Swift Tutorial: SharePlay and GroupActivities API Example

//
//  ViewController.swift
//  SharePlay Demo
//
//  Created by Kais K. on 02/14/2022.
//

import UIKit
import GroupActivities // Step 1

// This is your custom GroupActivity, this could be in its own file if needed or part of this ViewController
struct ShowAlertSharePlayActivity: GroupActivity {
    var metadata: GroupActivityMetadata {
        var metadata = GroupActivityMetadata()
        metadata.title = NSLocalizedString("Activity Title", comment: "") // The title is visible to the user
        metadata.type = .generic // This is important to set as generic to define a custom activity
        return metadata
    }
}

class ViewController: UIViewController {
    
    var groupSession: GroupSession<ShowAlertSharePlayActivity>? //Group Session of activty type 
    var messenger: GroupSessionMessenger? // The Messenger of the session to send/receive messages between devices
    
    override func viewDidLoad() {
        super.viewDidLoad()
        title = "Show Alert Example"
        
        // On viewDidLoad we need to configure the session
        Task {
            for await session in ShowAlertSharePlayActivity.sessions(){
                configureGroupSession(session) // see implementation below
            }
        }
        
    }
    
    // Link this action to a button on your app to activate the SharePlay activity after the FaceTime call has started and you launched the app
    @IBAction func activateGroupActivity(_ sender: Any) {
        ShowAlertSharePlayActivity().activate()
    }
    
    // Link this action to a button to trigger an alert on their side
    @IBAction func showAlertToOtherUser(_ sender: UIBarButtonItem) {
        if let messenger = messenger {
            Task {
                do {
                    try await messenger.send("Your text here") // or this could be a custom define struct that can be sent to the other device to process. See references below for more details.
                } catch {
                    print("error")
                }
            }
        }
    }
    
    // Func to configure the group session and create a task to wait/listen for any messages that could come via SharePlay
    func configureGroupSession(_ groupSession: GroupSession<ShowAlertSharePlayActivity>) {
        self.groupSession = groupSession
        let messenger = GroupSessionMessenger(session: groupSession)
        self.messenger = messenger
        
        // wait and listen for any messages that could come via SharePlay and handle it
        Task.detached { [weak self] in
            for await (message, _) in messenger.messages(of: String.self) {
                await self?.handle(message) // custom func to handle the received message. See below.
            }
        }
        groupSession.join() // join the session if available
    }
    
    // Func to handle the received message, the param is String, but this also could be a custom struct. See references below.
    func handle(_ message: String) {
        showAlertFromFaceTime()
    }
    
    // Func to be triggered when message received via SharePlay
    func showAlertFromFaceTime() {
        let alert = UIAlertController(title: "Hey", message: "This alert was sent via SharePlay!", preferredStyle: .alert)
        let cancelAction = UIAlertAction(title: "Dismiss", style: .cancel)
        alert.addAction(cancelAction)
        present(alert, animated: true)
    }
    
}