import { describe, it, expect, beforeEach, vi, afterEach } from 'vitest'

// Reset module between tests so the buckets Map is fresh
let checkRateLimit: (ip: string) => boolean

beforeEach(async () => {
  vi.resetModules()
  const mod = await import('@/lib/rateLimit')
  checkRateLimit = mod.checkRateLimit
})

afterEach(() => {
  vi.useRealTimers()
})

describe('checkRateLimit', () => {
  it('allows the first request from a new IP', () => {
    expect(checkRateLimit('1.2.3.4')).toBe(true)
  })

  it('allows up to 5 requests from the same IP (MAX_TOKENS)', () => {
    const ip = '10.0.0.1'
    // first request seeds bucket with MAX_TOKENS-1 (4) tokens consumed
    expect(checkRateLimit(ip)).toBe(true) // creates bucket, tokens = 4
    expect(checkRateLimit(ip)).toBe(true) // tokens = 3
    expect(checkRateLimit(ip)).toBe(true) // tokens = 2
    expect(checkRateLimit(ip)).toBe(true) // tokens = 1
    expect(checkRateLimit(ip)).toBe(true) // tokens = 0
  })

  it('blocks the 6th request within the refill window', () => {
    const ip = '10.0.0.2'
    for (let i = 0; i < 5; i++) checkRateLimit(ip)
    expect(checkRateLimit(ip)).toBe(false)
  })

  it('tracks different IPs independently', () => {
    const ip1 = '192.168.1.1'
    const ip2 = '192.168.1.2'
    for (let i = 0; i < 5; i++) checkRateLimit(ip1)
    // ip1 exhausted, ip2 should still be allowed
    expect(checkRateLimit(ip1)).toBe(false)
    expect(checkRateLimit(ip2)).toBe(true)
  })

  it('refills tokens after the 15-minute window passes', () => {
    vi.useFakeTimers()
    const ip = '172.16.0.1'
    for (let i = 0; i < 5; i++) checkRateLimit(ip)
    expect(checkRateLimit(ip)).toBe(false)

    // Advance past REFILL_INTERVAL_MS (15 min)
    vi.advanceTimersByTime(15 * 60 * 1_000 + 1)
    expect(checkRateLimit(ip)).toBe(true)
  })

  it('does NOT refill before the 15-minute window elapses', () => {
    vi.useFakeTimers()
    const ip = '172.16.0.2'
    for (let i = 0; i < 5; i++) checkRateLimit(ip)
    expect(checkRateLimit(ip)).toBe(false)

    vi.advanceTimersByTime(14 * 60 * 1_000)
    expect(checkRateLimit(ip)).toBe(false)
  })

  it('handles "unknown" as a valid IP key', () => {
    expect(checkRateLimit('unknown')).toBe(true)
  })
})