import { api } from "./api";

declare global {
  interface Window { Razorpay?: any }
}

function loadScript(): Promise<boolean> {
  return new Promise((resolve) => {
    if (window.Razorpay) return resolve(true);
    const s = document.createElement("script");
    s.src = "https://checkout.razorpay.com/v1/checkout.js";
    s.onload = () => resolve(true);
    s.onerror = () => resolve(false);
    document.body.appendChild(s);
  });
}

/**
 * Start a plan upgrade/downgrade. Creates an order, opens Razorpay checkout
 * (or auto-confirms in mock mode), then verifies and activates the plan.
 * Returns true on success.
 */
export async function purchasePlan(
  planId: string,
  coupon?: string,
  onSuccess?: (invoiceNumber?: string) => void
): Promise<void> {
  const order = await api("/billing/create-order", {
    method: "POST",
    body: JSON.stringify({ plan_id: planId, coupon: coupon || undefined }),
  });

  // Free / fully-discounted plan — activated server-side already.
  if (order.free) { onSuccess?.(); return; }

  // Mock mode (no Razorpay keys): skip the modal, verify directly.
  if (order.mock) {
    const res = await api("/billing/verify", {
      method: "POST",
      body: JSON.stringify({
        razorpay_order_id: order.order_id,
        razorpay_payment_id: `pay_mock_${Date.now()}`,
        razorpay_signature: "mock",
        plan_id: order.plan_id,
      }),
    });
    onSuccess?.(res.invoice_number);
    return;
  }

  // Live mode — open Razorpay checkout.
  const ok = await loadScript();
  if (!ok) throw new Error("Failed to load Razorpay checkout");

  await new Promise<void>((resolve, reject) => {
    const rzp = new window.Razorpay({
      key: order.key_id,
      amount: order.amount * 100,
      currency: order.currency,
      name: "VerifyPack",
      description: `${order.plan_name} plan`,
      order_id: order.order_id,
      handler: async (resp: any) => {
        try {
          const res = await api("/billing/verify", {
            method: "POST",
            body: JSON.stringify({
              razorpay_order_id: resp.razorpay_order_id,
              razorpay_payment_id: resp.razorpay_payment_id,
              razorpay_signature: resp.razorpay_signature,
              plan_id: order.plan_id,
            }),
          });
          onSuccess?.(res.invoice_number);
          resolve();
        } catch (e) { reject(e); }
      },
      modal: { ondismiss: () => reject(new Error("Payment cancelled")) },
      theme: { color: "#2563eb" },
    });
    rzp.open();
  });
}