/*
 * Unpack -- a completely non-object oriented utility...
 *
 */

import java.io.*;

class Unpack
{
	static final int IDPAKHEADER= (('K' << 24) + ('C' << 16) + ('A' << 8) + 'P');

	static int intSwap(int i)
	{
		int a, b, c, d;

		a= i & 255;
		b= (i >> 8) & 255;
		c= (i >> 16) & 255;
		d= (i >> 24) & 255;

		return (a << 24) + (b << 16) + (c << 8) + d;
	}

	static boolean patternMatch(String pattern, String s)
	{
		int index;
		int remaining;

		if (pattern.equals(s))
		{
			return true;
		}

		// fairly lame single wildcard matching
		index= pattern.indexOf('*');
		if (index == -1)
		{
			return false;
		}
		if (!pattern.regionMatches(0, s, 0, index))
		{
			return false;
		}

		index += 1; // skip the *
		remaining= pattern.length() - index;
		if (s.length() < remaining)
		{
			return false;
		}

		if (!pattern.regionMatches(index, s, s.length() - remaining, remaining))
		{
			return false;
		}

		return true;
	}

	static void usage()
	{
		System.out.println("Usage: unpack <packfile> <match> <basedir>");
		System.out.println("   or: unpack -list <packfile>");
		System.out.println("<match> may contain a single * wildcard");
		System.exit(1);
	}

	public static void main(String[] args)
	{
		int ident;
		int dirofs;
		int dirlen;
		int i;
		int numLumps;
		byte[] name= new byte[56];
		String nameString;
		int filepos;
		int filelen;
		RandomAccessFile readLump;
		DataInputStream directory;
		String pakName;
		String pattern;

		if (args.length == 2)
		{
			if (!args[0].equals("-list"))
			{
				usage();
			}
			pakName= args[1];
			pattern= null;
		}
		else if (args.length == 3)
		{
			pakName= args[0];
			pattern= args[1];
		}
		else
		{
			pakName= null;
			pattern= null;
			usage();
		}

		try
		{
			// one stream to read the directory
			directory= new DataInputStream(new FileInputStream(pakName));

			// another to read lumps
			readLump= new RandomAccessFile(pakName, "r");

			// read the header
			ident= intSwap(directory.readInt());
			dirofs= intSwap(directory.readInt());
			dirlen= intSwap(directory.readInt());

			if (ident != IDPAKHEADER)
			{
				System.out.println(pakName + " is not a pakfile.");
				System.exit(1);
			}

			// read the directory
			directory.skipBytes(dirofs - 12);
			numLumps= dirlen / 64;

			System.out.println(numLumps + " lumps in " + pakName);

			for (i= 0; i < numLumps; i++)
			{
				directory.readFully(name);
				filepos= intSwap(directory.readInt());
				filelen= intSwap(directory.readInt());

				nameString= new String(name);
				// chop to the first 0 byte
				nameString= nameString.substring(0, nameString.indexOf(0));

				if (pattern == null)
				{
					// listing mode
					System.out.println(nameString + " : " + filelen + "bytes");
				}
				else if (patternMatch(pattern, nameString))
				{
					File writeFile;
					DataOutputStream writeLump;
					byte[] buffer= new byte[filelen];
					StringBuffer fixedString;
					String finalName;
					int index;

					System.out.println("Unpaking " + nameString + " " + filelen + " bytes");

					// load the lump
					readLump.seek(filepos);
					readLump.readFully(buffer);

					// quake uses forward slashes, but java requires
					// they only by the host's seperator, which
					// varies from win to unix
					fixedString= new StringBuffer(args[2] + File.separator + nameString);
					for (index= 0; index < fixedString.length(); index++)
					{
						if (fixedString.charAt(index) == '/')
						{
							fixedString.setCharAt(index, File.separatorChar);
						}
					}
					finalName= fixedString.toString();

					index= finalName.lastIndexOf(File.separatorChar);
					if (index != -1)
					{
						String finalPath;
						File writePath;

						finalPath= finalName.substring(0, index);
						writePath= new File(finalPath);
						writePath.mkdirs();
					}

					writeFile= new File(finalName);
					writeLump= new DataOutputStream(new FileOutputStream(writeFile));
					writeLump.write(buffer);
					writeLump.close();

				}
			}

			readLump.close();
			directory.close();

		}
		catch (IOException e)
		{
			System.out.println(e.toString());
		}
	}

}