const Path = require('path')

const AudioFile = require('../objects/files/AudioFile')

const prober = require('../utils/prober')
const Logger = require('../Logger')
const { LogLevel } = require('../utils/constants')

class AudioFileScanner {
  constructor() { }

  getTrackAndDiscNumberFromFilename(mediaMetadataFromScan, audioLibraryFile) {
    const { title, author, series, publishYear } = mediaMetadataFromScan
    const { filename, path } = audioLibraryFile.metadata
    var partbasename = Path.basename(filename, Path.extname(filename))

    // Remove title, author, series, and publishYear from filename if there
    if (title) partbasename = partbasename.replace(title, '')
    if (author) partbasename = partbasename.replace(author, '')
    if (series) partbasename = partbasename.replace(series, '')
    if (publishYear) partbasename = partbasename.replace(publishYear)

    // Look for disc number
    var discNumber = null
    var discMatch = partbasename.match(/\b(disc|cd) ?(\d\d?)\b/i)
    if (discMatch && discMatch.length > 2 && discMatch[2]) {
      if (!isNaN(discMatch[2])) {
        discNumber = Number(discMatch[2])
      }

      // Remove disc number from filename
      partbasename = partbasename.replace(/\b(disc|cd) ?(\d\d?)\b/i, '')
    }

    // Look for disc number in folder path e.g. /Book Title/CD01/audiofile.mp3
    var pathdir = Path.dirname(path).split('/').pop()
    if (pathdir && /^cd\d{1,3}$/i.test(pathdir)) {
      var discFromFolder = Number(pathdir.replace(/cd/i, ''))
      if (!isNaN(discFromFolder) && discFromFolder !== null) discNumber = discFromFolder
    }

    var numbersinpath = partbasename.match(/\d{1,4}/g)
    var trackNumber = numbersinpath && numbersinpath.length ? parseInt(numbersinpath[0]) : null
    return {
      trackNumber,
      discNumber
    }
  }

  getAverageScanDurationMs(results) {
    if (!results.length) return 0
    var total = 0
    for (let i = 0; i < results.length; i++) total += results[i].elapsed
    return Math.floor(total / results.length)
  }

  async scan(audioLibraryFile, mediaMetadataFromScan, verbose = false) {
    var probeStart = Date.now()
    var probeData = await prober.probe(audioLibraryFile.metadata.path, verbose)
    if (probeData.error) {
      Logger.error(`[AudioFileScanner] ${probeData.error} : "${audioLibraryFile.metadata.path}"`)
      return null
    }

    var audioFile = new AudioFile()
    audioFile.trackNumFromMeta = probeData.trackNumber
    audioFile.discNumFromMeta = probeData.discNumber

    const { trackNumber, discNumber } = this.getTrackAndDiscNumberFromFilename(mediaMetadataFromScan, audioLibraryFile)
    audioFile.trackNumFromFilename = trackNumber
    audioFile.discNumFromFilename = discNumber

    audioFile.setDataFromProbe(audioLibraryFile, probeData)

    return {
      audioFile,
      elapsed: Date.now() - probeStart
    }
  }

  // Returns array of { AudioFile, elapsed, averageScanDuration } from audio file scan objects
  async executeAudioFileScans(audioLibraryFiles, scanData) {
    var mediaMetadataFromScan = scanData.mediaMetadata || null
    var proms = []
    for (let i = 0; i < audioLibraryFiles.length; i++) {
      proms.push(this.scan(audioLibraryFiles[i], mediaMetadataFromScan))
    }
    var scanStart = Date.now()
    var results = await Promise.all(proms).then((scanResults) => scanResults.filter(sr => sr))
    return {
      audioFiles: results.map(r => r.audioFile),
      elapsed: Date.now() - scanStart,
      averageScanDuration: this.getAverageScanDurationMs(results)
    }
  }

  isSequential(nums) {
    if (!nums || !nums.length) return false
    if (nums.length === 1) return true
    var prev = nums[0]
    for (let i = 1; i < nums.length; i++) {
      if (nums[i] - prev > 1) return false
      prev = nums[i]
    }
    return true
  }

  removeDupes(nums) {
    if (!nums || !nums.length) return []
    if (nums.length === 1) return nums

    var nodupes = [nums[0]]
    nums.forEach((num) => {
      if (num > nodupes[nodupes.length - 1]) nodupes.push(num)
    })
    return nodupes
  }

  runSmartTrackOrder(libraryItem, audioFiles) {
    var discsFromFilename = []
    var tracksFromFilename = []
    var discsFromMeta = []
    var tracksFromMeta = []

    audioFiles.forEach((af) => {
      if (af.discNumFromFilename !== null) discsFromFilename.push(af.discNumFromFilename)
      if (af.discNumFromMeta !== null) discsFromMeta.push(af.discNumFromMeta)
      if (af.trackNumFromFilename !== null) tracksFromFilename.push(af.trackNumFromFilename)
      if (af.trackNumFromMeta !== null) tracksFromMeta.push(af.trackNumFromMeta)
      af.validateTrackIndex() // Sets error if no valid track number
    })
    discsFromFilename.sort((a, b) => a - b)
    discsFromMeta.sort((a, b) => a - b)
    tracksFromFilename.sort((a, b) => a - b)
    tracksFromMeta.sort((a, b) => a - b)

    var discKey = null
    if (discsFromMeta.length === audioFiles.length && this.isSequential(discsFromMeta)) {
      discKey = 'discNumFromMeta'
    } else if (discsFromFilename.length === audioFiles.length && this.isSequential(discsFromFilename)) {
      discKey = 'discNumFromFilename'
    }

    var trackKey = null
    tracksFromFilename = this.removeDupes(tracksFromFilename)
    tracksFromMeta = this.removeDupes(tracksFromMeta)
    if (tracksFromFilename.length > tracksFromMeta.length) {
      trackKey = 'trackNumFromFilename'
    } else {
      trackKey = 'trackNumFromMeta'
    }


    if (discKey !== null) {
      Logger.debug(`[AudioFileScanner] Smart track order for "${libraryItem.media.metadata.title}" using disc key ${discKey} and track key ${trackKey}`)
      audioFiles.sort((a, b) => {
        let Dx = a[discKey] - b[discKey]
        if (Dx === 0) Dx = a[trackKey] - b[trackKey]
        return Dx
      })
    } else {
      Logger.debug(`[AudioFileScanner] Smart track order for "${libraryItem.media.metadata.title}" using track key ${trackKey}`)
      audioFiles.sort((a, b) => a[trackKey] - b[trackKey])
    }

    for (let i = 0; i < audioFiles.length; i++) {
      audioFiles[i].index = i + 1
      var existingAF = libraryItem.media.findFileWithInode(audioFiles[i].ino)
      if (existingAF) {
        if (existingAF.updateFromScan) existingAF.updateFromScan(audioFiles[i])
      } else {
        libraryItem.media.audioFiles.push(audioFiles[i])
      }
    }
  }

  async scanAudioFiles(audioLibraryFiles, scanData, libraryItem, preferAudioMetadata, libraryScan = null) {
    var hasUpdated = false

    var audioScanResult = await this.executeAudioFileScans(audioLibraryFiles, scanData)
    if (audioScanResult.audioFiles.length) {
      if (libraryScan) {
        libraryScan.addLog(LogLevel.DEBUG, `Library Item "${scanData.path}" Audio file scan took ${audioScanResult.elapsed}ms for ${audioScanResult.audioFiles.length} with average time of ${audioScanResult.averageScanDuration}ms`)
      }

      var totalAudioFilesToInclude = audioScanResult.audioFiles.length
      var newAudioFiles = audioScanResult.audioFiles.filter(af => {
        return !libraryItem.libraryFiles.find(lf => lf.ino === af.ino)
      })

      // Adding audio files to book media
      if (libraryItem.mediaType === 'book') {
        if (newAudioFiles.length) {
          // Single Track Audiobooks
          if (totalAudioFilesToInclude === 1) {
            var af = audioScanResult.audioFiles[0]
            af.index = 1
            libraryItem.media.audioFiles.push(af)
            hasUpdated = true
          } else {
            this.runSmartTrackOrder(libraryItem, audioScanResult.audioFiles)
            hasUpdated = true
          }
        } else {
          Logger.debug(`[AudioFileScanner] No audio track re-order required`)
          // Only update metadata not index
          audioScanResult.audioFiles.forEach((af) => {
            var existingAF = libraryItem.media.findFileWithInode(af.ino)
            if (existingAF) {
              af.index = existingAF.index
              if (existingAF.updateFromScan && existingAF.updateFromScan(af)) {
                hasUpdated = true
              }
            }
          })
        }

        // Set book details from audio file ID3 tags, optional prefer
        if (libraryItem.media.setMetadataFromAudioFile(preferAudioMetadata)) {
          hasUpdated = true
        }

        if (hasUpdated) {
          libraryItem.media.rebuildTracks()
        }
      } // End Book media type
    }
    return hasUpdated
  }
}
module.exports = new AudioFileScanner()