import { describe, expect, it, vi } from 'vitest';
import { createRateLimiter, createRedisRateLimiter } from '../src/rate-limit.js';

describe('rate limiter', () => {
  it('enforces request and spend windows', () => {
    let time = 0;
    const limiter = createRateLimiter({ now: () => time });
    expect(limiter.check('ip').allowed).toBe(true);
    expect(limiter.check('ip').allowed).toBe(true);
    expect(limiter.check('ip').allowed).toBe(false);
    time = 1_001;
    expect(limiter.check('ip').allowed).toBe(true);
    limiter.recordCost('ip', 15);
    expect(limiter.check('ip').allowed).toBe(false);
    time = 5 * 60 * 60 * 1_000 + 1_002;
    expect(limiter.check('ip').allowed).toBe(true);
  });

  it('keeps clients independent', () => {
    const limiter = createRateLimiter();
    expect(limiter.check('a').allowed).toBe(true);
    expect(limiter.check('a').allowed).toBe(true);
    expect(limiter.check('a').allowed).toBe(false);
    expect(limiter.check('b').allowed).toBe(true);
  });

  it('uses Redis scripts and namespaces keys by client IP', async () => {
    const client = { eval: vi.fn().mockResolvedValueOnce([1]).mockResolvedValueOnce(1) };
    const limiter = createRedisRateLimiter({ client, now: () => 10_000, keyPrefix: 'test:limits' });

    await expect(limiter.check('2001:db8::1')).resolves.toEqual({ allowed: true });
    await limiter.recordCost('2001:db8::1', 1.25);

    expect(client.eval).toHaveBeenCalledTimes(2);
    expect(client.eval.mock.calls[0][1].keys).toEqual([
      'test:limits:{2001%3Adb8%3A%3A1}:requests',
      'test:limits:{2001%3Adb8%3A%3A1}:spend',
      'test:limits:{2001%3Adb8%3A%3A1}:sequence',
    ]);
    expect(client.eval.mock.calls[1][1].arguments).toEqual(['10000', '-17990000', '1.25', '18000000']);
  });

  it('converts Redis denials into rate-limit responses', async () => {
    const client = { eval: vi.fn().mockResolvedValue([0, 'spend', 1_001]) };
    const limiter = createRedisRateLimiter({ client, now: () => 10_000 });
    await expect(limiter.check('ip')).resolves.toEqual({ allowed: false, reason: 'spend', retryAfter: 2 });
  });
});