/** Batched request logging into ClickHouse `api_requests` (never fatal, never awaited on the request path). */
import { chInsert } from "@dci/db/clickhouse";

interface Req { ts: string; route: string; status: number; duration_ms: number; cached: number }

const buffer: Req[] = [];
let timer: NodeJS.Timeout | null = null;
let disabled = process.env.DCI_API_CH_LOG === "0";
const FLUSH_MS = 5_000;
const MAX = 2_000;

export function recordRequest(route: string, status: number, durationMs: number, cached: boolean): void {
  if (disabled) return;
  if (buffer.length >= MAX) buffer.splice(0, buffer.length - MAX + 1);
  buffer.push({ ts: new Date().toISOString().replace("T", " ").slice(0, 19), route, status, duration_ms: Math.max(0, Math.round(durationMs)), cached: cached ? 1 : 0 });
  if (!timer) timer = setTimeout(() => { timer = null; void flushRequests(); }, FLUSH_MS);
}

export async function flushRequests(): Promise<void> {
  if (!buffer.length) return;
  const rows = buffer.splice(0, buffer.length);
  try {
    await chInsert("api_requests", rows as unknown as Record<string, unknown>[]);
  } catch {
    /* chInsert already swallows in optional mode; belt and braces */
  }
}

export function stopTelemetry(): void {
  if (timer) clearTimeout(timer);
  timer = null;
  disabled = true;
}