const loki = require('lokijs')
const db = new loki('DB')
const mediaDB = db.addCollection('Media')
const { Readable, PassThrough } = require('stream')

module.exports = srv => {
  srv.before('CREATE', 'Media', req => {
    const obj = mediaDB.insert({ media: '' })
    req.data.id = obj.$loki
  })

  srv.on('UPDATE', 'Media', (req, next) => {
    const url = req._.req.path
    if (url.includes('content')) {
      const id = req.data.id
      const obj = mediaDB.get(id)
      if (!obj) {
        req.reject(404, 'No record found for the ID')
        return
      }
      const stream = new PassThrough()
      const chunks = []
      stream.on('data', chunk => {
        chunks.push(chunk)
      })
      stream.on('end', () => {
        obj.media = Buffer.concat(chunks).toString('base64')
        mediaDB.update(obj)
      })
      req.data.content.pipe(stream)
    } else return next()
  })

  srv.on('READ', 'Media', (req, next) => {
    const url = req._.req.path
    if (url.includes('content')) {
      const id = req.data.id
      const mediaObj = mediaDB.get(id)
      if (!mediaObj) {
        req.reject(404, 'Media not found for the ID')
        return
      }
      const decodedMedia = Buffer.from(
        mediaObj.media.split(';base64,').pop(),
        'base64'
      )
      return _formatResult(decodedMedia)
    } else return next() //> delegate to next/default handlers
  })

  srv.on('DELETE', 'Media', (req, next) => {
    const id = req.data.id
    mediaDB
      .chain()
      .find({ $loki: id })
      .remove()
    return next() //> delegate to next/default handlers
  })

  function _formatResult (decodedMedia) {
    const readable = new Readable()
    const result = new Array()
    readable.push(decodedMedia)
    readable.push(null)
    result.push({ value: readable })
    return result
  }
}