import { and, count, desc, eq, max } from 'drizzle-orm'
import { comments, notifications, uploads, users } from '../../db/schema'
import { mentionedUserIds } from '../../../shared/utils/mentions'

export default defineEventHandler(async (event) => {
  const user = await getSessionUser(event)
  if (!user) {
    return { notifications: [], unreadCount: 0 }
  }
  const db = useDb()
  const threads = db.select({ id: max(notifications.id).as('thread_notification_id') }).from(notifications)
    .where(and(eq(notifications.userId, user.id), eq(notifications.isRead, false)))
    .groupBy(notifications.uploadId).as('thread_notifications')
  const [total] = await db.select({ count: count() }).from(threads)
  const rows = await db
    .select({
      id: notifications.id,
      uploadId: notifications.uploadId,
      commentId: notifications.commentId,
      isRead: notifications.isRead,
      createdAt: notifications.createdAt,
      actorName: users.name,
      actorColor: users.color,
      content: comments.content,
      uploadType: uploads.type,
      fileName: uploads.fileName,
      externalUrl: uploads.externalUrl,
      previewImage: uploads.previewImage,
    })
    .from(notifications)
    .innerJoin(threads, eq(notifications.id, threads.id))
    .innerJoin(users, eq(notifications.actorId, users.id))
    .innerJoin(comments, eq(notifications.commentId, comments.id))
    .innerJoin(uploads, eq(notifications.uploadId, uploads.id))
    .where(and(eq(notifications.userId, user.id), eq(notifications.isRead, false)))
    .orderBy(desc(notifications.createdAt), desc(notifications.id))
    .limit(30)
  const mentionUsers = rows.some(row => row.content.includes('@'))
    ? await db.select({ id: users.id, name: users.name, color: users.color }).from(users)
    : []
  return {
    notifications: rows.map((row) => {
      const url = row.externalUrl ?? `/uploads/${row.fileName}`
      const embedId = row.uploadType === 'youtube' && row.externalUrl ? getYoutubeId(row.externalUrl) : null
      const thumbUrl = row.uploadType === 'youtube' && embedId
        ? youtubeThumbUrl(embedId)
        : row.uploadType === 'image' ? url : row.uploadType === 'link' ? row.previewImage : null
      return { ...row, url, thumbUrl, isMention: mentionedUserIds(row.content, mentionUsers).has(user.id) }
    }),
    unreadCount: Number(total?.count ?? 0),
  }
})