fix(daily): reset Endfield's European day on the server it's on

Endfield has two server groups, not three: Europe is served off the
Americas machine on a fixed UTC-5, so a European player's day rolls at
09:00 UTC. We were resetting it six hours early, at 03:00, which ticked
the wrong box every morning between those two instants.

Adds GameMeta.resetOffsets, a sparse per-region override, and threads an
optional `game` through every day-key function. Per region rather than
per game on purpose: a blanket offset would drag Asia — which does have
its own Endfield server — onto the Americas clock, moving day keys for
readers who never had the bug. A regression test pins Asia's output as
identical to before.

Day keys are localStorage keys, so this re-labels ticks logged between
03:00 and 09:00 UTC by European Endfield players, one day backward. No
tick is deleted and past days stay editable, but a streak can read as
broken for a day. That is the cost of correcting a wrong reset; leaving
it wrong is worse.

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

CLAUDE.md

@@ -83,7 +83,7 @@ src/client/       React app, service worker, manifest
   state/          progress, daily log, ignores, prefs, sort — all localStorage
 scripts/          build-feed.ts, parse-fixture.ts (offline), refresh-sources.ts (fetches)
 serve.ts          static server + /api/health
-test/             257 tests
+test/             301 tests
 fixtures/<game>/  raw HTML + .expected.json per source — pinned, kept forever
 snapshots/        current page per source, rewritten by refresh — see its README
 ```
@@ -150,6 +150,13 @@ Two more key spaces have the same property, for the same reason:
 - **Game-day keys** (`dayKey`) are `YYYY-MM-DD` in *server-reset space*, not UTC — the day rolls at
   04:00 local server time. They are storage keys *and* they are compared with `<` and sorted, so the
   format is fixed. Changing the reset hour or the offsets moves every reader's streak by a day.
+  A game whose server map differs lists the affected regions in `resetOffsets` (`games.ts`) —
+  Endfield serves Europe off the Americas machine, so `europe` is UTC-5 there and its reset is
+  09:00 UTC, not 03:00. Keep that override **per region**: a blanket per-game offset drags the
+  regions that do have their own server onto someone else's clock. Every day-key function takes an
+  optional `game` — **anything reading or writing a tick must pass it**, or it writes under one
+  clock and reads under another. A day that drops out of `dailyDays` renders no pip, so a tick on it
+  becomes unreachable; check real fixture windows before changing an offset.
 
 The sanitizer at the ingest boundary recomputes an event ID only when a sanitized title actually
 changed *and* the ID was minted the standard way. If a change to it starts moving IDs on real

docs/ARCHITECTURE.md

@@ -72,7 +72,7 @@ src/
   shared/
     schema.ts           zod schemas — the contract, both sides    ✓ built
     time.ts             clocks, urgency, region resets, captions  ✓ built
-    games.ts            per-game name and hue                     ✓ built
+    games.ts            per-game name, hue, and reset clock       ✓ built
     feed.ts             the /api/events.json wire contract        ✓ built
   client/                                                         ✓ all built
     main.tsx            render + service worker registration

docs/DATA-MODEL.md

@@ -243,6 +243,38 @@ server time, so a player finishing at 02:00 is still on the previous day's daili
 computed against the reader's chosen region (`RESET_HOUR_LOCAL`, `dayKey`). Keys sort
 lexicographically, which is what "how many days are left" and streak counting rely on.
 
+**Not every game has a server per region.** `GameMeta.resetOffsets` records the regions where a
+game's server clock differs from `REGION_RESET_UTC_OFFSET`. Endfield is the case this exists for: it
+has two server groups rather than three, and Europe is served off the Americas machine on a fixed
+UTC-5, so a European player's reset is 09:00 UTC — six hours after the HoYoverse/Kuro pattern.
+Every day-key function takes an optional `game` for this reason, and **anything reading or writing a
+tick must pass it**: a write under one clock and a read under another puts the tick on a day the
+reader cannot see.
+
+| Game | Reset (server local) | Server offset | Reset (UTC) | Copenhagen, summer / winter |
+|---|---|---|---|---|
+| Genshin, Star Rail, ZZZ, Wuwa, NTE | 04:00 | region (EU = UTC+1) | 03:00 | 05:00 / 04:00 |
+| Endfield, Europe | 04:00 | UTC-5 (on the Americas server) | 09:00 | 11:00 / 10:00 |
+| Endfield, Asia / Americas | 04:00 | regional default | 20:00 / 09:00 | — |
+
+These server offsets are **fixed and do not observe DST**, so the reader's local reset time moves by
+an hour across the European clock change while the UTC instant stays put.
+
+The override is deliberately **per region, not per game**. A blanket per-game offset is the wrong
+shape: it drags the regions that do have their own server onto somebody else's clock, moving day
+keys for readers who never had the bug. List only the regions that actually differ.
+
+Changing a value in that table is a **data change, not a constant change**: it re-labels the
+game-day some already-logged ticks fall in, for readers in that region. Two consequences to check
+before shipping one, both of which are invisible at runtime:
+
+- A tick logged inside the shifted window reads as the adjacent day, which can show as a one-day
+  break in a streak. Recoverable — past days stay editable.
+- If the shift moves a window's boundary, a day can drop out of `dailyDays` entirely. A day that is
+  not in `dailyDays` renders no pip, so a tick on it is **unreachable**: not deleted, but with no UI
+  path back to it and nothing server-side to recover from. Check the real fixture windows for the
+  affected game and region before changing an offset.
+
 Three rules this store keeps, for the same reason the rest of the client does — nothing else holds
 a copy:
 

src/client/App.tsx

@@ -103,6 +103,7 @@ export function App() {
       startsMs: row.clock.startsMs,
       endsMs: row.clock.endsMs,
       region: prefs.region,
+      game: row.event.game,
       now,
       logged: daily.daysFor(row.event.id),
     });

src/client/components/Dailies.tsx

@@ -35,13 +35,33 @@ export function Dailies({
   daysFor: (id: string) => string[];
   onToggleDay: (id: string, day: string) => void;
 }) {
-  if (games.length === 0 && events.length === 0) return null;
+  // Each game rolls on its own server clock, so "today" is asked per game
+  // rather than once for the section — Endfield's European day can still be
+  // yesterday's while every HoYo game has already turned over.
+  const chores = games.map((id) => ({
+    key: dailiesId(id),
+    game: gameMeta(id),
+    today: dayKey(now, region, id),
+    resetsIn: msUntilReset(now, region, id),
+  }));
+  const repeating = events.map((event) => ({
+    key: event.id,
+    event,
+    game: gameMeta(event.game),
+    today: dayKey(now, region, event.game),
+    resetsIn: msUntilReset(now, region, event.game),
+  }));
 
-  const today = dayKey(now, region);
-  const doneEvents = events.filter((e) => daysFor(e.id).includes(today));
-  const done = games.filter((g) => daysFor(dailiesId(g)).includes(today));
-  const total = games.length + events.length;
-  const complete = done.length + doneEvents.length;
+  const items = [...chores, ...repeating];
+  const total = items.length;
+  const complete = items.filter((i) => daysFor(i.key).includes(i.today)).length;
+
+  if (total === 0) return null;
+
+  // With mixed reset clocks there is no single "resets in", so the header
+  // reports the next one to land and says that it is the next one.
+  const soonest = Math.min(...items.map((i) => i.resetsIn));
+  const mixed = new Set(items.map((i) => i.resetsIn)).size > 1;
 
   return (
     <section className="border-b border-hairline px-4 py-4">
@@ -50,45 +70,39 @@ export function Dailies({
           Today's dailies · {complete}/{total}
         </h2>
         <p className="tnum text-[0.6875rem] text-faint">
-          resets in {formatRemaining(msUntilReset(now, region))}
+          {mixed ? "next reset in " : "resets in "}
+          {formatRemaining(soonest)}
         </p>
       </div>
 
       <ul className="mt-2.5 flex flex-wrap gap-1.5">
-        {games.map((id) => {
-          const game = gameMeta(id);
-          const key = dailiesId(id);
-          return (
-            <li key={key}>
+        {chores.map((chore) => (
+          <li key={chore.key}>
             <TickChip
-                label={game.short}
-                hue={game.hue}
-                title={game.dailyTasks}
-                ariaLabel={`${game.name} dailies — ${game.dailyTasks}`}
-                days={daysFor(key)}
-                today={today}
-                onToggle={() => onToggleDay(key, today)}
+              label={chore.game.short}
+              hue={chore.game.hue}
+              title={chore.game.dailyTasks}
+              ariaLabel={`${chore.game.name} dailies — ${chore.game.dailyTasks}`}
+              days={daysFor(chore.key)}
+              today={chore.today}
+              onToggle={() => onToggleDay(chore.key, chore.today)}
             />
           </li>
-          );
-        })}
+        ))}
 
-        {events.map((event) => {
-          const game = gameMeta(event.game);
-          return (
-            <li key={event.id}>
+        {repeating.map((row) => (
+          <li key={row.key}>
             <TickChip
-                label={event.title}
-                hue={game.hue}
-                title={`${game.name} — ${event.title}`}
-                ariaLabel={`${event.title} (${game.name})`}
-                days={daysFor(event.id)}
-                today={today}
-                onToggle={() => onToggleDay(event.id, today)}
+              label={row.event.title}
+              hue={row.game.hue}
+              title={`${row.game.name} — ${row.event.title}`}
+              ariaLabel={`${row.event.title} (${row.game.name})`}
+              days={daysFor(row.key)}
+              today={row.today}
+              onToggle={() => onToggleDay(row.key, row.today)}
             />
           </li>
-          );
-        })}
+        ))}
       </ul>
 
       <p className="mt-2 text-[0.6875rem] leading-relaxed text-faint">

src/client/components/DailyChecklist.tsx

@@ -3,7 +3,7 @@ import {
   msUntilReset,
   type DailySummary,
 } from "../../shared/daily.ts";
-import type { Region } from "../../shared/schema.ts";
+import type { GameId, Region } from "../../shared/schema.ts";
 import { formatRemaining } from "../../shared/time.ts";
 
 /**
@@ -23,6 +23,7 @@ export function DailyChecklist({
   startsMs,
   endsMs,
   region,
+  game,
   now,
   logged,
   onToggleDay,
@@ -30,11 +31,13 @@ export function DailyChecklist({
   startsMs: number;
   endsMs: number | null;
   region: Region;
+  /** Whose reset clock the days are counted on — not every game shares one. */
+  game: GameId;
   now: number;
   logged: string[];
   onToggleDay: (day: string) => void;
 }) {
-  const summary = dailySummary({ startsMs, endsMs, region, now, logged });
+  const summary = dailySummary({ startsMs, endsMs, region, game, now, logged });
   const { days, today, doneToday, todayInWindow } = summary;
   const started = now >= startsMs;
 
@@ -43,7 +46,7 @@ export function DailyChecklist({
       <div className="flex items-baseline justify-between gap-3">
         <p className="eyebrow">Daily checklist</p>
         <p className="tnum text-[0.6875rem] text-faint">
-          resets in {formatRemaining(msUntilReset(now, region))}
+          resets in {formatRemaining(msUntilReset(now, region, game))}
         </p>
       </div>
 

src/client/components/EventDetail.tsx

@@ -151,6 +151,7 @@ export function EventDetail({
               startsMs={clock.startsMs}
               endsMs={clock.endsMs}
               region={region}
+              game={event.game}
               now={now}
               logged={dailyDays}
               onToggleDay={(day) => onToggleDay(event.id, day)}

src/shared/daily.ts

@@ -1,3 +1,4 @@
+import { GAMES } from "./games.ts";
 import type { GachaEvent, GameId, Region } from "./schema.ts";
 import { DAY, HOUR, REGION_RESET_UTC_OFFSET } from "./time.ts";
 
@@ -113,9 +114,35 @@ export function dailyOverride(
   return desired === detected ? undefined : desired;
 }
 
-/** Offset from UTC midnight to this region's reset instant. */
-function shift(region: Region): number {
-  return REGION_RESET_UTC_OFFSET[region] * HOUR - RESET_HOUR_LOCAL * HOUR;
+/**
+ * The UTC offset of the server clock a reader's day rolls on.
+ *
+ * The reader's region is always the question; a game can just answer it
+ * differently. Most run a server per region and take the default. One that
+ * serves two regions off a single machine lists the regions that differ in
+ * `resetOffsets` — Endfield's European players sit on the Americas server, so
+ * `europe` resolves to UTC-5 there and to UTC+1 everywhere else.
+ *
+ * A blanket per-game offset would be the wrong shape: it would drag the regions
+ * that *do* have their own server onto somebody else's clock, which is a
+ * different bug in the same place.
+ */
+export function serverOffsetUtc(region: Region, game?: GameId): number {
+  const override = game === undefined ? undefined : GAMES[game].resetOffsets?.[region];
+  return override ?? REGION_RESET_UTC_OFFSET[region];
+}
+
+/**
+ * Offset from UTC midnight to this game's reset instant.
+ *
+ * Everything downstream of this is a **localStorage key**. Moving the reset
+ * hour, a region offset, or a game's own override re-labels the game-day some
+ * already-logged ticks fall in — at most by one day, and never by deleting one,
+ * but it is still the reader's streak moving under them. Treat a change here as
+ * a data change, not a constant.
+ */
+function shift(region: Region, game?: GameId): number {
+  return serverOffsetUtc(region, game) * HOUR - RESET_HOUR_LOCAL * HOUR;
 }
 
 /**
@@ -123,20 +150,24 @@ function shift(region: Region): number {
  *
  * These are storage keys, and they are compared with `<` elsewhere in this
  * module, so the format is fixed and sortable on purpose.
+ *
+ * `game` is optional because a caller that has no particular game in hand — a
+ * generic "what day is it here?" — still gets the regional answer. Anything
+ * that reads or writes a tick should pass it.
  */
-export function dayKey(ms: number, region: Region): string {
-  return new Date(ms + shift(region)).toISOString().slice(0, 10);
+export function dayKey(ms: number, region: Region, game?: GameId): string {
+  return new Date(ms + shift(region, game)).toISOString().slice(0, 10);
 }
 
 /** The next reset instant strictly after `ms`. */
-export function nextResetMs(ms: number, region: Region): number {
-  const shifted = ms + shift(region);
-  return Math.floor(shifted / DAY) * DAY + DAY - shift(region);
+export function nextResetMs(ms: number, region: Region, game?: GameId): number {
+  const s = shift(region, game);
+  return Math.floor((ms + s) / DAY) * DAY + DAY - s;
 }
 
 /** How long the reader has left to do today's dailies. */
-export function msUntilReset(ms: number, region: Region): number {
-  return nextResetMs(ms, region) - ms;
+export function msUntilReset(ms: number, region: Region, game?: GameId): number {
+  return nextResetMs(ms, region, game) - ms;
 }
 
 /**
@@ -150,6 +181,7 @@ export function dailyDays(
   startsMs: number,
   endsMs: number | null,
   region: Region,
+  game?: GameId,
 ): string[] | null {
   if (endsMs === null) return null;
 
@@ -158,11 +190,11 @@ export function dailyDays(
   // reset: an event ending at 04:00 gives you nothing on that final day.
   const last = endsMs - 1;
   let cursor = startsMs;
-  if (last < startsMs) return [dayKey(startsMs, region)];
+  if (last < startsMs) return [dayKey(startsMs, region, game)];
 
   while (cursor <= last && out.length < MAX_DAYS) {
-    out.push(dayKey(cursor, region));
-    cursor = nextResetMs(cursor, region);
+    out.push(dayKey(cursor, region, game));
+    cursor = nextResetMs(cursor, region, game);
   }
   return out;
 }
@@ -197,12 +229,14 @@ export function dailySummary(input: {
   startsMs: number;
   endsMs: number | null;
   region: Region;
+  /** Whose reset clock this runs on. Omitted falls back to the region's. */
+  game?: GameId | undefined;
   now: number;
   logged: readonly string[];
 }): DailySummary {
-  const { startsMs, endsMs, region, now, logged } = input;
-  const days = dailyDays(startsMs, endsMs, region);
-  const today = dayKey(now, region);
+  const { startsMs, endsMs, region, game, now, logged } = input;
+  const days = dailyDays(startsMs, endsMs, region, game);
+  const today = dayKey(now, region, game);
   const ticked = new Set(logged);
 
   const inWindow = days === null ? logged.slice() : days.filter((d) => ticked.has(d));
@@ -220,7 +254,7 @@ export function dailySummary(input: {
         ? null
         : days.filter((d) => d < today && !ticked.has(d)).length,
     streak: streakOf(logged, today),
-    msUntilReset: msUntilReset(now, region),
+    msUntilReset: msUntilReset(now, region, game),
   };
 }
 

src/shared/games.ts

@@ -1,4 +1,4 @@
-import type { GameId } from "./schema.ts";
+import type { GameId, Region } from "./schema.ts";
 
 export interface GameMeta {
   id: GameId;
@@ -20,6 +20,24 @@ export interface GameMeta {
    * no hint at all.
    */
   dailyTasks: string;
+  /**
+   * Server clock offsets that differ from the regional default, per region.
+   *
+   * Not every game runs one server per region. Where a game serves two of our
+   * regions off a single machine, the reader's region is still the right
+   * question — it just gets a different answer for that game than
+   * `REGION_RESET_UTC_OFFSET` gives.
+   *
+   * Deliberately a sparse override rather than a full table: listing only the
+   * regions that actually differ keeps the diff to the fact that changed, and
+   * a region absent here keeps the default answer it has always had.
+   *
+   * This feeds `dayKey`, which is a **localStorage key**. Adding or changing an
+   * entry re-labels the game-day some already-logged ticks fall in, for readers
+   * in that region only — see `src/shared/daily.ts` § shift and
+   * docs/DATA-MODEL.md.
+   */
+  resetOffsets?: Partial<Record<Region, number>> | undefined;
 }
 
 export const GAMES: Record<GameId, GameMeta> = {
@@ -28,7 +46,12 @@ export const GAMES: Record<GameId, GameMeta> = {
   zzz: { id: "zzz", name: "Zenless Zone Zero", short: "ZZZ", hue: "#F2A03D" , studio: "HoYoverse", dailyTasks: "Daily missions, battery" },
   wuwa: { id: "wuwa", name: "Wuthering Waves", short: "Wuwa", hue: "#3DD6A0" , studio: "Kuro Games", dailyTasks: "Daily activity, waveplate" },
   arknights: { id: "arknights", name: "Arknights", short: "Arknights", hue: "#9AA3B8" , studio: "Hypergryph", dailyTasks: "Daily missions, sanity" },
-  endfield: { id: "endfield", name: "Arknights: Endfield", short: "Endfield", hue: "#E8635A" , studio: "Hypergryph", dailyTasks: "Daily missions" },
+  // Endfield has two server groups, not three: Europe is served off the same
+  // machine as the Americas, on a fixed UTC-5. So a European player's day rolls
+  // at 09:00 UTC — 11:00 in Copenhagen in summer, 10:00 in winter — six hours
+  // after the HoYo/Kuro pattern above. Asia has its own server and is unchanged,
+  // and `america` already resolves to -5, so Europe is the only real override.
+  endfield: { id: "endfield", name: "Arknights: Endfield", short: "Endfield", hue: "#E8635A" , studio: "Hypergryph", dailyTasks: "Daily missions", resetOffsets: { europe: -5 } },
   nte: { id: "nte", name: "Neverness to Everness", short: "NTE", hue: "#C77DFF" , studio: "Hotta Studio", dailyTasks: "Daily tasks" },
 };
 

test/daily.test.ts

@@ -133,6 +133,86 @@ describe("dayKey", () => {
   });
 });
 
+describe("a game whose server map differs from the default", () => {
+  // Endfield has two server groups, not three: Europe is served off the
+  // Americas machine on a fixed UTC-5, so a European player's 04:00 reset is
+  // 09:00 UTC — six hours after the HoYo/Kuro Europe pattern. Asia has its own
+  // server and is unaffected.
+  const morning = at("2026-08-16T08:00:00Z");
+
+  test("the override beats the regional default for that region", () => {
+    expect(dayKey(morning, "europe", "endfield")).toBe("2026-08-15");
+    expect(dayKey(morning, "europe", "genshin")).toBe("2026-08-16");
+  });
+
+  test("rolls exactly on 09:00 UTC in Europe", () => {
+    expect(dayKey(at("2026-08-16T08:59:59Z"), "europe", "endfield")).toBe(
+      "2026-08-15",
+    );
+    expect(dayKey(at("2026-08-16T09:00:00Z"), "europe", "endfield")).toBe(
+      "2026-08-16",
+    );
+    expect(nextResetMs(morning, "europe", "endfield")).toBe(
+      at("2026-08-16T09:00:00Z"),
+    );
+  });
+
+  test("a region with its own server keeps the answer it always had", () => {
+    // The override is per region on purpose. A blanket per-game offset would
+    // drag Asia — which genuinely has its own Endfield server — onto the
+    // Americas clock, moving a reader's already-logged day keys by eleven
+    // hours to fix a bug they never had.
+    for (const region of ["asia", "america"] as const) {
+      for (const hour of [0, 6, 9, 14, 20, 23]) {
+        const t = at(`2026-08-16T${String(hour).padStart(2, "0")}:30:00Z`);
+        expect(dayKey(t, region, "endfield")).toBe(dayKey(t, region));
+      }
+    }
+  });
+
+  test("a game with no override still follows its region", () => {
+    // Europe is UTC+1, so 03:00 UTC. Asia rolled six hours before that.
+    const instant = at("2026-08-16T02:00:00Z");
+    expect(dayKey(instant, "europe", "genshin")).toBe("2026-08-15");
+    expect(dayKey(instant, "asia", "genshin")).toBe("2026-08-16");
+    // …and matches the answer given with no game at all.
+    expect(dayKey(instant, "europe", "genshin")).toBe(dayKey(instant, "europe"));
+  });
+
+  test("the checklist counts days on the clock that reader is actually on", () => {
+    const start = at("2026-08-16T09:00:00Z"); // an endfield europe reset
+    expect(dailyDays(start, start + 3 * DAY, "europe", "endfield")).toEqual([
+      "2026-08-16",
+      "2026-08-17",
+      "2026-08-18",
+    ]);
+
+    const summary = dailySummary({
+      startsMs: start,
+      endsMs: start + 3 * DAY,
+      region: "europe",
+      game: "endfield",
+      now: at("2026-08-17T08:00:00Z"), // still the 16th on a UTC-5 server
+      logged: [],
+    });
+    expect(summary.today).toBe("2026-08-16");
+    expect(summary.msUntilReset).toBe(HOUR);
+  });
+
+  test("an Asia reader's checklist is byte-identical to before the override", () => {
+    // The regression this guards: an Endfield event whose end lands between the
+    // two candidate resets loses its final claimable day if the wrong clock is
+    // used, and a day that leaves `dailyDays` can never be ticked or untucked
+    // again — the pip is simply not rendered.
+    const start = at("2026-08-06T04:00:00Z");
+    const end = at("2026-08-19T22:00:00Z");
+    expect(dailyDays(start, end, "asia", "endfield")).toEqual(
+      dailyDays(start, end, "asia"),
+    );
+    expect(dailyDays(start, end, "asia", "endfield")).toContain("2026-08-20");
+  });
+});
+
 describe("nextResetMs", () => {
   test("is the next reset strictly after the instant given", () => {
     const reset = at("2026-08-15T20:00:00Z"); // asia