examples/tv-casting-app/darwin/TvCasting/TvCasting/MCMediaPlaybackSubscribeToCurrentStateExampleViewModel.swift

/**
 *
 *    Copyright (c) 2020-2024 Project CHIP Authors
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */


import Foundation
import os.log

class MCMediaPlaybackSubscribeToCurrentStateExampleViewModel: ObservableObject {
    let Log = Logger(subsystem: "com.matter.casting",
                     category: "MCMediaPlaybackSubscribeToCurrentStateExampleViewModel")
    
    @Published var status: String?;

    // VendorId of the MCEndpoint on the MCCastingPlayer that the MCCastingApp desires to interact with after connection
    let sampleEndpointVid: Int = 65521

    func subscribe(castingPlayer: MCCastingPlayer)
    {
        // select the MCEndpoint on the MCCastingPlayer to invoke the command on
        if let endpoint: MCEndpoint = castingPlayer.endpoints().filter({ $0.vendorId().intValue == sampleEndpointVid}).first
        {
            // validate that the selected endpoint supports the MediaPlayback cluster
            if(!endpoint.hasCluster(MCEndpointClusterTypeMediaPlayback))
            {
                self.Log.error("No MediaPlayback cluster supporting endpoint found")
                DispatchQueue.main.async
                {
                    self.status = "No MediaPlayback cluster supporting endpoint found"
                }
                return
            }
            
            // get MediaPlayback cluster from the endpoint
            let mediaPlaybackCluster: MCMediaPlaybackCluster = endpoint.cluster(for: MCEndpointClusterTypeMediaPlayback) as! MCMediaPlaybackCluster

            // get the currentStateAttribute from the mediaPlaybackCluster
            let currentStateAttribute: MCMediaPlaybackClusterCurrentStateAttribute? = mediaPlaybackCluster.currentStateAttribute()
            if(currentStateAttribute == nil)
            {
                self.Log.error("CurrentState attribute not supported on cluster")
                DispatchQueue.main.async
                {
                    self.status = "CurrentState attribute not supported on cluster"
                }
                return
            }
                
                    
            // call read on currentStateAttribute and pass in a completion block
            currentStateAttribute!.subscribe(nil, completion: { context, before, after, err in
                let dateFormatter = DateFormatter()
                dateFormatter.dateFormat = "HH:mm:ss"
                let currentTime = dateFormatter.string(from: Date())
                DispatchQueue.main.async
                {
                    if(err != nil)
                    {
                        self.Log.error("Error when reading CurrentState value \(String(describing: err)) at \(currentTime)")
                        self.status = "Error when reading CurrentState value \(String(describing: err)) at \(currentTime)"
                        return
                    }
                    if(before != nil)
                    {
                        self.Log.info("Read CurrentState value: \(String(describing: after)) Before: \(String(describing: before)) at \(currentTime)")
                        self.status = "Read CurrentState value: \(String(describing: after)) Before: \(String(describing: before)) at \(currentTime)"
                    }
                    else
                    {
                        self.Log.info("Read CurrentState value: \(String(describing: after)) at \(currentTime)")
                        self.status = "Read CurrentState value: \(String(describing: after)) at \(currentTime)"
                    }
                }
            }, minInterval: 0, maxInterval: 1)
        }
        else
        {
            self.Log.error("No endpoint matching the example VID found")
            DispatchQueue.main.async
            {
                self.status = "No endpoint matching the example VID found"
            }
        }
    }
}