// POST /api/seed/turn
//
// Per-turn handler for the live seed interview. Stateless — client passes
// the running thread + draft + user text; we return the next assistant turn
// + an updated draft + a `ready` flag.

import { NextResponse } from "next/server";
import { interviewStep, type InterviewTurn, type SeedDraft } from "../../../../lib/llm/seedInterview";

export async function POST(req: Request) {
  let body: { history?: InterviewTurn[]; userText?: string; draft?: SeedDraft };
  try {
    body = await req.json();
  } catch {
    return NextResponse.json({ error: "invalid json body" }, { status: 400 });
  }

  const history = Array.isArray(body.history) ? body.history : [];
  const draft: SeedDraft = body.draft ?? {
    title: "",
    problem: "",
    targetUser: "",
    desiredOutcome: "",
  };
  const userText = body.userText ?? "";

  try {
    const result = await interviewStep({ history, userText, draft });
    return NextResponse.json({
      assistant: { text: result.text },
      draft: result.draft,
      confidence: result.confidence,
      ready: result.ready,
      meta: {
        provider: result.provider,
        model: result.model,
        inputTokens: result.inputTokens,
        outputTokens: result.outputTokens,
      },
    });
  } catch (err) {
    return NextResponse.json({ error: (err as Error).message }, { status: 500 });
  }
}