calculate delivery fee based on distance

src/modules/cart/providers/cart.service.ts

@@ -15,7 +15,7 @@ import { UserAddress } from '../../users/entities/user-address.entity';
 import { User } from '../../users/entities/user.entity';
 import { PaymentMethod } from '../../payments/entities/payment-method.entity';
 import { Delivery } from '../../delivery/entities/delivery.entity';
-import { DeliveryMethodEnum } from '../../delivery/interface/delivery';
+import { DeliveryMethodEnum, DeliveryFeeTypeEnum } from '../../delivery/interface/delivery';
 import { Cart, CartItem } from '../interfaces/cart.interface';
 import { CouponService } from 'src/modules/coupons/providers/coupon.service';
 import { OrderCouponDetail, OrderStatus } from 'src/modules/orders/interface/order.interface';
@@ -24,7 +24,7 @@ import { UserWallet } from 'src/modules/users/entities/user-wallet.entity';
 import { PaymentMethodEnum } from 'src/modules/payments/interface/payment';
 import { SetAllCartParmsDto } from '../dto/set-all-cart-params.dto';
 import { Order } from 'src/modules/orders/entities/order.entity';
-  
+
 @Injectable()
 export class CartService {
   private readonly CART_TTL = 3600; // 1 hour in seconds
@@ -489,7 +489,7 @@ export class CartService {
     cart.totalDiscount = couponDiscount + itemsDiscount;
 
     cart.tax = await this.calculateTax(cart.restaurantId, Math.max(0, subTotal - cart.totalDiscount));
-    cart.deliveryFee = await this.calculateDeliveryFee(cart.deliveryMethodId);
+    cart.deliveryFee = await this.calculateDeliveryFee(cart);
 
     // total = subtotal – totalDiscount + tax + deliveryFee
     cart.total = Math.max(0, subTotal - cart.totalDiscount) + cart.tax + cart.deliveryFee;
@@ -988,10 +988,73 @@ export class CartService {
     return (Math.max(0, amountAfterDiscounts) * vat) / 100;
   }
 
-  private async calculateDeliveryFee(deliveryMethodId?: string): Promise<number> {
+  private async calculateDeliveryFee(cart: Cart): Promise<number> {
+    const deliveryMethodId = cart.deliveryMethodId;
     if (!deliveryMethodId) return 0;
-    const deliveryMethod = await this.em.findOne(Delivery, { id: deliveryMethodId });
+
+    const deliveryMethod = await this.em.findOne(Delivery, { id: deliveryMethodId }, { populate: ['restaurant'] });
     if (!deliveryMethod || !deliveryMethod.enabled) return 0;
-    return Number(deliveryMethod.deliveryFee) || 0;
+
+    // If not distance based, return fixed delivery fee
+    if (deliveryMethod.deliveryFeeType !== DeliveryFeeTypeEnum.DISTANCE_BASED) {
+      return Number(deliveryMethod.deliveryFee) || 0;
+    }
+
+    // For distance based calculation we need restaurant and user coordinates
+    const restaurant = (deliveryMethod as any).restaurant as Restaurant | undefined;
+    const userAddr = cart.userAddress;
+
+    if (!restaurant || restaurant.latitude == null || restaurant.longitude == null) {
+      // fallback to configured fixed fee when coordinates are missing
+      return Number(deliveryMethod.deliveryFee) || 0;
+    }
+
+    if (!userAddr || userAddr.latitude == null || userAddr.longitude == null) {
+      return Number(deliveryMethod.deliveryFee) || 0;
+    }
+
+    const restLat = Number(restaurant.latitude);
+    const restLng = Number(restaurant.longitude);
+    const userLat = Number(userAddr.latitude);
+    const userLng = Number(userAddr.longitude);
+
+    const distanceKm = this.getDistanceKmRounded(restLat, restLng, userLat, userLng);
+
+    // Try to read either possible property names (legacy vs new)
+    const perKm = Number(deliveryMethod.perKilometerFee);
+    const minFee = Number(deliveryMethod.distanceBasedMinCost);
+
+    let fee = 0;
+    if (perKm <= 0) {
+      fee = Number(deliveryMethod.deliveryFee) || 0;
+    } else {
+      fee = distanceKm * perKm;
+    }
+
+    if (minFee > 0 && fee < minFee) fee = minFee;
+
+    return Math.max(0, Number(fee));
+  }
+
+  private toRad(value: number): number {
+    return (value * Math.PI) / 180;
+  }
+
+  private getDistanceKm(lat1: number, lng1: number, lat2: number, lng2: number): number {
+    const R = 6371; // Earth radius in KM
+
+    const dLat = this.toRad(lat2 - lat1);
+    const dLng = this.toRad(lng2 - lng1);
+
+    const a =
+      Math.sin(dLat / 2) ** 2 + Math.cos(this.toRad(lat1)) * Math.cos(this.toRad(lat2)) * Math.sin(dLng / 2) ** 2;
+
+    const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
+
+    return R * c;
+  }
+  private getDistanceKmRounded(lat1: number, lng1: number, lat2: number, lng2: number, precision = 2): number {
+    const distance = this.getDistanceKm(lat1, lng1, lat2, lng2);
+    return Number(distance.toFixed(precision));
   }
 }