final class MessageFilterExtension: ILMessageFilterExtension {
    var words:[Item] = []
    let stack = CoreDataStack()
    
    func loadItems() {
        let context = stack.persistentContainer.viewContext
        let itemDAO = ItemDAO(managedObjectContext: context)
        let allItems = itemDAO.fetchItmes()
        self.words = allItems.flatMap({ item in
            return item.value != nil ? item : nil
        })
    }
}

extension MessageFilterExtension: ILMessageFilterQueryHandling {
    
    func handle(_ queryRequest: ILMessageFilterQueryRequest, context: ILMessageFilterExtensionContext, completion: @escaping (ILMessageFilterQueryResponse) -> Void) {
     
        let action = self.offlineAction(for: queryRequest)
        let response = ILMessageFilterQueryResponse()
        response.action = action
        completion(response)
    }
    
    private func offlineAction(for queryRequest: ILMessageFilterQueryRequest) -> ILMessageFilterAction {
        guard let messageBody = queryRequest.messageBody?.lowercased() else { return .none }
        
        self.loadItems()
        
        for word in self.words {
            if let value = word.value,
                messageBody.contains(value.lowercased()) {
                return .filter
            }
        }
        return .allow
    }
}