[Improvement] Implement customer group form on ui component

app/code/Magento/Customer/Block/Adminhtml/Group/Edit/BackButton.php

@@ -0,0 +1,37 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\Customer\Block\Adminhtml\Group\Edit;
+
+use Magento\Framework\View\Element\UiComponent\Control\ButtonProviderInterface;
+
+/**
+ * Class BackButton
+ */
+class BackButton extends GenericButton implements ButtonProviderInterface
+{
+    /**
+     * @return array
+     */
+    public function getButtonData()
+    {
+        return [
+            'label' => __('Back'),
+            'on_click' => sprintf("location.href = '%s';", $this->getBackUrl()),
+            'class' => 'back',
+            'sort_order' => 10
+        ];
+    }
+
+    /**
+     * Get URL for back (reset) button
+     *
+     * @return string
+     */
+    public function getBackUrl()
+    {
+        return $this->getUrl('*/*/');
+    }
+}

app/code/Magento/Customer/Block/Adminhtml/Group/Edit/DeleteButton.php

@@ -0,0 +1,65 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\Customer\Block\Adminhtml\Group\Edit;
+
+use Magento\Framework\View\Element\UiComponent\Control\ButtonProviderInterface;
+
+/**
+ * Class DeleteButton
+ */
+class DeleteButton extends GenericButton implements ButtonProviderInterface
+{
+    /**
+     * @var \Magento\Customer\Api\GroupManagementInterface
+     */
+    protected $groupManagement;
+
+    /**
+     * Constructor
+     *
+     * @param \Magento\Backend\Block\Widget\Context $context
+     * @param \Magento\Framework\Registry $registry
+     * @param \Magento\Customer\Api\GroupManagementInterface $groupManagement
+     */
+    public function __construct(
+        \Magento\Backend\Block\Widget\Context $context,
+        \Magento\Framework\Registry $registry,
+        \Magento\Customer\Api\GroupManagementInterface $groupManagement
+    ) {
+        parent::__construct($context, $registry);
+        $this->groupManagement = $groupManagement;
+    }
+
+    /**
+     * @return array
+     */
+    public function getButtonData()
+    {
+        $groupId = $this->getGroupId();
+        $canModify = $groupId && !$this->groupManagement->isReadonly($this->getGroupId());
+        $data = [];
+        if ($canModify) {
+            $data = [
+                'label' => __('Delete Customer Group'),
+                'class' => 'delete',
+                'on_click' => 'deleteConfirm(\'' . __(
+                    'Are you sure you want to do this?'
+                ) . '\', \'' . $this->getDeleteUrl() . '\')',
+                'sort_order' => 20,
+            ];
+        }
+
+        return $data;
+    }
+
+    /**
+     * @return string
+     */
+    public function getDeleteUrl()
+    {
+        return $this->getUrl('*/*/delete', ['id' => $this->getGroupId()]);
+    }
+}

app/code/Magento/Customer/Block/Adminhtml/Group/Edit/GenericButton.php

@@ -0,0 +1,64 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\Customer\Block\Adminhtml\Group\Edit;
+
+use Magento\Customer\Controller\RegistryConstants;
+
+/**
+ * Class GenericButton
+ */
+class GenericButton
+{
+    /**
+     * Url Builder
+     *
+     * @var \Magento\Framework\UrlInterface
+     */
+    protected $urlBuilder;
+
+    /**
+     * Registry
+     *
+     * @var \Magento\Framework\Registry
+     */
+    protected $registry;
+
+    /**
+     * Constructor
+     *
+     * @param \Magento\Backend\Block\Widget\Context $context
+     * @param \Magento\Framework\Registry $registry
+     */
+    public function __construct(
+        \Magento\Backend\Block\Widget\Context $context,
+        \Magento\Framework\Registry $registry
+    ) {
+        $this->urlBuilder = $context->getUrlBuilder();
+        $this->registry = $registry;
+    }
+
+    /**
+     * Return the group Id.
+     *
+     * @return int|null
+     */
+    public function getGroupId()
+    {
+        return $this->registry->registry(RegistryConstants::CURRENT_GROUP_ID);
+    }
+
+    /**
+     * Generate url by route and parameters
+     *
+     * @param   string $route
+     * @param   array $params
+     * @return  string
+     */
+    public function getUrl($route = '', $params = [])
+    {
+        return $this->urlBuilder->getUrl($route, $params);
+    }
+}

app/code/Magento/Customer/Block/Adminhtml/Group/Edit/ResetButton.php

@@ -0,0 +1,27 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\Customer\Block\Adminhtml\Group\Edit;
+
+use Magento\Framework\View\Element\UiComponent\Control\ButtonProviderInterface;
+
+/**
+ * Class ResetButton
+ */
+class ResetButton extends GenericButton implements ButtonProviderInterface
+{
+    /**
+     * @return array
+     */
+    public function getButtonData()
+    {
+        return [
+            'label' => __('Reset'),
+            'class' => 'reset',
+            'on_click' => 'location.reload();',
+            'sort_order' => 30
+        ];
+    }
+}

app/code/Magento/Customer/Block/Adminhtml/Group/Edit/SaveAndContinueButton.php

@@ -0,0 +1,31 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\Customer\Block\Adminhtml\Group\Edit;
+
+use Magento\Framework\View\Element\UiComponent\Control\ButtonProviderInterface;
+
+/**
+ * Class SaveAndContinueButton
+ */
+class SaveAndContinueButton extends GenericButton implements ButtonProviderInterface
+{
+    /**
+     * @return array
+     */
+    public function getButtonData()
+    {
+        return [
+            'label' => __('Save and Continue Edit'),
+            'class' => 'save',
+            'data_attribute' => [
+                'mage-init' => [
+                    'button' => ['event' => 'saveAndContinueEdit'],
+                ],
+            ],
+            'sort_order' => 80,
+        ];
+    }
+}

app/code/Magento/Customer/Block/Adminhtml/Group/Edit/SaveButton.php

@@ -0,0 +1,30 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\Customer\Block\Adminhtml\Group\Edit;
+
+use Magento\Framework\View\Element\UiComponent\Control\ButtonProviderInterface;
+
+/**
+ * Class SaveButton
+ */
+class SaveButton extends GenericButton implements ButtonProviderInterface
+{
+    /**
+     * @return array
+     */
+    public function getButtonData()
+    {
+        return [
+            'label' => __('Save Customer Group'),
+            'class' => 'save primary',
+            'data_attribute' => [
+                'mage-init' => ['button' => ['event' => 'save']],
+                'form-role' => 'save',
+            ],
+            'sort_order' => 90,
+        ];
+    }
+}

app/code/Magento/Customer/Controller/Adminhtml/Group/NewAction.php

@@ -49,9 +49,6 @@ public function execute()
             );
         }
 
-        $resultPage->getLayout()->addBlock(\Magento\Customer\Block\Adminhtml\Group\Edit::class, 'group', 'content')
-            ->setEditMode((bool)$groupId);
-
         return $resultPage;
     }
 }

app/code/Magento/Customer/Controller/Adminhtml/Group/Save.php

@@ -69,16 +69,17 @@ protected function storeCustomerGroupDataToSession($customerGroupData)
      */
     public function execute()
     {
-        $taxClass = (int)$this->getRequest()->getParam('tax_class');
+        $taxClass = (int)$this->getRequest()->getParam('tax_class_id');
 
         /** @var \Magento\Customer\Api\Data\GroupInterface $customerGroup */
         $customerGroup = null;
         if ($taxClass) {
-            $id = $this->getRequest()->getParam('id');
+            $id = $this->getRequest()->getParam('customer_group_id');
+            /** @var \Magento\Backend\Model\View\Result\Redirect $resultRedirect */
             $resultRedirect = $this->resultRedirectFactory->create();
             try {
-                $customerGroupCode = (string)$this->getRequest()->getParam('code');
-                if ($id !== null) {
+                $customerGroupCode = (string)$this->getRequest()->getParam('customer_group_code');
+                if ($id !== null && $id !== '') {
                     $customerGroup = $this->groupRepository->getById((int)$id);
                     $customerGroupCode = $customerGroupCode ?: $customerGroup->getCode();
                 } else {
@@ -87,10 +88,14 @@ public function execute()
                 $customerGroup->setCode(!empty($customerGroupCode) ? $customerGroupCode : null);
                 $customerGroup->setTaxClassId($taxClass);
 
-                $this->groupRepository->save($customerGroup);
+                $customerGroup = $this->groupRepository->save($customerGroup);
 
                 $this->messageManager->addSuccess(__('You saved the customer group.'));
-                $resultRedirect->setPath('customer/group');
+                if ($this->getRequest()->getParam('back')) {
+                    $resultRedirect->setPath('customer/group/edit', ['id' => $customerGroup->getId()]);
+                } else {
+                    $resultRedirect->setPath('customer/group');
+                }
             } catch (\Exception $e) {
                 $this->messageManager->addError($e->getMessage());
                 if ($customerGroup != null) {