[WIP] Group field type and formatter

og.module

@@ -7,6 +7,8 @@
 use Drupal\Core\Access\AccessResult;
 use Drupal\Core\Entity\ContentEntityInterface;
 use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Entity\EntityTypeInterface;
+use Drupal\Core\Field\BaseFieldDefinition;
 use Drupal\Core\Session\AccountInterface;
 use Drupal\og\Entity\OgRoleInterface;
 use Drupal\og\Og;
@@ -181,6 +183,29 @@ function og_entity_create_access(AccountInterface $account, array $context, $bun
   return $required ? AccessResult::forbiddenIf($node_access_strict) : AccessResult::neutral();
 }
 
+/**
+ *
+ * Implements hook_entity_bundle_field_info().
+ *
+ * Add a read only property to group entities as a group flag.
+ */
+function og_entity_bundle_field_info(EntityTypeInterface $entity_type, $bundle, array $base_field_definitions) {
+  if (!Og::isGroup($entity_type->id(), $bundle)) {
+    return NULL;
+  }
+
+  $fields = [];
+
+  $fields['og_group'] = BaseFieldDefinition::create('og_group')
+    ->setLabel(t('OG Group'))
+    ->setComputed(TRUE)
+    ->setTranslatable(FALSE)
+    ->setDefaultValue(TRUE)
+    ->setReadOnly(TRUE);
+
+  return $fields;
+}
+
 /**
  * Implements hook_help().
  */

og_ui/og_ui.module

@@ -1,4 +1,5 @@
 <?php
+
 /**
  * @file
  * Main functions and hook implementations of the Organic Groups UI module.
@@ -7,6 +8,7 @@
 use Drupal\Core\Config\Entity\ConfigEntityBundleBase;
 use Drupal\Core\Entity\BundleEntityFormBase;
 use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Entity\EntityTypeInterface;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\field\Entity\FieldConfig;
 use Drupal\og\Og;
@@ -91,3 +93,16 @@ function og_ui_entity_type_save(EntityInterface $entity) {
     }
   }
 }
+
+/**
+ * Implements hook_entity_bundle_field_info_alter().
+ *
+ * Set the default field formatter of fields of type OG group.
+ */
+function og_ui_entity_bundle_field_info_alter(&$fields, EntityTypeInterface $entity_type, $bundle) {
+  if (isset($fields['og_group'])) {
+    $fields['og_group']->setDisplayOptions('view', [
+      'type' => 'og_ui_group_subscribe',
+    ])->setDisplayConfigurable('view', TRUE);
+  }
+}

og_ui/src/Plugin/Field/FieldFormatter/GroupSubscribeFormatter.php

@@ -0,0 +1,255 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\og_ui\Plugin\Field\FieldFormatter\GroupSubscribeFormatter.
+ */
+
+namespace Drupal\og_ui\Plugin\Field\FieldFormatter;
+
+
+use Drupal\Core\Access\AccessResult;
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Field\FieldItemListInterface;
+use Drupal\Core\Field\FormatterBase;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Routing\RedirectDestinationTrait;
+use Drupal\Core\Url;
+use Drupal\og\Og;
+use Drupal\og\OgAccess;
+use Drupal\og\OgGroupAudienceHelper;
+use Drupal\user\Entity\User;
+use Drupal\user\EntityOwnerInterface;
+
+/**
+ * Plugin implementation for the OG subscribe formatter.
+ *
+ * @FieldFormatter(
+ *   id = "og_ui_group_subscribe",
+ *   label = @Translation("OG Group subscribe"),
+ *   description = @Translation("Display OG Group subscribe links."),
+ *   field_types = {
+ *     "og_group"
+ *   }
+ * )
+ */
+class GroupSubscribeFormatter extends FormatterBase {
+
+  use RedirectDestinationTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function viewElements(FieldItemListInterface $items, $langcode) {
+    $elements = [];
+
+    $entity = $items->getEntity();
+    $entity_type_id = $entity->getEntityTypeId();
+    $bundle_id = $entity->bundle();
+
+    $account = User::load(\Drupal::currentUser()->id());
+    $field_name = $this->getSetting('field_name');
+
+    // Entity is not a group.
+    if (!Og::isGroup($entity->getEntityTypeId(), $entity->bundle())) {
+      return [];
+    }
+
+    if (($entity instanceof EntityOwnerInterface) && ($entity->getOwnerId() == $account->id())) {
+      // User is the group manager.
+      $elements[0] = [
+        '#type' => 'html_tag',
+        '#tag' => 'span',
+        '#attributes' => [
+          'title' => $this->t('You are the group manager'),
+          'class' => ['group', 'manager'],
+        ],
+        '#value' => $this->t('You are the group manager'),
+      ];
+
+      return $elements;
+    }
+
+    if (Og::isMember($entity, $account, [OG_STATE_ACTIVE, OG_STATE_PENDING])) {
+      if (OgAccess::userAccess($entity, 'unsubscribe', $account)) {
+        $link['title'] = $this->t('Unsubscribe from group');
+        $link['url'] = Url::fromRoute('og_ui.unsubscribe', ['entity_type_id' => $entity_type_id, 'entity_id' => $entity->id()]);
+        $link['class'] = ['unsubscribe'];
+      }
+    }
+    else {
+      if (Og::isMember($entity, $account, [OG_STATE_BLOCKED])) {
+        // If user is blocked, they should not be able to apply for
+        // membership.
+        return [];
+      }
+
+      // Check if user can subscribe to the field.
+      if (empty($field_name) && ($audience_field_name = OgGroupAudienceHelper::getMatchingField($account, $entity_type_id, $bundle_id))) {
+        $field_name = $audience_field_name;
+      }
+
+      if (empty($field_name)) {
+        return [];
+      }
+
+      // Check if entity is referencable.
+      if ($this->getSetting('target_type') !== $entity->getEntityTypeId()) {
+        // Group type doesn't match.
+        return [];
+      }
+
+      // Check handler bundles, if any.
+      $handler_settings = $this->getSetting('handler_settings');
+
+      if (!empty($handler_settings['target_bundles']) && !in_array($bundle_id, $handler_settings['target_bundles'])) {
+        // Bundles don't match.
+        return [];
+      }
+
+      if (!OgGroupAudienceHelper::checkFieldCardinality($account, $field_name)) {
+        $cardinality = $this->fieldDefinition->getFieldStorageDefinition()->getCardinality();
+
+        $elements[0] = [
+          '#type' => 'html_tag',
+          '#tag' => 'span',
+          '#attributes' => [
+            'title' => $this->formatPlural($cardinality, 'You are already registered to another group', 'You are already registered to @count groups'),
+            'class' => ['group', 'other'],
+          ],
+          '#value' => $this->formatPlural($cardinality, 'You are already registered to another group', 'You are already registered to @count groups'),
+        ];
+
+        return $elements;
+      }
+
+      // If hte user is authenticated, set up the subscribe link.
+      if ($account->isAuthenticated()) {
+        $parameters = [
+          'entity_type_id' => $entity->getEntityTypeId(),
+          'entity_id' => $entity->id(),
+        ];
+
+        // Add the field name as an additional query parameter.
+        if (!empty($field_name)) {
+          $parameters['field_name'] = $field_name;
+        }
+
+        $url = Url::fromRoute('og_ui.subscribe', $parameters);
+      }
+      // Otherwise, link to user login and redirect back to here.
+      else {
+        $url = Url::fromRoute('user.login', [], ['query' => $this->getDestinationArray()]);
+      }
+
+      if (OgAccess::userAccess($entity, 'subscribe without approval', $account)) {
+        $link['title'] = $this->t('Subscribe to group');
+        $link['class'] = ['subscribe'];
+        $link['url'] = $url;
+      }
+      elseif (OgAccess::userAccess($entity, 'subscribe')) {
+        $link['title'] = $this->t('Request group membership');
+        $link['class'] = ['subscribe', 'request'];
+        $link['url'] = $url;
+      }
+      else {
+        $elements[0] = [
+          '#type' => 'html_tag',
+          '#tag' => 'span',
+          '#attributes' => [
+            'title' => $this->t('This is a closed group. Only a group administrator can add you.'),
+            'class' => ['group', 'closed'],
+          ],
+          '#value' => $this->t('This is a closed group. Only a group administrator can add you.'),
+        ];
+
+        return $elements;
+      }
+    }
+
+    if (!empty($link['title'])) {
+      $link += [
+        'options' => [
+          'attributes' => [
+            'title' => $link['title'],
+            'class' => ['group'] + $link['class'],
+          ],
+        ],
+      ];
+
+      $elements[0] = [
+        '#type' => 'link',
+        '#title' => $link['title'],
+        '#url' => $link['url'],
+      ];
+    }
+
+    return $elements;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function defaultSettings() {
+    $options = parent::defaultSettings();
+
+    $options['field_name'] = 0;
+
+    return $options;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsForm(array $form, FormStateInterface $form_state) {
+    $form = parent::settingsForm($form, $form_state);
+
+    $form['field_name'] = [
+      '#title' => $this->t('Field name'),
+      '#description' => $this->t('Select the field that should register the user subscription.'),
+      '#type' => 'select',
+      '#options' => $this->getAudienceFieldOptions(),
+      '#default_value' => $this->getSetting('field_name'),
+    ];
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsSummary() {
+    $summary = parent::settingsSummary();
+    $options = $this->getAudienceFieldOptions();
+
+    $field_name = $this->getSetting('field_name');
+
+    $summary[] = $this->t('Field: %label', array('%label' => $options[$field_name]));
+
+    return $summary;
+  }
+
+  /**
+   * Returns audience field options.
+   *
+   * @return array
+   *   An array of audience field options.
+   */
+  protected function getAudienceFieldOptions() {
+    $options = [0 => $this->t('Automatic (best matching)')];
+
+    foreach (Og::getAllGroupAudienceFields('user', 'user') as $field_name => $field_definition) {
+      $options[$field_name] = $field_definition->getLabel();
+    }
+
+    return $options;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function checkAccess(EntityInterface $entity) {
+    return AccessResult::allowed();
+  }
+
+}

src/OgGroupBoolean.php

@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\og\OgGroupBoolean.
+ */
+
+namespace Drupal\og;
+
+use Drupal\Core\TypedData\Plugin\DataType\BooleanData;
+
+/**
+ * Overridden boolean data type to hardcode TRUE.
+ */
+class OgGroupBoolean extends BooleanData {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getValue() {
+    return TRUE;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getCastedValue() {
+    return $this->getValue();
+  }
+
+}