import { and, desc, eq } from 'drizzle-orm'
import { favorites, threadSubscriptions, uploads, users } from '../../../db/schema'

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()

  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 existing = await db
    .select()
    .from(favorites)
    .where(and(eq(favorites.uploadId, id), eq(favorites.userId, user.id)))
    .limit(1)

  if (existing.length) {
    await db.delete(favorites).where(and(eq(favorites.uploadId, id), eq(favorites.userId, user.id)))
  }
  else {
    await db.transaction(async (tx) => {
      await tx.insert(favorites).values({ uploadId: id, userId: user.id })
      await ensureThreadSubscription(id, user.id, tx)
    })
  }

  const favRows = await db
    .select({ id: users.id, name: users.name, color: users.color, avatar: users.avatar })
    .from(favorites)
    .innerJoin(users, eq(favorites.userId, users.id))
    .where(eq(favorites.uploadId, id))
    .orderBy(desc(favorites.createdAt))

  const [subscription] = await db.select({ enabled: threadSubscriptions.enabled }).from(threadSubscriptions)
    .where(and(eq(threadSubscriptions.uploadId, id), eq(threadSubscriptions.userId, user.id))).limit(1)
  return {
    isSubscribed: subscription?.enabled ?? false,
    favorited: !existing.length,
    favoritedBy: favRows.map(f => ({ id: f.id, name: f.name, color: f.color, avatarUrl: avatarUrl(f.avatar) })),
  }
})