import { useCallback, useEffect, useState } from 'react'

import { getActiveEvSessions, type ActiveEvSessionRow } from '../api/backend'

const POLL_MS = 30_000

export function useEVSessions(siteId: number | null) {
  const [sessions, setSessions] = useState<ActiveEvSessionRow[]>([])
  const [ready, setReady] = useState(false)
  const [error, setError] = useState<string | null>(null)

  const load = useCallback(async () => {
    if (siteId == null) {
      setSessions([])
      setReady(true)
      return
    }
    try {
      const rows = await getActiveEvSessions(siteId)
      setSessions(rows)
      setError(null)
    } catch {
      setSessions([])
      setError('EV session se nepodařilo načíst')
    } finally {
      setReady(true)
    }
  }, [siteId])

  useEffect(() => {
    void load()
    if (siteId == null) return
    const id = window.setInterval(() => void load(), POLL_MS)
    return () => window.clearInterval(id)
  }, [load, siteId])

  return { sessions, ready, error, reload: load }
}