/*

  Version: MPL 1.1/GPL 2.0/LGPL 2.1

  The contents of this file are subject to the Mozilla Public License Version

  1.1 (the "License"); you may not use this file except in compliance with

  the License. You may obtain a copy of the License at

  http://www.mozilla.org/MPL/

  Software distributed under the License is distributed on an "AS IS" basis,

  WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License

  for the specific language governing rights and limitations under the License.

  The Original Code is the Open Hardware Monitor code.

  The Initial Developer of the Original Code is 

  Michael Möller <m.moeller@gmx.ch>.

  Portions created by the Initial Developer are Copyright (C) 2010-2011

  the Initial Developer. All Rights Reserved.

  Contributor(s):

  Alternatively, the contents of this file may be used under the terms of

  either the GNU General Public License Version 2 or later (the "GPL"), or

  the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),

  in which case the provisions of the GPL or the LGPL are applicable instead

  of those above. If you wish to allow use of your version of this file only

  under the terms of either the GPL or the LGPL, and not to allow others to

  use your version of this file under the terms of the MPL, indicate your

  decision by deleting the provisions above and replace them with the notice

  and other provisions required by the GPL or the LGPL. If you do not delete

  the provisions above, a recipient may use your version of this file under

  the terms of any one of the MPL, the GPL or the LGPL.

*/

using System;

using System.Collections.Generic;

using System.Diagnostics;

using System.Globalization;

using System.Runtime.InteropServices;

using System.Text;

using System.Threading;

namespace OpenHardwareMonitor.Hardware.CPU {

  internal class GenericCPU : Hardware {

    protected readonly CPUID[][] cpuid;

    protected readonly uint family;

    protected readonly uint model;

    protected readonly uint stepping;

    protected readonly int processorIndex;

    protected readonly int coreCount;

    private readonly bool hasModelSpecificRegisters;

    private readonly bool hasTimeStampCounter;

    private readonly bool isInvariantTimeStampCounter;

    private readonly double estimatedTimeStampCounterFrequency;

    private readonly double estimatedTimeStampCounterFrequencyError;

    private ulong lastTimeStampCount;

    private long lastTime;

    private double timeStampCounterFrequency;

    private readonly Vendor vendor;

    private readonly CPULoad cpuLoad;

    private readonly Sensor totalLoad;

    private readonly Sensor[] coreLoads;

    protected string CoreString(int i) {

      if (coreCount == 1)

        return "CPU Core";

      else

        return "CPU Core #" + (i + 1);

    }

    public GenericCPU(int processorIndex, CPUID[][] cpuid, ISettings settings)

      : base(cpuid[0][0].Name, CreateIdentifier(cpuid[0][0].Vendor, 

      processorIndex), settings)

    {

      this.cpuid = cpuid;

      this.vendor = cpuid[0][0].Vendor;

      this.family = cpuid[0][0].Family;

      this.model = cpuid[0][0].Model;

      this.stepping = cpuid[0][0].Stepping;

      this.processorIndex = processorIndex;

      this.coreCount = cpuid.Length;  

      // check if processor has MSRs

      if (cpuid[0][0].Data.GetLength(0) > 1

        && (cpuid[0][0].Data[1, 3] & 0x20) != 0)

        hasModelSpecificRegisters = true;

      else

        hasModelSpecificRegisters = false;

      // check if processor has a TSC

      if (cpuid[0][0].Data.GetLength(0) > 1

        && (cpuid[0][0].Data[1, 3] & 0x10) != 0)

        hasTimeStampCounter = true;

      else

        hasTimeStampCounter = false;

      // check if processor supports an invariant TSC 

      if (cpuid[0][0].ExtData.GetLength(0) > 7

        && (cpuid[0][0].ExtData[7, 3] & 0x100) != 0)

        isInvariantTimeStampCounter = true;

      else

        isInvariantTimeStampCounter = false;

      if (coreCount > 1)

        totalLoad = new Sensor("CPU Total", 0, SensorType.Load, this, settings);

      else

        totalLoad = null;

      coreLoads = new Sensor[coreCount];

      for (int i = 0; i < coreLoads.Length; i++)

        coreLoads[i] = new Sensor(CoreString(i), i + 1,

          SensorType.Load, this, settings);

      cpuLoad = new CPULoad(cpuid);

      if (cpuLoad.IsAvailable) {

        foreach (Sensor sensor in coreLoads)

          ActivateSensor(sensor);

        if (totalLoad != null)

          ActivateSensor(totalLoad);

      }

      if (hasTimeStampCounter) {

        ulong mask = ThreadAffinity.Set(1UL << cpuid[0][0].Thread);

        EstimateTimeStampCounterFrequency(

          out estimatedTimeStampCounterFrequency, 

          out estimatedTimeStampCounterFrequencyError);  

        ThreadAffinity.Set(mask);

      } else {

        estimatedTimeStampCounterFrequency = 0;

      }

      timeStampCounterFrequency = estimatedTimeStampCounterFrequency;                  

    }

    private static Identifier CreateIdentifier(Vendor vendor,

      int processorIndex) 

    {

      string s;

      switch (vendor) {

        case Vendor.AMD: s = "amdcpu"; break;

        case Vendor.Intel: s = "intelcpu"; break;

        default: s = "genericcpu"; break;

      }

      return new Identifier(s,

        processorIndex.ToString(CultureInfo.InvariantCulture));

    }

    private void EstimateTimeStampCounterFrequency(out double frequency, 

      out double error) 

  {     

      double f, e;

      // preload the function

      EstimateTimeStampCounterFrequency(0, out f, out e);

      EstimateTimeStampCounterFrequency(0, out f, out e);

      // estimate the frequency

      error = double.MaxValue;

      frequency = 0;

      for (int i = 0; i < 5; i++) {

        EstimateTimeStampCounterFrequency(0.025, out f, out e);

        if (e < error) {

          error = e;

          frequency = f;

        }

        if (error < 1e-4)

          break;

      }                

    }

    private void EstimateTimeStampCounterFrequency(double timeWindow, 

      out double frequency, out double error) 

    {

      long ticks = (long)(timeWindow * Stopwatch.Frequency);

      ulong countBegin, countEnd;

      long timeBegin = Stopwatch.GetTimestamp() +

        (long)Math.Ceiling(0.001 * ticks);

      long timeEnd = timeBegin + ticks;

      while (Stopwatch.GetTimestamp() < timeBegin) { }

      countBegin = Opcode.Rdtsc();

      long afterBegin = Stopwatch.GetTimestamp();

      while (Stopwatch.GetTimestamp() < timeEnd) { }

      countEnd = Opcode.Rdtsc();

      long afterEnd = Stopwatch.GetTimestamp();

      double delta = (timeEnd - timeBegin);

      frequency = 1e-6 * 

        (((double)(countEnd - countBegin)) * Stopwatch.Frequency) / delta;

      double beginError = (afterBegin - timeBegin) / delta;

      double endError = (afterEnd - timeEnd) / delta;

      error = beginError + endError;

    }

    private static void AppendMSRData(StringBuilder r, uint msr, int thread) {

      uint eax, edx;

      if (Ring0.RdmsrTx(msr, out eax, out edx, 1UL << thread)) {

        r.Append(" ");

        r.Append((msr).ToString("X8", CultureInfo.InvariantCulture));

        r.Append("  ");

        r.Append((edx).ToString("X8", CultureInfo.InvariantCulture));

        r.Append("  ");

        r.Append((eax).ToString("X8", CultureInfo.InvariantCulture));

        r.AppendLine();

      }

    }

    protected virtual uint[] GetMSRs() {

      return null;

    }

    public override string GetReport() {

      StringBuilder r = new StringBuilder();

      switch (vendor) {

        case Vendor.AMD: r.AppendLine("AMD CPU"); break;

        case Vendor.Intel: r.AppendLine("Intel CPU"); break;

        default: r.AppendLine("Generic CPU"); break;

      }

      r.AppendLine();

      r.AppendFormat("Name: {0}{1}", name, Environment.NewLine);

      r.AppendFormat("Number of Cores: {0}{1}", coreCount,

        Environment.NewLine);

      r.AppendFormat("Threads per Core: {0}{1}", cpuid[0].Length,

        Environment.NewLine);

      r.AppendLine(string.Format(CultureInfo.InvariantCulture,

        "Timer Frequency: {0} MHz", Stopwatch.Frequency * 1e-6));

      r.AppendLine("Time Stamp Counter: " + (hasTimeStampCounter ? (

        isInvariantTimeStampCounter ? "Invariant" : "Not Invariant") : "None"));

      r.AppendLine(string.Format(CultureInfo.InvariantCulture,

        "Estimated Time Stamp Counter Frequency: {0} MHz",

        Math.Round(estimatedTimeStampCounterFrequency * 100) * 0.01));

      r.AppendLine(string.Format(CultureInfo.InvariantCulture,

        "Estimated Time Stamp Counter Frequency Error: {0} Mhz",

        Math.Round(estimatedTimeStampCounterFrequency *

        estimatedTimeStampCounterFrequencyError * 1e5) * 1e-5));

      r.AppendLine(string.Format(CultureInfo.InvariantCulture,

        "Time Stamp Counter Frequency: {0} MHz",

        Math.Round(timeStampCounterFrequency * 100) * 0.01));   

      r.AppendLine();

      uint[] msrArray = GetMSRs();

      if (msrArray != null && msrArray.Length > 0) {

        for (int i = 0; i < cpuid.Length; i++) {

          r.AppendLine("MSR Core #" + (i + 1));

          r.AppendLine();

          r.AppendLine(" MSR       EDX       EAX");

          foreach (uint msr in msrArray)

            AppendMSRData(r, msr, cpuid[i][0].Thread);

          r.AppendLine();

        }

      }

      return r.ToString();

    }

    public override HardwareType HardwareType {

      get { return HardwareType.CPU; }

    }

    public bool HasModelSpecificRegisters {

      get { return hasModelSpecificRegisters; }

    }

    public bool HasTimeStampCounter {

      get { return hasTimeStampCounter; }

    }

    public double TimeStampCounterFrequency {

      get { return timeStampCounterFrequency; }

    }

    public override void Update() {

      if (hasTimeStampCounter && isInvariantTimeStampCounter) {

        // make sure always the same thread is used

        ulong mask = ThreadAffinity.Set(1UL << cpuid[0][0].Thread);

        // read time before and after getting the TSC to estimate the error

        long firstTime = Stopwatch.GetTimestamp();

        ulong timeStampCount = Opcode.Rdtsc();

        long time = Stopwatch.GetTimestamp();

        // restore the thread affinity mask

        ThreadAffinity.Set(mask);

        double delta = ((double)(time - lastTime)) / Stopwatch.Frequency;

        double error = ((double)(time - firstTime)) / Stopwatch.Frequency;

        // only use data if they are measured accuarte enough (max 0.1ms delay)

        if (error < 0.0001) {

          // ignore the first reading because there are no initial values 

          // ignore readings with too large or too small time window

          if (lastTime != 0 && delta > 0.5 && delta < 2) {

            // update the TSC frequency with the new value

            timeStampCounterFrequency =

              (timeStampCount - lastTimeStampCount) / (1e6 * delta);

          }

          lastTimeStampCount = timeStampCount;

          lastTime = time;

        }        

      }

      if (cpuLoad.IsAvailable) {

        cpuLoad.Update();

        for (int i = 0; i < coreLoads.Length; i++)

          coreLoads[i].Value = cpuLoad.GetCoreLoad(i);

        if (totalLoad != null)

          totalLoad.Value = cpuLoad.GetTotalLoad();

      }

    }

  }

}