standardnotes-app-web/app/assets/javascripts/Services/ArchiveManager.ts

import { WebApplication } from '@/UIModels/Application'
import { parseFileName } from '@standardnotes/filepicker'
import {
  ContentType,
  BackupFile,
  BackupFileDecryptedContextualPayload,
  NoteContent,
} from '@standardnotes/snjs'

function sanitizeFileName(name: string): string {
  return name.trim().replace(/[.\\/:"?*|<>]/g, '_')
}

function zippableFileName(name: string, suffix = '', format = 'txt'): string {
  const sanitizedName = sanitizeFileName(name)
  const nameEnd = suffix + '.' + format
  const maxFileNameLength = 100
  return sanitizedName.slice(0, maxFileNameLength - nameEnd.length) + nameEnd
}

type ZippableData = {
  filename: string
  content: Blob
}[]

type ObjectURL = string

export class ArchiveManager {
  private readonly application: WebApplication
  private textFile?: string

  constructor(application: WebApplication) {
    this.application = application
  }

  public async getMimeType(ext: string) {
    return (await import('@zip.js/zip.js')).getMimeType(ext)
  }

  public async downloadBackup(encrypted: boolean): Promise<void> {
    const data = encrypted
      ? await this.application.createEncryptedBackupFile(true)
      : await this.application.createDecryptedBackupFile()

    if (!data) {
      return
    }

    const blobData = new Blob([JSON.stringify(data, null, 2)], {
      type: 'text/json',
    })

    if (encrypted) {
      this.downloadData(
        blobData,
        `Standard Notes Encrypted Backup and Import File - ${this.formattedDate()}.txt`,
      )
    } else {
      this.downloadZippedDecryptedItems(data).catch(console.error)
    }
  }

  private formattedDate() {
    const string = `${new Date()}`
    // Match up to the first parenthesis, i.e do not include '(Central Standard Time)'
    const matches = string.match(/^(.*?) \(/)
    if (matches && matches.length >= 2) {
      return matches[1]
    }
    return string
  }

  private async downloadZippedDecryptedItems(data: BackupFile) {
    const zip = await import('@zip.js/zip.js')
    const zipWriter = new zip.ZipWriter(new zip.BlobWriter('application/zip'))
    const items = data.items

    const blob = new Blob([JSON.stringify(data, null, 2)], {
      type: 'text/plain',
    })

    const fileName = zippableFileName('Standard Notes Backup and Import File')
    await zipWriter.add(fileName, new zip.BlobReader(blob))

    let index = 0
    const nextFile = async () => {
      const item = items[index]
      let name, contents

      if (item.content_type === ContentType.Note) {
        const note = item as BackupFileDecryptedContextualPayload<NoteContent>
        name = note.content.title
        contents = note.content.text
      } else {
        name = item.content_type
        contents = JSON.stringify(item.content, null, 2)
      }

      if (!name) {
        name = ''
      }

      const blob = new Blob([contents], { type: 'text/plain' })
      const fileName =
        `Items/${sanitizeFileName(item.content_type)}/` +
        zippableFileName(name, `-${item.uuid.split('-')[0]}`)
      await zipWriter.add(fileName, new zip.BlobReader(blob))

      index++
      if (index < items.length) {
        await nextFile()
      } else {
        const finalBlob = await zipWriter.close()
        this.downloadData(finalBlob, `Standard Notes Backup - ${this.formattedDate()}.zip`)
      }
    }

    await nextFile()
  }

  async zipData(data: ZippableData): Promise<Blob> {
    const zip = await import('@zip.js/zip.js')
    const writer = new zip.ZipWriter(new zip.BlobWriter('application/zip'))

    for (let i = 0; i < data.length; i++) {
      const { name, ext } = parseFileName(data[i].filename)
      await writer.add(zippableFileName(name, '', ext), new zip.BlobReader(data[i].content))
    }

    const zipFileAsBlob = await writer.close()

    return zipFileAsBlob
  }

  async downloadDataAsZip(data: ZippableData) {
    const zipFileAsBlob = await this.zipData(data)
    this.downloadData(zipFileAsBlob, `Standard Notes Export - ${this.formattedDate()}.zip`)
  }

  private hrefForData(data: Blob) {
    // If we are replacing a previously generated file we need to
    // manually revoke the object URL to avoid memory leaks.
    if (this.textFile) {
      window.URL.revokeObjectURL(this.textFile)
    }
    this.textFile = window.URL.createObjectURL(data)
    // returns a URL you can use as a href
    return this.textFile
  }

  downloadData(data: Blob | ObjectURL, fileName: string) {
    const link = document.createElement('a')
    link.setAttribute('download', fileName)
    link.href = typeof data === 'string' ? data : this.hrefForData(data)
    document.body.appendChild(link)
    link.click()
    link.remove()
  }
}