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

using DirectoryServices.Utils;

using Microsoft.SingSharp;
using Microsoft.SingSharp.Reflection;

using Microsoft.Singularity.Channels;
using Microsoft.Singularity.Configuration;
using Microsoft.Singularity.Directory;
using Microsoft.Singularity.Io;
using Microsoft.Singularity.Security;
using Microsoft.Singularity.Services;
using Microsoft.Singularity.Services.Fat.Contracts;

using System;

using MSD = Microsoft.Singularity.Directory;

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

[assembly: Transform(typeof(ServiceResourceTransform))]

namespace Microsoft.Singularity.Services.Fat.Fs
{
    [Category("Service")]
    public sealed class FsResources
    {
        [Endpoint]
        internal TRef<FatClientContract.Exp:Start> managerTRef;

        reflective private FsResources();
    }

    internal sealed class Fs
    {
        internal static int AppMain(FsResources! resources)
        {
            FatClientContract.Exp:Start! managerExp =
                resources.managerTRef.Acquire();

            bool shutdown = false;
            while (!shutdown) {
                switch receive {
                    case managerExp.Mount(mountSettings):
                        Mount(managerExp, mountSettings);
                        return 0;
                        break;

                    case managerExp.GetPreferredFormatSettings(diskPath):
                        Format.SendPreferredFormatSettings(managerExp,
                                                           diskPath);
                        break;

                    case managerExp.Format(diskPath, label, settings):
                        Format.DoFormat(managerExp, diskPath, label, settings);
                        break;

                    case managerExp.ChannelClosed():
                        shutdown = true;
                        break;
                }
            }
            delete managerExp;

            return 0;
        }

        private static ServiceProviderContract.Exp
        InstallMountPath(string! path)
        {
            ServiceProviderContract.Imp! spImp;
            ServiceProviderContract.Exp! spExp;
            ServiceProviderContract.NewChannel(out spImp, out spExp);

            DirectoryServiceContract.Imp dsRootImp = DirectoryService.NewClientEndpoint();
            try {
                dsRootImp.SendRegister(Bitter.FromString2(path), spImp);
                switch receive {
                    case dsRootImp.AckRegister():
                        return spExp;

                    case dsRootImp.NakRegister(rejected, errorCode):
                        DebugStub.Print(
                            "FatFs failed to register {0} reason {1}\n",
                            __arglist(path,
                                      SdsUtils.ErrorCodeToString(errorCode))
                            );
                        delete rejected;
                        delete spExp;
                        break;
                }
            }
            finally {
                delete dsRootImp;
            }
            return null;
        }

        private static void
        Mount([Claims] FatClientContract.Exp! managerExp,
              [Claims] FatMountSettings*! in ExHeap fms)
        {
            ServiceProviderContract.Exp spExp;

            try {
                DebugStub.Print(
                    "FatFs mount disk path = {0} mount path = {1}",
                    __arglist(fms->DiskPath, fms->MountPath));
                spExp = InstallMountPath(fms->MountPath);
                if (spExp == null) {
                    managerExp.SendFail(FatContractErrorCode.PathUnavailable);
                    delete managerExp;
                    return;
                }

                // TODO: Check sanity of cache size
                // and fail if outside valid bounds.

                DebugStub.Print("Starting mount...\n");
                FatContractErrorCode error =
                    FatVolume.Mount(fms->DiskPath,
                                    fms->ReadOnly,
                                    fms->CacheMB,
                                    fms->DirectoryCacheSize,
                                    fms->FileCacheSize,
                                    fms->WriteQueueSize
                                    );

                if (error != FatContractErrorCode.NoError) {
                    managerExp.SendFail(error);
                    delete managerExp;
                    delete spExp;
                    DebugStub.Print("...failed.\n");
                    return;
                }

                DebugStub.Print("...completed.\n");
                DebugStub.Print("SectorBytes = {0}\n",
                                __arglist(
                                    FatVolume.BpbSummary.BytesPerSector
                                    )
                                );
                DebugStub.Print("SectorsPerCluster = {0} ({1} bytes)\n",
                                __arglist(
                                    FatVolume.BpbSummary.SectorsPerCluster,
                                    FatVolume.BpbSummary.SectorsPerCluster *
                                    FatVolume.BpbSummary.BytesPerSector
                                    )
                                );

                managerExp.SendSuccess();
                (new ChannelIo(managerExp, spExp)).Run();
                FatVolume.Unmount();
            }
            finally {
                delete fms;
            }
        }
    }
}