export default defineWebSocketHandler({
  async open(peer) {
    const session = await getUserSession(peer) // read the cookie sent with the upgrade request
    if (!session.user) return peer.close(4001, 'Unauthorized')
    const boardId = new URL(peer.request.url).searchParams.get('board')!
    peer.context.user = session.user
    peer.subscribe(`board:${boardId}`)
    peer.publish(`board:${boardId}`, { type: 'presence', user: session.user.name, joined: true })
  },
  message(peer, message) {
    const event = JSON.parse(message.text()) as { type: 'move', cardId: string, column: string, version: number }
    if (event.type !== 'move') return
    // Persist, then broadcast with the authoritative version; the sender applies its own echo idempotently.
    const saved = moveCard(event.cardId, event.column)
    const boardId = new URL(peer.request.url).searchParams.get('board')!
    peer.publish(`board:${boardId}`, { ...event, version: saved.version, by: peer.context.user.id })
    peer.send({ ...event, version: saved.version, by: peer.context.user.id })
  },
  close(peer) {
    // subscriptions are dropped automatically; announce departure if you track presence
  },
})

export default defineNuxtConfig({ nitro: { experimental: { websocket: true } } })

import { useWebSocket } from '@vueuse/core'

interface Card { id: string, column: string, version: number }

export function useBoardSync(boardId: string, cards: Ref<Card[]>) {
  const url = computed(() => `${location.protocol === 'https:' ? 'wss' : 'ws'}://${location.host}/ws/board?board=${boardId}`)
  const { status, send } = useWebSocket(url, {
    autoReconnect: { retries: 10, delay: 1000 }, // add jitter for real deployments
    heartbeat: { message: 'ping', interval: 30_000 },
    onMessage(_ws, event) {
      const msg = JSON.parse(event.data) as { type: string, cardId?: string, column?: string, version?: number }
      if (msg.type !== 'move' || !msg.cardId) return
      const card = cards.value.find(c => c.id === msg.cardId)
      if (card && msg.version! > card.version) { // ignore stale or duplicate echoes
        card.column = msg.column!
        card.version = msg.version!
      }
    },
  })

  function move(cardId: string, column: string) {
    const card = cards.value.find(c => c.id === cardId)
    if (!card) return
    card.column = column // optimistic; the echo carries the authoritative version
    send(JSON.stringify({ type: 'move', cardId, column, version: card.version }))
  }

  return { status, move }
}

export default defineEventHandler(async (event) => {
  const id = getRouterParam(event, 'id')!
  const lastId = Number(getHeader(event, 'last-event-id') ?? 0)
  const stream = createEventStream(event)

  const unsubscribe = jobBus.subscribe(id, (update) => {
    if (update.seq <= lastId) return // the client already has it
    stream.push({ id: String(update.seq), event: 'progress', data: JSON.stringify(update) })
  })
  stream.onClosed(() => { unsubscribe(); stream.close() })
  return stream.send()
})

import { useEventSource } from '@vueuse/core'

export function useJobProgress(jobId: string) {
  const { data, status } = useEventSource(`/api/jobs/${jobId}/events`, ['progress'], { autoReconnect: true })
  const progress = computed(() => (data.value ? JSON.parse(data.value) as { seq: number, percent: number } : null))
  return { progress, status }
}