const config = require('../config.js')
const path = require('path')
const multer = require('multer')
const randomstring = require('randomstring')
const db = require('knex')(config.database)
const crypto = require('crypto')
const fs = require('fs')
const utils = require('./utilsController.js')

const uploadsController = {}

// Let's default it to only 1 try
const maxTries = config.uploads.maxTries || 1
const uploadDir = path.join(__dirname, '..', config.uploads.folder)

const storage = multer.diskStorage({
  destination: function (req, file, cb) {
    cb(null, uploadDir)
  },
  filename: function (req, file, cb) {
    // If the user has a preferred file length, make sure it follows the allowed range
    const fileLength = req.params.fileLength ? Math.min(Math.max(req.params.fileLength, config.uploads.fileLength.min), config.uploads.fileLength.max) : config.uploads.fileLength.default
    const access = i => {
      const name = randomstring.generate(fileLength) + path.extname(file.originalname)
      fs.access(path.join(uploadDir, name), err => {
        if (err) return cb(null, name)
        console.log(`A file named "${name}" already exists (${++i}/${maxTries}).`)
        if (i < maxTries) return access(i)
        // eslint-disable-next-line standard/no-callback-literal
        return cb('Could not allocate a unique file name. Try again?')
      })
    }
    access(0)
  }
})

const upload = multer({
  storage: storage,
  limits: { fileSize: config.uploads.maxSize },
  fileFilter: function (req, file, cb) {
    if (config.blockedExtensions === undefined) return cb(null, true)
    if (config.blockedExtensions.some(extension => path.extname(file.originalname).toLowerCase() === extension)) {
      // eslint-disable-next-line standard/no-callback-literal
      return cb('This file extension is not allowed.')
    }
    return cb(null, true)
  }
}).array('files[]')

uploadsController.upload = async (req, res, next) => {
  if (config.private === true) {
    await utils.authorize(req, res)
  }

  const token = req.headers.token || ''
  const user = await db.table('users').where('token', token).first()
  if (user && (user.enabled === false || user.enabled === 0)) {
    return res.json({
      success: false,
      description: 'This account has been disabled.'
    })
  }
  if (user && user.fileLength) {
    req.params.fileLength = user.fileLength
  }
  const albumid = req.headers.albumid || req.params.albumid

  if (albumid && user) {
    const album = await db.table('albums').where({ id: albumid, userid: user.id }).first()
    if (!album) {
      return res.json({
        success: false,
        description: 'Album doesn\'t exist or it doesn\'t belong to the user.'
      })
    }
    return uploadsController.actuallyUpload(req, res, user, albumid)
  }
  return uploadsController.actuallyUpload(req, res, user, albumid)
}

uploadsController.actuallyUpload = async (req, res, userid, album) => {
  upload(req, res, async err => {
    if (err) {
      console.error(err)
      return res.json({ success: false, description: err })
    }

    if (req.files.length === 0) return res.json({ success: false, description: 'no-files' })

    const files = []
    const existingFiles = []
    let iteration = 1

    req.files.forEach(async file => {
      // Check if the file exists by checking hash and size
      let hash = crypto.createHash('md5')
      let stream = fs.createReadStream(path.join(__dirname, '..', config.uploads.folder, file.filename))

      stream.on('data', data => {
        hash.update(data, 'utf8')
      })

      stream.on('end', async () => {
        const fileHash = hash.digest('hex')
        const dbFile = await db.table('files')
          .where(function () {
            if (userid === undefined) this.whereNull('userid')
            else this.where('userid', userid.id)
          })
          .where({
            hash: fileHash,
            size: file.size
          })
          .first()

        if (!dbFile) {
          files.push({
            name: file.filename,
            original: file.originalname,
            type: file.mimetype,
            size: file.size,
            hash: fileHash,
            ip: req.ip,
            albumid: album,
            userid: userid !== undefined ? userid.id : null,
            timestamp: Math.floor(Date.now() / 1000)
          })
        } else {
          uploadsController.deleteFile(file.filename).then(() => {}).catch(err => console.error(err))
          existingFiles.push(dbFile)
        }

        if (iteration === req.files.length) {
          return uploadsController.processFilesForDisplay(req, res, files, existingFiles)
        }
        iteration++
      })
    })
  })
}

uploadsController.processFilesForDisplay = async (req, res, files, existingFiles) => {
  let basedomain = config.domain
  if (files.length === 0) {
    return res.json({
      success: true,
      files: existingFiles.map(file => {
        return {
          name: file.name,
          size: file.size,
          url: `${basedomain}/${file.name}`
        }
      })
    })
  }

  await db.table('files').insert(files)
  for (let efile of existingFiles) files.push(efile)

  res.json({
    success: true,
    files: files.map(file => {
      return {
        name: file.name,
        size: file.size,
        url: `${basedomain}/${file.name}`
      }
    })
  })

  for (let file of files) {
    let ext = path.extname(file.name).toLowerCase()
    if ((config.uploads.generateThumbnails.image && utils.imageExtensions.includes(ext)) || (config.uploads.generateThumbnails.video && utils.videoExtensions.includes(ext))) {
      file.thumb = `${basedomain}/thumbs/${file.name.slice(0, -ext.length)}.png`
      utils.generateThumbs(file)
    }

    if (file.albumid) {
      db.table('albums').where('id', file.albumid).update('editedAt', file.timestamp).then(() => {})
        .catch(error => { console.log(error); res.json({ success: false, description: 'Error updating album.' }) })
    }
  }
}

uploadsController.delete = async (req, res) => {
  const user = await utils.authorize(req, res)
  const id = req.body.id
  if (id === undefined || id === '') {
    return res.json({ success: false, description: 'No file specified.' })
  }

  const file = await db.table('files')
    .where('id', id)
    .where(function () {
      if (user.username !== 'root') {
        this.where('userid', user.id)
      }
    })
    .first()

  try {
    await uploadsController.deleteFile(file.name).catch(err => {
      // ENOENT is missing file, for whatever reason, then just delete from db
      if (err.code !== 'ENOENT') throw err
    })
    await db.table('files').where('id', id).del()
    if (file.albumid) {
      await db.table('albums').where('id', file.albumid).update('editedAt', Math.floor(Date.now() / 1000))
    }
  } catch (err) {
    console.log(err)
  }

  return res.json({ success: true })
}

uploadsController.deleteFile = function (file) {
  const ext = path.extname(file).toLowerCase()
  return new Promise((resolve, reject) => {
    fs.stat(path.join(__dirname, '..', config.uploads.folder, file), (err, stats) => {
      if (err) { return reject(err) }
      fs.unlink(path.join(__dirname, '..', config.uploads.folder, file), err => {
        if (err) { return reject(err) }
        if (!utils.imageExtensions.includes(ext) && !utils.videoExtensions.includes(ext)) {
          return resolve()
        }
        file = file.substr(0, file.lastIndexOf('.')) + '.png'
        fs.stat(path.join(__dirname, '..', config.uploads.folder, 'thumbs/', file), (err, stats) => {
          if (err) {
            if (err.code !== 'ENOENT') {
              console.log(err)
            }
            return resolve()
          }
          fs.unlink(path.join(__dirname, '..', config.uploads.folder, 'thumbs/', file), err => {
            if (err) { return reject(err) }
            return resolve()
          })
        })
      })
    })
  })
}

uploadsController.list = async (req, res) => {
  const user = await utils.authorize(req, res)

  let offset = req.params.page
  if (offset === undefined) offset = 0

  const files = await db.table('files')
    .where(function () {
      if (req.params.id === undefined) this.where('id', '<>', '')
      else this.where('albumid', req.params.id)
    })
    .where(function () {
      if (user.username !== 'root') this.where('userid', user.id)
    })
    .orderBy('id', 'DESC')
    .limit(25)
    .offset(25 * offset)
    .select('id', 'albumid', 'timestamp', 'name', 'userid', 'size')

  const albums = await db.table('albums')
  let basedomain = config.domain
  let userids = []

  for (let file of files) {
    file.file = `${basedomain}/${file.name}`
    file.date = new Date(file.timestamp * 1000)
    file.date = utils.getPrettyDate(file.date)
    file.size = utils.getPrettyBytes(parseInt(file.size))

    file.album = ''

    if (file.albumid !== undefined) {
      for (let album of albums) {
        if (file.albumid === album.id) {
          file.album = album.name
        }
      }
    }

    // Only push usernames if we are root
    if (user.username === 'root') {
      if (file.userid !== undefined && file.userid !== null && file.userid !== '') {
        userids.push(file.userid)
      }
    }

    let ext = path.extname(file.name).toLowerCase()
    if ((config.uploads.generateThumbnails.image && utils.imageExtensions.includes(ext)) || (config.uploads.generateThumbnails.video && utils.videoExtensions.includes(ext))) {
      file.thumb = `${basedomain}/thumbs/${file.name.slice(0, -ext.length)}.png`
    }
  }

  // If we are a normal user, send response
  if (user.username !== 'root') return res.json({ success: true, files })

  // If we are root but there are no uploads attached to a user, send response
  if (userids.length === 0) return res.json({ success: true, files })

  const users = await db.table('users').whereIn('id', userids)
  for (let dbUser of users) {
    for (let file of files) {
      if (file.userid === dbUser.id) {
        file.username = dbUser.username
      }
    }
  }

  return res.json({ success: true, files })
}

module.exports = uploadsController