"use client";

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

type Theme = 'light' | 'dark';

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

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

export const ThemeProvider: React.FC<{ children: React.ReactNode }> = ({ children }) => {
  const [theme, setThemeState] = useState<Theme>('light');
  const [mounted, setMounted] = useState(false);

  useEffect(() => {
    setMounted(true);
    // Get theme from localStorage or default to 'light'
    const savedTheme = localStorage.getItem('theme') as Theme;
    if (savedTheme) {
      setThemeState(savedTheme);
    } else {
      // Check system preference
      const systemTheme = window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light';
      setThemeState(systemTheme);
    }
  }, []);

  useEffect(() => {
    if (!mounted) return;
    
    // Update document class and localStorage
    document.documentElement.classList.remove('light', 'dark');
    document.documentElement.classList.add(theme);
    localStorage.setItem('theme', theme);
  }, [theme, mounted]);

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

  const setTheme = (newTheme: Theme) => {
    setThemeState(newTheme);
  };

  // Prevent hydration mismatch
  if (!mounted) {
    return <>{children}</>;
  }

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

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