import {moment} from "duniter/app/lib/common-libs/moment";
import {Conf} from "./types/conf";
import {ConfMail} from './types/conf'
import * as nodemailer from 'nodemailer'
import * as os from 'os'

// TODO: in confMail

const QUEUE_PERIOD = 5000
const queue: EmailContent[] = []
let conf: ConfMail|undefined

export function initConfMail(confMail: ConfMail) {
  conf = confMail

  ;(async () => {
    while (true) {
      await consumeQueue()
      await new Promise((res) => setTimeout(res, QUEUE_PERIOD))
    }
  })()
}

export async function queueEmail(subject: string, html: string, cc?: string) {
  queue.push({ subject, body: html, cc })
}

async function consumeQueue() {
  while (queue.length) {
    const mail = queue.shift()
    if (mail) {
      await sendEmail(mail.subject, mail.body, mail.cc)
    }
  }
}

async function sendEmail(subject: string, html: string, cc?: string) {

  if (!conf) {
    console.error(`Mail is not properly configured.`)
    return
  }

  console.log(`[mail] Subject: ${subject}`)
  console.log(`[mail] Body: ${html}`)
  if (!conf.enabled) {
    console.warn(`Mail is disabled.`)
    return
  }

  let transporter = nodemailer.createTransport({
    host: conf.host,
    port: conf.port,
    secure: false, // true for 465, false for other ports
    auth: {
      user: conf.username, // generated ethereal user
      pass: conf.apikey // generated ethereal password
    },
    authMethod: conf.auth,
    requireTLS: true,
  });

  // send mail with defined transport object
  let info = await transporter.sendMail({
    from: conf.from,
    to: conf.to,
    cc: (conf.cc ? [conf.cc] : []).concat(cc ? [cc] : []).join(','),
    subject,
    html
  })
}

export const mail = {

  onEstablished: (target: string, message = `Connection established for ${target}`, getHtml: () => string = () => `
      <p>
        Connection from [${os.hostname}] to ${target} established on ${moment().format('DD-MM-YYYY HH:mm:ss')}.
      </p>
    `) => {
    return async (cc?: string) => {
      await queueEmail(`[dw] [${os.hostname}] ${message}`, getHtml(), cc)
    }
  },

  onDisconnect: (target: string, message = `Connection closed for ${target}`, getErrorMessage: () => string = () => '', getHtml: (waitingDelay: number, recallDelay: number) => string = (waitingDelay: number, recallDelay: number) => `
      <p>
        Connection from [${os.hostname}] to ${target} was lost on ${moment().format('dd-MM-YYYY HH:mm:ss')}.
      </p>
      <p>
        Waiting ${(waitingDelay / 1000).toFixed(0)} seconds before trying to reconnect (${(recallDelay / 1000).toFixed(0)} seconds for recall).
      </p>
      ${getErrorMessage()}
  `) => {
    return async (waitingDelay: number, recallDelay: number, cc?: string) => {
      console.log('Waiting %s seconds...', (waitingDelay / 1000).toFixed(0))
      await queueEmail(`[dw] [${os.hostname}] ${message}`, getHtml(waitingDelay, recallDelay), cc)
    }
  },

  onRestartSuccess: (target: string, message = `Connection recovered for ${target}`, getHtml: () => string = () => `
      <p>
        Connection from [${os.hostname}] to ${target} was recovered on ${moment().format('dd-MM-YYYY HH:mm:ss')}.
      </p>
    `) => {
    return async (cc?: string) => {
      console.log(`${message}`)
      await queueEmail(`[dw] [${os.hostname}] ${message}`, getHtml(), cc)
    }
  },
}

interface EmailContent {
  subject: string
  body: string
  cc?: string
}