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

const ThemeContext = createContext();

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

  useEffect(() => {
    const root = document.documentElement;
    const isLanding = window.location.pathname === '/';
    if (theme === 'dark' && !isLanding) {
      root.classList.add('dark');
    } else {
      root.classList.remove('dark');
    }
    localStorage.setItem('theme', theme);
  }, [theme]);

  const toggleTheme = () => {
    setTheme(prev => (prev === 'light' ? 'dark' : 'light'));
  };

  return (
    <ThemeContext.Provider value={{ theme, setTheme, toggleTheme, isDarkMode: theme === 'dark' }}>
      {children}
    </ThemeContext.Provider>
  );
};

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