import { mkdir, writeFile } from 'node:fs/promises'
import { basename, extname, join } from 'node:path'
import { z } from 'zod'
import { uploads } from '../../db/schema'

const MAX_SIZE = MAX_UPLOAD_SIZE

const MIME_EXT: Record<string, string> = {
  'image/jpeg': '.jpg',
  'image/png': '.png',
  'image/gif': '.gif',
  'image/webp': '.webp',
  'image/avif': '.avif',
  'video/mp4': '.mp4',
  'video/webm': '.webm',
  'video/quicktime': '.mov',
  'audio/mpeg': '.mp3',
  'audio/mp3': '.mp3',
  'audio/flac': '.flac',
  'audio/x-flac': '.flac',
}

// Fallback, wenn der Browser keinen MIME-Type mitschickt
const EXT_MIME: Record<string, string> = {
  '.jpg': 'image/jpeg',
  '.jpeg': 'image/jpeg',
  '.png': 'image/png',
  '.gif': 'image/gif',
  '.webp': 'image/webp',
  '.avif': 'image/avif',
  '.svg': 'image/svg+xml',
  '.mp4': 'video/mp4',
  '.webm': 'video/webm',
  '.mov': 'video/quicktime',
  '.mp3': 'audio/mpeg',
  '.flac': 'audio/flac',
}

const urlSchema = z.object({
  url: z.url().max(2048),
})

export default defineEventHandler(async (event) => {
  const user = await requireUser(event)
  const db = useDb()

  if ((getRequestHeader(event, 'content-type') ?? '').includes('application/json')) {
    const body = await readValidatedBody(event, urlSchema.parse)
    if (!/^https?:\/\//i.test(body.url)) {
      throw createError({ statusCode: 400, statusMessage: 'Nur http(s)-URLs erlaubt' })
    }
    const type = classifyUrl(body.url)
    const id = await newUploadId(db)

    // Direkte Bild-/Video-URLs werden heruntergeladen und lokal gespeichert,
    // als wäre die Datei direkt hochgeladen worden
    if (type === 'image' || type === 'video' || type === 'audio') {
      const media = await downloadExternalMedia(body.url)
      const urlExt = extname(new URL(body.url).pathname).toLowerCase().replace(/[^a-z0-9.]/g, '').slice(0, 10)
      const ext = MIME_EXT[media.mimeType] ?? urlExt
      const fileName = `${id}${ext}`
      await mkdir(uploadDir(), { recursive: true })
      await writeFile(join(uploadDir(), fileName), media.data)
      const audioMeta = media.type === 'audio'
        ? await extractAudioMeta(id, media.data, media.mimeType)
        : null
      const videoThumb = media.type === 'video'
        ? await extractVideoThumb(id, join(uploadDir(), fileName))
        : null
      await db.insert(uploads).values({
        id,
        userId: user.id,
        type: media.type,
        fileName,
        originalName: decodeURIComponent(basename(new URL(body.url).pathname) || body.url).slice(0, 255),
        mimeType: media.mimeType.slice(0, 100),
        size: media.data.length,
        previewImage: videoThumb ?? audioMeta?.cover ?? null,
        audioMeta: audioMeta?.meta ?? null,
      })
      await ensureThreadSubscription(id, user.id)
      return { id, type: media.type, url: `/uploads/${fileName}` }
    }

    const twitchTarget = type === 'twitch' ? getTwitchTarget(body.url) : null
    const [preview, twitchPreview] = await Promise.all([
      type === 'link' || type === 'twitch' ? fetchLinkPreview(body.url) : null,
      twitchTarget ? fetchTwitchPreview(twitchTarget) : null,
    ])
    const embedId = type === 'youtube' ? getYoutubeId(body.url) : null
    const remotePreviewImage = twitchPreview?.image ?? preview?.image
      ?? (embedId ? youtubeThumbUrl(embedId) : null)
    const previewImage = remotePreviewImage
      ? (await savePreviewImage(id, remotePreviewImage)) ?? remotePreviewImage
      : null
    await db.insert(uploads).values({
      id,
      userId: user.id,
      type,
      externalUrl: body.url,
      originalName: body.url.slice(0, 255),
      previewImage,
      previewTitle: twitchPreview?.title ?? preview?.title ?? null,
    })
    await ensureThreadSubscription(id, user.id)
    return { id, type, url: body.url }
  }

  const parts = await readMultipartFormData(event)
  const file = parts?.find(p => p.name === 'file')

  if (!file?.data?.length) {
    throw createError({ statusCode: 400, statusMessage: 'Keine Datei hochgeladen' })
  }

  // Manche Formate kommen ohne MIME-Type (z. B. .flac) — dann per Endung klassifizieren
  const fileExt = extname(file.filename ?? '').toLowerCase()
  const rawMime = file.type ?? ''
  const mimeType = rawMime && rawMime !== 'application/octet-stream' ? rawMime : (EXT_MIME[fileExt] ?? rawMime)
  const type = mimeType.startsWith('image/') ? 'image'
    : mimeType.startsWith('video/') ? 'video'
      : mimeType.startsWith('audio/') ? 'audio'
        : IMAGE_EXT.test(fileExt) ? 'image'
          : VIDEO_EXT.test(fileExt) ? 'video'
            : AUDIO_EXT.test(fileExt) ? 'audio'
              : null
  if (!type) {
    throw createError({ statusCode: 415, statusMessage: 'Nur Bilder, Videos und Audiodateien sind erlaubt' })
  }
  if (file.data.length > MAX_SIZE) {
    throw createError({ statusCode: 413, statusMessage: 'Datei ist zu groß (max. 200 MB)' })
  }

  const ext = MIME_EXT[mimeType]
    ?? fileExt.replace(/[^a-z0-9.]/g, '').slice(0, 10)
    ?? ''
  const id = await newUploadId(db)
  const fileName = `${id}${ext}`

  await mkdir(uploadDir(), { recursive: true })
  await writeFile(join(uploadDir(), fileName), file.data)
  const audioMeta = type === 'audio'
    ? await extractAudioMeta(id, file.data, mimeType)
    : null
  const videoThumb = type === 'video'
    ? await extractVideoThumb(id, join(uploadDir(), fileName))
    : null
  await db.insert(uploads).values({
    id,
    userId: user.id,
    type,
    fileName,
    originalName: (file.filename ?? fileName).slice(0, 255),
    mimeType: (mimeType || 'application/octet-stream').slice(0, 100),
    size: file.data.length,
    previewImage: videoThumb ?? audioMeta?.cover ?? null,
    audioMeta: audioMeta?.meta ?? null,
  })

  await ensureThreadSubscription(id, user.id)
  return {
    id,
    type,
    url: `/uploads/${fileName}`,
  }
})