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

type Theme = 'dark' | 'light';

interface ThemeContextType {
  theme: Theme;
  toggleTheme: () => void;
}

const ThemeContext = createContext<ThemeContextType | undefined>(undefined);

export function ThemeProvider({ children }: { children: React.ReactNode }) {
  const [theme, setTheme] = useState<Theme>('dark');

  useEffect(() => {
    const savedTheme = localStorage.getItem('portal_theme') as Theme | null;
    if (savedTheme === 'light' || savedTheme === 'dark') {
      setTheme(savedTheme);
      document.documentElement.setAttribute('data-theme', savedTheme);
    } else {
      document.documentElement.setAttribute('data-theme', 'dark');
    }
  }, []);

  const toggleTheme = () => {
    const newTheme = theme === 'dark' ? 'light' : 'dark';
    setTheme(newTheme);
    document.documentElement.setAttribute('data-theme', newTheme);
    localStorage.setItem('portal_theme', newTheme);
  };

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

export function useTheme() {
  const context = useContext(ThemeContext);
  if (!context) throw new Error('useTheme must be used within a ThemeProvider');
  return context;
}