import express from 'express'
import { constants, promises as fs } from 'fs'
import { readFile } from 'fs-extra'
import { join } from 'path'
import { logger } from '@server/helpers/logger'
import { CONFIG } from '@server/initializers/config'
import { Hooks } from '@server/lib/plugins/hooks'
import { buildFileLocale, getCompleteLocale, is18nLocale, LOCALE_FILES } from '@shared/core-utils/i18n'
import { HttpStatusCode } from '@shared/models'
import { root } from '../helpers/core-utils'
import { STATIC_MAX_AGE } from '../initializers/constants'
import { ClientHtml, sendHTML, serveIndexHTML } from '../lib/client-html'
import { asyncMiddleware, disableRobots, embedCSP } from '../middlewares'

const clientsRouter = express.Router()

const distPath = join(root(), 'client', 'dist')
const testEmbedPath = join(distPath, 'standalone', 'videos', 'test-embed.html')

// Special route that add OpenGraph and oEmbed tags
// Do not use a template engine for a so little thing
clientsRouter.use([ '/w/p/:id', '/videos/watch/playlist/:id' ], asyncMiddleware(generateWatchPlaylistHtmlPage))
clientsRouter.use([ '/w/:id', '/videos/watch/:id' ], asyncMiddleware(generateWatchHtmlPage))
clientsRouter.use([ '/accounts/:nameWithHost', '/a/:nameWithHost' ], asyncMiddleware(generateAccountHtmlPage))
clientsRouter.use([ '/video-channels/:nameWithHost', '/c/:nameWithHost' ], asyncMiddleware(generateVideoChannelHtmlPage))
clientsRouter.use('/@:nameWithHost', asyncMiddleware(generateActorHtmlPage))

const embedMiddlewares = [
  CONFIG.CSP.ENABLED
    ? embedCSP
    : (req: express.Request, res: express.Response, next: express.NextFunction) => next(),

  // Set headers
  (req: express.Request, res: express.Response, next: express.NextFunction) => {
    res.removeHeader('X-Frame-Options')

    // Don't cache HTML file since it's an index to the immutable JS/CSS files
    res.setHeader('Cache-Control', 'public, max-age=0')

    next()
  },

  asyncMiddleware(generateEmbedHtmlPage)
]

clientsRouter.use('/videos/embed', ...embedMiddlewares)
clientsRouter.use('/video-playlists/embed', ...embedMiddlewares)

const testEmbedController = (req: express.Request, res: express.Response) => res.sendFile(testEmbedPath)

clientsRouter.use('/videos/test-embed', testEmbedController)
clientsRouter.use('/video-playlists/test-embed', testEmbedController)

// Dynamic PWA manifest
clientsRouter.get('/manifest.webmanifest', asyncMiddleware(generateManifest))

// Static client overrides
// Must be consistent with static client overrides redirections in /support/nginx/peertube
const staticClientOverrides = [
  'assets/images/logo.svg',
  'assets/images/favicon.png',
  'assets/images/icons/icon-36x36.png',
  'assets/images/icons/icon-48x48.png',
  'assets/images/icons/icon-72x72.png',
  'assets/images/icons/icon-96x96.png',
  'assets/images/icons/icon-144x144.png',
  'assets/images/icons/icon-192x192.png',
  'assets/images/icons/icon-512x512.png',
  'assets/images/default-playlist.jpg',
  'assets/images/default-avatar-account.png',
  'assets/images/default-avatar-video-channel.png'
]

for (const staticClientOverride of staticClientOverrides) {
  const overridePhysicalPath = join(CONFIG.STORAGE.CLIENT_OVERRIDES_DIR, staticClientOverride)
  clientsRouter.use(`/client/${staticClientOverride}`, asyncMiddleware(serveClientOverride(overridePhysicalPath)))
}

clientsRouter.use('/client/locales/:locale/:file.json', serveServerTranslations)
clientsRouter.use('/client', express.static(distPath, { maxAge: STATIC_MAX_AGE.CLIENT }))

// 404 for static files not found
clientsRouter.use('/client/*', (req: express.Request, res: express.Response) => {
  res.status(HttpStatusCode.NOT_FOUND_404).end()
})

// No index exceptions
clientsRouter.all('/about/peertube',
  disableRobots,
  asyncMiddleware(serveIndexHTML)
)

// Always serve index client page (the client is a single page application, let it handle routing)
// Try to provide the right language index.html
clientsRouter.use('/(:language)?', asyncMiddleware(serveIndexHTML))

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

export {
  clientsRouter
}

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

function serveServerTranslations (req: express.Request, res: express.Response) {
  const locale = req.params.locale
  const file = req.params.file

  if (is18nLocale(locale) && LOCALE_FILES.includes(file)) {
    const completeLocale = getCompleteLocale(locale)
    const completeFileLocale = buildFileLocale(completeLocale)

    const path = join(__dirname, `../../../client/dist/locale/${file}.${completeFileLocale}.json`)
    return res.sendFile(path, { maxAge: STATIC_MAX_AGE.SERVER })
  }

  return res.status(HttpStatusCode.NOT_FOUND_404).end()
}

async function generateEmbedHtmlPage (req: express.Request, res: express.Response) {
  const hookName = req.originalUrl.startsWith('/video-playlists/')
    ? 'filter:html.embed.video-playlist.allowed.result'
    : 'filter:html.embed.video.allowed.result'

  const allowParameters = { req }

  const allowedResult = await Hooks.wrapFun(
    isEmbedAllowed,
    allowParameters,
    hookName
  )

  if (!allowedResult || allowedResult.allowed !== true) {
    logger.info('Embed is not allowed.', { allowedResult })

    return sendHTML(allowedResult?.html || '', res)
  }

  const html = await ClientHtml.getEmbedHTML()

  return sendHTML(html, res)
}

async function generateWatchHtmlPage (req: express.Request, res: express.Response) {
  const html = await ClientHtml.getWatchHTMLPage(req.params.id + '', req, res)

  return sendHTML(html, res)
}

async function generateWatchPlaylistHtmlPage (req: express.Request, res: express.Response) {
  const html = await ClientHtml.getWatchPlaylistHTMLPage(req.params.id + '', req, res)

  return sendHTML(html, res)
}

async function generateAccountHtmlPage (req: express.Request, res: express.Response) {
  const html = await ClientHtml.getAccountHTMLPage(req.params.nameWithHost, req, res)

  return sendHTML(html, res)
}

async function generateVideoChannelHtmlPage (req: express.Request, res: express.Response) {
  const html = await ClientHtml.getVideoChannelHTMLPage(req.params.nameWithHost, req, res)

  return sendHTML(html, res)
}

async function generateActorHtmlPage (req: express.Request, res: express.Response) {
  const html = await ClientHtml.getActorHTMLPage(req.params.nameWithHost, req, res)

  return sendHTML(html, res)
}

async function generateManifest (req: express.Request, res: express.Response) {
  const manifestPhysicalPath = join(root(), 'client', 'dist', 'manifest.webmanifest')
  const manifestJson = await readFile(manifestPhysicalPath, 'utf8')
  const manifest = JSON.parse(manifestJson)

  manifest.name = CONFIG.INSTANCE.NAME
  manifest.short_name = CONFIG.INSTANCE.NAME
  manifest.description = CONFIG.INSTANCE.SHORT_DESCRIPTION

  res.json(manifest)
}

function serveClientOverride (path: string) {
  return async (req: express.Request, res: express.Response, next: express.NextFunction) => {
    try {
      await fs.access(path, constants.F_OK)
      // Serve override client
      res.sendFile(path, { maxAge: STATIC_MAX_AGE.SERVER })
    } catch {
      // Serve dist client
      next()
    }
  }
}

type AllowedResult = { allowed: boolean, html?: string }
function isEmbedAllowed (_object: {
  req: express.Request
}): AllowedResult {
  return { allowed: true }
}