/**
 * Proxies to the worker's internal HTTP server (DCI_WORKER_URL, default http://127.0.0.1:8320; compose:
 * http://worker-maint:8320): GET /data-gaps and GET /trace/<documentId> (extraction debugger). 10 s timeout, 502 on failure.
 */
import type { FastifyInstance } from "fastify";
import { z } from "zod";
import { getEnv } from "../../env.js";
import { envelope, HttpError, parseQuery } from "../../lib/http.js";
import { strParam } from "../../lib/params.js";

async function workerGet(path: string): Promise<unknown> {
  const base = getEnv().workerUrl.replace(/\/+$/, "");
  const url = `${base}${path}`;
  let host = base;
  try { host = new URL(base).host; } catch { /* keep raw */ }
  try {
    const res = await fetch(url, { headers: { accept: "application/json" }, signal: AbortSignal.timeout(10_000) });
    const text = await res.text();
    let body: unknown = text;
    try { body = JSON.parse(text); } catch { /* keep text */ }
    if (!res.ok) throw new HttpError(res.status === 404 ? 404 : 502, `worker answered HTTP ${res.status}`, { worker: host, path, body });
    return body;
  } catch (e) {
    if (e instanceof HttpError) throw e;
    const msg = (e as Error).name === "TimeoutError" ? "timeout after 10 s" : (e as Error).message;
    throw new HttpError(502, `worker unreachable: ${msg}`, { worker: host, path });
  }
}

export async function proxyAdminRoutes(app: FastifyInstance): Promise<void> {
  app.get("/data-gaps", { schema: { summary: "Data gaps counters (proxied from the worker GET /data-gaps; 502 when the worker is unreachable)" } }, async () => envelope(await workerGet("/data-gaps"), { source: getEnv().workerUrl }));

  app.get("/documents/:id/trace", { schema: { summary: "Extraction debugger trace for a document (proxied from the worker GET /trace/<id>?live=1 re-fetches the page)" } }, async (req) => {
    const { id } = req.params as { id: string };
    const q = parseQuery(z.object({ live: strParam }), req.query);
    const live = q.live === "1" || q.live === "true" ? "1" : "";
    return envelope(await workerGet(`/trace/${encodeURIComponent(id)}${live ? "?live=1" : ""}`), { source: getEnv().workerUrl, live: live === "1" });
  });
}