function updateNavVisibility() {
    const token = localStorage.getItem('token');
    document.querySelectorAll('.anonymous-links, .user-links').forEach(el => {
        el.style.display = token ? 'none' : 'block';
    });
    document.querySelector('.user-links').style.display = token ? 'block' : 'none';
}

document.getElementById('logoutLink')?.addEventListener('click', (e) => {
    e.preventDefault();
    localStorage.removeItem('token');
    localStorage.removeItem('imie');
    window.location.href = '/';
});

document.addEventListener('DOMContentLoaded', () => {
    updateNavVisibility();
    
    // Aktualizuj awatar/imię w nagłówku
    const userName = localStorage.getItem('imie');
    if(userName) {
        const profileLink = document.querySelector('a[href="/profile.html"]');
        if(profileLink) profileLink.innerHTML = `👤 ${userName}`;
    }
});

async function loadUserData() {
    const response = await fetch('/api/check-auth');
    const data = await response.json();
    updateNavVisibility(data.authenticated);
}

document.getElementById('loginForm')?.addEventListener('submit', async (e) => {
    e.preventDefault();
    const email = document.getElementById('loginEmail').value;
    const password = document.getElementById('loginPassword').value;

    const response = await fetch('/login', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
        },
        body: JSON.stringify({ email, haslo: password }),
    });

    const data = await response.json();
    if (response.ok) {
        localStorage.setItem('token', data.token);
        localStorage.setItem('imie', data.imie);
        window.location.href = '/';
    } else {
        alert(data.message || 'Logowanie nieudane');
    }
});

document.getElementById('registerForm')?.addEventListener('submit', async (e) => {
    e.preventDefault();
    const name = document.getElementById('registerName').value;
    const email = document.getElementById('registerEmail').value;
    const password = document.getElementById('registerPassword').value;
    const confirmPassword = document.getElementById('registerConfirmPassword').value;

    if (password !== confirmPassword) {
        alert('Hasła nie są identyczne');
        return;
    }

    const response = await fetch('/rejestracja', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
        },
        body: JSON.stringify({ imie: name, email, haslo: password, confirmPassword }),
    });

    if (response.ok) {
        alert('Rejestracja udana');
        window.location.href = '/login.html';
    } else {
        const data = await response.text();
        alert(data || 'Rejestracja nieudana');
    }
});

async function loadBooks() {
    try {
        const response = await fetch('/api/ksiazki');
        if (!response.ok) {
            throw new Error('Network response was not ok');
        }
        const books = await response.json();
        const booksContainer = document.getElementById('books-container');
        booksContainer.innerHTML = '';

        books.forEach(book => {
            const bookElement = document.createElement('div');
            bookElement.className = 'col-md-4';
            bookElement.innerHTML = `
                <div class="card mb-4">
                    <img src="${book.obraz_url || 'https://via.placeholder.com/150'}" class="card-img-top" alt="${book.tytul}">
                    <div class="card-body">
                        <h5 class="card-title">${book.tytul}</h5>
                        <p class="card-text">${book.autor}</p>
                        <p class="card-text">${book.cena} PLN</p>
                        <button class="btn btn-primary">Dodaj do koszyka</button>
                    </div>
                </div>
            `;
            booksContainer.appendChild(bookElement);
        });
    } catch (error) {
        console.error('Error loading books:', error);
        const booksContainer = document.getElementById('books-container');
        booksContainer.innerHTML = '<div class="col-12 text-center"><p>Wystąpił błąd podczas ładowania książek.</p></div>';
    }
}

document.addEventListener('DOMContentLoaded', () => {
    if (document.getElementById('books-container')) {
        loadBooks();
    }
});

document.addEventListener('DOMContentLoaded', () => {
    if (document.getElementById('books-container')) {
        loadBooks();
    }
});

document.addEventListener('DOMContentLoaded', () => {
    if (document.getElementById('books-container')) {
        loadBooks();
    }
});