[FEATURE] #22 Added dynamic shipping tax class calculation

Model/Config.php

@@ -15,6 +15,9 @@
  */
 class Config implements ConfigInterface
 {
+    const DYNAMIC_TYPE_DEFAULT = 0;
+    const DYNAMIC_TYPE_HIGHEST_PRODUCT_TAX = 1;
+
     /**
      * Configuration reader
      *

Model/System/Config/Source/Tax/Dynamic.php

@@ -0,0 +1,46 @@
+<?php
+/**
+ * Copyright © 2016 FireGento e.V.
+ * See LICENSE.md bundled with this module for license details.
+ */
+namespace FireGento\MageSetup\Model\System\Config\Source\Tax;
+
+use FireGento\MageSetup\Model\Config;
+
+/**
+ * Class Dynamic
+ *
+ * @package FireGento\MageSetup\Model\System\Config\Source\Tax
+ */
+class Dynamic implements \Magento\Framework\Option\ArrayInterface
+{
+    /**
+     * @var array
+     */
+    protected $options = null;
+
+    /**
+     * To option array
+     *
+     * @return array
+     */
+    public function toOptionArray()
+    {
+        if (null === $this->options) {
+            $options = [
+                [
+                    'value' => Config::DYNAMIC_TYPE_DEFAULT,
+                    'label' => __('No dynamic shipping tax caluclation')
+                ],
+                [
+                    'value' => Config::DYNAMIC_TYPE_HIGHEST_PRODUCT_TAX,
+                    'label' => __('Use the highest product tax')
+                ]
+            ];
+
+            $this->options = $options;
+        }
+
+        return $this->options;
+    }
+}

Plugin/Tax/Config/AroundGetShippingTaxClassPlugin.php

@@ -0,0 +1,167 @@
+<?php
+/**
+ * Copyright © 2016 FireGento e.V.
+ * See LICENSE.md bundled with this module for license details.
+ */
+namespace FireGento\MageSetup\Plugin\Tax\Config;
+
+use Magento\Store\Model\Store;
+use FireGento\MageSetup\Model\Config;
+
+/**
+ * Class AroundGetShippingTaxClassPlugin
+ *
+ * @package FireGento\MageSetup\Plugin\Tax\Config
+ */
+class AroundGetShippingTaxClassPlugin
+{
+    const CONFIG_PATH_DYNAMIC_SHIPPING_TAX_CLASS = 'tax/classes/dynamic_shipping_tax_class';
+
+    /**
+     * @var \Magento\Framework\App\Config\ScopeConfigInterface
+     */
+    private $scopeConfig;
+
+    /**
+     * @var \Magento\Checkout\Model\Cart
+     */
+    private $cart;
+    /**
+     * @var \Magento\Customer\Model\Session
+     */
+    private $customerSession;
+    /**
+     * @var \Magento\Customer\Model\ResourceModel\GroupRepository
+     */
+    private $groupRepository;
+    /**
+     * @var \Magento\Tax\Model\Calculation\Proxy
+     */
+    private $taxCalculation;
+
+    /**
+     * AroundGetShippingTaxClassPlugin constructor.
+     *
+     * @param \Magento\Framework\App\Config\ScopeConfigInterface    $scopeConfig
+     * @param \Magento\Checkout\Model\Cart                          $cart
+     * @param \Magento\Customer\Model\Session                       $customerSession
+     * @param \Magento\Customer\Model\ResourceModel\GroupRepository $groupRepository
+     * @param \Magento\Tax\Model\Calculation\Proxy                  $taxCalculation
+     */
+    public function __construct(
+        \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig,
+        \Magento\Checkout\Model\Cart $cart,
+        \Magento\Customer\Model\Session $customerSession,
+        \Magento\Customer\Model\ResourceModel\GroupRepository $groupRepository,
+        \Magento\Tax\Model\Calculation\Proxy $taxCalculation
+    )
+    {
+        $this->scopeConfig = $scopeConfig;
+        $this->cart = $cart;
+        $this->customerSession = $customerSession;
+        $this->groupRepository = $groupRepository;
+        $this->taxCalculation = $taxCalculation;
+    }
+
+    /**
+     * @param \Magento\Tax\Model\Config  $subject
+     * @param \Closure                   $proceed
+     * @param null|string|bool|int|Store $store
+     * @return mixed
+     */
+    public function aroundGetShippingTaxClass(\Magento\Tax\Model\Config $subject, \Closure $proceed, $store)
+    {
+        $handle = \fopen('abc.log', 'w+');
+
+        $dynamicType = (int)$this->scopeConfig->getValue(
+            self::CONFIG_PATH_DYNAMIC_SHIPPING_TAX_CLASS,
+            \Magento\Store\Model\ScopeInterface::SCOPE_STORE,
+            $store
+        );
+
+        // TODO: Check for admin quote
+
+        $quoteItems = $this->cart->getItems();
+
+        // If the default behaviour was configured or there are no products in cart, use default tax class id
+        if ($dynamicType == Config::DYNAMIC_TYPE_DEFAULT || count($quoteItems) == 0) {
+            return $proceed($store);
+        }
+
+        $taxClassId = false;
+
+        // Retrieve the highest product tax class
+        if ($dynamicType == Config::DYNAMIC_TYPE_HIGHEST_PRODUCT_TAX) {
+            $taxClassId = $this->getHighestProductTaxClassId($quoteItems, $store);
+        }
+
+        // If no tax class id was found, use default one
+        if (!$taxClassId) {
+            $taxClassId = $proceed($store);
+        }
+
+        return $taxClassId;
+    }
+
+    /**
+     * @param array                      $quoteItems
+     * @param null|string|bool|int|Store $store
+     * @return bool|mixed|null
+     */
+    private function getHighestProductTaxClassId($quoteItems, $store)
+    {
+        $taxClassIds = [];
+        $highestTaxRate = null;
+
+        foreach ($quoteItems as $quoteItem) {
+            /** @var $quoteItem \Magento\Quote\Model\Quote\Item */
+            if ($quoteItem->getParentItem()) {
+                continue;
+            }
+
+            // Retrieve the tax percent
+            $taxPercent = $quoteItem->getTaxPercent();
+            if (!$taxPercent) {
+                $taxPercent = $this->getTaxPercent($quoteItem->getTaxClassId(), $store);
+            }
+
+            // Add the tax class
+            if (is_float($taxPercent) && !in_array($taxPercent, $taxClassIds)) {
+                $taxClassIds[$taxPercent] = $quoteItem->getTaxClassId();
+            }
+        }
+
+        // Fetch the highest tax rate
+        ksort($taxClassIds);
+        if (count($taxClassIds) > 0) {
+            $highestTaxRate = array_pop($taxClassIds);
+        }
+        if (!$highestTaxRate || is_null($highestTaxRate)) {
+            return false;
+        }
+
+        return $highestTaxRate;
+    }
+
+    /**
+     * @param int                        $productTaxClassId
+     * @param null|string|bool|int|Store $store
+     * @return float|int
+     */
+    private function getTaxPercent($productTaxClassId, $store)
+    {
+        $groupId = $this->customerSession->getCustomerGroupId();
+        $group = $this->groupRepository->getById($groupId);
+        $customerTaxClassId = $group->getTaxClassId();
+
+        $request = $this->taxCalculation->getRateRequest(null, null, $customerTaxClassId, $store);
+        $request->setData('product_class_id', $productTaxClassId);
+
+        $taxPercent = $this->taxCalculation->getRate($request);
+        if (!$taxPercent) {
+            $taxPercent = 0;
+        }
+
+        return $taxPercent;
+    }
+}

etc/adminhtml/system.xml

@@ -136,5 +136,13 @@
                 </field>
             </group>
         </section>
+        <section id="tax">
+            <group id="classes">
+                <field id="dynamic_shipping_tax_class" translate="label" type="select" sortOrder="11" showInDefault="1" showInWebsite="1" showInStore="0">
+                    <label>Dynamic Shipping Tax Class</label>
+                    <source_model>FireGento\MageSetup\Model\System\Config\Source\Tax\Dynamic</source_model>
+                </field>
+            </group>
+        </section>
     </system>
 </config>

etc/di.xml

@@ -43,4 +43,8 @@
     <type name="Magento\CheckoutAgreements\Model\Agreement">
         <plugin name="mageSetupFilterAgreementContent" type="FireGento\MageSetup\Plugin\Agreements\AfterGetContent" sortOrder="1"/>
     </type>
+
+    <type name="Magento\Tax\Model\Config">
+        <plugin name="mageSetupDynamicShippingTaxClass" type="FireGento\MageSetup\Plugin\Tax\Config\AroundGetShippingTaxClassPlugin" sortOrder="1"/>
+    </type>
 </config>