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

export const dynamic = "force-dynamic";

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

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

  try {
    const payload = await getPayload({ config });
    const { user } = await payload.auth({ headers: request.headers });
    if (!user || user.collection !== "customers") {
      return NextResponse.json({ error: "Bitte melde dich an." }, { status: 401 });
    }
    if (!user.emailVerified) {
      return NextResponse.json({ error: "Bitte bestätige zuerst deine E-Mail-Adresse.", code: "EMAIL_NOT_VERIFIED" }, { status: 403 });
    }

    const booking = await payload.findByID({ collection: "booking-requests", id, depth: 0 }).catch(() => null);
    if (!booking || Number(booking.user) !== Number(user.id)) {
      return NextResponse.json({ error: "Buchung nicht gefunden." }, { status: 404 });
    }
    const alternative = booking.proposedAlternative;
    if (booking.status !== "pending" || !alternative?.date || !alternative.startTime || !alternative.endTime) {
      return NextResponse.json({ error: "Für diese Buchung liegt kein alternativer Termin vor." }, { status: 409 });
    }

    // The beforeChange hook on booking-requests re-checks for conflicts
    // (with an advisory lock) before allowing this to become "confirmed" —
    // the alternative slot may have been taken by someone else since it was
    // proposed.
    await payload.update({
      collection: "booking-requests",
      id,
      data: {
        status: "confirmed",
        date: alternative.date,
        startTime: alternative.startTime,
        endTime: alternative.endTime,
      },
    });

    return NextResponse.json({ ok: true });
  } catch (error) {
    if (error instanceof Error && "status" in error && (error as { status: number }).status === 409) {
      return NextResponse.json({ error: error.message }, { status: 409 });
    }
    console.error("accept-alternative failed", error);
    return NextResponse.json({ error: "Der Termin konnte nicht angenommen werden." }, { status: 500 });
  }
}