From 16204d30f812f9d65368c4780b2e0755d6ef627c Mon Sep 17 00:00:00 2001
From: "Calum H." <calum@modrinth.com>
Date: Wed, 4 Feb 2026 14:56:14 +0000
Subject: [PATCH] fix: withdraw flow fixes (#5296)

* fix: dev-741 currency exchanging bug

* fix: remove redundant balance available check

* fix: lint/fmt

* fix: #5245

* fix: hide max if it's less than min
---
 .../TremendousDetailsStage.vue                | 227 ++++++++++++++----
 .../src/providers/creator-withdraw.ts         |  19 +-
 apps/labrinth/src/routes/v3/payouts.rs        |   8 +-
 3 files changed, 196 insertions(+), 58 deletions(-)

diff --git a/apps/frontend/src/components/ui/dashboard/withdraw-stages/TremendousDetailsStage.vue b/apps/frontend/src/components/ui/dashboard/withdraw-stages/TremendousDetailsStage.vue
index 7835c7cdb..d33d0662f 100644
--- a/apps/frontend/src/components/ui/dashboard/withdraw-stages/TremendousDetailsStage.vue
+++ b/apps/frontend/src/components/ui/dashboard/withdraw-stages/TremendousDetailsStage.vue
@@ -90,66 +90,41 @@
 				</Combobox>
 			</div>
 			<span v-if="selectedMethodDetails" class="text-secondary">
-				{{
-					formatMoney(
-						selectedMethodCurrencyCode &&
-							selectedMethodCurrencyCode !== 'USD' &&
-							selectedMethodExchangeRate
-							? (fixedDenominationMin ?? effectiveMinAmount) / selectedMethodExchangeRate
-							: (fixedDenominationMin ?? effectiveMinAmount),
-					)
-				}}<template v-if="selectedMethodCurrencyCode && selectedMethodCurrencyCode !== 'USD'">
-					({{
+				{{ formatMoney(displayMinUsd)
+				}}<template v-if="selectedMethodCurrencyCode && selectedMethodCurrencyCode !== 'USD'"
+					>({{
 						formatAmountForDisplay(
-							fixedDenominationMin ?? effectiveMinAmount,
+							displayMinLocal,
 							selectedMethodCurrencyCode,
 							selectedMethodExchangeRate,
 						)
 					}})</template
 				>
-				min,
-				{{
-					formatMoney(
-						selectedMethodCurrencyCode &&
-							selectedMethodCurrencyCode !== 'USD' &&
-							selectedMethodExchangeRate
-							? (fixedDenominationMax ??
-									selectedMethodDetails.interval?.standard?.max ??
-									effectiveMaxAmount) / selectedMethodExchangeRate
-							: (fixedDenominationMax ??
-									selectedMethodDetails.interval?.standard?.max ??
-									effectiveMaxAmount),
-					)
-				}}<template v-if="selectedMethodCurrencyCode && selectedMethodCurrencyCode !== 'USD'">
-					({{
-						formatAmountForDisplay(
-							fixedDenominationMax ??
-								selectedMethodDetails.interval?.standard?.max ??
-								effectiveMaxAmount,
-							selectedMethodCurrencyCode,
-							selectedMethodExchangeRate,
-						)
-					}})</template
+				min<template v-if="displayMinUsd <= roundedMaxAmount"
+					>, {{ formatMoney(displayMaxUsd)
+					}}<template v-if="selectedMethodCurrencyCode && selectedMethodCurrencyCode !== 'USD'"
+						>({{
+							formatAmountForDisplay(
+								displayMaxLocal,
+								selectedMethodCurrencyCode,
+								selectedMethodExchangeRate,
+							)
+						}})</template
+					>
+					max</template
 				>
-				max withdrawal amount.
+				withdrawal amount.
 			</span>
 			<span
 				v-if="selectedMethodDetails && effectiveMinAmount > roundedMaxAmount"
 				class="text-sm text-red"
 			>
 				You need at least
-				{{
-					formatMoney(
-						selectedMethodCurrencyCode &&
-							selectedMethodCurrencyCode !== 'USD' &&
-							selectedMethodExchangeRate
-							? effectiveMinAmount / selectedMethodExchangeRate
-							: effectiveMinAmount,
-					)
-				}}<template v-if="selectedMethodCurrencyCode && selectedMethodCurrencyCode !== 'USD'">
-					({{
+				{{ formatMoney(displayMinUsd)
+				}}<template v-if="selectedMethodCurrencyCode && selectedMethodCurrencyCode !== 'USD'"
+					>({{
 						formatAmountForDisplay(
-							effectiveMinAmount,
+							displayMinLocal,
 							selectedMethodCurrencyCode,
 							selectedMethodExchangeRate,
 						)
@@ -307,7 +282,19 @@
 					v-if="!useDenominationSuggestions && denominationOptions.length === 0"
 					class="text-error text-sm"
 				>
-					No denominations available for your current balance
+					<template v-if="rawFixedDenominationMin !== null">
+						The minimum denomination is
+						{{
+							formatAmountForDisplay(
+								rawFixedDenominationMin,
+								selectedMethodCurrencyCode,
+								selectedMethodExchangeRate,
+							)
+						}}<template v-if="selectedMethodCurrencyCode && selectedMethodCurrencyCode !== 'USD'">
+							({{ formatMoney(convertToUsd(rawFixedDenominationMin)) }})</template
+						>, which exceeds your balance of {{ formatMoney(roundedMaxAmount) }}.
+					</template>
+					<template v-else>No denominations available for your current balance</template>
 				</span>
 			</div>
 
@@ -324,7 +311,7 @@
 
 			<WithdrawFeeBreakdown
 				v-if="allRequiredFieldsFilled && formData.amount && formData.amount > 0"
-				:amount="formData.amount || 0"
+				:amount="amountForFeeBreakdown"
 				:fee="calculatedFee"
 				:fee-loading="feeLoading"
 				:exchange-rate="showGiftCardSelector ? selectedMethodExchangeRate : giftCardExchangeRate"
@@ -720,6 +707,34 @@ const hasSelectedDenomination = computed(() => {
 	)
 })
 
+// Convert local currency amount to USD using the selected method's exchange rate
+const convertToUsd = (localAmount: number): number => {
+	const exchangeRate = selectedMethodExchangeRate.value
+	if (
+		selectedMethodCurrencyCode.value &&
+		selectedMethodCurrencyCode.value !== 'USD' &&
+		exchangeRate &&
+		exchangeRate > 0
+	) {
+		return localAmount / exchangeRate
+	}
+	return localAmount
+}
+
+// Convert USD amount to local currency using the selected method's exchange rate
+const convertToLocalCurrency = (usdAmount: number): number => {
+	const exchangeRate = selectedMethodExchangeRate.value
+	if (
+		selectedMethodCurrencyCode.value &&
+		selectedMethodCurrencyCode.value !== 'USD' &&
+		exchangeRate &&
+		exchangeRate > 0
+	) {
+		return usdAmount * exchangeRate
+	}
+	return usdAmount
+}
+
 const denominationOptions = computed(() => {
 	const interval = selectedMethodDetails.value?.interval
 	if (!interval) return []
@@ -735,30 +750,56 @@ const denominationOptions = computed(() => {
 
 	if (values.length === 0) return []
 
-	const filtered = values.filter((amount) => amount <= roundedMaxAmount.value).sort((a, b) => a - b)
+	// Convert USD balance to local currency for comparison with denomination values
+	// (denomination values are in local currency, e.g., 50 INR, 45000 IDR)
+	const maxInLocalCurrency = convertToLocalCurrency(roundedMaxAmount.value)
+
+	const filtered = values.filter((amount) => amount <= maxInLocalCurrency).sort((a, b) => a - b)
 	debug(
 		'Denomination options (filtered by max):',
 		filtered,
 		'from',
 		values,
-		'max:',
+		'max (local currency):',
+		maxInLocalCurrency,
+		'max (USD):',
 		roundedMaxAmount.value,
 	)
 	return filtered
 })
 
 const effectiveMinAmount = computed(() => {
-	return selectedMethodDetails.value?.interval?.standard?.min || 0.01
+	const min = selectedMethodDetails.value?.interval?.standard?.min || 0.01
+	// Convert from local currency to USD for display/validation
+	return convertToUsd(min)
 })
 
 const effectiveMaxAmount = computed(() => {
 	const methodMax = selectedMethodDetails.value?.interval?.standard?.max
 	if (methodMax !== undefined && methodMax !== null) {
-		return Math.min(roundedMaxAmount.value, methodMax)
+		// Convert method max from local currency to USD, then compare with USD balance
+		const methodMaxInUsd = convertToUsd(methodMax)
+		return Math.min(roundedMaxAmount.value, methodMaxInUsd)
 	}
 	return roundedMaxAmount.value
 })
 
+// Get the minimum fixed denomination from the full list (not filtered by user balance)
+const rawFixedDenominationMin = computed(() => {
+	const interval = selectedMethodDetails.value?.interval
+	if (!interval) return null
+
+	let values: number[] = []
+	if (interval.fixed?.values) {
+		values = [...interval.fixed.values]
+	} else if (interval.standard && interval.standard.min === interval.standard.max) {
+		values = [interval.standard.min]
+	}
+
+	if (values.length === 0) return null
+	return Math.min(...values)
+})
+
 const fixedDenominationMin = computed(() => {
 	if (!useFixedDenominations.value) return null
 	const options = denominationOptions.value
@@ -773,6 +814,63 @@ const fixedDenominationMax = computed(() => {
 	return options[options.length - 1]
 })
 
+// - Fixed denominations: convert from local currency to USD
+// - Variable amounts: effectiveMinAmount/effectiveMaxAmount are already in USD
+const displayMinUsd = computed(() => {
+	if (fixedDenominationMin.value !== null) {
+		// Fixed denomination is in local currency, convert to USD
+		return convertToUsd(fixedDenominationMin.value)
+	}
+	// If no affordable denominations but there are fixed values, show the raw minimum
+	if (rawFixedDenominationMin.value !== null) {
+		return convertToUsd(rawFixedDenominationMin.value)
+	}
+	// effectiveMinAmount is already in USD
+	return effectiveMinAmount.value
+})
+
+const displayMaxUsd = computed(() => {
+	if (fixedDenominationMax.value !== null) {
+		// Fixed denomination is in local currency, convert to USD
+		return convertToUsd(fixedDenominationMax.value)
+	}
+	// For variable amounts, use effectiveMaxAmount (already in USD)
+	// But also check if there's a method max from the interval
+	const methodMax = selectedMethodDetails.value?.interval?.standard?.max
+	if (methodMax !== undefined && methodMax !== null) {
+		const methodMaxUsd = convertToUsd(methodMax)
+		return Math.min(effectiveMaxAmount.value, methodMaxUsd)
+	}
+	return effectiveMaxAmount.value
+})
+
+// Display values in local currency (for showing in parentheses)
+const displayMinLocal = computed(() => {
+	if (fixedDenominationMin.value !== null) {
+		// Fixed denomination is already in local currency
+		return fixedDenominationMin.value
+	}
+	// If no affordable denominations but there are fixed values, show the raw minimum
+	if (rawFixedDenominationMin.value !== null) {
+		return rawFixedDenominationMin.value
+	}
+	// Convert USD to local currency
+	return convertToLocalCurrency(effectiveMinAmount.value)
+})
+
+const displayMaxLocal = computed(() => {
+	if (fixedDenominationMax.value !== null) {
+		// Fixed denomination is already in local currency
+		return fixedDenominationMax.value
+	}
+	// Check for method max
+	const methodMax = selectedMethodDetails.value?.interval?.standard?.max
+	if (methodMax !== undefined && methodMax !== null) {
+		return Math.min(convertToLocalCurrency(effectiveMaxAmount.value), methodMax)
+	}
+	return convertToLocalCurrency(effectiveMaxAmount.value)
+})
+
 const selectedDenomination = computed({
 	get: () => formData.value.amount,
 	set: (value) => {
@@ -791,6 +889,21 @@ const allRequiredFieldsFilled = computed(() => {
 	return true
 })
 
+// Amount to display in WithdrawFeeBreakdown (expects local currency for gift cards)
+const amountForFeeBreakdown = computed(() => {
+	const amount = formData.value.amount ?? 0
+	if (!showGiftCardSelector.value) {
+		// Non-gift-card: amount is in USD
+		return amount
+	}
+	if (useFixedDenominations.value) {
+		// Fixed denominations: amount is already in local currency
+		return amount
+	}
+	// Variable amount gift card: amount is in USD, convert to local currency
+	return convertToLocalCurrency(amount)
+})
+
 const calculateFeesDebounced = useDebounceFn(async () => {
 	const amount = formData.value.amount
 	if (!amount || amount <= 0) {
@@ -852,7 +965,15 @@ watch(
 watch(
 	[() => formData.value.amount, selectedGiftCardId, deliveryEmail, selectedCurrency],
 	() => {
-		withdrawData.value.calculation.amount = formData.value.amount ?? 0
+		let amountForBackend = formData.value.amount ?? 0
+
+		// - Fixed denominations (chips): formData.amount is already in local currency
+		// - Variable amounts (RevenueInputField): formData.amount is in USD, needs conversion
+		if (showGiftCardSelector.value && !useFixedDenominations.value && amountForBackend > 0) {
+			amountForBackend = convertToLocalCurrency(amountForBackend)
+		}
+
+		withdrawData.value.calculation.amount = amountForBackend
 
 		if (showGiftCardSelector.value && selectedGiftCardId.value) {
 			withdrawData.value.selection.methodId = selectedGiftCardId.value
diff --git a/apps/frontend/src/providers/creator-withdraw.ts b/apps/frontend/src/providers/creator-withdraw.ts
index 0f16842bc..b07cc0bfe 100644
--- a/apps/frontend/src/providers/creator-withdraw.ts
+++ b/apps/frontend/src/providers/creator-withdraw.ts
@@ -651,15 +651,27 @@ export function createWithdrawContext(
 				)
 
 				if (selectedMethod?.interval) {
-					const userMax = Math.floor(maxWithdrawAmount.value * 100) / 100
+					const userMaxUsd = Math.floor(maxWithdrawAmount.value * 100) / 100
+
+					const exchangeRate = selectedMethod.exchange_rate
+					const isNonUsdCurrency =
+						selectedMethod.currency_code &&
+						selectedMethod.currency_code !== 'USD' &&
+						exchangeRate &&
+						exchangeRate > 0
+
+					const userMaxInLocalCurrency = isNonUsdCurrency ? userMaxUsd * exchangeRate : userMaxUsd
+
 					if (selectedMethod.interval.standard) {
 						const { min, max } = selectedMethod.interval.standard
-						const effectiveMax = Math.min(userMax, max)
+						const effectiveMax = Math.min(userMaxInLocalCurrency, max)
 						const effectiveMin = Math.min(min, effectiveMax)
 						if (amount < effectiveMin || amount > effectiveMax) return false
 					}
 					if (selectedMethod.interval.fixed) {
-						const validValues = selectedMethod.interval.fixed.values.filter((v) => v <= userMax)
+						const validValues = selectedMethod.interval.fixed.values.filter(
+							(v) => v <= userMaxInLocalCurrency,
+						)
 						if (!validValues.includes(amount)) return false
 					}
 				}
@@ -817,6 +829,7 @@ export function createWithdrawContext(
 			calculation: {
 				amount: 0,
 				fee: null,
+				netUsd: null,
 				exchangeRate: null,
 			},
 			providerData: {
diff --git a/apps/labrinth/src/routes/v3/payouts.rs b/apps/labrinth/src/routes/v3/payouts.rs
index 37a0596da..667c32dda 100644
--- a/apps/labrinth/src/routes/v3/payouts.rs
+++ b/apps/labrinth/src/routes/v3/payouts.rs
@@ -498,9 +498,13 @@ pub async fn create_payout(
     let balance = get_user_balance(user.id, &pool)
         .await
         .wrap_internal_err("failed to calculate user balance")?;
-    if balance.available < body.amount || body.amount < Decimal::ZERO {
+
+    // Note: We only check for negative amounts here. The full balance validation
+    // happens later in payout_flow.validate() which correctly handles currency
+    // conversion (body.amount may be in local currency for gift cards, not USD).
+    if body.amount < Decimal::ZERO {
         return Err(ApiError::InvalidInput(
-            "You do not have enough funds to make this payout!".to_string(),
+            "Amount must be positive!".to_string(),
         ));
     }