'use client';

import { useEffect, useState } from 'react';

export default function ThemeToggle() {
  const [isDark, setIsDark] = useState(() => {
    if (typeof window !== 'undefined') {
      const stored = localStorage.getItem('theme');
      if (stored) {
        return stored === 'dark';
      }
      return window.matchMedia('(prefers-color-scheme: dark)').matches;
    }
    return false;
  });

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

  const toggleTheme = () => {
    setIsDark(!isDark);
  };

  return (
    <button
      onClick={toggleTheme}
      className="fixed top-4 right-4 p-2 rounded-lg bg-gray-200 dark:bg-gray-800 text-gray-800 dark:text-gray-200 hover:bg-gray-300 dark:hover:bg-gray-700 transition-colors"
      aria-label="Toggle theme"
    >
      {isDark ? (
        <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
          <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 3v1m0 16v1m9-9h-1M4 12H3m15.364 6.364l-.707-.707M6.343 6.343l-.707-.707m12.728 0l-.707.707M6.343 17.657l-.707.707M16 12a4 4 0 11-8 0 4 4 0 018 0z" />
        </svg>
      ) : (
        <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
          <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M20.354 15.354A9 9 0 018.646 3.646 9.003 9.003 0 0012 21a9.003 9.003 0 008.354-5.646z" />
        </svg>
      )}
    </button>
  );
}

