GtmHelper = {};
GtmHelper.products = [];
GtmHelper.userData = null;

GtmHelper.addProduct = function(name, price, id, itemCategory, quantity = 1) {
    GtmHelper.products.push({
        name, price, id, itemCategory, quantity
    });
};

GtmHelper.addUserData = function(email, phone, name, surname, city, zip, country) {
    GtmHelper.userData = {
        email, phone, name, surname, city, zip, country
    };
};

GtmHelper.render = function(action = 'add_to_cart', transactionId = '', isNewCustomer = false, tax = 0) {
    const items = [];
    let totalPrice = 0;
    GtmHelper.products.forEach(function(product, i) {
        items.push({
            'item_id': product.id,
            'item_name': product.name,
            'price': parseFloat(product.price),
            'quantity': product.quantity,
            'index': i,
            'item_category': product.itemCategory
        });
        totalPrice = totalPrice + (parseFloat(product.price) * product.quantity);
    });

    const result = {
        'event': action,
        'ecommerce': {
            'currency': 'CZK',
            'value': parseFloat(totalPrice),
            'items': items
        }
    };

    if (action === 'pending_purchase' && GtmHelper.userData) {
        const user = GtmHelper.userData;
        result.user_data = {
            email_address : user.email,
            phone_number: user.phone,
            address: {
                first_name: user.name,
                last_name: user.surname,
                city: user.city,
                postal_code: user.zip,
                country: user.country
            }
        }

        result.transaction_id = transactionId;
        result.new_customer = isNewCustomer;
        result.tax = parseFloat(tax);
        result.shipping = 0.0;
    }

    return result;
}

GtmHelper.addWebhostingToCart = function(name, price, id) {
    dataLayer.push({ ecommerce: null });
    GtmHelper.addProduct(`Webhosting: ${name}`, price, id, 'Webhosting');
    const gtmEvent = GtmHelper.render();
    dataLayer.push(gtmEvent);
    console.log(dataLayer);
}

GtmHelper.addMailToCart = function(name, price, id) {
    dataLayer.push({ ecommerce: null });
    GtmHelper.addProduct(name, price, id, 'Mailhosting');
    const gtmEvent = GtmHelper.render();
    dataLayer.push(gtmEvent);
}