feat(games): track Reverse: 1999, which resets at 05:00

Adds the r1999 GameId and its metadata, plus GameMeta.resetHourLocal for
the fact that makes it unlike every other game here: it rolls its day at
05:00 server time rather than 04:00, on a single global UTC-5 server, so
its day-key boundary is 10:00 UTC.

resetOffsets could not carry that. Landing 10:00 UTC through the offset
would mean claiming a UTC-6 server, and serverOffsetUtc answers more
questions than this one. The new field overrides RESET_HOUR_LOCAL per game
and is absent everywhere else, so no existing reader's logged day moved —
a test pins that for the games that already had readers.

Both facts are read off the source, not assumed: all 154 rows of the
wiki's event list state (UTC-5) and run 05:00 to 04:59, an event ending
one minute before the reset the next one begins on.

No adapter yet, so the game has no events until one lands.

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

AGENTS.md

@@ -170,7 +170,12 @@ Two more key spaces have the same property, for the same reason:
   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
+  regions that do have their own server onto someone else's clock.
+  A game that rolls on a different *hour* says so in `resetHourLocal` instead — Reverse: 1999 resets
+  at 05:00, not 04:00, so its day rolls at 10:00 UTC on its single UTC-5 server. Do not encode that
+  as a bent `resetOffsets` value: shifting a game's stated server offset to land the right instant
+  would misreport the server clock to everything else that asks for it. Both fields are absent for
+  every game that takes the default, which is why adding the second one moved nobody's day keys. 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.

docs/DATA-MODEL.md

@@ -9,7 +9,7 @@
 import { z } from "zod";
 
 export const GameId = z.enum([
-  "genshin", "hsr", "zzz", "wuwa", "arknights", "endfield", "nte", "nikki", "p5x",
+  "genshin", "hsr", "zzz", "wuwa", "arknights", "endfield", "nte", "nikki", "p5x", "r1999",
 ]);
 
 export const EventType = z.enum([
@@ -258,6 +258,7 @@ reader cannot see.
 | Arknights, all regions | 04:00 | UTC-7 (one Global server) | 11:00 | 13:00 / 12:00 |
 | 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 | — |
+| Reverse: 1999, all regions | **05:00** | UTC-5 (one global server) | 10:00 | 12:00 / 11:00 |
 
 Arknights is the one game whose override covers **all three** regions, and it is not a blanket
 per-game offset of the kind this section warns about below: the game genuinely runs a single Global
@@ -270,6 +271,15 @@ an assumption, not a verified server map — neither source states one. Confirm
 before relying on it, and note that adding an override later re-labels the game-day of ticks readers
 have already logged, which is the change this table warns about below.
 
+**Reverse: 1999 is the one game that rolls on a different hour**, and it needs its own field rather
+than a bent offset. It runs a single global server on UTC-5 and resets at **05:00**, so its day rolls
+at 10:00 UTC. `resetOffsets` alone cannot say that: landing 10:00 UTC through the offset would mean
+claiming a UTC-6 server, which is a lie every other reader of `serverOffsetUtc` would inherit. So
+`GameMeta.resetHourLocal` overrides `RESET_HOUR_LOCAL` per game, and is absent — meaning 04:00 — for
+everything else, which is why introducing it moved no existing day key. Both facts come off the
+source: all 154 rows of the wiki's event list state `(UTC-5)`, and every one runs 05:00 → 04:59, an
+event ending one minute before the reset the next one starts on.
+
 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.
 

src/shared/daily.ts

@@ -137,6 +137,24 @@ export function serverOffsetUtc(region: Region, game?: LaneId): number {
   return override ?? REGION_RESET_UTC_OFFSET[region];
 }
 
+/**
+ * The hour of its own server day a game rolls over on.
+ *
+ * Almost always `RESET_HOUR_LOCAL`. A game that resets on a different hour says
+ * so in `resetHourLocal` (`games.ts`) — Reverse: 1999 rolls at 05:00 — and that
+ * cannot be folded into `serverOffsetUtc`: shifting a game's stated offset to
+ * land the right reset instant would misreport the server clock to everything
+ * else that asks for it.
+ *
+ * A lane the reader invented has no server to know about and takes the default,
+ * for the same reason `serverOffsetUtc` does.
+ */
+export function resetHourFor(game?: LaneId): number {
+  const override =
+    game === undefined ? undefined : GAMES[game as GameId]?.resetHourLocal;
+  return override ?? RESET_HOUR_LOCAL;
+}
+
 /**
  * Offset from UTC midnight to this game's reset instant.
  *
@@ -147,7 +165,7 @@ export function serverOffsetUtc(region: Region, game?: LaneId): number {
  * a data change, not a constant.
  */
 function shift(region: Region, game?: LaneId): number {
-  return serverOffsetUtc(region, game) * HOUR - RESET_HOUR_LOCAL * HOUR;
+  return serverOffsetUtc(region, game) * HOUR - resetHourFor(game) * HOUR;
 }
 
 /**

src/shared/games.ts

@@ -39,6 +39,21 @@ export interface GameMeta {
    * docs/DATA-MODEL.md.
    */
   resetOffsets?: Partial<Record<Region, number>> | undefined;
+  /**
+   * The hour of the server's own day this game rolls over on, when it is not
+   * `RESET_HOUR_LOCAL` (04:00).
+   *
+   * Most gacha servers reset at 04:00 local. Reverse: 1999 resets at 05:00, and
+   * the difference is not cosmetic: `resetOffsets` alone cannot express it,
+   * because bending a game's stated server offset to land the right instant
+   * would put every other reader of that offset an hour out.
+   *
+   * Like `resetOffsets` this feeds `dayKey`, which is a **localStorage key**, so
+   * the same warning applies — changing it for a game that already has readers
+   * re-labels the game-day their logged ticks fall in. Absent means 04:00, which
+   * is why adding this field moved no existing game.
+   */
+  resetHourLocal?: number | undefined;
 }
 
 export const GAMES: Record<GameId, GameMeta> = {
@@ -66,6 +81,12 @@ export const GAMES: Record<GameId, GameMeta> = {
   // from the regional default, and an offset invented here would move real
   // readers' day keys. Add one only against evidence — see games.ts § resetOffsets.
   p5x: { id: "p5x", name: "Persona 5: The Phantom X", short: "P5X", hue: "#D62246" , studio: "Perfect World", dailyTasks: "Daily missions, stamina" },
+  // Reverse: 1999 runs one global server on a fixed UTC-5 and rolls its day at
+  // **05:00**, not the 04:00 every other game here uses. Both facts come from
+  // the source rather than from habit: all 154 rows on the wiki's event list
+  // state `(UTC-5)`, and every one of them starts at 05:00 and ends at 04:59 —
+  // an event ending one minute before the reset that the next one begins on.
+  r1999: { id: "r1999", name: "Reverse: 1999", short: "R1999", hue: "#C9A227" , studio: "Bluepoch", dailyTasks: "Daily missions", resetOffsets: { asia: -5, america: -5, europe: -5 }, resetHourLocal: 5 },
 };
 
 export const GAME_LIST: GameMeta[] = Object.values(GAMES);

src/shared/schema.ts

@@ -10,6 +10,7 @@ export const GameId = z.enum([
   "nte", // Neverness to Everness
   "nikki", // Infinity Nikki
   "p5x", // Persona 5: The Phantom X
+  "r1999", // Reverse: 1999
 ]);
 export type GameId = z.infer<typeof GameId>;
 

test/daily.test.ts

@@ -8,6 +8,8 @@ import {
   isDaily,
   msUntilReset,
   nextResetMs,
+  resetHourFor,
+  RESET_HOUR_LOCAL,
   resolveDaily,
   streakOf,
 } from "../src/shared/daily.ts";
@@ -358,3 +360,48 @@ describe("dailiesId", () => {
     expect(dailiesId("genshin").split(":")).toHaveLength(2);
   });
 });
+
+describe("a game whose day rolls on a different hour", () => {
+  // Reverse: 1999 runs one global server on UTC-5 and resets at 05:00 rather
+  // than 04:00, so its day rolls at 10:00 UTC. Both facts are read off the
+  // source: every row of its event list states (UTC-5) and runs 05:00 → 04:59.
+  test("rolls on 10:00 UTC, not the 09:00 a UTC-5 game would", () => {
+    expect(dayKey(at("2026-08-16T09:59:59Z"), "europe", "r1999")).toBe(
+      "2026-08-15",
+    );
+    expect(dayKey(at("2026-08-16T10:00:00Z"), "europe", "r1999")).toBe(
+      "2026-08-16",
+    );
+    expect(nextResetMs(at("2026-08-16T08:00:00Z"), "europe", "r1999")).toBe(
+      at("2026-08-16T10:00:00Z"),
+    );
+  });
+
+  test("every region gets the same answer, because there is one server", () => {
+    const instant = at("2026-08-16T09:30:00Z");
+    const keys = (["asia", "america", "europe"] as const).map((r) =>
+      dayKey(instant, r, "r1999"),
+    );
+    expect(new Set(keys).size).toBe(1);
+  });
+
+  test("resetHourFor defaults to 04:00 for every other game", () => {
+    // Adding the field must not have moved a single existing reader's day key,
+    // which is why it is an override rather than a per-game table.
+    expect(resetHourFor("r1999")).toBe(5);
+    for (const game of ["genshin", "endfield", "arknights", undefined] as const) {
+      expect(resetHourFor(game)).toBe(RESET_HOUR_LOCAL);
+    }
+    // A lane the reader invented has no server map and takes the default too.
+    expect(resetHourFor("mygame:my-own-game")).toBe(RESET_HOUR_LOCAL);
+  });
+
+  test("an event's checklist counts days on the 05:00 clock", () => {
+    const start = at("2026-08-13T10:00:00Z"); // an r1999 reset
+    expect(dailyDays(start, start + 3 * DAY, "europe", "r1999")).toEqual([
+      "2026-08-13",
+      "2026-08-14",
+      "2026-08-15",
+    ]);
+  });
+});