MDL-54910 mod_data: Open dates should be before close dates

mod/data/lang/en/data.php

@@ -50,6 +50,7 @@
 
 Only the tags that are in the "Available tags" list may be used for the current template.';
 $string['availabletodate'] = 'Available to';
+$string['availabletodatevalidation'] = 'The available to date cannot be before the available from date.';
 $string['blank'] = 'Blank';
 $string['buttons'] = 'Actions';
 $string['bynameondate'] = 'by {$a->name} - {$a->date}';
@@ -368,4 +369,5 @@
 $string['usestandard_help'] = 'To use a preset available to the whole site, select it from the list. (If you have added a preset to the list using the save as preset feature then you have the option of deleting it.)';
 $string['viewfromdate'] = 'Read only from';
 $string['viewtodate'] = 'Read only to';
+$string['viewtodatevalidation'] = 'The read only to date cannot be before the read only from date.';
 $string['wrongdataid'] = 'Wrong data id provided';

mod/data/mod_form.php

@@ -81,6 +81,29 @@ function definition() {
         $this->add_action_buttons();
     }
 
+    /**
+     * Enforce validation rules here
+     *
+     * @param array $data array of ("fieldname"=>value) of submitted data
+     * @param array $files array of uploaded files "element_name"=>tmp_file_path
+     * @return array
+     **/
+    public function validation($data, $files) {
+        $errors = parent::validation($data, $files);
+
+        // Check open and close times are consistent.
+        if ($data['timeavailablefrom'] && $data['timeavailableto'] &&
+                $data['timeavailableto'] < $data['timeavailablefrom']) {
+            $errors['timeavailableto'] = get_string('availabletodatevalidation', 'data');
+        }
+        if ($data['timeviewfrom'] && $data['timeviewto'] &&
+                $data['timeviewto'] < $data['timeviewfrom']) {
+            $errors['timeviewto'] = get_string('viewtodatevalidation', 'data');
+        }
+
+        return $errors;
+    }
+
     function data_preprocessing(&$default_values){
         parent::data_preprocessing($default_values);
     }