refactor calculation code

- implement fee
- centralize the code

src/features/order/orderSlice.ts

@@ -1,6 +1,7 @@
 import { createSlice, PayloadAction } from "@reduxjs/toolkit";
+import { OrderType } from "pages/checkout/hooks/types";
 import { RootState } from "redux/store";
-import { CartItem } from "utils/types/appTypes";
+import { CartItem, RestaurantDetails, Tax } from "utils/types/appTypes";
 
 interface LocationData {
   lat: number;
@@ -35,8 +36,9 @@ export interface GiftDetailsType {
 }
 
 interface CartState {
+  restaurant: Partial<RestaurantDetails>;
   items: CartItem[];
-  tmp: any;
+  tmp: unknown;
   specialRequest: string;
   location: LocationData | null;
   roomDetails: RoomDetailsType | null;
@@ -76,6 +78,7 @@ export const CART_STORAGE_KEYS = {
   ORDER_TYPE: "fascano_order_type",
   USE_LOYALTY_POINTS: "fascano_use_loyalty_points",
   LOYALTY_VALIDATION_ERROR: "fascano_loyalty_validation_error",
+  RESTAURANT: "fascano_restaurant",
 } as const;
 
 // Utility functions for localStorage
@@ -133,6 +136,7 @@ const initialState: CartState = {
     CART_STORAGE_KEYS.LOYALTY_VALIDATION_ERROR,
     null,
   ),
+  restaurant: getFromLocalStorage(CART_STORAGE_KEYS.RESTAURANT, { taxes: [] }),
 };
 
 const orderSlice = createSlice({
@@ -142,6 +146,15 @@ const orderSlice = createSlice({
     reset() {
       return initialState;
     },
+    updateRestaurant(state, action: PayloadAction<Partial<RestaurantDetails>>) {
+      state.restaurant = action.payload;
+      if (typeof window !== "undefined") {
+        localStorage.setItem(
+          CART_STORAGE_KEYS.RESTAURANT,
+          JSON.stringify(state.restaurant),
+        );
+      }
+    },
     addItem(
       state,
       action: PayloadAction<{
@@ -520,8 +533,21 @@ export const {
   validateLoyaltyPoints,
   clearLoyaltyValidationError,
   reset,
+  updateRestaurant,
 } = orderSlice.actions;
 
+// Tax calculation helper functions
+const calculateTaxAmount = (amount: number, tax: Tax): number => {
+  const percentage = parseFloat(tax.percentage);
+  return (percentage * amount) / 100;
+};
+
+const calculateTotalTax = (subtotal: number, taxes: Tax[]): number => {
+  return taxes
+    .filter((tax) => tax.is_active === 1)
+    .reduce((total, tax) => total + calculateTaxAmount(subtotal, tax), 0);
+};
+
 // Selectors
 export const selectCart = (state: RootState) => state.order;
 export const selectCartItems = (state: RootState) => state.order.items;
@@ -549,18 +575,6 @@ export const selectHighestPricedLoyaltyItem = (state: RootState) => {
   );
 };
 
-export const selectCartTotalWithLoyaltyDiscount = (state: RootState) => {
-  const total = selectCartTotal(state);
-  const useLoyaltyPoints = state.order.useLoyaltyPoints;
-  const highestLoyaltyItem = selectHighestPricedLoyaltyItem(state);
-
-  if (useLoyaltyPoints && highestLoyaltyItem) {
-    return total - highestLoyaltyItem.price;
-  }
-
-  return total;
-};
-
 export const selectLoyaltyValidation = (state: RootState) => {
   const useLoyaltyPoints = state.order.useLoyaltyPoints;
   const loyaltyItems = selectLoyaltyItems(state);
@@ -576,4 +590,25 @@ export const selectLoyaltyValidation = (state: RootState) => {
   };
 };
 
+// Tax selectors
+export const selectTaxes = (state: RootState) => state.order.restaurant.taxes;
+
+export const selectTaxAmount = (state: RootState) => {
+  const subtotal = selectCartTotal(state);
+  const taxes = selectTaxes(state);
+  return calculateTotalTax(subtotal, taxes || []);
+};
+
+export const selectGrandTotal = (state: RootState) => {
+  const loyaltyDiscount = selectHighestPricedLoyaltyItem(state)?.price || 0;
+  const taxAmount = selectTaxAmount(state);
+  const subtotal = selectCartTotal(state);
+  const deliveryFee =
+    state.order.orderType != OrderType.DineIn
+      ? Number(state.order.restaurant?.delivery_fees) || 0
+      : 0;
+
+  return subtotal + taxAmount - loyaltyDiscount + deliveryFee;
+};
+
 export default orderSlice.reducer;