source: branches/thasling/DistributedGA/DistributedGA.Core/Implementation/WcfPeerListManager.cs @ 13887

using System;
using System.Collections.Generic;
using System.Linq;
using System.ServiceModel;
using DistributedGA.Core.Domain;
using DistributedGA.Core.Interface;
using System.Timers;

namespace DistributedGA.Core.Implementation
{
    public class WcfPeerListManager : IPeerListManager
    {
        private string serverString = null;

        private IContactService client = null;

        private IContactService heartbeatClient = null;

        private PeerInfo myself = null;

        private Timer timer = null; //sends heartbeat to contact-server

        public void Init(PeerInfo source, string contactServerUrl)
        {
            serverString = contactServerUrl;
            client = CreateClient();
            heartbeatClient = CreateClient();
            myself = source;
            client.RegisterPeer(source);
            timer = new Timer(1000 * 60 * 5); //each 5 minutes
            timer.Elapsed += SendHeartbeatToServer;
            timer.Start();
        }



        public List<PeerInfo> GetPeerList()
        {
            var allPeers = client.GetPeerList(myself);
            var peersForMessaging = ChoosePeersForMessaging(allPeers);
            //return peersForMessaging;
            return allPeers; //TODO: Enable 10% list communication
        }

        public void SendLogToServer(string msg)
        {
            client.MakeLog(myself, msg);
        }

        private IContactService CreateClient()
        {
            var binding = new NetTcpBinding();
            var endpoint = new EndpointAddress(serverString);
            var myChannelFactory = new ChannelFactory<IContactService>(binding, endpoint);

            IContactService client = null;
            client = myChannelFactory.CreateChannel();
            return client;
        }

        private List<PeerInfo> ChoosePeersForMessaging(List<PeerInfo> allPeers)
        {
            //communicate with 10% of the network
            int noOfPeers = allPeers.Count / 10;
            List<int> indexList = GetRandomItemIndexes(noOfPeers, 0, allPeers.Count - 1);
            List<PeerInfo> res = new List<PeerInfo>();
            foreach (int index in indexList)
            {
                res.Add(allPeers.ElementAt(index));
            }
            return res;
        }

        private List<int> GetRandomItemIndexes(int noOfItems, int minValue, int maxValue)
        {
            List<int> res = new List<int>();
            Random rnd = new Random();
            int tmp = -1;
            while (res.Count < noOfItems)
            {
                tmp = rnd.Next(minValue, maxValue);
                if (!res.Contains(tmp))
                {
                    res.Add(tmp);
                }
            }
            return res;
        }

        private void SendHeartbeatToServer(object sender, ElapsedEventArgs e)
        {
            try
            {
                heartbeatClient.UpdateHeartbeat(myself);
            }
            catch { } //nothing to do, exception is raised when getting peer list
        }

    }
}