added function chaining for db query

backend/service/db/dbEvents.go

@@ -77,24 +77,50 @@ func findEventByDayWeekStartEndNameCourse(event model.Event, course string, app
 	return &event, err
 }
 
+func buildIcalQueryForModules(modules []model.FeedCollection) dbx.Expression {
+
+	// build where conditions for each module
+
+	//first check if modules is empty
+	if len(modules) == 0 {
+		return dbx.HashExp{}
+	}
+
+	//second check if modules has only one element
+	if len(modules) == 1 {
+		return dbx.And(
+			dbx.HashExp{"Name": modules[0].Name},
+			dbx.HashExp{"course": modules[0].Course},
+		)
+	}
+
+	//third check if modules has more than one element
+	var wheres []dbx.Expression
+
+	for _, module := range modules {
+		where := dbx.And(
+			dbx.HashExp{"Name": module.Name},
+			dbx.HashExp{"course": module.Course},
+		)
+		wheres = append(wheres, where)
+	}
+
+	// Use dbx.And or dbx.Or to combine the where conditions as needed
+	where := dbx.Or(wheres...)
+
+	return where
+
+}
+
 // GetPlanForModules returns all events for the given modules with the given course
 // used for the ical feed
 func GetPlanForModules(app *pocketbase.PocketBase, modules []model.FeedCollection) model.Events {
 
-	// build query functions with name equals elements in modules for dbx query
-
-	var queryString string
-	for i, module := range modules {
-		if i == 0 {
-			queryString = "Name = '" + module.Name + "' AND course = '" + module.Course + "'"
-		} else {
-			queryString = queryString + " OR Name = '" + module.Name + "' AND course = '" + module.Course + "'"
-		}
-	}
+	var selectedModulesQuery = buildIcalQueryForModules(modules)
 
 	var events model.Events
 	// get all events from event records in the events collection
-	err := app.Dao().DB().Select("*").From("events").Where(dbx.NewExp(queryString)).All(&events)
+	err := app.Dao().DB().Select("*").From("events").Where(selectedModulesQuery).All(&events)
 	if err != nil {
 		print("Error while getting events from database: ", err)
 		return nil