import { NextRequest, NextResponse } from "next/server";
import { getCurrentUser } from "@/lib/auth";
import { getTripById, updateTrip, deleteTrip } from "@/lib/queries";

export async function GET(req: NextRequest, { params }: { params: Promise<{ id: string }> }) {
  const user = await getCurrentUser(req);
  if (!user) return NextResponse.json({ error: "Forbidden" }, { status: 403 });
  const { id } = await params;
  const trip = await getTripById(Number(id), user.id);
  if (!trip) return NextResponse.json({ error: "Not found" }, { status: 404 });
  return NextResponse.json(trip);
}

export async function PATCH(req: NextRequest, { params }: { params: Promise<{ id: string }> }) {
  const user = await getCurrentUser(req);
  if (!user) return NextResponse.json({ error: "Forbidden" }, { status: 403 });
  const { id } = await params;
  const body = await req.json();
  const trip = await updateTrip(Number(id), user.id, body);
  if (!trip) return NextResponse.json({ error: "Not found" }, { status: 404 });
  return NextResponse.json(trip);
}

// Everything else about a trip is shared; delete is not. Both trip foreign keys
// are ON DELETE SET NULL, so this untags every transaction on the trip and drops
// the trip scope from its payments — including the hand-derived Europe-first
// allocation, which nothing recomputes. A participant gets a 403 that says so
// rather than a 404 that pretends the trip is not there.
export async function DELETE(req: NextRequest, { params }: { params: Promise<{ id: string }> }) {
  const user = await getCurrentUser(req);
  if (!user) return NextResponse.json({ error: "Forbidden" }, { status: 403 });
  const { id } = await params;
  const trip = await getTripById(Number(id), user.id);
  if (!trip) return NextResponse.json({ error: "Not found" }, { status: 404 });
  if (trip.owner_id !== user.id) {
    return NextResponse.json(
      { error: "Only the trip owner can delete a trip. Deleting it would untag every transaction on it and unscope its payments." },
      { status: 403 }
    );
  }
  await deleteTrip(Number(id), user.id);
  return new NextResponse(null, { status: 204 });
}