using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Optimization; 
using HeuristicLab.Parameters;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using HeuristicLab.Problems.DataAnalysis;     

namespace PGE {
  [Item(Name = "Priorizied Grammar Enumeration (PGE)", Description = "Priorizied grammar enumeration algorithm. Worm, T. and Chiu K., 'Prioritized Grammar Enumeration: Symbolic Regression by Dynamic Programming'. GECCO 2013")]

  [Creatable(Category = CreatableAttribute.Categories.Algorithms, Priority = 999)]

  [StorableClass] 
  public unsafe class PGE : BasicAlgorithm {

    [DllImport("go-pge.dll", EntryPoint = "addTestData", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]
    public static extern void AddTestData(IntPtr indepNames, IntPtr depndNames, IntPtr matrix, int nEntries);

    [DllImport("go-pge.dll", EntryPoint = "addTrainData", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]
    public static extern void AddTrainData(IntPtr indepNames, IntPtr depndNames, IntPtr matrix, int nEntries);

    [DllImport("go-pge.dll", EntryPoint = "initSearch", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]
    public static extern void InitSearch(int maxGen, int pgeRptEpoch, int pgeRptCount, int pgeArchiveCap, int peelCnt, int evalrCount, double zeroEpsilon, IntPtr initMethod, IntPtr growMethod, int sortType);

    [DllImport("go-pge.dll", EntryPoint = "initTreeParams", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]
    public static extern void InitTreeParams(IntPtr roots, IntPtr nodes, IntPtr nonTrig, IntPtr leafs, IntPtr usableVars, int numUsableVars, int maxSize, int minSize, int maxDepth, int minDepth);

    [DllImport("go-pge.dll", EntryPoint = "initProblem", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]
    public static extern void InitProblem(IntPtr name, int maxIter, double hitRatio, int searchVar, IntPtr ProblemTypeString, int numProcs);

    [DllImport("go-pge.dll", EntryPoint = "stepW", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]
    public static extern void StepW();

    [DllImport("go-pge.dll", EntryPoint = "getStepResult", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]
    public static extern IntPtr GetStepResult(out int noBestPush, out int bestNewMinErr, out int bestlen1, out int bestlen2, out int testscore, out int nCoeff);

    [DllImport("go-pge.dll", EntryPoint = "getCoeffResult", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)]
    public static extern double GetCoeffResult();

    public override Type ProblemType { get { return typeof(RegressionProblem); } }
    public new RegressionProblem Problem { get { return (RegressionProblem)base.Problem; } }

    #region parameter names
    private static readonly string MaxIterationsParameterName = "MaxIterations";                      
    private static readonly string MaxGenParameterName = "MaxGen";
    private static readonly string EvalrCountParameterName = "EvalrCount";
    private static readonly string MaxSizeParameterName = "MaxSize";
    private static readonly string MinSizeParameterName = "MinSize";
    private static readonly string MaxDepthParameterName = "MaxDepth";
    private static readonly string SearchVarParameterName = "SearchVar";
    private static readonly string MinDepthParameterName = "MinDepth";
    private static readonly string PgeRptEpochParameterName = "PgeRptEpoch";
    private static readonly string PgeRptCountParameterName = "PgeRptCount";
    private static readonly string PgeArchiveCapParameterName = "PgeArchiveCap";
    private static readonly string PeelCntParameterName = "PeelCnt";
    private static readonly string ZeroEpsilonParameterName = "ZeroEpsilon";
    private static readonly string HitRatioParameterName = "HitRatio";                
    private static readonly string InitMethodParameterName = "InitMethod";
    private static readonly string GrowMethodParameterName = "GrowMethod";
    private static readonly string RootsParameterName = "Roots";
    private static readonly string NodesParameterName = "Nodes";
    private static readonly string NonTrigParameterName = "NonTrig";
    private static readonly string LeafsParameterName = "Leafs";

    #endregion

    #region parameters                                            
    private IFixedValueParameter<IntValue> MaxIterationsParameter {
      get { return (IFixedValueParameter<IntValue>)Parameters[MaxIterationsParameterName]; }
    }
    public int MaxIterations {
      get { return MaxIterationsParameter.Value.Value; }
      set { MaxIterationsParameter.Value.Value = value; }
    }

    private IFixedValueParameter<IntValue> MaxGenParameter {
      get { return (IFixedValueParameter<IntValue>)Parameters[MaxGenParameterName]; }
    }
    public int MaxGen {
      get { return MaxGenParameter.Value.Value; }
      set { MaxGenParameter.Value.Value = value; }
    }

    private IFixedValueParameter<IntValue> EvalrCountParameter {
      get { return (IFixedValueParameter<IntValue>)Parameters[EvalrCountParameterName]; }
    }
    public int EvalrCount {
      get { return EvalrCountParameter.Value.Value; }
      set { EvalrCountParameter.Value.Value = value; }
    }

    private IFixedValueParameter<IntValue> MaxSizeParameter {
      get { return (IFixedValueParameter<IntValue>)Parameters[MaxSizeParameterName]; }
    }
    public int MaxSize {
      get { return MaxSizeParameter.Value.Value; }
      set { MaxSizeParameter.Value.Value = value; }
    }

    private IFixedValueParameter<IntValue> MinSizeParameter {
      get { return (IFixedValueParameter<IntValue>)Parameters[MinSizeParameterName]; }
    }
    public int MinSize {
      get { return MinSizeParameter.Value.Value; }
      set { MinSizeParameter.Value.Value = value; }
    }

    private IFixedValueParameter<IntValue> MaxDepthParameter {
      get { return (IFixedValueParameter<IntValue>)Parameters[MaxDepthParameterName]; }
    }
    public int MaxDepth {
      get { return MaxDepthParameter.Value.Value; }
      set { MaxDepthParameter.Value.Value = value; }
    }

    private IFixedValueParameter<IntValue> SearchVarParameter {
      get { return (IFixedValueParameter<IntValue>)Parameters[SearchVarParameterName]; }
    }
    public int SearchVar {
      get { return SearchVarParameter.Value.Value; }
      set { SearchVarParameter.Value.Value = value; }
    }

    private IFixedValueParameter<IntValue> MinDepthParameter {
      get { return (IFixedValueParameter<IntValue>)Parameters[MinDepthParameterName]; }
    }
    public int MinDepth {
      get { return MinDepthParameter.Value.Value; }
      set { MinDepthParameter.Value.Value = value; }
    }

    private IFixedValueParameter<IntValue> PgeRptEpochParameter {
      get { return (IFixedValueParameter<IntValue>)Parameters[PgeRptEpochParameterName]; }
    }
    public int PgeRptEpoch {
      get { return PgeRptEpochParameter.Value.Value; }
      set { PgeRptEpochParameter.Value.Value = value; }
    }

    private IFixedValueParameter<IntValue> PgeRptCountParameter {
      get { return (IFixedValueParameter<IntValue>)Parameters[PgeRptCountParameterName]; }
    }
    public int PgeRptCount {
      get { return PgeRptCountParameter.Value.Value; }
      set { PgeRptCountParameter.Value.Value = value; }
    }

    private IFixedValueParameter<IntValue> PgeArchiveCapParameter {
      get { return (IFixedValueParameter<IntValue>)Parameters[PgeArchiveCapParameterName]; }
    }
    public int PgeArchiveCap {
      get { return PgeArchiveCapParameter.Value.Value; }
      set { PgeArchiveCapParameter.Value.Value = value; }
    }

    private IFixedValueParameter<IntValue> PeelCntParameter {
      get { return (IFixedValueParameter<IntValue>)Parameters[PeelCntParameterName]; }
    }
    public int PeelCnt {
      get { return PeelCntParameter.Value.Value; }
      set { PeelCntParameter.Value.Value = value; }
    }

    private IFixedValueParameter<DoubleValue> ZeroEpsilonParameter {
      get { return (IFixedValueParameter<DoubleValue>)Parameters[ZeroEpsilonParameterName]; }
    }
    public double ZeroEpsilon {
      get { return ZeroEpsilonParameter.Value.Value; }
      set { ZeroEpsilonParameter.Value.Value = value; }
    }

    private IFixedValueParameter<DoubleValue> HitRatioParameter {
      get { return (IFixedValueParameter<DoubleValue>)Parameters[HitRatioParameterName]; }
    }
    public double HitRatio {
      get { return HitRatioParameter.Value.Value; }
      set { HitRatioParameter.Value.Value = value; }
    }

    private IFixedValueParameter<StringValue> InitMethodParameter {
      get { return (IFixedValueParameter<StringValue>)Parameters[InitMethodParameterName]; }
    }
    public string InitMethod {
      get { return InitMethodParameter.Value.Value; }
      set { InitMethodParameter.Value.Value = value; }
    }

    private IFixedValueParameter<StringValue> GrowMethodParameter {
      get { return (IFixedValueParameter<StringValue>)Parameters[GrowMethodParameterName]; }
    }
    public string GrowMethod {
      get { return GrowMethodParameter.Value.Value; }
      set { GrowMethodParameter.Value.Value = value; }
    }

    private IFixedValueParameter<StringValue> RootsParameter {
      get { return (IFixedValueParameter<StringValue>)Parameters[RootsParameterName]; }
    }
    public string Roots {
      get { return RootsParameter.Value.Value; }
      set { RootsParameter.Value.Value = value; }
    }

    private IFixedValueParameter<StringValue> NodesParameter {
      get { return (IFixedValueParameter<StringValue>)Parameters[NodesParameterName]; }
    }
    public string Nodes {
      get { return NodesParameter.Value.Value; }
      set { NodesParameter.Value.Value = value; }
    }

    private IFixedValueParameter<StringValue> NonTrigParameter {
      get { return (IFixedValueParameter<StringValue>)Parameters[NonTrigParameterName]; }
    }
    public string NonTrig {
      get { return NonTrigParameter.Value.Value; }
      set { NonTrigParameter.Value.Value = value; }
    }

    private IFixedValueParameter<StringValue> LeafsParameter {
      get { return (IFixedValueParameter<StringValue>)Parameters[LeafsParameterName]; }
    }
    public string Leafs {
      get { return LeafsParameter.Value.Value; }
      set { LeafsParameter.Value.Value = value; }
    }
    #endregion

    public PGE() {

      base.Problem = new RegressionProblem();

      // algorithm parameters are shown in the GUI
      Parameters.Add(new FixedValueParameter<IntValue>(MaxIterationsParameterName, new IntValue(50)));
      Parameters.Add(new FixedValueParameter<IntValue>(SearchVarParameterName, new IntValue(0)));
      Parameters.Add(new FixedValueParameter<IntValue>(MinDepthParameterName, new IntValue(1)));
      Parameters.Add(new FixedValueParameter<IntValue>(MaxDepthParameterName, new IntValue(6)));
      Parameters.Add(new FixedValueParameter<IntValue>(MinSizeParameterName, new IntValue(4)));
      Parameters.Add(new FixedValueParameter<IntValue>(MaxSizeParameterName, new IntValue(50)));
      Parameters.Add(new FixedValueParameter<IntValue>(EvalrCountParameterName, new IntValue(2)));
      Parameters.Add(new FixedValueParameter<IntValue>(PeelCntParameterName, new IntValue(3)));
      Parameters.Add(new FixedValueParameter<IntValue>(PgeArchiveCapParameterName, new IntValue(256)));
      Parameters.Add(new FixedValueParameter<IntValue>(PgeRptCountParameterName, new IntValue(20)));
      Parameters.Add(new FixedValueParameter<IntValue>(PgeRptEpochParameterName, new IntValue(1)));
      Parameters.Add(new FixedValueParameter<IntValue>(MaxGenParameterName, new IntValue(200)));               
                                                                                                                                     
      Parameters.Add(new FixedValueParameter<StringValue>(InitMethodParameterName, new StringValue("method1")));  // TODO Dropdown
      Parameters.Add(new FixedValueParameter<StringValue>(GrowMethodParameterName, new StringValue("method1")));

      Parameters.Add(new FixedValueParameter<StringValue>(RootsParameterName, new StringValue("Add")));    // TODO: checkeditemlist
      Parameters.Add(new FixedValueParameter<StringValue>(NodesParameterName, new StringValue("Add Mul")));  // TODO: checkeditemlist
      Parameters.Add(new FixedValueParameter<StringValue>(NonTrigParameterName, new StringValue("Add Mul"))); // TODO: checkeditemlist
      Parameters.Add(new FixedValueParameter<StringValue>(LeafsParameterName, new StringValue("Var ConstantF")));

      Parameters.Add(new FixedValueParameter<DoubleValue>(ZeroEpsilonParameterName, new DoubleValue(0.00001)));
      Parameters.Add(new FixedValueParameter<DoubleValue>(HitRatioParameterName, new DoubleValue(0.01)));
    }

 
    [StorableConstructor]
    public PGE(bool deserializing) : base(deserializing) { }

   
    public PGE(PGE original, Cloner cloner) : base(original, cloner) {    
      // nothing to clone
    }

    public override IDeepCloneable Clone(Cloner cloner) {
      return new PGE(this, cloner);
    }

    protected override void Run(CancellationToken cancellationToken) {

      // TODO: the following is potentially problematic for other go processes run on the same machine at the same time
      Environment.SetEnvironmentVariable("GOGC", "off");
      Environment.SetEnvironmentVariable("GODEBUG", "cgocheck=0");
      Environment.SetEnvironmentVariable("CGO_ENABLED", "1");



      //Constants
      int sortType = 0;
      string problemTypeString = "benchmark";
      int numProc = 12;
      string problemName = Problem.ProblemData.Name;


      var problemData = Problem.ProblemData;
      var variables = problemData.AllowedInputVariables.Concat(new string[] { problemData.TargetVariable });
      // no idea why the following are IntPtr, this should not be necessary for marshalling, it should be ok to just send the double[,]
      int nTrainData;
      int nTestData;
      IntPtr trainData = GetData(problemData.Dataset, variables, problemData.TrainingIndices, out nTrainData);
      IntPtr testData = GetData(problemData.Dataset, variables, problemData.TestIndices, out nTestData);

      var inputVariableNames = string.Join(" ", problemData.AllowedInputVariables); 
      // TODO: does this work when input variables contain spaces?
      // is split on the go side, just for simpler passing

      IntPtr cIndepNames = Marshal.StringToHGlobalAnsi(inputVariableNames);
      IntPtr cDependentNames = Marshal.StringToHGlobalAnsi(problemData.TargetVariable);
      // TODO: is it ok to use any variable here?
      // Dependent- and Independentnames are the variables from the test/train data, e.g. from "Korns_02.trn" dep: x y z v w  indep: f(xs)

      IntPtr cInitMethod = Marshal.StringToHGlobalAnsi(InitMethod);
      IntPtr cGrowMethod = Marshal.StringToHGlobalAnsi(GrowMethod);

      IntPtr cRoots = Marshal.StringToHGlobalAnsi(Roots);
      IntPtr cNodes = Marshal.StringToHGlobalAnsi(Nodes);
      IntPtr cNonTrig = Marshal.StringToHGlobalAnsi(NonTrig);
      IntPtr cLeafs = Marshal.StringToHGlobalAnsi(Leafs);

      IntPtr cName = Marshal.StringToHGlobalAnsi(problemName);
      IntPtr cProblemTypeString = Marshal.StringToHGlobalAnsi(problemTypeString);



      AddTestData(cIndepNames, cDependentNames, testData, nTestData);

      AddTrainData(cIndepNames, cDependentNames, trainData, nTrainData);

      int numberOfUseableVariables = problemData.AllowedInputVariables.Count();
      IntPtr cUseableVars = GetUsableVars(numberOfUseableVariables);

      InitSearch(MaxGen, PgeRptEpoch, PgeRptCount, PgeArchiveCap, PeelCnt, EvalrCount, ZeroEpsilon, cInitMethod, cGrowMethod, sortType);

      // cUsableVars: list of indices into dependent variables
      InitTreeParams(cRoots, cNodes, cNonTrig, cLeafs, cUseableVars, numberOfUseableVariables, MaxSize, MinSize, MaxDepth, MinDepth);

      // SearchVar: list of indices into independent variables (0 for first index)
      InitProblem(cName, MaxIterations, HitRatio, SearchVar, cProblemTypeString, numProc);

      var curItersItem = new IntValue();

      for (int iter = 1; iter <= MaxIterations; iter++) {
        curItersItem.Value = iter;

        StepW();  // TODO: alg crashes here

        for (int iPeel = 0; iPeel < PeelCnt; iPeel++) {
          int nobestpush = 0;       //bool
          int bestNewMinError = 0;  //bool
          int bestlen1 = 0; 
          int bestlen2 = 0;
          int nCoeff = 0;
          int testScore = 0;

          IntPtr eqn = GetStepResult(out nobestpush, out bestNewMinError, out bestlen1, out bestlen2, out testScore, out nCoeff);

          string eqnStr = Marshal.PtrToStringAnsi(eqn);

          if (nobestpush == 1) 
          {
            Console.WriteLine("No best push");
          } else {
            Console.WriteLine("Push/Pop (" + bestlen1 + "," + bestlen2 + ") " + eqnStr);

            StringBuilder sb = new StringBuilder("");
            for (int iCoeff = 0; iCoeff < nCoeff; iCoeff++) {
              double coeffVal = GetCoeffResult();
              Console.WriteLine("Coeff: " + coeffVal);
              sb.Append(coeffVal + "; ");
            }

            var curItersResult = new Result("Iteration " + iter + " " + iPeel, curItersItem);
            var coeffItersResult = new Result("Coeff " + iter + " " + iPeel, new StringValue(sb.ToString()));

            var bestQualityItem = new StringValue(eqnStr);
            var bestQualityResult = new Result("Best quality " + iter + " " + iPeel, bestQualityItem);
            Results.Add(curItersResult);
            Results.Add(coeffItersResult);
            Results.Add(bestQualityResult);
   
          }

        }

        if (cancellationToken.IsCancellationRequested) break;
      }

      Marshal.FreeHGlobal(cUseableVars);
      Marshal.FreeHGlobal(trainData);
      Marshal.FreeHGlobal(testData);
      // Results.Add(new Result("Execution time", new TimeSpanValue(this.ExecutionTime)));
    }

    public override bool SupportsPause {
      get { return false; }
    }

    private static IntPtr GetUsableVars(int n) {
      long[] vars = new long[n];

      for (int i = 0; i < n; i++) {
        vars[i] = i;
      }

      IntPtr usableVars = Marshal.AllocHGlobal(sizeof(long) * n);
      Marshal.Copy(vars, 0, usableVars, n);

      return usableVars;
    }

    private static IntPtr GetData(IDataset ds, IEnumerable<string> variableNames, IEnumerable<int> rows, out int n) {

      var dim = variableNames.Count();
      double[] val = new double[rows.Count() * dim];
      int r = 0;
      foreach(var row in rows) {
        int c = 0;
        foreach(var var in variableNames) {
          val[r * dim + c] = ds.GetDoubleValue(var, r);
          c++;
        }
        r++;
      }

      n = val.Length;

      // TODO: seems strange to marshal this explicitly, we can just send the data over to PGE
      IntPtr data = Marshal.AllocHGlobal(sizeof(double) * val.Length);
      Marshal.Copy(val, 0, data, val.Length);

      return data;
    }
  }
}