juicebox-rate-limits

# Juicebox Rate Limits

## Overview
Understand and implement proper rate limiting handling for Juicebox API.

## Rate Limit Tiers

| Plan | Requests/Min | Requests/Day | Searches/Month |
|------|--------------|--------------|----------------|
| Free | 10 | 100 | 500 |
| Pro | 60 | 5,000 | 25,000 |
| Enterprise | 300 | 50,000 | Unlimited |

## Instructions

### Step 1: Understand Rate Limit Headers
```typescript
// Juicebox returns these headers with every response
interface RateLimitHeaders {
  'x-ratelimit-limit': string;      // Max requests per window
  'x-ratelimit-remaining': string;  // Remaining requests
  'x-ratelimit-reset': string;      // Unix timestamp when limit resets
  'retry-after'?: string;           // Seconds to wait (only on 429)
}

function parseRateLimitHeaders(headers: Headers) {
  return {
    limit: parseInt(headers.get('x-ratelimit-limit') || '0'),
    remaining: parseInt(headers.get('x-ratelimit-remaining') || '0'),
    reset: new Date(parseInt(headers.get('x-ratelimit-reset') || '0') * 1000),
    retryAfter: parseInt(headers.get('retry-after') || '0')
  };
}
```

### Step 2: Implement Rate Limiter
```typescript
// lib/rate-limiter.ts
export class RateLimiter {
  private queue: Array<() => Promise<void>> = [];
  private processing = false;
  private lastRequestTime = 0;
  private minInterval: number;

  constructor(requestsPerMinute: number) {
    this.minInterval = 60000 / requestsPerMinute;
  }

  async execute<T>(fn: () => Promise<T>): Promise<T> {
    return new Promise((resolve, reject) => {
      this.queue.push(async () => {
        try {
          const result = await fn();
          resolve(result);
        } catch (error) {
          reject(error);
        }
      });

      this.processQueue();
    });
  }

  private async processQueue() {
    if (this.processing || this.queue.length === 0) return;
    this.processing = true;

    while (this.queue.length > 0) {
      const now = Date.now();
      const elapsed = now - this.last