import { applyVerdict, undoLastVerdict } from "@/lib/verdict";
import { addVocab } from "@/lib/vocab";
import { isMode, type VerdictBody } from "@/lib/types";

export const dynamic = "force-dynamic";

export async function POST(request: Request) {
  let body: VerdictBody & { undo?: boolean };
  try {
    body = (await request.json()) as VerdictBody & { undo?: boolean };
  } catch {
    return Response.json({ error: "bad json" }, { status: 400 });
  }

  // Undo takes no key: it puts back the LAST verdict, whatever it was. Anything
  // else would need the client to know which of several piles a verdict moved a
  // key between, which is precisely the knowledge the journal exists to hold.
  if (body?.undo) {
    const out = await undoLastVerdict();
    if (!out.ok) return Response.json({ error: out.error }, { status: 400 });
    return Response.json(out);
  }

  if (!body?.key || !isMode(body.mode) || !Number.isInteger(body.verdict)) {
    return Response.json({ error: "key, mode and verdict are required" }, { status: 400 });
  }
  // A custom word joins the vocabulary BEFORE the verdict lands, so it is
  // offered on the next clip even if the verdict write then fails.
  if (body.custom && body.word) await addVocab(body.word);
  try {
    return Response.json(await applyVerdict(body));
  } catch (err) {
    return Response.json({ error: String((err as Error)?.message ?? err) }, { status: 500 });
  }
}