add shared comfy credit conversion helpers

src/base/credits/comfyCredits.ts

@@ -0,0 +1,142 @@
+const DEFAULT_NUMBER_FORMAT: Intl.NumberFormatOptions = {
+  minimumFractionDigits: 2,
+  maximumFractionDigits: 2
+}
+
+const formatNumber = ({
+  value,
+  locale,
+  options
+}: {
+  value: number
+  locale?: string
+  options?: Intl.NumberFormatOptions
+}): string => {
+  const merged: Intl.NumberFormatOptions = {
+    ...DEFAULT_NUMBER_FORMAT,
+    ...options
+  }
+
+  if (
+    typeof merged.maximumFractionDigits === 'number' &&
+    typeof merged.minimumFractionDigits === 'number' &&
+    merged.maximumFractionDigits < merged.minimumFractionDigits
+  ) {
+    merged.minimumFractionDigits = merged.maximumFractionDigits
+  }
+
+  return new Intl.NumberFormat(locale, merged).format(value)
+}
+
+export const CREDITS_PER_USD = 211
+export const COMFY_CREDIT_RATE_CENTS = CREDITS_PER_USD / 100 // credits per cent
+
+export const usdToCents = (usd: number): number => Math.round(usd * 100)
+
+export const centsToCredits = (cents: number): number =>
+  Math.round(cents * COMFY_CREDIT_RATE_CENTS)
+
+export const creditsToCents = (credits: number): number =>
+  Math.round(credits / COMFY_CREDIT_RATE_CENTS)
+
+export const usdToCredits = (usd: number): number =>
+  Math.round(usd * CREDITS_PER_USD)
+
+export const creditsToUsd = (credits: number): number =>
+  Math.round((credits / CREDITS_PER_USD) * 100) / 100
+
+export type FormatOptions = {
+  value: number
+  locale?: string
+  numberOptions?: Intl.NumberFormatOptions
+}
+
+export type FormatFromCentsOptions = {
+  cents: number
+  locale?: string
+  numberOptions?: Intl.NumberFormatOptions
+}
+
+export type FormatFromUsdOptions = {
+  usd: number
+  locale?: string
+  numberOptions?: Intl.NumberFormatOptions
+}
+
+export const formatCredits = ({
+  value,
+  locale,
+  numberOptions
+}: FormatOptions): string =>
+  formatNumber({ value, locale, options: numberOptions })
+
+export const formatCreditsFromCents = ({
+  cents,
+  locale,
+  numberOptions
+}: FormatFromCentsOptions): string =>
+  formatCredits({
+    value: centsToCredits(cents),
+    locale,
+    numberOptions
+  })
+
+export const formatCreditsFromUsd = ({
+  usd,
+  locale,
+  numberOptions
+}: FormatFromUsdOptions): string =>
+  formatCredits({
+    value: usdToCredits(usd),
+    locale,
+    numberOptions
+  })
+
+// Special conversion for subscription backend data
+// Backend sends values as "micros" but they are really in a special format where 211 units = 1 credit
+export const formatCreditsFromSubscriptionMicros = ({
+  micros,
+  locale,
+  numberOptions
+}: {
+  micros: number
+  locale?: string
+  numberOptions?: Intl.NumberFormatOptions
+}): string =>
+  formatCredits({
+    value: micros / CREDITS_PER_USD,
+    locale,
+    numberOptions
+  })
+
+export const formatUsd = ({
+  value,
+  locale,
+  numberOptions
+}: FormatOptions): string =>
+  formatNumber({
+    value,
+    locale,
+    options: numberOptions
+  })
+
+export const formatUsdFromCents = ({
+  cents,
+  locale,
+  numberOptions
+}: FormatFromCentsOptions): string =>
+  formatUsd({
+    value: cents / 100,
+    locale,
+    numberOptions
+  })
+
+/**
+ * Clamps a USD value to the allowed range for credit purchases
+ * @param value - The USD amount to clamp
+ * @returns The clamped value between $1 and $1000, or 0 if NaN
+ */
+export const clampUsd = (value: number): number => {
+  if (Number.isNaN(value)) return 0
+  return Math.min(1000, Math.max(1, value))
+}

src/components/common/UserCredit.vue

@@ -26,10 +26,11 @@
 import Skeleton from 'primevue/skeleton'
 import Tag from 'primevue/tag'
 import { computed } from 'vue'
+import { useI18n } from 'vue-i18n'
 
+import { formatCreditsFromCents } from '@/base/credits/comfyCredits'
 import { useFeatureFlags } from '@/composables/useFeatureFlags'
 import { useFirebaseAuthStore } from '@/stores/firebaseAuthStore'
-import { formatMetronomeCurrency } from '@/utils/formatUtil'
 
 const { textClass } = defineProps<{
   textClass?: string
@@ -38,9 +39,15 @@ const { textClass } = defineProps<{
 const authStore = useFirebaseAuthStore()
 const { flags } = useFeatureFlags()
 const balanceLoading = computed(() => authStore.isFetchingBalance)
+const { t, locale } = useI18n()
 
 const formattedBalance = computed(() => {
-  if (!authStore.balance) return '0.00'
-  return formatMetronomeCurrency(authStore.balance.amount_micros, 'usd')
+  // Backend returns cents despite the *_micros naming convention.
+  const cents = authStore.balance?.amount_micros ?? 0
+  const amount = formatCreditsFromCents({
+    cents,
+    locale: locale.value
+  })
+  return `${amount} ${t('credits.credits')}`
 })
 </script>

src/components/dialog/content/TopUpCreditsDialogContent.stories.ts

@@ -0,0 +1,41 @@
+import type { Meta, StoryObj } from '@storybook/vue3-vite'
+
+import TopUpCreditsDialogContent from './TopUpCreditsDialogContent.vue'
+
+interface TopUpCreditsStoryArgs {
+  refreshDate?: string
+}
+
+const meta: Meta<TopUpCreditsStoryArgs> = {
+  title: 'Components/Dialog/TopUpCreditsDialogContent',
+  component: TopUpCreditsDialogContent,
+  argTypes: {
+    refreshDate: {
+      control: 'text',
+      description: 'Date when credits refresh'
+    }
+  },
+  parameters: {
+    docs: {
+      description: {
+        component:
+          'Credit top-up dialog content. Design is controlled by the `subscription_tiers_enabled` feature flag (defaults to new design).'
+      }
+    }
+  }
+}
+
+export default meta
+type Story = StoryObj<typeof meta>
+
+export const Default: Story = {
+  args: {
+    refreshDate: 'Dec 16, 2025'
+  }
+}
+
+export const WithoutRefreshDate: Story = {
+  args: {
+    refreshDate: undefined
+  }
+}