const express = require('express')
const bodyParser = require('body-parser')
const path = require('path')
const fs = require('fs')
const fsPromises = fs.promises

const app = express()

require('express-async-errors')

let apps = process.env.APPS ? JSON.parse(process.env.APPS) : ['highlight-termbin', 'dyndns', 'tempfiles']
let sock = process.env.SOCKET || '/tmp/serve-lunasqu.ee.t.sock'

app.enable('trust proxy', 1)
app.disable('x-powered-by')

app.use(bodyParser.urlencoded({ extended: false }))
app.use(bodyParser.json())

function requireNoCache (file) {
  let fullPath = path.resolve(file)

  let data = require(fullPath)

  if (require.cache && require.cache[fullPath]) {
    delete require.cache[fullPath]
  }

  return data
}

async function enableApp (name) {
  let papp = path.join(__dirname, 'applications', name)
  await fsPromises.access(papp, fs.constants.F_OK)

  let runner = requireNoCache(papp)
  if (!runner) throw new Error('No such application.')
  let router = await runner()

  app.use('/' + name, router)
}

async function init () {
  for (let i in apps) {
    let papp = apps[i]
    try {
      await enableApp(papp)
      console.log(' =>', papp, 'was enabled successfully.')
    } catch (e) {
      console.error('Failed to start application', papp)
      console.error(e.stack)
    }
  }

  try { await fsPromises.unlink(sock) } catch (e) {}

  app.use(function (err, req, res, next) {
    console.error(err)
    res.status(500).end(err.message)
  })

  app.listen(sock, function () {
    console.log('Started server on', sock)
  })

  try {
    await fsPromises.access(sock, fs.constants.F_OK)
    await fsPromises.chmod(sock, 0o777)
  } catch (e) {}
}

module.exports = init