using System;
using System.Collections.Generic;
using System.Collections.Concurrent;
using System.Net;
using System.Net.Sockets;

namespace RoboidControl {

    /// <summary>
    /// A participant is used for communcation between things
    /// </summary>
    public class Participant : RemoteParticipant {
        public byte[] buffer = new byte[1024];
        public ulong publishInterval = 3000; // = 3 seconds

        public string name = "Participant";

        public IPEndPoint endPoint = null;
        public UdpClient udpClient = null;
        public string broadcastIpAddress = "255.255.255.255";

        public readonly ConcurrentQueue<IMessage> messageQueue = new ConcurrentQueue<IMessage>();

        #region Init

        /// <summary>
        /// Create a porticiapnt
        /// </summary>
        public Participant() {
            //senders.Add(this);
        }

        /// <summary>
        /// Create a participant with the give UDP port
        /// </summary>
        /// <param name="port">The port number on which to communicate</param>
        // public Participant(int port) : this() {
        //     this.port = port;
        // }

        /// <summary>
        /// Create a new participant for a site at the given address and port
        /// </summary>
        /// <param name="ipAddress">The ip address of the site server</param>
        /// <param name="port">The port number of the site server</param>
        public Participant(string ipAddress = "0.0.0.0", int port = 7681) : this() {
            this.ipAddress = ipAddress;
            this.port = port;

            this.udpClient = new UdpClient();
            this.udpClient.Client.Bind(new IPEndPoint(IPAddress.Any, port)); // local port
            // this.endPoint = new IPEndPoint(IPAddress.Parse(ipAddress), port); // for sending

            // this.udpClient = new UdpClient(port); // for receiving
            // this.udpClient.Client.Bind(new IPEndPoint(IPAddress.Any, port));
            this.udpClient.BeginReceive(new AsyncCallback(result => ReceiveUDP(result)), null);
        }

        /// <summary>
        /// Create a participant using the given udp client
        /// </summary>
        /// <param name="udpClient">UDP client to use for communication</param>
        /// <param name="port">The port number on which to communicate</param>
        public Participant(UdpClient udpClient, int port) : this() {
            this.udpClient = udpClient;
            this.port = port;
        }

        public List<RemoteParticipant> senders = new List<RemoteParticipant>();

        public RemoteParticipant GetParticipant(string ipAddress, int port) {
            //Console.WriteLine($"Get Participant {ipAddress}:{port}");
            foreach (RemoteParticipant sender in senders) {
                if (sender.ipAddress == ipAddress && sender.port == port)
                    return sender;
            }
            return null;
        }
        public RemoteParticipant AddParticipant(string ipAddress, int port) {
            Console.WriteLine($"New Participant {ipAddress}:{port}");
            RemoteParticipant participant = new RemoteParticipant(ipAddress, port) {
                networkId = (byte)this.senders.Count
            };
            senders.Add(participant);
            return participant;
        }

        protected readonly Dictionary<byte, Func<RemoteParticipant, byte, byte, Thing>> thingMsgProcessors = new Dictionary<byte, Func<RemoteParticipant, byte, byte, Thing>>();

        public delegate Thing ThingConstructor(RemoteParticipant sender, byte networkId, byte thingId);
        public void Register(byte thingType, ThingConstructor constr) {
            thingMsgProcessors[thingType] = new Func<RemoteParticipant, byte, byte, Thing>(constr);
        }

        public void Register<ThingClass>(Thing.Type thingType) where ThingClass : Thing {
            Register<ThingClass>((byte)thingType);
        }

        public void Register<ThingClass>(byte thingType) where ThingClass : Thing {
            thingMsgProcessors[thingType] = (RemoteParticipant sender, byte networkId, byte thingId) =>
                Activator.CreateInstance(typeof(ThingClass), sender, networkId, thingId) as ThingClass;
            Console.WriteLine($"Registering {typeof(ThingClass)} for thing type {thingType}");
        }

        #endregion Init

        #region Update

        protected void ReceiveUDP(IAsyncResult result) {
            if (this.udpClient == null || this.endPoint == null)
                return;

            byte[] data = this.udpClient.EndReceive(result, ref this.endPoint);
            // This does not yet take multi-packet messages into account!
            if (this.endPoint == null)
                return;

            // We can receive our own publish (broadcast) packages. How do we recognize them????
            // It is hard to determine our source port
            string ipAddress = this.endPoint.Address.ToString();
            RemoteParticipant remoteParticipant = GetParticipant(ipAddress, this.endPoint.Port);
            if (remoteParticipant == null)
                remoteParticipant = AddParticipant(ipAddress, this.endPoint.Port);

            ReceiveData(data, remoteParticipant);

            udpClient.BeginReceive(new AsyncCallback(callbackResult => ReceiveUDP(callbackResult)), null);
        }

        protected ulong nextPublishMe = 0;
        public virtual void Update(ulong currentTimeMS = 0) {
            if (currentTimeMS == 0) {
#if UNITY_5_3_OR_NEWER
                currentTimeMS = (ulong)(UnityEngine.Time.time * 1000);
#endif
            }

            if (this.publishInterval > 0 && currentTimeMS > this.nextPublishMe) {
                Publish();
                // Console.WriteLine($"{this.name} Publish ClientMsg {this.networkId}");
                this.nextPublishMe = currentTimeMS + this.publishInterval;
            }

            int n = this.things.Count;
            for (int ix = 0; ix < n; ix++) {
                Thing thing = this.things[ix];
                if (thing != null) {
                    thing.Update(currentTimeMS);
                    BinaryMsg binaryMsg = new(this.networkId, thing);
                    foreach (RemoteParticipant sender in this.senders)
                        this.Send(sender, binaryMsg);
                }
            }
        }

        public virtual void Publish() {
            this.Publish(new ParticipantMsg(this.networkId));
        }

        #endregion Update

        #region Send

        public void SendThingInfo(RemoteParticipant remoteParticipant, Thing thing) {
            Console.WriteLine("Send thing info");
            this.Send(remoteParticipant, new ThingMsg(this.networkId, thing));
            this.Send(remoteParticipant, new NameMsg(this.networkId, thing));
            this.Send(remoteParticipant, new ModelUrlMsg(this.networkId, thing));
            this.Send(remoteParticipant, new BinaryMsg(this.networkId, thing));
        }

        public bool Send(IMessage msg) {
            int bufferSize = msg.Serialize(ref this.buffer);
            if (bufferSize <= 0)
                return true;

            // Console.WriteLine($"msg to {endPoint.Address.ToString()} {endPoint.Port}");
            this.udpClient?.Send(this.buffer, bufferSize, this.endPoint);
            return true;
        }

        public bool Send(RemoteParticipant remoteParticipant, IMessage msg) {
            int bufferSize = msg.Serialize(ref this.buffer);
            if (bufferSize <= 0)
                return true;

            IPEndPoint participantEndpoint = new IPEndPoint(IPAddress.Parse(remoteParticipant.ipAddress), remoteParticipant.port);
            Console.WriteLine($"msg to {participantEndpoint.Address.ToString()} {participantEndpoint.Port}");
            this.udpClient?.Send(this.buffer, bufferSize, participantEndpoint);
            return true;
        }

        public void PublishThingInfo(Thing thing) {
            //Console.WriteLine("Publish thing info");
            this.Publish(new ThingMsg(this.networkId, thing));
            this.Publish(new NameMsg(this.networkId, thing));
            this.Publish(new ModelUrlMsg(this.networkId, thing));
            this.Publish(new BinaryMsg(this.networkId, thing));
        }

        public bool Publish(IMessage msg) {
            int bufferSize = msg.Serialize(ref this.buffer);
            if (bufferSize <= 0)
                return true;

            // Console.WriteLine($"publish to {broadcastIpAddress.ToString()} {this.port}");
            this.udpClient?.Send(this.buffer, bufferSize, this.broadcastIpAddress, this.port);
            return true;
        }

        public bool SendBuffer(int bufferSize) {
            //if (this.ipAddress == null)
            //    return false;

            // UnityEngine.Debug.Log($"Send msg {buffer[0]} to {ipAddress}");
            //this.udpClient.Send(this.buffer, bufferSize, this.ipAddress, this.port);
            this.udpClient?.Send(this.buffer, bufferSize, this.endPoint);
            return true;
        }

        public bool PublishBuffer(int bufferSize) {
            if (this.broadcastIpAddress == null)
                return false;

            this.udpClient?.Send(this.buffer, bufferSize, this.broadcastIpAddress, this.port);
            return true;
        }

        #endregion

        #region Receive

        public void ReceiveData(byte[] data, RemoteParticipant remoteParticipant) {
            byte msgId = data[0];
            if (msgId == 0xFF) {
                // Timeout
                return;
            }

            switch (msgId) {
                case ParticipantMsg.Id: // 0xA0 / 160
                    this.Process(remoteParticipant, new ParticipantMsg(data));
                    break;
                case NetworkIdMsg.Id: // 0xA1 / 161
                    this.Process(remoteParticipant, new NetworkIdMsg(data));
                    break;
                case InvestigateMsg.Id: // 0x81
                    // result = await InvestigateMsg.Receive(dataStream, client, packetSize);
                    break;
                case ThingMsg.id: // 0x80 / 128
                    this.Process(remoteParticipant, new ThingMsg(data));
                    break;
                case NameMsg.Id: // 0x91 / 145
                    this.Process(remoteParticipant, new NameMsg(data));
                    break;
                case ModelUrlMsg.Id: // 0x90 / 144
                    this.Process(remoteParticipant, new ModelUrlMsg(data));
                    break;
                case PoseMsg.Id: // 0x10 / 16
                    this.Process(remoteParticipant, new PoseMsg(data));
                    // result = await PoseMsg.Receive(dataStream, client, packetSize);
                    break;
                case BinaryMsg.Id: // 0xB1 / 177
                    this.Process(remoteParticipant, new BinaryMsg(data));
                    break;
                case TextMsg.Id: // 0xB0 / 176
                    // result = await TextMsg.Receive(dataStream, client, packetSize);
                    break;
                case DestroyMsg.Id: // 0x20 / 32
                    // result = await DestroyMsg.Receive(dataStream, client, packetSize);
                    break;
                default:
                    break;
            }
        }

        #endregion

        #region Process

        protected virtual void Process(RemoteParticipant sender, ParticipantMsg msg) { }

        protected virtual void Process(RemoteParticipant sender, NetworkIdMsg msg) {
            Console.WriteLine($"{this.name} receive network id {this.networkId} {msg.networkId}");
            if (this.networkId != msg.networkId) {
                this.networkId = msg.networkId;
                foreach (Thing thing in this.things) //Thing.GetAllThings())
                    this.SendThingInfo(sender, thing);
            }
        }

        protected virtual void Process(InvestigateMsg msg) { }

        protected virtual void Process(RemoteParticipant sender, ThingMsg msg) {
            Console.WriteLine($"Participant: Process thing [{msg.networkId}/{msg.thingId}]");
        }

        protected virtual void Process(RemoteParticipant sender, NameMsg msg) {
            // Console.WriteLine($"Participant: Process name [{msg.networkId}/{msg.thingId}] {msg.name}");
            Thing thing = sender.Get(msg.networkId, msg.thingId);
            if (thing != null)
                thing.name = msg.name;
        }

        protected virtual void Process(RemoteParticipant sender, ModelUrlMsg msg) {
            //Console.WriteLine($"Participant: Process model [{msg.networkId}/{msg.thingId}] {msg.url}");
            Thing thing = sender.Get(msg.networkId, msg.thingId);
            if (thing != null)
                thing.modelUrl = msg.url;
            Thing thing = sender.Get(msg.networkId, msg.thingId);
            if (thing != null)
                thing.modelUrl = msg.url;
        }

        protected virtual void Process(RemoteParticipant sender, PoseMsg msg) {
            //Console.WriteLine($"Participant: Process pose [{msg.networkId}/{msg.thingId}] {msg.poseType}");
            Thing thing = sender.Get(msg.networkId, msg.thingId);
            if (thing != null) {
                thing.hasPosition = false;
                if ((msg.poseType & PoseMsg.Pose_Position) != 0) {
                    thing.position = msg.position;
                    thing.hasPosition = true;
                }
                if ((msg.poseType & PoseMsg.Pose_Orientation) != 0)
                    thing.orientation = msg.orientation;
                else
                    thing.orientation = null;
                if ((msg.poseType & PoseMsg.Pose_LinearVelocity) != 0)
                    thing.linearVelocity = msg.linearVelocity;
                if ((msg.poseType & PoseMsg.Pose_AngularVelocity) != 0)
                    thing.angularVelocity = msg.angularVelocity;
                
            }
         }

        protected virtual void Process(RemoteParticipant sender, BinaryMsg msg) {
            // Console.WriteLine($"Participant: Process binary [{msg.networkId}/{msg.thingId}]");
            Thing thing = sender.Get(msg.networkId, msg.thingId);
            thing?.ProcessBinary(msg.bytes);
        }

        protected virtual void Process(TextMsg temsgxt) { }

        protected virtual void Process(DestroyMsg msg) { }

        private void ForwardMessage(IMessage msg) {
            foreach (Participant client in senders) {
                if (client == this)
                    continue;
                //UnityEngine.Debug.Log($"---> {client.ipAddress}");
                //IMessage.SendMsg(client, msg);
                msg.Serialize(ref client.buffer);
                client.SendBuffer(client.buffer.Length);
            }
        }

        #endregion
    }
}