/** Call-time switches for consult preparation. Read on each request, not at import. */

const warned = new Set<string>();

function warnOnce(name: string, raw: string): void {
  if (warned.has(name)) return;
  warned.add(name);
  console.warn(`[consult-prep] ${name} 的值无法识别，按默认处理`);
  void raw;
}

function readRaw(env: Readonly<Record<string, string | undefined>>, name: string): string | undefined {
  const raw = env[name];
  if (raw === undefined) return undefined;
  const trimmed = raw.trim();
  return trimmed ? trimmed : undefined;
}

export function consultPrepParallelEnabled(
  env: Readonly<Record<string, string | undefined>> = process.env,
): boolean {
  const raw = readRaw(env, "CONSULT_PREP_PARALLEL");
  if (raw === undefined) return false;
  const value = raw.toLowerCase();
  if (value === "on") return true;
  if (value === "off") return false;
  warnOnce("CONSULT_PREP_PARALLEL", raw);
  return false;
}

/** 0 closes the cache. Anything outside 0–15000 stays on the default, which is off. */
export function modelVersionCacheTtlMs(
  env: Readonly<Record<string, string | undefined>> = process.env,
): number {
  const raw = readRaw(env, "MODEL_VERSION_CACHE_TTL_MS");
  if (raw === undefined) return 0;
  if (!/^\d+$/.test(raw)) {
    warnOnce("MODEL_VERSION_CACHE_TTL_MS", raw);
    return 0;
  }
  const parsed = Number(raw);
  if (parsed > 15_000) {
    warnOnce("MODEL_VERSION_CACHE_TTL_MS", raw);
    return 0;
  }
  return parsed;
}

/** 1 is today's serial loop. 2 starts the capped domains together. */
export function consultDomainConcurrency(
  env: Readonly<Record<string, string | undefined>> = process.env,
): 1 | 2 {
  const raw = readRaw(env, "CONSULT_DOMAIN_CONCURRENCY");
  if (raw === undefined || raw === "1") return 1;
  if (raw === "2") return 2;
  warnOnce("CONSULT_DOMAIN_CONCURRENCY", raw);
  return 1;
}

export function resetConsultPrepFlagWarningsForTests(): void {
  warned.clear();
}