const koa = require('koa')
const koaRouter = require('@koa/router')
const bodyParser = require('koa-bodyparser')
const nodemailer = require('nodemailer')
const cors = require('koa-cors')
const proxyaddr = require('proxy-addr')
const { RateLimiterMemory } = require('rate-limiter-flexible')

const app = new koa()
app.proxy = true;
app.use(cors({ methods: 'POST' }))
app.use(bodyParser())

const router = new koaRouter()

const { contacts, mailConfig, rateConfig } = require(process.env.CONTACT_CONFIG || './config.json')

if (!contacts || !mailConfig || !rateConfig) {
  throw new Error("Incomplete config")
}

const rateLimit = new RateLimiterMemory(rateConfig)
const transport = nodemailer.createTransport(mailConfig)

transport.verify()
  .then(() => console.log(`Email transport ready`))
  .catch((err) => {
    console.error('Cannot verify email transport');
    console.error(err);
    process.exit(1);
  })

router.post('/api/contact/:id', async (ctx) => {
  const { params: { id }, request, response } = ctx

  // check if we have an ID
  if (!contacts[id]) {
    response.status = 400
    response.body = {
      error: `Invalid contact id "${id}"`
    }
    return
  }

  // check for request properties
  const { name, email, phone, message } = request.body
  if (!name || !email || !message) {
    ctx.status = 400
    ctx.body = {
      status: 'error',
      message: 'invalid request'
    }
    return
  }

  // check rate limit
  const source = proxyaddr(request, 'loopback')
  try {
    // only counting as 1 point per request
    await rateLimit.consume(source, 1)
  } catch (err) {
    ctx.status = 429
    ctx.set('Retry-After', err.msBeforeNext / 1000)
    ctx.body = {
      status: 'ratelimit',
      message: 'Too many messages, play nice friend'
    }
    return
  }

  const contact = contacts[id]

  const emailBody =
    `You have received a message via ${contact.site} from ${name}:

Contact info:
  - Name: ${name}
  - Email: ${email}
  - Phone: ${phone || 'None supplied'}

Message:

${message}
`

  console.log(`Received new message:\n${JSON.stringify({ name, email, phone, message, ip: source }, null, 2)}`)
  await transport.sendMail({
    from: `tempest.dev Mailer <${mailConfig.from || mailConfig.auth.user}>`,
    to: contact.address,
    subject: contact.subject,
    text: emailBody
  })

  ctx.status = 200
  ctx.body = {
    status: 'Message sent'
  }
})

app
  .use(router.routes())
  .use(router.allowedMethods())
  .listen(process.env.PORT || 3000)