeholder with relevant CQL logic

/* End of Date OAMT initiated */

/*
@dataElement: HIV.PRV.DE20 - Currently on OAMT
@activity: HIV.B6 Capture or update client history
@description: Client is currently on opioid agonist maintenance treatment (OAMT) at reporting date, defined according to country/program to account for medication dispensed and LTFU criterion
*/
define "Currently on OAMT":
  exists(Elements."OAMT status" p
    where p.toInterval() overlaps "Measurement Period")

/**
 * Numerator
 * 
 * Definition: Number of people on OAMT at specified census date
 * Calculation: Number of clients with "Key population member type"='People who inject drugs' AND "Currently on OAMT"=True for a specific "Reporting date"
 */

define "Numerator":
  HIE."People who inject drugs" and HIE."Currently on OAMT"

/* End of HIV prevention intervention */

/*
@dataElement: HIV.PRV.DE3 - PrEP service
@activity: HIV.B6 Capture or update client history
@description: Client accessed PrEP services
*/

define "PrEP service":
  [MedicationStatement] MS
    where exists(MS.reasonCode C where C ~ Concepts."PrEP for HIV prevention")
    sort by start of effective.toInterval()

define "OAMT statusHistory":
    [EpisodeOfCare] EOC
    where exists(EOC.type T where T ~ Concepts."OAMT") 
    and (exists (
      EOC.statusHistory H
      where H.period is not null))

/* End of PrEP service */

/*
@dataElement: HIV.PRV.DE4 - OAMT
@activity: HIV.B6 Capture or update client history
@description: Client accessed opioid agonist maintenance treatment (OAMT) services
*/

define "OAMT":
  flatten{"OAMT status","OAMT statusHistory".statusHistory.period}

//return start of "OAMT statusHistory".statusHistory.period
    //need to ask brynn

/* End of OAMT */

/*
@dataElement: HIV.PRV.DE5 - NSP
@activity: HIV.B6 Capture or update client history
@description: Client accessed needle-syringe programme (NSP) services
*/

define "NSP":
  false

// TODO: fix device use statement 
  // [DeviceUseStatement] DUS
  // with [Device: ConceptsCustom."needle-syringe"] D
  //     such that DUS.reasonReference.references(D) 
  //       and D.status in { 'active' }
  // where DUS.status = 'completed'

  // define "NSP date":
  // [DeviceUseStatement] DUS
  // with [Device: ConceptsCustom."needle-syringe"] D
  //     such that DUS.reasonReference.references(D) 
  //       and D.status in { 'active' }
  // where DUS.status = 'completed'
  // return start of DUS.timing.toInterval()
/* End of NSP */

/*
@dataElement: HIV.PRV.DE6 - STI services
@activity: HIV.B6 Capture or update client history
@description: Client accessed sexually transmitted infection (STI) services
*/

define "STI services":
  [Procedure] P
  where P.status = 'completed'
  and P.code ~ Concepts."STI testing and treatment services"

/* End of STI services */

/*
@dataElement: HIV.PRV.DE7 - VMMC
@activity: HIV.B6 Capture or update client history
@description: Client accessed voluntary medical male circumcision (VMMC) services
*/
// define "VMMC_done":
// [Procedure] P
//   where P.status = 'completed'
//   and P.code ~ Concepts."Voluntary medical male circumcision VMMC"


define "VMMC":
  [Procedure] P
  where P.status = 'completed'
  and P.code ~ Concepts."VMMC procedure"

/* End of VMMC */

/*
@dataElement: HIV.PRV.DE8 - Other
@activity: HIV.B6 Capture or update client history
@description: Client accessed other HIV prevention services
*/

define "Other PRV.DE8":
  [Observation] O
    where O.status in {'final', 'amended'}
    and O.code ~ Concepts."HIV prevention intervention"
    and O.value ~ Concepts."Other - HIV.PRV.DE8"
    sort by start of effective.toInterval()

/* End of At elevated risk for HIV acquisition PRV.DE1 */

/*
@dataElement: HIV.PRV.DE2 - HIV prevention intervention
@activity: HIV.B6 Capture or update client history
@description: HIV prevention intervention that client accessed
*/

define "HIV prevention intervention":
  exists ("PrEP service") or exists("OAMT") or "NSP" or exists("STI services") or exists("VMMC") or exists("Other PRV.DE8")

/**
 * Denominator
 *
 * Definition: a) Programme/service provider level: number of opioid dependent people accessing service | b) Population level: population size estimate of opioid dependent people in relevant geographic area
 * Calculation: Programme/service provider level: | COUNT of opioid dependent people accessing service |  | Population level:  | *Estimated population size of opioid dependent people in relevant geographic area
 */

define "Denominator":
  HE."HIV prevention intervention" and HIE."People who inject drugs"

/* Populations */

/*
 *Initial Population
 */

define "Initial Population":
  true

define function ToString(value ObservationStatus): value.value

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 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 ToDateTime(value instant): value.value

/*
From FHIRCommon 4.1.0:
*/

/*
@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

define function ToDateTime(value dateTime): value.value

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 ToDate(value date): value.value

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

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 ProcedureStatus): value.value