Support multiple spelling suggestions and retain original search terms

src/Plugin/views/area/FusionSpellcheck.php

@@ -2,9 +2,9 @@
 
 namespace Drupal\search_api_fusion\Plugin\views\area;
 
-use Drupal\Core\Url;
 use Drupal\Core\Link;
 use Drupal\Core\Path\CurrentPathStack;
+use Drupal\Core\Url;
 use Drupal\views\Plugin\views\area\AreaPluginBase;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
@@ -82,45 +82,53 @@ class FusionSpellcheck extends AreaPluginBase {
       return [];
     }
 
-    // If Fusion provided spellcheck suggestions: order those by frequency.
     $suggestions = $response['spellcheck']['suggestions'];
-    $word = NULL;
-    foreach ($suggestions as $word => $data) {
-      if (isset($data['suggestion'])) {
-        usort($suggestions[$word]['suggestion'],
-            function ($suggestion1, $suggestion2): int {
-              return $suggestion1['freq'] <=> $suggestion2['freq'];
-            });
+    $best_suggestions = [];
+    foreach ($suggestions as $delta => &$data) {
+      // Ensure the suggestion array is defined. This skips string elements in
+      // the array that solely contain a search term.
+      if (isset($data['suggestion']) && !empty($data['suggestion'])) {
+        // Order Fusion provided spellcheck suggestions by frequency.
+        usort($data['suggestion'],
+          function ($suggestion1, $suggestion2): int {
+            return $suggestion1['freq'] <=> $suggestion2['freq'];
+          });
+        // The original search term is in the array element previous to the
+        // suggestions.
+        $search_term = $suggestions[$delta - 1];
+        // Extract suggested word with the highest frequency (last array
+        // element). Use the original search term as the array key.
+        $best_suggestions[$search_term] = $data['suggestion'][array_key_last($data['suggestion'])]['word'];
       }
     }
 
-    if (empty($suggestions[$word]['suggestion'])
-      || !is_array($suggestions[$word]['suggestion'])) {
+    if (empty($best_suggestions)) {
       return [];
     }
 
-    // Extract suggestion with highest frequency.
-    end($suggestions[$word]['suggestion']);
-    $best_suggestion = current($suggestions[$word]['suggestion']);
-
+    $link = $this->getSuggestionLink($best_suggestions);
+    if (is_null($link)) {
+      return [];
+    }
     // Return hyperlink "Did you mean: <best spellcheck suggestion> ?".
     return [
       '#theme' => 'search_api_fusion_spellcheck',
       '#label' => $this->t('Did you mean:'),
-      '#link' => $this->getSuggestionLink($best_suggestion['word']),
+      '#link' => $link,
     ];
   }
 
   /**
    * Gets the suggestion link.
    *
-   * @param string $suggestion
-   *   The suggested search query.
+   * @param array $suggestions
+   *   Array of suggested spellcheck words keyed by the original search terms.
    *
-   * @return \Drupal\Core\Link
-   *   The suggestion link.
+   * @return Link|NULL
+   *   The suggestion link or NULL if the query is not set or the suggested
+   *   text matches the original search terms.
    */
-  protected function getSuggestionLink($suggestion) {
+  protected function getSuggestionLink(array $suggestions) {
     if ($this->view->hasUrl()) {
       $path = '/' . $this->view->getPath();
     }
@@ -129,15 +137,38 @@ class FusionSpellcheck extends AreaPluginBase {
     }
 
     $currentQuery = $this->getCurrentQuery();
-
     unset($currentQuery['q']);
+    if (!isset($currentQuery['query'])) {
+      return NULL;
+    }
+
+    // Search and replace the original search terms with the returned suggested
+    // words. This way the original search terms without a spelling suggestion
+    // are preserved.
+    // Use the original search term(s) as a default.
+    $suggested_text = $currentQuery['query'];
+    foreach ($suggestions as $original_term => $suggested_term) {
+      // Replace only full words and not part of a word.
+      $suggested_text = preg_replace(
+        '/\b' . $original_term . '\b/u',
+        $suggested_term,
+        $suggested_text
+      );
+    }
+
+    // Handle the rare possibility of the original search term(s) matching the
+    // suggested text.
+    if ($suggested_text == $currentQuery['query']) {
+      return NULL;
+    }
+
     $url = Url::fromUserInput($path, [
       'query' => [
-        'query' => $suggestion,
-      ] + $currentQuery,
+          'query' => $suggested_text,
+        ] + $currentQuery,
     ]);
 
-    return Link::fromTextAndUrl($suggestion, $url);
+    return Link::fromTextAndUrl($suggested_text, $url);
   }
 
   /**
@@ -146,7 +177,7 @@ class FusionSpellcheck extends AreaPluginBase {
    * @return array
    *   Key value of parameters.
    */
-  protected function getCurrentQuery() {
+  public function getCurrentQuery(): array {
     if (NULL === $this->currentQuery) {
       $this->currentQuery = $this->view->getRequest()->query->all();
     }