// --- 3. auth.js ---
function getDeviceId() { 
    let did = localStorage.getItem('xv_device_id'); 
    if (!did) { 
        did = 'dev_' + Math.random().toString(36).substring(2, 15) + Date.now().toString(36); 
        localStorage.setItem('xv_device_id', did); 
    } 
    return did; 
}

async function checkSession() {
    const { data: { session } } = await supabaseClient.auth.getSession();
    if (session) {
        currentUser = session.user;
        document.getElementById('form-login').classList.add('hidden');
        document.getElementById('form-vip').classList.remove('hidden');

        const { data } = await supabaseClient.from('profiles').select('*').eq('id', currentUser.id).single();
        const now = new Date();
        const expiryDate = data?.expiry_date ? new Date(data.expiry_date) : null;
        isVipActive = data?.is_vip && (!expiryDate || expiryDate > now);

        const userInfo = document.getElementById('user-info');
        if (isVipActive) {
            const expiryText = expiryDate ? `Hết hạn: ${expiryDate.toLocaleDateString('vi-VN')}` : "Vĩnh viễn";
            userInfo.innerHTML = `Tài khoản: <b>${currentUser.email}</b><br><span style="color:#22ff99;font-weight:700">✓ VIP ACTIVE</span><br><small>${expiryText}</small>`;
            document.getElementById('vip-floating-btn').style.background = "linear-gradient(135deg, #22ff99, #00cc77)";
        } else {
            userInfo.innerHTML = `Tài khoản: <b>${currentUser.email}</b><br><span style="color:#ff8a8a">Tài khoản thường</span>`;
            document.getElementById('vip-floating-btn').style.background = "linear-gradient(135deg, #6c757d, #495057)";
        }
    } else {
        document.getElementById('form-login').classList.remove('hidden');
        document.getElementById('form-vip').classList.add('hidden');
        currentUser = null; isVipActive = false;
    }
}

async function handleLogin() {
    const email = document.getElementById('u_email').value.trim();
    const password = document.getElementById('u_password').value.trim();
    const btn = document.getElementById('btn-login');
    btn.innerText = "Đang xử lý...";

    let { error } = await supabaseClient.auth.signInWithPassword({ email, password });
    if (error) { 
        const { error: signUpErr } = await supabaseClient.auth.signUp({ email, password }); 
        if (!signUpErr) saveCredentials(email, password); 
    } else { 
        saveCredentials(email, password); 
    }

    btn.innerText = "ĐĂNG NHẬP / ĐĂNG KÝ"; 
    checkSession();
}

function saveCredentials(email, pass) { 
    localStorage.setItem('xv_vip_email', email); 
    localStorage.setItem('xv_vip_pass', pass); 
}