IntentHandler extension for handling SiriKit requests

IntentHandler.swift

import Intents

class IntentHandler: INExtension {
    
    override func handler(for intent: INIntent) -> Any {
        // This is the default implementation.  If you want different objects to handle different intents,
        // you can override this and return the handler you want for that particular intent.
        if intent is OrderPizzaIntent {
            return OrderPizzaIntentHandler()
        }
        
        return self
    }
    
}

OrderPizzaIntentHandler.swift

import Foundation
import Intents

class OrderPizzaIntentHandler: NSObject, OrderPizzaIntentHandling {
    func confirm(intent: OrderPizzaIntent, completion: @escaping (OrderPizzaIntentResponse) -> Void) {
        completion(OrderPizzaIntentResponse(code: .ready, userActivity: nil))
    }

    func handle(intent: OrderPizzaIntent, completion: @escaping (OrderPizzaIntentResponse) -> Void) {
        guard intent.topping != nil else {
            completion(OrderPizzaIntentResponse(code: .failure, userActivity: nil))
            return
        }

        let amount = INCurrencyAmount(amount: NSDecimalNumber(decimal: 23.14), currencyCode: "CAD")
        completion(.success(total: amount))
    }

    func resolveTopping(for intent: OrderPizzaIntent, with completion: @escaping (OrderPizzaToppingResolutionResult) -> Void) {
        guard let topping = intent.topping, !topping.isEmpty else {
            completion(.needsValue())
            return
        }

        guard topping.lowercased() == "pepperoni" else {
            completion(.unsupported(forReason: .ingrediantNotAvailable))
            return
        }

        completion(.success(with: topping))
    }
}