const appRoot = require( 'app-root-path' )
require( 'dotenv' ).config( { 'path': `${appRoot}/.env` } )
const crs = require( 'crypto-random-string' )

const knex = require( `${appRoot}/db/knex` )
const Verifications = () => knex( 'email_verifications' )

const { getServerInfo } = require( `${appRoot}/modules/core/services/generic` )
const { sendEmail } = require( `${appRoot}/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 < 8.64e+7
}

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 }