#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2018 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using HEAL.Attic;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Encodings.IntegerVectorEncoding;
using HeuristicLab.Encodings.RealVectorEncoding;
using HeuristicLab.Optimization;
using HeuristicLab.Parameters;

namespace HeuristicLab.Problems.Modifiers {
  [StorableType("FADAA1BF-7B7A-4E28-AA15-22AF56D63CFE")]
  [Item("MultiObjectiveEvaluationLogProblemModifier", "A problem modifier that logs evaluations in a file")]
  public class EvaluationLoggingProblemModifier : ProblemModifier {
    private readonly object fileLock = new object();
    #region ParameterNames
    private const string LogFileParameterName = "LogFile";
    #endregion

    #region Parameters
    public IValueParameter<FileValue> LogFileParameter => (IValueParameter<FileValue>)Parameters[LogFileParameterName];
    #endregion

    #region ParameterNames
    public FileValue LogFile => LogFileParameter.Value;
    #endregion

    #region Constructors & Cloning
    [StorableConstructor]
    protected EvaluationLoggingProblemModifier(StorableConstructorFlag _) : base(_) { }
    protected EvaluationLoggingProblemModifier(EvaluationLoggingProblemModifier original, Cloner cloner) : base(original, cloner) {
    }
    public EvaluationLoggingProblemModifier() {
      var defaultFileName = $"{Environment.CurrentDirectory}\\Log_{Guid.NewGuid()}.txt";
      var value = new FileValue();
      value.StringValue.Value = defaultFileName;
      Parameters.Add(new ValueParameter<FileValue>(LogFileParameterName, "The log file into which evaluations should be logged.", value));
    }
    [StorableHook(HookType.AfterDeserialization)]
    private void AfterDeserialization() { }
    public override IDeepCloneable Clone(Cloner cloner) {
      return new EvaluationLoggingProblemModifier(this, cloner);
    }
    #endregion

    #region ProblemModifier
    public override double[] ModifiedEvaluate(Individual individual, IRandom random) {
      var qualities = base.ModifiedEvaluate(individual, random);
      lock (fileLock) { LogResultsToFile(individual, LogFile.Value, Encoding); }
      return qualities;
    }
    #endregion

    #region Helpers
    private static void LogResultsToFile(Individual individual, string logFilePath, IEncoding enc) {
      if (string.IsNullOrEmpty(logFilePath)) throw new ArgumentException("Log path is null or empty");
      var logFile = new FileInfo(logFilePath);
      if (!logFile.Exists) {
        logFile.Directory?.Create();
        logFile.Create();
      }
      var logLines = new List<string>();
      var sb = new StringBuilder();
      var inputs = ExtractInputs(individual, enc).ToArray();
      var additionalInfo = ExtractAdditionalInfo(individual, enc);
      if (logFile.Length == 0) {
        var digits = Math.Ceiling(Math.Log10(inputs.Length));
        var header = Enumerable
          .Range(0, inputs.Length)
          .Select(x => string.Format($"X{{0:D{digits}}}", x))
          .Concat(additionalInfo.Select(x => x.Item1));
        logLines.Add(string.Join(";", header));
        sb.Clear();
      }
      logLines.Add(string.Join(";", inputs.Concat(additionalInfo.Select(x => x.Item2))));
      sb.Clear();
      File.AppendAllLines(logFilePath, logLines);
    }
    private static Tuple<string, string>[] ExtractAdditionalInfo(Individual individual, IEncoding enc) {
      return individual.Values.Where(x => x.Key != enc.Name).OrderBy(x => x.Key).Select(x => Tuple.Create(x.Key, x.Value.ToString())).ToArray();
    }
    private static IEnumerable<object> ExtractInputs(Individual individual, IEncoding encoding) {
      var encodingType = encoding.GetType();
      if (encodingType == typeof(IntegerVectorEncoding))
        return individual.IntegerVector().Select(x => (object)x);
      if (encodingType == typeof(RealVectorEncoding))
        return individual.RealVector().Select(x => (object)x);
      throw new ArgumentException("This input encoding is not supported yet");
    }
    #endregion
  }
}