figlet-ui/components/layout/ThemeToggle.tsx

'use client';

import * as React from 'react';
import { Moon, Sun } from 'lucide-react';
import { Button } from '@/components/ui/Button';

export function ThemeToggle() {
  const [theme, setTheme] = React.useState<'light' | 'dark'>('light');

  const toggleTheme = React.useCallback(() => {
    const newTheme = theme === 'light' ? 'dark' : 'light';
    setTheme(newTheme);
    localStorage.setItem('theme', newTheme);
    document.documentElement.classList.toggle('dark', newTheme === 'dark');
  }, [theme]);

  React.useEffect(() => {
    // Check for saved theme preference or default to light
    const savedTheme = localStorage.getItem('theme') as 'light' | 'dark' | null;
    const prefersDark = window.matchMedia('(prefers-color-scheme: dark)').matches;
    const initialTheme = savedTheme || (prefersDark ? 'dark' : 'light');

    setTheme(initialTheme);
    document.documentElement.classList.toggle('dark', initialTheme === 'dark');
  }, []);

  // Keyboard shortcut: Ctrl/Cmd + D
  React.useEffect(() => {
    const handleKeyDown = (e: KeyboardEvent) => {
      if (e.key === 'd' && (e.ctrlKey || e.metaKey)) {
        e.preventDefault();
        toggleTheme();
      }
    };

    window.addEventListener('keydown', handleKeyDown);
    return () => window.removeEventListener('keydown', handleKeyDown);
  }, [toggleTheme]);

  return (
    <Button
      variant="outline"
      size="icon"
      onClick={toggleTheme}
      aria-label="Toggle theme"
      title={`Switch to ${theme === 'light' ? 'dark' : 'light'} mode`}
    >
      {theme === 'light' ? (
        <Moon className="h-4 w-4" />
      ) : (
        <Sun className="h-4 w-4" />
      )}
    </Button>
  );
}