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

using System;
using System.Threading;
using Microsoft.Singularity;
using Microsoft.Singularity.Channels;
using Microsoft.SingSharp;
using Microsoft.SingSharp.Runtime;
using Microsoft.Singularity.Directory;

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

namespace Microsoft.Application.DSP
{
    public class NameServiceDSP
    {

        private static DirNode rootDir;
        private static string mountPoint;

        private static int Register(string! name, [Claims]ServiceProviderContract.Imp! imp)
        {
            // acquire namespace endpoint
            DirectoryServiceContract.Imp epNS = DirectoryService.NewClientEndpoint();
            mountPoint = name;

            try {
                epNS.SendRegister(Bitter.FromString2(name),imp);
                switch receive {
                    case epNS.AckRegister():
                        break;
                    case epNS.NakRegister(reject, error):
                        DebugStub.Break();
                        delete reject;
                        return -1;
                        break;
                    case epNS.ChannelClosed():
                        DebugStub.Break();
                        return -1;
                        break;
                    case epNS.NakRegisterReparse(char[]! in ExHeap path,
                               char[]! in ExHeap rest,
                               bool linkFound,
                               ServiceProviderContract.Imp:Start! reject) :
                        DebugStub.Break();
                        delete reject;
                        delete path;
                        delete rest;
                        return -1;
                        break;
                    case unsatisfiable:
                        Tracing.Log(Tracing.Debug,"unable to register NakConnect with Nameservice\n");
                        DebugStub.Break();
                        return -1;
                }
            }
            finally {
                delete epNS;
            }

            return 0;
        }

        private static int Deregister(string! name)
        {
            // acquire namespace endpoint
            DirectoryServiceContract.Imp epNS = DirectoryService.NewClientEndpoint();
            mountPoint = name;

            try {
                epNS.SendDeregister(Bitter.FromString2(name));
                switch receive {
                    case epNS.AckDeregister(service):
                        delete service;
                        break;
                    case epNS.NakDeregister(error):
                        DebugStub.Break();
                        break;
                    case epNS.ChannelClosed():
                        DebugStub.Break();
                        break;
                    case unsatisfiable:
                        Tracing.Log(Tracing.Debug,"unable to register NakConnect with Nameservice\n");
                        DebugStub.Break();
                        return -1;
                }
            }
            finally {
                delete epNS;
            }

            return 0;
        }

        public static void Initialize()
        {
            IAclPolicy _policy = new PathPolicyEngine();
            InstallAcls(_policy);
            AclCore _core = new AclCore(null, new DirAclCoreSupport());
            _core.Disable = true;
            rootDir = new DirNode("/", _core, _policy);
        }


        // in the fullness of time, we should read the server configuration
        // from a reified manifest including config information
        // for now, we will just add a rule to allow **any** access
        private static void InstallAcls(IAclPolicy! policy)
        {
            /*
            // read the rules section from the config
            XmlNode node = config.GetChild(PolicyListXmlTag);
            if (node == null) {
                return;
            }

            foreach (XmlNode! rule in node.Children) {
                if (rule.Name != "rule") {
                    continue;
                }

                string! resource = (!)rule.GetAttribute("resource", "");
                if (resource.Equals("")) {
                    continue;
                }
                string! aclstr = (!)rule.GetAttribute("acl", "");
                if (aclstr.Equals("")) {
                    continue;
                }

                policy.AddRule(resource, aclstr);
            }
            */
            policy.AddRule("/", "{/groups/anyall}");
        }

        public static void Finalize()
        {
            Deregister(mountPoint);
        }

        public static  void tell(string name)
        {
            Console.WriteLine("{0}: <registration path>", name);
        }

        public static  int  Main(string[]! args)
        {
            int status;
            Initialize();

            if (args.Length < 2) {
                tell(args[0]);
                return -1;
            }

            ServiceProviderContract.Imp! imp;
            ServiceProviderContract.Exp! s;
            ServiceProviderContract.NewChannel(out imp, out s);
            status = Register((!)args[1], imp);

            if (status != 0) {
                delete s;
                return status;
            }

             try {
                for (bool run = true; run;) {
                    switch receive {
                        // Listen for new connections
                        case s.Connect(ServiceContract.Exp:Start! candidate):
                                DirectoryServiceContract.Exp:Start exp = candidate as DirectoryServiceContract.Exp:Start!;
                                if (exp != null) {
                                    s.SendAckConnect();
                                    DirectoryServiceWorker.Create(rootDir,exp);
                                }
                                else s.SendNackConnect(candidate);
                                break;
                        case s.ChannelClosed() :
                            run = false;
                            Console.WriteLine("Channel Closed. DSP shutting down");
                            break;
                        case unsatisfiable:
                            run = false;
                            Console.WriteLine("Unsatisfiable. DSP shutting down");
                            break;
                    }
                }
            }
            finally {
            }
            delete s;
            Console.WriteLine(" last line of DSP... process should terminate");
            return 0;
        }
   }
}