feat: let a day already gone be ticked

People play at midnight and tick at breakfast, or forget for a week and come
back. A log that only accepts today goes wrong on its first bad evening and is
never trusted again.

An event whose end was published already allowed this — its checklist draws the
whole run and past pips are clickable. `catchUpDays` answers the two cases
`dailyDays` cannot: a standing chore, which has no start or end because it is a
routine rather than an event, and an event with `endsAt: null`, where the
checklist could draw no run at all and so offered only today. That second one
is the worse of the two, because it looks like a working checklist.

Never a day past today. A tick claims you did it, and nobody can have done
tomorrow, so a future day is absent rather than rendered and disabled — a
control for a claim that cannot be true. An event's strip starts when the event
did, capped at the same fortnight so a login campaign that opened in March does
not become a wall of pips.

The window bounds display and never data: a tick older than it stays logged and
keeps counting toward the streak. `DayPip` moves to its own module rather than
being copied, so there is one answer to what a missed day looks like.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

src/client/components/DailyChecklist.tsx

@@ -1,9 +1,12 @@
 import {
+  CATCH_UP_DAYS,
+  catchUpDays,
   dailySummary,
   msUntilReset,
   type DailySummary,
 } from "../../shared/daily.ts";
 import type { LaneId } from "../../shared/custom.ts";
+import { DayPip } from "./DayPip.tsx";
 import type { Region } from "../../shared/schema.ts";
 import { formatRemaining } from "../../shared/time.ts";
 
@@ -95,10 +98,30 @@ export function DailyChecklist({
       </button>
 
       {days === null ? (
-        <p className="mt-3 text-xs leading-relaxed text-faint">
+        <>
+          {/* No published end means no run to draw, but the days already gone
+              are just as claimable as an announced event's — and until this
+              existed they were unreachable, so a reader who forgot to tick
+              yesterday could never say so. Only the past, and only as far back
+              as `catchUpDays` goes. */}
+          <div className="mt-3 flex flex-wrap gap-1">
+            {catchUpDays(now, region, game, startsMs).map((day) => (
+              <DayPip
+                key={day}
+                day={day}
+                today={today}
+                done={logged.includes(day)}
+                onToggle={() => onToggleDay(day)}
+              />
+            ))}
+          </div>
+          <p className="mt-2.5 text-xs leading-relaxed text-faint">
             The source hasn't announced an end date, so how many days are left is
-          unknown. Your ticks are still counted — {summary.logged} so far.
+            unknown. Your ticks are still counted — {summary.logged} so far, and
+            the last {CATCH_UP_DAYS} days are above if you did one and forgot to
+            say.
           </p>
+        </>
       ) : (
         <>
           <div className="mt-3 flex flex-wrap gap-1">
@@ -121,57 +144,6 @@ export function DailyChecklist({
   );
 }
 
-/**
- * One day. Future days are dimmed but not disabled-looking, past misses read as
- * empty rather than as an error — a missed daily is information, not a telling
- * off.
- */
-function DayPip({
-  day,
-  today,
-  done,
-  onToggle,
-}: {
-  day: string;
-  today: string;
-  done: boolean;
-  onToggle: () => void;
-}) {
-  const isToday = day === today;
-  const isFuture = day > today;
-  // Rendered in UTC on purpose. A day key is a game-day, not an instant, and
-  // formatting it in the reader's own zone shifts it a day backwards for
-  // everyone west of UTC — so the pip would read "12" while the label a screen
-  // reader announces said "Aug 11".
-  const label = new Date(`${day}T00:00:00Z`).toLocaleDateString(undefined, {
-    day: "numeric",
-    month: "short",
-    timeZone: "UTC",
-  });
-
-  return (
-    <button
-      type="button"
-      onClick={onToggle}
-      disabled={isFuture}
-      aria-pressed={done}
-      aria-label={`${label}${done ? ", done" : ", not done"}`}
-      title={label}
-      className={`tnum size-6 rounded-[5px] border text-[0.625rem] leading-none transition-colors ${
-        done
-          ? "border-transparent bg-near/25 text-near"
-          : isFuture
-            ? "border-hairline/60 text-faint/50"
-            : "border-hairline text-faint hover:border-faint"
-      } ${isToday ? "ring-1 ring-ink/40" : ""} ${
-        isFuture ? "cursor-default" : "cursor-pointer"
-      }`}
-    >
-      {day.slice(8)}
-    </button>
-  );
-}
-
 function caption(summary: DailySummary, todayInWindow: boolean): string {
   const { days, logged, remaining, missed } = summary;
   if (days === null || remaining === null) return `${logged} days ticked off.`;

src/client/components/DayPip.tsx

@@ -0,0 +1,59 @@
+/**
+ * One game-day, ticked or not.
+ *
+ * Shared by the two places a run of days is drawn: an event's checklist in the
+ * detail sheet, and the catch-up strips on the dailies section and on an event
+ * whose end was never announced. One pip rather than two, because they mean the
+ * same thing to the reader and a second copy is a second set of rules about
+ * what a missed day looks like.
+ *
+ * Future days are dimmed but not disabled-looking, and past misses read as
+ * empty rather than as an error — a missed daily is information, not a telling
+ * off. A catch-up strip never contains a future day at all, so there the
+ * dimming never appears.
+ */
+export function DayPip({
+  day,
+  today,
+  done,
+  onToggle,
+}: {
+  day: string;
+  today: string;
+  done: boolean;
+  onToggle: () => void;
+}) {
+  const isToday = day === today;
+  const isFuture = day > today;
+  // Rendered in UTC on purpose. A day key is a game-day, not an instant, and
+  // formatting it in the reader's own zone shifts it a day backwards for
+  // everyone west of UTC — so the pip would read "12" while the label a screen
+  // reader announces said "Aug 11".
+  const label = new Date(`${day}T00:00:00Z`).toLocaleDateString(undefined, {
+    day: "numeric",
+    month: "short",
+    timeZone: "UTC",
+  });
+
+  return (
+    <button
+      type="button"
+      onClick={onToggle}
+      disabled={isFuture}
+      aria-pressed={done}
+      aria-label={`${label}${done ? ", done" : ", not done"}`}
+      title={label}
+      className={`tnum size-6 rounded-[5px] border text-[0.625rem] leading-none transition-colors ${
+        done
+          ? "border-transparent bg-near/25 text-near"
+          : isFuture
+            ? "border-hairline/60 text-faint/50"
+            : "border-hairline text-faint hover:border-faint"
+      } ${isToday ? "ring-1 ring-ink/40" : ""} ${
+        isFuture ? "cursor-default" : "cursor-pointer"
+      }`}
+    >
+      {day.slice(8)}
+    </button>
+  );
+}

src/shared/daily.ts

@@ -161,6 +161,59 @@ export function dailyDays(
   return out;
 }
 
+/**
+ * How far back a catch-up strip reaches.
+ *
+ * A fortnight: long enough to repair a holiday or a bad week, short enough that
+ * it is still recording what you did rather than reconstructing a month from
+ * memory. It bounds *display* only — see `catchUpDays`.
+ */
+export const CATCH_UP_DAYS = 14;
+
+/**
+ * The days a reader can still say they did, oldest first.
+ *
+ * `dailyDays` answers this for an event whose end was announced, because there
+ * the whole run is known. Two things it cannot answer: a game's standing chore,
+ * which has no start and no end because it is a routine rather than an event,
+ * and an event with `endsAt: null`, where `dailyDays` returns null and the
+ * checklist has nothing to draw. Both leave the reader with today and no way to
+ * record yesterday, which is the day they actually did and forgot to tick.
+ *
+ * `notBefore` is an instant to clip at — an event's start — or null when there
+ * is nothing to clip at, which is the chore case. Never returns a day past
+ * today: a tick is a claim you did it, and tomorrow is not something anyone can
+ * have done, so it is absent rather than present-and-disabled.
+ *
+ * **This bounds what is shown and never what is stored.** A tick older than the
+ * window stays in the log, keeps counting toward `streakOf` and toward
+ * `dailySummary`'s totals, and is simply off-screen — nothing here removes a day
+ * the reader did not remove themselves.
+ */
+export function catchUpDays(
+  now: number,
+  region: Region,
+  game: LaneId | undefined,
+  notBefore: number | null,
+  span = CATCH_UP_DAYS,
+): string[] {
+  const today = dayKey(now, region, game);
+  const floor = notBefore === null ? null : dayKey(notBefore, region, game);
+
+  const out: string[] = [];
+  // Walked in day-key space rather than in instants, like `streakOf`: these are
+  // keys cut on a game's reset clock, and stepping a calendar day back is the
+  // only operation that keeps them lined up with what was written.
+  let cursor = Date.parse(`${today}T00:00:00Z`);
+  while (out.length < span) {
+    const key = keyOf(cursor);
+    if (floor !== null && key < floor) break;
+    out.push(key);
+    cursor -= DAY;
+  }
+  return out.reverse();
+}
+
 export interface DailySummary {
   /** Every claimable day, oldest first. Null when the end is unannounced. */
   days: string[] | null;

test/daily.test.ts

@@ -1,5 +1,7 @@
 import { describe, expect, test } from "bun:test";
 import {
+  catchUpDays,
+  CATCH_UP_DAYS,
   dailiesId,
   dailyDays,
   dailyOverride,
@@ -408,3 +410,87 @@ describe("a game whose day rolls on a different hour", () => {
     ]);
   });
 });
+
+describe("catchUpDays", () => {
+  const NOW = at("2026-08-20T12:00:00.000Z");
+
+  test("the last fortnight, oldest first, ending today", () => {
+    const days = catchUpDays(NOW, "europe", "genshin", null);
+    expect(days).toHaveLength(CATCH_UP_DAYS);
+    expect(days[days.length - 1]).toBe(dayKey(NOW, "europe", "genshin"));
+    expect(days[0]).toBe(dayKey(NOW - 13 * DAY, "europe", "genshin"));
+    expect([...days].sort()).toEqual(days);
+  });
+
+  test("never a day past today", () => {
+    // A tick is a claim that you did it. Tomorrow is not a thing a reader can
+    // have done, so it is not rendered at all rather than rendered and disabled.
+    const days = catchUpDays(NOW, "europe", "genshin", null);
+    const today = dayKey(NOW, "europe", "genshin");
+    expect(days.filter((d) => d > today)).toEqual([]);
+  });
+
+  test("stops at the day the event began", () => {
+    // An event that opened three days ago has three days to catch up on, not
+    // fourteen — the days before it existed were never claimable.
+    const started = NOW - 2 * DAY;
+    const days = catchUpDays(NOW, "europe", "genshin", started);
+    expect(days).toEqual([
+      dayKey(started, "europe", "genshin"),
+      dayKey(NOW - DAY, "europe", "genshin"),
+      dayKey(NOW, "europe", "genshin"),
+    ]);
+  });
+
+  test("a long-running event is still capped at the fortnight", () => {
+    // A standing login campaign can have opened half a year ago. Its whole
+    // history would be a wall of pips nobody scrolls, and reconstructing March
+    // from memory is not recording what you did.
+    const days = catchUpDays(NOW, "europe", "genshin", NOW - 200 * DAY);
+    expect(days).toHaveLength(CATCH_UP_DAYS);
+  });
+
+  test("an event that has not started yet offers nothing", () => {
+    expect(catchUpDays(NOW, "europe", "genshin", NOW + 3 * DAY)).toEqual([]);
+  });
+
+  test("cut on the game's own reset clock, not the region's", () => {
+    // Endfield serves Europe off the Americas machine, so its European day
+    // rolls at 09:00 UTC rather than 03:00 — a strip cut on the wrong clock
+    // writes a tick under one day key and reads it under another.
+    const dawn = at("2026-08-20T05:00:00.000Z");
+    const generic = catchUpDays(dawn, "europe", undefined, null);
+    const endfield = catchUpDays(dawn, "europe", "endfield", null);
+    expect(endfield).not.toEqual(generic);
+    expect(endfield[endfield.length - 1]).toBe(dayKey(dawn, "europe", "endfield"));
+  });
+
+  test("the window bounds what is shown and never what is stored", () => {
+    // A tick from five weeks ago is off-screen, still logged, and still counted.
+    // Nothing here removes a day the reader did not remove themselves.
+    const old = dayKey(NOW - 35 * DAY, "europe", "genshin");
+    const days = catchUpDays(NOW, "europe", "genshin", null);
+    expect(days).not.toContain(old);
+
+    const logged = [old, dayKey(NOW, "europe", "genshin")];
+    const summary = dailySummary({
+      startsMs: NOW - 40 * DAY,
+      endsMs: null,
+      region: "europe",
+      game: "genshin",
+      now: NOW,
+      logged,
+    });
+    expect(summary.logged).toBe(2);
+    expect(summary.doneToday).toBe(true);
+  });
+
+  test("a streak built outside the window still counts", () => {
+    const today = dayKey(NOW, "europe", "genshin");
+    const logged = Array.from({ length: 30 }, (_, i) =>
+      dayKey(NOW - i * DAY, "europe", "genshin"),
+    );
+    expect(streakOf(logged, today)).toBe(30);
+    expect(catchUpDays(NOW, "europe", "genshin", null)).toHaveLength(CATCH_UP_DAYS);
+  });
+});