/// url = 'https://fhir.slade360.co.ke/fhir/StructureMap/ExtractCpapMonitoringChart'
/// name = 'ExtractCpapMonitoringChart'
/// title = 'CPAP Monitoring Chart Extraction'
/// status = 'active'
/// description = 'One settings panel per reading rather than three loose Observations, for the same reason as the ventilator chart: a flow of 8 L/min means one thing at a distending pressure of 5 cmH2O and another at 8, and nobody joins three separate Observations by timestamp to see it. The panel is coded to LOINC 35410-0, continuous positive airway pressure, and the three columns ride as components under the codes the paper actually labels them with.'

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 ExtractCpapMonitoringChart(source qr : QR, target bundle : Bundle) {
  qr -> bundle.type = 'transaction' "setBundleType";
  qr.item as row where ((linkId = 'reading') and item.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 SetExamCategory(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 = '35410-0' "cd";
        row -> cg.display = 'Continuous positive airway pressure Respiratory system' "dsp";
      } "coding";
      row -> cc.text = 'CPAP settings on the monitoring chart' "codeText";
    } "code";
    // The paper labels this column PEEP, and on a CPAP circuit the distending
    // pressure and the end-expiratory pressure are the same number. Coded to
    // 20075-8 rather than repeating the panel code, so a query for PEEP across
    // the ventilator chart and this one finds both.
    row.item as it where ((linkId = 'reading/peep') and answer.value.exists()) -> obs.component as comp then {
      it -> comp.code as cc then {
        it -> cc.coding as cg then {
          it -> cg.system = 'http://loinc.org' "sys";
          it -> cg.code = '20075-8' "cd";
          it -> cg.display = 'PEEP Respiratory system' "dsp";
        } "coding";
      } "code";
      it -> comp then SetComponentValue(it, comp) "value";
    } "comp_20075_8";
    row.item as it where ((linkId = 'reading/flow') and answer.value.exists()) -> obs.component as comp then {
      it -> comp.code as cc then {
        it -> cc.coding as cg then {
          it -> cg.system = 'http://loinc.org' "sys";
          it -> cg.code = '3151-8' "cd";
          it -> cg.display = 'Inhaled oxygen flow rate' "dsp";
        } "coding";
      } "code";
      it -> comp then SetComponentValue(it, comp) "value";
    } "comp_3151_8";
    row.item as it where ((linkId = 'reading/fio2') and answer.value.exists()) -> obs.component as comp then {
      it -> comp.code as cc then {
        it -> cc.coding as cg then {
          it -> cg.system = 'http://loinc.org' "sys";
          it -> cg.code = '3150-0' "cd";
          it -> cg.display = 'Inhaled oxygen concentration' "dsp";
        } "coding";
      } "code";
      it -> comp then SetComponentValue(it, comp) "value";
    } "comp_3150_0";
    // Changes and remarks go to note, not to a component. A component needs a
    // code saying what its value means, and "what the nurse wanted to add" is
    // not one.
    row.item as it where (linkId = 'reading/changes') then {
      it.answer first as a then {
        a.value as txt ->  obs.note as n,  n.text = txt "text";
      };
    } "note";
    row.item as it where (linkId = 'reading/remarks') then {
      it.answer first as a then {
        a.value as txt ->  obs.note as n,  n.text = txt "text";
      };
    } "note2";
  } "cpapReading";
}

// ─────────────────────────────────────────────────────────────────────────────
// 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 SetExamCategory(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 = 'exam' "categoryCode";
      qr -> coding.display = 'Exam' "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 = 'cpap-monitoring-chart' "provenanceCode";
      qr -> t.display = 'CPAP monitoring chart' "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";
}