const blake3 = require('blake3')
const contentDisposition = require('content-disposition')
const fetch = require('node-fetch')
const fs = require('fs')
const path = require('path')
const randomstring = require('randomstring')
const searchQuery = require('search-query-parser')
const paths = require('./pathsController')
const perms = require('./permissionController')
const utils = require('./utilsController')
const ClientError = require('./utils/ClientError')
const ServerError = require('./utils/ServerError')
const config = require('./../config')
const logger = require('./../logger')

/** Deprecated config options */

if (config.uploads.cacheFileIdentifiers) {
  logger.error('Config option "uploads.cacheFileIdentifiers" is DEPRECATED.')
  logger.error('There is now only "uploads.queryDatabaseForIdentifierMatch" for a similar behavior.')
}

const self = {
  onHold: new Set() // temporarily held random upload identifiers
}

/** Preferences */

const fileIdentifierLengthFallback = 32
const fileIdentifierLengthChangeable = !config.uploads.fileIdentifierLength.force &&
  typeof config.uploads.fileIdentifierLength.min === 'number' &&
  typeof config.uploads.fileIdentifierLength.max === 'number'

const maxSize = parseInt(config.uploads.maxSize)
const maxSizeBytes = maxSize * 1e6
const urlMaxSize = parseInt(config.uploads.urlMaxSize)
const urlMaxSizeBytes = urlMaxSize * 1e6

const maxFilesPerUpload = 20

const chunkedUploads = config.uploads.chunkSize &&
  typeof config.uploads.chunkSize === 'object' &&
  config.uploads.chunkSize.default
const chunkedUploadsTimeout = config.uploads.chunkSize.timeout || 1800000
const chunksData = {}
// Hard-coded min chunk size of 1 MB (e.g. 50 MB = max 50 chunks)
const maxChunksCount = maxSize
// Use fs.copyFile() instead of fs.rename() if chunks dir is NOT inside uploads dir
const chunksCopyFile = !paths.chunks.startsWith(paths.uploads)

const extensionsFilter = Array.isArray(config.extensionsFilter) &&
  config.extensionsFilter.length
const urlExtensionsFilter = Array.isArray(config.uploads.urlExtensionsFilter) &&
  config.uploads.urlExtensionsFilter.length

// Only disable hashing if explicitly disabled in config file
const enableHashing = config.uploads.hash === undefined
  ? true
  : Boolean(config.uploads.hash)

const queryDatabaseForIdentifierMatch = config.uploads.queryDatabaseForIdentifierMatch ||
  config.uploads.queryDbForFileCollisions // old config name for identical behavior

const uploadsPerPage = config.dashboard
  ? Math.max(Math.min(config.dashboard.uploadsPerPage || 0, 100), 1)
  : 25

/** Chunks helper class & function **/

class ChunksData {
  constructor (uuid) {
    this.uuid = uuid
    this.root = path.join(paths.chunks, this.uuid)
    this.filename = 'tmp'
    this.path = path.join(this.root, this.filename)
    this.chunks = 0
    this.writeStream = null
    this.hashStream = null
    // Immediately mark this chunked upload as currently processing
    this.processing = true
  }

  onTimeout () {
    self.cleanUpChunks(this.uuid)
  }

  setTimeout (delay) {
    this.clearTimeout()
    this._timeout = setTimeout(this.onTimeout.bind(this), delay)
  }

  clearTimeout () {
    if (this._timeout) {
      clearTimeout(this._timeout)
    }
  }
}

const initChunks = async uuid => {
  if (chunksData[uuid] === undefined) {
    chunksData[uuid] = new ChunksData(uuid)

    const exist = await paths.access(chunksData[uuid].root)
      .catch(err => {
        // Re-throw error only if not directory is missing error
        if (err.code !== 'ENOENT') throw err
        return false
      })
    if (!exist) {
      await paths.mkdir(chunksData[uuid].root)
    }

    // Init write & hasher streams
    chunksData[uuid].writeStream = fs.createWriteStream(chunksData[uuid].path, { flags: 'a' })
    chunksData[uuid].hashStream = enableHashing && blake3.createHash()
  } else if (chunksData[uuid].processing) {
    // Wait for the first spawned init tasks
    throw new ClientError('Previous chunk upload is still being processed. Parallel chunked uploads is not supported.')
  }

  // Reset timeout
  chunksData[uuid].setTimeout(chunkedUploadsTimeout)
  return chunksData[uuid]
}

/** Helper functions */

self.isExtensionFiltered = extname => {
  // If empty extension needs to be filtered
  if (!extname && config.filterNoExtension) return true

  // If there are extensions that have to be filtered
  if (extname && extensionsFilter) {
    const match = config.extensionsFilter.includes(extname.toLowerCase())
    const whitelist = config.extensionsFilterMode === 'whitelist'
    if ((!whitelist && match) || (whitelist && !match)) return true
  }

  return false
}

self.parseFileIdentifierLength = fileLength => {
  if (!config.uploads.fileIdentifierLength) return fileIdentifierLengthFallback

  const parsed = parseInt(fileLength)
  if (isNaN(parsed) ||
    !fileIdentifierLengthChangeable ||
    parsed < config.uploads.fileIdentifierLength.min ||
    parsed > config.uploads.fileIdentifierLength.max) {
    return config.uploads.fileIdentifierLength.default || fileIdentifierLengthFallback
  } else {
    return parsed
  }
}

self.getUniqueUploadIdentifier = async (length, extension = '', res) => {
  for (let i = 0; i < utils.idMaxTries; i++) {
    const identifier = randomstring.generate(length)

    if (queryDatabaseForIdentifierMatch) {
      // If must query database for identifiers matches
      if (self.onHold.has(identifier)) {
        logger.debug(`Identifier ${identifier} is currently held by another upload (${i + 1}/${utils.idMaxTries}).`)
        continue
      }

      // Put token on-hold (wait for it to be inserted to DB)
      self.onHold.add(identifier)

      const file = await utils.db.table('files')
        .whereRaw('?? like ?', ['name', `${identifier}.%`])
        .select('id')
        .first()
      if (file) {
        self.onHold.delete(identifier)
        logger.debug(`Identifier ${identifier} is already in use (${i + 1}/${utils.idMaxTries}).`)
        continue
      }

      // Unhold identifier once the Response has been sent
      if (res) {
        if (!res.locals.identifiers) {
          res.locals.identifiers = []
          res.once('finish', () => { self.unholdUploadIdentifiers(res) })
        }
        res.locals.identifiers.push(identifier)
      }
    } else {
      // Otherwise, check for physical files' full name matches
      try {
        const name = identifier + extension
        await paths.access(path.join(paths.uploads, name))
        logger.debug(`${name} is already in use (${i + 1}/${utils.idMaxTries}).`)
        continue
      } catch (error) {
        // Re-throw non-ENOENT error
        if (error & error.code !== 'ENOENT') throw error
      }
    }

    // Return the random identifier only
    return identifier
  }

  throw new ServerError('Failed to allocate a unique name for the upload. Try again?')
}

self.unholdUploadIdentifiers = res => {
  if (!res.locals.identifiers) return

  for (const identifier of res.locals.identifiers) {
    self.onHold.delete(identifier)
    logger.debug(`Unheld identifier ${identifier}.`)
  }

  delete res.locals.identifiers
}

self.assertRetentionPeriod = (user, age) => {
  if (!utils.retentions.enabled) {
    return null
  }

  // _ is special key for non-registered users (no auth requests)
  const group = user ? perms.group(user) : '_'
  if (!group || !utils.retentions.periods[group]) {
    throw new ClientError('You are not eligible for any file retention periods.', { statusCode: 403 })
  }

  let parsed = parseFloat(age)
  if (Number.isNaN(parsed) || age < 0) {
    parsed = utils.retentions.default[group]
  } else if (!utils.retentions.periods[group].includes(parsed)) {
    throw new ClientError('You are not eligible for the specified file retention period.', { statusCode: 403 })
  }

  if (!parsed && !utils.retentions.periods[group].includes(0)) {
    throw new ClientError('Permanent uploads are not permitted.', { statusCode: 403 })
  }

  return parsed
}

self.parseStripTags = stripTags => {
  if (!config.uploads.stripTags) return false

  if (config.uploads.stripTags.force || stripTags === undefined) {
    return config.uploads.stripTags.default
  }

  return Boolean(parseInt(stripTags))
}

/** File uploads */

self.upload = async (req, res) => {
  // Assert Request type
  // Multipart for regular uploads, JSON for URL uploads
  const isMultipart = req.is('multipart/form-data')
  const isJson = req.is('application/json')
  if (!isMultipart && !isJson) {
    throw new ClientError('Request Content-Type must be either multipart/form-data or application/json.')
  }

  if (config.privateUploadGroup) {
    if (!req.locals.user || !perms.is(req.locals.user, config.privateUploadGroup)) {
      throw new ClientError(config.privateUploadCustomResponse || 'Your usergroup is not permitted to upload new files.', { statusCode: 403 })
    }
  }

  let albumid = parseInt(req.headers.albumid || (req.path_parameters && req.path_parameters.albumid))
  if (isNaN(albumid)) albumid = null

  const age = self.assertRetentionPeriod(req.locals.user, req.headers.age)

  if (isMultipart) {
    return self.actuallyUpload(req, res, { albumid, age })
  } else {
    // Parse POST body
    req.body = await req.json()
    return self.actuallyUploadUrls(req, res, { albumid, age })
  }
}

self.actuallyUpload = async (req, res, data = {}) => {
  // Init empty Request.body and Request.files
  req.body = {}
  req.files = []

  const unfreezeChunksData = async () => {
    req.files.forEach(file => {
      if (!file.chunksData) return
      file.chunksData.processing = false
    })
  }

  const cleanUpFiles = async () => {
    // Unhold identifiers generated via self.getUniqueUploadIdentifier()
    self.unholdUploadIdentifiers(res)

    // Unlink temp files
    return Promise.all(req.files.map(async file => {
      if (!file.filename) return
      return utils.unlinkFile(file.filename).catch(logger.error)
    }))
  }

  await req.multipart({
    // https://github.com/mscdex/busboy/tree/v1.6.0#exports
    // This would otherwise defaults to latin1
    defParamCharset: 'utf8',
    limits: {
      fileSize: maxSizeBytes,
      // Maximum number of non-file fields.
      // Dropzone.js will add 6 extra fields for chunked uploads.
      // We don't use them for anything else.
      fields: 6,
      // Maximum number of file fields.
      // Chunked uploads still need to provide ONLY 1 file field.
      // Otherwise, only one of the files will end up being properly stored,
      // and that will also be as a chunk.
      files: maxFilesPerUpload
    }
  }, async field => {
    // Keep non-files fields in Request.body
    // Since fields get processed in sequence depending on the order at which they were defined,
    // chunked uploads data must be set before the files[] field which contain the actual file
    if (field.truncated) {
      // Re-map Dropzone chunked uploads keys so people can manually use the API without prepending 'dz'
      let name = field.name
      if (name.startsWith('dz')) {
        name = name.replace(/^dz/, '')
      }

      req.body[name] = field.value
      return
    }

    // Process files immediately and push into Request.files array
    if (field.file) {
      // Push immediately as we will only be adding props into the file object down the line
      const file = {
        albumid: data.albumid,
        age: data.age,
        originalname: field.file.name || '',
        mimetype: field.mime_type || '',
        isChunk: req.body.uuid !== undefined &&
          req.body.chunkindex !== undefined
      }
      req.files.push(file)

      if (file.isChunk) {
        if (!chunkedUploads) {
          throw new ClientError('Chunked uploads are disabled at the moment.')
        } else if (req.files.length > 1) {
          throw new ClientError('Chunked uploads may only be uploaded 1 chunk at a time.')
        }
      }

      file.extname = utils.extname(file.originalname)
      if (self.isExtensionFiltered(file.extname)) {
        throw new ClientError(`${file.extname ? `${file.extname.substr(1).toUpperCase()} files` : 'Files with no extension'} are not permitted.`)
      }

      if (file.isChunk) {
        // Re-map UUID property to IP-specific UUID
        const uuid = `${req.ip}_${req.body.uuid}`
        // Calling initChunks() will also reset the chunked uploads' timeout
        file.chunksData = await initChunks(uuid)
        file.filename = file.chunksData.filename
        file.path = file.chunksData.path
      } else {
        const length = self.parseFileIdentifierLength(req.headers.filelength)
        const identifier = await self.getUniqueUploadIdentifier(length, file.extname, res)
        file.filename = identifier + file.extname
        file.path = path.join(paths.uploads, file.filename)
      }

      const readStream = field.file.stream
      let writeStream
      let hashStream
      let _reject

      // Write the file into disk, and supply required props into file object
      await new Promise((resolve, reject) => {
        // Keep reference to Promise's reject function to allow unlistening events
        _reject = reject

        // Ensure this Promise's status can be asserted later
        const _resolve = () => {
          file.promised = true
          return resolve()
        }

        readStream.once('error', _reject)

        if (file.isChunk) {
          writeStream = file.chunksData.writeStream
          hashStream = file.chunksData.hashStream
        } else {
          writeStream = fs.createWriteStream(file.path)
          hashStream = enableHashing && blake3.createHash()
        }

        // Re-init stream errors listeners for this Request
        writeStream.once('error', _reject)

        if (hashStream) {
          hashStream.once('error', _reject)
          readStream.on('data', data => {
            // .dispose() will destroy this internal component,
            // so use it as an indicator of whether the hashStream has been .dispose()'d
            if (hashStream.hash.hash) {
              hashStream.update(data)
            }
          })
        }

        if (file.isChunk) {
          // We listen for readStream's end event
          readStream.once('end', () => _resolve())
        } else {
          // We immediately listen for writeStream's finish event
          writeStream.once('finish', () => {
            file.size = writeStream.bytesWritten
            if (hashStream && hashStream.hash.hash) {
              const hash = hashStream.digest('hex')
              file.hash = file.size === 0
                ? ''
                : hash
            }
            return _resolve()
          })
        }

        // Pipe readStream to writeStream
        // Do not end writeStream when readStream finishes if it's a chunk upload
        readStream
          .pipe(writeStream, { end: !file.isChunk })
      }).catch(error => {
        // Dispose of unfinished write & hasher streams
        if (writeStream && !writeStream.destroyed) {
          writeStream.destroy()
        }
        if (hashStream && hashStream.hash.hash) {
          hashStream.dispose()
        }

        // Re-throw error
        throw error
      }).finally(() => {
        if (!file.isChunk) return
        // Unlisten streams' error event for this Request if it's a chunk upload
        utils.unlistenEmitters([writeStream, hashStream], 'error', _reject)
      })

      // file.size is not populated if a chunk upload, so ignore
      if (config.filterEmptyFile && !file.isChunk && file.size === 0) {
        throw new ClientError('Empty files are not allowed.')
      }
    }
  }).catch(error => {
    // Clean up temp files and held identifiers (do not wait)
    cleanUpFiles()
    unfreezeChunksData()

    // Response.multipart() itself may throw string errors
    if (typeof error === 'string') {
      throw new ClientError(error)
    } else {
      throw error
    }
  })

  if (!req.files.length) {
    throw new ClientError('No files.')
  }

  // If for some reason Request.multipart() resolves before a file's Promise
  // Typically caused by something hanging up longer than
  // uWebSockets.js' internal security timeout (10 seconds)
  if (req.files.some(file => file.promised !== true)) {
    // Clean up temp files and held identifiers (do not wait)
    cleanUpFiles()
    unfreezeChunksData()

    throw new ServerError()
  }

  // If chunked uploads is enabled and the uploaded file is a chunk, then just say that it was a success
  // NOTE: We loop through Request.files for clarity,
  // but we will actually have already rejected the Request
  // if it has more than 1 file while being a chunk upload
  if (req.files.some(file => file.chunksData)) {
    req.files.forEach(file => {
      file.chunksData.chunks++
      // Mark as ready to accept more chunk uploads or to finalize
      file.chunksData.processing = false
    })
    return res.json({ success: true })
  }

  const filesData = req.files

  if (utils.scan.instance) {
    const scanResult = await self.scanFiles(req, filesData)
    if (scanResult) {
      throw new ClientError(scanResult)
    }
  }

  await self.stripTags(req, filesData)

  const result = await self.storeFilesToDb(req, res, filesData)
  return self.sendUploadResponse(req, res, result)
}

/** URL uploads */

self.actuallyUploadUrls = async (req, res, data = {}) => {
  if (!config.uploads.urlMaxSize) {
    throw new ClientError('Upload by URLs is disabled at the moment.', { statusCode: 403 })
  }

  const urls = req.body.urls
  if (!urls || !(urls instanceof Array)) {
    throw new ClientError('Missing "urls" property (array).')
  }

  if (urls.length > maxFilesPerUpload) {
    throw new ClientError(`Maximum ${maxFilesPerUpload} URLs at a time.`)
  }

  const assertSize = (size, isContentLength = false) => {
    if (config.filterEmptyFile && size === 0) {
      throw new ClientError('Empty files are not allowed.')
    } else if (size > urlMaxSizeBytes) {
      if (isContentLength) {
        throw new ClientError(`File too large. Content-Length header reports file is bigger than ${urlMaxSize} MB.`)
      } else {
        throw new ClientError(`File too large. File is bigger than ${urlMaxSize} MB.`)
      }
    }
  }

  const filesData = []

  await Promise.all(urls.map(async url => {
    // Push immediately as we will only be adding props into the file object down the line
    const file = {
      url,
      albumid: data.albumid,
      age: data.age
    }
    filesData.push(file)

    if (config.uploads.urlProxy) {
      url = config.uploads.urlProxy
        .replace(/{url}/g, encodeURIComponent(url))
        .replace(/{url-noprot}/g, encodeURIComponent(url.replace(/^https?:\/\//, '')))
    }

    // Try to determine size early via Content-Length header,
    // but continue anyway if it isn't a valid number
    try {
      const head = await fetch(url, { method: 'HEAD', size: urlMaxSizeBytes })
      if (head.status === 200) {
        const contentLength = parseInt(head.headers.get('content-length'))
        if (!Number.isNaN(contentLength)) {
          assertSize(contentLength, true)
        }
      }
    } catch (ex) {
      // Re-throw only if ClientError, otherwise ignore
      if (ex instanceof ClientError) {
        throw ex
      }
    }

    const length = self.parseFileIdentifierLength(req.headers.filelength)
    const identifier = await self.getUniqueUploadIdentifier(length, '.tmp', res)

    // Temporarily store to disk as a .tmp file
    file.filename = identifier + '.tmp'
    file.path = path.join(paths.uploads, file.filename)

    let writeStream
    let hashStream

    return Promise.resolve().then(async () => {
      writeStream = fs.createWriteStream(file.path)
      hashStream = enableHashing && blake3.createHash()

      // Limit max response body size with maximum allowed size
      const fetchFile = await fetch(url, { method: 'GET', size: urlMaxSizeBytes })
        .then(res => new Promise((resolve, reject) => {
          if (res.status !== 200) {
            return resolve(res)
          }

          writeStream.once('error', reject)
          res.body.once('error', reject)

          if (hashStream) {
            hashStream.once('error', reject)
            res.body.on('data', d => hashStream.update(d))
          }

          res.body.pipe(writeStream)
          writeStream.once('finish', () => resolve(res))
        }))

      if (fetchFile.status !== 200) {
        throw new ServerError(`${fetchFile.status} ${fetchFile.statusText}`)
      }

      // Re-test size via actual bytes written to physical file
      assertSize(writeStream.bytesWritten)

      // Try to determine filename from Content-Disposition header if available
      const contentDispositionHeader = fetchFile.headers.get('content-disposition')
      if (contentDispositionHeader) {
        const parsed = contentDisposition.parse(contentDispositionHeader)
        if (parsed && parsed.parameters) {
          file.originalname = parsed.parameters.filename
        }
      }

      if (!file.originalname) {
        file.originalname = path.basename(url).split(/[?#]/)[0]
      }

      file.extname = utils.extname(file.originalname)

      // Extensions filter
      let filtered = false
      if (urlExtensionsFilter && ['blacklist', 'whitelist'].includes(config.uploads.urlExtensionsFilterMode)) {
        const match = config.uploads.urlExtensionsFilter.includes(file.extname.toLowerCase())
        const whitelist = config.uploads.urlExtensionsFilterMode === 'whitelist'
        filtered = ((!whitelist && match) || (whitelist && !match))
      } else {
        filtered = self.isExtensionFiltered(file.extname)
      }

      if (filtered) {
        throw new ClientError(`${file.extname ? `${file.extname.substr(1).toUpperCase()} files` : 'Files with no extension'} are not permitted.`)
      }

      // Generate a new filename with actual extname
      // Also generate a new random identifier if required
      const _identifier = queryDatabaseForIdentifierMatch
        ? identifier
        : await self.getUniqueUploadIdentifier(length, file.extname, res)
      const _name = _identifier + file.extname

      // Move .tmp file to the new filename
      const destination = path.join(paths.uploads, _name)
      await paths.rename(file.path, destination)

      // Then update the props with renewed information
      file.filename = _name
      file.path = destination

      // Finalize other file props
      const contentType = fetchFile.headers.get('content-type')
      file.mimetype = contentType ? contentType.split(';')[0] : 'application/octet-stream'
      file.size = writeStream.bytesWritten
      file.hash = hashStream
        ? hashStream.digest('hex')
        : null
    }).catch(err => {
      // Dispose of unfinished write & hasher streams
      if (writeStream && !writeStream.destroyed) {
        writeStream.destroy()
      }
      if (hashStream && hashStream.hash.hash) {
        hashStream.dispose()
      }

      // Re-throw errors
      throw err
    })
  })).catch(async error => {
    // Unlink temp files (do not wait)
    if (filesData.length) {
      Promise.all(filesData.map(async file => {
        if (!file.filename) return
        return utils.unlinkFile(file.filename).catch(logger.error)
      }))
    }

    // Re-throw suppressed errors as ClientError, otherwise as-is
    const errorString = error.toString()
    const suppress = [
      / over limit:/
    ]
    if (suppress.some(t => t.test(errorString))) {
      throw new ClientError(errorString)
    } else {
      throw error
    }
  })

  if (utils.scan.instance) {
    const scanResult = await self.scanFiles(req, filesData)
    if (scanResult) {
      throw new ClientError(scanResult)
    }
  }

  const result = await self.storeFilesToDb(req, res, filesData)
  return self.sendUploadResponse(req, res, result)
}

/** Chunk uploads */

self.finishChunks = async (req, res) => {
  if (!chunkedUploads) {
    throw new ClientError('Chunked upload is disabled.', { statusCode: 403 })
  }

  const files = req.body.files
  if (!Array.isArray(files) || !files.length) {
    throw new ClientError('Bad request.')
  }

  // Re-map UUID property to IP-specific UUID
  files.forEach(file => {
    file.uuid = `${req.ip}_${file.uuid}`
  })

  return self.actuallyFinishChunks(req, res, files)
    .catch(error => {
      // Unlink temp files (do not wait)
      Promise.all(files.map(async file => {
        if (file.uuid && chunksData[file.uuid]) {
          return self.cleanUpChunks(file.uuid).catch(logger.error)
        }
      }))
      // Re-throw errors
      throw error
    })
}

self.actuallyFinishChunks = async (req, res, files) => {
  const filesData = []
  await Promise.all(files.map(async file => {
    if (!file.uuid || typeof chunksData[file.uuid] === 'undefined') {
      throw new ClientError('Invalid file UUID, or chunks data had already timed out. Try again?')
    }

    if (chunksData[file.uuid].processing) {
      throw new ClientError('Previous chunk upload is still being processed. Try again?')
    }

    // Suspend timeout
    // If the chunk errors out there, it will be immediately cleaned up anyway
    chunksData[file.uuid].clearTimeout()

    // Conclude write and hasher streams
    chunksData[file.uuid].writeStream.end()
    const bytesWritten = chunksData[file.uuid].writeStream.bytesWritten
    const hash = chunksData[file.uuid].hashStream
      ? chunksData[file.uuid].hashStream.digest('hex')
      : null

    if (chunksData[file.uuid].chunks < 2 || chunksData[file.uuid].chunks > maxChunksCount) {
      throw new ClientError('Invalid chunks count.')
    }

    const extname = typeof file.original === 'string' ? utils.extname(file.original) : ''
    if (self.isExtensionFiltered(extname)) {
      throw new ClientError(`${extname ? `${extname.substr(1).toUpperCase()} files` : 'Files with no extension'} are not permitted.`)
    }

    const age = self.assertRetentionPeriod(req.locals.user, file.age)

    let size = file.size
    if (size === undefined) {
      size = bytesWritten
    } else if (size !== bytesWritten) {
      // If client reports actual total size, confirm match
      throw new ClientError(`Written bytes (${bytesWritten}) does not match actual size reported by client (${size}).`)
    }

    if (config.filterEmptyFile && size === 0) {
      throw new ClientError('Empty files are not allowed.')
    } else if (size > maxSizeBytes) {
      throw new ClientError(`File too large. Chunks are bigger than ${maxSize} MB.`)
    }

    const tmpfile = path.join(chunksData[file.uuid].root, chunksData[file.uuid].filename)

    // Double-check file size
    const lstat = await paths.lstat(tmpfile)
    if (lstat.size !== size) {
      throw new ClientError(`Resulting physical file size (${lstat.size}) does not match expected size (${size}).`)
    }

    // Generate name
    const length = self.parseFileIdentifierLength(file.filelength)
    const identifier = await self.getUniqueUploadIdentifier(length, extname, res)
    const name = identifier + extname

    // Move tmp file to final destination
    // For fs.copyFile(), tmpfile will eventually be unlinked by self.cleanUpChunks()
    const destination = path.join(paths.uploads, name)
    if (chunksCopyFile) {
      await paths.copyFile(tmpfile, destination)
    } else {
      await paths.rename(tmpfile, destination)
    }

    // Continue even when encountering errors
    await self.cleanUpChunks(file.uuid).catch(logger.error)

    let albumid = parseInt(file.albumid)
    if (isNaN(albumid)) {
      albumid = null
    }

    filesData.push({
      filename: name,
      originalname: file.original || '',
      extname,
      mimetype: file.type || '',
      path: destination,
      size,
      hash,
      albumid,
      age
    })
  }))

  if (utils.scan.instance) {
    const scanResult = await self.scanFiles(req, filesData)
    if (scanResult) {
      throw new ClientError(scanResult)
    }
  }

  await self.stripTags(req, filesData)

  const result = await self.storeFilesToDb(req, res, filesData)
  return self.sendUploadResponse(req, res, result)
}

self.cleanUpChunks = async uuid => {
  // Dispose of unfinished write & hasher streams
  if (chunksData[uuid].writeStream && !chunksData[uuid].writeStream.destroyed) {
    chunksData[uuid].writeStream.destroy()
  }
  if (chunksData[uuid].hashStream && chunksData[uuid].hashStream.hash.hash) {
    chunksData[uuid].hashStream.dispose()
  }

  // Remove tmp file
  await paths.unlink(path.join(chunksData[uuid].root, chunksData[uuid].filename))
    .catch(error => {
      // Re-throw non-ENOENT error
      if (error.code !== 'ENOENT') logger.error(error)
    })

  // Remove UUID dir
  await paths.rmdir(chunksData[uuid].root)

  // Delete cached chunks data
  delete chunksData[uuid]
}

/** Virus scanning (ClamAV) */

self.assertScanUserBypass = (user, filenames) => {
  if (!user || !utils.scan.groupBypass) {
    return false
  }

  if (!Array.isArray(filenames)) {
    filenames = [filenames]
  }

  logger.debug(`[ClamAV]: ${filenames.join(', ')}: Skipped, uploaded by ${user.username} (${utils.scan.groupBypass})`)
  return perms.is(user, utils.scan.groupBypass)
}

self.assertScanFileBypass = data => {
  if (typeof data !== 'object' || !data.filename) {
    return false
  }

  const extname = data.extname || utils.extname(data.filename)
  if (utils.scan.whitelistExtensions && utils.scan.whitelistExtensions.includes(extname)) {
    logger.debug(`[ClamAV]: ${data.filename}: Skipped, extension whitelisted`)
    return true
  }

  if (utils.scan.maxSize && data.size !== undefined && data.size > utils.scan.maxSize) {
    logger.debug(`[ClamAV]: ${data.filename}: Skipped, size ${data.size} > ${utils.scan.maxSize}`)
    return true
  }

  return false
}

self.scanFiles = async (req, filesData) => {
  const filenames = filesData.map(file => file.filename)
  if (self.assertScanUserBypass(req.locals.user, filenames)) {
    return false
  }

  const foundThreats = []
  const unableToScan = []
  const result = await Promise.all(filesData.map(async file => {
    if (self.assertScanFileBypass(file)) return

    logger.debug(`[ClamAV]: ${file.filename}: Scanning\u2026`)
    const response = await utils.scan.instance.isInfected(file.path)
    if (response.isInfected) {
      logger.log(`[ClamAV]: ${file.filename}: ${response.viruses.join(', ')}`)
      foundThreats.push(...response.viruses)
    } else if (response.isInfected === null) {
      logger.log(`[ClamAV]: ${file.filename}: Unable to scan`)
      unableToScan.push(file.filename)
    } else {
      logger.debug(`[ClamAV]: ${file.filename}: File is clean`)
    }
  })).then(() => {
    if (foundThreats.length) {
      const more = foundThreats.length > 1
      return `Threat${more ? 's' : ''} detected: ${foundThreats[0]}${more ? ', and more' : ''}.`
    } else if (unableToScan.length) {
      const more = unableToScan.length > 1
      return `Unable to scan: ${unableToScan[0]}${more ? ', and more' : ''}.`
    }
  }).catch(error => {
    logger.error(`[ClamAV]: ${filenames.join(', ')}: ${error.toString()}`)
    return 'An unexpected error occurred with ClamAV, please contact the site owner.'
  })

  if (result) {
    // Unlink temp files (do not wait)
    Promise.all(filesData.map(async file =>
      utils.unlinkFile(file.filename).catch(logger.error)
    ))
  }

  return result
}

/** Strip tags (EXIF, etc.) */

self.stripTags = async (req, filesData) => {
  if (!self.parseStripTags(req.headers.striptags)) return

  try {
    await Promise.all(filesData.map(async file =>
      utils.stripTags(file.filename, file.extname)
    ))
  } catch (error) {
    // Unlink temp files (do not wait)
    Promise.all(filesData.map(async file =>
      utils.unlinkFile(file.filename).catch(logger.error)
    ))

    // Re-throw error
    throw error
  }
}

/** Database functions */

self.storeFilesToDb = async (req, res, filesData) => {
  const files = []
  const exists = []
  const albumids = []

  await Promise.all(filesData.map(async file => {
    if (enableHashing) {
      // Check if the file exists by checking its hash and size
      const dbFile = await utils.db.table('files')
        .where(function () {
          if (req.locals.user) {
            this.where('userid', req.locals.user.id)
          } else {
            this.whereNull('userid')
          }
        })
        .where({
          hash: file.hash,
          size: String(file.size)
        })
        // Select expirydate to display expiration date of existing files as well
        .select('name', 'expirydate')
        .first()

      if (dbFile) {
        // Continue even when encountering errors
        await utils.unlinkFile(file.filename).catch(logger.error)
        logger.debug(`Unlinked ${file.filename} since a duplicate named ${dbFile.name} exists`)

        // If on /nojs route, append original name reported by client,
        // instead of the actual original name from database
        if (req.path === '/nojs') {
          dbFile.original = file.originalname
        }

        exists.push(dbFile)
        return
      }
    }

    const timestamp = Math.floor(Date.now() / 1000)
    const data = {
      name: file.filename,
      original: file.originalname,
      type: file.mimetype,
      size: String(file.size),
      hash: file.hash,
      // Only disable if explicitly set to false in config
      ip: config.uploads.storeIP !== false ? req.ip : null,
      timestamp
    }

    if (req.locals.user) {
      data.userid = req.locals.user.id
      data.albumid = file.albumid
      if (data.albumid !== null && !albumids.includes(data.albumid)) {
        albumids.push(data.albumid)
      }
    }

    if (file.age) {
      data.expirydate = data.timestamp + (file.age * 3600) // Hours to seconds
    }

    files.push(data)

    // Generate thumbs, but do not wait
    if (utils.mayGenerateThumb(file.extname)) {
      utils.generateThumbs(file.filename, file.extname, true).catch(logger.error)
    }
  }))

  if (files.length) {
    // albumids should be empty if non-registerd users (no auth requests)
    let authorizedIds = []
    if (albumids.length) {
      authorizedIds = await utils.db.table('albums')
        .where({ userid: req.locals.user.id })
        .whereIn('id', albumids)
        .select('id')
        .then(rows => rows.map(row => row.id))

      // Remove albumid if user do not own the album
      for (const file of files) {
        if (file.albumid !== null && !authorizedIds.includes(file.albumid)) {
          file.albumid = null
        }
      }
    }

    await utils.db.transaction(async trx => {
      // Insert new files to DB
      await trx('files')
        .insert(files)
      utils.invalidateStatsCache('uploads')

      // Update albums' timestamp
      if (authorizedIds.length) {
        await trx('albums')
          .whereIn('id', authorizedIds)
          .update('editedAt', Math.floor(Date.now() / 1000))
        utils.deleteStoredAlbumRenders(authorizedIds)
      }
    })
  }

  return [...files, ...exists]
}

/** Final response */

self.sendUploadResponse = async (req, res, result) => {
  // Send response
  return res.json({
    success: true,
    files: result.map(file => {
      const map = {
        name: file.name,
        url: `${utils.conf.domain ? `${utils.conf.domain}/` : ''}${file.name}`
      }

      // If a temporary upload, add expiry date
      if (file.expirydate) {
        map.expirydate = file.expirydate
      }

      // If on /nojs route, add original name
      if (req.path === '/nojs') {
        map.original = file.original
      }

      // If uploaded by user, add delete URL (intended for ShareX and its derivatives)
      // Homepage uploader will not use this (use dashboard instead)
      if (req.locals.user) {
        map.deleteUrl = `${utils.conf.homeDomain}/file/${file.name}?delete`
      }

      return map
    })
  })
}

/** Delete uploads */

self.delete = async (req, res) => {
  // Re-map Request.body for .bulkDelete()
  // This is the legacy API used by lolisafe v3's frontend
  // Meanwhile this fork's frontend uses .bulkDelete() straight away
  const id = parseInt(req.body.id)
  req.body = {
    _legacy: true,
    field: 'id',
    values: isNaN(id) ? undefined : [id]
  }

  return self.bulkDelete(req, res)
}

self.bulkDelete = async (req, res) => {
  const field = req.body.field || 'id'
  const values = req.body.values

  if (!Array.isArray(values) || !values.length) {
    throw new ClientError('No array of files specified.')
  }

  const failed = await utils.bulkDeleteFromDb(field, values, req.locals.user)

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

/** List uploads */

self.list = async (req, res) => {
  const all = req.headers.all === '1'
  const filters = req.headers.filters
  const minoffset = Number(req.headers.minoffset) || 0
  const ismoderator = perms.is(req.locals.user, 'moderator')
  if (all && !ismoderator) {
    return res.status(403).end()
  }

  const albumid = req.path_parameters && Number(req.path_parameters.albumid)
  const basedomain = utils.conf.domain

  // Thresholds for regular users (usergroups lower than moderator)
  const MAX_WILDCARDS_IN_KEY = 2
  const MAX_TEXT_QUERIES = 3 // non-keyed keywords
  const MAX_SORT_KEYS = 2
  const MAX_IS_KEYS = 1

  const filterObj = {
    uploaders: [],
    excludeUploaders: [],
    queries: {
      exclude: {}
    },
    typeIs: [
      'image',
      'video',
      'audio'
    ],
    flags: {}
  }

  const sortObj = {
    // Cast columns to specific type if they are stored differently
    casts: {
      size: 'integer'
    },
    // Columns mapping
    maps: {
      date: 'timestamp',
      expiry: 'expirydate',
      originalname: 'original'
    },
    // Columns with which to use SQLite's NULLS LAST option
    nullsLast: [
      'userid',
      'albumid',
      'expirydate',
      'ip'
    ],
    parsed: []
  }

  // Parse glob wildcards into SQL wildcards
  function sqlLikeParser (pattern) {
    // Escape SQL operators
    const escaped = pattern
      .replace(/(?<!\\)%/g, '\\%')
      .replace(/(?<!\\)_/g, '\\_')

    // Look for any glob operators
    const match = pattern.match(/(?<!\\)(\*|\?)/g)
    if (match && match.length) {
      return {
        count: match.length,
        // Replace glob operators with their SQL equivalents
        escaped: escaped
          .replace(/(?<!\\)\*/g, '%')
          .replace(/(?<!\\)\?/g, '_')
      }
    } else {
      return {
        count: 0,
        // Assume partial match
        escaped: `%${escaped}%`
      }
    }
  }

  if (filters) {
    const keywords = []

    // Only allow filtering by 'albumid' when not listing a specific album's uploads
    if (isNaN(albumid)) {
      keywords.push('albumid')
    }

    // Only allow filtering by 'ip' and 'user' keys when listing all uploads
    if (all) {
      keywords.push('ip', 'user')
    }

    const ranges = [
      'date',
      'expiry'
    ]

    keywords.push('is', 'sort', 'orderby')
    filterObj.queries = searchQuery.parse(filters, {
      keywords,
      ranges,
      tokenize: true,
      alwaysArray: true,
      offsets: false
    })

    // Accept orderby as alternative for sort
    if (filterObj.queries.orderby) {
      if (!filterObj.queries.sort) filterObj.queries.sort = []
      filterObj.queries.sort.push(...filterObj.queries.orderby)
      delete filterObj.queries.orderby
    }

    // For some reason, single value won't be in Array even with 'alwaysArray' option
    if (typeof filterObj.queries.exclude.text === 'string') {
      filterObj.queries.exclude.text = [filterObj.queries.exclude.text]
    }

    // Text (non-keyed keywords) queries
    let textQueries = 0
    if (filterObj.queries.text) textQueries += filterObj.queries.text.length
    if (filterObj.queries.exclude.text) textQueries += filterObj.queries.exclude.text.length

    // Regular user threshold check
    if (!ismoderator && textQueries > MAX_TEXT_QUERIES) {
      throw new ClientError(`Users are only allowed to use ${MAX_TEXT_QUERIES} non-keyed keyword${MAX_TEXT_QUERIES === 1 ? '' : 's'} at a time.`)
    }

    if (filterObj.queries.text) {
      for (let i = 0; i < filterObj.queries.text.length; i++) {
        const result = sqlLikeParser(filterObj.queries.text[i])
        if (!ismoderator && result.count > MAX_WILDCARDS_IN_KEY) {
          throw new ClientError(`Users are only allowed to use ${MAX_WILDCARDS_IN_KEY} wildcard${MAX_WILDCARDS_IN_KEY === 1 ? '' : 's'} per key.`)
        }
        filterObj.queries.text[i] = result.escaped
      }
    }

    if (filterObj.queries.exclude.text) {
      for (let i = 0; i < filterObj.queries.exclude.text.length; i++) {
        const result = sqlLikeParser(filterObj.queries.exclude.text[i])
        if (!ismoderator && result.count > MAX_WILDCARDS_IN_KEY) {
          throw new ClientError(`Users are only allowed to use ${MAX_WILDCARDS_IN_KEY} wildcard${MAX_WILDCARDS_IN_KEY === 1 ? '' : 's'} per key.`)
        }
        filterObj.queries.exclude.text[i] = result.escaped
      }
    }

    for (const key of keywords) {
      let queryIndex = -1
      let excludeIndex = -1

      // Make sure keyword arrays only contain unique values
      if (filterObj.queries[key]) {
        filterObj.queries[key] = filterObj.queries[key].filter((v, i, a) => a.indexOf(v) === i)
        queryIndex = filterObj.queries[key].indexOf('-')
      }
      if (filterObj.queries.exclude[key]) {
        filterObj.queries.exclude[key] = filterObj.queries.exclude[key].filter((v, i, a) => a.indexOf(v) === i)
        excludeIndex = filterObj.queries.exclude[key].indexOf('-')
      }

      // Flag to match NULL values
      const inQuery = queryIndex !== -1
      const inExclude = excludeIndex !== -1
      if (inQuery || inExclude) {
        // Prioritize exclude keys when both types found
        filterObj.flags[`${key}Null`] = inExclude ? false : inQuery
        if (inQuery) {
          if (filterObj.queries[key].length === 1) {
            // Delete key to avoid unexpected behavior
            delete filterObj.queries[key]
          } else {
            filterObj.queries[key].splice(queryIndex, 1)
          }
        }
        if (inExclude) {
          if (filterObj.queries.exclude[key].length === 1) {
            // Delete key to avoid unexpected behavior
            delete filterObj.queries.exclude[key]
          } else {
            filterObj.queries.exclude[key].splice(excludeIndex, 1)
          }
        }
      }
    }

    const parseDate = (date, minoffset, resetMs) => {
      // [YYYY][/MM][/DD] [HH][:MM][:SS]
      // e.g. 2020/01/01 00:00:00, 2018/01/01 06, 2019/11, 12:34:00
      const match = date.match(/^(\d{4})?(\/\d{2})?(\/\d{2})?\s?(\d{2})?(:\d{2})?(:\d{2})?$/)

      if (match) {
        let offset = 0
        if (minoffset !== undefined) {
          offset = 60000 * (utils.timezoneOffset - minoffset)
        }

        const dateObj = new Date(Date.now() + offset)

        if (match[1] !== undefined) {
          dateObj.setFullYear(Number(match[1]), // full year
            match[2] !== undefined ? (Number(match[2].slice(1)) - 1) : 0, // month, zero-based
            match[3] !== undefined ? Number(match[3].slice(1)) : 1) // date
        }

        if (match[4] !== undefined) {
          dateObj.setHours(Number(match[4]), // hours
            match[5] !== undefined ? Number(match[5].slice(1)) : 0, // minutes
            match[6] !== undefined ? Number(match[6].slice(1)) : 0) // seconds
        }

        if (resetMs) {
          dateObj.setMilliseconds(0)
        }

        // Calculate timezone differences
        return new Date(dateObj.getTime() - offset)
      } else {
        return null
      }
    }

    // Parse dates to timestamps
    for (const range of ranges) {
      if (filterObj.queries[range]) {
        if (filterObj.queries[range].from) {
          const parsed = parseDate(filterObj.queries[range].from, minoffset, true)
          filterObj.queries[range].from = parsed ? Math.floor(parsed / 1000) : null
        }
        if (filterObj.queries[range].to) {
          const parsed = parseDate(filterObj.queries[range].to, minoffset, true)
          filterObj.queries[range].to = parsed ? Math.ceil(parsed / 1000) : null
        }
      }
    }

    // Query users table for user IDs
    if (filterObj.queries.user || filterObj.queries.exclude.user) {
      const usernames = []
      if (filterObj.queries.user) {
        usernames.push(...filterObj.queries.user)
      }
      if (filterObj.queries.exclude.user) {
        usernames.push(...filterObj.queries.exclude.user)
      }

      const uploaders = await utils.db.table('users')
        .whereIn('username', usernames)
        .select('id', 'username')

      // If no matches, or mismatched results
      if (!uploaders || (uploaders.length !== usernames.length)) {
        const notFound = usernames.filter(username => {
          return !uploaders.find(uploader => uploader.username === username)
        })
        if (notFound) {
          throw new ClientError(`User${notFound.length === 1 ? '' : 's'} not found: ${notFound.join(', ')}.`)
        }
      }

      for (const uploader of uploaders) {
        if (filterObj.queries.user && filterObj.queries.user.includes(uploader.username)) {
          filterObj.uploaders.push(uploader)
        } else {
          filterObj.excludeUploaders.push(uploader)
        }
      }

      // Delete keys to avoid unexpected behavior
      delete filterObj.queries.user
      delete filterObj.queries.exclude.user
    }

    // Parse sort keys
    if (filterObj.queries.sort) {
      const allowed = [
        'expirydate',
        'id',
        'name',
        'original',
        'size',
        'timestamp'
      ]

      // Only allow sorting by 'albumid' when not listing a specific album's uploads
      if (isNaN(albumid)) {
        allowed.push('albumid')
      }

      // Only allow sorting by 'ip' and 'userid' columns when listing all uploads
      if (all) {
        allowed.push('ip', 'userid')
      }

      for (const obQuery of filterObj.queries.sort) {
        const tmp = obQuery.toLowerCase().split(':')
        const column = sortObj.maps[tmp[0]] || tmp[0]

        if (!allowed.includes(column)) {
          // Alert users if using disallowed/missing columns
          throw new ClientError(`Column "${column}" cannot be used for sorting.\n\nTry the following instead:\n${allowed.join(', ')}`)
        }

        sortObj.parsed.push({
          column,
          order: (tmp[1] && /^d/.test(tmp[1])) ? 'desc' : 'asc',
          clause: sortObj.nullsLast.includes(column) ? 'nulls last' : '',
          cast: sortObj.casts[column] || null
        })
      }

      // Regular user threshold check
      if (!ismoderator && sortObj.parsed.length > MAX_SORT_KEYS) {
        throw new ClientError(`Users are only allowed to use ${MAX_SORT_KEYS} sort key${MAX_SORT_KEYS === 1 ? '' : 's'} at a time.`)
      }

      // Delete key to avoid unexpected behavior
      delete filterObj.queries.sort
    }

    // Parse is keys
    let isKeys = 0
    let isLast
    if (filterObj.queries.is || filterObj.queries.exclude.is) {
      for (const type of filterObj.typeIs) {
        const inQuery = filterObj.queries.is && filterObj.queries.is.includes(type)
        const inExclude = filterObj.queries.exclude.is && filterObj.queries.exclude.is.includes(type)

        // Prioritize exclude keys when both types found
        if (inQuery || inExclude) {
          filterObj.flags[`is${type}`] = inExclude ? false : inQuery
          if (isLast !== undefined && isLast !== filterObj.flags[`is${type}`]) {
            throw new ClientError('Cannot mix inclusion and exclusion type-is keys.')
          }
          isKeys++
          isLast = filterObj.flags[`is${type}`]
        }
      }

      // Delete keys to avoid unexpected behavior
      delete filterObj.queries.is
      delete filterObj.queries.exclude.is
    }

    // Regular user threshold check
    if (!ismoderator && isKeys > MAX_IS_KEYS) {
      throw new ClientError(`Users are only allowed to use ${MAX_IS_KEYS} type-is key${MAX_IS_KEYS === 1 ? '' : 's'} at a time.`)
    }
  }

  function filter () {
    // If listing all uploads
    if (all) {
      this.where(function () {
        // Filter uploads matching any of the supplied 'user' keys and/or NULL flag
        // Prioritze exclude keys when both types found
        this.orWhere(function () {
          if (filterObj.excludeUploaders.length) {
            this.whereNotIn('userid', filterObj.excludeUploaders.map(v => v.id))
          } else if (filterObj.uploaders.length) {
            this.orWhereIn('userid', filterObj.uploaders.map(v => v.id))
          }
          // Such overbearing logic for NULL values, smh...
          if ((filterObj.excludeUploaders.length && filterObj.flags.userNull !== false) ||
            (filterObj.uploaders.length && filterObj.flags.userNull) ||
            (!filterObj.excludeUploaders.length && !filterObj.uploaders.length && filterObj.flags.userNull)) {
            this.orWhereNull('userid')
          } else if (filterObj.flags.userNull === false) {
            this.whereNotNull('userid')
          }
        })

        // Filter uploads matching any of the supplied 'ip' keys and/or NULL flag
        // Same prioritization logic as above
        this.orWhere(function () {
          if (filterObj.queries.exclude.ip) {
            this.whereNotIn('ip', filterObj.queries.exclude.ip)
          } else if (filterObj.queries.ip) {
            this.orWhereIn('ip', filterObj.queries.ip)
          }
          // ...
          if ((filterObj.queries.exclude.ip && filterObj.flags.ipNull !== false) ||
            (filterObj.queries.ip && filterObj.flags.ipNull) ||
            (!filterObj.queries.exclude.ip && !filterObj.queries.ip && filterObj.flags.ipNull)) {
            this.orWhereNull('ip')
          } else if (filterObj.flags.ipNull === false) {
            this.whereNotNull('ip')
          }
        })
      })
    } else {
      // If not listing all uploads, list user's uploads
      this.where('userid', req.locals.user.id)
    }

    // Then, refine using any of the supplied 'albumid' keys and/or NULL flag
    // Same prioritization logic as 'userid' and 'ip' above
    if (isNaN(albumid)) {
      this.andWhere(function () {
        if (filterObj.queries.exclude.albumid) {
          this.whereNotIn('albumid', filterObj.queries.exclude.albumid)
        } else if (filterObj.queries.albumid) {
          this.orWhereIn('albumid', filterObj.queries.albumid)
        }
        // ...
        if ((filterObj.queries.exclude.albumid && filterObj.flags.albumidNull !== false) ||
          (filterObj.queries.albumid && filterObj.flags.albumidNull) ||
          (!filterObj.queries.exclude.albumid && !filterObj.queries.albumid && filterObj.flags.albumidNull)) {
          this.orWhereNull('albumid')
        } else if (filterObj.flags.albumidNull === false) {
          this.whereNotNull('albumid')
        }
      })
    } else if (!all) {
      // If not listing all uploads, list uploads from user's album
      this.andWhere('albumid', req.path_parameters.albumid)
    }

    // Then, refine using the supplied 'date' ranges
    this.andWhere(function () {
      if (!filterObj.queries.date ||
        (!filterObj.queries.date.from && !filterObj.queries.date.to)) {
        return
      }
      if (typeof filterObj.queries.date.from === 'number') {
        if (typeof filterObj.queries.date.to === 'number') {
          this.andWhereBetween('timestamp', [filterObj.queries.date.from, filterObj.queries.date.to])
        } else {
          this.andWhere('timestamp', '>=', filterObj.queries.date.from)
        }
      } else {
        this.andWhere('timestamp', '<=', filterObj.queries.date.to)
      }
    })

    // Then, refine using the supplied 'expiry' ranges
    this.andWhere(function () {
      if (!filterObj.queries.expiry ||
        (!filterObj.queries.expiry.from && !filterObj.queries.expiry.to)) {
        return
      }
      if (typeof filterObj.queries.expiry.from === 'number') {
        if (typeof filterObj.queries.expiry.to === 'number') {
          this.andWhereBetween('expirydate', [filterObj.queries.expiry.from, filterObj.queries.expiry.to])
        } else {
          this.andWhere('expirydate', '>=', filterObj.queries.expiry.from)
        }
      } else {
        this.andWhere('expirydate', '<=', filterObj.queries.expiry.to)
      }
    })

    // Then, refine using type-is flags
    this.andWhere(function () {
      for (const type of filterObj.typeIs) {
        let func
        let operator
        if (filterObj.flags[`is${type}`] === true) {
          func = 'orWhere'
          operator = 'like'
        } else if (filterObj.flags[`is${type}`] === false) {
          func = 'andWhere'
          operator = 'not like'
        }

        if (func) {
          for (const pattern of utils[`${type}Exts`].map(ext => `%${ext}`)) {
            this[func]('name', operator, pattern)
          }
        }
      }
    })

    // Then, refine using the supplied keywords against their file names
    this.andWhere(function () {
      if (!filterObj.queries.text) return
      for (const pattern of filterObj.queries.text) {
        this.orWhereRaw('?? like ? escape ?', ['name', pattern, '\\'])
        this.orWhereRaw('?? like ? escape ?', ['original', pattern, '\\'])
      }
    })

    // Finally, refine using the supplied exclusions against their file names
    this.andWhere(function () {
      if (!filterObj.queries.exclude.text) return
      for (const pattern of filterObj.queries.exclude.text) {
        this.andWhereRaw('?? not like ? escape ?', ['name', pattern, '\\'])
        this.andWhereRaw('?? not like ? escape ?', ['original', pattern, '\\'])
      }
    })
  }

  // Base result object
  const result = { success: true, files: [], uploadsPerPage, count: 0, basedomain }

  // Query uploads count for pagination
  result.count = await utils.db.table('files')
    .where(filter)
    .count('id as count')
    .then(rows => rows[0].count)
  if (!result.count) {
    return res.json(result)
  }

  let offset = req.path_parameters && Number(req.path_parameters.page)
  if (isNaN(offset)) {
    offset = 0
  } else if (offset < 0) {
    offset = Math.max(0, Math.ceil(result.count / uploadsPerPage) + offset)
  }

  // Database columns to query
  const columns = ['id', 'name', 'original', 'userid', 'size', 'timestamp']

  if (utils.retentions.enabled) {
    columns.push('expirydate')
  }

  const filterByAlbums = filterObj.queries.albumid ||
    filterObj.queries.exclude.albumid ||
    filterObj.flags.albumidNull !== undefined

  // If not listing all uploads, OR specifically filtering by album IDs
  if (!all || filterByAlbums) {
    columns.push('albumid')
  }

  // Only select IPs if we are listing all uploads
  if (all) {
    columns.push('ip')
  }

  // Build raw query for order by (sorting) operation
  let orderByRaw
  if (sortObj.parsed.length) {
    orderByRaw = sortObj.parsed.map(sort => {
      // Use Knex.raw() to sanitize user inputs
      if (sort.cast) {
        return utils.db.raw(`cast (?? as ${sort.cast}) ${sort.order} ${sort.clause}`.trim(), sort.column)
      } else {
        return utils.db.raw(`?? ${sort.order} ${sort.clause}`.trim(), sort.column)
      }
    }).join(', ')
  } else {
    orderByRaw = '`id` desc'
  }

  result.files = await utils.db.table('files')
    .where(filter)
    .orderByRaw(orderByRaw)
    .limit(uploadsPerPage)
    .offset(uploadsPerPage * offset)
    .select(columns)

  if (!result.files.length) {
    return res.json(result)
  }

  for (const file of result.files) {
    file.extname = utils.extname(file.name)
    if (utils.mayGenerateThumb(file.extname)) {
      file.thumb = `thumbs/${file.name.slice(0, -file.extname.length)}.png`
    }
  }

  result.albums = {}

  // If not listing all uploads, OR specifically filtering by album IDs
  if (!all || filterByAlbums) {
    const albumids = result.files
      .map(file => file.albumid)
      .filter(utils.filterUniquifySqlArray)

    result.albums = await utils.db.table('albums')
      .where(function () {
        this.whereIn('id', albumids)

        // Only include data of disabled albums if listing all uploads
        // and filtering by album IDs
        if (!all) {
          this.andWhere('enabled', 1)
        }
      })
      .select('id', 'name', 'enabled')
      .then(rows => {
        // Build Object indexed by their IDs
        const obj = {}
        for (const row of rows) {
          obj[row.id] = row.name
        }
        return obj
      })

    // If filtering by album IDs,
    // then filter out uploads with missing albums data (assume disabled/deleted)
    if (filterByAlbums) {
      result.files = result.files.filter(file => result.albums[file.albumid] !== undefined)
    }
  }

  // If we are not listing all uploads, send response
  if (!all) {
    return res.json(result)
  }

  // Otherwise proceed to querying usernames
  let usersTable = filterObj.uploaders
  if (!usersTable.length) {
    const userids = result.files
      .map(file => file.userid)
      .filter(utils.filterUniquifySqlArray)

    // If there are no uploads attached to a registered user, send response
    if (!userids.length) {
      return res.json(result)
    }

    // Query usernames of user IDs from currently selected files
    usersTable = await utils.db.table('users')
      .whereIn('id', userids)
      .select('id', 'username')
  }

  result.users = {}

  for (const user of usersTable) {
    result.users[user.id] = user.username
  }

  return res.json(result)
}

/** Get file info */

self.get = async (req, res) => {
  const ismoderator = perms.is(req.locals.user, 'moderator')

  const identifier = req.path_parameters && req.path_parameters.identifier
  if (identifier === undefined) {
    throw new ClientError('No identifier provided.')
  }

  const file = await utils.db.table('files')
    .where('name', identifier)
    .where(function () {
      // Only allow moderators to get any files' information
      if (!ismoderator) {
        this.where('userid', req.locals.user.id)
      }
    })
    .first()

  if (!file) {
    throw new ClientError('File not found.', { statusCode: 404 })
  }

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

module.exports = self