fix: group reset history by UTC date

Author: itvincent-git

src/components/codex-reset-history.test.tsx

@@ -121,4 +121,20 @@ describe("CodexResetHistoryModal", () => {
     expect(summary.longestIntervalDays).toBe(4);
     expect(summary.calendarDays.find((day) => day.date.format("YYYY-MM-DD") === "2026-08-24")?.resetType).toBe("mixed");
   });
+
+  it("groups reset announcements by their UTC date", () => {
+    const summary = buildResetHistorySummary([
+      {
+        id: "1",
+        resetType: "banked",
+        announcedAt: "2026-08-21T23:40:12.000Z",
+        text: "A banked reset is available.",
+        source: { author: "source", url: "https://example.com/1" },
+      },
+    ], dayjs("2026-08-26T07:00:00.000+08:00"));
+
+    expect(summary.calendarDays.find((day) => day.date.format("YYYY-MM-DD") === "2026-08-21")?.resetType).toBe("banked");
+    expect(summary.calendarDays.find((day) => day.date.format("YYYY-MM-DD") === "2026-08-22")?.resetType).toBeNull();
+    expect([...summary.calendarDays].reverse().find((day) => day.inRange)?.date.format("YYYY-MM-DD")).toBe("2026-08-25");
+  });
 });

src/components/codex-reset-history.tsx

@@ -1,4 +1,5 @@
 import dayjs, { type Dayjs } from "dayjs";
+import utc from "dayjs/plugin/utc";
 import { ChevronDown, ChevronUp, ExternalLink, RotateCcw, X } from "lucide-react";
 import { useEffect, useMemo, useRef, useState } from "react";
 import { useTranslation } from "react-i18next";
@@ -7,6 +8,8 @@ import { fetchCodexResetHistory, openUrl, type CodexResetAnnouncement } from "@/
 const HISTORY_DAYS = 30;
 const DEFAULT_VISIBLE_RESETS = 5;
 
+dayjs.extend(utc);
+
 type CalendarDay = {
   date: Dayjs;
   inRange: boolean;
@@ -31,12 +34,13 @@ export function buildResetHistorySummary(
   const intervals = sortedResets.slice(0, -1).map((reset, index) =>
     dayjs(reset.announcedAt).diff(sortedResets[index + 1].announcedAt, "minute", true) / (60 * 24),
   );
-  const startDate = now.startOf("day").subtract(HISTORY_DAYS - 1, "day");
-  const endDate = now.endOf("day");
+  const currentDate = now.utc();
+  const startDate = currentDate.startOf("day").subtract(HISTORY_DAYS - 1, "day");
+  const endDate = currentDate.endOf("day");
   const resetsByDate = new Map<string, CodexResetAnnouncement[]>();
 
   for (const reset of sortedResets) {
-    const key = dayjs(reset.announcedAt).format("YYYY-MM-DD");
+    const key = dayjs.utc(reset.announcedAt).format("YYYY-MM-DD");
     const existing = resetsByDate.get(key);
     if (existing) existing.push(reset);
     else resetsByDate.set(key, [reset]);