/**
 * Health check endpoint for docs-chat API.
 */
import type { VercelRequest, VercelResponse } from "@vercel/node";
import { DocsStore } from "../rag/store-upstash.js";

const corsHeaders: Record<string, string> = {
  "Access-Control-Allow-Origin": "*",
  "Access-Control-Allow-Methods": "GET, OPTIONS",
  "Access-Control-Allow-Headers": "Content-Type",
};

export default async function handler(req: VercelRequest, res: VercelResponse) {
  // Handle CORS preflight
  if (req.method === "OPTIONS") {
    Object.entries(corsHeaders).forEach(([key, value]) => {
      res.setHeader(key, value);
    });
    res.status(204).end();
    return;
  }

  if (req.method !== "GET") {
    res.status(405).json({ error: "Method not allowed" });
    return;
  }

  try {
    const store = new DocsStore();
    const count = await store.count();

    Object.entries(corsHeaders).forEach(([key, value]) => {
      res.setHeader(key, value);
    });
    res.status(200).json({ ok: true, chunks: count, mode: "upstash-vector" });
  } catch (err) {
    console.error("Health check error:", err);
    res.status(500).json({ ok: false, error: "Failed to connect to vector store" });
  }
}