/// url = 'https://fhir.slade360.co.ke/fhir/StructureMap/ExtractPacuNursesNotes'
/// name = 'ExtractPacuNursesNotes'
/// title = 'PACU Nurses Notes Extraction'
/// status = 'active'
/// description = 'One Observation per note, under LOINC 34746-8, each carrying its own timestamp and the nurse who wrote it. Recovery is the window in which a patient deteriorates fastest, and a note that cannot say when it was written is not usable evidence of what was noticed.'

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

group ExtractPacuNursesNotes(source qr : QR, target bundle : Bundle) {
  qr -> bundle.type = 'transaction' "setBundleType";
  // One Observation per entry, each with its own time and its own author. A
  // ward or recovery note is evidence of when something was seen and by whom;
  // merging the sheet into one narrative destroys both.
  qr.item as row where ((linkId = 'entry') and item.where(linkId = 'entry/note').answer.value.exists()) ->  bundle.entry as entry,  entry.resource = create('Observation') as obs then {
    qr ->  obs,  entry then BuildObsBase(qr, obs, entry) "base";
    qr -> obs then SetSurveyCategory(qr, obs) "category";
    row -> obs.code as cc then {
      row -> cc.coding as cg then {
        row -> cg.system = 'http://loinc.org' "sys";
        row -> cg.code = '34746-8' "cd";
        row -> cg.display = 'Nurse Note' "dsp";
      } "coding";
      row -> cc.text = 'PACU nurses note' "codeText";
    } "code";
    row.item as it where (linkId = 'entry/note') then {
      it.answer first as a then {
        a.value as txt ->  obs.note as n,  n.text = txt "text";
      };
    } "textRule";
    row -> obs then SetPacuNursesRowTime(row, obs) "rowTime";
  } "entryRow";
  qr.item as g where (linkId = 'recovery') then {
    g.item as it where ((linkId = 'recovery/diagnosis') and answer.value.exists()) ->  bundle.entry as entry,  entry.resource = create('Observation') as obs then {
      qr ->  obs,  entry then BuildObsBase(qr, obs, entry) "base";
      qr -> obs then SetSurveyCategory(qr, obs) "category";
      it -> obs.code as cc then {
        it -> cc.coding as cg then {
          it -> cg.system = 'http://loinc.org' "sys";
          it -> cg.code = '11450-4' "cd";
          it -> cg.display = 'Problem list - Reported' "dsp";
        } "coding";
      } "code";
      it.answer first as a then {
        a.value as txt ->  obs.note as n,  n.text = txt "text";
      };
    } "narr_11450_4";
  } "headerGroup";
}

// The row's own timestamp on everything extracted from that row.
group SetPacuNursesRowTime(source row, target obs : Observation) {
  row.item as it where ((linkId = 'entry/at') and answer.value.exists()) then {
    it.answer first as a then {
      a.value as v -> obs.effective = v "effective";
    };
  } "rowTimeRule";
  row.item as it where ((linkId = 'entry/nurse') and answer.value.exists()) then {
    it.answer first as a then {
      a.value as ref -> obs.performer = ref "by";
    };
  } "rowByRule";
}

// ─────────────────────────────────────────────────────────────────────────────
// Shared scaffolding. Repeated in each map rather than imported: the transform
// engine resolves `imports` against whatever StructureMaps happen to be on the
// server, and a form that stops extracting because a shared map was not
// uploaded is a worse failure than a duplicated group.
// Two notes on what the publisher's StructureMap validator says about this file.
// Source parameters below are left untyped on purpose. Writing `: Element` makes
// the validator compare QuestionnaireResponse.item against the literal 'Element'
// and report them as incompatible with each other, which is noise, not a finding.
// `evaluate(context, expression)` is flagged as "takes 1 parameter but 2 were
// found". Leave it. The FML parser in the same jar refuses the one-argument form
// outright -- it wants a parameter, a comma, then the FHIRPath -- so the
// publisher is objecting to what its own compiler emits. Two arguments is the
// only form that compiles, and it is what the R5 transform engine executes.
// ─────────────────────────────────────────────────────────────────────────────
group BuildObsBase(source qr : QR, target obs : Observation, target entry) {
  qr -> obs then SetResponseProvenance(qr, obs) "responseProvenance";
  qr -> obs.id = uuid() then SetObservationFullUrl(obs, entry) "idAndFullUrl";
  qr -> entry.request as request then {
    qr -> request.method = 'POST' "requestMethod";
    qr -> request.url = 'Observation' "requestUrl";
  } "entryRequest";
  qr -> obs.status = 'final' "status";
  qr.subject as s -> obs.subject = s;
  qr.encounter as e -> obs.encounter = e;
  qr.authored as t -> obs.effective = t "effective";
  qr.source as src -> obs.performer = src "performerFromSource";
  qr where (source.exists().not()) then {
    qr.author as a -> obs.performer = a "performerFromAuthor";
  } "performerFallback";
  // A stored response's id already reads "QuestionnaireResponse/<id>", so it is
  // a relative reference as it stands. The hasValue() guard is what stops an
  // unsaved response -- one posted straight to $extract rather than saved first
  // -- from writing "QuestionnaireResponse/null" into the record.
  qr.id as qid where ($this.hasValue()) ->  obs.derivedFrom = create('Reference') as ref,  ref.reference = qid "linkQuestionnaireResponse";
}

group SetObservationFullUrl(source obs : Observation, target entry) {
  obs.id as id -> entry.fullUrl = append('https://fhir.slade360.co.ke/fhir/Observation/', id) "assignFullUrl";
}

// The two answer shapes a component can carry. Both read the answer through the
// untyped `.value` accessor: reading `valueCoding` or `valueQuantity` by its
// typed property name fails at transform time on HAPI R5 with "Attempt to read
// invalid property ... on QuestionnaireResponse.item.answer".
group SetComponentCodedValue(source it, target comp) {
  it.answer first as a then {
    a.value as cv -> comp.value = create('CodeableConcept') as cc then {
      cv -> cc.coding = cv "valueCoding";
      cv.display as d -> cc.text = d "valueText";
    } "codedValue";
  } "componentAnswer";
}

group SetComponentValue(source it, target comp) {
  it.answer first as a then {
    a.value as v -> comp.value = v "plainValue";
  } "componentAnswer";
}

group SetSurveyCategory(source qr : QR, target obs : Observation) {
  qr -> obs.category as cat then {
    qr -> cat.coding as coding then {
      qr -> coding.system = 'http://terminology.hl7.org/CodeSystem/observation-category' "categorySystem";
      qr -> coding.code = 'survey' "categoryCode";
      qr -> coding.display = 'Survey' "categoryDisplay";
    } "categoryCoding";
  } "category";
}

// ── Provenance and tenancy ───────────────────────────────────────────────────
// Two tags on everything this map creates. The first says which questionnaire
// produced it, so a form that reopens mid-admission recalls its own earlier
// entries and not another form's. The second copies the tenant tags off the
// response, because nothing else on the path puts them there.
// The code is the form's document type, not the questionnaire's id: every
// environment mints its own ids, and there is only one set of maps, so an id
// here would tie the tag to whichever environment stamped it.
// ── Provenance and tenancy ───────────────────────────────────────────────────
group SetResponseProvenance(source qr : QR, target r) {
  qr -> r.meta as m then {
    qr -> m.tag as t then {
      qr -> t.system = 'http://slade360edi.com/questionnaire-provenance' "provenanceSystem";
      qr -> t.code = 'pacu-nurses-notes' "provenanceCode";
      qr -> t.display = 'PACU nurses notes' "provenanceDisplay";
    } "provenanceTag";
  } "provenanceMeta";
  // Every tag the response carries, onto the resource. `meta` is 0..1, so this
  // lands on the same meta the rule above created rather than a second one.
  qr.meta as qm then {
    qm.tag as qt ->  r.meta as m,  m.tag = qt "copyTag";
  } "tenantTags";
}