Merge branch '5991-orcid-last-character-may-be-x-and-not-a-number' into '1.4-dev'

Resolve "ORCID last character may be 'X' and not a number"

See merge request fusiondirectory/fd-plugins!611

personal/personal/personal/class_socialHandlers.inc

@@ -141,9 +141,25 @@ class socialHandler_orcid extends socialHandler
 
   function validate ($value)
   {
-    if (!preg_match('/^[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{4}$/', $value)) {
+    if (!preg_match('/^[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{3}[0-9X]$/', $value)) {
       throw new socialHandlerInvalidValueException(_('ORCID account IDs must look like XXXX-XXXX-XXXX-XXXX where X are digits'));
     }
+    if (static::orcidCheckSum($value) != substr($value, -1)) {
+      throw new socialHandlerInvalidValueException(_('Incorrect ORCID value, the checksum does not match'));
+    }
     return $value;
   }
+
+  public static function orcidCheckSum (string $orcid): string
+  {
+    /* Remove hyphens, remove last digit, convert to array */
+    $baseDigits = str_split(str_replace('-', '', substr($orcid, 0, -1)));
+    $sum = 0;
+    foreach ($baseDigits as $baseDigit) {
+      $sum = ($sum + $baseDigit) * 2;
+    }
+    $remainder  = $sum % 11;
+    $result     = (12 - $remainder) % 11;
+    return (($result == 10) ? "X" : (string)$result);
+  }
 }