import { createWriteStream } from 'fs'
import { ensureDir, move, pathExists, remove, writeFile } from 'fs-extra'
import { join } from 'path'
import { CONFIG } from '@server/initializers/config'
import { HttpStatusCode } from '../../shared/models/http/http-error-codes'
import { VideoResolution } from '../../shared/models/videos'
import { CONSTRAINTS_FIELDS, VIDEO_CATEGORIES, VIDEO_LANGUAGES, VIDEO_LICENCES } from '../initializers/constants'
import { peertubeTruncate, pipelinePromise, root } from './core-utils'
import { isVideoFileExtnameValid } from './custom-validators/videos'
import { logger } from './logger'
import { peertubeGot } from './requests'
import { generateVideoImportTmpPath } from './utils'

export type YoutubeDLInfo = {
  name?: string
  description?: string
  category?: number
  language?: string
  licence?: number
  nsfw?: boolean
  tags?: string[]
  thumbnailUrl?: string
  ext?: string
  originallyPublishedAt?: Date
}

export type YoutubeDLSubs = {
  language: string
  filename: string
  path: string
}[]

const processOptions = {
  maxBuffer: 1024 * 1024 * 10 // 10MB
}

class YoutubeDL {

  constructor (private readonly url: string = '', private readonly enabledResolutions: number[] = []) {

  }

  getYoutubeDLInfo (opts?: string[]): Promise<YoutubeDLInfo> {
    return new Promise<YoutubeDLInfo>((res, rej) => {
      let args = opts || []

      if (CONFIG.IMPORT.VIDEOS.HTTP.FORCE_IPV4) {
        args.push('--force-ipv4')
      }

      args = this.wrapWithProxyOptions(args)
      args = [ '-f', this.getYoutubeDLVideoFormat() ].concat(args)

      YoutubeDL.safeGetYoutubeDL()
        .then(youtubeDL => {
          youtubeDL.getInfo(this.url, args, processOptions, (err, info) => {
            if (err) return rej(err)
            if (info.is_live === true) return rej(new Error('Cannot download a live streaming.'))

            const obj = this.buildVideoInfo(this.normalizeObject(info))
            if (obj.name && obj.name.length < CONSTRAINTS_FIELDS.VIDEOS.NAME.min) obj.name += ' video'

            return res(obj)
          })
        })
        .catch(err => rej(err))
    })
  }

  getYoutubeDLSubs (opts?: object): Promise<YoutubeDLSubs> {
    return new Promise<YoutubeDLSubs>((res, rej) => {
      const cwd = CONFIG.STORAGE.TMP_DIR
      const options = opts || { all: true, format: 'vtt', cwd }

      YoutubeDL.safeGetYoutubeDL()
        .then(youtubeDL => {
          youtubeDL.getSubs(this.url, options, (err, files) => {
            if (err) return rej(err)
            if (!files) return []

            logger.debug('Get subtitles from youtube dl.', { url: this.url, files })

            const subtitles = files.reduce((acc, filename) => {
              const matched = filename.match(/\.([a-z]{2})(-[a-z]+)?\.(vtt|ttml)/i)
              if (!matched || !matched[1]) return acc

              return [
                ...acc,
                {
                  language: matched[1],
                  path: join(cwd, filename),
                  filename
                }
              ]
            }, [])

            return res(subtitles)
          })
        })
        .catch(err => rej(err))
    })
  }

  getYoutubeDLVideoFormat () {
    /**
     * list of format selectors in order or preference
     * see https://github.com/ytdl-org/youtube-dl#format-selection
     *
     * case #1 asks for a mp4 using h264 (avc1) and the exact resolution in the hope
     * of being able to do a "quick-transcode"
     * case #2 is the first fallback. No "quick-transcode" means we can get anything else (like vp9)
     * case #3 is the resolution-degraded equivalent of #1, and already a pretty safe fallback
     *
     * in any case we avoid AV1, see https://github.com/Chocobozzz/PeerTube/issues/3499
     **/
    const resolution = this.enabledResolutions.length === 0
      ? VideoResolution.H_720P
      : Math.max(...this.enabledResolutions)

    return [
      `bestvideo[vcodec^=avc1][height=${resolution}]+bestaudio[ext=m4a]`, // case #1
      `bestvideo[vcodec!*=av01][vcodec!*=vp9.2][height=${resolution}]+bestaudio`, // case #2
      `bestvideo[vcodec^=avc1][height<=${resolution}]+bestaudio[ext=m4a]`, // case #3
      `bestvideo[vcodec!*=av01][vcodec!*=vp9.2]+bestaudio`,
      'best[vcodec!*=av01][vcodec!*=vp9.2]', // case fallback for known formats
      'best' // Ultimate fallback
    ].join('/')
  }

  downloadYoutubeDLVideo (fileExt: string, timeout: number) {
    // Leave empty the extension, youtube-dl will add it
    const pathWithoutExtension = generateVideoImportTmpPath(this.url, '')

    let timer

    logger.info('Importing youtubeDL video %s to %s', this.url, pathWithoutExtension)

    let options = [ '-f', this.getYoutubeDLVideoFormat(), '-o', pathWithoutExtension ]
    options = this.wrapWithProxyOptions(options)

    if (process.env.FFMPEG_PATH) {
      options = options.concat([ '--ffmpeg-location', process.env.FFMPEG_PATH ])
    }

    logger.debug('YoutubeDL options for %s.', this.url, { options })

    return new Promise<string>((res, rej) => {
      YoutubeDL.safeGetYoutubeDL()
        .then(youtubeDL => {
          youtubeDL.exec(this.url, options, processOptions, async err => {
            clearTimeout(timer)

            try {
              // If youtube-dl did not guess an extension for our file, just use .mp4 as default
              if (await pathExists(pathWithoutExtension)) {
                await move(pathWithoutExtension, pathWithoutExtension + '.mp4')
              }

              const path = await this.guessVideoPathWithExtension(pathWithoutExtension, fileExt)

              if (err) {
                remove(path)
                  .catch(err => logger.error('Cannot delete path on YoutubeDL error.', { err }))

                return rej(err)
              }

              return res(path)
            } catch (err) {
              return rej(err)
            }
          })

          timer = setTimeout(() => {
            const err = new Error('YoutubeDL download timeout.')

            this.guessVideoPathWithExtension(pathWithoutExtension, fileExt)
              .then(path => remove(path))
              .finally(() => rej(err))
              .catch(err => {
                logger.error('Cannot remove file in youtubeDL timeout.', { err })
                return rej(err)
              })
          }, timeout)
        })
        .catch(err => rej(err))
    })
  }

  buildOriginallyPublishedAt (obj: any) {
    let originallyPublishedAt: Date = null

    const uploadDateMatcher = /^(\d{4})(\d{2})(\d{2})$/.exec(obj.upload_date)
    if (uploadDateMatcher) {
      originallyPublishedAt = new Date()
      originallyPublishedAt.setHours(0, 0, 0, 0)

      const year = parseInt(uploadDateMatcher[1], 10)
      // Month starts from 0
      const month = parseInt(uploadDateMatcher[2], 10) - 1
      const day = parseInt(uploadDateMatcher[3], 10)

      originallyPublishedAt.setFullYear(year, month, day)
    }

    return originallyPublishedAt
  }

  private async guessVideoPathWithExtension (tmpPath: string, sourceExt: string) {
    if (!isVideoFileExtnameValid(sourceExt)) {
      throw new Error('Invalid video extension ' + sourceExt)
    }

    const extensions = [ sourceExt, '.mp4', '.mkv', '.webm' ]

    for (const extension of extensions) {
      const path = tmpPath + extension

      if (await pathExists(path)) return path
    }

    throw new Error('Cannot guess path of ' + tmpPath)
  }

  private normalizeObject (obj: any) {
    const newObj: any = {}

    for (const key of Object.keys(obj)) {
      // Deprecated key
      if (key === 'resolution') continue

      const value = obj[key]

      if (typeof value === 'string') {
        newObj[key] = value.normalize()
      } else {
        newObj[key] = value
      }
    }

    return newObj
  }

  private buildVideoInfo (obj: any): YoutubeDLInfo {
    return {
      name: this.titleTruncation(obj.title),
      description: this.descriptionTruncation(obj.description),
      category: this.getCategory(obj.categories),
      licence: this.getLicence(obj.license),
      language: this.getLanguage(obj.language),
      nsfw: this.isNSFW(obj),
      tags: this.getTags(obj.tags),
      thumbnailUrl: obj.thumbnail || undefined,
      originallyPublishedAt: this.buildOriginallyPublishedAt(obj),
      ext: obj.ext
    }
  }

  private titleTruncation (title: string) {
    return peertubeTruncate(title, {
      length: CONSTRAINTS_FIELDS.VIDEOS.NAME.max,
      separator: /,? +/,
      omission: ' […]'
    })
  }

  private descriptionTruncation (description: string) {
    if (!description || description.length < CONSTRAINTS_FIELDS.VIDEOS.DESCRIPTION.min) return undefined

    return peertubeTruncate(description, {
      length: CONSTRAINTS_FIELDS.VIDEOS.DESCRIPTION.max,
      separator: /,? +/,
      omission: ' […]'
    })
  }

  private isNSFW (info: any) {
    return info.age_limit && info.age_limit >= 16
  }

  private getTags (tags: any) {
    if (Array.isArray(tags) === false) return []

    return tags
      .filter(t => t.length < CONSTRAINTS_FIELDS.VIDEOS.TAG.max && t.length > CONSTRAINTS_FIELDS.VIDEOS.TAG.min)
      .map(t => t.normalize())
      .slice(0, 5)
  }

  private getLicence (licence: string) {
    if (!licence) return undefined

    if (licence.includes('Creative Commons Attribution')) return 1

    for (const key of Object.keys(VIDEO_LICENCES)) {
      const peertubeLicence = VIDEO_LICENCES[key]
      if (peertubeLicence.toLowerCase() === licence.toLowerCase()) return parseInt(key, 10)
    }

    return undefined
  }

  private getCategory (categories: string[]) {
    if (!categories) return undefined

    const categoryString = categories[0]
    if (!categoryString || typeof categoryString !== 'string') return undefined

    if (categoryString === 'News & Politics') return 11

    for (const key of Object.keys(VIDEO_CATEGORIES)) {
      const category = VIDEO_CATEGORIES[key]
      if (categoryString.toLowerCase() === category.toLowerCase()) return parseInt(key, 10)
    }

    return undefined
  }

  private getLanguage (language: string) {
    return VIDEO_LANGUAGES[language] ? language : undefined
  }

  private wrapWithProxyOptions (options: string[]) {
    if (CONFIG.IMPORT.VIDEOS.HTTP.PROXY.ENABLED) {
      logger.debug('Using proxy for YoutubeDL')

      return [ '--proxy', CONFIG.IMPORT.VIDEOS.HTTP.PROXY.URL ].concat(options)
    }

    return options
  }

  // Thanks: https://github.com/przemyslawpluta/node-youtube-dl/blob/master/lib/downloader.js
  // We rewrote it to avoid sync calls
  static async updateYoutubeDLBinary () {
    logger.info('Updating youtubeDL binary.')

    const binDirectory = join(root(), 'node_modules', 'youtube-dl', 'bin')
    const bin = join(binDirectory, 'youtube-dl')
    const detailsPath = join(binDirectory, 'details')
    const url = process.env.YOUTUBE_DL_DOWNLOAD_HOST || 'https://yt-dl.org/downloads/latest/youtube-dl'

    await ensureDir(binDirectory)

    try {
      const gotContext = { bodyKBLimit: 20_000 }

      const result = await peertubeGot(url, { followRedirect: false, context: gotContext })

      if (result.statusCode !== HttpStatusCode.FOUND_302) {
        logger.error('youtube-dl update error: did not get redirect for the latest version link. Status %d', result.statusCode)
        return
      }

      const newUrl = result.headers.location
      const newVersion = /\/(\d{4}\.\d\d\.\d\d(\.\d)?)\/youtube-dl$/.exec(newUrl)[1]

      const downloadFileStream = peertubeGot.stream(newUrl, { context: gotContext })
      const writeStream = createWriteStream(bin, { mode: 493 })

      await pipelinePromise(
        downloadFileStream,
        writeStream
      )

      const details = JSON.stringify({ version: newVersion, path: bin, exec: 'youtube-dl' })
      await writeFile(detailsPath, details, { encoding: 'utf8' })

      logger.info('youtube-dl updated to version %s.', newVersion)
    } catch (err) {
      logger.error('Cannot update youtube-dl.', { err })
    }
  }

  static async safeGetYoutubeDL () {
    let youtubeDL

    try {
      youtubeDL = require('youtube-dl')
    } catch (e) {
      // Download binary
      await this.updateYoutubeDLBinary()
      youtubeDL = require('youtube-dl')
    }

    return youtubeDL
  }
}

// ---------------------------------------------------------------------------

export {
  YoutubeDL
}