From 56bc46417e278ae1f8101378c919f1af91d377b5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marc-Andr=C3=A9=20Bombeck?= <mbombeck@gmail.com>
Date: Mon, 8 Jun 2026 17:30:31 +0200
Subject: [PATCH] =?UTF-8?q?fix(medications):=20keep=20degenerate=20?=
 =?UTF-8?q?=E2=89=A41-day=20rolling=20on=20the=20minute=20scale?=
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Self-review: a rolling interval of 1 day is effectively daily, so a ±1-day
day-scale on-time window would over-widen and let one take claim adjacent
slots. Classify rolling by its interval — ≥2 days is day-scale (the canonical
weekly+ injection), ≤1 day stays minute-scale. Two tests pin the distinction.
---
 .../scheduling/__tests__/band-minter.test.ts  | 30 +++++++++++++++++++
 src/lib/medications/scheduling/band-minter.ts | 12 ++++++--
 2 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/src/lib/medications/scheduling/__tests__/band-minter.test.ts b/src/lib/medications/scheduling/__tests__/band-minter.test.ts
index af94cfdd2..e2975302f 100644
--- a/src/lib/medications/scheduling/__tests__/band-minter.test.ts
+++ b/src/lib/medications/scheduling/__tests__/band-minter.test.ts
@@ -224,6 +224,36 @@ describe("rolling GLP-1 (every 7 days) — retrospective bands", () => {
   });
 });
 
+describe("rolling — a ≤1-day interval stays minute-scale (daily family)", () => {
+  // A degenerate every-1-day rolling interval is effectively daily; a ±1-day
+  // on-time window would over-widen, so it must classify daily (minute-scale).
+  const m = med({ startsOn: new Date("2026-06-01T00:00:00Z") });
+  const sched = schedule({ rollingIntervalDays: 1, timesOfDay: ["08:00"] });
+  const shot = new Date("2026-06-08T08:05:00Z");
+  const out = buildBandsForMedication({
+    medication: m,
+    schedule: sched,
+    ctx: ctxFor(m, shot),
+    userTz: TZ,
+    range: {
+      from: new Date("2026-06-07T00:00:00Z"),
+      to: new Date("2026-06-09T00:00:00Z"),
+    },
+    now: new Date("2026-06-09T00:00:00Z"),
+    intakeInstants: [shot],
+  });
+
+  it("uses the daily family for a 1-day rolling cadence", () => {
+    expect(out.family).toBe("daily");
+  });
+
+  it("the on-time band is minute-scale (±60min), not day-scale", () => {
+    const b = out.bands[0];
+    const span = b.onTimeEnd.getTime() - b.onTimeStart.getTime();
+    expect(span).toBe(2 * 60 * MIN);
+  });
+});
+
 // ────────────────────────────────────────────────────────────────────
 // 4. Cyclic (on/off weeks)
 // ────────────────────────────────────────────────────────────────────
diff --git a/src/lib/medications/scheduling/band-minter.ts b/src/lib/medications/scheduling/band-minter.ts
index d7e44f7ac..4d62ba424 100644
--- a/src/lib/medications/scheduling/band-minter.ts
+++ b/src/lib/medications/scheduling/band-minter.ts
@@ -165,9 +165,15 @@ export function buildBandsForMedication(
       input.intakeInstants ?? [],
       now,
     );
-    // Rolling is inherently day-scale (every-N-days). Mint day-scale bands.
-    const bands = mintBands(occ, "weekly", input.windowConfig, userTz);
-    return { bands, hasExpectedSlots: true, family: "weekly" };
+    // The canonical rolling case is a once-weekly+ injection (day-scale). A
+    // degenerate ≤1-day rolling interval is effectively daily, so a ±1-day
+    // on-time window would over-widen and let one take claim adjacent slots —
+    // keep it minute-scale. The realised every-N-days cadence is the field
+    // here (intakes drive the anchors), so the interval is the right signal.
+    const family: "daily" | "weekly" =
+      schedule.rollingIntervalDays >= 2 ? "weekly" : "daily";
+    const bands = mintBands(occ, family, input.windowConfig, userTz);
+    return { bands, hasExpectedSlots: true, family };
   }
 
   // Daily / weekly / cyclic / rrule — `occurrencesBetween` already filters