feat(missions): schedule Friday side ops in the unit timezone

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/app/(frontend)/intelligence/missions/actions.ts

@@ -10,6 +10,14 @@ import { isPayloadUser } from "@/utils/access-control/isPayloadUser";
 import { emitGameEvent } from "@/utils/event-log/emit";
 import { EventTypes } from "@/utils/event-log/eventTypes";
 import { textToLexical } from "@/lib/intelligence/briefingText";
+import {
+  nextDayKey,
+  parseDateKey,
+  wallTimeToInstant,
+  zonedDateKey,
+  zonedParts,
+  zonedWeekday,
+} from "@/lib/intelligence/fridayTime";
 import type { Mission } from "@/payload-types";
 
 export interface ActionResult<T = undefined> {
@@ -74,14 +82,18 @@ function isFridayDate(value: string): boolean {
   if (Number.isNaN(date.getTime())) {
     return false;
   }
-  return date.getDay() === 5;
+  return zonedWeekday(date) === 5;
 }
 
-// Side ops always start 20:00 server-local (Eastern) on the validated Friday.
+// Side ops always start 20:00 America/New_York on the validated Friday,
+// regardless of the server's own timezone (prod runs UTC).
 function fridayStartDateTime(value: string): string {
   const date = new Date(value);
-  date.setHours(20, 0, 0, 0);
-  return date.toISOString();
+  if (Number.isNaN(date.getTime())) {
+    return date.toISOString();
+  }
+  const p = zonedParts(date);
+  return wallTimeToInstant(p.year, p.month, p.day, 20, 0).toISOString();
 }
 
 type SideOpMissionUser = {
@@ -317,10 +329,11 @@ async function findActiveMissionOnFriday(
   excludeMissionId?: number,
 ): Promise<{ id: number; name: string; codeName: string } | null> {
   const start = new Date(fridayStartDateTime(startDateTime));
-  const dayStart = new Date(start);
-  dayStart.setHours(0, 0, 0, 0);
-  const dayEnd = new Date(dayStart);
-  dayEnd.setDate(dayEnd.getDate() + 1);
+  const key = zonedDateKey(start);
+  const { year, month, day } = parseDateKey(key);
+  const next = parseDateKey(nextDayKey(key));
+  const dayStart = wallTimeToInstant(year, month, day);
+  const dayEnd = wallTimeToInstant(next.year, next.month, next.day);
 
   const res = await payload.find({
     collection: "missions",

src/app/(frontend)/intelligence/missions/calendar/page.tsx

@@ -7,6 +7,13 @@ import {
   type FridayCalendarMission,
 } from "@/components/frontend/intelligence/FridayCalendar";
 import type { SideOpDialogOption } from "@/components/frontend/intelligence/CreateSideOpDialog";
+import {
+  dateKeyOf,
+  nextDayKey,
+  parseDateKey,
+  wallTimeToInstant,
+  zonedDateKey,
+} from "@/lib/intelligence/fridayTime";
 
 export const metadata = {
   title: "Friday Operations",
@@ -16,15 +23,16 @@ const MAX_SCHEDULED_AHEAD_MISSIONS = 2;
 
 const FRIDAYS_SHOWN = 8;
 
-function nextFridays(count: number): Date[] {
-  const fridays: Date[] = [];
-  const cursor = new Date();
-  cursor.setHours(0, 0, 0, 0);
+function nextFridays(count: number): string[] {
+  const fridays: string[] = [];
+  const cursor = zonedDateKey(new Date());
+  const [y, m, d] = cursor.split("-").map(Number);
+  const utc = new Date(Date.UTC(y, m - 1, d));
   while (fridays.length < count) {
-    if (cursor.getDay() === 5) {
-      fridays.push(new Date(cursor));
+    if (utc.getUTCDay() === 5) {
+      fridays.push(dateKeyOf(utc.getUTCFullYear(), utc.getUTCMonth() + 1, utc.getUTCDate()));
     }
-    cursor.setDate(cursor.getDate() + 1);
+    utc.setUTCDate(utc.getUTCDate() + 1);
   }
   return fridays;
 }
@@ -38,9 +46,10 @@ export default async function FridayCalendarPage() {
   });
 
   const fridays = nextFridays(FRIDAYS_SHOWN);
-  const rangeStart = fridays[0];
-  const rangeEnd = new Date(fridays[fridays.length - 1]);
-  rangeEnd.setDate(rangeEnd.getDate() + 1);
+  const first = parseDateKey(fridays[0]);
+  const last = parseDateKey(nextDayKey(fridays[fridays.length - 1]));
+  const rangeStart = wallTimeToInstant(first.year, first.month, first.day);
+  const rangeEnd = wallTimeToInstant(last.year, last.month, last.day);
 
   const missionsRes = await payload.find({
     collection: "missions",
@@ -63,15 +72,9 @@ export default async function FridayCalendarPage() {
     },
   });
 
-  const entries: FridayCalendarEntry[] = fridays.map((friday) => {
-    const dayStart = new Date(friday);
-    const dayEnd = new Date(friday);
-    dayEnd.setDate(dayEnd.getDate() + 1);
+  const entries: FridayCalendarEntry[] = fridays.map((fridayKey) => {
     const missions: FridayCalendarMission[] = missionsRes.docs
-      .filter((m) => {
-        const start = new Date(m.classification.startDateTime);
-        return start >= dayStart && start < dayEnd;
-      })
+      .filter((m) => zonedDateKey(new Date(m.classification.startDateTime)) === fridayKey)
       .map((m) => {
         const map = m.classification.map;
         const createdBy = m.createdBy;
@@ -88,7 +91,12 @@ export default async function FridayCalendarPage() {
             (typeof createdBy === "object" ? createdBy?.id : createdBy) === user.id,
         };
       });
-    return { fridayIso: friday.toISOString(), missions };
+    const k = parseDateKey(fridayKey);
+    return {
+      fridayIso: fridayKey,
+      startIso: wallTimeToInstant(k.year, k.month, k.day, 20, 0).toISOString(),
+      missions,
+    };
   });
 
   let remainingSlots = 0;

src/components/frontend/intelligence/FridayCalendar.tsx

@@ -7,6 +7,7 @@ import { CalendarDaysIcon, ChevronRightIcon, PlusIcon } from "lucide-react";
 import { Item, ItemContent, ItemHeader, ItemTitle } from "@/components/ui/item";
 import { Button } from "@/components/ui/button";
 import { CreateSideOpDialog, type SideOpDialogOption } from "./CreateSideOpDialog";
+import { parseDateKey } from "@/lib/intelligence/fridayTime";
 
 export interface FridayCalendarMission {
   id: number;
@@ -21,6 +22,7 @@ export interface FridayCalendarMission {
 
 export interface FridayCalendarEntry {
   fridayIso: string;
+  startIso: string;
   missions: FridayCalendarMission[];
 }
 
@@ -44,7 +46,8 @@ const statusColors: Record<string, string> = {
 };
 
 function formatFriday(iso: string): string {
-  return new Date(iso).toLocaleDateString(undefined, {
+  const { year, month, day } = parseDateKey(iso);
+  return new Date(year, month - 1, day).toLocaleDateString(undefined, {
     weekday: "long",
     month: "long",
     day: "numeric",
@@ -58,12 +61,6 @@ function formatTime(iso: string): string {
   });
 }
 
-function defaultStartForFriday(fridayIso: string): string {
-  const date = new Date(fridayIso);
-  date.setHours(20, 0, 0, 0);
-  return date.toISOString();
-}
-
 export function FridayCalendar({
   entries,
   remainingSlots,
@@ -119,7 +116,7 @@ export function FridayCalendar({
                   size="sm"
                   variant="outline"
                   disabled={!canSchedule}
-                  onClick={() => setScheduleFor(entry.fridayIso)}
+                  onClick={() => setScheduleFor(entry.startIso)}
                 >
                   <PlusIcon className="size-3.5" />
                   {fridayTaken ? "Taken" : "Schedule"}
@@ -182,7 +179,7 @@ export function FridayCalendar({
         maps={maps}
         campaigns={campaigns}
         modLists={modLists}
-        defaultStartDateTime={scheduleFor ? defaultStartForFriday(scheduleFor) : undefined}
+        defaultStartDateTime={scheduleFor ?? undefined}
         onSaved={() => router.refresh()}
       />
     </div>

src/lib/intelligence/fridayTime.ts

@@ -0,0 +1,81 @@
+export const UNIT_TIME_ZONE = "America/New_York";
+
+export interface ZonedParts {
+  year: number;
+  month: number;
+  day: number;
+  hour: number;
+  minute: number;
+  second: number;
+}
+
+export function zonedParts(date: Date, timeZone: string = UNIT_TIME_ZONE): ZonedParts {
+  const parts = new Intl.DateTimeFormat("en-US", {
+    timeZone,
+    hour12: false,
+    year: "numeric",
+    month: "2-digit",
+    day: "2-digit",
+    hour: "2-digit",
+    minute: "2-digit",
+    second: "2-digit",
+  }).formatToParts(date);
+  const get = (type: string) => Number(parts.find((p) => p.type === type)?.value ?? 0);
+  return {
+    year: get("year"),
+    month: get("month"),
+    day: get("day"),
+    hour: get("hour") % 24,
+    minute: get("minute"),
+    second: get("second"),
+  };
+}
+
+function pad2(n: number): string {
+  return String(n).padStart(2, "0");
+}
+
+export function dateKeyOf(year: number, month: number, day: number): string {
+  return `${String(year).padStart(4, "0")}-${pad2(month)}-${pad2(day)}`;
+}
+
+export function zonedDateKey(date: Date, timeZone: string = UNIT_TIME_ZONE): string {
+  const p = zonedParts(date, timeZone);
+  return dateKeyOf(p.year, p.month, p.day);
+}
+
+function tzOffsetMs(date: Date, timeZone: string): number {
+  const p = zonedParts(date, timeZone);
+  const asUtc = Date.UTC(p.year, p.month - 1, p.day, p.hour, p.minute, p.second);
+  return asUtc - date.getTime();
+}
+
+export function wallTimeToInstant(
+  year: number,
+  month: number,
+  day: number,
+  hour = 0,
+  minute = 0,
+  timeZone: string = UNIT_TIME_ZONE,
+): Date {
+  const guess = Date.UTC(year, month - 1, day, hour, minute);
+  let ts = guess - tzOffsetMs(new Date(guess), timeZone);
+  ts = guess - tzOffsetMs(new Date(ts), timeZone);
+  return new Date(ts);
+}
+
+export function nextDayKey(key: string): string {
+  const [y, m, d] = key.split("-").map(Number);
+  const next = new Date(Date.UTC(y, m - 1, d + 1));
+  return dateKeyOf(next.getUTCFullYear(), next.getUTCMonth() + 1, next.getUTCDate());
+}
+
+export function zonedWeekday(date: Date, timeZone: string = UNIT_TIME_ZONE): number {
+  const p = zonedParts(date, timeZone);
+  return new Date(Date.UTC(p.year, p.month - 1, p.day)).getUTCDay();
+}
+
+export function parseDateKey(key: string): { year: number; month: number; day: number } {
+  const [y, m, d] = key.split("-").map(Number);
+  return { year: y, month: m, day: d };
+}