const { sendEmailCode } = require('./email')

function generateCode() {
  return Math.floor(100000 + Math.random() * 900000).toString()
}

async function sendVerificationCode(db, email) {
  const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/
  if (!emailRegex.test(email)) {
    return { success: false, error: '邮箱格式不正确' }
  }

  const codesCollection = db.collection('verification_codes')

  const recentCode = await codesCollection.findOne({
    email,
    created_at: { $gt: new Date(Date.now() - 60000) }
  })
  if (recentCode) {
    return { success: false, error: '验证码发送太频繁，请稍后再试' }
  }

  const code = generateCode()
  const result = await sendEmailCode(email, code)

  if (!result.success) {
    return { success: false, error: '验证码发送失败: ' + result.message }
  }

  await codesCollection.deleteMany({ email })

  await codesCollection.insertOne({
    email,
    code,
    created_at: new Date(),
    expires_at: new Date(Date.now() + 5 * 60 * 1000)
  })

  return { success: true }
}

async function verifyCode(db, email, code) {
  const codesCollection = db.collection('verification_codes')

  const record = await codesCollection.findOne({
    email,
    code,
    expires_at: { $gt: new Date() }
  })

  if (!record) {
    return { success: false, error: '验证码无效或已过期' }
  }

  await codesCollection.deleteMany({ email })
  return { success: true }
}

module.exports = { sendVerificationCode, verifyCode, generateCode }