import { forceNumber, maxBy } from '@peertube/peertube-core-utils'
import { FileStorage, HttpStatusCode, VideoResolution, VideoStreamingPlaylistType } from '@peertube/peertube-models'
import { exists } from '@server/helpers/custom-validators/misc.js'
import { logger, loggerTagsFactory } from '@server/helpers/logger.js'
import { CONFIG } from '@server/initializers/config.js'
import { VideoTorrentsSimpleFileCache } from '@server/lib/files-cache/index.js'
import {
  generateHLSFilePresignedUrl,
  generateOriginalFilePresignedUrl,
  generateUserExportPresignedUrl,
  generateWebVideoPresignedUrl
} from '@server/lib/object-storage/index.js'
import { getFSUserExportFilePath } from '@server/lib/paths.js'
import { Hooks } from '@server/lib/plugins/hooks.js'
import { VideoDownload } from '@server/lib/video-download.js'
import { VideoPathManager } from '@server/lib/video-path-manager.js'
import {
  MStreamingPlaylist,
  MStreamingPlaylistVideo,
  MUserExport,
  MVideo,
  MVideoFile,
  MVideoFullLight
} from '@server/types/models/index.js'
import { MVideoSource } from '@server/types/models/video/video-source.js'
import cors from 'cors'
import express from 'express'
import { DOWNLOAD_PATHS, WEBSERVER } from '../initializers/constants.js'
import {
  asyncMiddleware,
  buildRateLimiter,
  optionalAuthenticate,
  originalVideoFileDownloadValidator,
  userExportDownloadValidator,
  videosDownloadValidator,
  videosGenerateDownloadValidator
} from '../middlewares/index.js'

const lTags = loggerTagsFactory('download')

const downloadRouter = express.Router()

downloadRouter.use(cors())

downloadRouter.use(
  DOWNLOAD_PATHS.TORRENTS + ':filename',
  asyncMiddleware(downloadTorrent)
)

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

downloadRouter.use(
  DOWNLOAD_PATHS.WEB_VIDEOS + ':id-:resolution([0-9]+).:extension',
  optionalAuthenticate,
  asyncMiddleware(videosDownloadValidator),
  asyncMiddleware(downloadWebVideoFile)
)

downloadRouter.use(
  DOWNLOAD_PATHS.HLS_VIDEOS + ':id-:resolution([0-9]+)-fragmented.:extension',
  optionalAuthenticate,
  asyncMiddleware(videosDownloadValidator),
  asyncMiddleware(downloadHLSVideoFile)
)

const downloadGenerateRateLimiter = buildRateLimiter({
  windowMs: CONFIG.RATES_LIMIT.DOWNLOAD_GENERATE_VIDEO.WINDOW_MS,
  max: CONFIG.RATES_LIMIT.DOWNLOAD_GENERATE_VIDEO.MAX,
  skipFailedRequests: true
})

downloadRouter.use(
  [ DOWNLOAD_PATHS.GENERATE_VIDEO + ':id.m4a', DOWNLOAD_PATHS.GENERATE_VIDEO + ':id.mp4', DOWNLOAD_PATHS.GENERATE_VIDEO + ':id' ],
  downloadGenerateRateLimiter,
  optionalAuthenticate,
  asyncMiddleware(videosDownloadValidator),
  videosGenerateDownloadValidator,
  asyncMiddleware(downloadGeneratedVideoFile)
)

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

downloadRouter.use(
  DOWNLOAD_PATHS.USER_EXPORTS + ':filename',
  asyncMiddleware(userExportDownloadValidator), // Include JWT token authentication
  asyncMiddleware(downloadUserExport)
)

downloadRouter.use(
  DOWNLOAD_PATHS.ORIGINAL_VIDEO_FILE + ':filename',
  optionalAuthenticate,
  asyncMiddleware(originalVideoFileDownloadValidator),
  asyncMiddleware(downloadOriginalFile)
)

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

export {
  downloadRouter
}

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

async function downloadTorrent (req: express.Request, res: express.Response) {
  const result = await VideoTorrentsSimpleFileCache.Instance.getFilePath(req.params.filename)
  if (!result) {
    return res.fail({
      status: HttpStatusCode.NOT_FOUND_404,
      message: 'Torrent file not found'
    })
  }

  const allowParameters = {
    req,
    res,
    torrentPath: result.path,
    downloadName: result.downloadName
  }

  const allowedResult = await Hooks.wrapFun(
    isTorrentDownloadAllowed,
    allowParameters,
    'filter:api.download.torrent.allowed.result'
  )

  if (!checkAllowResult(res, allowParameters, allowedResult)) return

  return res.download(result.path, result.downloadName)
}

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

async function downloadWebVideoFile (req: express.Request, res: express.Response) {
  const video = res.locals.videoAll

  const videoFile = getVideoFileFromReq(req, video.VideoFiles)
  if (!videoFile) {
    return res.fail({
      status: HttpStatusCode.NOT_FOUND_404,
      message: 'Video file not found'
    })
  }

  const allowParameters = {
    req,
    res,
    video,
    videoFile
  }

  const allowedResult = await Hooks.wrapFun(
    isVideoDownloadAllowed,
    allowParameters,
    'filter:api.download.video.allowed.result'
  )

  if (!checkAllowResult(res, allowParameters, allowedResult)) return

  const downloadFilename = buildDownloadFilename({ video, resolution: videoFile.resolution, extname: videoFile.extname })

  if (videoFile.storage === FileStorage.OBJECT_STORAGE) {
    return redirectVideoDownloadToObjectStorage({ res, video, file: videoFile, downloadFilename })
  }

  await VideoPathManager.Instance.makeAvailableVideoFile(videoFile.withVideoOrPlaylist(video), path => {
    return res.download(path, downloadFilename)
  })
}

async function downloadHLSVideoFile (req: express.Request, res: express.Response) {
  const video = res.locals.videoAll
  const streamingPlaylist = getHLSPlaylist(video)
  if (!streamingPlaylist) return res.sendStatus(HttpStatusCode.NOT_FOUND_404)

  const videoFile = getVideoFileFromReq(req, streamingPlaylist.VideoFiles)
  if (!videoFile) {
    return res.fail({
      status: HttpStatusCode.NOT_FOUND_404,
      message: 'Video file not found'
    })
  }

  const allowParameters = {
    req,
    res,
    video,
    streamingPlaylist,
    videoFile
  }

  const allowedResult = await Hooks.wrapFun(
    isVideoDownloadAllowed,
    allowParameters,
    'filter:api.download.video.allowed.result'
  )

  if (!checkAllowResult(res, allowParameters, allowedResult)) return

  const downloadFilename = buildDownloadFilename({ video, streamingPlaylist, resolution: videoFile.resolution, extname: videoFile.extname })

  if (videoFile.storage === FileStorage.OBJECT_STORAGE) {
    return redirectVideoDownloadToObjectStorage({ res, video, streamingPlaylist, file: videoFile, downloadFilename })
  }

  await VideoPathManager.Instance.makeAvailableVideoFile(videoFile.withVideoOrPlaylist(streamingPlaylist), path => {
    return res.download(path, downloadFilename)
  })
}

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

async function downloadGeneratedVideoFile (req: express.Request, res: express.Response) {
  const video = res.locals.videoAll
  const filesToSelect = req.query.videoFileIds

  const videoFiles = video.getAllFiles()
    .filter(f => filesToSelect.includes(f.id))

  if (videoFiles.length === 0) {
    return res.fail({
      status: HttpStatusCode.NOT_FOUND_404,
      message: `No files found (${filesToSelect.join(', ')}) to download video ${video.url}`
    })
  }

  if (videoFiles.filter(f => f.hasVideo()).length > 1 || videoFiles.filter(f => f.hasAudio()).length > 1) {
    return res.fail({
      status: HttpStatusCode.BAD_REQUEST_400,
      // In theory we could, but ffmpeg-fluent doesn't support multiple input streams so prefer to reject this specific use case
      message: `Cannot generate a container with multiple video/audio files. PeerTube supports a maximum of 1 audio and 1 video file`
    })
  }

  const allowParameters = {
    req,
    res,
    video,
    videoFiles
  }

  const allowedResult = await Hooks.wrapFun(
    isGeneratedVideoDownloadAllowed,
    allowParameters,
    'filter:api.download.generated-video.allowed.result'
  )

  if (!checkAllowResult(res, allowParameters, allowedResult)) return

  if (VideoDownload.totalDownloads > CONFIG.DOWNLOAD_GENERATE_VIDEO.MAX_PARALLEL_DOWNLOADS) {
    return res.fail({
      status: HttpStatusCode.TOO_MANY_REQUESTS_429,
      message: `Too many parallel downloads on this server. Please try again later.`
    })
  }

  const maxResolutionFile = maxBy(videoFiles, 'resolution')

  // Prefer m4a extension for the user if this is a mp4 audio file only
  const extname = maxResolutionFile.resolution === VideoResolution.H_NOVIDEO && maxResolutionFile.extname === '.mp4'
    ? '.m4a'
    : maxResolutionFile.extname

  // If there is the extension, we want to simulate a "raw file" and so not send the content disposition header
  const urlPath = new URL(req.originalUrl, WEBSERVER.URL).pathname
  if (!urlPath.endsWith('.mp4') && !urlPath.endsWith('.m4a')) {
    const downloadFilename = buildDownloadFilename({ video, extname })
    res.setHeader('Content-disposition', `attachment; filename="${encodeURI(downloadFilename)}`)
  }

  res.type(extname)

  await new VideoDownload({ video, videoFiles }).muxToMergeVideoFiles(res)
}

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

function downloadUserExport (req: express.Request, res: express.Response) {
  const userExport = res.locals.userExport

  const downloadFilename = userExport.filename

  if (userExport.storage === FileStorage.OBJECT_STORAGE) {
    return redirectUserExportToObjectStorage({ res, userExport, downloadFilename })
  }

  res.download(getFSUserExportFilePath(userExport), downloadFilename)
  return Promise.resolve()
}

function downloadOriginalFile (req: express.Request, res: express.Response) {
  const videoSource = res.locals.videoSource

  const downloadFilename = videoSource.inputFilename

  if (videoSource.storage === FileStorage.OBJECT_STORAGE) {
    return redirectOriginalFileToObjectStorage({ res, videoSource, downloadFilename })
  }

  res.download(VideoPathManager.Instance.getFSOriginalVideoFilePath(videoSource.keptOriginalFilename), downloadFilename)
  return Promise.resolve()
}

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

function getVideoFileFromReq (req: express.Request, files: MVideoFile[]) {
  const resolution = forceNumber(req.params.resolution)
  return files.find(f => f.resolution === resolution)
}

function getHLSPlaylist (video: MVideoFullLight) {
  const playlist = video.VideoStreamingPlaylists.find(p => p.type === VideoStreamingPlaylistType.HLS)
  if (!playlist) return undefined

  return Object.assign(playlist, { Video: video })
}

type AllowedResult = {
  allowed: boolean
  errorMessage?: string
}

function isTorrentDownloadAllowed (_object: {
  torrentPath: string
}): AllowedResult {
  return { allowed: true }
}

function isVideoDownloadAllowed (_object: {
  video: MVideo
  videoFile: MVideoFile
  streamingPlaylist?: MStreamingPlaylist
}): AllowedResult {
  return { allowed: true }
}

function isGeneratedVideoDownloadAllowed (_object: {
  video: MVideo
  videoFiles: MVideoFile[]
}): AllowedResult {
  return { allowed: true }
}

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

function checkAllowResult (res: express.Response, allowParameters: any, result?: AllowedResult) {
  if (!result || result.allowed !== true) {
    logger.info('Download is not allowed.', { result, allowParameters, ...lTags() })

    res.fail({
      status: HttpStatusCode.FORBIDDEN_403,
      message: result?.errorMessage || 'Refused download'
    })
    return false
  }

  return true
}

async function redirectVideoDownloadToObjectStorage (options: {
  res: express.Response
  video: MVideo
  file: MVideoFile
  streamingPlaylist?: MStreamingPlaylistVideo
  downloadFilename: string
}) {
  const { res, video, streamingPlaylist, file, downloadFilename } = options

  const url = streamingPlaylist
    ? await generateHLSFilePresignedUrl({ streamingPlaylist, file, downloadFilename })
    : await generateWebVideoPresignedUrl({ file, downloadFilename })

  logger.debug('Generating pre-signed URL %s for video %s', url, video.uuid, lTags())

  return res.redirect(url)
}

async function redirectUserExportToObjectStorage (options: {
  res: express.Response
  downloadFilename: string
  userExport: MUserExport
}) {
  const { res, downloadFilename, userExport } = options

  const url = await generateUserExportPresignedUrl({ userExport, downloadFilename })

  logger.debug('Generating pre-signed URL %s for user export %s', url, userExport.filename, lTags())

  return res.redirect(url)
}

async function redirectOriginalFileToObjectStorage (options: {
  res: express.Response
  downloadFilename: string
  videoSource: MVideoSource
}) {
  const { res, downloadFilename, videoSource } = options

  const url = await generateOriginalFilePresignedUrl({ videoSource, downloadFilename })

  logger.debug('Generating pre-signed URL %s for original video file %s', url, videoSource.keptOriginalFilename, lTags())

  return res.redirect(url)
}

function buildDownloadFilename (options: {
  video: MVideo
  streamingPlaylist?: MStreamingPlaylist
  resolution?: number
  extname: string
}) {
  const { video, resolution, extname, streamingPlaylist } = options

  // Express uses basename on filename parameter
  const videoName = video.name.replace(/[/\\]/g, '_')

  const suffixStr = streamingPlaylist
    ? `-${streamingPlaylist.getStringType()}`
    : ''

  const resolutionStr = exists(resolution)
    ? `-${resolution}p`
    : ''

  return videoName + resolutionStr + suffixStr + extname
}
