Add a view display extender for the localgov_page_header for the lede

Fix #127

Adds a setting to views that allows for a page header category, with the option
to set a custom lede inside the view, which will then be used by the
page header block.

config/schema/localgov_core.views.schema.yml

@@ -0,0 +1,9 @@
+views.display_extender.localgov_page_header_display_extender:
+  type: views_display_extender
+  mapping:
+    lede:
+      type: text
+      label: 'Lede'
+    tokenize:
+      type: boolean
+      label: 'Should replacement tokens be used from the first row'

src/Plugin/Block/PageHeaderBlock.php

@@ -14,6 +14,8 @@
 use Drupal\localgov_core\Event\PageHeaderDisplayEvent;
 use Drupal\node\Entity\Node;
 use Drupal\taxonomy\Entity\Term;
+use Drupal\views\ViewExecutable;
+use Drupal\views\Views;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\HttpFoundation\RequestStack;
 
@@ -130,6 +132,7 @@ public function __construct(array $configuration, $plugin_id, $plugin_definition
     $route = $this->currentRouteMatch->getRouteObject();
     if (!is_null($route)) {
       $parameters = $route->getOption('parameters');
+      $defaults = $route->getDefaults();
       if (!is_null($parameters)) {
         foreach ($parameters as $name => $options) {
           if (!isset($options['type'])) {
@@ -152,6 +155,13 @@ public function __construct(array $configuration, $plugin_id, $plugin_definition
           }
         }
       }
+      if (isset($defaults['view_id']) && isset($defaults['display_id'])) {
+        $view = Views::getView($defaults['view_id']);
+        if ($view) {
+          $view->setDisplay($defaults['display_id']);
+          $this->entity = $view;
+        }
+      }
     }
 
     // Dispatch event to allow modules to alter block content.
@@ -224,6 +234,18 @@ protected function getLede() {
       ];
     }
 
+    // Return view custom summary.
+    if ($this->entity instanceof ViewExecutable) {
+      $extender = $this->entity->getDisplay()->getExtenders()['localgov_page_header_display_extender'] ?? NULL;
+      $this->entity->render();
+      $lede = $extender->getLede();
+      return [
+        '#type' => 'html_tag',
+        '#tag' => 'p',
+        '#value' => $lede,
+      ];
+    }
+
     return NULL;
   }
 

src/Plugin/views/display_extender/PageHeaderDisplayExtender.php

@@ -0,0 +1,251 @@
+<?php
+
+namespace Drupal\localgov_core\Plugin\views\display_extender;
+
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+use Drupal\views\Plugin\views\display_extender\DisplayExtenderPluginBase;
+use Drupal\views\Plugin\views\style\StylePluginBase;
+use Drupal\views\ViewExecutable;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Metatag display extender plugin.
+ *
+ * @ingroup views_display_extender_plugins
+ *
+ * @ViewsDisplayExtender(
+ *   id = "localgov_page_header_display_extender",
+ *   title = @Translation("Page header display extender"),
+ *   help = @Translation("Page header settings for this view."),
+ *   no_ui = FALSE
+ * )
+ */
+class PageHeaderDisplayExtender extends DisplayExtenderPluginBase {
+
+  use StringTranslationTrait;
+
+  /**
+   * The first row tokens on the style plugin.
+   *
+   * @var array
+   */
+  protected static $firstRowTokens;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
+    /** @var \Drupal\metatag_views\Plugin\views\display_extender\MetatagDisplayExtender */
+    $instance = parent::create($container, $configuration, $plugin_id, $plugin_definition);
+
+    return $instance;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function defineOptions() {
+    $options = parent::defineOptions();
+
+    $options['lede'] = ['default' => ''];
+    $options['tokenize'] = ['default' => FALSE];
+
+    return $options;
+  }
+
+  /**
+   * Provide a form to edit options for this plugin.
+   */
+  public function buildOptionsForm(&$form, FormStateInterface $form_state) {
+
+    if ($form_state->get('section') == 'page_header') {
+      $form['#title'] .= $this->t('The page header summary');
+
+      // Build/inject the Metatag form.
+      $form['lede'] = [
+        '#type' => 'textarea',
+        '#title' => $this->t('Lede'),
+        '#description' => $this->t('Summary displayed under the page title.'),
+        '#default_value' => $this->options['lede'],
+      ];
+      $this->tokenForm($form['page_header'], $form_state);
+    }
+  }
+
+  /**
+   * Handle any special handling on the validate form.
+   */
+  public function submitOptionsForm(&$form, FormStateInterface $form_state) {
+    if ($form_state->get('section') == 'page_header') {
+      // Process submitted metatag values and remove empty tags.
+      $page_header_values = $form_state->cleanValues()->getValues();
+      $this->options['tokenize'] = $page_header_values['tokenize'] ?? FALSE;
+      unset($page_header_values['tokenize']);
+      $this->options['lede'] = $page_header_values['lede'];
+    }
+  }
+
+  /**
+   * Verbatim copy of TokenizeAreaPluginBase::tokenForm().
+   */
+  public function tokenForm(&$form, FormStateInterface $form_state) {
+    $form['tokenize'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('Use replacement tokens from the first row'),
+      '#default_value' => $this->options['tokenize'],
+    ];
+
+    // Get a list of the available fields and arguments for token replacement.
+    $options = [];
+    $optgroup_arguments = (string) new TranslatableMarkup('Arguments');
+    $optgroup_fields = (string) new TranslatableMarkup('Fields');
+    foreach ($this->view->display_handler->getHandlers('field') as $field => $handler) {
+      $options[$optgroup_fields]["{{ $field }}"] = $handler->adminLabel();
+    }
+
+    foreach ($this->view->display_handler->getHandlers('argument') as $arg => $handler) {
+      $options[$optgroup_arguments]["{{ arguments.$arg }}"] = $this->t('@argument title', ['@argument' => $handler->adminLabel()]);
+      $options[$optgroup_arguments]["{{ raw_arguments.$arg }}"] = $this->t('@argument input', ['@argument' => $handler->adminLabel()]);
+    }
+
+    if (!empty($options)) {
+      $form['tokens'] = [
+        '#type' => 'details',
+        '#title' => $this->t('Replacement patterns'),
+        '#open' => TRUE,
+        '#id' => 'edit-options-token-help',
+        '#states' => [
+          'visible' => [
+            ':input[name="options[tokenize]"]' => ['checked' => TRUE],
+          ],
+        ],
+      ];
+      $form['tokens']['help'] = [
+        '#markup' => '<p>' . $this->t('The following tokens are available. You may use Twig syntax in this field.') . '</p>',
+      ];
+      foreach (array_keys($options) as $type) {
+        if (!empty($options[$type])) {
+          $items = [];
+          foreach ($options[$type] as $key => $value) {
+            $items[] = $key . ' == ' . $value;
+          }
+          $form['tokens'][$type]['tokens'] = [
+            '#theme' => 'item_list',
+            '#items' => $items,
+          ];
+        }
+      }
+    }
+
+    $this->globalTokenForm($form, $form_state);
+  }
+
+  /**
+   * Provide the default summary for options in the views UI.
+   *
+   * This output is returned as an array.
+   */
+  public function optionsSummary(&$categories, &$options) {
+    $categories['page_header'] = [
+      'title' => $this->t('Page header'),
+      'column' => 'second',
+    ];
+    $options['page_header'] = [
+      'category' => 'page_header',
+      'title' => $this->t('Page header'),
+      'value' => $this->options['lede'] ? $this->t('Custom lede') : $this->t('No lede'),
+    ];
+  }
+
+  /**
+   * Lists defaultable sections and items contained in each section.
+   */
+  public function defaultableSections(&$sections, $section = NULL) {
+  }
+
+  /**
+   * Get the lede for display.
+   *
+   * @param bool $raw
+   *   Flag if to return raw (untokenised) output.
+   *
+   * @return string
+   *   Lede for display.
+   */
+  public function getLede(bool $raw = FALSE) : string {
+    $view = $this->view;
+    $lede = '';
+
+    if (!empty($this->options['lede'])) {
+      $lede = $this->options['lede'];
+    }
+
+    if ($this->options['lede'] && !$raw) {
+      if (!empty(self::$firstRowTokens[$view->current_display])) {
+        self::setFirstRowTokensOnStylePlugin($view, self::$firstRowTokens[$view->current_display]);
+      }
+      // This is copied from TokenizeAreaPluginBase::tokenizeValue().
+      $style = $view->getStyle();
+      $lede = $style->tokenizeValue($lede, 0);
+      $lede = $this->globalTokenReplace($lede);
+    }
+
+    return $lede;
+  }
+
+  /**
+   * Store first row tokens on the class.
+   *
+   * The function metatag_views_metatag_route_entity() loads the View fresh, to
+   * avoid rebuilding and re-rendering it, preserve the first row tokens.
+   */
+  public function setFirstRowTokens(array $first_row_tokens) {
+    self::$firstRowTokens[$this->view->current_display] = $first_row_tokens;
+  }
+
+  /**
+   * Set the first row tokens on the style plugin.
+   *
+   * @param \Drupal\views\ViewExecutable $view
+   *   The view.
+   * @param array $first_row_tokens
+   *   The first row tokens.
+   */
+  public static function setFirstRowTokensOnStylePlugin(ViewExecutable $view, array $first_row_tokens) {
+    $style = $view->getStyle();
+    self::getFirstRowTokensReflection($style)->setValue($style, [$first_row_tokens]);
+  }
+
+  /**
+   * Get the first row tokens from the style plugin.
+   *
+   * @param \Drupal\views\ViewExecutable $view
+   *   The view.
+   *
+   * @return array
+   *   The first row tokens.
+   */
+  public static function getFirstRowTokensFromStylePlugin(ViewExecutable $view) {
+    $style = $view->getStyle();
+    return self::getFirstRowTokensReflection($style)->getValue($style)[0] ?? [];
+  }
+
+  /**
+   * Get the first row tokens for this Views object iteration.
+   *
+   * @param \Drupal\views\Plugin\views\style\StylePluginBase $style
+   *   The style plugin used for this request.
+   *
+   * @return \ReflectionProperty
+   *   The rawTokens property.
+   */
+  protected static function getFirstRowTokensReflection(StylePluginBase $style): \ReflectionProperty {
+    $r = new \ReflectionObject($style);
+    $p = $r->getProperty('rowTokens');
+    $p->setAccessible(TRUE);
+    return $p;
+  }
+
+}