fix: 修复兑换码额度精度损失 (#6685)

* fix: 修复兑换码额度精度损失(#6680)

* fix(redemption): guard update data integrity

web/src/lib/currency.ts

@@ -244,6 +244,23 @@ function mergeOptions(
   }
 }
 
+function getFractionDigits(
+  value: number,
+  digitsLarge: number,
+  digitsSmall: number
+): number {
+  return Math.abs(value) >= 1 ? digitsLarge : digitsSmall
+}
+
+/** Return the configured fraction digits for a plain currency value. */
+export function getCurrencyFractionDigits(
+  value: number,
+  options?: CurrencyFormatOptions
+): number {
+  const merged = mergeOptions(options)
+  return getFractionDigits(value, merged.digitsLarge, merged.digitsSmall)
+}
+
 function removeTrailingZeros(str: string): string {
   if (!str.includes('.')) return str
   return str.replace(/(\.[0-9]*?)0+$/, '$1').replace(/\.$/, '')
@@ -261,7 +278,7 @@ function formatNumberWithSuffix(
     return `${removeTrailingZeros(result.toFixed(1))}k`
   }
 
-  const digits = abs >= 1 ? digitsLarge : digitsSmall
+  const digits = getFractionDigits(value, digitsLarge, digitsSmall)
   return removeTrailingZeros(value.toFixed(digits))
 }
 
@@ -300,8 +317,11 @@ function formatCurrencyValue(
     )
   }
 
-  const digits =
-    Math.abs(value) >= 1 ? options.digitsLarge : options.digitsSmall
+  const digits = getFractionDigits(
+    value,
+    options.digitsLarge,
+    options.digitsSmall
+  )
   const adjustedValue = adjustForMinimum(value, digits, options.minimumNonZero)
 
   if (meta.kind === 'currency') {

web/src/lib/format.ts

@@ -22,6 +22,7 @@ import {
   formatCurrencyFromUSD,
   formatQuotaWithCurrency,
   getCurrencyDisplay,
+  getCurrencyFractionDigits,
 } from './currency'
 
 // ============================================================================
@@ -104,16 +105,44 @@ export function parseQuotaFromDollars(amount: number): number {
  */
 export function quotaUnitsToDollars(units: number): number {
   const { config, meta } = getCurrencyDisplay()
+  return quotaUnitsToDisplayAmount(units, config.quotaPerUnit, meta)
+}
 
+function quotaUnitsToDisplayAmount(
+  units: number,
+  quotaPerUnit: number,
+  meta: ReturnType<typeof getCurrencyDisplay>['meta']
+): number {
   if (meta.kind === 'tokens') {
     return units
   }
 
-  const usdAmount = units / config.quotaPerUnit
-  const exchangeRate =
-    meta.kind === 'currency' || meta.kind === 'custom' ? meta.exchangeRate : 1
+  return (units / quotaPerUnit) * meta.exchangeRate
+}
 
-  return usdAmount * exchangeRate
+/**
+ * Convert quota units to a plain number suitable for an editable input.
+ * Uses the same precision as quota list formatting without symbols or suffixes.
+ */
+export function quotaUnitsToEditableAmount(units: number): number {
+  const { config, meta } = getCurrencyDisplay()
+  const amount = quotaUnitsToDisplayAmount(units, config.quotaPerUnit, meta)
+
+  if (meta.kind === 'tokens') {
+    return Math.round(amount)
+  }
+
+  return Number(amount.toFixed(getCurrencyFractionDigits(amount)))
+}
+
+/** Return the input step matching the configured editable quota precision. */
+export function getEditableQuotaStep(): number {
+  const { meta } = getCurrencyDisplay()
+  if (meta.kind === 'tokens') {
+    return 1
+  }
+
+  return 10 ** -getCurrencyFractionDigits(0)
 }
 
 // ============================================================================