/*
 * SVM.NET Library
 * Copyright (C) 2008 Matthew Johnson
 * 
 * This program 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.
 * 
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */


using System;
using System.Collections.Generic;
using System.IO;

namespace SVM {
  /// <summary>
  /// Encapsulates a problem, or set of vectors which must be classified.
  /// </summary>
  [Serializable]
  public class Problem {
    private int _count;
    private double[] _Y;
    private Node[][] _X;
    private int _maxIndex;

    /// <summary>
    /// Constructor.
    /// </summary>
    /// <param name="count">Number of vectors</param>
    /// <param name="y">The class labels</param>
    /// <param name="x">Vector data.</param>
    /// <param name="maxIndex">Maximum index for a vector</param>
    public Problem(int count, double[] y, Node[][] x, int maxIndex) {
      _count = count;
      _Y = y;
      _X = x;
      _maxIndex = maxIndex;
    }
    /// <summary>
    /// Empty Constructor.  Nothing is initialized.
    /// </summary>
    public Problem() {
    }
    /// <summary>
    /// Number of vectors.
    /// </summary>
    public int Count {
      get {
        return _count;
      }
      set {
        _count = value;
      }
    }
    /// <summary>
    /// Class labels.
    /// </summary>
    public double[] Y {
      get {
        return _Y;
      }
      set {
        _Y = value;
      }
    }
    /// <summary>
    /// Vector data.
    /// </summary>
    public Node[][] X {
      get {
        return _X;
      }
      set {
        _X = value;
      }
    }
    /// <summary>
    /// Maximum index for a vector.
    /// </summary>
    public int MaxIndex {
      get {
        return _maxIndex;
      }
      set {
        _maxIndex = value;
      }
    }

    /// <summary>
    /// Reads a problem from a stream.
    /// </summary>
    /// <param name="stream">Stream to read from</param>
    /// <returns>The problem</returns>
    public static Problem Read(Stream stream) {
      TemporaryCulture.Start();

      StreamReader input = new StreamReader(stream);
      List<double> vy = new List<double>();
      List<Node[]> vx = new List<Node[]>();
      int max_index = 0;

      while (input.Peek() > -1) {
        string[] parts = input.ReadLine().Trim().Split();

        vy.Add(double.Parse(parts[0]));
        int m = parts.Length - 1;
        Node[] x = new Node[m];
        for (int j = 0; j < m; j++) {
          x[j] = new Node();
          string[] nodeParts = parts[j + 1].Split(':');
          x[j].Index = int.Parse(nodeParts[0]);
          x[j].Value = double.Parse(nodeParts[1]);
        }
        if (m > 0)
          max_index = Math.Max(max_index, x[m - 1].Index);
        vx.Add(x);
      }

      TemporaryCulture.Stop();

      return new Problem(vy.Count, vy.ToArray(), vx.ToArray(), max_index);
    }

    /// <summary>
    /// Writes a problem to a stream.
    /// </summary>
    /// <param name="stream">The stream to write the problem to.</param>
    /// <param name="problem">The problem to write.</param>
    public static void Write(Stream stream, Problem problem) {
      TemporaryCulture.Start();

      StreamWriter output = new StreamWriter(stream);
      for (int i = 0; i < problem.Count; i++) {
        output.Write(problem.Y[i]);
        for (int j = 0; j < problem.X[i].Length; j++)
          output.Write(" {0}:{1}", problem.X[i][j].Index, problem.X[i][j].Value);
        output.WriteLine();
      }
      output.Flush();

      TemporaryCulture.Stop();
    }

    /// <summary>
    /// Reads a Problem from a file.
    /// </summary>
    /// <param name="filename">The file to read from.</param>
    /// <returns>the Probem</returns>
    public static Problem Read(string filename) {
      FileStream input = File.OpenRead(filename);
      try {
        return Read(input);
      }
      finally {
        input.Close();
      }
    }

    /// <summary>
    /// Writes a problem to a file.   This will overwrite any previous data in the file.
    /// </summary>
    /// <param name="filename">The file to write to</param>
    /// <param name="problem">The problem to write</param>
    public static void Write(string filename, Problem problem) {
      FileStream output = File.Open(filename, FileMode.Create);
      try {
        Write(output, problem);
      }
      finally {
        output.Close();
      }
    }
  }
}