////////////////////////////////////////////////////////////////////////////////
//
//  Microsoft Research Singularity
//
//  Copyright (c) Microsoft Corporation.  All rights reserved.
//
//  Note:   Used for testing the namespace service.
//          register /dev/NakConnect  in the namespace.
//          will always Nak any Connect requests.
//

using System;
using System.Runtime.CompilerServices;
//using System.Threading;
using Microsoft.Singularity;
using Microsoft.Singularity.Directory;
using Microsoft.Singularity.V1.Services;
using Microsoft.Singularity.Channels;
using Microsoft.Singularity.Security;

using Microsoft.SingSharp;
using Microsoft.SingSharp.Runtime;
[assembly: ApplicationPublisherAttribute("singularity.microsoft.com")]
[assembly: AssertPrivilegeAttribute("$register-privilege.localhost")]

namespace Microsoft.Singularity.Applications
{
    public static class NakConnect
    {
        static string hang = "/service/channelhang";
        static string nakConn = "/service/nakconnect";
        static string nakRunning = "/service/nakrunning";
        static string closed = "/service/channelclosed";

        private static bool Register(DirectoryServiceContract.Imp! ds,
                                     string! name,
                                     [Claims]ServiceProviderContract.Imp! imp)
        {
            // acquire namespace endpoint

            ErrorCode errorOut;
            ServiceProviderContract.Imp:Start  service;
            bool ok = SdsUtils.Register(name, ds, imp, out errorOut);
            if (!ok) {
                Console.WriteLine(" Registration of {0} failed. Reason: {1}",
                                  name,
                                  SdsUtils.ErrorCodeToString(errorOut)
                                  );

            }
            return ok;

     }

        private static  bool  DoDeregister(DirectoryServiceContract.Imp! ds, string! path)
        {
            ErrorCode errorOut;
            ServiceProviderContract.Imp:Start  service;
            bool ok = SdsUtils.Deregister(path, ds, out service, out errorOut);
            if (!ok) DebugStub.Break();
            delete service;
            return ok;
        }

        static void Finalize()
        {
            Console.WriteLine("NakService Finalizer called.");
            DebugStub.Break();
            DirectoryServiceContract.Imp ds = DirectoryService.NewClientEndpoint();
            try   {
                DoDeregister(ds, hang);
                DoDeregister(ds, nakConn);
                DoDeregister(ds, closed);
            }
            finally {
                delete ds;
            }
        }

        static void CleanUp()
        {
            Console.WriteLine("NakService Finalizer called.");
            DirectoryServiceContract.Imp ds = DirectoryService.NewClientEndpoint();
            try   {
                DoDeregister(ds, hang);
                DoDeregister(ds, nakConn);
                DoDeregister(ds, closed);
            }
            finally {
                delete ds;
            }
        }

        public static int Main(String[]! args)
        {

            DirectoryServiceContract.Imp ds = DirectoryService.NewClientEndpoint();

            // register "/service/nakconnect" in NS
            ServiceProviderContract.Imp! imp;
            ServiceProviderContract.Exp! s;
            ServiceProviderContract.NewChannel(out imp, out s);
            bool ok = NakConnect.Register(ds, nakConn, imp);

            if (!ok) {
                delete s;
                delete ds;
                return -1;
            }

            // register "/service/channelhang" in NS
            // we keep the exp alive but we never listen
            ServiceProviderContract.Imp! imp3;
            ServiceProviderContract.Exp! s3;
            ServiceProviderContract.NewChannel(out imp3, out s3);
            ok = NakConnect.Register(ds, hang, imp3);
            if (!ok) {
                delete s;
                delete s3;
                delete ds;
                return -1;
            }

            // register "/service/nakrunning" in NS
            // we keep the exp alive but we never listen
            ServiceProviderContract.Imp! imp4;
            ServiceProviderContract.Exp! s4;
            ServiceProviderContract.NewChannel(out imp4, out s4);
            ok = NakConnect.Register(ds, nakRunning, imp4);
            if (!ok) {
                delete s;
                delete s3;
                delete ds;
                delete s4;
                return -1;
            }

            // register "/service/channelclosed" in NS
            // we pass the imp on to the NS but close down the exp end
            ServiceProviderContract.Imp! imp2;
            ServiceProviderContract.Exp! s2;
            ServiceProviderContract.NewChannel(out imp2, out s2);
            ok = NakConnect.Register(ds, closed, imp2);

            delete s2; // ensure channel closed on other end

            if (!ok) {
                delete s;
                delete s3;
                delete s4;
                delete ds;
                return -1;
            }

            // enter loop to receive Connect messages and always return NACK

             try {
                for (bool run = true; run;) {
                    switch receive {
                    // Listen for new connections
                    case s.Connect(candidate):
                        Console.WriteLine("Nak Service NACKing....");
                        s.SendNackConnect(candidate);
                        break;
                    case s4.Connect(candidate):
                        Console.WriteLine("Nak Service NACKing....");
                        s.SendAckConnect();
                        delete candidate;
                        break;
                    case s.ChannelClosed() :
                        Console.WriteLine("NakConnect channel closed");
                        run = false;
                        break;
                    case s4.ChannelClosed() : //IsRunning has closed
                        Console.WriteLine("NakRunning channel closed");
                        run = false;
                        break;
                   }
                }
            }
            finally {
                CleanUp();
            }
            Console.WriteLine("terminating NakService cleanly");
            delete s;
            delete s3;
            delete s4;
            delete ds;
            SdsUtils.FlushCache();

            return 0;
        }

    } // class NakConnect
}//namespace