import type { Server } from 'node:http';

const DEFAULT_KEEP_ALIVE_TIMEOUT_MS = 120_000;
const DEFAULT_HEADERS_TIMEOUT_MS = 125_000;

export function configureApiHttpServerTimeouts(
  server: Pick<Server, 'keepAliveTimeout' | 'headersTimeout'>,
  env: NodeJS.ProcessEnv,
) {
  const keepAliveTimeoutMs = positiveInteger(env.API_HTTP_KEEP_ALIVE_TIMEOUT_MS, DEFAULT_KEEP_ALIVE_TIMEOUT_MS);
  const configuredHeadersTimeoutMs = positiveInteger(env.API_HTTP_HEADERS_TIMEOUT_MS, DEFAULT_HEADERS_TIMEOUT_MS);
  const headersTimeoutMs = Math.max(configuredHeadersTimeoutMs, keepAliveTimeoutMs + 1_000);
  server.keepAliveTimeout = keepAliveTimeoutMs;
  server.headersTimeout = headersTimeoutMs;
  return { keepAliveTimeoutMs, headersTimeoutMs };
}

function positiveInteger(value: string | undefined, fallback: number) {
  const parsed = Number(value);
  return Number.isInteger(parsed) && parsed > 0 ? parsed : fallback;
}