worldmonitor/server/_shared/constants.ts

export const CHROME_UA = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36';

export function clampInt(value: number | undefined, fallback: number, min: number, max: number): number {
  if (!Number.isFinite(value)) return fallback;
  return Math.max(min, Math.min(max, Math.floor(value as number)));
}

/**
 * Global Yahoo Finance request gate.
 * Ensures minimum spacing between ANY Yahoo requests across all handlers.
 * Multiple handlers calling Yahoo concurrently causes IP-level rate limiting (429).
 */
let yahooLastRequest = 0;
const YAHOO_MIN_GAP_MS = 600;
let yahooQueue: Promise<void> = Promise.resolve();

export function yahooGate(): Promise<void> {
  yahooQueue = yahooQueue.then(async () => {
    const elapsed = Date.now() - yahooLastRequest;
    if (elapsed < YAHOO_MIN_GAP_MS) {
      await new Promise<void>(r => setTimeout(r, YAHOO_MIN_GAP_MS - elapsed));
    }
    yahooLastRequest = Date.now();
  });
  return yahooQueue;
}

/**
 * Global Finnhub request gate.
 * Free-tier Finnhub keys are sensitive to burst concurrency; spacing requests
 * reduces 429 cascades that otherwise spill into Yahoo fallback.
 */
let finnhubLastRequest = 0;
const FINNHUB_MIN_GAP_MS = 350;
let finnhubQueue: Promise<void> = Promise.resolve();

export function finnhubGate(): Promise<void> {
  finnhubQueue = finnhubQueue.then(async () => {
    const elapsed = Date.now() - finnhubLastRequest;
    if (elapsed < FINNHUB_MIN_GAP_MS) {
      await new Promise<void>(r => setTimeout(r, FINNHUB_MIN_GAP_MS - elapsed));
    }
    finnhubLastRequest = Date.now();
  });
  return finnhubQueue;
}