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

using System;
using System.Diagnostics;
using System.Threading;
using Microsoft.Singularity;
using Microsoft.Singularity.Directory;
using Microsoft.Singularity.Channels;
using Microsoft.Singularity.FileSystem;
using Microsoft.Singularity.V1.Services;

namespace FileSystem.Utils
{
    public class DirectoryUtils
    {
        // Find the directory that encloses the named file/dir
        internal static DirectoryServiceContract.Imp:Ready FindDir(string! path)
        {
            DirectoryServiceContract.Imp! rootNS = DirectoryService.NewClientEndpoint();
            try {
                return FindDir(path, rootNS); 
            }
            finally {
                delete rootNS; 
            }
        }

        // Find the directory that encloses the named file/dir
        internal static DirectoryServiceContract.Imp:Ready FindDir(string! path,  DirectoryServiceContract.Imp! ds)
        {
            string dirPath, leafName;
            PathUtils.SplitPath(path, out dirPath, out leafName);

            if ((dirPath == null) || (dirPath == ""))
            {
                // Invalid path; no leading directory component
                return null;
            }

            // Ask for just the enclosing directory
            return OpenDir(dirPath, ds);
        }

        public static DirectoryServiceContract.Imp:Ready OpenDir(string! dirPath)
        {
            DirectoryServiceContract.Imp! rootNS = DirectoryService.NewClientEndpoint();

            try {
                return OpenDir(dirPath, rootNS);
            }
            finally {
                delete rootNS;
            }
        }

        public static DirectoryServiceContract.Imp:Ready OpenDir(string! dirPath, DirectoryServiceContract.Imp! rootNS)
        {
            DirectoryServiceContract.Imp! dirClient;
            DirectoryServiceContract.Exp! dirServer;
            DirectoryServiceContract.NewChannel(out dirClient, out dirServer);

            ErrorCode errorOut; 
            bool ok = SdsUtils.Bind(dirPath, rootNS, dirServer, out errorOut);
            if (!ok) {
                delete dirClient; 
                return null;
            } 
            else {
                dirClient.RecvSuccess();
                return dirClient;
            }
        }

        // 0 is success
        public static int DeleteDirectory (string! dirPath)
        {
            string dirName = PathUtils.FileFromPath(dirPath);

            if (dirName == null) {
                // No trailing file part
                return -1;
            }

            DirectoryServiceContract.Imp dirClient = FindDir(dirPath);

            if (dirClient == null)
            {
                // Couldn't open enclosing directory
                return -1;
            }

            dirClient.SendDeleteDirectory(Bitter.FromString2(dirName));

            switch receive {
                case dirClient.NakDeleteDirectory(error):
                    // Failed; no such directory?
                    delete dirClient;
                    return -1;

                case dirClient.AckDeleteDirectory():
                    break;

                case dirClient.ChannelClosed():
                    // Unexpected
                    delete dirClient;
                    return -1;
            }

            delete dirClient;
            return 0;
        } //DeleteDirectory

#if !REMOVE
        //REMOVE version that does not have ds endpoint
        public static int CreateDirectory (string! dirPath)
        {
            DirectoryServiceContract.Imp! rootNS = DirectoryService.NewClientEndpoint();
            try {
                return CreateDirectory(dirPath, rootNS); 
            }
            finally {
                delete rootNS; 
            }
        }
#endif
        public static int CreateDirectory (string! dirPath, DirectoryServiceContract.Imp! ds)
        {
            string dirName = PathUtils.FileFromPath(dirPath);

            if (dirName == null) {
                // No trailing file part
                return -1;
            }

            DirectoryServiceContract.Imp dirClient = FindDir(dirPath);

            if (dirClient == null)
            {
                // Couldn't open enclosing directory
                return -1;
            }

            dirClient.SendCreateDirectory(Bitter.FromString2(dirName));

            switch receive {
                case dirClient.NakCreateDirectory(error):
                    // Failure
                    delete dirClient;
                    return -1;

                case dirClient.AckCreateDirectory():
                    // Success
                    break;

                case dirClient.ChannelClosed():
                    // Unexpected
                    delete dirClient;
                    return -1;
            }

            delete dirClient;
            return 0;
        } //CreateDirectory

        // Outparam is only valid if return value is 0 (success)
        public static int PathIsDirectory(string! dirPath, out bool isDir)
        {
            isDir = false;

            // Get attributes as though this is a file
            NodeType nodeType;
            long size;
            ErrorCode error;
                
            DirectoryServiceContract.Imp! rootNS = DirectoryService.NewClientEndpoint();
            bool ok  = FileUtils.GetAttributes(dirPath, rootNS, out size, out nodeType, out  error);
            delete rootNS; 
            
            if (!ok)
            {
                return -1;
            }

            if (nodeType != NodeType.Directory)
            {
                Debug.Assert(size == 0);
                isDir = true;
            }

            return 0;
        } //PathIsDirectory
    }
}