public function add_to_cart( $product_id = 0, $quantity = 1, $variation_id = 0, $variation = array(), $cart_item_data = array() ) {
		try {
			$product_id   = absint( $product_id );
			$variation_id = absint( $variation_id );

			// Ensure we don't add a variation to the cart directly by variation ID.
			if ( 'product_variation' === get_post_type( $product_id ) ) {
				$variation_id = $product_id;
				$product_id   = wp_get_post_parent_id( $variation_id );
			}

			$product_data = wc_get_product( $variation_id ? $variation_id : $product_id );
			$quantity     = apply_filters( 'woocommerce_add_to_cart_quantity', $quantity, $product_id );

			if ( $quantity <= 0 || ! $product_data || 'trash' === $product_data->get_status() ) {
				return false;
			}

			// Load cart item data - may be added by other plugins.
			$cart_item_data = (array) apply_filters( 'woocommerce_add_cart_item_data', $cart_item_data, $product_id, $variation_id, $quantity );

			// Generate a ID based on product ID, variation ID, variation data, and other cart item data.
			$cart_id = $this->generate_cart_id( $product_id, $variation_id, $variation, $cart_item_data );

			// Find the cart item key in the existing cart.
			$cart_item_key = $this->find_product_in_cart( $cart_id );

			// Force quantity to 1 if sold individually and check for existing item in cart.
			if ( $product_data->is_sold_individually() ) {
				$quantity      = apply_filters( 'woocommerce_add_to_cart_sold_individually_quantity', 1, $quantity, $product_id, $variation_id, $cart_item_data );
				$found_in_cart = apply_filters( 'woocommerce_add_to_cart_sold_individually_found_in_cart', $cart_item_key && $this->cart_contents[ $cart_item_key ]['quantity'] > 0, $product_id, $variation_id, $cart_item_data, $cart_id );

				if ( $found_in_cart ) {
					/* translators: %s: product name */
					throw new Exception( sprintf( '<a href="%s" class="button wc-forward">%s</a> %s', wc_get_cart_url(), __( 'View cart', 'woocommerce' ), sprintf( __( 'You cannot add another "%s" to your cart.', 'woocommerce' ), $product_data->get_name() ) ) );
				}
			}

			if ( ! $product_data->is_purchasable() ) {
				$message = __( 'Sorry, this product cannot be purchased.', 'woocommerce' );
				/**
				 * Filters message about product unable to be purchased.
				 *
				 * @since 3.8.0
				 * @param string     $message Message.
				 * @param WC_Product $product_data Product data.
				 */
				$message = apply_filters( 'woocommerce_cart_product_cannot_be_purchased_message', $message, $product_data );
				throw new Exception( $message );
			}

			// Stock check - only check if we're managing stock and backorders are not allowed.
			if ( ! $product_data->is_in_stock() ) {
				/* translators: %s: product name */
				throw new Exception( sprintf( __( 'You cannot add &quot;%s&quot; to the cart because the product is out of stock.', 'woocommerce' ), $product_data->get_name() ) );
			}

			if ( ! $product_data->has_enough_stock( $quantity ) ) {
				/* translators: 1: product name 2: quantity in stock */
				throw new Exception( sprintf( __( 'You cannot add that amount of &quot;%1$s&quot; to the cart because there is not enough stock (%2$s remaining).', 'woocommerce' ), $product_data->get_name(), wc_format_stock_quantity_for_display( $product_data->get_stock_quantity(), $product_data ) ) );
			}

			// Stock check - this time accounting for whats already in-cart.
			if ( $product_data->managing_stock() ) {
				$products_qty_in_cart = $this->get_cart_item_quantities();

				if ( isset( $products_qty_in_cart[ $product_data->get_stock_managed_by_id() ] ) && ! $product_data->has_enough_stock( $products_qty_in_cart[ $product_data->get_stock_managed_by_id() ] + $quantity ) ) {
					throw new Exception(
						sprintf(
							'<a href="%s" class="button wc-forward">%s</a> %s',
							wc_get_cart_url(),
							__( 'View cart', 'woocommerce' ),
							/* translators: 1: quantity in stock 2: current quantity */
							sprintf( __( 'You cannot add that amount to the cart &mdash; we have %1$s in stock and you already have %2$s in your cart.', 'woocommerce' ), wc_format_stock_quantity_for_display( $product_data->get_stock_quantity(), $product_data ), wc_format_stock_quantity_for_display( $products_qty_in_cart[ $product_data->get_stock_managed_by_id() ], $product_data ) )
						)
					);
				}
			}

			// If cart_item_key is set, the item is already in the cart.
			if ( $cart_item_key ) {
				$new_quantity = $quantity + $this->cart_contents[ $cart_item_key ]['quantity'];
				$this->set_quantity( $cart_item_key, $new_quantity, false );
			} else {
				$cart_item_key = $cart_id;

				// Add item after merging with $cart_item_data - hook to allow plugins to modify cart item.
				$this->cart_contents[ $cart_item_key ] = apply_filters(
					'woocommerce_add_cart_item',
					array_merge(
						$cart_item_data,
						array(
							'key'          => $cart_item_key,
							'product_id'   => $product_id,
							'variation_id' => $variation_id,
							'variation'    => $variation,
							'quantity'     => $quantity,
							'data'         => $product_data,
							'data_hash'    => wc_get_cart_item_data_hash( $product_data ),
						)
					),
					$cart_item_key
				);
			}

			$this->cart_contents = apply_filters( 'woocommerce_cart_contents_changed', $this->cart_contents );

			do_action( 'woocommerce_add_to_cart', $cart_item_key, $product_id, $quantity, $variation_id, $variation, $cart_item_data );

			return $cart_item_key;

		} catch ( Exception $e ) {
			if ( $e->getMessage() ) {
				wc_add_notice( $e->getMessage(), 'error' );
			}
			return false;
		}
	}