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using System;
using System.Drawing;
using System.IO;
using System.Text;

namespace Cyotek.Windows.Forms
{
  // Cyotek Color Picker controls library
  // Copyright © 2013 Cyotek. All Rights Reserved.
  // http://cyotek.com/blog/tag/colorpicker

  // If you use this code in your applications, donations or attribution are welcome

  /// <summary>
  /// Serializes and deserializes color palettes into and from the Gimp palette format.
  /// </summary>
  public class GimpPaletteSerializer : PaletteSerializer
  {
    #region Overridden Members

    /// <summary>
    /// Deserializes the <see cref="ColorCollection" /> contained by the specified <see cref="Stream" />.
    /// </summary>
    /// <param name="stream">The <see cref="Stream" /> that contains the palette to deserialize.</param>
    /// <returns>The <see cref="ColorCollection" /> being deserialized..</returns>
    public override ColorCollection Deserialize(Stream stream)
    {
      ColorCollection results;

      if (stream == null)
        throw new ArgumentNullException("stream");

      results = new ColorCollection();

      using (StreamReader reader = new StreamReader(stream))
      {
        string header;
        string startHeader;

        // check signature
        header = reader.ReadLine();
        startHeader = reader.ReadLine();

        if (header != "GIMP Palette")
          throw new InvalidDataException("Invalid palette file");

        while (startHeader != "#")
          startHeader = reader.ReadLine();

        while (!reader.EndOfStream)
        {
          int r;
          int g;
          int b;
          string data;
          string[] parts;

          data = reader.ReadLine();
          parts = !string.IsNullOrEmpty(data) ? data.Split(new[]
          {
            ' ', '\t'
          }, StringSplitOptions.RemoveEmptyEntries) : new string[0];

          if (!int.TryParse(parts[0], out r) || !int.TryParse(parts[1], out g) || !int.TryParse(parts[2], out b))
            throw new InvalidDataException(string.Format("Invalid palette contents found with data '{0}'", data));

          results.Add(Color.FromArgb(r, g, b));
        }
      }

      return results;
    }

    /// <summary>
    /// Serializes the specified <see cref="ColorCollection" /> and writes the palette to a file using the specified <see cref="Stream" />.
    /// </summary>
    /// <param name="stream">The <see cref="Stream" /> used to write the palette.</param>
    /// <param name="palette">The <see cref="ColorCollection" /> to serialize.</param>
    public override void Serialize(Stream stream, ColorCollection palette)
    {
      if (stream == null)
        throw new ArgumentNullException("stream");

      if (palette == null)
        throw new ArgumentNullException("palette");

      // TODO: Allow name and columns attributes to be specified

      using (StreamWriter writer = new StreamWriter(stream, Encoding.UTF8))
      {
        writer.WriteLine("GIMP Palette");
        writer.WriteLine("Name: ");
        writer.WriteLine("Columns: 8");
        writer.WriteLine("#");
        foreach (Color color in palette)
        {
          writer.Write("{0,-3} ", color.R);
          writer.Write("{0,-3} ", color.G);
          writer.Write("{0,-3} ", color.B);
          if (color.IsNamedColor)
            writer.Write(color.Name);
          else
            writer.Write("#{0:X2}{1:X2}{2:X2}", color.R, color.G, color.B);
          writer.WriteLine();
        }
      }
    }

    #endregion
  }
}