fix(ai-chat): show reset date for future credits

apps/desktop/layer/renderer/src/modules/ai-chat/utils/rate-limit.test.ts

@@ -0,0 +1,78 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest"
+
+import { computeRateLimitMessage } from "./rate-limit"
+
+vi.mock("~/i18n", () => ({
+  getI18n: () => ({
+    language: "en-GB",
+    resolvedLanguage: "en-GB",
+    t: (key: string, options?: Record<string, unknown>) => {
+      switch (key) {
+        case "rate_limit.depleted": {
+          return "AI credits depleted"
+        }
+        case "rate_limit.minute": {
+          return "minute"
+        }
+        case "rate_limit.minutes": {
+          return "minutes"
+        }
+        case "rate_limit.resets_at": {
+          return `resets at ${options?.time as string}`
+        }
+        case "rate_limit.resets_in": {
+          return `resets in ${options?.value as string}`
+        }
+        case "rate_limit.credits_left": {
+          return `${options?.count as number} credits left`
+        }
+        case "rate_limit.upgrade_to_get_more": {
+          return "Start free trial to get more AI credits."
+        }
+        default: {
+          return key
+        }
+      }
+    },
+  }),
+}))
+
+describe("computeRateLimitMessage", () => {
+  beforeEach(() => {
+    vi.useFakeTimers()
+  })
+
+  afterEach(() => {
+    vi.useRealTimers()
+  })
+
+  it("shows only the time when credits reset later today", () => {
+    vi.setSystemTime(new Date(2026, 3, 10, 8, 0))
+
+    const message = computeRateLimitMessage(undefined, {
+      usage: {
+        total: 5_000_000,
+        used: 5_000_000,
+        remaining: 0,
+        resetAt: new Date(2026, 3, 10, 20, 45),
+      },
+    })
+
+    expect(message).toBe("AI credits depleted · resets at 20:45")
+  })
+
+  it("includes the date when credits reset on a future day", () => {
+    vi.setSystemTime(new Date(2026, 3, 10, 8, 0))
+
+    const message = computeRateLimitMessage(undefined, {
+      usage: {
+        total: 5_000_000,
+        used: 5_000_000,
+        remaining: 0,
+        resetAt: new Date(2026, 3, 12, 20, 45),
+      },
+    })
+
+    expect(message).toBe("AI credits depleted · resets at 12 Apr, 20:45")
+  })
+})

apps/desktop/layer/renderer/src/modules/ai-chat/utils/rate-limit.ts

@@ -20,6 +20,7 @@ const formatResetTime = (windowResetTime: Date) => {
   const now = new Date()
   const diffMs = resetDate.getTime() - now.getTime()
   const diffMinutes = Math.ceil(diffMs / (1000 * 60))
+  const locale = i18n.language || i18n.resolvedLanguage || undefined
 
   if (diffMinutes < 60 && diffMinutes > 0) {
     const unit =
@@ -30,12 +31,31 @@ const formatResetTime = (windowResetTime: Date) => {
     return t("rate_limit.resets_in", { ns: "ai", value })
   }
 
-  const timeFormatter = new Intl.DateTimeFormat("en-GB", {
+  const isSameCalendarDay =
+    resetDate.getFullYear() === now.getFullYear() &&
+    resetDate.getMonth() === now.getMonth() &&
+    resetDate.getDate() === now.getDate()
+
+  const time = new Intl.DateTimeFormat(locale, {
     hour: "2-digit",
     minute: "2-digit",
     hour12: false,
-  })
-  return t("rate_limit.resets_at", { ns: "ai", time: timeFormatter.format(resetDate) })
+  }).format(resetDate)
+
+  if (isSameCalendarDay) {
+    return t("rate_limit.resets_at", { ns: "ai", time })
+  }
+
+  const dateTime = new Intl.DateTimeFormat(locale, {
+    ...(resetDate.getFullYear() !== now.getFullYear() ? { year: "numeric" as const } : {}),
+    month: "short",
+    day: "numeric",
+    hour: "2-digit",
+    minute: "2-digit",
+    hour12: false,
+  }).format(resetDate)
+
+  return t("rate_limit.resets_at", { ns: "ai", time: dateTime })
 }
 
 export function computeIsRateLimited(