feat: fill shippingInfo on setShippingMethod

package.json

@@ -32,6 +32,7 @@
 	"dependencies": {
 		"basic-auth": "^2.0.1",
 		"body-parser": "^1.20.2",
+		"decimal.js": "10.4.3",
 		"deep-equal": "^2.2.3",
 		"express": "^4.19.2",
 		"light-my-request": "^5.11.1",

src/product-projection-search.ts

@@ -61,7 +61,7 @@ export class ProductProjectionSearch {
 			.all(projectKey, "product")
 			.map((r) => this.transform(r, params.staged ?? false))
 			.filter((p) => {
-				if (!params.staged ?? false) {
+				if (!(params.staged ?? false)) {
 					return p.published;
 				}
 				return true;

src/product-search.ts

@@ -29,7 +29,7 @@ export class ProductSearch {
 				this.transform(r, params.productProjectionParameters?.staged ?? false),
 			)
 			.filter((p) => {
-				if (!params.productProjectionParameters?.staged ?? false) {
+				if (!(params.productProjectionParameters?.staged ?? false)) {
 					return p.published;
 				}
 				return true;

src/repositories/cart/actions.ts

@@ -2,6 +2,10 @@ import {
 	CartSetAnonymousIdAction,
 	CartSetCustomerIdAction,
 	CartUpdateAction,
+	CentPrecisionMoney,
+	InvalidOperationError,
+	MissingTaxRateForCountryError,
+	ShippingMethodDoesNotMatchCartError,
 	type Address,
 	type AddressDraft,
 	type Cart,
@@ -32,9 +36,15 @@ import {
 	type ProductPagedQueryResponse,
 	type ProductVariant,
 } from "@commercetools/platform-sdk";
-import { DirectDiscount } from "@commercetools/platform-sdk/dist/declarations/src/generated/models/cart";
+import {
+	DirectDiscount,
+	TaxPortion,
+	TaxedItemPrice,
+} from "@commercetools/platform-sdk/dist/declarations/src/generated/models/cart";
+import { Decimal } from "decimal.js/decimal";
 import { v4 as uuidv4 } from "uuid";
 import { CommercetoolsError } from "~src/exceptions";
+import { getShippingMethodsMatchingCart } from "~src/shipping";
 import type { Writable } from "~src/types";
 import {
 	AbstractUpdateHandler,
@@ -46,6 +56,7 @@ import {
 	createCentPrecisionMoney,
 	createCustomFields,
 	createTypedMoney,
+	roundDecimal,
 } from "../helpers";
 import {
 	calculateCartTotalPrice,
@@ -575,20 +586,162 @@ export class CartUpdateHandler
 		{ shippingMethod }: CartSetShippingMethodAction,
 	) {
 		if (shippingMethod) {
-			const method = this._storage.getByResourceIdentifier<"shipping-method">(
+			if (resource.taxMode === "External") {
+				throw new Error("External tax rate is not supported");
+			}
+
+			const country = resource.shippingAddress?.country;
+
+			if (!country) {
+				throw new CommercetoolsError<InvalidOperationError>({
+					code: "InvalidOperation",
+					message: `The cart with ID '${resource.id}' does not have a shipping address set.`,
+				});
+			}
+
+			// Bit of a hack: calling this checks that the resource identifier is
+			// valid (i.e. id xor key) and that the shipping method exists.
+			this._storage.getByResourceIdentifier<"shipping-method">(
 				context.projectKey,
 				shippingMethod,
 			);
 
-			// Based on the address we should select a shipping zone and
-			// use that to define the price.
+			// getShippingMethodsMatchingCart does the work of determining whether the
+			// shipping method is allowed for the cart, and which shipping rate to use
+			const shippingMethods = getShippingMethodsMatchingCart(
+				context,
+				this._storage,
+				resource,
+				{
+					expand: ["zoneRates[*].zone"],
+				},
+			);
+
+			const method = shippingMethods.results.find((candidate) =>
+				shippingMethod.id
+					? candidate.id === shippingMethod.id
+					: candidate.key === shippingMethod.key,
+			);
+
+			// Not finding the method in the results means it's not allowed, since
+			// getShippingMethodsMatchingCart only returns allowed methods and we
+			// already checked that the method exists.
+			if (!method) {
+				throw new CommercetoolsError<ShippingMethodDoesNotMatchCartError>({
+					code: "ShippingMethodDoesNotMatchCart",
+					message: `The shipping method with ${shippingMethod.id ? `ID '${shippingMethod.id}'` : `key '${shippingMethod.key}'`} is not allowed for the cart with ID '${resource.id}'.`,
+				});
+			}
+
+			const taxCategory = this._storage.getByResourceIdentifier<"tax-category">(
+				context.projectKey,
+				method.taxCategory,
+			);
+
+			// TODO: match state in addition to country
+			const taxRate = taxCategory.rates.find(
+				(rate) => rate.country === country,
+			);
+
+			if (!taxRate) {
+				throw new CommercetoolsError<MissingTaxRateForCountryError>({
+					code: "MissingTaxRateForCountry",
+					message: `Tax category '${taxCategory.id}' is missing a tax rate for country '${country}'.`,
+					taxCategoryId: taxCategory.id,
+				});
+			}
+
+			// TODO: are zones on a single shipping method mutually exclusive in terms of countries in the set? If not, need to determine what to do in case of multiple matches.
+			const zoneRate = method.zoneRates.find((rate) =>
+				rate.zone.obj!.locations.some((loc) => loc.country === country),
+			);
+
+			if (!zoneRate) {
+				// This shouldn't happen because getShippingMethodsMatchingCart already
+				// filtered out shipping methods without any zones matching the address
+				throw new Error("Zone rate not found");
+			}
+
+			// TODO: how to pick which shipping rate in array to use? All in array are
+			// matching, but could there be multiple matching rates for a single zone?
+			const shippingRate = zoneRate.shippingRates[0];
+			if (!shippingRate) {
+				// This shouldn't happen because getShippingMethodsMatchingCart already
+				// filtered out shipping methods without any matching rates
+				throw new Error("Shipping rate not found");
+			}
+
+			const shippingRateTier = shippingRate.tiers.find(
+				(tier) => tier.isMatching,
+			);
+			if (shippingRateTier && shippingRateTier.type !== "CartValue") {
+				throw new Error("Non-CartValue shipping rate tier is not supported");
+			}
+
+			const shippingPrice = shippingRateTier
+				? createCentPrecisionMoney(shippingRateTier.price)
+				: shippingRate.price;
+
+			// TODO: handle freeAbove
+
+			const totalGross: CentPrecisionMoney = taxRate.includedInPrice
+				? shippingPrice
+				: {
+						...shippingPrice,
+						centAmount: roundDecimal(
+							new Decimal(shippingPrice.centAmount).mul(1 + taxRate.amount),
+							resource.taxRoundingMode,
+						).toNumber(),
+					};
+
+			const totalNet: CentPrecisionMoney = taxRate.includedInPrice
+				? {
+						...shippingPrice,
+						centAmount: roundDecimal(
+							new Decimal(shippingPrice.centAmount).div(1 + taxRate.amount),
+							resource.taxRoundingMode,
+						).toNumber(),
+					}
+				: shippingPrice;
+
+			const taxPortions: TaxPortion[] = [
+				{
+					name: taxRate.name,
+					rate: taxRate.amount,
+					amount: {
+						...shippingPrice,
+						centAmount: totalGross.centAmount - totalNet.centAmount,
+					},
+				},
+			];
+
+			const totalTax: CentPrecisionMoney = {
+				...shippingPrice,
+				centAmount: taxPortions.reduce(
+					(acc, portion) => acc + portion.amount.centAmount,
+					0,
+				),
+			};
+
+			const taxedPrice: TaxedItemPrice = {
+				totalNet,
+				totalGross,
+				taxPortions,
+				totalTax,
+			};
+
 			// @ts-ignore
 			resource.shippingInfo = {
 				shippingMethod: {
 					typeId: "shipping-method",
 					id: method.id,
 				},
 				shippingMethodName: method.name,
+				price: shippingPrice,
+				shippingRate,
+				taxedPrice,
+				taxRate,
+				taxCategory: method.taxCategory,
 			};
 		} else {
 			resource.shippingInfo = undefined;

src/repositories/helpers.ts

@@ -3,6 +3,7 @@ import {
 	BusinessUnitKeyReference,
 	BusinessUnitReference,
 	BusinessUnitResourceIdentifier,
+	RoundingMode,
 	type Address,
 	type Associate,
 	type AssociateDraft,
@@ -29,6 +30,7 @@ import {
 	type Type,
 	type _Money,
 } from "@commercetools/platform-sdk";
+import { Decimal } from "decimal.js/decimal";
 import type { Request } from "express";
 import { v4 as uuidv4 } from "uuid";
 import { CommercetoolsError } from "~src/exceptions";
@@ -84,6 +86,25 @@ export const createPrice = (draft: PriceDraft): Price => ({
 	value: createTypedMoney(draft.value),
 });
 
+/**
+ * Rounds a decimal to the nearest whole number using the specified
+ * (Commercetools) rounding mode.
+ *
+ * @see https://docs.commercetools.com/api/projects/carts#roundingmode
+ */
+export const roundDecimal = (decimal: Decimal, roundingMode: RoundingMode) => {
+	switch (roundingMode) {
+		case "HalfEven":
+			return decimal.toDecimalPlaces(0, Decimal.ROUND_HALF_EVEN);
+		case "HalfUp":
+			return decimal.toDecimalPlaces(0, Decimal.ROUND_HALF_UP);
+		case "HalfDown":
+			return decimal.toDecimalPlaces(0, Decimal.ROUND_HALF_DOWN);
+		default:
+			throw new Error(`Unknown rounding mode: ${roundingMode}`);
+	}
+};
+
 export const createCentPrecisionMoney = (value: _Money): CentPrecisionMoney => {
 	// Taken from https://docs.adyen.com/development-resources/currency-codes
 	let fractionDigits = 2;

src/repositories/product-projection.ts

@@ -66,7 +66,7 @@ export class ProductProjectionRepository extends AbstractResourceRepository<"pro
 			.all(context.projectKey, "product")
 			.map((r) => this._searchService.transform(r, params.staged ?? false))
 			.filter((p) => {
-				if (!params.staged ?? false) {
+				if (!(params.staged ?? false)) {
 					return p.published;
 				}
 				return true;

src/repositories/shipping-method/index.ts

@@ -1,14 +1,12 @@
 import {
-	InvalidOperationError,
 	type ShippingMethod,
 	type ShippingMethodDraft,
 	type ZoneRate,
 	type ZoneRateDraft,
 	type ZoneReference,
 } from "@commercetools/platform-sdk";
-import { CommercetoolsError } from "~src/exceptions";
 import { getBaseResourceProperties } from "../../helpers";
-import { markMatchingShippingRate } from "../../shippingCalculator";
+import { getShippingMethodsMatchingCart } from "../../shipping";
 import { AbstractStorage } from "../../storage/abstract";
 import {
 	AbstractResourceRepository,
@@ -69,57 +67,7 @@ export class ShippingMethodRepository extends AbstractResourceRepository<"shippi
 			return undefined;
 		}
 
-		if (!cart.shippingAddress?.country) {
-			throw new CommercetoolsError<InvalidOperationError>({
-				code: "InvalidOperation",
-				message: `The cart with ID '${cart.id}' does not have a shipping address set.`,
-			});
-		}
-
-		// Get all shipping methods that have a zone that matches the shipping address
-		const zones = this._storage.query<"zone">(context.projectKey, "zone", {
-			where: [`locations(country="${cart.shippingAddress.country}"))`],
-			limit: 100,
-		});
-		const zoneIds = zones.results.map((zone) => zone.id);
-		const shippingMethods = this.query(context, {
-			"where": [
-				`zoneRates(zone(id in (:zoneIds)))`,
-				`zoneRates(shippingRates(price(currencyCode="${cart.totalPrice.currencyCode}")))`,
-			],
-			"var.zoneIds": zoneIds,
-			"expand": params.expand,
-		});
-
-		// Make sure that each shipping method has exactly one shipping rate and
-		// that the shipping rate is marked as matching
-		const results = shippingMethods.results
-			.map((shippingMethod) => {
-				// Iterate through the zoneRates, process the shipping rates and filter
-				// out all zoneRates which have no matching shipping rates left
-				const rates = shippingMethod.zoneRates
-					.map((zoneRate) => ({
-						zone: zoneRate.zone,
-
-						// Iterate through the shippingRates and mark the matching ones
-						// then we filter out the non-matching ones
-						shippingRates: zoneRate.shippingRates
-							.map((rate) => markMatchingShippingRate(cart, rate))
-							.filter((rate) => rate.isMatching),
-					}))
-					.filter((zoneRate) => zoneRate.shippingRates.length > 0);
-
-				return {
-					...shippingMethod,
-					zoneRates: rates,
-				};
-			})
-			.filter((shippingMethod) => shippingMethod.zoneRates.length > 0);
-
-		return {
-			...shippingMethods,
-			results: results,
-		};
+		return getShippingMethodsMatchingCart(context, this._storage, cart, params);
 	}
 
 	private _transformZoneRateDraft(