Unify card selection UI via reusable CardSelection component; fix Buy a Gift Card new-card bug

Create CardSelection.svelte reusable component encapsulating the standard
saved-card list + 'Use a new card' + CardInput pattern with blur-based
validation (Luhn, expiry, CVC) — identical to the tip flows and account page.

Refactor UserPaymentModal (Make a Payment submodal) to use CardSelection:
- Removed its bespoke 'Use a different card' expand/collapse UI and inline
  validation derivations (parseExpiryParts, isValidLuhn, touched state)
- Bound selectedCardId + new card fields to the component
- payButtonDisabled now driven by component's onValidityChange callback
- Removed now-unused CardInput import, SvelteDate import, formatCardExpiry

Fix account 'Buy a Gift Card' bug: 'Use a new card' click did nothing because
the auto-select effect immediately re-set buySelectedCard back to the default
card. Added buyShowNewCard flag so the effect only auto-selects on initial load;
reset after successful new-card purchase so the next purchase re-defaults.

frontend/src/lib/components/payments/CardSelection.svelte

@@ -0,0 +1,202 @@
+<script lang="ts">
+	import { SvelteDate } from 'svelte/reactivity';
+	import CardInput from './CardInput.svelte';
+	import CardBrandIcon from './CardBrandIcon.svelte';
+
+	export interface SelectableCard {
+		id: string;
+		brand: string;
+		last_4: string;
+		exp_month: number;
+		exp_year: number;
+		is_default?: boolean;
+	}
+
+	let {
+		cards = [],
+		canSaveCards = false,
+		selectedCardId = $bindable(''),
+		newCardNumber = $bindable(''),
+		newCardExpiry = $bindable(''),
+		newCardCVC = $bindable(''),
+		saveCard = $bindable(false),
+		onValidityChange = (_valid: boolean) => {}
+	}: {
+		cards?: SelectableCard[];
+		canSaveCards?: boolean;
+		selectedCardId?: string;
+		newCardNumber?: string;
+		newCardExpiry?: string;
+		newCardCVC?: string;
+		saveCard?: boolean;
+		onValidityChange?: (valid: boolean) => void;
+	} = $props();
+
+	// Internal — whether the "use a new card" form is shown.
+	// When no saved cards exist the form shows by default.
+	let showNewCardForm = $state(false);
+
+	// Blur-based validation state (matches the pattern used across all card flows)
+	let cardNumberTouched = $state(false);
+	let cardExpiryTouched = $state(false);
+	let cardCVCTouched = $state(false);
+
+	function parseExpiryParts(value: string): { month: number; year: number } | null {
+		if (!/^\d{2}\/\d{2}$/.test(value)) return null;
+		const [monthStr, yearStr] = value.split('/');
+		const month = parseInt(monthStr, 10);
+		const year = 2000 + parseInt(yearStr, 10);
+		if (month < 1 || month > 12) return null;
+		return { month, year };
+	}
+
+	const expiryParts = $derived(parseExpiryParts(newCardExpiry));
+
+	const isExpiryInPast = $derived(
+		expiryParts !== null &&
+			(() => {
+				const expiryYearMonth = expiryParts.year * 12 + expiryParts.month;
+				const now = new SvelteDate();
+				const currentYearMonth = now.getFullYear() * 12 + now.getMonth() + 1;
+				return expiryYearMonth < currentYearMonth;
+			})()
+	);
+
+	const hasInvalidMonth = $derived(/^\d{2}\/\d{2}$/.test(newCardExpiry) && expiryParts === null);
+
+	function isValidLuhn(cardNumber: string): boolean {
+		const s = cardNumber.replace(/\D/g, '');
+		let sum = 0;
+		let alternate = false;
+		for (let i = s.length - 1; i >= 0; i--) {
+			let n = parseInt(s[i], 10);
+			if (alternate) {
+				n *= 2;
+				if (n > 9) n -= 9;
+			}
+			sum += n;
+			alternate = !alternate;
+		}
+		return sum % 10 === 0 && s.length >= 13 && s.length <= 19;
+	}
+
+	function handleFieldBlur(field: string) {
+		if (field === 'cardNumber') cardNumberTouched = true;
+		else if (field === 'cardExpiry') cardExpiryTouched = true;
+		else if (field === 'cardCVC') cardCVCTouched = true;
+	}
+
+	function handleFieldInput(field: string) {
+		if (field === 'cardNumber') cardNumberTouched = false;
+		else if (field === 'cardExpiry') cardExpiryTouched = false;
+		else if (field === 'cardCVC') cardCVCTouched = false;
+	}
+
+	// Exposed derived state — same semantics as the other card flows.
+	const cardError = $derived(
+		showNewCardForm || cards.length === 0
+			? cardNumberTouched && !isValidLuhn(newCardNumber) && newCardNumber.length > 0
+				? 'Invalid card number'
+				: cardExpiryTouched && hasInvalidMonth
+					? 'Invalid expiry month'
+					: cardExpiryTouched && isExpiryInPast
+						? 'This card has expired'
+						: cardExpiryTouched && newCardExpiry.length > 0 && !/^\d{2}\/\d{2}$/.test(newCardExpiry)
+							? 'Enter expiry as MM/YY'
+							: cardCVCTouched && newCardCVC.length < 3 && newCardCVC.length > 0
+								? 'Enter your CVC number'
+								: isValidLuhn(newCardNumber) &&
+									  /^\d{2}\/\d{2}$/.test(newCardExpiry) &&
+									  newCardCVC.length >= 3
+									? null
+									: newCardNumber.length === 0 &&
+										  newCardExpiry.length === 0 &&
+										  newCardCVC.length === 0
+										? null
+										: 'Please complete all card fields'
+			: null
+	);
+
+	const isCardValid = $derived(
+		(selectedCardId !== '' && cards.length > 0) ||
+			(isValidLuhn(newCardNumber) &&
+				expiryParts !== null &&
+				!isExpiryInPast &&
+				newCardCVC.length >= 3)
+	);
+
+	$effect(() => {
+		onValidityChange(isCardValid);
+	});
+</script>
+
+{#if cards.length > 0}
+	<div class="space-y-2">
+		{#each cards as card (card.id)}
+			<button
+				type="button"
+				class="flex w-full items-center justify-between rounded-lg border p-3 text-left {selectedCardId ===
+					card.id && !showNewCardForm
+					? 'border-input bg-accent'
+					: 'border-gray-200 hover:bg-gray-50'}"
+				onclick={() => {
+					selectedCardId = card.id;
+					showNewCardForm = false;
+				}}
+			>
+				<div class="flex items-center gap-3">
+					<CardBrandIcon brand={card.brand} />
+					<div class="text-sm">
+						<span class="font-mono">**** {card.last_4}</span>
+						<span class="ml-2 text-xs text-gray-400"
+							>Exp {String(card.exp_month).padStart(2, '0')}/{card.exp_year}</span
+						>
+					</div>
+				</div>
+				{#if selectedCardId === card.id && !showNewCardForm}
+					<span class="text-xs font-semibold text-primary">Selected</span>
+				{/if}
+			</button>
+		{/each}
+
+		<button
+			type="button"
+			class="flex w-full items-center justify-between rounded-lg border p-3 text-left {showNewCardForm
+				? 'border-input bg-accent'
+				: 'border-gray-200 hover:bg-gray-50'}"
+			onclick={() => {
+				selectedCardId = '';
+				showNewCardForm = true;
+			}}
+		>
+			<div class="flex items-center gap-3">
+				<div
+					class="flex h-8 min-w-12 items-center justify-center rounded border border-dashed border-gray-300 text-xs font-medium text-gray-400"
+				>
+					NEW
+				</div>
+				<span class="animate-pulse text-sm font-medium text-gray-700">Use a new card</span>
+			</div>
+			{#if showNewCardForm}
+				<span class="text-xs font-semibold text-primary">Selected</span>
+			{/if}
+		</button>
+	</div>
+{/if}
+
+{#if showNewCardForm || cards.length === 0}
+	<div class="space-y-3 rounded-lg border bg-gray-50 p-3">
+		<CardInput
+			bind:cardNumber={newCardNumber}
+			bind:cardExpiry={newCardExpiry}
+			bind:cardCVC={newCardCVC}
+			bind:saveCard
+			showSaveCard={canSaveCards}
+			onfieldblur={handleFieldBlur}
+			onfieldinput={handleFieldInput}
+		/>
+		{#if cardError}
+			<p class="mt-1 text-xs font-semibold text-red-500">{cardError}</p>
+		{/if}
+	</div>
+{/if}

frontend/src/lib/components/payments/UserPaymentModal.svelte

@@ -1,6 +1,5 @@
 <script lang="ts">
 	import { onMount, onDestroy } from 'svelte';
-	import { SvelteDate } from 'svelte/reactivity';
 	import { toast } from 'svelte-sonner';
 	import { extractErrorMessage } from '$lib/utils/toast-safe';
 	import * as Dialog from '$lib/components/ui/dialog';
@@ -9,7 +8,7 @@
 	import { Checkbox } from '$lib/components/ui/checkbox';
 	import type { Booking } from '$lib/types/booking';
 	import type { UserSavedCard } from '$lib/types';
-	import CardInput from '$lib/components/payments/CardInput.svelte';
+	import CardSelection from '$lib/components/payments/CardSelection.svelte';
 	import PolicyPopover from '$lib/components/ui/policyPopover.svelte';
 	import { authStore } from '$lib/stores/auth.svelte';
 	import { apiFetch } from '$lib/utils/api';
@@ -41,112 +40,25 @@
 	// Card selection state
 	let paymentMethods = $state<UserSavedCard[]>([]);
 	let paymentMethodsLoading = $state(false);
-	let selectedPaymentMethod = $state<string | null>(null);
-	let showNewCardForm = $state(false);
-	let showCardList = $state(false);
+	let selectedCardId = $state('');
+	let cardSelectionValid = $state(false);
 
 	let stamps = $state(0);
 	let useLoyalty = $state(false);
 
 	// Auto-select first saved card when methods load
 	$effect(() => {
-		if (paymentMethods.length > 0 && !selectedPaymentMethod && !showNewCardForm) {
+		if (paymentMethods.length > 0 && !selectedCardId) {
 			const defaultCard = paymentMethods.find((m) => m.is_default) ?? paymentMethods[0];
-			selectedPaymentMethod = defaultCard.id;
+			selectedCardId = defaultCard.id;
 		}
 	});
 
-	// New card form fields
+	// New card form fields (bound into CardSelection)
 	let newCardNumber = $state('');
 	let newCardExpiry = $state('');
 	let newCardCVC = $state('');
 	let saveCardForFuture = $state(false);
-	let cardNumberTouched = $state(false);
-	let cardExpiryTouched = $state(false);
-	let cardCVCTouched = $state(false);
-
-	function parseExpiryParts(value: string): { month: number; year: number } | null {
-		if (!/^\d{2}\/\d{2}$/.test(value)) return null;
-		const [monthStr, yearStr] = value.split('/');
-		const month = parseInt(monthStr, 10);
-		const year = 2000 + parseInt(yearStr, 10);
-		if (month < 1 || month > 12) return null;
-		return { month, year };
-	}
-
-	const expiryParts = $derived(parseExpiryParts(newCardExpiry));
-
-	const isExpiryInPast = $derived(
-		expiryParts !== null &&
-			(() => {
-				const expiryYearMonth = expiryParts.year * 12 + expiryParts.month;
-				const now = new SvelteDate();
-				const currentYearMonth = now.getFullYear() * 12 + now.getMonth() + 1;
-				return expiryYearMonth < currentYearMonth;
-			})()
-	);
-
-	const hasInvalidMonth = $derived(/^\d{2}\/\d{2}$/.test(newCardExpiry) && expiryParts === null);
-
-	function isValidLuhn(cardNumber: string): boolean {
-		const s = cardNumber.replace(/\D/g, '');
-		let sum = 0;
-		let alternate = false;
-		for (let i = s.length - 1; i >= 0; i--) {
-			let n = parseInt(s[i], 10);
-			if (alternate) {
-				n *= 2;
-				if (n > 9) n -= 9;
-			}
-			sum += n;
-			alternate = !alternate;
-		}
-		return sum % 10 === 0 && s.length >= 13 && s.length <= 19;
-	}
-
-	function handleFieldBlur(field: string) {
-		if (field === 'cardNumber') cardNumberTouched = true;
-		else if (field === 'cardExpiry') cardExpiryTouched = true;
-		else if (field === 'cardCVC') cardCVCTouched = true;
-	}
-
-	function handleFieldInput(field: string) {
-		if (field === 'cardNumber') cardNumberTouched = false;
-		else if (field === 'cardExpiry') cardExpiryTouched = false;
-		else if (field === 'cardCVC') cardCVCTouched = false;
-	}
-
-	const cardFormValid = $derived(
-		isValidLuhn(newCardNumber) && expiryParts !== null && newCardCVC.length >= 3 && !isExpiryInPast
-	);
-
-	const cardSelected = $derived(
-		(selectedPaymentMethod !== null && paymentMethods.length > 0) ||
-			(showNewCardForm && cardFormValid) ||
-			(paymentMethods.length === 0 && cardFormValid)
-	);
-
-	const cardValidationError = $derived(
-		!cardSelected
-			? selectedPaymentMethod === null && paymentMethods.length > 0 && !showNewCardForm
-				? 'Please select a card'
-				: cardNumberTouched && !isValidLuhn(newCardNumber) && newCardNumber.length > 0
-					? 'Invalid card number'
-					: cardExpiryTouched && hasInvalidMonth
-						? 'Invalid expiry month'
-						: cardExpiryTouched && isExpiryInPast
-							? 'Expiry date in the past'
-							: cardExpiryTouched && !/^\d{2}\/\d{2}$/.test(newCardExpiry) && newCardExpiry.length > 0
-								? 'Enter expiry as MM/YY'
-								: cardCVCTouched && newCardCVC.length < 3 && newCardCVC.length > 0
-									? 'Enter your CVC number'
-									: isValidLuhn(newCardNumber) && /^\d{2}\/\d{2}$/.test(newCardExpiry) && newCardCVC.length >= 3
-										? null
-										: newCardNumber.length === 0 && newCardExpiry.length === 0 && newCardCVC.length === 0
-											? null
-											: 'Please complete all card fields'
-			: null
-	);
 
 	// Partial payment amount (in pounds, user enters)
 	let partialAmount = $state<string>('');
@@ -254,7 +166,7 @@
 
 	const payButtonDisabled = $derived(
 		status === 'processing' ||
-			!cardSelected ||
+			!cardSelectionValid ||
 			(paymentType === 'partial' && !partialAmountValid) ||
 			(booking.status === 'pending_release' && (lockTimer <= 0 || !lockAcquired))
 	);
@@ -383,10 +295,6 @@
 		}
 	}
 
-	function formatCardExpiry(month: number, year: number): string {
-		return `${String(month).padStart(2, '0')}/${year.toString().slice(-2)}`;
-	}
-
 	function sanitizeAmountInput(value: string): string {
 		// Remove all non-numeric chars except .
 		const cleaned = value.replace(/[^0-9.]/g, '');
@@ -442,8 +350,8 @@
 		let newCardToken: string | undefined;
 		let saveCard = false;
 
-		if (selectedPaymentMethod) {
-			cardId = selectedPaymentMethod;
+		if (selectedCardId) {
+			cardId = selectedCardId;
 		} else if (newCardNumber) {
 			newCardToken = newCardNumber;
 			saveCard = saveCardForFuture;
@@ -757,119 +665,18 @@
 				{#if status === 'idle' && authStore.isAuthenticated}
 					{#if paymentMethodsLoading}
 						<div class="py-2 text-center text-sm text-gray-500">Loading payment methods...</div>
-					{:else if paymentMethods.length > 0 && !showNewCardForm}
-						<!-- Saved card selected -->
-						<div class="space-y-3">
-							{#if selectedPaymentMethod}
-								{#each paymentMethods as method (method.id)}
-									{#if method.id === selectedPaymentMethod}
-										<div
-											class="flex items-center justify-between rounded-lg border border-input bg-fuchsia-100 p-3"
-										>
-											<div class="flex items-center gap-3">
-												<div
-													class="flex h-10 min-w-14 items-center justify-center rounded bg-gray-100 px-2 text-xs font-medium"
-												>
-													{method.brand}
-												</div>
-												<div class="text-sm">
-													<span class="font-mono">**** {method.last_4}</span>
-													<span class="ml-2 text-gray-500">
-														{formatCardExpiry(method.exp_month, method.exp_year)}
-													</span>
-												</div>
-											</div>
-											<span class="text-xs font-medium text-foreground">Selected</span>
-										</div>
-									{/if}
-								{/each}
-							{/if}
-							{#if canSaveCards}
-								<Button
-									variant="ghost"
-									size="sm"
-									class="text-sm text-gray-600"
-									onclick={() => (showCardList = !showCardList)}
-								>
-									{showCardList ? 'Hide other cards' : 'Use a different card'}
-								</Button>
-							{/if}
-
-							{#if showCardList}
-								<div class="space-y-2">
-									{#if canSaveCards}
-										<button
-											type="button"
-											class="flex w-full items-center justify-between rounded-lg border p-3 transition-colors hover:border-gray-300"
-											onclick={() => {
-												showNewCardForm = true;
-												showCardList = false;
-												selectedPaymentMethod = null;
-											}}
-										>
-											<div class="text-sm font-medium text-gray-700">Enter card details</div>
-											<svg
-												class="h-4 w-4 text-gray-400"
-												viewBox="0 0 24 24"
-												fill="none"
-												stroke="currentColor"
-												stroke-width="2"
-											>
-												<path d="M9 18l6-6-6-6" />
-											</svg>
-										</button>
-									{/if}
-									{#each paymentMethods as method (method.id)}
-										<button
-											type="button"
-											class="flex w-full items-center justify-between rounded-lg border p-3 {selectedPaymentMethod ===
-											method.id
-												? 'border-input bg-fuchsia-100'
-												: 'border-input hover:bg-fuchsia-50'}"
-											onclick={() => {
-												selectedPaymentMethod = method.id;
-												showNewCardForm = false;
-												showCardList = false;
-											}}
-										>
-											<div class="flex items-center gap-3">
-												<div
-													class="flex h-10 min-w-14 items-center justify-center rounded bg-gray-100 px-2 text-xs font-medium"
-												>
-													{method.brand}
-												</div>
-												<div class="text-sm">
-													<span class="font-mono">**** {method.last_4}</span>
-													<span class="ml-2 text-gray-500">
-														{formatCardExpiry(method.exp_month, method.exp_year)}
-													</span>
-												</div>
-											</div>
-											{#if selectedPaymentMethod === method.id}
-												<span class="text-xs font-medium text-foreground">Selected</span>
-											{/if}
-										</button>
-									{/each}
-								</div>
-							{/if}
-						</div>
 					{:else}
-						<CardInput
-							bind:cardNumber={newCardNumber}
-							bind:cardExpiry={newCardExpiry}
-							bind:cardCVC={newCardCVC}
+						<CardSelection
+							cards={paymentMethods}
+							{canSaveCards}
+							bind:selectedCardId
+							bind:newCardNumber
+							bind:newCardExpiry
+							bind:newCardCVC
 							bind:saveCard={saveCardForFuture}
-							showSaveCard={canSaveCards}
-							disabled={false}
-							onfieldblur={handleFieldBlur}
-							onfieldinput={handleFieldInput}
+							onValidityChange={(v) => (cardSelectionValid = v)}
 						/>
 					{/if}
-
-					<!-- Card validation error shown inline near card input -->
-					{#if cardValidationError}
-						<p class="text-sm text-red-600">{cardValidationError}</p>
-					{/if}
 				{/if}
 
 				{#if depositPolicyWarning}

frontend/src/routes/account/+page.svelte

@@ -172,6 +172,7 @@ import CardBrandIcon from '$lib/components/payments/CardBrandIcon.svelte';
 	let buyRecipientType = $state<'self' | 'friend'>('self');
 	let buyRecipientEmail = $state('');
 	let buySelectedCard = $state('');
+	let buyShowNewCard = $state(false);
 	let buyNewCardNumber = $state('');
 	let buyNewCardExpiry = $state('');
 	let buyNewCardCVC = $state('');
@@ -180,7 +181,10 @@ import CardBrandIcon from '$lib/components/payments/CardBrandIcon.svelte';
 	let purchaseResultCode = $state<string | null>(null);
 
 	$effect(() => {
-		if (savedCardsStore.cards.length > 0 && !buySelectedCard) {
+		// Auto-select the default saved card only once, when cards first load.
+		// Do NOT re-select when the user explicitly chooses "Use a new card"
+		// (buySelectedCard === ''), otherwise the click is immediately overridden.
+		if (savedCardsStore.cards.length > 0 && !buySelectedCard && !buyShowNewCard) {
 			const defaultCard =
 				savedCardsStore.cards.find((c) => c.is_default) || savedCardsStore.cards[0];
 			buySelectedCard = defaultCard.id;
@@ -359,6 +363,9 @@ import CardBrandIcon from '$lib/components/payments/CardBrandIcon.svelte';
 				await fetchGiftCardBalance();
 				if (buySelectedCard === '') {
 					await savedCardsStore.fetch();
+					// If the new card was saved, return to saved-card selection so the
+					// auto-select effect picks a default for the next purchase.
+					buyShowNewCard = false;
 				}
 			} else {
 				const errText = await res.text();
@@ -769,7 +776,9 @@ import CardBrandIcon from '$lib/components/payments/CardBrandIcon.svelte';
 				await fetchUserData();
 			} else {
 				const text = await response.text();
-				toast.error(sanitizeText(extractErrorMessage(text)) || 'Failed to update phone number', { id: loadingToast });
+				toast.error(sanitizeText(extractErrorMessage(text)) || 'Failed to update phone number', {
+					id: loadingToast
+				});
 			}
 		} catch (err) {
 			console.error('Error updating phone:', err);
@@ -874,7 +883,9 @@ import CardBrandIcon from '$lib/components/payments/CardBrandIcon.svelte';
 				await fetchUserData();
 			} else {
 				const text = await response.text();
-				toast.error(sanitizeText(extractErrorMessage(text)) || 'Failed to update name', { id: loadingToast });
+				toast.error(sanitizeText(extractErrorMessage(text)) || 'Failed to update name', {
+					id: loadingToast
+				});
 			}
 		} catch (err) {
 			console.error('Error updating name:', err);
@@ -1160,7 +1171,9 @@ import CardBrandIcon from '$lib/components/payments/CardBrandIcon.svelte';
 				passwordData = { current: '', new: '', confirm: '' };
 			} else {
 				const text = await response.text();
-				toast.error(sanitizeText(extractErrorMessage(text)) || 'Failed to change password', { id: loadingToast });
+				toast.error(sanitizeText(extractErrorMessage(text)) || 'Failed to change password', {
+					id: loadingToast
+				});
 			}
 		} catch (err) {
 			console.error('Error changing password:', err);
@@ -1206,7 +1219,9 @@ import CardBrandIcon from '$lib/components/payments/CardBrandIcon.svelte';
 				goto('/');
 			} else {
 				const text = await response.text();
-				toast.error(sanitizeText(extractErrorMessage(text)) || 'Failed to delete account', { id: loadingToast });
+				toast.error(sanitizeText(extractErrorMessage(text)) || 'Failed to delete account', {
+					id: loadingToast
+				});
 			}
 		} catch (err) {
 			console.error('Error deleting account:', err);
@@ -2388,6 +2403,7 @@ import CardBrandIcon from '$lib/components/payments/CardBrandIcon.svelte';
 														: 'border-gray-200 hover:bg-gray-50'}"
 													onclick={() => {
 														buySelectedCard = card.id;
+														buyShowNewCard = false;
 													}}
 												>
 													<div class="flex items-center gap-3">
@@ -2412,6 +2428,7 @@ import CardBrandIcon from '$lib/components/payments/CardBrandIcon.svelte';
 													: 'border-gray-200 hover:bg-gray-50'}"
 												onclick={() => {
 													buySelectedCard = '';
+													buyShowNewCard = true;
 												}}
 											>
 												<div class="flex items-center gap-3">