import { NextResponse } from "next/server";
import { getPayload } from "payload";
import config from "@payload-config";

export const dynamic = "force-dynamic";

type Args = { params: Promise<{ slug: string }> };

export async function POST(request: Request, { params }: Args) {
  const { slug } = await params;

  let body: { name?: unknown; email?: unknown };
  try {
    body = await request.json();
  } catch {
    return NextResponse.json({ error: "Ungültige Anfrage." }, { status: 400 });
  }

  const name = typeof body.name === "string" ? body.name.trim() : "";
  const email = typeof body.email === "string" ? body.email.trim() : "";
  if (!name || !email || !email.includes("@")) {
    return NextResponse.json({ error: "Bitte gib deinen Namen und eine gültige E-Mail-Adresse an." }, { status: 400 });
  }

  try {
    const payload = await getPayload({ config });

    const { docs } = await payload.find({
      collection: "events",
      where: { slug: { equals: slug } },
      limit: 1,
    });
    const event = docs[0];
    if (!event) {
      return NextResponse.json({ error: "Dieser Termin wurde nicht gefunden." }, { status: 404 });
    }

    const { docs: existingForEmail } = await payload.find({
      collection: "event-registrations",
      where: {
        and: [
          { event: { equals: event.id } },
          { email: { equals: email } },
          { status: { equals: "registered" } },
        ],
      },
      limit: 1,
    });
    if (existingForEmail[0]) {
      return NextResponse.json({ ok: true, alreadyRegistered: true });
    }

    if (event.maxParticipants) {
      const { totalDocs } = await payload.count({
        collection: "event-registrations",
        where: { and: [{ event: { equals: event.id } }, { status: { equals: "registered" } }] },
      });
      if (totalDocs >= event.maxParticipants) {
        return NextResponse.json({ error: "Dieser Termin ist bereits ausgebucht." }, { status: 409 });
      }
    }

    await payload.create({
      collection: "event-registrations",
      data: { event: event.id, name, email, status: "registered" },
    });

    return NextResponse.json({ ok: true });
  } catch (error) {
    console.error("event registration failed", error);
    return NextResponse.json({ error: "Die Anmeldung ist gerade nicht möglich. Bitte versuche es später erneut." }, { status: 500 });
  }
}