import { beforeEach, describe, expect, it } from 'vitest';
import { TooManyRequestsError } from '@bytelyst/errors';
import { assertRateLimit, rateLimitKey, resetRateLimits } from './rate-limit.js';

describe('rate limiting', () => {
  beforeEach(() => {
    resetRateLimits();
  });

  it('normalizes missing key parts', () => {
    expect(rateLimitKey('prompt-run', '', null, 'user_1')).toBe('prompt-run:unknown:unknown:user_1');
  });

  it('allows requests up to the policy limit', () => {
    const policy = { label: 'test endpoint', max: 2, windowMs: 1_000 };

    assertRateLimit('test:user_1', policy, 1_000);
    assertRateLimit('test:user_1', policy, 1_500);

    expect(() => assertRateLimit('test:user_1', policy, 2_001)).not.toThrow();
  });

  it('throws a shared 429 error when the bucket is exhausted', () => {
    const policy = { label: 'test endpoint', max: 2, windowMs: 1_000 };

    assertRateLimit('test:user_1', policy, 1_000);
    assertRateLimit('test:user_1', policy, 1_001);

    expect(() => assertRateLimit('test:user_1', policy, 1_999)).toThrow(TooManyRequestsError);

    try {
      assertRateLimit('test:user_1', policy, 1_999);
    } catch (error) {
      expect(error).toBeInstanceOf(TooManyRequestsError);
      const rateLimitError = error as TooManyRequestsError;
      expect(rateLimitError.statusCode).toBe(429);
      expect(rateLimitError.details).toEqual({ limit: 2, windowMs: 1_000 });
    }
  });

  it('isolates buckets by key', () => {
    const policy = { label: 'test endpoint', max: 1, windowMs: 1_000 };

    assertRateLimit('test:user_1', policy, 1_000);

    expect(() => assertRateLimit('test:user_2', policy, 1_001)).not.toThrow();
  });
});