import { NextResponse } from "next/server";
import { stripeClient } from "../../../../lib/stripeClient";

export const runtime = "nodejs";

function logEvent(event: any) {
  const relatedId = event?.related_object?.id;
  const objectId = relatedId || event?.data?.object?.id;
  console.log(
    `[webhook] type=${event?.type} id=${event?.id} object_id=${objectId || "n/a"} livemode=${event?.livemode}`
  );
}

export async function POST(req: Request) {
  const webhookSecret = process.env.STRIPE_BILLING_WEBHOOK_SECRET;
  if (!webhookSecret) {
    return NextResponse.json(
      { error: "Missing STRIPE_BILLING_WEBHOOK_SECRET." },
      { status: 500 }
    );
  }

  const signature = req.headers.get("stripe-signature");
  if (!signature) {
    return NextResponse.json({ error: "Missing Stripe signature." }, { status: 400 });
  }

  const rawBody = Buffer.from(await req.arrayBuffer());

  try {
    // Try snapshot payload parsing first (standard webhook flow).
    try {
      const event = stripeClient.webhooks.constructEvent(
        rawBody,
        signature,
        webhookSecret
      );
      logEvent(event);

      if ((event as any).type === "v1.billing.meter.error_report_triggered") {
        // Log only per requirements.
      }

      return NextResponse.json({ received: true });
    } catch {
      // Fall through to thin payload handling.
    }

    const clientAny = stripeClient as any;
    if (typeof clientAny.parseThinEvent !== "function") {
      return NextResponse.json(
        { error: "Stripe SDK does not support parseThinEvent." },
        { status: 500 }
      );
    }

    const thinEvent = clientAny.parseThinEvent(rawBody, signature, webhookSecret);
    const fullEvent = await stripeClient.events.retrieve(thinEvent.id);
    logEvent(fullEvent);

    if ((fullEvent as any).type === "v1.billing.meter.error_report_triggered") {
      // Log only per requirements.
    }

    return NextResponse.json({ received: true });
  } catch (err: any) {
    return NextResponse.json(
      { error: err?.message || "Webhook handler failed." },
      { status: 400 }
    );
  }
}