Payments with Stripe

export interface Plan {
  id: string;
  name: string;
  description: string;
  monthlyPrice: number | null;
  yearlyPrice: number | null;
  stripePriceIds: { monthly: string | null; yearly: string | null };
  features: string[];
  isPopular: boolean;
  buttonText: string;
  isContactUs?: boolean;
  isFree?: boolean;
}

export const plans: Plan[] = [
  // ...free plan omitted...
  {
    id: "pro",
    name: "Pro",
    description: "Ideal for professionals and small teams",
    monthlyPrice: 12,
    yearlyPrice: 10, // $120/year = $10/month
    stripePriceIds: {
      monthly: process.env.NEXT_PUBLIC_STRIPE_PRICE_ID_PRO_MONTHLY || null,
      yearly: process.env.NEXT_PUBLIC_STRIPE_PRICE_ID_PRO_YEARLY || null,
    },
    features: [
      "Custom domain",
      "SEO-optimizations",
      "Auto-generated API docs",
      "Built-in components library",
      "E-commerce integration",
      "User authentication system",
      "Multi-language support",
      "Real-time collaboration tools",
    ],
    isPopular: true,
    buttonText: "Upgrade to Pro",
  },
  // ...enterprise plan omitted...
];

export function getPlanById(planId: string): Plan | undefined {
  return plans.find((plan) => plan.id === planId);
}

export function getPlanByPriceId(priceId: string): Plan | undefined {
  return plans.find(
    (plan) =>
      plan.stripePriceIds.monthly === priceId ||
      plan.stripePriceIds.yearly === priceId
  );
}

export function getBillingCycle(priceId: string): "month" | "year" {
  return plans.some((plan) => plan.stripePriceIds.yearly === priceId)
    ? "year"
    : "month";
}

export function formatPrice(amount: number): string {
  return new Intl.NumberFormat("en-US", {
    style: "currency",
    currency: "USD",
    minimumFractionDigits: 0,
  }).format(amount);
}

const handleSubscribe = async (priceId: string) => {
  // Create form and submit to checkout endpoint
  const form = document.createElement('form');
  form.method = 'POST';
  form.action = '/api/checkout_sessions';
  
  const input = document.createElement('input');
  input.type = 'hidden';
  input.name = 'price_id';
  input.value = priceId;
  
  form.appendChild(input);
  document.body.appendChild(form);
  form.submit(); // Redirects to Stripe Checkout
};

const handleManageSubscription = async () => {
  const response = await fetch('/api/customer_portal', {
    method: 'POST',
    credentials: 'include',
  });
  
  const { url } = await response.json();
  window.location.href = url; // Redirects to Stripe portal
};

export async function POST(request: Request) {
  // 1. Verify webhook signature
  const signature = request.headers.get("stripe-signature");
  const event = stripe.webhooks.constructEvent(
    body, 
    signature, 
    process.env.STRIPE_WEBHOOK_SECRET
  );
  
  // 2. Process event based on type
  switch (event.type) {
    case "customer.subscription.created":
    case "customer.subscription.updated":
      // Update user_subscriptions table
      const subscription = event.data.object;
      await supabase.from("user_subscriptions").upsert({
        user_id: subscription.metadata.user_id,
        stripe_customer_id: subscription.customer,
        stripe_subscription_id: subscription.id,
        plan_name: getPlanByPriceId(subscription.items.data[0].price.id)?.name,
        status: subscription.status,
        billing_cycle: getBillingCycle(subscription.items.data[0].price.id),
        // ... more fields
      });
      break;
      
    case "invoice.payment_succeeded":
      // Record payment (requires fetching subscription for metadata)
      const invoice = event.data.object;
      const subscriptionId = invoice.subscription;
      const subscription = await stripe.subscriptions.retrieve(subscriptionId);
      const userId = subscription.metadata.user_id;

      await supabase.from("payment_history").insert({
        user_id: userId,
        stripe_subscription_id: subscriptionId,
        amount: invoice.amount_paid,
        currency: invoice.currency,
        status: "succeeded",
        invoice_url: invoice.hosted_invoice_url,
      });
      break;
  }
  
  return new Response(null, { status: 200 });
}

const session = await stripe.checkout.sessions.create({
  // ... other parameters
  subscription_data: {
    trial_period_days: 14,  // 14-day free trial
    metadata: { user_id: user.id },
  },
});

const session = await stripe.checkout.sessions.create({
  allow_promotion_codes: true,  // Customers can enter promo codes
// ...
});