Configurable top facet override of alphabetical sort for limits (#1807)

config/vufind/facets.ini

@@ -256,6 +256,18 @@ translated_facets[] = callnumber-first:CallNumberFirst
 ; These facets will be displayed on the Home Page when FacetList is turned on in
 ; the content setting of the [HomePage] section of searches.ini. If this section
 ; is omitted, the [Advanced] section will be used instead.
+
+; Override the alphabetical sorting for individual facets and display them at the
+; top of the limits on the advanced search page. As an example, this could be used
+; to display the most commonly searched languages above the rest. All following
+; limits display in the natural sorted order.
+;limitOrderOverride[language] = Icelandic::English::Spanish
+;limitOrderOverride[format] = CD::DVD
+
+; Optional delimiter to use in the limitOrderOverride settings above. When enabled,
+; limits must be separated using the same character set here.
+;limitDelimiter = "::"
+
 [HomePage]
 callnumber-first = "Call Number"
 language         = Language

module/VuFind/src/VuFind/Search/Base/Options.php

@@ -982,4 +982,21 @@ abstract class Options implements TranslatorAwareInterface
         $this->autocompleteAutoSubmit = $searchSettings->Autocomplete->auto_submit
             ?? $this->autocompleteAutoSubmit;
     }
+
+    /**
+     * Get advanced search limits that override the natural sorting to
+     * display at the top.
+     *
+     * @param string $limit advanced search limit
+     *
+     * @return array
+     */
+    public function limitOrderOverride($limit)
+    {
+        $facetSettings = $this->configLoader->get($this->getFacetsIni());
+        $limits = $facetSettings->Advanced_Settings->limitOrderOverride ?? null;
+        $delimiter = $facetSettings->Advanced_Settings->limitDelimiter ?? '::';
+        $limitConf = $limits ? $limits->get($limit) : '';
+        return array_map('trim', explode($delimiter, $limitConf));
+    }
 }

themes/bootstrap3/templates/search/advanced/solr.phtml

@@ -16,16 +16,34 @@
               <?php endforeach; ?>
             <?php else: ?>
               <?php
-              // Sort the current facet list alphabetically; we'll use this data
+              // Sort the current facet list alphabetically and filter items to
+              // the top if they appear in the config; we'll use this data
               // along with the foreach below to display facet options in the
               // correct order.
+              $conf = $this->options->limitOrderOverride($field);
               $sorted = [];
+              $filtered = [];
               foreach ($list['list'] as $i => $value) {
                 if (!empty($value['displayText'])) {
-                  $sorted[$i] = $value['displayText'];
+                  if (in_array($value['displayText'], $conf)) {
+                    $filtered[$i] = $value['displayText'];
+                  } else {
+                    $sorted[$i] = $value['displayText'];
+                  }
                 }
               }
               natcasesort($sorted);
+
+              // Order filtered items according to how they appear in the config.
+              $filterKeys = array_flip($conf);
+              uasort($filtered, function ($a, $b) use ($filterKeys) {
+                return $filterKeys[$a] <=> $filterKeys[$b];
+              });
+
+              // Combine filtered and sorted arrays so that the items in the config
+              // appear in order at the top and all other items appear afterwards
+              // sorted by natcasesort.
+              $sorted = $filtered + $sorted;
               ?>
               <?php foreach ($sorted as $i => $display): ?>
                 <?php $value = $list['list'][$i]; ?>