const crs = require('crypto-random-string')

const knex = require('@/db/knex')
const Verifications = () => knex('email_verifications')

const { getServerInfo } = require('@/modules/core/services/generic')
const { sendEmail } = require('@/modules/emails')

const sendEmailVerification = async ({ recipient }) => {
  // we need to validate email here, since we'll send it out,
  // even if technically there is no chance ATM that an incorrect addr comes in
  const serverInfo = await getServerInfo()
  const existingVerifications = await Verifications().where({ email: recipient })
  if (existingVerifications.some((ver) => isVerificationValid(ver)))
    throw new Error(
      'You already have a valid verification message, please check your inbox'
    )
  const verificationId = await createEmailVerification({ email: recipient })
  const verificationLink = new URL(
    `auth/verifyemail?t=${verificationId}`,
    process.env.CANONICAL_URL
  )
  const { text, html, subject } = await prepareMessage({ verificationLink, serverInfo })
  return await sendEmail({
    to: recipient,
    subject,
    text,
    html
  })
}

const isVerificationValid = ({ createdAt }) => {
  const timeDiff = Math.abs(Date.now() - new Date(createdAt))
  return timeDiff < 8.64e7
}

const prepareMessage = async ({ verificationLink, serverInfo }) => {
  const subject = `Speckle Server ${serverInfo.name} email verification`
  const text = `
Hello!

You have just registered to ${serverInfo.name} Speckle Server,
 or initiated the email verification process manually.

To finalize the verification process, follow the link below:

${verificationLink}

Warm regards,
Speckle
---
This email was sent from ${serverInfo.name} at ${process.env.CANONICAL_URL},
 deployed and managed by ${serverInfo.company}.
  `

  const html = `
Hello!
<br>
<br>

You have just registered to ${serverInfo.name} Speckle Server,
 or initiated the email verification process manually.

<br>
<br>

To finalize the verification process,
 please <b><a href="${verificationLink}" rel="notrack">click here</a>!</b>
<br>
<br>
Warm regards,
<br>
Speckle 
<br>
<br>
<img 
 src="https://speckle.systems/content/images/2021/02/logo_big-1.png"
 style="width:30px; height:30px;">
<br>
<br>
<caption style="size:8px; color:#7F7F7F; width:400px; text-align: left;">
This email was sent from the
 <a href="${process.env.CANONICAL_URL}">${serverInfo.name}</a>,
 deployed and managed by ${serverInfo.company}.
</caption>
  `

  return { text, html, subject }
}

const createEmailVerification = async ({ email }) => {
  const verification = {
    id: crs({ length: 20 }),
    email
  }
  await Verifications().insert(verification)
  return verification.id
}

module.exports = { sendEmailVerification, isVerificationValid }