Added the CalculateTaxes listener to cart update and shipping addre…

…ss change events

Changelog.md

@@ -43,6 +43,7 @@
 - Added the `Taxable` implementation to Foundation's CartItem, Product and MasterProductVariant classes
 - Added the extendable `TaxEngine` (facade) that can resolve tax rates from taxables, billing/shipping addresses (a place for various country-specific taxation drivers)
 - Added the `Merchant` interface
+- Added the `CalculateTaxes` listener to cart update and shipping address change events
 - BC: Added the `?CheckoutSubject` return type to the `getCart()` method of the `Checkout` interface
 - BC: Changed `Checkout::getShippingAddress()` return type to be nullable
 - BC: Added the void return type to `Checkout::setShippingAddress()`

src/Foundation/Listeners/CalculateTaxes.php

@@ -0,0 +1,73 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Contains the CalculateTaxes class.
+ *
+ * @copyright   Copyright (c) 2024 Vanilo UG
+ * @author      Attila Fulop
+ * @license     MIT
+ * @since       2024-01-30
+ *
+ */
+
+namespace Vanilo\Foundation\Listeners;
+
+use Illuminate\Support\Arr;
+use Vanilo\Adjustments\Contracts\Adjustable;
+use Vanilo\Adjustments\Contracts\Adjustment;
+use Vanilo\Adjustments\Models\AdjustmentTypeProxy;
+use Vanilo\Cart\Contracts\CartEvent;
+use Vanilo\Checkout\Contracts\CheckoutEvent;
+use Vanilo\Checkout\Facades\Checkout;
+use Vanilo\Foundation\Models\CartItem;
+use Vanilo\Support\Dto\DetailedAmount;
+use Vanilo\Taxes\Contracts\TaxRateResolver;
+
+class CalculateTaxes
+{
+    public function __construct(
+        protected ?TaxRateResolver $rateResolver,
+    ) {
+    }
+
+    public function handle(CheckoutEvent|CartEvent $event): void
+    {
+        if ($event instanceof CheckoutEvent) {
+            $checkout = $event->getCheckout();
+            $cart = $checkout->getCart();
+        } else {
+            $cart = $event->getCart();
+            Checkout::setCart($cart);
+            $checkout = Checkout::getFacadeRoot();
+        }
+
+        if (!$cart instanceof Adjustable) {
+            return;
+        }
+
+        $cart->adjustments()->deleteByType(AdjustmentTypeProxy::TAX());
+
+        if (null !== $this->rateResolver) {
+            $taxes = [];
+            /** @var CartItem $item */
+            foreach ($cart->getItems() as $item) {
+                if ($rate = $this->rateResolver->findTaxRate($item)) {
+                    $calculator = $rate->getCalculator();
+                    if ($adjuster = $calculator->getAdjuster($rate->configuration())) {
+                        /** @var Adjustment|null $adjustment */
+                        if ($adjustment = $cart->adjustments()?->create($adjuster)) {
+                            $taxes[$adjustment->getTitle()] = ($taxes[$adjustment->getTitle()] ?? 0) + $adjustment->getAmount();
+                        }
+                    }
+                }
+            }
+            $checkout->setTaxesAmount(
+                DetailedAmount::fromArray(
+                    Arr::mapWithKeys($taxes, fn($amount, $title) => [['title' => $title, 'amount' => $amount]]),
+                ),
+            );
+        }
+    }
+}

src/Foundation/Providers/EventServiceProvider.php

@@ -20,6 +20,7 @@
 use Vanilo\Checkout\Events\ShippingAddressChanged;
 use Vanilo\Checkout\Events\ShippingMethodSelected;
 use Vanilo\Foundation\Listeners\CalculateShippingFees;
+use Vanilo\Foundation\Listeners\CalculateTaxes;
 use Vanilo\Foundation\Listeners\DeleteCartAdjustments;
 use Vanilo\Foundation\Listeners\UpdateSalesFigures;
 use Vanilo\Order\Events\OrderWasCreated;
@@ -35,9 +36,11 @@ class EventServiceProvider extends ServiceProvider
         ],
         ShippingAddressChanged::class => [
             CalculateShippingFees::class,
+            CalculateTaxes::class,
         ],
         CartUpdated::class => [
             CalculateShippingFees::class,
+            CalculateTaxes::class,
         ],
         CartDeleting::class => [
             DeleteCartAdjustments::class,

src/Foundation/Tests/Examples/ExampleTaxCalculator.php

@@ -0,0 +1,55 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Contains the ExampleTaxCalculator class.
+ *
+ * @copyright   Copyright (c) 2024 Vanilo UG
+ * @author      Attila Fulop
+ * @license     MIT
+ * @since       2024-02-26
+ *
+ */
+
+namespace Vanilo\Foundation\Tests\Examples;
+
+use Nette\Schema\Expect;
+use Nette\Schema\Schema;
+use Vanilo\Adjustments\Adjusters\SimpleTax;
+use Vanilo\Contracts\DetailedAmount;
+use Vanilo\Taxes\Contracts\TaxCalculator;
+
+class ExampleTaxCalculator implements TaxCalculator
+{
+    public static function getName(): string
+    {
+        return 'Example';
+    }
+
+    public function getAdjuster(?array $configuration = null): ?object
+    {
+        $rate = floatval($configuration['rate'] ?? 0);
+        $adjuster = new SimpleTax($rate, false);
+        $adjuster->setTitle("$rate%");
+
+        return $adjuster;
+    }
+
+    public function calculate(?object $subject = null, ?array $configuration = null): DetailedAmount
+    {
+        $rate = floatval($configuration['rate'] ?? 0);
+
+        return \Vanilo\Support\Dto\DetailedAmount::fromArray([['title' => "$rate%", 'amount' => $subject->itemsTotal() * $rate / 100]]);
+    }
+
+    public function getSchema(): Schema
+    {
+        return Expect::structure(['rate' => Expect::float(0)->required()]);
+    }
+
+    public function getSchemaSample(array $mergeWith = null): array
+    {
+        return ['rate' => 19];
+    }
+}

src/Foundation/Tests/Examples/ExampleTaxEngine.php

@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Contains the ExampleTaxEngine class.
+ *
+ * @copyright   Copyright (c) 2024 Vanilo UG
+ * @author      Attila Fulop
+ * @license     MIT
+ * @since       2024-02-26
+ *
+ */
+
+namespace Vanilo\Foundation\Tests\Examples;
+
+use Vanilo\Contracts\Address;
+use Vanilo\Taxes\Contracts\Taxable;
+use Vanilo\Taxes\Contracts\TaxRate;
+use Vanilo\Taxes\Contracts\TaxRateResolver;
+use Vanilo\Taxes\Models\TaxCategoryType;
+
+/**
+ * This is an example tax rate resolver
+ * dedicated for unit-test only with
+ * the following hard-coded logic
+ *  - physical products: 19%
+ *  - shipping: 7%
+ *  - everything else: 15%
+ */
+class ExampleTaxEngine implements TaxRateResolver
+{
+    public const ID = 'example';
+
+    public function findTaxRate(Taxable $taxable, ?Address $billingAddress = null, ?Address $shippingAddress = null): ?TaxRate
+    {
+        $rate = match ($taxable->getTaxCategory()->getType()->value()) {
+            TaxCategoryType::PHYSICAL_GOODS => 19,
+            TaxCategoryType::TRANSPORT_SERVICES => 7,
+            default => 15,
+        };
+
+        return \Vanilo\Taxes\Models\TaxRate::firstOrCreate([
+            'rate' => $rate,
+            'name' => "$rate%",
+            'calculator' => 'example',
+            'configuration' => ['rate' => $rate],
+        ]);
+    }
+}

src/Foundation/Tests/TaxCalculationTest.php

@@ -0,0 +1,90 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Contains the TaxCalculationTest class.
+ *
+ * @copyright   Copyright (c) 2024 Vanilo UG
+ * @author      Attila Fulop
+ * @license     MIT
+ * @since       2024-02-26
+ *
+ */
+
+namespace Vanilo\Foundation\Tests;
+
+use Vanilo\Adjustments\Contracts\AdjustmentCollection;
+use Vanilo\Adjustments\Models\AdjustmentType;
+use Vanilo\Cart\Facades\Cart;
+use Vanilo\Checkout\Facades\Checkout;
+use Vanilo\Foundation\Models\Product;
+use Vanilo\Foundation\Tests\Examples\ExampleTaxCalculator;
+use Vanilo\Foundation\Tests\Examples\ExampleTaxEngine;
+use Vanilo\Taxes\Facades\TaxEngine;
+use Vanilo\Taxes\Models\TaxCategory;
+use Vanilo\Taxes\Models\TaxCategoryType;
+use Vanilo\Taxes\Resolver\TaxEngineManager;
+use Vanilo\Taxes\TaxCalculators;
+
+class TaxCalculationTest extends TestCase
+{
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        TaxEngine::extend(ExampleTaxEngine::ID, ExampleTaxEngine::class);
+        TaxCalculators::register('example', ExampleTaxCalculator::class);
+    }
+
+    /** @test */
+    public function no_tax_adjustment_gets_created_if_there_is_no_tax_engine_configured()
+    {
+        $product = factory(Product::class)->create();
+        config(['vanilo.taxes.engine.driver' => null]);
+
+        Cart::addItem($product);
+        Checkout::setCart(Cart::getFacadeRoot());
+
+        $this->assertCount(0, Cart::adjustments()->byType(AdjustmentType::TAX()));
+        $this->assertEquals(Cart::itemsTotal(), Cart::total());
+    }
+
+    /** @test */
+    public function no_tax_adjustment_gets_created_if_the_null_driver_is_set()
+    {
+        $product = factory(Product::class)->create();
+        config(['vanilo.taxes.engine.driver' => TaxEngineManager::NULL_DRIVER]);
+
+        Cart::addItem($product);
+        Checkout::setCart(Cart::getFacadeRoot());
+
+        $this->assertCount(0, Cart::adjustments()->byType(AdjustmentType::TAX()));
+        $this->assertEquals(Cart::itemsTotal(), Cart::total());
+    }
+
+    /** @test */
+    public function it_creates_a_tax_adjustment_when_setting_a_tax_engine()
+    {
+        $taxCategory = TaxCategory::create([
+            'name' => 'Physical products',
+            'type' => TaxCategoryType::PHYSICAL_GOODS,
+            'calculator' => 'example'
+        ]);
+        $product = factory(Product::class)->create(['price' => 100, 'tax_category_id' => $taxCategory->id]);
+        config(['vanilo.taxes.engine.driver' => ExampleTaxEngine::ID]);
+
+        Cart::addItem($product);
+        Checkout::setCart(Cart::getFacadeRoot());
+
+        /** @var AdjustmentCollection $taxAdjustments */
+        $taxAdjustments = Cart::adjustments()->byType(AdjustmentType::TAX());
+        $this->assertCount(1, $taxAdjustments);
+        $taxAdjustment = $taxAdjustments->first();
+        $this->assertEquals(19, $taxAdjustment->getAmount());
+        $this->assertTrue($taxAdjustment->isCharge());
+        $this->assertFalse($taxAdjustment->isIncluded());
+        $this->assertEquals(100, Cart::itemsTotal());
+        $this->assertEquals(100 + 19, Cart::total());
+    }
+}