library RecommendImmunization

using FHIR version '4.0.1'

include FHIRHelpers version '4.0.1'

codesystem "Activity Type": 'http://hl7.org/fhir/uv/cpg/CodeSystem/cpg-activity-type-cs'
codesystem "Task Codes": 'http://hl7.org/fhir/CodeSystem/task-code'

code "Recommend Immunization": 'immunization-recommendation' from "Activity Type"
code "fulfill": 'fulfill' from "Task Codes" display 'Fulfill'

context Patient

/* Recommendation to immunize the patient */

/*
NOTE: This recommendation is dramatically simplified to illustrate the general
pattern for a positive recommendation, with the ability for users to reject
the recommendation, and flexibility in how the recommendation is achieved.

Specifically:
* There is no terminology, any immunization request/event on any topic will do
* There is no timing, any immunization request/event will do at any time
* There is no reference to participants other than the patient
* There is no relationship to a setting
* There is no relationship to an encounter or episode
* There is no relationship to a care plan

These simplifications allow the example to focus exclusively on the pattern for
recommending and for accepting/rejecting the proposal, as well as documenting
the completion, or explicit non-performance of the communication.
*/

/*
Positive recommendation:

If the activity has not been performed
  If the activity has not been planned or proposed
    Propose the activity

Given a proposal, the user can:
  Accept the proposal
  Ignore the proposal
  Reject the proposal without reason
  Reject the proposal with reason

Scenario 1: No event, no plan or proposal, decision support should propose
Scenario 2: No event, incomplete proposal, decision support should not propose
Scenario 3: No event, rejected proposal, decision support should not propose
Scenario 4: Event, no proposal, decision support should not propose
Scenario 5: Event, completed proposal, decision support should not propose
Scenario 6: Event not done, no proposal, decision support should not propose
Scenario 7: Event not done, proposal, decision support should not propose

*/

define "Inclusion Criteria":
  Patient.active

define "Active or Completed Immunization":
  [Immunization] C
    where C.status in { 'completed' }

define "Immunization Not Done":
  [Immunization] C
    where C.status in { 'not-done' }

define "Rejected Task":
  [Task] T
    where T.code ~ "fulfill"
      and T.status = 'rejected'

define "Immunization Proposal":
  [MedicationRequest] MR
    without "Rejected Task" T
      such that MR.id = Last(Split(T.focus.reference, '/'))
    where exists ( (MR.category) C where C ~ "Recommend Immunization" )
      and MR.status in { 'draft', 'active' }
      and MR.doNotPerform is not true

define "Immunization Prohibited":
  [MedicationRequest] MR
    where exists ( (MR.category) C where C ~ "Recommend Immunization" )
      and MR.status in { 'draft', 'active' }
      and MR.doNotPerform is true

define "Immunization Proposal Rejected":
  [MedicationRequest] MR
    with "Rejected Task" T
      such that MR.id = Last(Split(T.focus.reference, '/'))
    where exists ( (MR.category) C where C ~ "Recommend Immunization" )
      and MR.status = 'active'
      and MR.doNotPerform is not true

define "Is Recommendation Applicable":
  "Inclusion Criteria"
    and not exists (
      "Active or Completed Immunization"
        union "Immunization Not Done"
    )
    and not exists (
      "Immunization Proposal"
        union "Immunization Prohibited"
        union "Immunization Proposal Rejected"
    )

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