import { mkdir, writeFile } from 'node:fs/promises'
import { extname, join } from 'node:path'
import { eq, sql } from 'drizzle-orm'
import { z } from 'zod'
import { commentAttachments, comments, uploads } from '../../../db/schema'
import { isAudioAttachment, isVideoAttachment, MAX_COMMENT_ATTACHMENTS } from '~~/shared/utils/attachments'

const bodySchema = z.object({
  content: z.string().trim().min(1).max(2000),
})

const attachmentsDir = () => join(uploadDir(), 'attachments')

export default defineEventHandler(async (event) => {
  const user = await requireUser(event)
  const id = getRouterParam(event, 'id') ?? ''
  if (!/^[A-Za-z0-9]{1,16}$/.test(id)) {
    throw createError({ statusCode: 400, statusMessage: 'Ungültige ID' })
  }
  const db = useDb()

  let content: string
  let files: { filename: string, type: string | undefined, data: Buffer, voice: boolean }[] = []

  if ((getRequestHeader(event, 'content-type') ?? '').includes('multipart/form-data')) {
    const parts = await readMultipartFormData(event)
    content = (parts?.find(p => p.name === 'content' && !p.filename)?.data.toString('utf8') ?? '').trim()
    files = (parts ?? [])
      .filter(p => (p.name === 'files' || p.name === 'voice') && p.filename && p.data?.length)
      .map(p => ({ filename: p.filename!, type: p.type, data: p.data, voice: p.name === 'voice' }))
    if (files.length > MAX_COMMENT_ATTACHMENTS) {
      throw createError({ statusCode: 400, statusMessage: `Maximal ${MAX_COMMENT_ATTACHMENTS} Anhänge pro Kommentar` })
    }
    if (files.some(f => f.data.length > MAX_UPLOAD_SIZE)) {
      throw createError({ statusCode: 413, statusMessage: 'Anhang ist zu groß (max. 200 MB)' })
    }
    if (!content && !files.length) {
      throw createError({ statusCode: 400, statusMessage: 'Kommentar darf nicht leer sein' })
    }
    if (content.length > 2000) {
      throw createError({ statusCode: 400, statusMessage: 'Kommentar ist zu lang (max. 2000 Zeichen)' })
    }
  }
  else {
    content = (await readValidatedBody(event, bodySchema.parse)).content
  }

  const exists = await db
    .select({ id: uploads.id })
    .from(uploads)
    .where(eq(uploads.id, id))
    .limit(1)
  if (!exists.length) {
    throw createError({ statusCode: 404, statusMessage: 'Upload nicht gefunden' })
  }

  const commentId = await db.transaction(async (tx) => {
    const [result] = await tx.insert(comments).values({ uploadId: id, userId: user.id, content })
    await ensureThreadSubscription(id, user.id, tx)
    return Number(result.insertId)
  })
  await db.update(uploads).set({ commentCount: sql`comment_count + 1` }).where(eq(uploads.id, id))

  const attachments: { id: number, name: string, url: string, mimeType: string | null, size: number, cover: string | null, meta: unknown }[] = []
  if (files.length) {
    await mkdir(attachmentsDir(), { recursive: true })
    for (const [i, file] of files.entries()) {
      let data = file.data
      let filename = file.filename
      let mimeType = (file.type || 'application/octet-stream').slice(0, 100)
      if (file.voice) {
        const mp3 = await transcodeVoiceToMp3(data)
        if (mp3) {
          data = mp3
          mimeType = 'audio/mpeg'
          filename = filename.replace(/\.[^./]+$/, '') + '.mp3'
        }
      }
      const ext = extname(filename).toLowerCase().replace(/[^a-z0-9.]/g, '').slice(0, 10)
      const storedName = `${commentId}-${i}${ext}`
      await writeFile(join(attachmentsDir(), storedName), data)
      const audioMeta = !file.voice && isAudioAttachment({ mimeType, name: filename })
        ? await extractAudioMeta(`att-${commentId}-${i}`, data, mimeType)
        : null
      const videoThumb = !file.voice && isVideoAttachment({ mimeType, name: filename })
        ? await extractVideoThumb(`att-${commentId}-${i}`, join(attachmentsDir(), storedName))
        : null
      const meta = file.voice ? { voice: true } : (audioMeta?.meta ?? null)
      const [row] = await db.insert(commentAttachments).values({
        commentId,
        fileName: storedName,
        originalName: filename.slice(0, 255),
        mimeType,
        size: data.length,
        cover: videoThumb ?? audioMeta?.cover ?? null,
        meta,
      })
      attachments.push({
        id: Number(row.insertId),
        name: filename.slice(0, 255),
        url: `/uploads/attachments/${storedName}`,
        mimeType,
        size: data.length,
        cover: videoThumb ?? audioMeta?.cover ?? null,
        meta,
      })
    }
  }

  const createdAt = new Date()
  broadcastToAll({
    type: 'comment',
    comment: {
      id: commentId,
      content,
      createdAt: createdAt.toISOString(),
      userName: user.name,
      userId: user.id,
      userColor: user.color,
      userAvatarUrl: avatarUrl(user.avatar),
      uploadId: id,
      attachments,
    },
  })
  await notifyComment(user.id, commentId, id, content || '[Anhang]')
  return {
    id: commentId,
    content,
    attachments,
    userName: user.name,
    createdAt: new Date(),
  }
})