first upload all files

Modules/Cart/CartTax.php

@@ -0,0 +1,77 @@
+<?php
+
+namespace Modules\Cart;
+
+use JsonSerializable;
+use Modules\Support\Money;
+
+class CartTax implements JsonSerializable
+{
+    private $cart;
+    private $taxRate;
+    private $taxCondition;
+
+    public function __construct($cart, $taxRate, $taxCondition)
+    {
+        $this->cart = $cart;
+        $this->taxRate = $taxRate;
+        $this->taxCondition = $taxCondition;
+    }
+
+    public function id()
+    {
+        return $this->taxRate->id;
+    }
+
+    public function name()
+    {
+        return $this->taxRate->name;
+    }
+
+    public function amount()
+    {
+        return Money::inDefaultCurrency($this->calculate());
+    }
+
+    private function calculate()
+    {
+        return $this->taxCondition->getCalculatedValue($this->productsTotalPrice());
+    }
+
+    private function productsTotalPrice()
+    {
+        return $this->taxApplicableProducts()->sum(function ($cartItem) {
+            return $cartItem->total()->amount();
+        });
+    }
+
+    private function taxApplicableProducts()
+    {
+        return $this->cart->items()->filter(function ($cartItem) {
+            return $this->hasMatchingTaxClass($cartItem);
+        });
+    }
+
+    private function hasMatchingTaxClass($cartItem)
+    {
+        return $cartItem->product->tax_class_id === $this->taxRate->tax_class_id;
+    }
+
+    public function toArray()
+    {
+        return [
+            'name' => $this->name(),
+            'amount' => $this->amount(),
+        ];
+    }
+
+    public function jsonSerialize()
+    {
+        return $this->toArray();
+    }
+
+    public function __toString()
+    {
+        return json_encode($this->jsonSerialize());
+    }
+}