frontend/src/context/ThemeContext.jsx

import { createContext, useContext, useEffect, useState } from 'react'

const ThemeContext = createContext()

export function ThemeProvider({ children }) {
  const [theme, setTheme] = useState(() => {
    return localStorage.getItem('theme') || 'dark'
  })

  useEffect(() => {
    localStorage.setItem('theme', theme)
    if (theme === 'light') {
      document.body.classList.add('light')
    } else {
      document.body.classList.remove('light')
    }
  }, [theme])

  const toggleTheme = () => setTheme((t) => (t === 'dark' ? 'light' : 'dark'))

  return (
    <ThemeContext.Provider value={{ theme, toggleTheme }}>
      {children}
    </ThemeContext.Provider>
  )
}

export function useTheme() {
  return useContext(ThemeContext)
}