Add Stripe subscription integration with pricing plans

src/lib/stripe.ts

@@ -0,0 +1,76 @@
+import Stripe from 'stripe';
+
+if (!process.env.STRIPE_SECRET_KEY) {
+  throw new Error('STRIPE_SECRET_KEY is not set');
+}
+
+export const stripe = new Stripe(process.env.STRIPE_SECRET_KEY, {
+  apiVersion: '2024-11-20.acacia',
+  typescript: true,
+});
+
+export const STRIPE_PLANS = {
+  FREE: {
+    name: 'Free / Starter',
+    price: 0,
+    currency: 'EUR',
+    interval: 'month',
+    features: [
+      '3 dynamische QR-Codes',
+      'Basis-Tracking (Scans + Standort)',
+      'Einfache Designs',
+      'Unbegrenzte statische QR-Codes',
+    ],
+    limits: {
+      dynamicQRCodes: 3,
+      staticQRCodes: -1, // unlimited
+      teamMembers: 1,
+    },
+    priceId: null, // No Stripe price for free plan
+  },
+  PRO: {
+    name: 'Pro',
+    price: 9,
+    priceYearly: 90,
+    currency: 'EUR',
+    interval: 'month',
+    features: [
+      '50 QR-Codes',
+      'Branding (Logo, Farben)',
+      'Detaillierte Analytics (Datum, Gerät, Stadt)',
+      'CSV-Export',
+      'Passwortschutz',
+    ],
+    limits: {
+      dynamicQRCodes: 50,
+      staticQRCodes: -1,
+      teamMembers: 1,
+    },
+    priceId: process.env.STRIPE_PRICE_ID_PRO_MONTHLY,
+    priceIdYearly: process.env.STRIPE_PRICE_ID_PRO_YEARLY,
+  },
+  BUSINESS: {
+    name: 'Business',
+    price: 29,
+    priceYearly: 290,
+    currency: 'EUR',
+    interval: 'month',
+    features: [
+      '500 QR-Codes',
+      'Team-Zugänge (bis 3 User)',
+      'API-Zugang',
+      'Benutzerdefinierte Domains',
+      'White-Label',
+      'Prioritäts-Support',
+    ],
+    limits: {
+      dynamicQRCodes: 500,
+      staticQRCodes: -1,
+      teamMembers: 3,
+    },
+    priceId: process.env.STRIPE_PRICE_ID_BUSINESS_MONTHLY,
+    priceIdYearly: process.env.STRIPE_PRICE_ID_BUSINESS_YEARLY,
+  },
+} as const;
+
+export type PlanType = keyof typeof STRIPE_PLANS;