A protocol based solution to capturing analytics in Swift 3

AnalyticsNotificationManager.swift

//
//  AnalyticsNotificationSubscriber.swift
//  DropShift
//
//  Created by Drew Beaupre on 2016-10-03.
//  Copyright © 2016 drew.beaupre. All rights reserved.
//

import Foundation



class AnalyticsNotificationManager: NSObject{
    
    
    var eventSubscribers = [EventType: SubscribableEvent.Type]()

    override init() {

        super.init()
        
        addEventSubscriber(subscriber: EventType.SurveyAnswer.self)
        addEventSubscriber(subscriber: EventType.GameStarted.self)
        addEventSubscriber(subscriber: EventType.GameEnded.self)
        addEventSubscriber(subscriber: EventType.GameReset.self)
    }
    
    private func addEventSubscriber(subscriber: SubscribableEvent.Type){
        
        eventSubscribers[subscriber.eventType] = subscriber
        
        NotificationCenter.default.addObserver(self, selector: #selector(AnalyticsNotificationManager.eventNofication(notification:)) , name: subscriber.eventType.notificationName, object: nil)

    }
    
    func eventNofication(notification: Notification){
        
        guard
            let eventType = EventType(notificationName: notification.name),
            let eventSubscriber = eventSubscribers[eventType],
            let eventProperties = notification.userInfo
            else{
                return
        }
        
        eventSubscriber.handleEvent(eventType: eventType, eventProperties: eventProperties)
    }
    
}

EventType+GameStarted.swift

//
//  EventType+GameStarted.swift
//  DropShift
//
//  Created by Drew Beaupre on 2016-10-03.
//  Copyright © 2016 drew.beaupre. All rights reserved.
//

import Foundation


extension EventType{
    
    struct GameStarted: PublishableEvent, SubscribableEvent{
        
        //MARK PropertyNames
        private enum FieldNames: String{
            case opponentType
        }
        
        //MARK Properties
    
        private(set) var opponentType: PlayerType
        
        //MARK:- PublishableEvent
        
        var eventProperties: [String: Any]? {
            return [
                FieldNames.opponentType.rawValue: opponentType.description
            ]
        }

        //MARK:- SubscribableEvent

        static var eventType: EventType{
            return .gameStarted
        }
    }
    
}

EventType+SurveyAnswer.swift

//
//  EventType+SurveyAnswer.swift
//  DropShift
//
//  Created by Drew Beaupre on 2016-10-18.
//  Copyright © 2016 drew.beaupre. All rights reserved.
//

import Foundation

extension EventType{
    
    struct SurveyAnswer: PublishableEvent, SubscribableEvent{
        
        //MARK PropertyNames
        private enum FieldNames: String{
            case question, answer
        }
        
        //MARK Properties
        
        private(set) var questionText: String
        private(set) var answerValue: String
        
        //MARK:- PublishableEvent
        
        var eventProperties: [String: Any]? {
            return [
                FieldNames.question.rawValue: questionText,
                FieldNames.answer.rawValue: answerValue
            ]
        }
        
        //MARK:- SubscribableEvent
        
        static var eventType: EventType{
            return .surveyAnswer
        }
    }
    
}

EventType.swift

//
//  EventType.swift
//  DropShift
//
//  Created by Drew Beaupre on 2016-10-03.
//  Copyright © 2016 drew.beaupre. All rights reserved.
//

import Foundation

enum EventType: String{
    
    case gameStarted = "Game Started"
    case gameEnded = "Game Ended"
    case gameReset = "Game Reset"
    case surveyAnswer = "Survey Answer"
        
    init?(notificationName: Notification.Name){
        self.init(rawValue: notificationName.rawValue)
    }
}

extension EventType{
    
    var notificationName: NSNotification.Name{
        return NSNotification.Name(rawValue: self.rawValue)
    }
}

extension EventType{
    var segmentName: String{
        return self.rawValue
    }
    
    var gameAnalyticsName: String{
        return self.rawValue.lowercased().replacingOccurrences(of: " ", with: ":")
    }
}

PublishableEvent.swift

//
//  PublishableEvent.swift
//  DropShift
//
//  Created by Drew Beaupre on 2016-10-03.
//  Copyright © 2016 drew.beaupre. All rights reserved.
//

import Foundation

protocol PublishableEvent{
    
    var eventType: EventType {get}
    
    var eventProperties: [String: Any]? { get }
}

extension PublishableEvent{
    
    func publish(){
        
        let userInfo = self.eventProperties
        
        NotificationCenter.default.post(name: eventType.notificationName, object: nil, userInfo: userInfo)
    }
}

extension PublishableEvent where Self: SubscribableEvent{
    
    var eventProperties: [String: Any]? {
        return [String: Any]()
    }
    
    var eventType: EventType{
        return Self.eventType
    }

}

SomeViewController.swift

class GameViewController: UIViewController {
//...lots of other stuff....
  func gameStarted(opponentType: PlayerType) {
    
        //publish the analytics
        EventType.GameStarted(opponentType: opponentPlayerType).publish()
    }
}

SubscribableEvent.swift

//
//  SubscribableEvent.swift
//  DropShift
//
//  Created by Drew Beaupre on 2016-10-03.
//  Copyright © 2016 drew.beaupre. All rights reserved.
//

import Foundation
import Analytics

protocol SubscribableEvent{

    static var eventType: EventType {get}
    
//    static func handleEvent(event: eventType: EventType, eventProperties: [AnyHashable: Any]) -> Void
    
//    static func event(fromNotification notification: Notification) -> PublishableEvent?
}

extension SubscribableEvent{
    
    static func handleEvent(eventType: EventType, eventProperties: [AnyHashable: Any]) -> Void{
        
        var segmentProperties = [String: Any]()
        
        eventProperties.forEach{
            print("EventProperty: \($0.key), \($0.value)")
            guard let keyString = $0.key as? String else{
                print("Could not convert \($0.key) to string.")
                return
            }
            segmentProperties[keyString] = $0.value
        }
        
        SEGAnalytics.shared().track(eventType.segmentName, properties: segmentProperties)
    }
}