import { useState, useEffect } from 'react'

type Theme = 'dark' | 'light' | 'system'

export function useTheme() {
  const [theme, setTheme] = useState<Theme>(() => {
    return (localStorage.getItem('hive-theme') as Theme) || 'system'
  })

  useEffect(() => {
    const root = document.documentElement
    if (theme === 'system') {
      const prefersDark = window.matchMedia('(prefers-color-scheme: dark)').matches
      root.setAttribute('data-theme', prefersDark ? 'dark' : 'light')
    } else {
      root.setAttribute('data-theme', theme)
    }
    localStorage.setItem('hive-theme', theme)
  }, [theme])

  const toggle = () => setTheme(t => (t === 'dark' ? 'light' : 'dark'))
  return { theme, setTheme, toggle }
}