debug: add comprehensive logging to membership linking feature

- Added detailed error logging to link_membership_user processor
- Added error handling for database operations in processor
- Added comprehensive logging to linkSecondaryUserToMembership function
- Logs now show: CSRF validation, database operations, link creation, permission grants
- Improved error messages for debugging

src/config/functions.php

@@ -2924,17 +2924,25 @@ function linkSecondaryUserToMembership($primary_user_id, $secondary_user_id, $re
     $conn = openDatabaseConnection();
     
     if ($conn === null) {
+        error_log("linkSecondaryUserToMembership: Database connection failed");
         return ['success' => false, 'message' => 'Database connection failed'];
     }
 
+    error_log("linkSecondaryUserToMembership: primary=$primary_user_id, secondary=$secondary_user_id, relationship=$relationship");
+
     // Validation: primary and secondary user IDs must be different
     if ($primary_user_id === $secondary_user_id) {
+        error_log("linkSecondaryUserToMembership: Cannot link user to themselves");
         return ['success' => false, 'message' => 'Cannot link user to themselves'];
     }
 
     // Validation: primary user must have active membership
-    if (!getUserMemberStatus($primary_user_id)) {
+    $memberStatus = getUserMemberStatus($primary_user_id);
+    error_log("linkSecondaryUserToMembership: Primary user member status = " . ($memberStatus ? 'true' : 'false'));
+    
+    if (!$memberStatus) {
         $conn->close();
+        error_log("linkSecondaryUserToMembership: Primary user does not have active membership");
         return ['success' => false, 'message' => 'Primary user does not have active membership'];
     }
 
@@ -2947,6 +2955,7 @@ function linkSecondaryUserToMembership($primary_user_id, $secondary_user_id, $re
 
     if ($userResult->num_rows === 0) {
         $conn->close();
+        error_log("linkSecondaryUserToMembership: Secondary user does not exist");
         return ['success' => false, 'message' => 'Secondary user does not exist'];
     }
 
@@ -2959,12 +2968,14 @@ function linkSecondaryUserToMembership($primary_user_id, $secondary_user_id, $re
 
     if ($existingResult->num_rows > 0) {
         $conn->close();
+        error_log("linkSecondaryUserToMembership: Users are already linked");
         return ['success' => false, 'message' => 'Users are already linked'];
     }
 
     try {
         // Start transaction
         $conn->begin_transaction();
+        error_log("linkSecondaryUserToMembership: Starting transaction");
 
         // Insert link
         $insertLink = $conn->prepare("
@@ -2972,8 +2983,13 @@ function linkSecondaryUserToMembership($primary_user_id, $secondary_user_id, $re
             VALUES (?, ?, ?, NOW(), NOW())
         ");
         $insertLink->bind_param("iis", $primary_user_id, $secondary_user_id, $relationship);
-        $insertLink->execute();
+        
+        if (!$insertLink->execute()) {
+            throw new Exception("Failed to insert link: " . $insertLink->error);
+        }
+        
         $linkId = $conn->insert_id;
+        error_log("linkSecondaryUserToMembership: Link created with ID = $linkId");
         $insertLink->close();
 
         // Grant default permissions to secondary user
@@ -2991,17 +3007,24 @@ function linkSecondaryUserToMembership($primary_user_id, $secondary_user_id, $re
                 VALUES (?, ?, NOW())
             ");
             $insertPerm->bind_param("is", $linkId, $permission);
-            $insertPerm->execute();
+            
+            if (!$insertPerm->execute()) {
+                throw new Exception("Failed to insert permission: " . $insertPerm->error);
+            }
+            
+            error_log("linkSecondaryUserToMembership: Permission '$permission' granted");
             $insertPerm->close();
         }
 
         // Commit transaction
         $conn->commit();
+        error_log("linkSecondaryUserToMembership: Transaction committed successfully");
         $conn->close();
 
         return ['success' => true, 'message' => 'User successfully linked to membership', 'link_id' => $linkId];
 
     } catch (Exception $e) {
+        error_log("linkSecondaryUserToMembership: Exception - " . $e->getMessage());
         $conn->rollback();
         $conn->close();
         return ['success' => false, 'message' => 'Failed to create link: ' . $e->getMessage()];
@@ -3157,3 +3180,4 @@ function unlinkSecondaryUser($link_id, $primary_user_id)
         return ['success' => false, 'message' => 'Failed to remove link: ' . $e->getMessage()];
     }
 }
+