const express = require('express')
const nodemailer = require('nodemailer')
const bodyParser = require('body-parser')
const path = require('path')
const { URLSafeTimedSerializer } = require("@constemi/itsdangerjs")

require('dotenv').config()

// set up debug
let DEBUG

if (process.env.DEBUG || process.env.CROWDFUNDING_SITE_DEBUG) {
  DEBUG = true
} else {
  DEBUG = false
}

if (DEBUG) console.log('Loading website in debug mode')

// set up secret key
let secretKey
if (process.env.CROWDFUNDING_SITE_SECRET_KEY) {
  secretKey = process.env.CROWDFUNDING_SITE_SECRET_KEY
} else {
  if (DEBUG) {
    secretKey = 'NotReallyASecret'
    console.warn("Secret key is not set! We're falling back to the default one which is INSECURE and NOT TO BE USED IN PRODUCTION")
  } else {
    console.error('No secret key is set. You cannot run this in production without setting a secret key because that would be very insecure. Sorry.')
    process.exit()
  }
}

// helper function to make the serialiser
function makeSerialiser(value) {
  return URLSafeTimedSerializer(secretKey, {salt: value})
}

// set up nodemailer (if configured)
let mailer
let emailFrom
if (
  !!process.env.CROWDFUNDING_SITE_EMAIL_HOST &&
  !!process.env.CROWDFUNDING_SITE_EMAIL_USER &&
  !!process.env.CROWDFUNDING_SITE_EMAIL_PASSWORD
) {
  mailer = nodemailer.createTransport({
    host: process.env.CROWDFUNDING_SITE_EMAIL_HOST,
    port: process.env.CROWDFUNDING_SITE_EMAIL_PORT || 587,
    secure: process.env.CROWDFUNDING_SITE_EMAIL_SECURE == 'false' ? false : true,
    auth: {
      user: process.env.CROWDFUNDING_SITE_EMAIL_USER,
      pass: process.env.CROWDFUNDING_SITE_EMAIL_PASSWORD,
    }
  })

  if (!!process.env.CROWDFUNDING_SITE_EMAIL_FROM) {
    emailFrom = process.env.CROWDFUNDING_SITE_EMAIL_FROM
  } else {
    emailFrom = process.env.CROWDFUNDING_SITE_EMAIL_USER
    console.warn(`No "From" address set! Using ${emailFrom} as a default.`)
  }
} else {
  console.log("Email has not been configured! Some features won't work properly until this is set up :/")
}

async function sendMail(message) {
  if (DEBUG || !mailer) {
    console.log(`\n\n-------------------------- BEGIN EMAIL --------------------------\n`)
    console.log(`From: ${message.from}\nTo:${message.to}\nSubject:${message.subject||'(no subject)'}\n\n${message.text}`)
    console.log(`\n--------------------------- END EMAIL ---------------------------`)
    return
  } else {
    let receipt = await mailer.sendMail({
      from: message.from || emailFrom,
      to: message.to,
      subject: message.subject,
      text: message.text,
      html: message.html,
    })

    return receipt
  }
}

// get goal details
const goalPeople = Number(process.env.CROWDFUNDING_SITE_GOAL_PEOPLE) || 750
const goalRupees = Number(process.env.CROWDFUNDING_SITE_GOAL_RUPEES) || 500000

// set up knex (for database)
const knex = require('knex')({
  client:'sqlite3',
  connection:{
    filename:'./donors.sqlite'
  },
  useNullAsDefault: true
})

// schema to save pledges
let pledgeSchema = function(t) {
  t.increments('id').primary()
  t.timestamp('created_at').defaultTo(knex.fn.now()).notNullable()
  t.boolean('was_robot').defaultTo(true)

  t.integer('amount').notNullable()
  t.boolean('overseas')
  t.string('name', 128)
  t.boolean('anonymous')
  t.string('email', 128)
  t.string('phone', 32)
  t.integer('retry_times').defaultTo(10)
  t.boolean('get_newsletter').defaultTo(false)
  t.text('other_message')

  t.string('referral_code', 256)
  t.string('referrer', 128)
}

// function to make sure referral columns exist
// we need this because they were added later in the code, so
// if there are old databases they'd need to be updated.

function ensureReferralColumns(table) {
  knex.schema.hasColumn(table, 'referral_code').then(function(exists) {
    if (!exists) {
      console.debug(`No referral_code column in ${table}! Adding now...`)
      knex.schema.alterTable(table, t => {
        t.string('referral_code', 256)
      }).then(r=> console.debug(`referral_code column added to ${table}:`, r))
    }
  })

  knex.schema.hasColumn(table, 'referrer').then(function(exists) {
    if (!exists) {
      console.debug(`No referrer column in ${table}! Adding it now...`)
      knex.schema.alterTable(table, t => {
        t.string('referrer', 128)
      }).then(r=> console.debug(`referrer column added  to ${table}:`, r))
    }
  })
}

// make sure pledges table exists
knex.schema.hasTable('pledges').then(function(exists) {
  if (!exists) {
    if (DEBUG) console.debug('No pledge table exists! Creating one now...')
    return knex.schema.createTable('pledges', pledgeSchema)
  } else {
    ensureReferralColumns('pledges')
  }
})

// make sure unverified pledge table exists
knex.schema.hasTable('unverified_pledges').then(function(exists) {
  if (!exists) {
    if (DEBUG) console.debug('No unverified pledge table exists! Creating one now...')
    return knex.schema.createTable('unverified_pledges', pledgeSchema)
  } else {
    ensureReferralColumns('unverified_pledges')
  }
})

// set up bookshelf (for easy interface for database)
bookshelf = require('bookshelf')(knex)

const Pledge = bookshelf.model('Pledge', {
  tableName: 'pledges',
})

const UnverifiedPledge = bookshelf.model('UnverifiedPledge', {
  tableName: 'unverified_pledges',
})

// decide base url and port for app (can be configured)
const baseUrl = process.env.CROWDFUNDING_SITE_BASE_URL || '/'
const port = process.env.CROWDFUNDING_SITE_PORT || 5000

// set up twing
const {TwingEnvironment, TwingLoaderFilesystem} = require('twing')
let loader = new TwingLoaderFilesystem([
  path.resolve(__dirname, '..', 'src'),
])
let twing = new TwingEnvironment(loader)

// set up express
const app = express()

const router = express.Router()
app.use(baseUrl, router)

router.use(bodyParser.urlencoded({
  extended: true,
}))

// main views

// the home view is used in a couple of places, so we've moved it out
let homeView = async (req, res) => {
  if (DEBUG) console.debug('Returning home page')

  // count people
  let { total_people, total_rupees } = (await knex('pledges')
    .sum('amount as total_rupees')
    .count('* as total_people'))[0]


  // get latest pledges
  let recentPledges = (
    await Pledge
    .forge()
    .orderBy('created_at', 'DESC')
    .fetchPage({ limit: 5 })
  ).models

  if (DEBUG) console.log(`Listing ${recentPledges.length} pledges`)
  if (DEBUG && req.params.referralCode) console.log(`Referral code: ${req.params.referralCode}`)

  let referrer
  if (req.params.referralCode) {
    try {
      let pledge = await (Pledge
        .query({
          where: {
            referral_code: req.params.referralCode,
          }
        })
        .fetch())

      referrer = pledge.get('anonymous') ? 'Anonymous' : pledge.get('name')
    } catch(e) {
      if (DEBUG) console.debug(`Skipping referral ${req.params.referralCode} because not found: ${e}`)

      // if the referrer doesn't exist, send people to the normal homepage!
      res.redirect('/')
      return
    }
  }


  twing.render('index.htm.twig', {
    'goal_rupees': Number(goalRupees).toLocaleString('en-IN'),
    'goal_people': Number(goalPeople).toLocaleString('en-IN'),
    'progress_rupees': Number(total_rupees).toLocaleString('en-IN'),
    'progress_people': Number(total_people).toLocaleString('en-IN'),
    'percent_rupees': `style="width: ${total_rupees/goalRupees*100}%"`,
    'percent_people': `style="width: ${total_people/goalPeople*100}%"`,
    'recent_pledges': recentPledges,
    'referral_code': req.params.referralCode || null, // if it's there
    'referrer': referrer,
  }).then((output) => {
    res.end(output)
  })
}

router.get('/', homeView)
router.get('/r/:referralCode', homeView)

// helpers to generate and decode referrals
function randomCode() {
  let chars = 'ABCDEFGHJKLMNPQRSTUVWXYZ23456789'

  let code = ''

  for (let i=0; i<10; i++) {
    code += chars.charAt(Math.floor(Math.random() * chars.length))
  }

  return code
}
async function findReferralCode(email) {
  let referral_code

  // fetch existing referral code, if exists
  try {
    let pledge = await (Pledge
      .query({
        where: {
          email: email,
        }
      })
      .fetch())

    referral_code = pledge.get('referral_code')
    if (DEBUG) console.log(`Using existing referral code: ${referral_code}`)
  } catch(e) {
    if (e.message == 'EmptyResponse' && DEBUG) {
      console.log('No matching referrals found')
    }
  }

  if (!referral_code) {
    // no code found; create a new one and ensure uniqueness
    console.log(`Generating new referral code for: ${email}`)
    async function checkUniqueness(referral_code) {
      let a = await UnverifiedPledge.query({where: {referral_code: referral_code}}).count()
      let b = await Pledge.query({where: {referral_code: referral_code}}).count()

      return a == 0 && b == 0
    }
    do {
      referral_code = randomCode()
    } while (!checkUniqueness(referral_code))
  }

  return referral_code
}

async function findReferrer(code) {
  let email

  // first, check for an entry with this referral code
  try {
    let pledge = await (Pledge
      .query({
        where: {
          referral_code: code,
        }
      })
      .fetch())

    email = pledge.get('email')
    console.log(`Found: ${email}`)
  } catch(e) {
    if (e.message == 'EmptyResponse' && DEBUG) {
      console.log('No matching referrals found')
    } else {
      console.error(e)
    }

    // next, check for an entry with this email
    // (maybe it's already been converted from code to email)
    try {
      let pledge = await (Pledge
        .query({
          where: {
            email: code,
          }
        })
        .fetch())

      email = pledge.get('email')
      console.log('it seems to be')
    } catch(e) {
      if (e.message == 'EmptyResponse' && DEBUG) {
        console.debug('No matching emails found either')
      } else {
        console.error(e)
      }

      return null
    }
  }

  return email
}

// function to validate pledges before saving
async function validatePledge(body, PledgeModel = Pledge) {
  // errors get saved here
  let errors = []

  let was_robot = body.was_robot
  if(was_robot != 'no') {
    errors.push('Only humans are allowed to donate money. Robots are too digital 🤖')
  }

  let amount = body.amount
  if (!amount || amount == 'custom') {
    amount = body['amount-custom']
  }
  if (!amount || amount <= 0) {
    errors.push('Pledge amount too small. Please choose at least a rupee!')
  }
  try {
    amount = Number(amount)
  } catch (err) {
    errors.push('Invalid amount. Please choose a positive number!')
  }

	let name = body.name
	if (name.length <=0) {
		errors.push('What is your name? You can be anonymous to the world but at least we should know...')
	}

	let anonymous = body.anonymous == 'on' ? true : false

	let email = body.email
	if (email.length < 5) {
		errors.push('Please enter a valid email address')
	}

	let phone = body.phone

  let retry_times
  try {
    retry_times = body.retry_times
  } catch (err) {
    errors.push('Invalid retry count. Please choose a positive number!')
  }

	let get_newsletter = body.get_newsletter == 'yes' ? true : false
	let overseas = body.overseas == 'yes' ? true : false
	let other_message = body.other_message

  // manage referrals
  let referral_code = await findReferralCode(email)
  let referrer = null

  console.log('ref co', body.referral_code)
  if (body.referral_code) {
    try {
      referrer = await findReferrer(body.referral_code)
    } catch (e) {
      console.debug(`Error loading referrer: ${e}`)
    }
  }

	// enter the info
	let pledge = new PledgeModel() // may be Pledge or UnverifiedPledge
	pledge.set('was_robot', was_robot)
	pledge.set('amount', amount)
	pledge.set('overseas', overseas)
	pledge.set('name', name)
	pledge.set('anonymous', anonymous)
	pledge.set('email', email)
	pledge.set('phone', phone)
  pledge.set('retry_times', retry_times)
	pledge.set('get_newsletter', get_newsletter)
	pledge.set('other_message', other_message)

  pledge.set('referral_code', referral_code)
  pledge.set('referrer', referrer)

  // return it all!
  return {
    pledge: pledge,
    errors: errors,
  }
}

router.post('/pledge', async (req, res) => {
  if (DEBUG) console.debug('New pledge:', req.body)

  // check that the right submit button was pressed
  let submit = req.body.submit
  if (submit != 'Save Pledge') {
		errors.push("This request seems to have been tampered with. Are you sure it wasn't you doing the tampering?")
	}

  // process the pledge with our handy function
  let {pledge, errors} = await validatePledge(req.body, UnverifiedPledge)

  // fail if there were errors
  if (!!errors.length) {
    let output = await twing.render('form-errors.htm.twig', {
      errors: errors,
    })

    res.send(output)
    return
	}

  // save if there weren't
	if (DEBUG) console.debug (`Saving pledge: ${JSON.stringify(pledge)}`)
	try {
		await pledge.save()
	} catch (err) {

    let output = await twing.render('error.htm.twig', {
      error: "Sorry, something went wrong while saving your pledge and we don't know what in was. This website is still in beta so we do have a glitches once in a while. Apologies and please try again...🙁",
    })

    res.send(output)
    return
	}

  // check for existing pledge
  let existingPledge
  try {
    existingPledge = await (Pledge
      .query({
        where: {
          'email': pledge.get('email'),
          'amount': pledge.get('amount'),
        },
      })
    .orderBy('created_at', 'DESC')
    .fetch())
  } catch(e) {
    if (e.message == 'EmptyResponse' && DEBUG) {
      console.debug('No existing pledge')
    } else {
      console.warn(`Weird error happened: ${e}`)
    }
  }

  // generate verification link
  let serialiser = makeSerialiser(pledge.get('email'))
  let verificationLink = `${req.protocol}://${req.hostname}/verify?email=${encodeURIComponent(pledge.get('email'))}&key=${encodeURIComponent(serialiser.dumps(pledge.get('amount')))}`

  // send out the email, along with existing pledge deets
  console.debug(`Verification link generated: ${verificationLink}`)

  let text = `Hi ${pledge.get('name')},
Thank you so much for your pledge of ₹${Number(pledge.get('amount')).toLocaleString('en-IN')} to Snipette!
To finish the pledge, please verify your email by clicking the link below:

${verificationLink}

If you have any questions, don't hesitate to reach out: you can drop a line
anytime to editors@snipettemag.com.

Thanks,
The Snipette Team`

  // to make things snappier, we don't `await` for the sending to finish.
  let receipt = sendMail({
    to: req.body.email,
    subject: `Finish ${existingPledge ? 'updating' : 'saving'} your pledge to Snipette`,
    text: text,
  })

  // return the success page
  twing.render('pledge.htm.twig', {
    'email': pledge.get('email'),
  }).then((output) => {
    res.send(output)
  })
})

// save pledge after verification complete
router.get('/verify', async (req, res) => {
  if (DEBUG) console.debug('Validating pledge:', req.query)

  // unpack verification link (unless it's expired)
  let serialiser = makeSerialiser(req.query.email)
  let amount

  try {
    amount = serialiser.loads(req.query.key, 300) // number in seconds
  } catch(e) {
    if (e.name == 'SignatureExpired') {

      let output = await twing.render('error.htm.twig', {
        error: "Sorry, looks like your link has expired. Please go back and try pledging again. Hopefully you'll manage it quicker this time 😛",
      })

      res.send(output)
      return
    } else {

      let output = await twing.render('error.htm.twig', {
        error: "An unknown error occurred. Please generate a new link and try again. Sorry for the inconvenience 🤦",
      })

      res.send(output)
      return
    }
  }

  // check against database
  let pledge
  try {
    pledge = await (UnverifiedPledge
      .query({
        where: {
          'email': req.query.email,
          'amount': amount,
        },
      })
    .orderBy('created_at', 'DESC')
    .fetch())
  } catch(e) {
    if (e.name == 'EmptyResponse') {

      let output = await twing.render('error.htm.twig', {
        error: "That pledge was not found in our records. Are you sure you made it? 🔎",
      })

      res.send(output)
      return
    } else {

      let output = await twing.render('error.htm.twig', {
        error: "An unknown error occurred. Please generate a new link and try again. Sorry for the inconvenience 🤦",
      })

      res.send(output)
      return
    }
  }

  // prepare our new pledge
  let newPledge = new Pledge()

  newPledge.set('was_robot', pledge.get('was_robot'))
	newPledge.set('amount', pledge.get('amount'))
	newPledge.set('overseas', pledge.get('overseas'))
	newPledge.set('name', pledge.get('name'))
	newPledge.set('anonymous', pledge.get('anonymous'))
	newPledge.set('email', pledge.get('email'))
	newPledge.set('phone', pledge.get('phone'))
  newPledge.set('retry_times', pledge.get('retry_times'))
	newPledge.set('get_newsletter', pledge.get('get_newsletter'))
	newPledge.set('other_message', pledge.get('other_message'))

  newPledge.set('referral_code', await findReferralCode(pledge.get('email')))

  // set referrer in priority: old pledge > new pledge
  try {
    let oldPledge = await (Pledge
      .query({
        where: {
          email: req.query.email,
        }
      })
      .fetch())

    newPledge.set('referrer',
      oldPledge.get('referrer') || pledge.get('referrer') || null)
  } catch(e) {
    if (e.message == 'EmptyResponse' && DEBUG) {
      console.log('No matching referrals found')
    } else {
      console.error(e)
    }

    newPledge.set('referrer',  pledge.get('referrer') || null)
  }

  console.log(`Saved referrer: ${newPledge.get('referrer')}`)

  // destroy previous pledges by that user
  try {
    await (Pledge
      .query({
        where: {
          email: req.query.email,
        }
      })
      .destroy())
  } catch(e) {
    if (e.message != 'No Rows Deleted') throw e
  }

  // save the new pledge
  await newPledge.save()

  // send the confirmation email
  let referralLink = `${req.protocol}://${req.hostname}/?ref=${newPledge.get('referral_code')}`
  let text = `Hi ${pledge.get('name')},
Your pledge of ₹${Number(pledge.get('amount')).toLocaleString('en-IN')} to Snipette Analog has been saved!

Thank you so much for your support. Once we hit our goals, we will contact
you to make the final payment. Meanwhile, here are the details of your
pledge for reference:

	Name: ${pledge.get('name')}
	Pledge amount: ${Number(pledge.get('amount')).toLocaleString('en-IN')}${pledge.overseas ? ' (plus $25 for shipping)' : ''}
	Email: ${pledge.get('email')}
	Phone: ${pledge.get('phone') || 'not provided'}

	Extra message:
	${pledge.get('other_message') || '[no message sent]'}

	We will attempt to contact you ${pledge.get('retry_times') <= 1 ? 'only once' :  String(pledge.get('retry_times'))  + ' times'} before giving up.

You can update your pledge by going to the crowdfunding homepage and saving
a pledge with the same email address as you used before.

If you have any questions, don't hesitate to reach out: you can drop a line
anytime to editors@snipettemag.com.

### Share for Stickers!

Money helps, but we need people too—and that's where you can help! Here's your
unique referral link:

  ${referralLink}

Get 5 or more of your friends to sign up using that link, and, once we collect
the money and start printing, we'll send you a free pack of Snipette stickers!

Thanks,
The Snipette Team`

  // to make things snappier, we don't `await` for the sending to finish
  let receipt = sendMail({
    to: pledge.get('email'),
    subject: `Your pledge has been saved!`,
    text: text,
  })

  // Send confirmation message
  res.redirect(`/thanks?ref=${newPledge.get('referral_code')}`)
})

router.get('/thanks', async (req, res) => {
  // validate referral code
  if (!!req.query.ref && !await findReferrer(req.query.ref)) {
    if (DEBUG) console.debug(`Invalid referral: redirecting to normal page`)
    res.redirect('/thanks')
    return
  }

  let output = await twing.render('thanks.htm.twig', {
    referral_code: req.query.ref,
  })

  res.send(output)
  return
})

router.get('/pledges', async (req, res) => {
  if (DEBUG) console.debug('Returning pledges list')

  // count people
  let { total_people, total_rupees } = (await knex('pledges')
    .sum('amount as total_rupees')
    .count('* as total_people'))[0]


  // get latest pledges
  let recentPledges = (
    await Pledge
    .forge()
    .orderBy('created_at', 'DESC')
    .fetchAll()
  ).models

  if (DEBUG) console.log(`Listing ${recentPledges.length} pledges`)

  twing.render('pledges.htm.twig', {
    'recent_pledges': recentPledges,
  }).then((output) => {
    res.send(output)
  })
})

router.get('/back-out', async (req, res) => {
  if (DEBUG) console.debug('Backing out:', req.query)

  // unpack verification link (unless it's expired)
  let serialiser = makeSerialiser(req.query.email)
  let staySubscribed

  try {
    // we allow them a month to do this
    staySubscribed = serialiser.loads(req.query.key, 60 * 60 * 24 * 30)

    // clean up the variable
    if (staySubscribed == 'yes' || staySubscribed == 'true') {
      staySubscribed = true
    } else {
      staySubscribed = false
    }
  } catch(e) {
    if (e.name == 'SignatureExpired') {

      let output = await twing.render('error.htm.twig', {
        error: "It looks like you've clicked on the link of a very old email! Nothing lasts forever, including verification links, so if you're having trouble please contact <a href='mailto:editors@snipettemag.com'>editors@snipettemag.com</a>. Sorry for the inconvenience 🙁",
      })

    } else {

      let output = await twing.render('error.htm.twig', {
        error: "An unknown error occurred, and our robots can't figure out what it is. Please contact <a href='mailto:editors@snipettemag.com'>editors@snipettemag.com</a> for help. Sorry for the inconvenience 🤦",
      })

    }

    res.send(output)
    return
  }

  // now that we've got past that check...
  let pledge
  try {
    pledge = await (Pledge
      .query({
        where: {
          'email': req.query.email,
        },
      })
      .orderBy('created_at', 'DESC')
      .fetch())
  } catch(e) {
    if (e.name == 'EmptyResponse') {
      let output = await twing.render('error.htm.twig', {
        error: "That pledge was not found in our records. Are you sure you made it? 🔎",
      })

      res.send(output)
      return
    } else {

      let output = await twing.render('error.htm.twig', {
        error: "An unknown error occurred, and we can't figure out what it is. Please contact <a href='mailto:editors@snipettemag.com'>editors@snipettemag.com</a> for help (we're guessing you're trying to unsubscribe, in which case we'll handle it immediately upon receiving your email). Sorry for the inconvenience 🤦",
      })

      res.send(output)
      return
    }
  }

  // update settings for our new pledge
  pledge.set('backed_out', true)
  pledge.set('unsubscribed', !staySubscribed)

  // save the new pledge

  await pledge.save()

  // send the confirmation email
  let text = `Hi ${pledge.get('name')},
We have received your back-out request for your pledge of ${Number(pledge.get('amount')).toLocaleString('en-IN')}${pledge.get('overseas') ? ' (plus $25 for shipping)' : ''}. We have removed you from our list and you will receive no further emails regarding collecting your contribution.${staySubscribed ? ' However, you will still receive general crowdfunding updates and are welcome to join back again later.' : ''}

If you think this was a mistake, please reply to this email and one of us will get back to you.

We realise that some people may want to continue supporting Snipette even if it doesn't make sense for them to go with the original pledge. You are always welcome to subscribe directly at: https://snipettemag.com/subscribe/

Thank you for your support so far, and apologies for the fact that it didn't work out quite as expected this time.

Thanks,
The Snipette Team`

  // to make things snappier, we won't `await` for the sending to finish
  let receipt = sendMail({
    to: pledge.get('email'),
    subject: 'Pledge withdrawn from Snipette crowdfunding',
    text: text,
  })

  // Send confirmation message
  res.redirect('/bye')
})

router.get('/bye', async (req, res) => {

  let output = await twing.render('bye.htm.twig', {})

  res.send(output)
  return
})

router.use(express.static('src/assets'))

// start the listener!
if (!module.parent) {
  app.listen(port, () => {
    console.log(`Server is up at port ${port}`)
  })
}

// end note: in case we want to import this somewhere for testing
module.exports = {
  knex,
  bookshelf,
  Pledge,
  UnverifiedPledge,
  router,
  makeSerialiser,
}