// Global refresh rate: one setting for every live view. Kept in localStorage for instant
// use and mirrored to the hub's UI prefs so it follows the login.
import { useEffect, useState } from 'react'

export const REFRESH_OPTIONS = [250, 500, 1000, 2000, 5000] as const
export const DEFAULT_REFRESH = 2000
// No floors: the rate means exactly what it says on every page, at the host's expense.
export const LIST_FLOOR = 0
const KEY = 'hamlab.refresh'

export function getRefreshMs(): number {
  const v = Number(localStorage.getItem(KEY))
  return v >= 100 && v <= 60000 ? v : DEFAULT_REFRESH
}

export function setRefreshMs(ms: number) {
  if (!(ms >= 100 && ms <= 60000)) return // never accept a nonsense rate, wherever it came from
  localStorage.setItem(KEY, String(ms))
  window.dispatchEvent(new CustomEvent('hamlab:refresh', { detail: ms }))
}

export function fmtMs(ms: number): string { return ms >= 1000 ? `${ms / 1000} s` : `${ms} ms` }

// useRefreshMs re-renders the caller when the global rate changes.
export function useRefreshMs(floor = 0): number {
  const [ms, setMs] = useState(getRefreshMs())
  useEffect(() => {
    const h = (e: Event) => setMs((e as CustomEvent<number>).detail)
    window.addEventListener('hamlab:refresh', h)
    return () => window.removeEventListener('hamlab:refresh', h)
  }, [])
  return Math.max(ms, floor)
}