import svgCaptcha from 'svg-captcha'

interface CaptchaRecord {
  text: string
  createdAt: number
}

const captchaStore = new Map<string, CaptchaRecord>()
const CAPTCHA_TTL = 5 * 60 * 1000

function cleanupExpired(): void {
  const now = Date.now()
  for (const [token, record] of captchaStore) {
    if (now - record.createdAt > CAPTCHA_TTL) {
      captchaStore.delete(token)
    }
  }
}

export function generateCaptcha(): { token: string; svg: string } {
  cleanupExpired()
  const { text, data: svg } = svgCaptcha.create({
    noise: 3,
    color: true,
    background: '#f8f9fa',
  })
  const token = crypto.randomUUID()
  captchaStore.set(token, { text, createdAt: Date.now() })
  return { token, svg }
}

export function verifyCaptcha(token: string, text: string): boolean {
  const record = captchaStore.get(token)
  if (!record) return false
  if (Date.now() - record.createdAt > CAPTCHA_TTL) {
    captchaStore.delete(token)
    return false
  }
  const match = record.text.toLowerCase() === text.toLowerCase()
  if (match) {
    captchaStore.delete(token)
  }
  return match
}