fix: measure the SGA Spaces buffer in the timezone it is stored in (#87)

app/api/display/[spaceId]/route.ts

@@ -1,5 +1,6 @@
 import { createClient as createAdminClient } from '@supabase/supabase-js'
 import { NextResponse } from 'next/server'
+import { bostonWallClockNow } from '@/lib/boston-time'
 
 const adminSupabase = createAdminClient(
   process.env.NEXT_PUBLIC_SUPABASE_URL!,
@@ -21,10 +22,17 @@ export async function GET(
 
   // Use the client-supplied local date (YYYY-MM-DD) so "today" matches the
   // display's clock rather than the server's UTC clock.
+  //
+  // The fallback is Boston wall clock, not the server's UTC date. Bookings are
+  // stored as wall-clock digits labelled Z, so a UTC "today" is already tomorrow
+  // after 8 PM EDT and the kiosk would ask for the wrong day's bookings. The
+  // display page always sends the parameter, so this is unreachable from it --
+  // but it is the same trap as issue #87 and worth not leaving armed for the
+  // next caller.
   const dateParam = searchParams.get('date')
   const [year, month, day] = dateParam
     ? dateParam.split('-').map(Number)
-    : (() => { const n = new Date(); return [n.getUTCFullYear(), n.getUTCMonth() + 1, n.getUTCDate()] })()
+    : (() => { const n = bostonWallClockNow(); return [n.getUTCFullYear(), n.getUTCMonth() + 1, n.getUTCDate()] })()
   const todayStart = new Date(Date.UTC(year, month - 1, day))
   const todayEnd = new Date(Date.UTC(year, month - 1, day + 1))
 

app/api/spaces/bookings/[id]/route.ts

@@ -1,6 +1,7 @@
 import { createClient } from '@/lib/supabase/server'
 import { createClient as createAdminClient } from '@supabase/supabase-js'
 import { NextResponse } from 'next/server'
+import { bostonWallClockNow } from '@/lib/boston-time'
 import { checkRateLimit } from '@/lib/check-rate-limit'
 import { sendSpaceBookingCancelledEmail } from '@/lib/emails/space-booking-cancelled'
 import { getAuthedUserWithLiveRoles } from '@/lib/authorization'
@@ -105,7 +106,9 @@ export async function PATCH(request: Request, { params }: { params: Promise<{ id
   const minHours: number = settings?.min_hours_advance_spaces ?? 24
   const startTimeChanged = start_time !== existing.start_time
   if (minHours > 0 && startTimeChanged) {
-    const earliestAllowed = new Date(Date.now() + minHours * 60 * 60 * 1000)
+    // Boston wall-clock now, for the reason given in the POST route: start_time
+    // is wall-clock digits labelled Z, and Date.now() is a real instant.
+    const earliestAllowed = new Date(bostonWallClockNow().getTime() + minHours * 60 * 60 * 1000)
     if (new Date(start_time) < earliestAllowed) {
       return NextResponse.json({
         error: `Bookings must be made at least ${minHours} hour${minHours === 1 ? '' : 's'} in advance.`,

app/api/spaces/bookings/route.ts

@@ -1,6 +1,7 @@
 import { createClient } from '@/lib/supabase/server'
 import { createClient as createAdminClient } from '@supabase/supabase-js'
 import { NextResponse } from 'next/server'
+import { bostonWallClockNow } from '@/lib/boston-time'
 import { checkRateLimit } from '@/lib/check-rate-limit'
 import { sendSpaceBookingConfirmedEmail } from '@/lib/emails/space-booking-confirmed'
 import { getAuthedUserWithLiveRoles } from '@/lib/authorization'
@@ -159,8 +160,13 @@ export async function POST(request: Request) {
   ])
 
   // Advance notice check (skipped when limit is 0)
+  //
+  // Measured from Boston wall-clock now, not Date.now(): start_time carries
+  // wall-clock digits with a Z on the end, so comparing it against a real
+  // instant made every booking look an offset earlier than it was, and the
+  // requirement reject bookings that were comfortably far enough out (issue #87).
   const minHours: number = settings?.min_hours_advance_spaces ?? 24
-  const earliestAllowed = new Date(Date.now() + minHours * 60 * 60 * 1000)
+  const earliestAllowed = new Date(bostonWallClockNow().getTime() + minHours * 60 * 60 * 1000)
   if (minHours > 0 && new Date(start_time) < earliestAllowed) {
     return NextResponse.json({
       error: `Bookings must be made at least ${minHours} hour${minHours === 1 ? '' : 's'} in advance.`,

app/api/spaces/remaining-hours/route.ts

@@ -1,6 +1,7 @@
 import { createClient } from '@/lib/supabase/server'
 import { createClient as createAdminClient } from '@supabase/supabase-js'
 import { NextResponse } from 'next/server'
+import { bostonWallClockNow } from '@/lib/boston-time'
 import { getAuthedUser } from '@/lib/auth'
 
 const adminSupabase = createAdminClient(
@@ -10,8 +11,16 @@ const adminSupabase = createAdminClient(
 
 const DEFAULT_WEEKLY_HOURS = 18
 
+/**
+ * The Sun-Sat window to count this user's hours against.
+ *
+ * Boston wall-clock now, matching the domain space_bookings are stored in. Real
+ * UTC put the boundary in the wrong place for the last four hours of a Saturday
+ * -- UTC is already Sunday by 8 PM EDT, so bookings were counted against next
+ * week and the remaining-hours figure jumped. Same root cause as issue #87.
+ */
 function getWeekBounds(): { weekStart: string; weekEnd: string } {
-  const now = new Date()
+  const now = bostonWallClockNow()
   const day = now.getUTCDay()
   const sun = new Date(now)
   sun.setUTCDate(now.getUTCDate() - day)

lib/boston-time.ts

@@ -0,0 +1,52 @@
+/**
+ * "Now", in the domain SGA Spaces actually stores times in.
+ *
+ * That domain is unusual enough to be worth stating plainly, because nothing
+ * names it: a space booking's start_time holds Boston wall-clock digits with a
+ * Z on the end. A 6 PM booking is stored as T18:00:00.000Z whatever the offset
+ * happens to be that month. The calendar builds slots that way (slotToIso sets
+ * UTC hours straight from the slot index), the modal parses them back with
+ * getUTCHours, and the confirmation email relies on it too -- see the note in
+ * lib/emails/space-booking-confirmed.ts about UTC fields giving the right
+ * local-time digits to pair with TZID=America/New_York.
+ *
+ * It is self-consistent as long as nothing compares those values against a real
+ * instant. Two places did. The advance-notice check measured start_time against
+ * Date.now(), so during EDT every booking looked four hours earlier than it was
+ * and a two-hour requirement rejected anything less than six real hours out
+ * (issue #87). remaining-hours derived its Sun-Sat window from real UTC, so
+ * between 8 PM and midnight on a Saturday it counted against next week.
+ *
+ * Pinned to America/New_York rather than the server's clock: Vercel runs in UTC,
+ * so reading local fields there would be the same bug with an extra step. The
+ * offset is resolved by Intl for the given instant, so EDT and EST are both
+ * handled without a table.
+ */
+export function bostonWallClockNow(at: Date = new Date()): Date {
+  const parts = new Intl.DateTimeFormat('en-US', {
+    timeZone: 'America/New_York',
+    year: 'numeric',
+    month: '2-digit',
+    day: '2-digit',
+    hour: '2-digit',
+    minute: '2-digit',
+    second: '2-digit',
+    hour12: false,
+  }).formatToParts(at)
+
+  const value = (type: Intl.DateTimeFormatPartTypes): number => {
+    const part = parts.find(p => p.type === type)
+    return part ? Number(part.value) : 0
+  }
+
+  return new Date(Date.UTC(
+    value('year'),
+    value('month') - 1,
+    value('day'),
+    // hour12:false yields 24 for midnight in some ICU versions rather than 0,
+    // which would roll the date forward a day.
+    value('hour') % 24,
+    value('minute'),
+    value('second'),
+  ))
+}