#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2015 Joseph Helm and 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.IO;

namespace HeuristicLab.Problems.Instances.BinPacking {
  public class BPPORLIBParser {
    public string Name { get; set; }
    public string Description { get; set; }
    public int Items { get; set; }
    public int[] BinMeasures { get; set; }
    public int[][] ItemMeasures { get; set; }

    public BPPORLIBParser() {
      Reset();
    }

    public void Reset() {
      Name = Description = String.Empty;
      Items = 0;
      BinMeasures = null;
      ItemMeasures = null;
    }

    public void Parse(string file) {
      using (Stream stream = new FileStream(file, FileMode.Open, FileAccess.Read)) {
        Parse(stream);
      }
    }

    public void Export(string file) {
      using (Stream stream = new FileStream(file, FileMode.Open, FileAccess.Read)) {
        Export(stream);
      }
    }

    /// <summary>
    /// Reads from the given stream data which is expected to be in the BPP ORLIB format.
    /// </summary>
    /// <remarks>
    /// The stream is not closed or disposed. The caller has to take care of that.
    /// </remarks>
    /// <param name="stream">The stream to read data from.</param>
    /// <returns>True if the file was successfully read or false otherwise.</returns>
    public void Parse(Stream stream) {
      var reader = new StreamReader(stream);    
      var delim = new char[] { ' ', '\t' };     
      var problemClass = reader.ReadLine().Split(delim, StringSplitOptions.RemoveEmptyEntries);

      var nrOfItems = reader.ReadLine().Split(delim, StringSplitOptions.RemoveEmptyEntries);
      Items = int.Parse(nrOfItems[0]);
      //Numbering of instances..
      reader.ReadLine();
      var binMeasures = reader.ReadLine().Split(delim, StringSplitOptions.RemoveEmptyEntries);
      int depth;
      bool isThreeDimensional = false;
      if (int.TryParse(binMeasures[2], out depth)) {
        isThreeDimensional = true;
        BinMeasures = new int[3];
        BinMeasures[0] = int.Parse(binMeasures[0]);
        BinMeasures[1] = int.Parse(binMeasures[1]);
        BinMeasures[2] = depth;
      } else {
        BinMeasures = new int[2];
        BinMeasures[0] = int.Parse(binMeasures[0]);
        BinMeasures[1] = int.Parse(binMeasures[1]);
      }
      ItemMeasures = new int[Items][];

      for (int k = 0; k < Items; k++) {
        if (reader.EndOfStream) throw new InvalidDataException("Unexpected End of Stream (at line " + k + ").");
        var valLine = reader.ReadLine();
        while (String.IsNullOrWhiteSpace(valLine)) valLine = reader.ReadLine();
        var vals = valLine.Split(delim, StringSplitOptions.RemoveEmptyEntries);
        ItemMeasures[k] = new int[isThreeDimensional ? 3 : 2];
        ItemMeasures[k][0] = int.Parse(vals[0]);
        ItemMeasures[k][1] = int.Parse(vals[1]);
        if (isThreeDimensional)
          ItemMeasures[k][2] = int.Parse(vals[2]);
      }

      Int32 problemClassNr = -1;
      if (int.TryParse(problemClass[0], out problemClassNr)) {
        Name = (isThreeDimensional ? "3" : "2") + "dbpp_class_0" + problemClassNr;
        if (!isThreeDimensional) {
          if (problemClassNr >= 1 && problemClassNr <= 5)
            Description = "Proposed by Berkey and Wang.";
          else if (problemClassNr >= 6 && problemClassNr <= 10)
            Description = "Proposed by Martello and Vigo.";
        } else {
          if (problemClassNr >= 1 && problemClassNr <= 5)
            Description = "Proposed by Martello and Vigo.";
          else if (problemClassNr >= 6 && problemClassNr <= 9)
            Description = "Proposed by Berkey and Wang.";
        }
      } else {
        Name = "Unknown";
        Description = "<Missing>";
      }
      

    }

    public void Export(Stream stream) {
      bool isThreeDimensional = BinMeasures.Length == 3;
      var nameParts = Name.Split('_');
      int problemClassNr = int.Parse(nameParts[2]);

      var writer = new StreamWriter(stream);
      writer.WriteLine(String.Format("{0,-5}               PROBLEM CLASS ({1})", problemClassNr, Description));
      writer.WriteLine(String.Format("{0,-5} {1,-5} {2,-5}   WBIN,HBIN,DBIN", BinMeasures[0], BinMeasures[1], BinMeasures[2]));
      for (int i = 0; i < Items; i++) {
        if (i == 0)
          writer.WriteLine("{0,-5} {1,-5} {2,-5}   W(I),H(I),D(I),I=1,...,N", ItemMeasures[i][0], ItemMeasures[i][1], ItemMeasures[i][2]);
        else
          writer.WriteLine("{0,-5} {1,-5} {2,-5}", ItemMeasures[i][0], ItemMeasures[i][1], ItemMeasures[i][2]);
      }
      writer.Flush();
    }

  }
}