audiobookshelf/server/utils/parsers/parseComicMetadata.js

const Path = require('path')
const globals = require('../globals')
const fs = require('../../libs/fsExtra')
const Logger = require('../../Logger')
const Archive = require('../../libs/libarchive/archive')
const { xmlToJSON } = require('../index')
const parseComicInfoMetadata = require('./parseComicInfoMetadata')

/**
 * 
 * @param {string} filepath 
 * @returns {Promise<Buffer>}
 */
async function getComicFileBuffer(filepath) {
  if (!await fs.pathExists(filepath)) {
    Logger.error(`Comic path does not exist "${filepath}"`)
    return null
  }
  try {
    return fs.readFile(filepath)
  } catch (error) {
    Logger.error(`Failed to read comic at "${filepath}"`, error)
    return null
  }
}

/**
 * Extract cover image from comic return true if success
 * 
 * @param {string} comicPath 
 * @param {string} comicImageFilepath 
 * @param {string} outputCoverPath 
 * @returns {Promise<boolean>}
 */
async function extractCoverImage(comicPath, comicImageFilepath, outputCoverPath) {
  const comicFileBuffer = await getComicFileBuffer(comicPath)
  if (!comicFileBuffer) return null

  const archive = await Archive.open(comicFileBuffer)
  const fileEntry = await archive.extractSingleFile(comicImageFilepath)

  if (!fileEntry?.fileData) {
    Logger.error(`[parseComicMetadata] Invalid file entry data for comicPath "${comicPath}"/${comicImageFilepath}`)
    return false
  }

  try {
    await fs.writeFile(outputCoverPath, fileEntry.fileData)
    return true
  } catch (error) {
    Logger.error(`[parseComicMetadata] Failed to extract image from comicPath "${comicPath}"`, error)
    return false
  }
}
module.exports.extractCoverImage = extractCoverImage

/**
 * Parse metadata from comic
 * 
 * @param {import('../../models/Book').EBookFileObject} ebookFile 
 * @returns {Promise<import('./parseEbookMetadata').EBookFileScanData>}
 */
async function parse(ebookFile) {
  const comicPath = ebookFile.metadata.path
  Logger.debug(`Parsing metadata from comic at "${comicPath}"`)

  const comicFileBuffer = await getComicFileBuffer(comicPath)
  if (!comicFileBuffer) return null

  const archive = await Archive.open(comicFileBuffer)

  const fileObjects = await archive.getFilesArray()

  fileObjects.sort((a, b) => {
    return a.file.name.localeCompare(b.file.name, undefined, {
      numeric: true,
      sensitivity: 'base'
    })
  })

  let metadata = null
  const comicInfo = fileObjects.find(fo => fo.file.name === 'ComicInfo.xml')
  if (comicInfo) {
    const comicInfoEntry = await comicInfo.file.extract()
    if (comicInfoEntry?.fileData) {
      const comicInfoStr = new TextDecoder().decode(comicInfoEntry.fileData)
      const comicInfoJson = await xmlToJSON(comicInfoStr)
      if (comicInfoJson) {
        metadata = parseComicInfoMetadata.parse(comicInfoJson)
      }
    }
  }

  const payload = {
    path: comicPath,
    ebookFormat: ebookFile.ebookFormat,
    metadata
  }

  const firstImage = fileObjects.find(fo => globals.SupportedImageTypes.includes(Path.extname(fo.file.name).toLowerCase().slice(1)))
  if (firstImage?.file?._path) {
    payload.ebookCoverPath = firstImage.file._path
  } else {
    Logger.warn(`Cover image not found in comic at "${comicPath}"`)
  }

  return payload
}
module.exports.parse = parse