Add remove endpoint

WebApp/Endpoints/EventRegistrationEndpoints.cs

@@ -104,6 +104,31 @@ namespace WebApp.Endpoints
                 });
             });
 
+            // POST /api/events/remove/{id}/{userId}
+            group.MapPost("/remove/{id}/{userId}",
+                async (int id, int userId, ApplicationDbContext dbContext, HttpContext httpContext, GeneralUseHelpers guhf) =>
+            {
+                Event? Eve = await dbContext.Events.FindAsync(id);
+                if (Eve is null)
+                    return Results.Json(new { success = false, error_msg = "Event not found." });
+
+                Token? token = await guhf.GetTokenFromHTTPContext(httpContext);
+                Organisation? org = await guhf.GetOrganisationFromToken(token);
+                if (org is null || org.OrganisationId != Eve.OrganisationId)
+                    return Results.Json(new { success = false, error_msg = "Unauthorized." });
+
+                EventRegistration? registration = await dbContext.EventRegistrations
+                    .FirstOrDefaultAsync(er => er.UserId == userId && er.EventId == id);
+
+                if (registration is null)
+                    return Results.Json(new { success = false, error_msg = "Registration not found." });
+
+                dbContext.EventRegistrations.Remove(registration);
+                await dbContext.SaveChangesAsync();
+
+                return Results.Json(new { success = true });
+            });
+
             return group;
         }
     }