added edit and delete event functions

internal/storage/storage.go

@@ -119,3 +119,76 @@ func GetEventsForDay(year,month,day int32) ([]*calendar.Event,error) {
 	})
 	return events,err
 }
+
+func EditEvent(originalYear, originalMonth, originalDay, originalStartHour int32, updated EventInput) error {
+	if db == nil {
+		err := fmt.Errorf("badger DB is not initialized")
+		logger.Log.Error(err)
+		return err
+	}
+
+	// Reject changes to key-defining fields
+	if updated.Year != originalYear ||
+		updated.Month != originalMonth ||
+		updated.Day != originalDay ||
+		updated.StartHour != originalStartHour {
+
+		err := fmt.Errorf("editing key-defining fields (year, month, day, startHour) is not allowed; delete and recreate instead")
+		logger.Log.Error(err)
+		return err
+	}
+
+	key := fmt.Appendf(nil, "events/%04d-%02d-%02d/%02d", originalYear, originalMonth, originalDay, originalStartHour)
+
+	event := &calendar.Event{
+		Title:       updated.Title,
+		Description: updated.Description,
+		Year:        originalYear,
+		Month:       originalMonth,
+		Day:         originalDay,
+		StartHour:   originalStartHour,
+		EndHour:     updated.EndHour,
+		Color:       updated.Color,
+	}
+
+	data, err := proto.Marshal(event)
+	if err != nil {
+		err = fmt.Errorf("failed to marshal updated event: %w", err)
+		logger.Log.Error(err)
+		return err
+	}
+
+	err = db.Update(func(txn *badger.Txn) error {
+		return txn.Set(key, data)
+	})
+
+	if err != nil {
+		err = fmt.Errorf("failed to update event in DB: %w", err)
+		logger.Log.Error(err)
+		return err
+	}
+
+	return nil
+}
+
+func DeleteEvent(year, month, day, startHour int32) error {
+	if db == nil {
+		err := fmt.Errorf("badger DB is not initialized")
+		logger.Log.Error(err)
+		return err
+	}
+
+	key := fmt.Appendf(nil, "events/%04d-%02d-%02d/%02d", year, month, day, startHour)
+
+	err := db.Update(func(txn *badger.Txn) error {
+		return txn.Delete(key)
+	})
+	if err != nil {
+		err = fmt.Errorf("failed to delete event from DB: %w", err)
+		logger.Log.Error(err)
+		return err
+	}
+
+	return nil
+}
+