////////////////////////////////////////////////////////////////////////////////
//
//  Microsoft Research Singularity
//
//  Copyright (c) Microsoft Corporation.  All rights reserved.
//

using System;
using System.Runtime.CompilerServices;

using Microsoft.Singularity;
using Microsoft.Singularity.Directory;
using Microsoft.Singularity.V1.Services;
using Microsoft.Singularity.Io;
using Microsoft.Singularity.Channels;

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.Benchmarks.DiskRW
{
    [ConsoleCategory(HelpMessage="Disk r/w performance test", DefaultAction=true)]
    internal class Parameters
    {
        [InputEndpoint("data")]
        public readonly TRef<UnicodePipeContract.Exp:READY> Stdin;

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

        [StringParameter( "device", Mandatory=true, Position=0 , HelpMessage="Device to read/write")]
        internal string deviceName;

        [LongParameter( "b", Default=0, Mandatory=true, HelpMessage="Set block size to <n> bytes.")]
        internal long blockBytes;

        [LongParameter( "g", Default=1, HelpMessage="Repeat test n times.")]
        internal long repeatCount;

        [LongParameter( "l", Default=0, HelpMessage="Fix disk size limit at <n> megabytes.")]
        internal long diskLimitMB;

        [LongParameter( "m", Default=0, HelpMessage="Perform test with <n> megabytes of data.")]
        internal long dataMB;

        [LongParameter( "n", Default=0, HelpMessage="Perform test with <n> blocks of data.")]
        internal long blockCount;

        [LongParameter( "p", Default=0, HelpMessage="Pause <n> seconds between iterations")]
        internal long pauseSecs;

        [BoolParameter( "r", Default=false, HelpMessage="Perform disk read test.")]
        internal bool doRead ;

        [BoolParameter( "w", Default=false, HelpMessage="Perform disk write test.")]
        internal bool doWrite;

        [BoolParameter( "x", Default=false, HelpMessage="Perform test with random I/O offsets.")]
        internal bool randomIO;

        reflective internal Parameters();

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

    public class DiskBenchmark
    {
        internal const uint BytesPerSector = 512;
        internal const uint SectorsPerMB = 1024 * 1024 / BytesPerSector;

        public static DiskDeviceContract.Imp:Ready OpenDevice(String! devname)
        {
            DiskDeviceContract.Exp! exp;
            DiskDeviceContract.Imp! imp;
            DiskDeviceContract.NewChannel(out imp, out exp);
            DirectoryServiceContract.Imp ns;

            ErrorCode errorOut;
            // get NS endpoint
            ns = DirectoryService.NewClientEndpoint();
            bool success;
            success  = SdsUtils.Bind(devname,ns, exp, out errorOut);
            if (!success) {
                Console.WriteLine("Bind of {0} failed. Reason:{1}\n",
                                  devname, SdsUtils.ErrorCodeToString(errorOut));
                delete imp;
                delete ns;
                return null;
            }
            switch receive {
                    case imp.Success():
                        break;
                    case imp.ContractNotSupported():
                        Console.WriteLine("{0} does not support DiskDevice", devname);
                        delete imp;
                        delete ns;
                        return null;
                    case imp.ChannelClosed():
                        Console.WriteLine("DiskDevice channel to {0} closed unexpectedly", devname);
                        delete imp;
                        delete ns;
                        return null;
                }

            delete ns;
            return imp;
        }

        internal static ulong GetRandomOffset(SRandom! rng,
                                             ulong    diskSectorCount,
                                             ulong    blockBytes)
        {
            ulong maxBlock = diskSectorCount * 512 / blockBytes;
            ulong offset = 0;
            for (int i = 0; i < 64; i += 30) {
                offset ^= (ulong)(rng.Next() << i);
            }
            offset &= 0x7fffffffffffffff;
            offset %= maxBlock;
            return offset * blockBytes;
        }

        internal static void DisplayPerf(bool     didRead,
                                        bool     didRandom,
                                        TimeSpan elapsed,
                                        ulong    blockCount,
                                        ulong    blockBytes,
                                        ulong    nextOffset)
        {
            double delta = (double)elapsed.Ticks / TimeSpan.TicksPerSecond;
            double ops   = (double)blockCount / delta;

            string output = String.Format(
                "{0}{1} {2} {3} Ops/s: {4:f2}  MB/s: {5:f2}  Elapsed: {6:f2}  Check: {7:x}",
                didRandom ? "R" : "S",
                didRead ? "R" : "W",
                blockBytes,
                blockCount,
                ops,
                ops * blockBytes / (1024.0 * 1024.0),
                delta,
                nextOffset);

            Console.WriteLine(output);
            DebugStub.WriteLine(output);
        }

        public static int DoDevice(string! deviceName,
                                   int     runNumber,
                                   ulong   blockCount,
                                   ulong   blockBytes,
                                   ulong   diskLimitMB,
                                   bool    doRandom,
                                   bool    doRead)
        {
            //
            // Open device
            //
            DiskDeviceContract.Imp imp = OpenDevice(deviceName);
            if (null == imp) {
                Console.WriteLine("Could not open {0}", deviceName);
                return 1;
            }

            //
            // Get disk size
            //
            ulong diskSectorCount;

            imp.SendGetSectorCount();
            switch receive {
                    case imp.AckGetSectorCount(sectorCount):
                        diskSectorCount = sectorCount;
                        break;
                    case imp.ChannelClosed():
                        Console.WriteLine("Channel closed unexpectedly");
                        throw new Exception("Unexpected channel close");
                }

            // Constrain disk size if user requested
            if (diskLimitMB != 0 &&
                diskSectorCount > diskLimitMB * SectorsPerMB)
            {
                diskSectorCount = diskLimitMB * SectorsPerMB;
            }
            diskLimitMB = diskSectorCount / SectorsPerMB;

            // Constrain block count if it overflows available blocks
            if (blockCount * blockBytes > diskSectorCount * BytesPerSector) {
                blockCount = diskSectorCount * BytesPerSector / blockBytes;
            }

            if (runNumber == 0) {
                Console.WriteLine("# Type:  {0} {1}",
                                  doRandom ? "Random" : "Sequential",
                                  doRead ? "Read" : "Write");
                Console.WriteLine("# Disk:  {0} MB",
                                  diskSectorCount / SectorsPerMB);
                Console.WriteLine("# Limit: {0} MB", diskLimitMB);
                Console.WriteLine("# Work:  {0:f2} MB",
                                  blockCount * blockBytes / (1024.0 * 1024.0));
                Console.WriteLine("# Ops:   {0}", blockCount);
            }

            byte[] in ExHeap buffer = new [ExHeap] byte [blockBytes];

            SRandom rng = new SRandom();

            ulong diskPos = 0;
            if (doRandom) {
                diskPos = GetRandomOffset(rng, diskSectorCount, blockBytes);
            }

            long startIrqCount = ProcessService.GetKernelInterruptCount();
            long startSwitchCount = ProcessService.GetContextSwitchCount();
            long startKernelGcCount = ProcessService.GetKernelGcCount();
            int  startGcCount;
            long startGcMillis;
            long startGcBytes;
            GC.PerformanceCounters(out startGcCount,
                                   out startGcMillis,
                                   out startGcBytes);

            TimeSpan startTime = ProcessService.GetUpTime();

            for (ulong i = 0; i < blockCount; i++) {
                ulong sector = diskPos / BytesPerSector;

                byte[]! in ExHeap outBuffer;
                if (doRead) {
                    imp.SendRead(buffer, 0, blockBytes, sector);
                    imp.RecvAckRead(out outBuffer);
                }
                else {
                    imp.SendWrite(buffer, 0, blockBytes, sector);
                    imp.RecvAckWrite(out outBuffer);
                }
                buffer = outBuffer;

                if (doRandom) {
                    diskPos =
                        GetRandomOffset(rng, diskSectorCount, blockBytes);
                }
                else {
                    diskPos += blockBytes;
                }
            }
            TimeSpan endTime = ProcessService.GetUpTime();

            delete buffer;
            delete imp;

            DisplayPerf(doRead, doRandom, endTime - startTime,
                        blockCount, blockBytes, diskPos);

            int  endGcCount;
            long endGcMillis;
            long endGcBytes;
            GC.PerformanceCounters(out endGcCount,
                                   out endGcMillis,
                                   out endGcBytes);

            Console.WriteLine("[AppGC :- cnt {0} bytes {1} Kern: ints {2} swi {3} gcs {4}]",
                              endGcCount - startGcCount,
                              endGcBytes - startGcBytes,
                              ProcessService.GetKernelInterruptCount() - startIrqCount,
                              ProcessService.GetContextSwitchCount() - startSwitchCount,
                              ProcessService.GetKernelGcCount() - startKernelGcCount);

            return 0;
        }

        public static bool ParseNumber(string! arg,
                                       string! name,
                                       out ulong value)
        {
            // arg should look like "[-/][A-z]:[0-9]"
            if (arg.Length >= 4) {
                try {
                    value = UInt64.Parse(arg.Substring(3));
                    return true;
                }
                catch (FormatException) {
                }
                catch (OverflowException) {
                }
            }
            Console.WriteLine("Could not parse {0}", name);
            value = 0;
            return false;
        }

        internal static void Usage()
        {
        }

        internal static int AppMain(Parameters! config)
        {
            string deviceName   = config.deviceName;
            ulong  blockBytes   = (ulong) config.blockBytes;
            ulong  blockCount   = (ulong) config.blockCount;
            ulong  diskLimitMB  = (ulong) config.diskLimitMB;
            ulong  repeatCount  = (ulong) config.repeatCount;
            ulong  pauseSecs    = (ulong) config.pauseSecs;
            bool   randomIO     = config.randomIO;
            bool   diskReadTest = false;
            bool  doWrite       = config.doWrite;
            bool  doRead        = config.doRead;
            ulong dataMB        = (ulong) config.dataMB;

            if (blockBytes < 512 || (blockBytes & (blockBytes - 1)) != 0) {
                Console.WriteLine("Block size must be a power of two greater than or equal to 512.");
                Usage();
                return -1;
            }

            if (doRead == doWrite) {
                Console.WriteLine("Need to specify either read or write test.");
                Usage();
                return -1;
            }
            else if (doRead) {
                diskReadTest = true;
            }

            if (dataMB != 0) {
                blockCount = dataMB * 1024 * 1024 / blockBytes;
            }

            for (int run = 0; run < (int)repeatCount; run++) {
                if (run != 0) {
                    System.Threading.Thread.Sleep(1000 * (int)pauseSecs);
                }

                Tracing.Log(Tracing.Debug, "Starting diskrw run {0}",
                            (UIntPtr) run);
                if (DoDevice((!)deviceName, run, blockCount, blockBytes,
                             diskLimitMB, randomIO, diskReadTest) != 0) {
                    return -1;
                }
                Tracing.Log(Tracing.Debug, "Ending diskrw run {0}",
                            (UIntPtr) run);
            }
            return 0;
        }
    }
}