using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Text;

public class Images {
	private List<byte[]> images = new List<byte[]>();
	private Dictionary<string, int> refs = new Dictionary<string, int>();

	public Images(Stream s) {
		ExtractTar(Decompress(s));
	}

	private DeflateStream Decompress(Stream s) {
		return new DeflateStream(s, CompressionMode.Decompress);
	}

	private void ExtractTar(Stream stream) {
		var buffer = new byte[100];
		while (true) {
			stream.Read(buffer, 0, 100);
			var name = Encoding.ASCII.GetString(buffer).Trim('\0');
			if (String.IsNullOrWhiteSpace(name))
				break;
			stream.Seek(24, SeekOrigin.Current);
			stream.Read(buffer, 0, 12);
			var size = Convert.ToInt64(Encoding.ASCII.GetString(buffer, 0, 12).Trim(), 8);

			stream.Seek(376L, SeekOrigin.Current);

			var buf = new byte[size];
			stream.Read(buf, 0, buf.Length);
			if (name.EndsWith(".ref.txt")) {
				string r = Encoding.UTF8.GetString(buf).Trim('\0');
				refs.Add(name.Replace(".ref.txt", ".png"), refs[r]);
			}else{
				int i = images.Count;
				images.Add(buf);
				refs.Add(name, i);
			}

			var pos = stream.Position;

			var offset = 512 - (pos % 512);
			if (offset == 512)
				offset = 0;

			stream.Seek(offset, SeekOrigin.Current);
		}
	}

	public byte[] GetImage(string name) {
		return images[refs[name]];
	}

}