import { CaptchaObj, createMathExpr } from 'svg-captcha'

/**
 * 生成验证码
 * @return {CaptchaObj}
 */
export function generate_captcha(): CaptchaObj {
  return createMathExpr({ color: true })
}

/**
 * 检查验证码
 * @param req
 * @param captcha
 * @param stored_captcha
 * @param stamp
 * @return {boolean}
 */
export function validate_captcha(req, captcha, stored_captcha, stamp): boolean {
  if (!stored_captcha || !captcha) {
    return false
  }
  if (!stamp) {
    return false
  }
  if (Date.now() - stamp > 600000) {
    return false
  }
  return stored_captcha.toUpperCase() === captcha.toUpperCase()
}