frontend/src/components/Navbar.jsx

import React from 'react';
import { Fragment } from 'react';
import { Link } from 'react-router-dom';
import { Disclosure, Menu, Transition } from '@headlessui/react';
import { Bars3Icon, XMarkIcon, UserCircleIcon } from '@heroicons/react/24/outline';

const navigation = [
  { name: '儀表板', href: '/', current: true },
  { name: '飲食追蹤', href: '/food', current: false },
  { name: 'AI食物分析', href: '/food-ai', current: false },
  { name: '飲水紀錄', href: '/water', current: false },
  { name: '運動紀錄', href: '/exercise', current: false },
];

function classNames(...classes) {
  return classes.filter(Boolean).join(' ');
}

export default function Navbar() {
  return (
    <Disclosure as="nav" className="bg-white shadow-lg">
      {({ open }) => (
        <>
          <div className="mx-auto max-w-7xl px-4 sm:px-6 lg:px-8">
            <div className="flex h-16 justify-between">
              <div className="flex">
                <div className="flex flex-shrink-0 items-center">
                  <span className="text-2xl font-bold text-indigo-600">健康助手</span>
                </div>
                <div className="hidden sm:ml-6 sm:flex sm:space-x-8">
                  {navigation.map((item) => (
                    <Link
                      key={item.name}
                      to={item.href}
                      className={classNames(
                        item.current
                          ? 'border-indigo-500 text-gray-900'
                          : 'border-transparent text-gray-500 hover:border-gray-300 hover:text-gray-700',
                        'inline-flex items-center border-b-2 px-1 pt-1 text-sm font-medium'
                      )}
                    >
                      {item.name}
                    </Link>
                  ))}
                </div>
              </div>
              
              <div className="hidden sm:ml-6 sm:flex sm:items-center">
                <Menu as="div" className="relative ml-3">
                  <div>
                    <Menu.Button className="flex rounded-full bg-white text-sm focus:outline-none focus:ring-2 focus:ring-indigo-500 focus:ring-offset-2">
                      <UserCircleIcon className="h-8 w-8 text-gray-400" aria-hidden="true" />
                    </Menu.Button>
                  </div>
                  <Transition
                    as={Fragment}
                    enter="transition ease-out duration-200"
                    enterFrom="transform opacity-0 scale-95"
                    enterTo="transform opacity-100 scale-100"
                    leave="transition ease-in duration-75"
                    leaveFrom="transform opacity-100 scale-100"
                    leaveTo="transform opacity-0 scale-95"
                  >
                    <Menu.Items className="absolute right-0 z-10 mt-2 w-48 origin-top-right rounded-md bg-white py-1 shadow-lg ring-1 ring-black ring-opacity-5 focus:outline-none">
                      <Menu.Item>
                        {({ active }) => (
                          <Link
                            to="/profile"
                            className={classNames(
                              active ? 'bg-gray-100' : '',
                              'block px-4 py-2 text-sm text-gray-700'
                            )}
                          >
                            個人資料
                          </Link>
                        )}
                      </Menu.Item>
                      <Menu.Item>
                        {({ active }) => (
                          <a
                            href="#"
                            className={classNames(
                              active ? 'bg-gray-100' : '',
                              'block px-4 py-2 text-sm text-gray-700'
                            )}
                          >
                            登出
                          </a>
                        )}
                      </Menu.Item>
                    </Menu.Items>
                  </Transition>
                </Menu>
              </div>

              <div className="-mr-2 flex items-center sm:hidden">
                <Disclosure.Button className="inline-flex items-center justify-center rounded-md p-2 text-gray-400 hover:bg-gray-100 hover:text-gray-500 focus:outline-none focus:ring-2 focus:ring-inset focus:ring-indigo-500">
                  {open ? (
                    <XMarkIcon className="block h-6 w-6" aria-hidden="true" />
                  ) : (
                    <Bars3Icon className="block h-6 w-6" aria-hidden="true" />
                  )}
                </Disclosure.Button>
              </div>
            </div>
          </div>

          <Disclosure.Panel className="sm:hidden">
            <div className="space-y-1 pb-3 pt-2">
              {navigation.map((item) => (
                <Link
                  key={item.name}
                  to={item.href}
                  className={classNames(
                    item.current
                      ? 'bg-indigo-50 border-indigo-500 text-indigo-700'
                      : 'border-transparent text-gray-500 hover:bg-gray-50 hover:border-gray-300 hover:text-gray-700',
                    'block border-l-4 py-2 pl-3 pr-4 text-base font-medium'
                  )}
                >
                  {item.name}
                </Link>
              ))}
            </div>
          </Disclosure.Panel>
        </>
      )}
    </Disclosure>
  );
}