Count freebuff premium sessions by Pacific day (#598)

jahooma · web-flow · commit 2ac2b09ca506 · 2026-05-05T16:11:23.000-07:00
diff --git a/cli/src/components/waiting-room-screen.tsx b/cli/src/components/waiting-room-screen.tsx
@@ -455,7 +455,7 @@ export const WaitingRoomScreen: React.FC<WaitingRoomScreenProps> = ({
 
           {/* Shared premium-session quota exhausted. Terminal for this run —
               the user can exit and come
-              back once the oldest session in the window rolls off. */}
+              back once the daily Pacific reset passes. */}
           {session?.status === 'rate_limited' && (
             <>
               <text style={{ fg: theme.secondary, marginBottom: 1 }}>
@@ -466,7 +466,7 @@ export const WaitingRoomScreen: React.FC<WaitingRoomScreenProps> = ({
                 <span fg={theme.foreground}>
                   {formatSessionUnits(session.recentCount)} of {session.limit}
                 </span>{' '}
-                premium sessions in the last 20 hours. Try again in{' '}
+                premium sessions today. Try again in{' '}
                 <span fg={theme.foreground}>
                   {formatRetryAfter(session.retryAfterMs)}
                 </span>
diff --git a/common/src/constants/freebuff-models.ts b/common/src/constants/freebuff-models.ts
@@ -1,3 +1,10 @@
+import {
+  addDaysToYmd,
+  getUtcForZonedTime,
+  getZonedParts,
+  type ZonedDateParts,
+} from '../util/zoned-time'
+
 /**
  * Models a freebuff user can pick between in the waiting-room model selector.
  *
@@ -31,18 +38,14 @@ export const FREEBUFF_GLM_MODEL_ID = 'z-ai/glm-5.1'
 export const FREEBUFF_KIMI_MODEL_ID = 'moonshotai/kimi-k2.6'
 export const FREEBUFF_MINIMAX_MODEL_ID = 'minimax/minimax-m2.7'
 export const FREEBUFF_PREMIUM_SESSION_LIMIT = 5
-export const FREEBUFF_PREMIUM_SESSION_WINDOW_HOURS = 20
+export const FREEBUFF_PREMIUM_SESSION_RESET_TIMEZONE = 'America/Los_Angeles'
+export const FREEBUFF_PREMIUM_SESSION_PERIOD = 'pacific_day'
+/** Deprecated wire compatibility field. Premium usage now resets at midnight
+ *  Pacific time rather than using a rolling hourly window. */
+export const FREEBUFF_PREMIUM_SESSION_WINDOW_HOURS = 24
 const FREEBUFF_EASTERN_TIMEZONE = 'America/New_York'
 const FREEBUFF_PACIFIC_TIMEZONE = 'America/Los_Angeles'
 
-interface ZonedDateParts {
-  year: number
-  month: number
-  day: number
-  hour: number
-  minute: number
-}
-
 interface LocalTimeFormatOptions {
   locale?: string
   timeZone?: string
@@ -165,79 +168,6 @@ export function getFreebuffModel(id: string): FreebuffModelOption {
   )
 }
 
-function getZonedParts(date: Date, timeZone: string): ZonedDateParts {
-  const parts = new Intl.DateTimeFormat('en-US', {
-    timeZone,
-    year: 'numeric',
-    month: '2-digit',
-    day: '2-digit',
-    hour: '2-digit',
-    minute: '2-digit',
-    hourCycle: 'h23',
-  }).formatToParts(date)
-  const value = (type: string) =>
-    parts.find((part) => part.type === type)?.value
-  const year = Number(value('year') ?? 0)
-  const month = Number(value('month') ?? 1)
-  const day = Number(value('day') ?? 1)
-  const hour = Number(value('hour') ?? 0)
-  const minute = Number(value('minute') ?? 0)
-  return {
-    year,
-    month,
-    day,
-    hour,
-    minute,
-  }
-}
-
-function addDaysToYmd(
-  year: number,
-  month: number,
-  day: number,
-  days: number,
-): Pick<ZonedDateParts, 'year' | 'month' | 'day'> {
-  const next = new Date(Date.UTC(year, month - 1, day))
-  next.setUTCDate(next.getUTCDate() + days)
-  return {
-    year: next.getUTCFullYear(),
-    month: next.getUTCMonth() + 1,
-    day: next.getUTCDate(),
-  }
-}
-
-function getUtcForZonedTime(
-  parts: Pick<ZonedDateParts, 'year' | 'month' | 'day'>,
-  timeZone: string,
-  hour: number,
-  minute: number,
-): Date {
-  let guess = new Date(
-    Date.UTC(parts.year, parts.month - 1, parts.day, hour, minute),
-  )
-
-  for (let i = 0; i < 3; i++) {
-    const actual = getZonedParts(guess, timeZone)
-    const desiredUtc = Date.UTC(
-      parts.year,
-      parts.month - 1,
-      parts.day,
-      hour,
-      minute,
-    )
-    const actualUtc = Date.UTC(
-      actual.year,
-      actual.month - 1,
-      actual.day,
-      actual.hour,
-      actual.minute,
-    )
-    guess = new Date(guess.getTime() + (desiredUtc - actualUtc))
-  }
-
-  return guess
-}
-
 function getNextFreebuffDeploymentStart(now: Date): Date {
   const easternNow = getZonedParts(now, FREEBUFF_EASTERN_TIMEZONE)
   const isBeforeTodayOpen = easternNow.hour < 9
diff --git a/common/src/types/freebuff-session.ts b/common/src/types/freebuff-session.ts
@@ -10,13 +10,18 @@
  * Usage counter surfaced to the CLI so the waiting-room UI can render
  * "N of M sessions used" alongside queue/active state. Present when the
  * joined model consumes premium Freebuff sessions. `recentCount` is the
- * rounded session units inside `windowHours` at the time the response was
- * produced — see also the standalone `rate_limited` status for the reject
- * path.
+ * rounded session units since the last midnight Pacific reset at the time
+ * the response was produced — see also the standalone `rate_limited` status
+ * for the reject path.
  */
 export interface FreebuffSessionRateLimit {
   model: string
   limit: number
+  period: 'pacific_day'
+  resetTimeZone: string
+  resetAt: string
+  /** Deprecated wire field kept for older clients. Premium usage now resets
+   *  at midnight Pacific time rather than using a rolling window. */
   windowHours: number
   recentCount: number
 }
@@ -63,7 +68,7 @@ export type FreebuffSessionServerResponse =
        *  produces `none`). */
       queueDepthByModel?: Record<string, number>
       /** Current quota snapshots for premium models, keyed by model id. Lets
-       *  the picker show rolling premium-session usage before the user commits
+       *  the picker show today's premium-session usage before the user commits
        *  to a queue. */
       rateLimitsByModel?: FreebuffSessionRateLimitByModel
     }
@@ -159,22 +164,23 @@ export type FreebuffSessionServerResponse =
       status: 'banned'
     }
   | {
-      /** User has used up their shared premium-session quota in the rolling
-       *  window. Returned from POST /session before the user is placed in the
-       *  queue. `retryAfterMs` is the time until enough session units fall out
-       *  of the window to open one quota slot — clients should show the user
-       *  when they can try again. Terminal for the CLI's current poll session;
-       *  the user can exit and come back later. */
+      /** User has used up their shared premium-session quota for the current
+       *  Pacific day. Returned from POST /session before the user is placed in
+       *  the queue. `retryAfterMs` is the time until the next midnight Pacific
+       *  reset. Terminal for the CLI's current poll session; the user can exit
+       *  and come back later. */
       status: 'rate_limited'
       /** The freebuff model the user tried to join. */
       model: string
-      /** Max premium session units permitted per window (e.g. 5). */
+      /** Max premium session units permitted per Pacific day (e.g. 5). */
       limit: number
-      /** Rolling window size in hours (e.g. 20). */
+      period: 'pacific_day'
+      resetTimeZone: string
+      resetAt: string
+      /** Deprecated wire field kept for older clients. */
       windowHours: number
-      /** Premium session units inside the window at check time — will be ≥ limit. */
+      /** Premium session units since today's Pacific reset — will be ≥ limit. */
       recentCount: number
-      /** Milliseconds from now until the oldest admission in the window
-       *  exits and the user regains one quota slot. */
+      /** Milliseconds from now until the next Pacific midnight reset. */
       retryAfterMs: number
     }
diff --git a/common/src/util/__tests__/zoned-time.test.ts b/common/src/util/__tests__/zoned-time.test.ts
@@ -0,0 +1,35 @@
+import { describe, expect, test } from 'bun:test'
+
+import { getZonedDayBounds } from '../zoned-time'
+
+describe('getZonedDayBounds', () => {
+  test('returns the current Pacific day bounds on a normal day', () => {
+    const bounds = getZonedDayBounds(
+      new Date('2026-04-17T16:00:00Z'),
+      'America/Los_Angeles',
+    )
+
+    expect(bounds.startsAt.toISOString()).toBe('2026-04-17T07:00:00.000Z')
+    expect(bounds.resetsAt.toISOString()).toBe('2026-04-18T07:00:00.000Z')
+  })
+
+  test('handles the shorter spring-forward Pacific day', () => {
+    const bounds = getZonedDayBounds(
+      new Date('2026-03-08T09:00:00Z'),
+      'America/Los_Angeles',
+    )
+
+    expect(bounds.startsAt.toISOString()).toBe('2026-03-08T08:00:00.000Z')
+    expect(bounds.resetsAt.toISOString()).toBe('2026-03-09T07:00:00.000Z')
+  })
+
+  test('handles the longer fall-back Pacific day', () => {
+    const bounds = getZonedDayBounds(
+      new Date('2026-11-01T09:00:00Z'),
+      'America/Los_Angeles',
+    )
+
+    expect(bounds.startsAt.toISOString()).toBe('2026-11-01T07:00:00.000Z')
+    expect(bounds.resetsAt.toISOString()).toBe('2026-11-02T08:00:00.000Z')
+  })
+})
diff --git a/common/src/util/zoned-time.ts b/common/src/util/zoned-time.ts
@@ -0,0 +1,98 @@
+export interface ZonedDateParts {
+  year: number
+  month: number
+  day: number
+  hour: number
+  minute: number
+}
+
+export function getZonedParts(date: Date, timeZone: string): ZonedDateParts {
+  const parts = new Intl.DateTimeFormat('en-US', {
+    timeZone,
+    year: 'numeric',
+    month: '2-digit',
+    day: '2-digit',
+    hour: '2-digit',
+    minute: '2-digit',
+    hourCycle: 'h23',
+  }).formatToParts(date)
+
+  const get = (type: string) => {
+    const value = parts.find((part) => part.type === type)?.value
+    if (!value) throw new Error(`Missing ${type} in ${timeZone} date parts`)
+    return Number(value)
+  }
+
+  return {
+    year: get('year'),
+    month: get('month'),
+    day: get('day'),
+    hour: get('hour'),
+    minute: get('minute'),
+  }
+}
+
+export function addDaysToYmd(
+  year: number,
+  month: number,
+  day: number,
+  days: number,
+): Pick<ZonedDateParts, 'year' | 'month' | 'day'> {
+  const next = new Date(Date.UTC(year, month - 1, day))
+  next.setUTCDate(next.getUTCDate() + days)
+  return {
+    year: next.getUTCFullYear(),
+    month: next.getUTCMonth() + 1,
+    day: next.getUTCDate(),
+  }
+}
+
+export function getUtcForZonedTime(
+  parts: Pick<ZonedDateParts, 'year' | 'month' | 'day'>,
+  timeZone: string,
+  hour: number,
+  minute: number,
+): Date {
+  let guess = new Date(
+    Date.UTC(parts.year, parts.month - 1, parts.day, hour, minute),
+  )
+
+  for (let i = 0; i < 3; i++) {
+    const actual = getZonedParts(guess, timeZone)
+    const desiredUtc = Date.UTC(
+      parts.year,
+      parts.month - 1,
+      parts.day,
+      hour,
+      minute,
+    )
+    const actualUtc = Date.UTC(
+      actual.year,
+      actual.month - 1,
+      actual.day,
+      actual.hour,
+      actual.minute,
+    )
+    guess = new Date(guess.getTime() + (desiredUtc - actualUtc))
+  }
+
+  return guess
+}
+
+export function getZonedDayBounds(
+  now: Date,
+  timeZone: string,
+): { startsAt: Date; resetsAt: Date } {
+  const nowParts = getZonedParts(now, timeZone)
+  const today = {
+    year: nowParts.year,
+    month: nowParts.month,
+    day: nowParts.day,
+  }
+  const tomorrow = addDaysToYmd(today.year, today.month, today.day, 1)
+
+  return {
+    startsAt: getUtcForZonedTime(today, timeZone, 0, 0),
+    resetsAt: getUtcForZonedTime(tomorrow, timeZone, 0, 0),
+  }
+}
diff --git a/docs/freebuff-waiting-room.md b/docs/freebuff-waiting-room.md
@@ -162,6 +162,10 @@ The final tick result carries a `queueDepthByModel` map and a single `skipped` r
 | `FREEBUFF_SESSION_LENGTH_MS` | env | 3_600_000 | Session lifetime |
 | `SESSION_GRACE_MS` | `web/src/server/free-session/config.ts` | 1_800_000 | Drain window after expiry — gate still admits requests so an in-flight agent can finish, but the CLI is expected to block new prompts. Hard cutoff at `expires_at + grace`. |
 
+### Premium Session Quota
+
+DeepSeek, Kimi, and legacy GLM share a per-user premium quota. The server counts `free_session_admit` rows from the last midnight in `America/Los_Angeles`; when the user reaches `FREEBUFF_PREMIUM_SESSION_LIMIT`, the next premium `POST /session` is rejected until the next Pacific midnight reset. MiniMax remains unlimited.
+
 ## HTTP API
 
 All endpoints authenticate via the standard `Authorization: Bearer <api-key>` or `x-codebuff-api-key` header.
diff --git a/packages/internal/src/db/schema.ts b/packages/internal/src/db/schema.ts
@@ -911,9 +911,9 @@ export const freeSession = pgTable(
 
 /**
  * Audit log of every admission — one row per queued→active transition. Used
- * to track shared premium-session usage for Freebuff's 5 sessions / 20h
- * allowance. `session_units` starts at 1.0 and may be reduced when users end
- * active sessions early.
+ * to track shared premium-session usage for Freebuff's 5 sessions per Pacific
+ * day allowance. `session_units` starts at 1.0 and may be reduced when users
+ * end active sessions early.
  *
  * Separate from `free_session` because that table is one-row-per-user (state,
  * not history); the UPSERT path there would otherwise destroy prior admissions.
diff --git a/web/src/server/free-session/__tests__/public-api.test.ts b/web/src/server/free-session/__tests__/public-api.test.ts
diff --git a/web/src/server/free-session/public-api.ts b/web/src/server/free-session/public-api.ts
