Provide configuration settings for MailChimp Sign Up blocks to customize displaying of fields.

mailchimp-signup-block-customize-field-display.patch

diff --git a/modules/mailchimp_signup/src/Plugin/Block/MailchimpSignupSubscribeBlock.php b/modules/mailchimp_signup/src/Plugin/Block/MailchimpSignupSubscribeBlock.php
index 1798344..3ff60c9 100644
--- a/modules/mailchimp_signup/src/Plugin/Block/MailchimpSignupSubscribeBlock.php
+++ b/modules/mailchimp_signup/src/Plugin/Block/MailchimpSignupSubscribeBlock.php
@@ -9,6 +9,8 @@ use Drupal\Core\Messenger\MessengerInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Drupal\mailchimp_signup\Entity\MailchimpSignup;
 use Symfony\Component\DependencyInjection\ContainerInterface;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Component\Utility\NestedArray;
 
 /**
  * Provides a 'Subscribe' block.
@@ -93,6 +95,27 @@ class MailchimpSignupSubscribeBlock extends BlockBase implements ContainerFactor
 
     $content = $this->formBuilder->getForm($form);
 
+    foreach ($this->configuration['mergefield_settings'] as $field => $settings) {
+      if (empty($content['mergevars'][$field])) {
+        continue;
+      }
+      $content['mergevars'][$field]['#weight'] = $settings['weight'];
+      $content['mergevars'][$field]['#title_display'] = $settings['label_display'] ?? ($content['mergevars'][$field]['#title_display'] ?? 'before');
+
+      $attributes = static::getAttributesFromConfig($settings['other_attributes'] ?? '');
+      if (!empty(trim($settings['classes']))) {
+        $attributes['class'] = [trim($settings['classes'])];
+      }
+      $content['mergevars'][$field]['#attributes'] = NestedArray::mergeDeep($content['mergevars'][$field]['#attributes'] ?? [], $attributes);
+
+      if (!empty(trim($settings['wrapper_classes']))) {
+        if (!isset($content['mergevars'][$field]['#wrapper_attributes']['class'])) {
+          $content['mergevars'][$field]['#wrapper_attributes']['class'] = [];
+        }
+        $content['mergevars'][$field]['#wrapper_attributes']['class'][] = trim($settings['wrapper_classes']);
+      }
+    }
+
     return $content;
   }
 
@@ -125,4 +148,147 @@ class MailchimpSignupSubscribeBlock extends BlockBase implements ContainerFactor
     return $id;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function defaultConfiguration() {
+    return [
+      'mergefield_settings' => [],
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function blockForm($form, FormStateInterface $form_state) {
+    $signup_id = $this->getDerivativeId();
+    /* @var $signup \Drupal\mailchimp_signup\Entity\MailchimpSignup */
+    $signup = mailchimp_signup_load($signup_id);
+
+    $table = [
+      '#type' => 'table',
+      '#title' => $this->t('Merge Field Settings'),
+      '#caption' => $this->t('You may customize order of merge fields and provide additional classes.'),
+      '#header' => [
+        $this->t('Field'),
+        $this->t('Weight'),
+        $this->t('Label Display'),
+        $this->t('Field Classes'),
+        $this->t('Wrapper Classes'),
+        $this->t('Other attributes'),
+      ],
+      '#regions' => [],
+      '#attributes' => [
+        'class' => ['field-ui-overview'],
+        'id' => 'field-display-overview',
+      ],
+      '#tabledrag' => [
+        [
+          'action' => 'order',
+          'relationship' => 'sibling',
+          'group' => 'field-order',
+        ],
+      ],
+    ];
+
+    foreach ($signup->mergefields as $mergefield => $enabled) {
+      if (!$enabled) {
+        continue;
+      }
+
+      $settings = $this->configuration['mergefield_settings'][$mergefield] ?? [];
+
+      $table[$mergefield]['field'] = [
+        '#type' => 'markup',
+        '#markup' => $mergefield,
+      ];
+
+      $table[$mergefield]['#attributes']['class'] = ['draggable'];
+      $table[$mergefield]['weight'] = [
+        '#type' => 'weight',
+        '#title' => t('Weight'),
+        '#title_display' => 'invisible',
+        '#default_value' => $settings['weight'] ?? 0,
+        '#attributes' => [
+          'class' => [
+            'field-order'
+          ]
+        ],
+      ];
+
+      $table[$mergefield]['label_display'] = [
+        '#type' => 'select',
+        '#title' => $this->t('Label Display'),
+        '#title_display' => 'invisible',
+        '#options' => [
+          'before' => $this->t('Before'),
+          'after' => $this->t('After'),
+          'invisible' => $this->t('Invisible'),
+        ],
+        '#default_value' => $settings['label_display'] ?? 'before',
+      ];
+
+      $table[$mergefield]['classes'] = [
+        '#type' => 'textfield',
+        '#title' => $this->t('Classes'),
+        '#title_display' => 'invisible',
+        '#default_value' => $settings['classes'] ?? '',
+      ];
+      $table[$mergefield]['wrapper_classes'] = [
+        '#type' => 'textfield',
+        '#title' => $this->t('Wrapper Classes'),
+        '#title_display' => 'invisible',
+        '#default_value' => $settings['wrapper_classes'] ?? '',
+      ];
+
+      $table[$mergefield]['other_attributes'] = [
+        '#type' => 'textarea',
+        '#title' => $this->t('Other Attributes'),
+        '#title_display' => 'invisible',
+        '#default_value' => $settings['other_attributes'] ?? '',
+        '#description' => $this->t('Set attributes for this wrapper. Enter one value per line, in the format attribute|value. The value is optional. Tokens are supported in attribute values.'),
+      ];
+    }
+
+    $form['mergefield_settings'] = $table;
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function blockSubmit($form, FormStateInterface $form_state) {
+    $this->configuration['mergefield_settings'] = $form_state->getValue('mergefield_settings');
+  }
+
+  /**
+   * Convert multiline configuration for HTML attributes to array
+   *
+   * @param $attributes_string string
+   * @return array
+  */
+  public static function getAttributesFromConfig($attributes_string) {
+    // Split by new line.
+    $attribute_list = explode("\n", $attributes_string);
+    // Trim white spaces.
+    $attribute_list = array_map('trim', $attribute_list);
+    // Remove empty lines.
+    $attribute_list = array_filter($attribute_list, 'strlen');
+
+    $attributes = [];
+    foreach ($attribute_list as $text) {
+      // Check for an explicit key.
+      $matches = [];
+      if (preg_match('/^([\w]+(\-[\w]+)*)\|(.*)$/', $text, $matches)) {
+        // Trim key and value to avoid unwanted spaces issues.
+        $key = trim($matches[1]);
+        $value = trim($matches[3]);
+
+        $attributes[$key] = \Drupal::token()->replace($value, [], ['clear' => TRUE]);
+      }
+    }
+    return $attributes;
+  }
+
 }