import { NextResponse } from "next/server";
import { opsAuth, opsFail } from "../../_lib";
import { readJob } from "../../_jobs";

export const dynamic = "force-dynamic";

// GET /api/ops/job/<id>[?tail=<lines>]
//
// ONE JOB'S STATE, behind the token: its kind, channel, status, times, exit
// code and replay flag — from the registry while it is live, from its
// `.meta.json` sidecar after — and, while it is queued or running, WHERE it
// waits: `queue: {key, position, queued, head}` (0 = running at the head; the
// head is the job holding the queue when it is not this one). `?tail=N` adds the
// log's last N lines (at most 500), read from the end of the file.
//
// What `pnpm ops --wait` asks when the log endpoint stops answering, in place of
// the `/api/jobs/active` view: that is a UI poll — ungated, a rewrite onto
// /api/view/activeJobs that builds the whole live payload (channel stats, the
// disk gate, every runner's status) to answer "is job X still there?". This
// reads one record and one sidecar, and it can say how the job ended after the
// registry forgot it, which the active list never could.
//
// An id neither the registry nor `.jobs/` knows is a 404 `{ ok: false }`.
const MAX_TAIL = 500;

export async function GET(
  request: Request,
  { params }: { params: Promise<{ id: string }> },
) {
  const denied = opsAuth(request);
  if (denied) return denied;
  const { id } = await params;
  // The log route's own id rule: the id names a file under .jobs/.
  if (!/^[A-Za-z0-9_-]+$/.test(id)) return opsFail(`"${id}" is not a job id`);
  const url = new URL(request.url);
  const unknown = [...url.searchParams.keys()].filter((k) => k !== "tail");
  if (unknown.length) {
    return opsFail(`unknown query key(s): ${unknown.join(", ")} — accepted: tail`);
  }
  const rawTail = url.searchParams.get("tail");
  let tail = 0;
  if (rawTail !== null) {
    tail = Number(rawTail);
    if (!Number.isInteger(tail) || tail <= 0) {
      return opsFail('"tail" must be a whole number of lines above zero');
    }
    tail = Math.min(tail, MAX_TAIL);
  }
  const found = await readJob(id, tail);
  if (!found) return opsFail(`no job "${id}"`, 404);
  return NextResponse.json({ ok: true, ...found });
}