Update "Custom field is used" message

app/bundles/CoreBundle/Translations/en_US/flashes.ini

@@ -11,8 +11,8 @@ mautic.core.notice.batch_deleted="%count% items deleted"
 mautic.core.notice.created="<a href='%url%' data-toggle='ajax' data-menu-link='%menu_link%'><strong>%name%</strong></a> has been created!"
 mautic.core.notice.deleted="<strong>%name%</strong> has been deleted!"
 mautic.core.notice.updated="<a href='%url%' data-toggle='ajax' data-menu-link='%menu_link%'><strong>%name%</strong></a> has been updated!"
-mautic.core.notice.used.field="Field %name% (#%id%) is used and cannot be deleted."
-mautic.core.notice.used.fields="Some fields are used and cannot be deleted."
+mautic.core.notice.used.field="Field "%name%" (#%id%) cannot be deleted because it's used in the following Segment(s): %segments%."
+mautic.core.notice.used.fields="Field(s) "%fields%" cannot be deleted because they are used in the following Segment(s): %segments%."
 mautic.core.language.helper.error.fetching.package="An error occurred while downloading the language package."
 mautic.core.language.helper.error.follow.redirects="Whoops, either safe_mode or open_basedir is turned on. Download the language from <a href='%url%'>here</a>. Unzip and upload it to the /translations directory."
 mautic.core.language.helper.invalid.language="Requested language '%language%' does not exist among the available Mautic languages. The language was reset to the default one."

app/bundles/LeadBundle/Controller/FieldController.php

@@ -415,13 +415,19 @@ public function deleteAction($objectId)
                 return $this->accessDenied();
             }
 
-            if ($model->isUsedField($field)) {
+            $segments = [];
+            foreach ($model->getFieldSegments($field) as $segment) {
+                $segments[] = sprintf('"%s" (%d)', $segment->getName(), $segment->getId());
+            }
+
+            if (count($segments)) {
                 $flashMessage = [
                     'type'    => 'error',
                     'msg'     => 'mautic.core.notice.used.field',
                     'msgVars' => [
-                        '%name%' => $field->getLabel(),
-                        '%id%'   => $objectId,
+                        '%name%'     => $field->getLabel(),
+                        '%id%'       => $objectId,
+                        '%segments%' => implode(', ', $segments),
                     ],
                 ];
             } else {
@@ -497,16 +503,34 @@ public function batchDeleteAction()
             // Delete everything we are able to
             if (!empty($deleteIds)) {
                 $filteredDeleteIds = $model->filterUsedFieldIds($deleteIds);
+                $usedFieldIds      = array_diff($deleteIds, $filteredDeleteIds);
+                $segments          = [];
+                $usedFieldsNames   = [];
+
+                if ($usedFieldIds) {
+                    // Iterating through all used fileds to get segments they are used in
+                    foreach ($usedFieldIds as $usedFieldId) {
+                        $fieldEntity = $model->getEntity($usedFieldId);
+                        foreach ($model->getFieldSegments($fieldEntity) as $segment) {
+                            $segments[$segment->getId()] = sprintf('"%s" (%d)', $segment->getName(), $segment->getId());
+                            $usedFieldsNames[]           = sprintf('"%s"', $fieldEntity->getName());
+                        }
+                    }
+                }
 
                 if ($filteredDeleteIds !== $deleteIds) {
                     $flashes[] = [
                         'type'    => 'error',
                         'msg'     => 'mautic.core.notice.used.fields',
+                        'msgVars' => [
+                            '%segments%' => implode(', ', $segments),
+                            '%fields%'   => implode(', ', array_unique($usedFieldsNames)),
+                        ],
                     ];
                 }
 
                 if (count($filteredDeleteIds)) {
-                    $entities = $model->deleteEntities($deleteIds);
+                    $entities = $model->deleteEntities($filteredDeleteIds);
 
                     $flashes[] = [
                         'type'    => 'notice',

app/bundles/LeadBundle/Model/FieldModel.php

@@ -602,6 +602,18 @@ public function isUsedField(LeadField $field)
         return $this->leadListModel->isFieldUsed($field);
     }
 
+    /**
+     * Returns list of all segments that use $field.
+     *
+     * @param LeadField $field
+     *
+     * @return \Doctrine\ORM\Tools\Pagination\Paginator
+     */
+    public function getFieldSegments(LeadField $field)
+    {
+        return $this->leadListModel->getFieldSegments($field);
+    }
+
     /**
      * Filter used field ids.
      *

app/bundles/LeadBundle/Model/ListModel.php

@@ -1722,6 +1722,13 @@ public function getSegmentContactsLineChartData($unit, \DateTime $dateFrom, \Dat
      * @return bool
      */
     public function isFieldUsed(LeadField $field)
+    {
+        $segments = $this->getFieldSegments($field);
+
+        return 0 < $segments->count();
+    }
+
+    public function getFieldSegments(LeadField $field)
     {
         $alias       = $field->getAlias();
         $aliasLength = mb_strlen($alias);
@@ -1733,6 +1740,6 @@ public function isFieldUsed(LeadField $field)
             ],
         ];
 
-        return $this->getEntities(['filter' => $filter])->count() !== 0;
+        return $this->getEntities(['filter' => $filter]);
     }
 }