/// url = 'https://fhir.slade360.co.ke/fhir/StructureMap/ExtractMilkFeedingChart'
/// name = 'ExtractMilkFeedingChart'
/// title = 'Milk Feeding Chart Extraction'
/// status = 'active'
/// description = 'A NutritionIntake per feed carrying what was given and how much, plus an Observation panel for the row\'s target, what was retained and the diaper. The retained volume is the point: the difference between given and retained is what says whether a baby is tolerating feeds, and a chart that only records what was offered cannot answer that.'

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
uses "http://hl7.org/fhir/StructureDefinition/NutritionIntake" alias NutritionIntake as target

group ExtractMilkFeedingChart(source qr : QR, target bundle : Bundle) {
  qr -> bundle.type = 'transaction' "setBundleType";
  qr.item as row where ((linkId = 'feed') and item.where(linkId = 'feed/amount-given').answer.value.exists()) then {
    // ── What was given ────────────────────────────────────────────────────
    row ->  bundle.entry as entry,  entry.resource = create('NutritionIntake') as ni then {
      qr ->  ni,  entry then BuildNutritionIntakeBase(qr, ni, entry) "base";
      row -> ni.status = 'completed' "status";
      qr.encounter as e -> ni.encounter = e;
      row.item as it where ((linkId = 'feed/at') and answer.value.exists()) then {
        it.answer first as a then {
          a.value as v -> ni.occurrence = v "occurrence";
        };
      } "atRule";
      // One rule, not three. NutritionIntake.consumedItem requires both `type`
      // and `nutritionProduct` at 1..1, and building the element from separate
      // rules produced a consumedItem carrying only an amount -- which
      // compiles, extracts, and then fails validation twice over.
      // `type` takes a local concept code. Its binding is example-strength and
      // the obvious candidate, diet-type#formula, does not resolve on this
      // server; a code that cannot be looked up is worse than one that says
      // exactly what the chart's column says.
      row -> ni.consumedItem as ci then {
        row -> ci.type as ct then {
          row -> ct.coding as cg then {
            row -> cg.system = 'https://fhir.slade360.co.ke/fhir/CodeSystem/concept-codesystem' "sys";
            row -> cg.code = 'feeding-milk-feed' "cd";
            row -> cg.display = 'Milk feed' "dsp";
          } "coding";
        } "type";
        row.item as it where ((linkId = 'feed/type') and answer.value.exists()) then {
          it.answer first as a then {
            a.value as cv ->  ci.nutritionProduct = create('CodeableReference') as npr,  npr.concept as npc then {
              cv -> npc.coding = cv "coding";
              cv.display as d -> npc.text = d "text";
            } "product";
          };
        } "typeRule";
        // nutritionProduct is also 1..1, so where the chart's type column was
        // left blank it still has to say something. "Milk feed, type not
        // recorded" is the honest filler.
        row where (item.where(linkId = 'feed/type').answer.value.exists().not()) ->  ci.nutritionProduct = create('CodeableReference') as npr,  npr.concept as npc,  npc.text = 'Milk feed, type not recorded on the chart' "productFallback";
        row.item as it where ((linkId = 'feed/amount-given') and answer.value.ofType(Quantity).exists()) then {
          it.answer first as a then {
            a.value as v -> ci.amount = v "amount";
          };
        } "amountRule";
      } "consumedItem";
      row.item as it where ((linkId = 'feed/given-by') and answer.value.exists()) then {
        it.answer first as a then {
          a.value as ref ->  ni.performer as p,  p.actor = ref "performer";
        };
      } "byRule";
    } "feedIntake";
    // ── Target, retained and diaper ───────────────────────────────────────
    row ->  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 = 'https://fhir.slade360.co.ke/fhir/CodeSystem/concept-codesystem' "sys";
          row -> cg.code = 'feeding-milk-feed-record' "cd";
          row -> cg.display = 'Milk feed record' "dsp";
        } "coding";
      } "code";
      row.item as it where ((linkId = 'feed/three-hourly-target') and answer.value.exists()) -> obs.component as comp then {
        it -> comp.code as cc then {
          it -> cc.coding as cg then {
            it -> cg.system = 'https://fhir.slade360.co.ke/fhir/CodeSystem/concept-codesystem' "sys";
            it -> cg.code = 'feeding-three-hourly-feed-target' "cd";
            it -> cg.display = 'Three-hourly feed target' "dsp";
          } "coding";
        } "code";
        it -> comp then SetComponentValue(it, comp) "value";
      } "comp_feeding_three_hourly_feed_target";
      row.item as it where ((linkId = 'feed/amount-given') and answer.value.exists()) -> obs.component as comp then {
        it -> comp.code as cc then {
          it -> cc.coding as cg then {
            it -> cg.system = 'https://fhir.slade360.co.ke/fhir/CodeSystem/concept-codesystem' "sys";
            it -> cg.code = 'feeding-feed-volume-given' "cd";
            it -> cg.display = 'Feed volume given' "dsp";
          } "coding";
        } "code";
        it -> comp then SetComponentValue(it, comp) "value";
      } "comp_feeding_feed_volume_given";
      row.item as it where ((linkId = 'feed/retained') and answer.value.exists()) -> obs.component as comp then {
        it -> comp.code as cc then {
          it -> cc.coding as cg then {
            it -> cg.system = 'https://fhir.slade360.co.ke/fhir/CodeSystem/concept-codesystem' "sys";
            it -> cg.code = 'feeding-feed-volume-retained' "cd";
            it -> cg.display = 'Feed volume retained' "dsp";
          } "coding";
        } "code";
        it -> comp then SetComponentValue(it, comp) "value";
      } "comp_feeding_feed_volume_retained";
      row.item as diaper where (linkId = 'feed/diaper') then {
        diaper.item as it where ((linkId = 'feed/diaper/stool') and answer.value.exists()) -> obs.component as comp then {
          it -> comp.code as cc then {
            it -> cc.coding as cg then {
              it -> cg.system = 'https://fhir.slade360.co.ke/fhir/CodeSystem/concept-codesystem' "sys";
              it -> cg.code = 'feeding-passed-stool' "cd";
              it -> cg.display = 'Passed stool' "dsp";
            } "coding";
          } "code";
          it -> comp then SetComponentCodedValue(it, comp) "value";
        } "comp_feeding_passed_stool";
        diaper.item as it where ((linkId = 'feed/diaper/urine') and answer.value.exists()) -> obs.component as comp then {
          it -> comp.code as cc then {
            it -> cc.coding as cg then {
              it -> cg.system = 'https://fhir.slade360.co.ke/fhir/CodeSystem/concept-codesystem' "sys";
              it -> cg.code = 'feeding-passed-urine' "cd";
              it -> cg.display = 'Passed urine' "dsp";
            } "coding";
          } "code";
          it -> comp then SetComponentCodedValue(it, comp) "value";
        } "comp_feeding_passed_urine";
      } "FeedDiaperGroup";
      row -> obs then SetFeedRowTime(row, obs) "rowTime";
    } "feedObservation";
  } "feedRows";
}

// The row's own timestamp on everything extracted from that row.
group SetFeedRowTime(source row, target obs : Observation) {
  row.item as it where ((linkId = 'feed/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 = 'feed/given-by') 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";
}

group BuildNutritionIntakeBase(source qr : QR, target r : NutritionIntake, target entry) {
  qr -> r then SetResponseProvenance(qr, r) "responseProvenance";
  qr -> r.id = uuid() then SetNutritionIntakeFullUrl(r, entry) "idAndFullUrl";
  qr -> entry.request as request then {
    qr -> request.method = 'POST' "requestMethod";
    qr -> request.url = 'NutritionIntake' "requestUrl";
  } "entryRequest";
  qr.subject as s -> r.subject = s;
}

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

// ── 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 = 'milk-feeding-chart' "provenanceCode";
      qr -> t.display = 'Milk feeding 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";
}