From a411d593052004432ac5aa5b02265866a04dd0b1 Mon Sep 17 00:00:00 2001
From: Experiments DB Dev <dev@experiments-db.local>
Date: Sun, 19 Jul 2026 13:16:33 -0400
Subject: [PATCH] feat(export): dimension primitives, date members, status
 index

---
 frontend/src/lib/dataExport.js    | 48 +++++++++++++++++++++++
 frontend/tests/dataExport.test.js | 65 +++++++++++++++++++++++++++++++
 2 files changed, 113 insertions(+)

diff --git a/frontend/src/lib/dataExport.js b/frontend/src/lib/dataExport.js
index d32649a..46e2ff1 100644
--- a/frontend/src/lib/dataExport.js
+++ b/frontend/src/lib/dataExport.js
@@ -54,6 +54,54 @@ export function listExportableParams(dailyTemplate, statuses) {
   return params;
 }
 
+export const EXPORT_DIMENSIONS = [
+  { dim: 'date', label: 'Date' },
+  { dim: 'subject', label: 'Subject' },
+  { dim: 'parameter', label: 'Parameter' },
+];
+
+export function dimLabel(dim) {
+  return EXPORT_DIMENSIONS.find((d) => d.dim === dim)?.label ?? '';
+}
+
+export function otherDimension(rowDim, colDim) {
+  return EXPORT_DIMENSIONS.map((d) => d.dim).find((d) => d !== rowDim && d !== colDim) ?? null;
+}
+
+// Resolve a subject's group value for a given group field id.
+// null  -> no grouping (field is falsy or '__none__')
+// '—'   -> grouping is on but this subject has no value
+export function subjectGroupValue(animal, groupField) {
+  if (!groupField || groupField === '__none__') return null;
+  if (groupField === '__name__') return animal?.animal_name ?? '—';
+  if (groupField === '__id__') return animal?.animal_id_string ?? '—';
+  const v = animal?.subject_info?.[groupField];
+  return v === null || v === undefined || v === '' ? '—' : v;
+}
+
+export function listDateMembers(statuses) {
+  const keys = new Set();
+  for (const s of statuses ?? []) {
+    if (s?.date) keys.add(dateKey(s.date));
+  }
+  return [...keys].sort().map((k) => ({ id: k, label: k, dateKey: k }));
+}
+
+// dateKey -> Map(animalId -> status); first status per (date, animal) wins,
+// scanning in date order (matches the legacy buildMatrix tie-break).
+export function buildStatusIndex(statuses) {
+  const index = new Map();
+  const ordered = [...(statuses ?? [])].sort((a, b) => dateKey(a?.date).localeCompare(dateKey(b?.date)));
+  for (const s of ordered) {
+    if (!s?.date || s.animal_id === null || s.animal_id === undefined) continue;
+    const dk = dateKey(s.date);
+    if (!index.has(dk)) index.set(dk, new Map());
+    const byAnimal = index.get(dk);
+    if (!byAnimal.has(s.animal_id)) byAnimal.set(s.animal_id, s);
+  }
+  return index;
+}
+
 // A cell has a value unless it is null, undefined, or the empty string.
 // (0 and false are real values.)
 function hasValue(v) {
diff --git a/frontend/tests/dataExport.test.js b/frontend/tests/dataExport.test.js
index 4f01f2a..fba143b 100644
--- a/frontend/tests/dataExport.test.js
+++ b/frontend/tests/dataExport.test.js
@@ -155,3 +155,68 @@ describe('csvFilename', () => {
     expect(csvFilename('', '')).toBe('export.csv');
   });
 });
+
+import {
+  EXPORT_DIMENSIONS, dimLabel, otherDimension, subjectGroupValue,
+  listDateMembers, buildStatusIndex,
+} from '../src/lib/dataExport';
+
+describe('dimension primitives', () => {
+  it('exposes the three dimensions with labels', () => {
+    expect(EXPORT_DIMENSIONS.map((d) => d.dim)).toEqual(['date', 'subject', 'parameter']);
+    expect(dimLabel('date')).toBe('Date');
+    expect(dimLabel('subject')).toBe('Subject');
+    expect(dimLabel('parameter')).toBe('Parameter');
+  });
+  it('otherDimension returns the leftover', () => {
+    expect(otherDimension('date', 'subject')).toBe('parameter');
+    expect(otherDimension('parameter', 'date')).toBe('subject');
+  });
+});
+
+describe('subjectGroupValue', () => {
+  const animal = { animal_name: 'Alpha', animal_id_string: 'R-001', subject_info: { sex: 'M', cohort: '' } };
+  it('returns null when no group field', () => {
+    expect(subjectGroupValue(animal, '__none__')).toBeNull();
+    expect(subjectGroupValue(animal, '')).toBeNull();
+  });
+  it('resolves name / id / subject_info fields', () => {
+    expect(subjectGroupValue(animal, '__name__')).toBe('Alpha');
+    expect(subjectGroupValue(animal, '__id__')).toBe('R-001');
+    expect(subjectGroupValue(animal, 'sex')).toBe('M');
+  });
+  it('renders missing or empty values as an em dash', () => {
+    expect(subjectGroupValue(animal, 'cohort')).toBe('—');
+    expect(subjectGroupValue({}, 'sex')).toBe('—');
+  });
+});
+
+describe('listDateMembers', () => {
+  it('returns sorted unique dateKeys with id/label', () => {
+    const statuses = [
+      { date: '2026-07-02T00:00:00.000Z' },
+      { date: '2026-07-01T12:00:00.000Z' },
+      { date: '2026-07-02T09:00:00.000Z' },
+    ];
+    expect(listDateMembers(statuses)).toEqual([
+      { id: '2026-07-01', label: '2026-07-01', dateKey: '2026-07-01' },
+      { id: '2026-07-02', label: '2026-07-02', dateKey: '2026-07-02' },
+    ]);
+  });
+  it('tolerates empty input', () => {
+    expect(listDateMembers(undefined)).toEqual([]);
+  });
+});
+
+describe('buildStatusIndex', () => {
+  it('indexes by dateKey then animalId, first status wins', () => {
+    const statuses = [
+      { animal_id: 'a1', date: '2026-07-01T00:00:00.000Z', analysis_summary: { total: 7 } },
+      { animal_id: 'a1', date: '2026-07-01T06:00:00.000Z', analysis_summary: { total: 99 } },
+      { animal_id: 'a2', date: '2026-07-01T00:00:00.000Z', analysis_summary: { total: 3 } },
+    ];
+    const idx = buildStatusIndex(statuses);
+    expect(idx.get('2026-07-01').get('a1').analysis_summary.total).toBe(7);
+    expect(idx.get('2026-07-01').get('a2').analysis_summary.total).toBe(3);
+  });
+});