map "https://fhir.hl7.at/prenudge/appdata/r4/StructureMap/Pss4QuestionnaireResponseToObservation" = "Pss4QuestionnaireResponseToObservation"

// PSS-4 Q score to O score

uses "http://hl7.org/fhir/StructureDefinition/QuestionnaireResponse" alias QR as source
uses "http://hl7.org/fhir/StructureDefinition/Observation" alias Obs as target

imports "http://hl7.org/fhir/StructureMap/*"
imports "https://fhir.hl7.at/prenudge/appdata/r4/StructureMap/QuestionnaireResponseToObservationBase"

group Pss4QuestionnaireResponseToObservation(source src : QR, target tgt : Obs) {
  src then SetObservationBase(src, tgt) "Base";
  src ->  tgt.meta as meta,  meta.profile = 'https://fhir.hl7.at/prenudge/appdata/r4/StructureDefinition/at-prenudge-pss4-score-observation' "SetProfile";
  src -> tgt.code = cc('https://fhir.hl7.at/prenudge/appdata/r4/CodeSystem/at-prenudge-pss-codes-codesystem', 'pss4', 'PSS-4 Perceived Stress Scale (4-item)') "SetCode";
  src.authored as authored ->  tgt.effectiveDateTime = create('dateTime') as dt,  dt.value = authored "SetEffective";
  src.item as pss4Group where linkId = 'pss4' then {
    // Map individual item codings → Observation components (raw categorical answers)
    pss4Group.item as q1 where linkId = 'pss4-q1' then MapPss4Q1(q1, tgt) "MapQ1";
    pss4Group.item as q2 where linkId = 'pss4-q2' then MapPss4Q2(q2, tgt) "MapQ2";
    pss4Group.item as q3 where linkId = 'pss4-q3' then MapPss4Q3(q3, tgt) "MapQ3";
    pss4Group.item as q4 where linkId = 'pss4-q4' then MapPss4Q4(q4, tgt) "MapQ4";
    // Map pre-computed total score → Observation.value
    pss4Group.item as totalItem where linkId = 'pss4-total-score' then MapPss4TotalScore(totalItem, tgt) "MapTotal";
  } "ProcessPss4";
}

group MapPss4Q1(source src : QR, target tgt : Obs) {
  src.answer as answer then {
    answer.valueCoding as vc ->  tgt.component as comp,  comp.code = cc('https://fhir.hl7.at/prenudge/appdata/r4/CodeSystem/at-prenudge-pss-codes-codesystem', 'pss4-q1', 'PSS-4 Item 1 (Kontrollverlust)'),  comp.value = create('CodeableConcept') as cc2,  cc2.coding = vc "SetComponent";
  } "ProcessAnswer";
}

group MapPss4Q2(source src : QR, target tgt : Obs) {
  src.answer as answer then {
    answer.valueCoding as vc ->  tgt.component as comp,  comp.code = cc('https://fhir.hl7.at/prenudge/appdata/r4/CodeSystem/at-prenudge-pss-codes-codesystem', 'pss4-q2', 'PSS-4 Item 2 (Selbstwirksamkeit — positiv)'),  comp.value = create('CodeableConcept') as cc2,  cc2.coding = vc "SetComponent";
  } "ProcessAnswer";
}

group MapPss4Q3(source src : QR, target tgt : Obs) {
  src.answer as answer then {
    answer.valueCoding as vc ->  tgt.component as comp,  comp.code = cc('https://fhir.hl7.at/prenudge/appdata/r4/CodeSystem/at-prenudge-pss-codes-codesystem', 'pss4-q3', 'PSS-4 Item 3 (Kontrolle — positiv)'),  comp.value = create('CodeableConcept') as cc2,  cc2.coding = vc "SetComponent";
  } "ProcessAnswer";
}

group MapPss4Q4(source src : QR, target tgt : Obs) {
  src.answer as answer then {
    answer.valueCoding as vc ->  tgt.component as comp,  comp.code = cc('https://fhir.hl7.at/prenudge/appdata/r4/CodeSystem/at-prenudge-pss-codes-codesystem', 'pss4-q4', 'PSS-4 Item 4 (Überforderung)'),  comp.value = create('CodeableConcept') as cc2,  cc2.coding = vc "SetComponent";
  } "ProcessAnswer";
}

// Pre-computed integer total score from the hidden pss4-total-score QR item.
// Two-level .value unwrap (integer) — MaLaC-HD safe pattern (no evaluate()).
group MapPss4TotalScore(source src : QR, target tgt : Obs) {
  src.answer as answer then {
    answer.valueInteger as val then {
      val.value as numVal ->  tgt.value = create('Quantity') as qty,  qty.value = numVal,  qty.unit = 'score',  qty.system = 'http://unitsofmeasure.org',  qty.code = '{score}' "SetQuantity";
    } "ExtractValue";
  } "ProcessAnswer";
}