refactor progress

packages/api/src/stripe/StripeSubscriptionPeriod.tsx

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2026 Fluxer Contributors
+ *
+ * This file is part of Fluxer.
+ *
+ * Fluxer is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Fluxer is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with Fluxer. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import type Stripe from 'stripe';
+
+export function getPrimarySubscriptionItem(subscription: Stripe.Subscription): Stripe.SubscriptionItem | null {
+	const items = subscription.items?.data ?? [];
+	if (items.length === 0) {
+		return null;
+	}
+
+	const recurringItem = items.find((item) => Boolean(item.price?.recurring));
+	return recurringItem ?? items[0];
+}
+
+export function getSubscriptionItemPeriodEndUnix(item: Stripe.SubscriptionItem | null): number | null {
+	return item?.current_period_end ?? null;
+}
+
+export function getSubscriptionItemPeriodEnd(item: Stripe.SubscriptionItem | null): Date | null {
+	const periodEnd = getSubscriptionItemPeriodEndUnix(item);
+	return periodEnd == null ? null : new Date(periodEnd * 1000);
+}
+
+export function getSubscriptionCurrentPeriodEnd(subscription: Stripe.Subscription): Date | null {
+	const items = subscription.items?.data ?? [];
+	if (items.length === 0) {
+		return null;
+	}
+
+	let latestPeriodEnd: number | null = null;
+	for (const item of items) {
+		if (item.current_period_end == null) {
+			continue;
+		}
+		if (latestPeriodEnd == null || item.current_period_end > latestPeriodEnd) {
+			latestPeriodEnd = item.current_period_end;
+		}
+	}
+
+	return latestPeriodEnd == null ? null : new Date(latestPeriodEnd * 1000);
+}