From 2da7ea088161e844e36d27bcce66684c0a567fd1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marc-Andr=C3=A9=20Bombeck?= <mbombeck@gmail.com>
Date: Sun, 14 Jun 2026 21:23:55 +0200
Subject: [PATCH] Derive recovery rank from the source-priority ladder

---
 .../__tests__/recovery-resolve.test.ts        | 23 ++++++++++++++++++
 src/lib/insights/derived/recovery-resolve.ts  | 24 +++++++++----------
 2 files changed, 34 insertions(+), 13 deletions(-)

diff --git a/src/lib/insights/derived/__tests__/recovery-resolve.test.ts b/src/lib/insights/derived/__tests__/recovery-resolve.test.ts
index b393ee458..df9487738 100644
--- a/src/lib/insights/derived/__tests__/recovery-resolve.test.ts
+++ b/src/lib/insights/derived/__tests__/recovery-resolve.test.ts
@@ -3,6 +3,7 @@ import {
   resolveCanonicalRecovery,
   type RecoveryRow,
 } from "../recovery-resolve";
+import { DEFAULT_SOURCE_PRIORITY } from "@/lib/validations/source-priority";
 
 function row(iso: string, value: number, source: string): RecoveryRow {
   return { value, measuredAt: new Date(iso), source: source as never };
@@ -116,4 +117,26 @@ describe("resolveCanonicalRecovery", () => {
   it("returns an empty list for no rows", () => {
     expect(resolveCanonicalRecovery([])).toEqual([]);
   });
+
+  // The per-source authority is derived from `DEFAULT_SOURCE_PRIORITY.recovery`
+  // (one ordered ladder), not a second hardcoded rank map. For every adjacent
+  // pair on that ladder the earlier source must win the same night, proving the
+  // resolution order tracks the ladder rather than a copy of it.
+  it("resolves in the order of DEFAULT_SOURCE_PRIORITY.recovery", () => {
+    const ladder = DEFAULT_SOURCE_PRIORITY.recovery;
+    for (let i = 0; i < ladder.length - 1; i++) {
+      const higher = ladder[i];
+      const lower = ladder[i + 1];
+      // COMPUTED carries the day-that-ended stamp; everything else stamps the
+      // wake morning. Stamp both for the SAME wake day so they collide.
+      const stampFor = (src: string) =>
+        src === "COMPUTED" ? "2026-06-01T12:00:00Z" : "2026-06-02T06:00:00Z";
+      const resolved = resolveCanonicalRecovery([
+        row(stampFor(lower), 10, lower),
+        row(stampFor(higher), 90, higher),
+      ]);
+      expect(resolved).toHaveLength(1);
+      expect(resolved[0].source).toBe(higher);
+    }
+  });
 });
diff --git a/src/lib/insights/derived/recovery-resolve.ts b/src/lib/insights/derived/recovery-resolve.ts
index 4f8c8cfed..b87298301 100644
--- a/src/lib/insights/derived/recovery-resolve.ts
+++ b/src/lib/insights/derived/recovery-resolve.ts
@@ -41,6 +41,7 @@
 import type { MeasurementSource } from "@/generated/prisma/client";
 import { dayKeyForUserTz } from "@/lib/measurements/consolidation-tz";
 import { resolveUserTimezone } from "@/lib/measurements/consolidation-base";
+import { DEFAULT_SOURCE_PRIORITY } from "@/lib/validations/source-priority";
 
 const MS_PER_DAY = 24 * 60 * 60 * 1000;
 
@@ -53,22 +54,19 @@ export interface RecoveryRow {
 
 /**
  * The per-source preference for `RECOVERY_SCORE`: a native device row outranks
- * the COMPUTED proxy for the same day. Lower number = higher authority. The
- * ladder mirrors `DEFAULT_SOURCE_PRIORITY.recovery`
- * (`WHOOP > OURA > POLAR > COMPUTED`): WHOOP's all-night strap leads, then the
- * Oura ring readiness and the Polar Nightly Recharge band, then the computed
- * proxy as the fallback for users without a wearable. A source not listed falls
- * below all of them.
+ * the COMPUTED proxy for the same day. Authority is read straight off
+ * `DEFAULT_SOURCE_PRIORITY.recovery` (`WHOOP > OURA > POLAR > COMPUTED`) — that
+ * ordered ladder is the single source of truth, so adding a recovery source
+ * updates only the priority list and this resolver inherits the new rank for
+ * free. WHOOP's all-night strap leads, then the Oura ring readiness and the
+ * Polar Nightly Recharge band, then the computed proxy as the fallback for
+ * users without a wearable. A source not on the ladder falls below all of them.
  */
-const RECOVERY_SOURCE_RANK: Partial<Record<MeasurementSource, number>> = {
-  WHOOP: 0,
-  OURA: 1,
-  POLAR: 2,
-  COMPUTED: 3,
-};
+const RECOVERY_LADDER = DEFAULT_SOURCE_PRIORITY.recovery;
 
 function rankOf(source: MeasurementSource): number {
-  return RECOVERY_SOURCE_RANK[source] ?? Number.MAX_SAFE_INTEGER;
+  const idx = RECOVERY_LADDER.indexOf(source);
+  return idx === -1 ? Number.MAX_SAFE_INTEGER : idx;
 }
 
 /**