import { NextResponse } from "next/server";
import { workerEndpointEnabled } from "yt-dlp-transcript-common/lib/workerToken";
import { testRouteDenied } from "../_guard";

export const dynamic = "force-dynamic";

// E2E test harness only. Unsets and restores `WORKER_TOKEN` inside the running
// server.
//
// WHY A ROUTE AND NOT A SPEC FIXTURE. The 503 branch is the one that decides
// whether an instance is an open transcription server — unset means OFF, you
// opt in — and no spec could observe it: the test server boots with
// WORKER_TOKEN=test-worker-token (editor/package.json, dev:test) and ONE server
// serves the whole suite, so the only way to see the endpoint disabled is to
// turn it off in the process that is answering. A suite cannot restart the dev
// server mid-run, which is the same reason /api/test/resume-lane exists.
//
// IT WORKS BECAUSE `getWorkerToken()` READS process.env PER CALL, never at
// import (common/lib/workerToken.test.ts pins that). A module-level cache would
// make this route a silent no-op and the spec below would pass by proving
// nothing.
//
// ⚠️ THE SPEC MUST RESTORE IN A `finally`. The variable is process-wide and the
// server outlives the spec, so a run that unsets it and throws leaves every
// later /api/ops and /api/worker spec answering 503 — a whole suite red from
// one failure. `?set=` with no value is the restore, and it is idempotent.
//
// GUARDED BY `E2E_TEST_ROUTES`, and it is the route that made the guard
// necessary: an unauthenticated GET that SETS a credential is a CSRF-able
// token grant, and "the editor is a localhost admin tool" does not help — the
// operator's browser is inside the loopback. See _guard.ts.
export async function GET(req: Request) {
  // FIRST LINE, BEFORE THE QUERY IS EVEN PARSED. This route sets a credential;
  // off a harness-started server it does not exist. See _guard.ts.
  const denied = testRouteDenied();
  if (denied) return denied;
  const url = new URL(req.url);
  // `?set=<token>` restores (or changes) it; `?unset=1` removes it entirely.
  // Exactly one of the two, so a typo cannot silently do nothing.
  const set = url.searchParams.get("set");
  const unset = url.searchParams.get("unset");
  if ((set === null) === (unset === null)) {
    return NextResponse.json(
      { ok: false, error: "pass exactly one of ?set=<token> or ?unset=1" },
      { status: 400 },
    );
  }
  const before = workerEndpointEnabled();
  if (unset !== null) delete process.env.WORKER_TOKEN;
  else process.env.WORKER_TOKEN = set as string;
  return NextResponse.json({
    ok: true,
    was: before,
    // Never the token itself: this response goes into a test log.
    enabled: workerEndpointEnabled(),
  });
}