email the assignee when a ticket is assigend

csharp/App/Backend/Controller.cs

@@ -2134,6 +2134,31 @@ public class Controller : ControllerBase
             });
         }
 
+        var assigneeChanged = ticket.AssigneeId != existing.AssigneeId
+                           && ticket.AssigneeId.HasValue;
+
+        if (assigneeChanged)
+        {
+            var assignee = Db.GetUserById(ticket.AssigneeId);
+
+            Db.Create(new TicketTimelineEvent
+            {
+                TicketId    = ticket.Id,
+                EventType   = (Int32)TimelineEventType.Assigned,
+                Description = $"Ticket assigned to {assignee?.Name ?? "unknown"}.",
+                ActorType   = (Int32)TimelineActorType.Human,
+                ActorId     = user.Id,
+                CreatedAt   = DateTime.UtcNow
+            });
+
+            if (assignee is not null)
+                _ = Task.Run(async () =>
+                {
+                    try { await assignee.SendTicketAssignedEmail(ticket); }
+                    catch (Exception ex) { Console.WriteLine($"Failed to send ticket assignment email: {ex}"); }
+                });
+        }
+
         return Db.Update(ticket) ? ticket : StatusCode(500, "Update failed.");
     }
 

csharp/App/Backend/DataTypes/Methods/User.cs

@@ -297,5 +297,66 @@ public static class UserMethods
 
         return user.SendEmail(subject, body);
     }
-    
+
+    public static Task SendTicketAssignedEmail(this User user, Ticket ticket)
+    {
+        var ticketLink = $"https://monitor.inesco.energy/tickets/{ticket.Id}";
+        var priority   = (TicketPriority)ticket.Priority;
+        var category   = (TicketCategory)ticket.Category;
+
+        var (subject, body) = (user.Language ?? "en") switch
+        {
+            "de" => (
+                $"inesco Energy – Ticket #{ticket.Id} wurde Ihnen zugewiesen",
+                $"Sehr geehrte/r {user.Name},\n\n" +
+                $"Ein Ticket wurde Ihnen zugewiesen:\n\n" +
+                $"Ticket:    #{ticket.Id}\n" +
+                $"Betreff:   {ticket.Subject}\n" +
+                $"Priorität: {priority}\n" +
+                $"Kategorie: {category}\n\n" +
+                $"Beschreibung:\n{ticket.Description}\n\n" +
+                $"Öffnen Sie das Ticket hier: {ticketLink}\n\n" +
+                "Mit freundlichen Grüssen\ninesco Energy Monitor"
+            ),
+            "fr" => (
+                $"inesco Energy – Le ticket #{ticket.Id} vous a été attribué",
+                $"Cher/Chère {user.Name},\n\n" +
+                $"Un ticket vous a été attribué :\n\n" +
+                $"Ticket :    #{ticket.Id}\n" +
+                $"Objet :     {ticket.Subject}\n" +
+                $"Priorité :  {priority}\n" +
+                $"Catégorie : {category}\n\n" +
+                $"Description :\n{ticket.Description}\n\n" +
+                $"Ouvrir le ticket : {ticketLink}\n\n" +
+                "Cordialement,\ninesco Energy Monitor"
+            ),
+            "it" => (
+                $"inesco Energy – Il ticket #{ticket.Id} le è stato assegnato",
+                $"Gentile {user.Name},\n\n" +
+                $"Le è stato assegnato un ticket:\n\n" +
+                $"Ticket:     #{ticket.Id}\n" +
+                $"Oggetto:    {ticket.Subject}\n" +
+                $"Priorità:   {priority}\n" +
+                $"Categoria:  {category}\n\n" +
+                $"Descrizione:\n{ticket.Description}\n\n" +
+                $"Aprire il ticket: {ticketLink}\n\n" +
+                "Cordiali saluti,\ninesco Energy Monitor"
+            ),
+            _ => (
+                $"inesco Energy – Ticket #{ticket.Id} has been assigned to you",
+                $"Dear {user.Name},\n\n" +
+                $"A ticket has been assigned to you:\n\n" +
+                $"Ticket:   #{ticket.Id}\n" +
+                $"Subject:  {ticket.Subject}\n" +
+                $"Priority: {priority}\n" +
+                $"Category: {category}\n\n" +
+                $"Description:\n{ticket.Description}\n\n" +
+                $"Open the ticket: {ticketLink}\n\n" +
+                "Best regards,\ninesco Energy Monitor"
+            )
+        };
+
+        return user.SendEmail(subject, body);
+    }
+
 }