fix: stop double tax when prices are entered inclusive of tax

includes/Common.php

@@ -230,8 +230,11 @@ public function get_tax_location( $args, $order ) {
             $args['state']    = $order->get_shipping_state();
             $args['postcode'] = $order->get_shipping_postcode();
             $args['city']     = $order->get_shipping_city();
-        } else {
-            // Default to store base address for POS orders.
+        }
+
+        // Walk-in POS orders often carry no billing/shipping address; an empty
+        // country resolves no tax rates at all. Fall back to the store base.
+        if ( empty( $args['country'] ) ) {
             $args['country']  = \WC()->countries->get_base_country();
             $args['state']    = \WC()->countries->get_base_state();
             $args['postcode'] = \WC()->countries->get_base_postcode();

includes/REST/Manager.php

@@ -38,6 +38,7 @@ public function __construct() {
         add_filter( 'woocommerce_rest_prepare_product_cat', [ $this, 'category_response' ], 10, 3 );
         add_filter( 'woocommerce_rest_prepare_tax', [ $this, 'tax_response' ], 10, 3 );
         add_filter( 'woocommerce_rest_pre_insert_shop_order_object', [ $this, 'validate_item_stock_before_order' ], 10, 3 );
+        add_filter( 'woocommerce_rest_pre_insert_shop_order_object', [ $this, 'convert_inclusive_line_totals' ], 20, 3 );
     }
 
     /**
@@ -164,7 +165,13 @@ public function validate_item_stock_before_order( $order, $request, $creating )
         $items = $order->get_items();
 
         foreach ( $items as $item ) {
-            $product              = $item->get_product();
+            $product = $item->get_product();
+
+            // Custom/misc lines have no product and no stock to validate.
+            if ( ! $product ) {
+                continue;
+            }
+
             $is_manage_stock      = $product->get_manage_stock();
             $is_backorder_allowed = $product->get_backorders();
 
@@ -182,4 +189,95 @@ public function validate_item_stock_before_order( $order, $request, $creating )
 
         return $order;
     }
+
+    /**
+     * Net out bundled tax from POS line item totals when prices include tax.
+     *
+     * WC order line totals are always tax-exclusive, but the POS frontend
+     * posts line totals in entry mode — the raw (gross) product price when the
+     * store enters prices inclusive of tax. Without this conversion WC adds
+     * tax on top of the gross amount and the order is taxed twice.
+     *
+     * Only payloads that explicitly post line totals are converted: the legacy
+     * Vue frontend omits `total`/`subtotal`, letting WC derive the correct net
+     * price itself, and must not be netted a second time.
+     *
+     * @since WEPOS_LITE_SINCE
+     *
+     * @param \WC_Order        $order    The order being saved.
+     * @param \WP_REST_Request $request  Request data.
+     * @param bool             $creating True when creating, false when updating.
+     *
+     * @return \WC_Order
+     */
+    public function convert_inclusive_line_totals( $order, $request, $creating ) {
+        if ( empty( $request['line_items'] ) || ! wc_tax_enabled() || ! wc_prices_include_tax() ) {
+            return $order;
+        }
+
+        $is_pos_order = false;
+
+        foreach ( (array) ( $request['meta_data'] ?? [] ) as $meta ) {
+            $key   = is_array( $meta ) ? ( $meta['key'] ?? '' ) : ( $meta->key ?? '' );
+            $value = is_array( $meta ) ? ( $meta['value'] ?? '' ) : ( $meta->value ?? '' );
+
+            if ( '_wepos_is_pos_order' === $key && $value ) {
+                $is_pos_order = true;
+                break;
+            }
+        }
+
+        if ( ! $is_pos_order ) {
+            return $order;
+        }
+
+        // Gross totals are only posted explicitly; payloads without them (legacy
+        // Vue frontend) already carry WC-derived net totals.
+        $posts_gross_totals = false;
+        foreach ( (array) $request['line_items'] as $posted_item ) {
+            if ( is_array( $posted_item ) && isset( $posted_item['total'] ) ) {
+                $posts_gross_totals = true;
+                break;
+            }
+        }
+
+        if ( ! $posts_gross_totals ) {
+            return $order;
+        }
+
+        foreach ( $order->get_items() as $item ) {
+            $product   = $item->get_product();
+            $tax_class = $item->get_tax_class();
+
+            if ( $product ) {
+                if ( ! $product->is_taxable() ) {
+                    continue;
+                }
+            } else {
+                // Custom/misc line — tax config travels in _wepos_pos_data meta.
+                $pos_data = json_decode( (string) $item->get_meta( '_wepos_pos_data' ), true );
+
+                if ( ! is_array( $pos_data ) || 'taxable' !== ( $pos_data['tax_status'] ?? 'taxable' ) ) {
+                    continue;
+                }
+
+                $tax_class = $pos_data['tax_class'] ?? $tax_class;
+            }
+
+            // Prices entered inclusive of tax are defined against base rates.
+            $rates = \WC_Tax::get_base_tax_rates( $tax_class );
+
+            if ( empty( $rates ) ) {
+                continue;
+            }
+
+            $total_tax    = array_sum( \WC_Tax::calc_inclusive_tax( (float) $item->get_total(), $rates ) );
+            $subtotal_tax = array_sum( \WC_Tax::calc_inclusive_tax( (float) $item->get_subtotal(), $rates ) );
+
+            $item->set_total( (float) $item->get_total() - $total_tax );
+            $item->set_subtotal( (float) $item->get_subtotal() - $subtotal_tax );
+        }
+
+        return $order;
+    }
 }

src/frontend/components/Cart.tsx

@@ -38,7 +38,7 @@ import AddFeeModal from './AddFeeModal';
 import OrderMetaModal from './OrderMetaModal';
 import { Slot } from '@wordpress/components';
 import { PluginArea } from '@wordpress/plugins';
-import { formatPrice, toFiniteNumber } from '../utils/helpers';
+import { formatPrice, toFiniteNumber, cartItemDisplayPrices } from '../utils/helpers';
 import { CART_STORE_NAME } from '../store/cart';
 import { PRODUCTS_STORE_NAME } from '../store/products';
 import CustomerSearch, { CustomerSearchHandle } from '../components/CustomerSearch';
@@ -127,6 +127,8 @@ const Cart = forwardRef<CartHandle, CartProps>(({
     serverOrder,
     isServerOrderDirty,
     taxDisplayMode,
+    pricesIncludeTax,
+    availableTax,
   } = useSelect((select) => {
     const store = select(CART_STORE_NAME) as any;
     return {
@@ -148,6 +150,8 @@ const Cart = forwardRef<CartHandle, CartProps>(({
       serverOrder: store.getServerOrder(),
       isServerOrderDirty: store.isServerOrderDirty(),
       taxDisplayMode: store.getTaxDisplayMode(),
+      pricesIncludeTax: store.getPricesIncludeTax(),
+      availableTax: store.getAvailableTax(),
     };
   }, []);
 
@@ -250,6 +254,18 @@ const Cart = forwardRef<CartHandle, CartProps>(({
     tax_class: string;
     tax_status: 'taxable' | 'none';
   }) => {
+    // Cashier enters the price in the store's entry mode (gross when prices
+    // include tax). Derive the per-unit tax from the selected tax class so
+    // display/net conversion works like catalog products.
+    const rate = product.tax_status === 'taxable'
+      ? findTaxRate(availableTax || [], product.tax_class)
+      : 0;
+    const taxAmount = !rate
+      ? 0
+      : pricesIncludeTax
+        ? (product.price * rate) / (100 + rate)
+        : (product.price * rate) / 100;
+
     const cartItem: POSCartItem = {
       id: Date.now(),
       product_id: 0,
@@ -264,7 +280,9 @@ const Cart = forwardRef<CartHandle, CartProps>(({
       on_sale: false,
       type: 'simple',
       attribute: [],
-      tax_amount: 0,
+      tax_amount: taxAmount,
+      tax_class: product.tax_class,
+      tax_status: product.tax_status,
     };
     addToCart(cartItem);
   };
@@ -304,9 +322,13 @@ const Cart = forwardRef<CartHandle, CartProps>(({
   const cartFormatPrice = (price: number | string): string | number =>
     formatPrice(price, orderCurrencySymbol || '');
 
-  // Single source of truth: store value, synced from woocommerce_tax_display_cart by Home.tsx.
+  // Single source of truth: store values, synced from WC tax settings by Home.tsx.
   const isTaxInclusive = taxDisplayMode === 'incl';
 
+  // Line tax bundled in the displayed prices (inclusive mode) — shown as a
+  // WC-style "Including Tax X" note under the subtotal, never as a row.
+  const includedTaxTotal = isTaxInclusive ? totalLineTax : 0;
+
   // Count visible columns for colSpan
   const visibleColumnCount = cartSettings.columns.filter((c) => c.enabled).length || 1;
 
@@ -399,12 +421,20 @@ const Cart = forwardRef<CartHandle, CartProps>(({
                 <tbody>
                   {cartItems.length > 0 ? (
                     cartItems.map((item: POSCartItem, index: number) => {
-                      const itemTotal = item.quantity * (item.on_sale ? item.sale_price : item.regular_price);
-                      const itemSubtotal = item.quantity * item.regular_price;
+                      // Mode-aware display prices — stored prices go stale when tax display settings change.
+                      const displayPrice = cartItemDisplayPrices(
+                        item,
+                        isTaxInclusive ? 'incl' : 'excl',
+                        pricesIncludeTax,
+                      );
+                      const itemTotal = item.quantity * displayPrice.unit;
+                      const itemSubtotal = item.quantity * displayPrice.regular;
 
                       // Server tax when available; otherwise client-computed from product tax_amount so the breakdown shows pre-save.
+                      // Line-id match first — custom lines all share product_id 0.
                       const serverLineItem = serverOrder && !isServerOrderDirty
-                        ? serverOrder.line_items?.find(
+                        ? serverOrder.line_items?.find((li: any) => li.id === item.id)
+                          || serverOrder.line_items?.find(
                             (li: any) => li.product_id === item.product_id && li.variation_id === (item.variation_id || 0)
                           )
                         : null;
@@ -558,22 +588,22 @@ const Cart = forwardRef<CartHandle, CartProps>(({
                                 {item.on_sale && isSubOptionEnabled('price', 'on_sale') ? (
                                   <div className="flex flex-col">
                                     <span className="text-xs text-muted-foreground line-through">
-                                      {cartFormatPrice(item.regular_price)}
+                                      {cartFormatPrice(displayPrice.regular)}
                                     </span>
                                     <span className="font-medium text-destructive">
-                                      {cartFormatPrice(item.sale_price)}
+                                      {cartFormatPrice(displayPrice.sale)}
                                     </span>
                                   </div>
                                 ) : (
-                                  <span>{cartFormatPrice(item.regular_price)}</span>
+                                  <span>{cartFormatPrice(displayPrice.regular)}</span>
                                 )}
                               </td>
                             )}
 
                             {/* REGULAR PRICE Column */}
                             {isColumnEnabled('regular_price') && (
                               <td className="p-3 text-sm text-muted-foreground">
-                                {cartFormatPrice(item.regular_price)}
+                                {cartFormatPrice(displayPrice.regular)}
                               </td>
                             )}
 
@@ -657,9 +687,9 @@ const Cart = forwardRef<CartHandle, CartProps>(({
               <div className="flex items-center justify-between border-b border-border p-[9px_12px]">
                 <div className="flex-1 text-sm">
                   {__('Subtotal', 'wepos')}
-                  {isTaxInclusive && totalLineTax > 0 && (
+                  {isTaxInclusive && includedTaxTotal > 0 && (
                     <span className="block text-xs font-normal text-muted-foreground">
-                      {__('Including Tax', 'wepos')}
+                      {__('Including Tax', 'wepos')} {cartFormatPrice(includedTaxTotal)}
                     </span>
                   )}
                 </div>
@@ -768,8 +798,9 @@ const Cart = forwardRef<CartHandle, CartProps>(({
                 </div>
               ))}
 
-              {/* Tax Lines (from server, only when not stale) */}
-              {serverOrder && !isServerOrderDirty && serverOrder.tax_lines.length > 0 && (
+              {/* Tax Lines (from server, only when not stale). Inclusive display: tax is
+                  part of the prices, so no separate rows — WC-style note instead below. */}
+              {!isTaxInclusive && serverOrder && !isServerOrderDirty && serverOrder.tax_lines.length > 0 && (
                 <>
                   {serverOrder.tax_lines.map((taxLine: any) => (
                     <div
@@ -793,7 +824,8 @@ const Cart = forwardRef<CartHandle, CartProps>(({
                 </>
               )}
 
-              {/* Total Tax (fallback when no detailed tax lines) */}
+              {/* Total Tax (fallback when no detailed tax lines). In inclusive display
+                  this only carries additive fee tax. */}
               {totalTax > 0 && (!serverOrder || isServerOrderDirty || serverOrder.tax_lines.length === 0) && (
                 <div className="flex items-center justify-between border-b border-border p-[9px_12px]">
                   <div className="flex-1 text-sm font-medium text-foreground">

src/frontend/components/PaymentModal.tsx

@@ -3,7 +3,7 @@ import { __ } from '@wordpress/i18n';
 import { useSelect } from '@wordpress/data';
 import { LoaderCircle, ArrowLeft, CreditCard } from 'lucide-react';
 import { POSGateway, POSCartItem, POSDiscountLine, POSFeeLine, POSShippingLine } from '../types';
-import { formatPrice } from '../utils/helpers';
+import { cartItemDisplayPrices, formatPrice } from '../utils/helpers';
 import { CART_STORE_NAME } from '../store/cart';
 import { PRODUCTS_STORE_NAME } from '../store/products';
 import { applyFilters } from '../hooks/useExtensions';
@@ -49,7 +49,7 @@ const PaymentModal: React.FC<PaymentModalProps> = ({
   cashAmountRef,
 }) => {
   // Get cart data from cart store
-  const { cartItems, subtotal, total, discountLines, feeLines, shippingLines, totalTax, orderCurrencySymbol } =
+  const { cartItems, subtotal, total, discountLines, feeLines, shippingLines, totalTax, totalLineTax, taxDisplayMode, pricesIncludeTax, orderCurrencySymbol } =
     useSelect((select) => {
       const store = select(CART_STORE_NAME) as any;
       return {
@@ -60,10 +60,18 @@ const PaymentModal: React.FC<PaymentModalProps> = ({
         feeLines: store.getFeeLines(),
         shippingLines: store.getShippingLines(),
         totalTax: store.getTotalTax(),
+        totalLineTax: store.getTotalLineTax(),
+        taxDisplayMode: store.getTaxDisplayMode(),
+        pricesIncludeTax: store.getPricesIncludeTax(),
         orderCurrencySymbol: store.getOrderCurrencySymbol(),
       };
     }, []);
 
+  // Inclusive display: line tax is part of the subtotal/total, not added on
+  // top — shown as a WC-style "(Including Tax X)" note, never as a row.
+  const isTaxInclusive = taxDisplayMode === 'incl';
+  const includedTax = isTaxInclusive ? totalLineTax : 0;
+
   // Get gateways from products store
   const { availableGateways } = useSelect((select) => {
     const store = select(PRODUCTS_STORE_NAME) as any;
@@ -126,9 +134,9 @@ const PaymentModal: React.FC<PaymentModalProps> = ({
     return parseFloat(fee.value);
   };
 
-  // Get item price
+  // Mode-aware display price — matches the cart rows and getSubtotal.
   const getItemPrice = (item: POSCartItem): number => {
-    return item.on_sale ? item.sale_price : item.regular_price;
+    return cartItemDisplayPrices(item, taxDisplayMode, pricesIncludeTax).unit;
   };
 
   if (!show) return null;
@@ -257,8 +265,8 @@ const PaymentModal: React.FC<PaymentModalProps> = ({
               </div>
             ))}
 
-            {/* Tax */}
-            {totalTax > 0 && (
+            {/* Tax — additive row only when prices exclude tax (WC cart behavior) */}
+            {!isTaxInclusive && totalTax > 0 && (
               <div className="flex justify-between py-1">
                 <span className="text-sm text-muted-foreground">
                   {__('Tax', 'wepos')}
@@ -280,6 +288,12 @@ const PaymentModal: React.FC<PaymentModalProps> = ({
                 {paymentFormatPrice(total)}
               </span>
             </div>
+            {/* WC-style note: "(includes Tax X)" under the total in inclusive display */}
+            {includedTax > 0 && (
+              <div className="flex justify-end pb-1 text-xs text-muted-foreground">
+                ({__('Including Tax', 'wepos')} {paymentFormatPrice(includedTax)})
+              </div>
+            )}
           </div>
         </div>