Hubspot Rate Limit Survival

interface RateLimitState {
  dailyLimit: number;
  dailyRemaining: number;
  windowMs: number;
  windowMax: number;
  windowRemaining: number;
}

let rl: RateLimitState = {
  dailyLimit: 500_000, dailyRemaining: 500_000,
  windowMs: 10_000, windowMax: 100, windowRemaining: 100,
};

function updateRateLimitState(headers: Headers): void {
  if (headers.get("X-HubSpot-RateLimit-Daily"))
    rl.dailyLimit = parseInt(headers.get("X-HubSpot-RateLimit-Daily")!, 10);
  if (headers.get("X-HubSpot-RateLimit-Daily-Remaining"))
    rl.dailyRemaining = parseInt(headers.get("X-HubSpot-RateLimit-Daily-Remaining")!, 10);
  if (headers.get("X-HubSpot-RateLimit-Max"))
    rl.windowMax = parseInt(headers.get("X-HubSpot-RateLimit-Max")!, 10);
  if (headers.get("X-HubSpot-RateLimit-Remaining"))
    rl.windowRemaining = parseInt(headers.get("X-HubSpot-RateLimit-Remaining")!, 10);

  const pctUsed = 1 - rl.dailyRemaining / rl.dailyLimit;
  console.log(JSON.stringify({
    event: "hubspot_rate_limit_state",
    daily_remaining: rl.dailyRemaining,
    daily_pct_used: parseFloat(pctUsed.toFixed(4)),
    window_remaining: rl.windowRemaining,
  }));
}

class TokenBucket {
  private tokens: number;
  private lastRefillAt: number;

  constructor(
    private readonly capacity: number,
    private readonly refillRatePerMs: number,
  ) {
    this.tokens = capacity;
    this.lastRefillAt = Date.now();
  }

  consume(count = 1): number {  // returns ms to wait; 0 = immediate
    const now = Date.now();
    this.tokens = Math.min(
      this.capacity,
      this.tokens + (now - this.lastRefillAt) * this.refillRatePerMs,
    );
    this.lastRefillAt = now;
    if (this.tokens >= count) { this.tokens -= count; return 0; }
    return Math.ceil((count - this.tokens) / this.refillRatePerMs);
  }
}

// Private app, standard plan: 100 req/10s = 0.01 req/ms
// Ops Hub Enterprise: 100 req/s = 0.1 req/ms
const BUCKETS = {
  starter:            new TokenBucket(100,  10 / 10_000),
  professional:       new TokenBucket(150,  15 / 10_000),
  ops_hub_enterprise: new TokenBucket(1000, 100 / 10_000),
};

type PlanTier = keyof typeof BUCKETS;
let activeBucket: TokenBucket = BUCKETS.starter;

export function configurePlanTier(tier: PlanTier): void {
  activeBucket = BUCKETS[tier];
}

export async function acquireToken(): Promise<void> {
  const waitMs = activeBucket.consume();
  if (waitMs > 0) await new Promise((r) => setTimeout(r, waitMs));
}

function parseRetryAfterMs(headers: Headers): number | null {
  const raw = headers.get("Retry-After");
  if (!raw) return null;
  const s = parseInt(raw, 10);
  return isNaN(s) ? null : s * 1_000;
}

export async function hubspotFetch(
  path: string,
  init: RequestInit = {},
  maxAttempts = 5,
): Promise<Response> {
  for (let attempt = 1; attempt <= maxAttempts; attempt++) {
    await acquireToken();
    const res = await fetch(`https://api.hubapi.com${path}`, {
      ...init,
      headers: {
        Authorization: `Bearer ${process.env.HUBSPOT_ACCESS_TOKEN!}`,
        "Content-Type": "application/json",
        ...init.headers,
      },
    });
    updateRateLimitState(res.headers);
    if (res.ok) return res;

    const retryable = res.status === 429 || (res.status >= 500 && res.status < 600);
    if (!retryable || attempt === maxAttempts) throw new Error(`HubSpot ${res.status}: ${path}`);

    const delayMs = parseRetryAfterMs(res.headers)
      ?? Math.random() * Math.min(60_000, 500 * 2 ** attempt);
    await new Promise((r) => setTimeout(r, delayMs));
  }
  throw new Error("unreachable");
}

const BATCH_SIZE = 100; // HubSpot hard limit

function chunk<T>(arr: T[], size = BATCH_SIZE): T[][] {
  const chunks: T[][] = [];
  for (let i = 0; i < arr.length; i += size) chunks.push(arr.slice(i, i + size));
  return chunks;
}

export async function batchRead(
  objectType: "contacts" | "companies" | "deals" | "tickets",
  ids: string[],
  properties: string[],
): Promise<{ results: unknown[]; errors: unknown[] }> {
  const results: unknown[] = [];
  const errors: unknown[] = [];
  for (const batch of chunk(ids)) {
    const res = await hubspotFetch(`/crm/v3/objects/${objectType}/batch/read`, {
      method: "POST",
      body: JSON.stringify({ inputs: batch.map((id) => ({ id })), properties }),
    });
    const body = await res.json() as { results: unknown[]; errors?: unknown[] };
    results.push(...body.results);
    if (body.errors) errors.push(...body.errors);
  }
  return { results, errors };
}