Add more prerequisite information if exists when loading an item

See BT#5776

main/inc/ajax/lp.ajax.php

@@ -291,10 +291,8 @@ switch ($action) {
         $lpItemId = isset($_GET['lp_item']) ? intval($_GET['lp_item']) : 0;
         if ($lp) {
             $position = $lp->isFirstOrLastItem($lpItemId);
+            echo json_encode($position);
         }
-
-        echo json_encode($position);
-
         break;
     case 'get_parent_names':
         $newItemId = isset($_GET['new_item']) ? intval($_GET['new_item']) : 0;
@@ -325,9 +323,9 @@ switch ($action) {
             echo '1';
         } else {
             if (!empty($lp->error)) {
-                echo $lp->error;
+                echo addslashes($lp->error);
             } else {
-                echo get_lang('LearnpathPrereqNotCompleted');
+                echo addslashes(get_lang('LearnpathPrereqNotCompleted'));
             }
         }
         $lp->error = '';

main/lp/blank.php

@@ -23,28 +23,21 @@ $message = '';
 if (isset($_GET['error'])) {
     switch ($_GET['error']) {
         case 'document_deleted':
-            $message = Display::return_message(
-                get_lang('DocumentHasBeenDeleted'),
-                'error'
-            );
+            $message = Display::return_message(get_lang('DocumentHasBeenDeleted'), 'error');
             break;
         case 'prerequisites':
-            $message = Display::return_message(
-                get_lang('LearnpathPrereqNotCompleted'),
-                'warning'
-            );
+            $prerequisiteMessage = isset($_GET['prerequisite_message']) ? $_GET['prerequisite_message'] : '';
+            $message = Display::return_message(get_lang('LearnpathPrereqNotCompleted'), 'warning');
+            if (!empty($prerequisiteMessage)) {
+                $message = Display::return_message(Security::remove_XSS($prerequisiteMessage), 'warning');
+            }
+
             break;
         case 'document_not_found':
-            $message = Display::return_message(
-                get_lang('FileNotFound'),
-                'warning'
-            );
+            $message = Display::return_message(get_lang('FileNotFound'), 'warning');
             break;
         case 'reached_one_attempt':
-            $message = Display::return_message(
-                get_lang('ReachedOneAttempt'),
-                'warning'
-            );
+            $message = Display::return_message(get_lang('ReachedOneAttempt'), 'warning');
             break;
         case 'x_frames_options':
             $src = Session::read('x_frame_source');

main/lp/lp_content.php

@@ -27,8 +27,8 @@ if (empty($lp_controller_touched)) {
 /** @var learnpath $learnPath */
 $learnPath = Session::read('oLP');
 $learnPath->error = '';
-$lp_type = $learnPath->get_type();
-$lp_item_id = $learnPath->get_current_item_id();
+$lpType = $learnPath->get_type();
+$lpItemId = $learnPath->get_current_item_id();
 
 /**
  * Get a link to the corresponding document.
@@ -36,15 +36,15 @@ $lp_item_id = $learnPath->get_current_item_id();
 $src = '';
 if ($debug > 0) {
     error_log('New lp - In lp_content.php - Looking for file url');
-    error_log("lp_type $lp_type");
-    error_log("lp_item_id $lp_item_id");
+    error_log("lp_type $lpType");
+    error_log("lp_item_id $lpItemId");
 }
 
 $list = $learnPath->get_toc();
 $dir = false;
 
 foreach ($list as $toc) {
-    if ($toc['id'] == $lp_item_id && $toc['type'] == 'dir') {
+    if ($toc['id'] == $lpItemId && $toc['type'] == 'dir') {
         $dir = true;
     }
 }
@@ -52,38 +52,38 @@ foreach ($list as $toc) {
 if ($dir) {
     $src = 'blank.php';
 } else {
-    switch ($lp_type) {
+    switch ($lpType) {
         case 1:
             $learnPath->stop_previous_item();
-            $prereq_check = $learnPath->prerequisites_match($lp_item_id);
+            $prerequisiteCheck = $learnPath->prerequisites_match($lpItemId);
 
-            if ($prereq_check === true) {
-                $src = $learnPath->get_link('http', $lp_item_id);
+            if ($prerequisiteCheck === true) {
+                $src = $learnPath->get_link('http', $lpItemId);
                 $learnPath->start_current_item(); // starts time counter manually if asset
                 $src = $learnPath->fixBlockedLinks($src);
 
                 break;
             }
 
-            $src = 'blank.php?error=prerequisites';
+            $src = 'blank.php?error=prerequisites&prerequisite_message='.$learnPath->error;
             break;
         case 2:
             $learnPath->stop_previous_item();
-            $prereq_check = $learnPath->prerequisites_match($lp_item_id);
+            $prerequisiteCheck = $learnPath->prerequisites_match($lpItemId);
 
-            if ($prereq_check === true) {
-                $src = $learnPath->get_link('http', $lp_item_id);
+            if ($prerequisiteCheck === true) {
+                $src = $learnPath->get_link('http', $lpItemId);
                 $learnPath->start_current_item(); // starts time counter manually if asset
             } else {
-                $src = 'blank.php?error=prerequisites';
+                $src = 'blank.php?error=prerequisites&prerequisite_message='.$learnPath->error;
             }
             break;
         case 3:
             // save old if asset
             $learnPath->stop_previous_item(); // save status manually if asset
-            $prereq_check = $learnPath->prerequisites_match($lp_item_id);
-            if ($prereq_check === true) {
-                $src = $learnPath->get_link('http', $lp_item_id);
+            $prerequisiteCheck = $learnPath->prerequisites_match($lpItemId);
+            if ($prerequisiteCheck === true) {
+                $src = $learnPath->get_link('http', $lpItemId);
                 $learnPath->start_current_item(); // starts time counter manually if asset
             } else {
                 $src = 'blank.php';
@@ -97,7 +97,7 @@ if ($dir) {
 if ($debug > 0) {
     error_log('New lp - In lp_content.php - File url is '.$src);
 }
-$learnPath->set_previous_item($lp_item_id);
+$learnPath->set_previous_item($lpItemId);
 
 if (api_is_in_gradebook()) {
     $interbreadcrumb[] = [