feat(frontend): listExportableParams enumerates export options

frontend/src/lib/dataExport.js

@@ -21,3 +21,35 @@ export function extractValue(status, param) {
       return null;
   }
 }
+
+// Build the grouped, ordered list of exportable parameters.
+// Session metrics (total, success_rate, then each dynamic count category found
+// in the data) come first; then every field defined in the daily template,
+// including inactive ones (historical data may exist).
+export function listExportableParams(dailyTemplate, statuses) {
+  const params = [
+    { id: '__total__', label: 'Total attempts', group: 'metrics', kind: 'total' },
+    { id: '__success_rate__', label: 'Success rate', group: 'metrics', kind: 'success_rate' },
+  ];
+
+  const cats = new Set();
+  for (const s of statuses ?? []) {
+    const counts = s?.analysis_summary?.counts;
+    if (counts && typeof counts === 'object') {
+      for (const k of Object.keys(counts)) cats.add(k);
+    }
+  }
+  for (const cat of [...cats].sort()) {
+    params.push({ id: `__cat__${cat}`, label: cat, group: 'metrics', kind: 'category', category: cat });
+  }
+
+  for (const f of dailyTemplate ?? []) {
+    if (f.builtin) {
+      params.push({ id: `b:${f.fieldId}`, label: f.label, group: 'daily', kind: 'builtin', statusKey: f.key });
+    } else {
+      params.push({ id: `c:${f.fieldId}`, label: f.label, group: 'daily', kind: 'custom', fieldId: f.fieldId });
+    }
+  }
+
+  return params;
+}

frontend/tests/dataExport.test.js

@@ -1,4 +1,5 @@
 import { extractValue } from '../src/lib/dataExport';
+import { listExportableParams } from '../src/lib/dataExport';
 
 const status = {
   vitals: 'ok',
@@ -31,3 +32,41 @@ describe('extractValue', () => {
     expect(extractValue({}, { kind: 'builtin', statusKey: 'notes' })).toBeNull();
   });
 });
+
+const dailyTemplate = [
+  { fieldId: 'b-vitals', key: 'vitals', label: 'Vitals', builtin: true, active: true },
+  { fieldId: 'c-weight', key: 'weight', label: 'Weight (g)', builtin: false, active: false },
+];
+const statuses = [
+  { analysis_summary: { counts: { Success: 1, Failure: 0 } } },
+  { analysis_summary: { counts: { Success: 2, Other: 1 } } },
+  { analysis_summary: null },
+];
+
+describe('listExportableParams', () => {
+  const params = listExportableParams(dailyTemplate, statuses);
+  it('starts with the two fixed session metrics', () => {
+    expect(params.slice(0, 2)).toEqual([
+      expect.objectContaining({ id: '__total__', label: 'Total attempts', group: 'metrics', kind: 'total' }),
+      expect.objectContaining({ id: '__success_rate__', label: 'Success rate', group: 'metrics', kind: 'success_rate' }),
+    ]);
+  });
+  it('adds one metrics entry per dynamic count category, sorted', () => {
+    const cats = params.filter((p) => p.kind === 'category').map((p) => p.label);
+    expect(cats).toEqual(['Failure', 'Other', 'Success']);
+  });
+  it('includes every template field (incl. inactive) in the daily group', () => {
+    const daily = params.filter((p) => p.group === 'daily');
+    expect(daily).toEqual([
+      expect.objectContaining({ label: 'Vitals', kind: 'builtin', statusKey: 'vitals' }),
+      expect.objectContaining({ label: 'Weight (g)', kind: 'custom', fieldId: 'c-weight' }),
+    ]);
+  });
+  it('gives every param a unique id', () => {
+    const ids = params.map((p) => p.id);
+    expect(new Set(ids).size).toBe(ids.length);
+  });
+  it('tolerates empty/missing inputs', () => {
+    expect(listExportableParams(undefined, undefined).length).toBe(2); // just the two fixed metrics
+  });
+});