const puppeteer = require('puppeteer')
const express = require('express')
const bodyParser = require('body-parser')
const crypto = require('crypto')
const fs = require('fs')

const port = 3000
var app = express()
app.use(bodyParser.json())

const runJob = async (url) => {
  var browser
  var title = ''
  var filename = ''
  var html = ''

  try {
    browser = await puppeteer.launch({headless: true})
    const page = await browser.newPage()
    page.setViewport({ width: 1280, height: 1024 })

    // consider navigation to be finished when there are no more than 2 network connections for at least 500 ms
    await page.goto(url, {"waitUntil" : "networkidle2"})

    title = await page.title()
    filename = crypto.createHash('md5').update(url).digest('hex')
    await page.screenshot({path: 'pages/' + filename + '.png'})
    html = await page.content();
    // save file synchronously
    fs.writeFileSync('pages/' + filename + '.html', html, function(err) {
      if (err) {
        return console.log('Error writing html: ' + err)
      }
    });
  } catch (err) {
    console.log('There was an error: ' + err.message)
  } finally {
    if (browser) {
      await browser.close()
    }
  }

  return [filename, html]
}

app.get('/get_page', async function(req, res) {
  var url = req.body.url || req.query.url
  console.log('Got URL: ' + url)
  var [id, body] = await runJob(url)
  console.log('Processed ID: ' + id + ' for URL: ' + url)
  await res.send(body)
});

// handle errors
app.use((err, req, res, next) => {
  if (! err) return next()
  res.status(500)
  res.send('500: Internal server error')
})
process.setMaxListeners(0);
process.on('uncaughtException', function(error) {
  console.log('uncaughtException Error: ' + error)
})
process.on('unhandledRejection', function(error) {
 console.log('unhandledRejection Error: ' + error)
})

app.listen(port)
console.log('Server is listening on port ' + port)