import express, { Router } from 'express'
import { getSessionCustomerId, requireSession } from '../middleware/session.js'
import { assertOwnProject, getFeatureDoc } from '../services/siteFeatures.js'
import { NEWS_IMAGE_MAX_BYTES, newsImagePath, newsImageRateLimited, storeNewsImage } from '../services/newsImages.js'
import { createPost, deletePost, listPosts, updatePost } from '../services/newsPosts.js'
import { uploadSlot } from './chat.js'

const router = Router()

const HOUR_MS = 60 * 60 * 1000
const MAX_WRITES_PER_HOUR = 30
const IMAGE_FILE_RE = /^([a-z0-9-]+)-(l|s)\.webp$/

function fail(res, err) {
  const status = err.status >= 400 && err.status < 600 ? err.status : 500
  if (status >= 500) console.error('[news]', err.message)
  const body = { error: status >= 500 ? 'Interner Serverfehler' : err.message }
  if (err.field) body.field = err.field
  return res.status(status).json(body)
}

// Schreib-Limit je Kunde und Stunde (im Speicher, wie beim Chat); zaehlt POST/PATCH/DELETE, nicht die Foto-Uploads
const recentWrites = new Map()
function writeRateLimited(customerId) {
  const now = Date.now()
  for (const [key, times] of recentWrites) {
    const live = times.filter((t) => now - t < HOUR_MS)
    if (live.length === 0) recentWrites.delete(key)
    else if (live.length !== times.length) recentWrites.set(key, live)
  }
  const list = recentWrites.get(customerId) || []
  list.push(now)
  recentWrites.set(customerId, list)
  return list.length > MAX_WRITES_PER_HOUR
}

function rejectViewAs(req, res, next) {
  if (req.session.viewAs) {
    return res.status(403).json({ error: 'Im "Als Kunde ansehen"-Modus kann nichts geändert werden.' })
  }
  return next()
}

function limitWrites(req, res, next) {
  if (writeRateLimited(getSessionCustomerId(req))) {
    return res.status(429).json({ error: 'Zu viele Änderungen in kurzer Zeit. Bitte versuch es in einer Stunde wieder.' })
  }
  return next()
}

const projectIdOf = (req) => {
  const raw = req.query.projectId ?? req.body?.projectId
  return typeof raw === 'string' ? raw : ''
}

/** Eigenes Projekt pruefen (req.projectId, req.project); mit requireActive zusaetzlich die News-Funktion. */
const withProject = ({ requireActive = true } = {}) => async (req, res, next) => {
  try {
    const projectId = projectIdOf(req)
    if (!projectId) return res.status(400).json({ error: 'Bitte wähle ein Projekt.' })
    const customerId = getSessionCustomerId(req)
    req.project = await assertOwnProject(customerId, projectId)
    req.projectId = projectId
    if (requireActive) {
      const feature = await getFeatureDoc(customerId, projectId, 'news')
      if (feature?.state !== 'active') {
        return res.status(409).json({ error: 'News ist für diese Website nicht aktiv.' })
      }
    }
    return next()
  } catch (err) {
    return fail(res, err)
  }
}

router.get('/', requireSession, withProject(), async (req, res) => {
  try {
    const { hanging, expired } = await listPosts(req.projectId)
    res.json({ hanging, expired, liveUrl: req.project.liveDomain ? `https://${req.project.liveDomain}` : '' })
  } catch (err) {
    fail(res, err)
  }
})

router.post('/', requireSession, rejectViewAs, withProject(), limitWrites, async (req, res) => {
  try {
    const post = await createPost({ customerId: getSessionCustomerId(req), projectId: req.projectId, input: req.body })
    res.status(201).json(post)
  } catch (err) {
    fail(res, err)
  }
})

// Foto als rohe Bytes (application/octet-stream), hoechstens 10 MB
router.post(
  '/image',
  requireSession,
  rejectViewAs,
  withProject(),
  (req, res, next) => {
    if (newsImageRateLimited(getSessionCustomerId(req))) {
      return res.status(429).json({ error: 'Zu viele Fotos in kurzer Zeit. Bitte versuch es später wieder.' })
    }
    return next()
  },
  uploadSlot,
  express.raw({ type: 'application/octet-stream', limit: NEWS_IMAGE_MAX_BYTES }),
  async (req, res) => {
    try {
      const image = await storeNewsImage({ customerId: getSessionCustomerId(req), projectId: req.projectId, buffer: req.body })
      res.status(201).json(image)
    } catch (err) {
      fail(res, err)
    }
  }
)

// Vorschau im Editor: nur fuer den Kunden, dem das Projekt gehoert
router.get('/image/:projectId/:file', requireSession, async (req, res) => {
  try {
    await assertOwnProject(getSessionCustomerId(req), req.params.projectId)
    const match = IMAGE_FILE_RE.exec(req.params.file)
    const file = match && newsImagePath(req.params.projectId, match[1], match[2])
    if (!file) return res.status(404).json({ error: 'Foto nicht gefunden.' })
    res.set({ 'Cache-Control': 'private, max-age=3600', 'X-Content-Type-Options': 'nosniff' })
    return res.sendFile(file, (err) => {
      if (err && !res.headersSent) res.status(404).json({ error: 'Foto nicht gefunden.' })
    })
  } catch (err) {
    return fail(res, err)
  }
})

router.patch('/:id', requireSession, rejectViewAs, withProject(), limitWrites, async (req, res) => {
  try {
    const post = await updatePost({ customerId: getSessionCustomerId(req), projectId: req.projectId, id: req.params.id, input: req.body })
    res.json(post)
  } catch (err) {
    fail(res, err)
  }
})

router.delete('/:id', requireSession, rejectViewAs, withProject(), limitWrites, async (req, res) => {
  try {
    await deletePost({ customerId: getSessionCustomerId(req), projectId: req.projectId, id: req.params.id })
    res.status(204).end()
  } catch (err) {
    fail(res, err)
  }
})

// Zu grosse Fotos verstaendlich melden
router.use((err, _req, res, next) => {
  if (err?.type === 'entity.too.large') return res.status(413).json({ error: 'Das Foto ist größer als 10 MB.' })
  if (err?.type === 'request.aborted') return res.status(400).end()
  return next(err)
})

export default router