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

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 System.Threading;

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.DiskRWNull
{
    [ConsoleCategory(HelpMessage="Null 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, 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);
          }
    }
    contract Hack
    {
        message Hak();
        state HACK : one { Hak? -> Hak! -> HACK; }
    }

    public class DiskBenchmark
    {
        static TRef<Hack.Imp:HACK> himp;
        static TRef<Hack.Exp:HACK> hexp;

        private const uint BytesPerSector = 512;
        private const uint SectorsPerMB = 1024 * 1024 / BytesPerSector;

        private 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;
        }

        private 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;

            Console.Write("{0}{1}.{2} ",
                          didRandom ? "R" : "S",
                          didRead ? "R" : "W",
                          blockBytes);

            Console.WriteLine("Ops/s: {0:f2}  MB/s: {1:f2}  Elapsed: {2:f2}  Check: {3:x}",
                              ops, ops * blockBytes / (1024.0 * 1024.0),
                              delta, nextOffset);
        }

        public static int DoDevice(string! deviceName,
                                   int     runNumber,
                                   ulong   blockCount,
                                   ulong   blockBytes,
                                   ulong   diskLimitMB,
                                   bool    doRandom,
                                   bool    doRead)
        {

            for (int i = 0; i < 4000; i++) {
                Hack.Imp! imp;
                Hack.Exp! exp;
                Hack.NewChannel(out imp, out exp);
                delete imp;
                delete exp;
            }
            ulong diskSectorCount = 4000000;

            // 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);

            Hack.Imp! imph = himp.Acquire();
            Hack.Exp! exph = hexp.Acquire();

            ///  
            ESet<Hack.Exp:HACK> eset = new ESet<Hack.Exp:HACK>();
            eset.Add(exph);
            ///  

            TimeSpan startTime = ProcessService.GetUpTime();

            for (ulong i = 0; i < blockCount; i++) {
                byte[]! in ExHeap outBuffer;
                if (doRead) {
                    //ProcessService.GetUpTime();

                    //imph.SendHak();
                    //switch receive { case exph.Hak(): exph.SendHak(); break; case unsatisfiable: throw new System.Exception(); }
                    //imph.RecvHak();

                    ///  
                    imph.SendHak();
                    switch receive {
                        case ep.Hak() in eset: ep.SendHak(); eset.Add(ep); break; case unsatisfiable: throw new System.Exception();
                    }
                    imph.RecvHak();
                    ///  

                    //imph.SendHak(); exph.RecvHak(); exph.SendHak(); imph.RecvHak();

                    outBuffer = buffer;
                }
                else {
                    outBuffer = buffer;
                }
                buffer = outBuffer;

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

            ///  
            imph.SendHak();
            switch receive {
                case ep.Hak() in eset: ep.SendHak(); hexp.Release(ep); break; case unsatisfiable: throw new System.Exception();
            }
            imph.RecvHak();
            himp.Release(imph);
            eset.Dispose();
            ///  

            //hexp.Release(exph);
            //himp.Release(imph);

            delete buffer;

            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}/{5}]",
                endGcCount - startGcCount,
                endGcBytes - startGcBytes,
                ProcessService.GetKernelInterruptCount() - startIrqCount,
                ProcessService.GetContextSwitchCount() - startSwitchCount,
                ProcessService.GetKernelGcCount() - startKernelGcCount,
                ProcessService.GetKernelGcCount());

            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 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;
            ulong dataMB        = (ulong) config.dataMB;
            bool  doWrite       = config.doRead;
            bool  doRead        = config.doWrite;
            bool   randomIO     = config.randomIO;

            bool   diskReadTest = false;

            Hack.Imp! imp;
            Hack.Exp! exp;
            Hack.NewChannel(out imp, out exp);
            himp = new TRef<Hack.Imp:HACK>(imp);
            hexp = new TRef<Hack.Exp:HACK>(exp);

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

            if (doRead == doWrite) {
                Console.WriteLine("Need to specify either read or write test.");
                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;
        }
    }
}