function DataLayerWrapper() {
    this.gtag = window.gtag || function() { window.dataLayer.push(arguments); };
    // Kutsutaan session_start-metodia konstruktoriin
    this.sessionStart();
}

// Metodi: sessionStart
DataLayerWrapper.prototype.sessionStart = function() {
    const sessionStartData = {
        event: "session_start",
        currency: "EUR"
    };
    this.gtag('event', 'session_start', sessionStartData);
    console.log(sessionStartData);
};

// Metodi: viewItem
DataLayerWrapper.prototype.viewItem = function(itemDetails) {
    const viewItemData = {
        currency: "EUR",
        items: [itemDetails]
    };
    this.gtag('event', 'view_item', viewItemData);
    console.log(viewItemData);
};

// Metodi: selectItem
DataLayerWrapper.prototype.selectItem = function(itemDetails) {
    const selectItemData = {
        currency: "EUR",
        items: [itemDetails]
    };
    this.gtag('event', 'select_item', selectItemData);
    console.log(selectItemData);
};

// Metodi: addToCart
DataLayerWrapper.prototype.addToCart = function(itemDetails) {
    const addToCartData = {
        currency: "EUR",
        items: [itemDetails]
    };
    this.gtag('event', 'add_to_cart', addToCartData);
    console.log(addToCartData);
};

// Metodi: addShippingInfo
DataLayerWrapper.prototype.addShippingInfo = function(shippingDetails, itemDetails) {
    const addShippingInfoData = {
        currency: "EUR",
        value: shippingDetails.value,
        coupon: shippingDetails.coupon,
        shipping_tier: shippingDetails.shipping_tier,
        items: [itemDetails]
    };
    this.gtag('event', 'add_shipping_info', addShippingInfoData);
    console.log(addShippingInfoData);
};

// Metodi: purchase
DataLayerWrapper.prototype.purchase = function(purchaseDetails, itemDetails) {
    const purchaseData = {
        currency: "EUR",
        transaction_id: purchaseDetails.transaction_id,
        value: purchaseDetails.value,
        tax: purchaseDetails.tax,
        shipping: purchaseDetails.shipping,
        coupon: purchaseDetails.coupon,
        items: [itemDetails]
    };
    this.gtag('event', 'purchase', purchaseData);
    console.log(purchaseData);
};