'use client';

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

type Theme = 'light' | 'dark';

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

const ThemeContext = createContext<ThemeContextType>({
  theme: 'light',
  toggleTheme: () => {},
});

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

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

  useEffect(() => {
    const rafId = window.requestAnimationFrame(() => {
      setMounted(true);
      const stored = localStorage.getItem('qr-theme') as Theme | null;
      if (stored) {
        setTheme(stored);
      } else if (window.matchMedia('(prefers-color-scheme: dark)').matches) {
        setTheme('dark');
      }
    });

    return () => window.cancelAnimationFrame(rafId);
  }, []);

  useEffect(() => {
    if (!mounted) return;
    document.documentElement.classList.toggle('dark', theme === 'dark');
    localStorage.setItem('qr-theme', theme);
  }, [theme, mounted]);

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

  if (!mounted) {
    return <div className="min-h-screen" />;
  }

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