////////////////////////////////////////////////////////////////////////////////
//
//  Microsoft Research Singularity
//
//  Copyright (c) Microsoft Corporation.  All rights reserved.
//
//  File:   Getsymlink.sg
//
//  Note:
//
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.SingSharp;
using Microsoft.SingSharp.Runtime;

using Microsoft.Contracts;
using Microsoft.SingSharp.Reflection;
using Microsoft.Singularity.Applications;
using Microsoft.Singularity.Io;
using Microsoft.Singularity.Configuration;
[assembly: Transform(typeof(ApplicationResourceTransform))]

namespace Microsoft.Singularity.Applications {
    [ConsoleCategory(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;

        [StringParameter( "path", Position=0, Mandatory=true)]
        internal string nsPath;

        reflective internal Parameters();

        internal int AppMain() {
            return GetSymLink.AppMain(this);
        }
    }

    class GetSymLink 
    {
        private static void tell()
        {
            Console.WriteLine("Getsymlink <link name>.");
            Console.WriteLine("    returns value of link located at <link name>");
        }

        internal static int AppMain(Parameters! config)
        {

            ErrorCode errorOut;
            string link; 
            
            DirectoryServiceContract.Imp ds = (config.nsRef).Acquire(); 
            if (ds == null) { 
                throw new Exception("Unable to acquire handle to the Directory Service root"); 
            } 
            ds.RecvSuccess();

            bool ok = SdsUtils.GetLinkValue(config.nsPath, ds, out link, out errorOut);

            if (!ok) {
                Console.WriteLine("{0} ({1}) failed. reason: {2}\n", 
                                   "getsymlink", config.nsPath, SdsUtils.ErrorCodeToString(errorOut) );
                delete ds;
                return -1;
            }
            
            Console.WriteLine("Link: {0} -> {1}", config.nsPath,link); 
            delete ds; 
            return 0;
        }
    }//SymbolicLink
}//namespace