///////////////////////////////////////////////////////////////////////////////
//
//  Microsoft Research Singularity
//
//  Copyright (c) Microsoft Corporation.  All rights reserved.
//
//  File:   NetStack.sg
//
//  Note:
//

using System;
using System.Runtime.InteropServices;
using System.Runtime.CompilerServices;
using System.Threading;

using Microsoft.SingSharp;
using Microsoft.Singularity;
using Microsoft.Singularity.Channels;
using Microsoft.Singularity.Directory;
using Microsoft.Singularity.Security;
using Microsoft.Singularity.Io;
using Microsoft.Singularity.Configuration;
using Microsoft.Singularity.ServiceManager;

[assembly: ApplicationPublisherAttribute("singularity.microsoft.com")]
[assembly: AssertPrivilegeAttribute("$register-privilege.localhost")]

namespace NetStack
{
    using NetStack.Channels.Private;
    using NetStack.Channels.Nic;

    [ConsoleCategory(HelpMessage="Runs the NetStack as an application", DefaultAction=true)]
    internal class Parameters
    {
        [InputEndpoint("data")]
        public readonly TRef<UnicodePipeContract.Exp:READY> Stdin;

        [OutputEndpoint("data")]
        public readonly TRef<UnicodePipeContract.Imp:READY> Stdout;

        [Endpoint]
        public readonly TRef<DirectoryServiceContract.Imp:Start> nsRef;

        reflective internal Parameters();

        internal int AppMain() {
            return NetStackApplication.Main();
        }
    }

    /// <summary>
    /// The NetStack Application class is a single instance service running
    /// on a host.  When it runs it attempts to register as /service/netstack;
    /// success indicates no other instances and it then initializes
    /// the various NetStack subsystems.
    /// </summary>
    class NetStackApplication
    {
        DNSExpManager! dnsManager;
        RoutingExpManager! routingManager;
        TcpExpManager! tcpManager;
        UdpExpManager! udpManager;
        IPExpManager! ipManager;

        NetStackApplication()
        {
            NetStack.Runtime.StaticConfiguration.Initialize();
            NetStack.Runtime.StaticConfiguration.Start();

            dnsManager     = new DNSExpManager();
            routingManager = new RoutingExpManager();
            tcpManager     = new TcpExpManager();
            udpManager     = new UdpExpManager();
            ipManager      = new IPExpManager();
        }

        bool Start()
        {
            try {
                ipManager.Start();

                routingManager.Start();
                tcpManager.Start();
                udpManager.Start();
                dnsManager.Start();

                NicFactory.Probe();

                return true;
            }
            catch (Exception ex) {
                Dbg("An exception occurred during service startup: " + ex.Message);
                return false;
            }
        }

        void ServiceMain()
        {
            bool run = true;

            while (run) {
                Thread.Sleep(1000);
            }
        }

        void Stop()
        {
            // Stop the service provider threads.
            Dbg("Stopping service provider threads");
            dnsManager.Stop();
            routingManager.Stop();
            ipManager.Stop();
            tcpManager.Stop();
            udpManager.Stop();

            // StaticConfiguration.Stop() walks the list of installed modules and calls
            // the StopModule() method of each.  We do this after stopping the service
            // provider threads.
            Dbg("Stopping protocol modules");
            NetStack.Runtime.StaticConfiguration.Stop();
        }

        public static int Main()
        {
            NetStackApplication app = new NetStackApplication();

            try {
                return app.Run();
            }
            finally {
                Dbg("NetStack is terminating.");
            }
        }

        int Run()
        {
            if (Start()) {
                ServiceMain();
                Stop();
                return 0;
            }
            else {
                Dbg("Sending StartFailed to Service Manager.");
                Stop();
                return -1;
            }
        }

        static void Dbg(string! line)
        {
            DebugStub.WriteLine(line);
        }

        static void Dbg(string! format, params object[]! args)
        {
            Dbg(String.Format(format, args));
        }
    }
}