#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2012 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.Reflection;
using System.Text.RegularExpressions;
using HeuristicLab.Problems.DataAnalysis;
using ICSharpCode.SharpZipLib.Zip;

namespace HeuristicLab.Problems.Instances.Classification {
  public abstract class ResourceClassificationInstanceProvider : ClassificationInstanceProvider {

    protected abstract string FileName { get; }

    public override IEnumerable<IDataDescriptor> GetDataDescriptors() {
      var solutionsArchiveName = GetResourceName(FileName + @"\.zip");
      if (!String.IsNullOrEmpty(solutionsArchiveName)) {
        using (var solutionsZipFile = new ZipInputStream(GetType().Assembly.GetManifestResourceStream(solutionsArchiveName))) {
          foreach (var entry in GetZipContents(solutionsZipFile).OrderBy(x => x))
            yield return new ResourceClassificationDataDescriptor(Path.GetFileNameWithoutExtension(entry), Description, entry);
        }
      }
    }

    public override ClassificationProblemData LoadData(IDataDescriptor id) {
      var descriptor = (ResourceClassificationDataDescriptor)id;

      ClassificationProblemData claData = LoadData(GetTempFileForResource(descriptor.ResourceName));
      claData.Name = descriptor.Name;
      claData.Description = descriptor.Description;

      return claData;
    }

    protected virtual string GetResourceName(string fileName) {
      return Assembly.GetExecutingAssembly().GetManifestResourceNames()
              .Where(x => Regex.Match(x, @".*\.Data\." + fileName).Success).SingleOrDefault();
    }

    protected IEnumerable<string> GetZipContents(ZipInputStream zipFile) {
      ZipEntry entry;
      while ((entry = zipFile.GetNextEntry()) != null) {
        yield return entry.Name;
      }
    }

    private string GetTempFileForResource(string resourceName) {
      var instanceArchiveName = GetResourceName(FileName + @"\.zip");
      using (var instancesZipFile = new ZipFile(GetType().Assembly.GetManifestResourceStream(instanceArchiveName))) {
        var entry = instancesZipFile.GetEntry(resourceName);
        string path = Path.GetTempFileName();
        using (var stream = instancesZipFile.GetInputStream(entry)) {
          WriteStreamToTempFile(stream, path);
        }
        return path;
      }
    }

    private void WriteStreamToTempFile(Stream stream, string path) {
      using (FileStream output = new FileStream(path, FileMode.Create, FileAccess.Write)) {
        int cnt = 0;
        byte[] buffer = new byte[32 * 1024];
        while ((cnt = stream.Read(buffer, 0, buffer.Length)) != 0)
          output.Write(buffer, 0, cnt);
      }
    }
  }
}