require('dotenv').config()
const express = require('express')
const app = express()
const path = require('path')
const mongo = require('mongodb')
const MongoClient = mongo.MongoClient
console.log('Starting with parameters:')
const parameters = ['PORT', 'MONGO_SERVER', 'MONGO_DB']
parameters.forEach(parameter => console.log(`${parameter}=${process.env[parameter]}`))
app.listen(process.env.PORT, () => {
  console.log('Listening on ' + process.env.PORT)
})

let db
const mongoUrl = `mongodb://${process.env.MONGO_SERVER}:27017`
MongoClient.connect(mongoUrl, { useNewUrlParser: true }).then(client => {
  db = client.db(process.env.MONGO_DB)
  console.log('Connected succesfully to server')
}).catch(err => console.log(err))

app.use(function(req, res, next) {
  res.header('Access-Control-Allow-Origin', '*')
  res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept')
  next()
})

app.get('/type/:type/startDate/:startDate/endDate/:endDate/sample/:sample', async (req, res) => {
  const startDate = new Date(req.params.startDate * 1000)
  const endDate = new Date(req.params.endDate * 1000)
  const sample = parseInt(req.params.sample)
  const query = {
    _id: {
      $gt: objectIdFromDate(startDate),
      $lt: objectIdFromDate(endDate)
    },
    type: req.params.type,
    value: {
      $ne: NaN
    }
  }
  try {
    const docs = await db.collection('dht22').find(query).toArray()
    const sampledDocs = docs
      .filter((value, index) => index % sample === 0)
      .map(doc => {
        return { ...doc, date: dateFromObjectId(doc._id) }
      })
    res.json(sampledDocs)
  } catch (err) {
    console.log(err)
  }
})

function objectIdFromDate(date) {
  return mongo.ObjectId(Math.floor(date.getTime() / 1000).toString(16) + '0000000000000000')
}

function dateFromObjectId(objectId) {
  return Math.floor(mongo.ObjectId(objectId).getTimestamp().getTime() / 1000)
}

app.use(express.static(path.join(__dirname, '../dist')))

app.get('/*', function(req, res) {
  res.sendFile(path.join(__dirname, '../dist/index.html'))
})

module.exports = app