RoboidControl-csharp/src/Participants/SiteServer.cs

using System;
using System.Net;
using System.Net.Sockets;
using System.Net.NetworkInformation;

namespace RoboidControl {

    /// <summary>
    /// A site server is a participant which provides a shared simulated environment 
    /// </summary>
    public class SiteServer : ParticipantUDP {

        #region Init

        /// <summary>
        /// Create a new site server
        /// </summary>
        /// <param name="port">The port of which to receive the messages</param>
        public SiteServer(int port = 7681) : base(port) {
            this.name = "Site Server";

            // Determine local IP address
            IPAddress localIpAddress = null;
            IPAddress subnetMask = null;
            using (Socket socket = new(AddressFamily.InterNetwork, SocketType.Dgram, 0)) {
                // Connect to a remote endpoint — we won't actually send anything
                socket.Connect("1.1.1.1", 65530);
                if (socket.LocalEndPoint is IPEndPoint endPoint) {
                    localIpAddress = endPoint.Address;
                    this.ipAddress = localIpAddress.ToString();
                }
            }
            // Find subnet mask
            foreach (NetworkInterface nwInterface in NetworkInterface.GetAllNetworkInterfaces()) {
                if (nwInterface.OperationalStatus != OperationalStatus.Up)
                    continue;

                foreach (UnicastIPAddressInformation unicastAddress in nwInterface.GetIPProperties().UnicastAddresses) {
                    if (unicastAddress.Address.AddressFamily == AddressFamily.InterNetwork && unicastAddress.Address.Equals(localIpAddress)
                    ) {
                        subnetMask = unicastAddress.IPv4Mask;
                    }
                }
            }
            if (localIpAddress != null && subnetMask != null)
                GetBroadcastAddress(localIpAddress, subnetMask);

            Console.Write($"Prepare receive on port {port}");
            this.endPoint = new IPEndPoint(IPAddress.Any, port);
            this.udpClient = new UdpClient(port);
            this.udpClient.BeginReceive(new AsyncCallback(result => ReceiveUDP(result)), null);

        }

        #endregion Init

        /// <summary>
        ///  Close the site
        /// </summary>
        public void Close() {
            this.udpClient?.Close();
        }

        #region Update

        protected override void UpdateMyThings(ulong currentTimeMS) {
            // We don't use foreach to prevent the 'Collection was modified' error
            int n = this.things.Count;
            for (int ix = 0; ix < n; ix++) {
                Thing thing = this.things[ix];

                if (thing == null)
                    continue;

                thing.Update(currentTimeMS, false);

                if (this.isIsolated == false) {
                    // Send to all other participants
                    //foreach (Participant participant in Participant.participants) {
                    for (int participantIx = 0; participantIx < Participant.participants.Count; participantIx++) {
                        Participant participant = Participant.participants[participantIx];
                        if (participant == null || participant == this)
                            continue;

                        // PoseMsg poseMsg = new(thing.owner.networkId, thing);
                        // this.Send(participant, poseMsg);
                        // BinaryMsg binaryMsg = new(thing.owner.networkId, thing);
                        // this.Send(participant, binaryMsg);
                        participant.Send(new PoseMsg(thing.owner.networkId, thing));
                        participant.Send(new BinaryMsg(thing.owner.networkId, thing));
                    }
                }
            }
        }

        #endregion Update

        #region Receive

        protected override void Process(Participant sender, ParticipantMsg msg) {
            base.Process(sender, msg);
            if (msg.networkId != sender.networkId) {
                //Console.WriteLine($"{this.name} received New Participant -> {sender.networkId}");
                // this.Send(sender, new NetworkIdMsg(sender.networkId));
                sender.Send(new NetworkIdMsg(sender.networkId));
                UpdateEvent e = new() {
                    messageId = ParticipantMsg.Id,
                    participant = sender
                };
                this.updateQueue.Enqueue(e);
            }
        }

        protected override void Process(Participant sender, NetworkIdMsg msg) { }

        protected override void Process(Participant sender, ThingMsg msg) {
            Console.WriteLine($"{this.name}: Process thing [{msg.networkId}/{msg.thingId}] {msg.thingType} {msg.parentId} ");

            Thing thing = sender.Get(msg.thingId);
            if (thing == null) {
                switch (msg.thingType) {
                    case (byte)Thing.Type.TouchSensor:
                        new TouchSensor(sender, msg.thingId);
                        break;
                }
            }

            if (thing == null)
                thing = new Thing(sender, msg.thingType, msg.thingId);

            if (msg.parentId != 0) {
                thing.parent = sender.Get(msg.parentId);
                if (thing.parent == null)
                    Console.WriteLine($"Could not find parent [{msg.networkId}/{msg.parentId}]");
            }
            else {
                // Console.Write($"Dropped {thing.id}");
                thing.parent = null;
            }
        }


        #endregion Receive

    }

}