file-box.ts

/**
 * File Box
 * https://github.com/huan/file-box
 *
 * 2018 Huan LI <zixia@zixia.net>
 */
/* eslint no-use-before-define: off */

import * as FS        from 'fs'
import type * as HTTP from 'http'
import * as PATH      from 'path'
import * as URL       from 'url'

import mime           from 'mime'

import {
  PassThrough,
  Readable,
  Writable,
}                         from 'stream'
import {
  instanceToClass,
  looseInstanceOfClass,
  interfaceOfClass,
}                         from 'clone-class'

import {
  VERSION,
}                         from './config.js'
import {
  FileBoxJsonObject,
  FileBoxOptions,
  FileBoxOptionsBase64,
  FileBoxOptionsCommon,
  FileBoxOptionsQRCode,
  FileBoxOptionsUrl,
  FileBoxOptionsUuid,
  FileBoxType,
  Metadata,
  Pipeable,
  UuidLoader,
  UuidSaver,
}                         from './file-box.type.js'
import {
  dataUrlToBase64,
  httpHeaderToFileName,
  httpHeadHeader,
  httpStream,
  streamToBuffer,
}                         from './misc.js'
import {
  bufferToQrValue,
  qrValueToStream,
}                         from './qrcode.js'
import {
  sizedChunkTransformer,
}                         from './pure-functions/sized-chunk-transformer.js'
import type {
  FileBoxInterface,
}                         from './interface.js'

const EMPTY_META_DATA = Object.freeze({})
const UNKNOWN_SIZE    = -1

let interfaceOfFileBox      = (_: any): _ is FileBoxInterface => false
let looseInstanceOfFileBox  = (_: any): _ is FileBox          => false

class FileBox implements Pipeable, FileBoxInterface {

  /**
   *
   * Static Properties
   *
   */
  static readonly version = VERSION

  /**
   * Symbol.hasInstance: instanceof
   *
   * @link https://www.keithcirkel.co.uk/metaprogramming-in-es6-symbols/
   */
  static [Symbol.hasInstance] (lho: any): lho is FileBoxInterface {
    return this.validInterface(lho)
  }

  /**
   * Check if obj satisfy FileBox interface
   */
  static valid (target: any): target is FileBoxInterface {
    return this.validInstance(target) || this.validInterface(target)
  }

  /**
   * Check if obj satisfy FileBox interface
   */
  static validInterface (target: any): target is FileBoxInterface {
    return interfaceOfFileBox(target)
  }

  /**
   * loose check instance of FileBox
   */
  static validInstance (target: any): target is FileBox {
    return looseInstanceOfFileBox(target)
  }

  static fromUrl (
    url      : string,
    options? : {
      headers? : HTTP.OutgoingHttpHeaders,
      name?    : string,
      size?    : number,
      md5?     : string,
    },
  ): FileBox

  /**
   * @deprecated use `fromUrl(url, options)` instead
   */
  static fromUrl (
    url      : string,
    name?    : string,
    headers? : HTTP.OutgoingHttpHeaders,
  ): FileBox

  /**
   * fromUrl()
   */
  static fromUrl (
    url            : string,
    nameOrOptions? : string | {
      headers? : HTTP.OutgoingHttpHeaders,
      name?    : string,
      size?    : number,
      md5?     : string,
    },
    headers? : HTTP.OutgoingHttpHeaders,
  ): FileBox {
    let name: undefined | string
    let size: undefined | number
    let md5: undefined | string

    if (typeof nameOrOptions === 'object') {
      headers = nameOrOptions.headers
      name    = nameOrOptions.name
      size    = nameOrOptions.size
      md5     = nameOrOptions.md5
    } else {
      name = nameOrOptions
    }

    if (!name) {
      const parsedUrl = new URL.URL(url)
      name = parsedUrl.pathname
    }
    const options: FileBoxOptions = {
      headers,
      md5,
      name,
      size,
      type : FileBoxType.Url,
      url,
    }
    return new this(options)
  }

  /**
   * Alias for `FileBox.fromFile()`
   *
   * @alias fromFile
   */

  static fromFile (
    path:   string,
    name?:  string,
    md5?:    string,
  ): FileBox {
    if (!name) {
      name = PATH.parse(path).base
    }
    const options: FileBoxOptions = {
      md5,
      name,
      path,
      type : FileBoxType.File,
    }

    return new this(options)
  }

  /**
   * TODO: add `FileBoxStreamOptions` with `size` support (@huan, 202111)
   */
  static fromStream (
    stream: Readable,
    name?:  string,
    md5?:   string,
  ): FileBox {
    const options: FileBoxOptions = {
      md5,
      name: name || 'stream.dat',
      stream,
      type: FileBoxType.Stream,
    }
    return new this(options)
  }

  static fromBuffer (
    buffer: Buffer,
    name?:   string,
    md5?:    string,
  ): FileBox {
    const options: FileBoxOptions = {
      buffer,
      md5,
      name: name || 'buffer.dat',
      type : FileBoxType.Buffer,
    }
    return new this(options)
  }

  /**
   * @param base64
   * @param name the file name of the base64 data
   */
  static fromBase64 (
    base64: string,
    name?:   string,
    md5?:    string,
  ): FileBox {
    const options: FileBoxOptions = {
      base64,
      md5,
      name: name || 'base64.dat',
      type : FileBoxType.Base64,
    }
    return new this(options)
  }

  /**
   * dataURL: `data:image/png;base64,${base64Text}`,
   */
  static fromDataURL (
    dataUrl : string,
    name?    : string,
    md5?     : string,
  ): FileBox {
    return this.fromBase64(
      dataUrlToBase64(dataUrl),
      name || 'data-url.dat',
      md5,
    )
  }

  /**
   *
   * @param qrCode the value of the QR Code. For example: `https://github.com`
   */
  static fromQRCode (
    qrCode: string,
    md5?:   string,
  ): FileBox {
    const options: FileBoxOptions = {
      md5,
      name: 'qrcode.png',
      qrCode,
      type: FileBoxType.QRCode,
    }
    return new this(options)
  }

  protected static uuidToStream?:    UuidLoader
  protected static uuidFromStream?:  UuidSaver

  static fromUuid (
    uuid: string,
    options?: {
      name?: string,
      size?: number,
      md5? : string,
    },
  ): FileBox

  /**
   * @deprecated use `fromUuid(name, options)` instead
   */
  static fromUuid (
    uuid: string,
    name?: string,
    md5?: string,
  ): FileBox

  /**
   * @param uuid the UUID of the file. For example: `6f88b03c-1237-4f46-8db2-98ef23200551`
   * @param name the name of the file. For example: `video.mp4`
   */
  static fromUuid (
    uuid: string,
    nameOrOptions?: string | {
      name?: string,
      size?: number,
      md5? : string
    },
  ): FileBox {
    let name: undefined | string
    let size: undefined | number
    let md5 : undefined | string

    if (typeof nameOrOptions === 'object') {
      name = nameOrOptions.name
      size = nameOrOptions.size
      md5  = nameOrOptions.md5
    } else {
      name = nameOrOptions
    }

    const options: FileBoxOptions = {
      md5,
      name: name || `${uuid}.dat`,
      size,
      type: FileBoxType.Uuid,
      uuid,
    }
    return new this(options)
  }

  /**
   * UUID Type FielBox Loader
   */
  static setUuidLoader (
    loader: UuidLoader,
  ): void {
    if (Object.prototype.hasOwnProperty.call(this, 'uuidToStream')) {
      throw new Error('this FileBox has been set resolver before, can not set twice')
    }
    this.uuidToStream = loader
  }

  /**
   * UUID Type FielBox Saver
   */
  static setUuidSaver (
    saver: UuidSaver,
  ): void {
    if (Object.prototype.hasOwnProperty.call(this, 'uuidFromStream')) {
      throw new Error('this FileBox has been set register before, can not set twice')
    }
    this.uuidFromStream = saver
  }

  /**
   *
   * @static
   * @param {(FileBoxJsonObject | string)} obj
   * @returns {FileBox}
   */
  static fromJSON (obj: FileBoxJsonObject | string): FileBox {
    if (typeof obj === 'string') {
      obj = JSON.parse(obj) as FileBoxJsonObject
    }

    /**
     * Huan(202111): compatible with old FileBox.toJSON() key: `boxType`
     *  this is a breaking change made by v1.0
     *
     *  convert `obj.boxType` to `obj.type`
     *  (will be removed after Dec 31, 2022)
     */
    if (!(obj as any).type && 'boxType' in (obj as any)) {
      obj.type = (obj as any)['boxType']
    }

    let fileBox: FileBox

    switch (obj.type) {
      case FileBoxType.Base64:
        fileBox = this.fromBase64(
          obj.base64,
          obj.name,
          obj.md5,
        )
        break

      case FileBoxType.Url:
        fileBox = this.fromUrl(obj.url, {
          md5: obj.md5,
          name: obj.name,
          size: obj.size,
        })
        break

      case FileBoxType.QRCode:
        fileBox = this.fromQRCode(
          obj.qrCode,
          obj.md5,
        )
        break

      case FileBoxType.Uuid:
        fileBox = this.fromUuid(obj.uuid, {
          md5: obj.md5,
          name: obj.name,
          size: obj.size,
        })
        break

      default:
        throw new Error(`unknown filebox json object{type}: ${JSON.stringify(obj)}`)
    }

    if (obj.metadata) {
      (fileBox as FileBox).metadata = obj.metadata
    }

    return fileBox
  }

  /**
   *
   * Instance Properties
   *
   */
  readonly version = VERSION

  /**
   * We are using a getter for `type` is because
   *  getter name can be enumurated by the `Object.hasOwnProperties()`*
   *    but property name can not.
   *
   *  * required by `validInterface()`
   */
  readonly _type: FileBoxType
  get type () { return this._type }

  /**
   * the Content-Length of the file
   *  `SIZE_UNKNOWN(-1)` means unknown
   *
   * @example
   * ```ts
   * const fileBox = FileBox.fromUrl('http://example.com/image.png')
   * await fileBox.ready()
   * console.log(fileBox.size)
   * // > 102400 <- this is the size of the remote image.png
   * ```
   */
  _size?: number
  get size (): number {
    if (this._size) {
      return this._size
    }
    return UNKNOWN_SIZE
  }

  /**
   * File MD5 Sum
   */
  readonly md5: undefined | string

  /**
   * @deprecated: use `mediaType` instead. will be removed after Dec 31, 2022
   */
  mimeType = 'application/unknown'

  /**
   * (Internet) Media Type is the proper technical term of `MIME Type`
   *  @see https://stackoverflow.com/a/9277778/1123955
   *
   * @example 'text/plain'
   */
  protected _mediaType?: string
  get mediaType (): string {
    if (this._mediaType) {
      return this._mediaType
    }
    return 'application/unknown'
  }

  protected _name: string
  get name (): string {
    return this._name
  }

  protected _metadata?: Metadata
  get metadata (): Metadata {
    if (this._metadata) {
      return this._metadata
    }
    return EMPTY_META_DATA
  }

  set metadata (data: Metadata) {
    if (this._metadata) {
      throw new Error('metadata can not be modified after set')
    }
    this._metadata = { ...data }
    Object.freeze(this._metadata)
  }

  /**
   * Lazy load data: (can be serialized to JSON)
   *  Do not read file to Buffer until there's a consumer.
   */
  private readonly base64?    : string
  private readonly remoteUrl? : string
  private readonly qrCode?    : string
  private readonly uuid?      : string

  /**
   * Can not be serialized to JSON
   */
  private readonly buffer?    : Buffer
  private readonly localPath? : string
  private readonly stream?    : Readable

  private readonly headers?: HTTP.OutgoingHttpHeaders

  constructor (
    options: FileBoxOptions,
  ) {
    // Only keep `basename` in this.name
    this._name = PATH.basename(options.name)
    this._type = options.type

    /**
     * Unknown file type MIME: `'application/unknown'`
     *  @see https://stackoverflow.com/a/6080707/1123955
     */
    this._mediaType = mime.getType(this.name) ?? undefined
    this.md5 = options.md5

    switch (options.type) {
      case FileBoxType.Buffer:
        this.buffer = options.buffer
        this._size   = options.buffer.length
        break

      case FileBoxType.File:
        if (!options.path) {
          throw new Error('no path')
        }
        this.localPath  = options.path
        this._size       = FS.statSync(this.localPath).size
        break

      case FileBoxType.Url:
        if (!options.url) {
          throw new Error('no url')
        }
        this.remoteUrl = options.url

        if (options.headers) {
          this.headers = options.headers
        }
        if (options.size) {
          this._size = options.size
        } else {
          /**
           * Add a background task to fetch remote file name & size
           *
           * TODO: how to improve it?
           */
          // this.syncUrlMetadata().catch(console.error)
        }

        break

      case FileBoxType.Stream:
        this.stream = options.stream
        if (options.size) {
          this._size = options.size
        }
        break

      case FileBoxType.QRCode:
        if (!options.qrCode) {
          throw new Error('no QR Code')
        }
        this.qrCode = options.qrCode
        break

      case FileBoxType.Base64:
        if (!options.base64) {
          throw new Error('no Base64 data')
        }
        this.base64 = options.base64
        this._size  = Buffer.byteLength(options.base64, 'base64')
        break

      case FileBoxType.Uuid:
        if (!options.uuid) {
          throw new Error('no UUID data')
        }
        this.uuid = options.uuid
        if (options.size) {
          this._size = options.size
        }
        break

      default:
        throw new Error(`unknown options(type): ${JSON.stringify(options)}`)
    }

  }

  async ready (): Promise<void> {
    switch (this.type) {
      case FileBoxType.Url:
        await this._syncUrlMetadata()
        break

      case FileBoxType.QRCode:
        if (this.size === UNKNOWN_SIZE) {
          this._size = (await this.toBuffer()).length
        }
        break

      default:
        break
    }
  }

  /**
   * @todo use http.get/gets instead of Request
   */
  protected async _syncUrlMetadata (): Promise<void> {
    /**
     * https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Disposition
     *  > Content-Disposition: attachment; filename="cool.html"
     */

    if (this.type !== FileBoxType.Url) {
      throw new Error('type is not Url')
    }
    if (!this.remoteUrl) {
      throw new Error('no url')
    }

    const headers = await httpHeadHeader(this.remoteUrl)

    const httpFilename = httpHeaderToFileName(headers)
    if (httpFilename) {
      this._name = httpFilename
    }

    if (!this.name) {
      throw new Error('NONAME')
    }

    const httpMediaType = headers['content-type'] || (httpFilename && mime.getType(httpFilename))
    if (httpMediaType) {
      this._mediaType = httpMediaType
    }

    if (headers['content-length']) {
      this._size = Number(headers['content-length'])
    }
  }

  /**
   *
   * toXXX methods
   *
   */
  toString () {
    return [
      'FileBox#',
      FileBoxType[this.type],
      '<',
      this.name,
      '>',
    ].join('')
  }

  toJSON (): FileBoxJsonObject {
    const objCommon: FileBoxOptionsCommon = {
      md5      : this.md5,
      metadata : this.metadata,
      name     : this.name,
    }

    if (typeof this.size !== 'undefined') {
      objCommon.size = this.size
    }

    let obj: FileBoxJsonObject

    switch (this.type) {
      case FileBoxType.Url: {
        if (!this.remoteUrl) {
          throw new Error('no url')
        }
        const objUrl: FileBoxOptionsUrl = {
          headers : this.headers,
          type    : FileBoxType.Url,
          url     : this.remoteUrl,
        }
        obj = {
          ...objCommon,
          ...objUrl,
        }
        break
      }

      case FileBoxType.QRCode: {
        if (!this.qrCode) {
          throw new Error('no qr code')
        }
        const objQRCode: FileBoxOptionsQRCode = {
          qrCode : this.qrCode,
          type   : FileBoxType.QRCode,
        }
        obj = {
          ...objCommon,
          ...objQRCode,
        }
        break
      }

      case FileBoxType.Base64: {
        if (!this.base64) {
          throw new Error('no base64 data')
        }
        const objBase64: FileBoxOptionsBase64 = {
          base64 : this.base64,
          type   : FileBoxType.Base64,
        }
        obj = {
          ...objCommon,
          ...objBase64,
        }
        break
      }

      case FileBoxType.Uuid: {
        if (!this.uuid) {
          throw new Error('no uuid data')
        }
        const objUuid: FileBoxOptionsUuid = {
          type : FileBoxType.Uuid,
          uuid : this.uuid,
        }
        obj = {
          ...objCommon,
          ...objUuid,
        }
        break
      }

      default:
        void this.type
        throw new Error('FileBox.toJSON() can only work on limited FileBoxType(s). See: <https://github.com/huan/file-box/issues/25>')
    }

    /**
     * Huan(202111): compatible with old FileBox.toJSON() key: `boxType`
     *  this is a breaking change made by v1.0
     *
     *  save `obj.type` a copy to `obj.boxType`
     *  (will be removed after Dec 31, 2022)
     */
    (obj as any)['boxType'] = obj.type

    return obj
  }

  async toStream (): Promise<Readable> {
    let stream: Readable

    switch (this.type) {
      case FileBoxType.Buffer:
        stream = this._transformBufferToStream()
        break

      case FileBoxType.File:
        stream = this._transformFileToStream()
        break

      case FileBoxType.Url:
        stream = await this._transformUrlToStream()
        break

      case FileBoxType.Stream:
        if (!this.stream) {
          throw new Error('no stream')
        }

        /**
          * Huan(202109): the stream.destroyed will not be `true`
          *   when we have read all the data
          *   after we change some code.
          * The reason is unbase64 : this.base64,
          type   : FileBoxType.Base64,known... so we change to check `readable`
          */
        if (!this.stream.readable) {
          throw new Error('The stream is not readable. Maybe has already been consumed, and now it was drained. See: https://github.com/huan/file-box/issues/50')
        }

        stream = this.stream
        break

      case FileBoxType.QRCode:
        if (!this.qrCode) {
          throw new Error('no QR Code')
        }
        stream = await this._transformQRCodeToStream()
        break

      case FileBoxType.Base64:
        if (!this.base64) {
          throw new Error('no base64 data')
        }
        stream = this._transformBase64ToStream()
        break

      case FileBoxType.Uuid: {
        if (!this.uuid) {
          throw new Error('no uuid data')
        }
        const FileBoxKlass = instanceToClass(this, FileBox)

        if (!FileBoxKlass.uuidToStream) {
          throw new Error('need to call FileBox.setUuidLoader() to set UUID loader first.')
        }

        stream = await FileBoxKlass.uuidToStream.call(this, this.uuid)
        break
      }

      default:
        throw new Error('not supported FileBoxType: ' + FileBoxType[this.type])
    }

    return stream
  }

  /**
   * https://stackoverflow.com/a/16044400/1123955
   */
  private _transformBufferToStream (buffer?: Buffer): Readable {
    const bufferStream = new PassThrough()
    bufferStream.end(buffer || this.buffer)

    /**
     * Use small `chunks` with `toStream()` #44
     * https://github.com/huan/file-box/issues/44
     */
    return bufferStream.pipe(sizedChunkTransformer())
  }

  private _transformBase64ToStream (): Readable {
    if (!this.base64) {
      throw new Error('no base64 data')
    }
    const buffer = Buffer.from(this.base64, 'base64')
    return this._transformBufferToStream(buffer)
  }

  private _transformFileToStream (): Readable {
    if (!this.localPath) {
      throw new Error('no url(path)')
    }
    return FS.createReadStream(this.localPath)
  }

  private async _transformUrlToStream (): Promise<Readable> {
    return new Promise<Readable>((resolve, reject) => {
      if (this.remoteUrl) {
        httpStream(this.remoteUrl, this.headers)
          .then(resolve)
          .catch(reject)
      } else {
        reject(new Error('no url'))
      }
    })
  }

  private async _transformQRCodeToStream (): Promise<Readable> {
    if (!this.qrCode) {
      throw new Error('no QR Code Value found')
    }
    const stream = qrValueToStream(this.qrCode)
    return stream
  }

  /**
   * save file
   *
   * @param filePath save file
   */
  async toFile (
    filePath?: string,
    overwrite = false,
  ): Promise<void> {
    if (this.type === FileBoxType.Url) {
      if (!this.mediaType || !this.name) {
        await this._syncUrlMetadata()
      }
    }
    const fullFilePath = PATH.resolve(filePath || this.name)

    const exist = FS.existsSync(fullFilePath)

    if (exist && !overwrite) {
      throw new Error(`FileBox.toFile(${fullFilePath}): file exist. use FileBox.toFile(${fullFilePath}, true) to force overwrite.`)
    }

    const writeStream = FS.createWriteStream(fullFilePath)

    /**
      * Huan(202109): make sure the file can be opened for writting
      *   before we pipe the stream to it
      */
    await new Promise((resolve, reject) => writeStream
      .once('open', resolve)
      .once('error', reject),
    )
    /**
      * Start pipe
      */
    await new Promise((resolve, reject) => {
      writeStream
        .once('close', resolve)
        .once('error', reject)

      this.pipe(writeStream)
    })
  }

  async toBase64 (): Promise<string> {
    if (this.type === FileBoxType.Base64) {
      if (!this.base64) {
        throw new Error('no base64 data')
      }
      return this.base64
    }

    const buffer = await this.toBuffer()
    return buffer.toString('base64')
  }

  /**
   * dataUrl: `data:image/png;base64,${base64Text}',
   */
  async toDataURL (): Promise<string> {
    const base64Text = await this.toBase64()

    if (!this.mediaType) {
      throw new Error('no mediaType found')
    }

    const dataUrl = [
      'data:',
      this.mediaType,
      ';base64,',
      base64Text,
    ].join('')

    return dataUrl
  }

  async toBuffer (): Promise<Buffer> {
    if (this.type === FileBoxType.Buffer) {
      if (!this.buffer) {
        throw new Error('no buffer!')
      }
      return this.buffer
    }

    const stream = new PassThrough()
    this.pipe(stream)

    const buffer: Buffer = await streamToBuffer(stream)
    return buffer
  }

  async toQRCode (): Promise<string> {
    if (this.type === FileBoxType.QRCode) {
      if (!this.qrCode) {
        throw new Error('no QR Code!')
      }
      return this.qrCode
    }

    const buf = await this.toBuffer()
    const qrValue = await bufferToQrValue(buf)

    return qrValue
  }

  async toUuid (): Promise<string> {
    if (this.type === FileBoxType.Uuid) {
      if (!this.uuid) {
        throw new Error('no uuid found for a UUID type file box!')
      }
      return this.uuid
    }

    const FileBoxKlass = instanceToClass(this, FileBox)

    if (!FileBoxKlass.uuidFromStream) {
      throw new Error('need to use FileBox.setUuidSaver() before dealing with UUID')
    }

    const stream = new PassThrough()
    this.pipe(stream)

    return FileBoxKlass.uuidFromStream.call(this, stream)
  }

  /**
   *
   * toXXX methods END
   *
   */

  pipe<T extends Writable> (
    destination: T,
  ): T {
    this.toStream().then(stream => {
      stream.on('error', e => {
        console.info('error:', e)

        destination.emit('error', e)
      })
      return stream.pipe(destination)
    }).catch(e => destination.emit('error', e))
    return destination
  }

}

/**
 * Huan(202110): lazy initialize `interfaceOfClass(FileBox)`
 *  because we only can reference a class after its declaration
 */
interfaceOfFileBox      = interfaceOfClass(FileBox)<FileBoxInterface>()
looseInstanceOfFileBox  = looseInstanceOfClass(FileBox)

export {
  FileBox,
}