define "Topical Diclofenac Prescription":
  ContextPrescriptions P
    where P.medication in "Topical Diclofenac"
    return P.medication as CodeableConcept

define "Is context medication topical diclofenac":
  exists ("Topical Diclofenac Prescription")

define "Get Base Indicator":
  if "Is context medication topical diclofenac"
    then 'info'
  else 'warning'

define "PPIs and Misoprostols Rx":
    (
      [MedicationRequest: "PPIs and Misoprostols"] MR
        where MR.authoredOn.toInterval() during Interval[Today() - 100 days, null]
        return MR.medication as CodeableConcept
    )
    union (
      [MedicationAdministration: "PPIs and Misoprostols"] MA
        where MA.effective.toInterval() overlaps Interval[Today() - 100 days, null]
        return MA.medication as CodeableConcept
    )
    union (
      [MedicationDispense: "PPIs and Misoprostols"] MD
        where MD.whenHandedOver.toInterval() during Interval[Today() - 100 days, null]
        return MD.medication as CodeableConcept
    )
    union (
      [MedicationStatement: "PPIs and Misoprostols"] MS
        where MS.effective.toInterval() overlaps Interval[Today() - 100 days, null]
        return MS.medication as CodeableConcept
    )

define "Taking PPI or misoprostol":
  exists ("PPIs and Misoprostols Rx")

define "Get Card 2 Summary":
  if "Taking PPI or misoprostol"
    then 'Patient is taking a proton pump inhibitor ('
      + Common.GetDrugNames("PPIs and Misoprostols Rx")
      + ').'
  else 'Patient is not taking a proton pump inhibitor or misoprostol.'

define "Warfarin Rx":
    (
      [MedicationRequest: "Warfarins"] MR
        where MR.authoredOn.toInterval() during Interval[Today() - 100 days, null]
        return MR.medication as CodeableConcept
    )
    union (
      [MedicationAdministration: "Warfarins"] MA
        where MA.effective.toInterval() overlaps Interval[Today() - 100 days, null]
        return MA.medication as CodeableConcept
    )
    union (
      [MedicationDispense: "Warfarins"] MD
        where MD.whenHandedOver.toInterval() during Interval[Today() - 100 days, null]
        return MD.medication as CodeableConcept
    )
    union (
      [MedicationStatement: "Warfarins"] MS
        where MS.effective.toInterval() overlaps Interval[Today() - 100 days, null]
        return MS.medication as CodeableConcept
    )

define "Is warfarin in prefetch":
  exists ("Warfarin Rx")

define "NSAID Prescription":
  ContextPrescriptions P
    where P.medication in "NSAIDs"
    return P.medication as CodeableConcept

define "Is context medication systemic NSAID":
  exists ("NSAID Prescription")

/*
**
** Warfarin NSAID CDS Recommendation
**
*/

define "Inclusion Criteria":
  if "Is context medication topical diclofenac"
    then "Is warfarin in prefetch"
  else (
    "Is context medication systemic NSAID"
      and "Is warfarin in prefetch"
  )

define "GI Bleeds Condition":
  Last(
    [Condition: "History of GI Bleeds"] C
      sort by assertedDate().value
  )

define "Age > 65 years or Hx UGIB":
  "GI Bleeds Condition" is not null
    or AgeInYears() > 65

define "Get Card 3 Summary":
  if "Age > 65 years or Hx UGIB"
    then 'Patient is 65 y/o or does have a history of upper gastrointestinal bleed ("'
      + Common.GetConditionName("GI Bleeds Condition")
      + '" and '
      + Common.GetAssertedDate("GI Bleeds Condition")
      + ').'
  else 'Patient is not 65 y/o and does not have a history of upper gastrointestinal bleed.'

define "Systemic Corticosteroids Rx":
    (
      [MedicationRequest: "Systemic Corticosteroids"] MR
        where MR.authoredOn.toInterval() during Interval[Today() - 100 days, null]
        return MR.medication as CodeableConcept
    )
    union (
      [MedicationAdministration: "Systemic Corticosteroids"] MA
        where MA.effective.toInterval() overlaps Interval[Today() - 100 days, null]
        return MA.medication as CodeableConcept
    )
    union (
      [MedicationDispense: "Systemic Corticosteroids"] MD
        where MD.whenHandedOver.toInterval() during Interval[Today() - 100 days, null]
        return MD.medication as CodeableConcept
    )
    union (
      [MedicationStatement: "Systemic Corticosteroids"] MS
        where MS.effective.toInterval() overlaps Interval[Today() - 100 days, null]
        return MS.medication as CodeableConcept
    )

define "Has Systemic Corticosteroids":
  exists ("Systemic Corticosteroids Rx")

define "Aldosterone Antagonists Rx":
    (
      [MedicationRequest: "Aldosterone Antagonists"] MR
        where MR.authoredOn.toInterval() during Interval[Today() - 100 days, null]
        return MR.medication as CodeableConcept
    )
    union (
      [MedicationAdministration: "Aldosterone Antagonists"] MA
        where MA.effective.toInterval() overlaps Interval[Today() - 100 days, null]
        return MA.medication as CodeableConcept
    )
    union (
      [MedicationDispense: "Aldosterone Antagonists"] MD
        where MD.whenHandedOver.toInterval() during Interval[Today() - 100 days, null]
        return MD.medication as CodeableConcept
    )
    union (
      [MedicationStatement: "Aldosterone Antagonists"] MS
        where MS.effective.toInterval() overlaps Interval[Today() - 100 days, null]
        return MS.medication as CodeableConcept
    )

define "Has Aldosterone Antagonists":
  exists ("Aldosterone Antagonists Rx")

define "NSAID Rx":
    (
      [MedicationRequest: "NSAIDs"] MR
        where MR.authoredOn.toInterval() during Interval[Today() - 100 days, null]
        return MR.medication as CodeableConcept
    )
    union (
      [MedicationAdministration: "NSAIDs"] MA
        where MA.effective.toInterval() overlaps Interval[Today() - 100 days, null]
        return MA.medication as CodeableConcept
    )
    union (
      [MedicationDispense: "NSAIDs"] MD
        where MD.whenHandedOver.toInterval() during Interval[Today() - 100 days, null]
        return MD.medication as CodeableConcept
    )
    union (
      [MedicationStatement: "NSAIDs"] MS
        where MS.effective.toInterval() overlaps Interval[Today() - 100 days, null]
        return MS.medication as CodeableConcept
    )

define "Has NSAID":
  exists ("NSAID Rx")

define "Taking CS, MCRA, or NSAID":
  "Has Systemic Corticosteroids"
    or "Has Aldosterone Antagonists"
    or "Has NSAID"

define "Get Card 4 Summary":
  if "Taking CS, MCRA, or NSAID"
    then 'Patient is concomitantly taking systemic corticosteroids ('
      + Common.GetDrugNames("Systemic Corticosteroids Rx")
      + '), aldosterone antagonist ('
      + Common.GetDrugNames("Aldosterone Antagonists Rx")
      + '), or high dose or multiple NSAIDs ('
      + Common.GetDrugNames("NSAID Rx")
      + ').'
  else 'Patient is not concomitantly taking systemic corticosteroids, aldosterone antagonist, or high dose or multiple NSAIDs.'

define "Get Card 2 Detail":
  'Proton pump inhibitors and misoprostol may reduce the risk of UGIB in patients receiving NSAIDs and warfarin.'

define "Acetaminophen 500 MG": Code '198440' from "RXNORM" display 'Acetaminophen 500 MG Oral Tablet'

define "Get Base Label 2":
  'Substitute NSAID ('
  + Common.GetDrugNames("NSAID Prescription")
  + ') with APAP ('
  + Common.ToString("Acetaminophen 500 MG")
  + ').'

define "Get Card 2 Label":
  if "Taking PPI or misoprostol"
    then 'Assess risk and take action if necessary.'
  else 'Use only if benefit outweighs risk.'

define "Acetaminophen 325 MG": Code '313782' from "RXNORM" display 'Acetaminophen 325 MG Oral Tablet'

define "Get Base Label 1":
  'Substitute NSAID ('
  + Common.GetDrugNames("NSAID Prescription")
  + ') with APAP ('
  + Common.ToString("Acetaminophen 325 MG")
  + ').'

define "Get Card 4 Detail":
  'Both corticosteroids and aldosterone antagonists have been shown to subsetantially increase the risk of UGIB in patients on NSAIDs, with relative risks of 12.8 and 11 respectively compared to a risk of 4.3 with NSAIDs alone (Masclee et al. Gastroenterology 2014; 147:784-92.)'

// Card 4: Systemic Corticosteroids or Aldosterone Antagonist
define "Get Card 4 Indicator":
  if "Taking CS, MCRA, or NSAID"
    then 'warning'
  else 'info'

define "Get Card 3 Detail":
  'Patients with a history of UGIB or peptic ulcer may have an increased risk of UGIB from this interaction. The extent to which older age is an independent risk factor for UGIB due to these interactions is not firmly established, but UGIB in general is known to increase with age.'

// Card 3: History of UGIB/peptic ulcer or > 65 years old
define "Get Card 3 Indicator":
  if "Age > 65 years or Hx UGIB"
    then 'warning'
  else 'info'

define "Is not context medication topical diclofenac":
  not exists ("Topical Diclofenac Prescription")

define "Get Card 3 Label":
  if "Taking PPI or misoprostol"
    then 'Assess risk and take action if necessary.'
  else if "Age > 65 years or Hx UGIB"
    then 'Use only if benefit outweighs risk.'
  else 'Assess risk and take action if necessary.'

// Card 2: PPI or misoprostol
define "Get Card 2 Indicator":
  if "Taking PPI or misoprostol"
    then 'info'
  else 'critical'

// Card 1: Base
define "Get Base Summary":
  'Potential Drug-Drug Interaction between warfarin ('
    + Common.GetDrugNames("Warfarin Rx")
    + ') and NSAID ('
    + Common.GetDrugNames("NSAID Prescription")
    + ').'

define "Get Card 4 Label":
  if "Taking PPI or misoprostol"
    then 'Assess risk and take action if necessary.'
  else if "Taking CS, MCRA, or NSAID"
    then 'Use only if benefit outweighs risk.'
  else 'Assess risk and take action if necessary.'

/*
@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 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: 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 string): value.value

define function ToDateTime(value dateTime): 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 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

define function ToString(value uri): value.value

define function GetDrugNames(codes List<FHIR.CodeableConcept>):
  Combine(
    flatten(
      codes C
        return C.coding coding
          return ToCode(coding).display
    )
    ,', '
  )

define function ToCode(coding FHIR.Coding):
  System.Code {
    code: coding.code.value,
    system: coding.system.value,
    version: coding.version.value,
    display: coding.display.value
  }

define fluent function assertedDate(condition Condition):
  condition.ext('http://hl7.org/fhir/StructureDefinition/condition-assertedDate').value as dateTime

define function GetConditionName(condition Condition):
  if condition is not null
    then condition.code.coding[0].display.value
  else 'NA'

define function GetAssertedDate(condition Condition):
  if condition is not null
    then ToString(condition.assertedDate().value)
  else 'NA'

define function ToString(value Code): value.display