import type { NextRequest } from "next/server";
import { paymentWebhookInputSchema } from "@salixcommerce/core";
import { errorResponse } from "@/server/commerce/http";
import { paymentResultResponse } from "@/server/payments/http";
import { paymentRuntime } from "@/server/payments/payments";

export const runtime = "nodejs";

const MAX_WEBHOOK_BYTES = 1_048_576;

export async function POST(request: NextRequest) {
  if (paymentRuntime.provider?.key !== "stripe") {
    return errorResponse("PAYMENTS_UNAVAILABLE", "Stripe payments are not configured.", 503);
  }

  const declaredLength = readContentLength(request.headers.get("content-length"));
  if (declaredLength !== null && declaredLength > MAX_WEBHOOK_BYTES) {
    return errorResponse("INVALID_REQUEST", "Stripe webhook body is too large.", 400);
  }
  const signature = request.headers.get("stripe-signature");
  if (signature === null) {
    return errorResponse("INVALID_REQUEST", "Stripe webhook signature is required.", 400);
  }

  const rawBody = await request.text();
  const parsed = paymentWebhookInputSchema.safeParse({ rawBody, signature });
  if (!parsed.success) {
    return errorResponse("INVALID_REQUEST", "Invalid Stripe webhook request.", 400);
  }
  return paymentResultResponse(await paymentRuntime.service.processWebhook(parsed.data));
}

function readContentLength(value: string | null): number | null {
  if (value === null) return null;
  if (!/^[0-9]+$/u.test(value)) return Number.POSITIVE_INFINITY;
  const length = Number(value);
  return Number.isSafeInteger(length) ? length : Number.POSITIVE_INFINITY;
}