import java.util.*;
import java.io.*;


/**
 * A class that implements PGP interface for Java.
 * <P>
 * It calls gpg (GnuPG) program to do all the PGP processing.
 * $Id:$
 *
 * @author	Yaniv Yemini, January 2004.
 * @author	Please include this text with any copy of this code.
 * @author	.
 * @author	License: GPL v3
 * @author	Latest version of this code can be found at:
 * @author	http://www.macnews.co.il/mageworks/java/gnupg/
 * @author	.
 * @author	Based on a class GnuPG by John Anderson, which can be found
 * @author	at: http://lists.gnupg.org/pipermail/gnupg-devel/2002-February/018098.html
 * @version	0.5
 * @see		GnuPG - http://www.gnupg.org/
 */
public class GnuPG {
	
	// Konstants:
	private final String kGnuPGCommand = "/usr/local/bin/gpg --batch --armor --output -";
	
	// Class vars:
	private File	tmpFile;
	private int		gpg_exitCode = -1;
	private String	gpg_result;
	private String	gpg_err;
	
	
	/**
	 * Reads an output stream from an external process.
	 * Imeplemented as a thred.
	 */
	class ProcessStreamReader
	extends Thread
	{
		StringBuffer		stream;
		InputStreamReader	in;
		
		final static int BUFFER_SIZE = 1024;
		
		/**
		 *	Creates new ProcessStreamReader object.
		 *	
		 *	@param	in
		 */
		ProcessStreamReader (InputStream in)
		{
			super();
			
			this.in = new InputStreamReader(in);

			this.stream = new StringBuffer();
		}
		
		public void run()
		{
			try
			{       
				int read;
				char[] c = new char[BUFFER_SIZE];
				
				while ((read = in.read(c, 0, BUFFER_SIZE - 1)) > 0)
				{
					stream.append(c, 0, read);
					if (read < BUFFER_SIZE - 1) break;
				}
			}
			catch(IOException io) {}
		}
		
		String getString()
		{
				return stream.toString();
		}
	}
	
	
	/**
	 * Sign
	 *
	 * @param	inStr		input string to sign
	 * @param	passPhrase	passphrase for the personal private key to sign with
	 * @return				true upon success
	 */
	public boolean sign (String inStr, String passPhrase)
	{
		boolean		success;
		
		success = createTempFile (inStr);
		
		if (success)
		{
			success = runGnuPG ("--passphrase-fd 0 --sign " + this.tmpFile.getAbsolutePath (), passPhrase);
			this.tmpFile.delete ();
			if (success && this.gpg_exitCode != 0)
				success = false;
		}
		return success;
	}
	
	
	/**
	 * ClearSign
	 *
	 * @param	inStr		input string to sign
	 * @param	passPhrase	passphrase for the personal private key to sign with
	 * @return				true upon success
	 */
	public boolean clearSign (String inStr, String passPhrase)
	{
		boolean		success;
		
		success = createTempFile (inStr);
		
		if (success)
		{
			success = runGnuPG ("--passphrase-fd 0 --clearsign " + this.tmpFile.getAbsolutePath (), passPhrase);
			this.tmpFile.delete ();
			if (success && this.gpg_exitCode != 0)
				success = false;
		}
		return success;
	}
	
	
	/**
	 * Signs and encrypts a string
	 *
	 * @param	inStr		input string to encrypt
	 * @param	keyID		key ID of the key in GnuPG's key database to encrypt with
	 * @param	passPhrase	passphrase for the personal private key to sign with
	 * @return				true upon success
	 */
	public boolean signAndEncrypt (String inStr, String keyID, String passPhrase)
	{
		boolean		success;
		
		success = createTempFile (inStr);
		
		if (success)
		{
			success = runGnuPG ("--passphrase-fd 0 -se " + this.tmpFile.getAbsolutePath (), passPhrase);
			this.tmpFile.delete ();
			if (success && this.gpg_exitCode != 0)
				success = false;
		}
		return success;
	}
	
	
	/**
	 * Encrypt
	 *
	 * @param	inStr		input string to encrypt
	 * @param	keyID		key ID of the key in GnuPG's key database to encrypt with
	 * @return				true upon success
	 */
	public boolean encrypt (String inStr, String keyID)
	{
		boolean		success;
		
		success = runGnuPG ("-r " + keyID + " --encrypt", inStr);
		if (success && this.gpg_exitCode != 0)
			success = false;
		return success;
	}
	
	
	/**
	 * Decrypt
	 *
	 * @param	inStr		input string to decrypt
	 * @param	passPhrase	passphrase for the personal private key to sign with
	 * @return				true upon success
	 */
	public boolean decrypt (String inStr, String passPhrase)
	{
		boolean		success;
		
		success = createTempFile (inStr);
		
		if (success)
		{
			success = runGnuPG ("--passphrase-fd 0 --decrypt " + this.tmpFile.getAbsolutePath (), passPhrase);
			this.tmpFile.delete ();
			if (success && this.gpg_exitCode != 0)
				success = false;
		}
		return success;
	}
	
	
	/**
	 * Verify a signature
	 *
	 * @param	inStr	signature to verify
	 * @param	keyID	key ID of the key in GnuPG's key database
	 * @return			true if verified.
	 */
	/*
	public boolean verifySignature (String inStr, String keyID)
	{
		boolean		success;
		
		success = runGnuPG ("--sign " + keyID, inStr);
		if (success && this.gpg_exitCode != 0)
			success = false;
		return success;
	}
	*/
	
	/**
	 * Get processing result
	 *
	 * @return			result string.
	 */
	public String getResult ()
	{
		return gpg_result;
	}
	
	
	/**
	 * Get error output from GnuPG process
	 *
	 * @return			error string.
	 */
	public String getErrorString ()
	{
		return gpg_err;
	}
	
	
	/**
	 * Get GnuPG exit code
	 *
	 * @return			exit code.
	 */
	public int getExitCode ()
	{
		return gpg_exitCode;
	}
	
	
	/**
	 * Runs GnuPG external program
	 *
	 * @param	commandArgs	command line arguments
	 * @param	inputStr	key ID of the key in GnuPG's key database
	 * @return				true if success.
	 */
	private boolean runGnuPG (String commandArgs, String inputStr)
	{
		Process		p;
		String		fullCommand = kGnuPGCommand + " " + commandArgs;
//		String		fullCommand = commandArgs;
		
		System.out.println (fullCommand);
		
		try
		{
			p = Runtime.getRuntime().exec(fullCommand);
		}
		catch(IOException io)
		{
			System.out.println ("io Error" + io.getMessage ());
			return false;
		}
		
		ProcessStreamReader psr_stdout = new ProcessStreamReader(p.getInputStream());
		ProcessStreamReader psr_stderr = new ProcessStreamReader(p.getErrorStream());
		psr_stdout.start();
		psr_stderr.start();
		if (inputStr != null)
		{
			BufferedWriter out = new BufferedWriter(new OutputStreamWriter(p.getOutputStream()));
			try
			{
				out.write(inputStr);
				out.close();
			}
			catch(IOException io)
			{
				System.out.println("Exception at write! " + io.getMessage ());
				return false;
			}
		}
		
		try
		{
			p.waitFor();
			
			psr_stdout.join();
			psr_stderr.join();
		}
		catch(InterruptedException i)
		{
			System.out.println("Exception at waitfor! " + i.getMessage ());
			return false;
		}
		
		try
		{
			gpg_exitCode = p.exitValue ();
		}
		catch (IllegalThreadStateException itse)
		{
			return false;
		}
		
		gpg_result = psr_stdout.getString();
		gpg_err = psr_stdout.getString();
		
		return true;
	}
	
	
	/**
	 * A utility method for creating a unique temporary file when needed by one of
	 * the main methods.<BR>
	 * The file handle is store in tmpFile object var.
	 *
	 * @param	inStr	data to write into the file.
	 * @return			true if success
	 */
	private boolean createTempFile (String inStr)
	{
		this.tmpFile = null;
		FileWriter	fw;
		
		try
		{
			this.tmpFile = File.createTempFile ("YGnuPG", null);
		}
		catch (Exception e)
		{
			System.out.println("Cannot create temp file " + e.getMessage ());
			return false;
		}
		
		try
		{
			fw = new FileWriter (this.tmpFile);
			fw.write (inStr);
			fw.flush ();
			fw.close ();
		}
		catch (Exception e)
		{
			// delete our file:
			tmpFile.delete ();
			
			System.out.println("Cannot write temp file " + e.getMessage ());
			return false;
		}
		
		return true;
	}
	
	/*
    public static void main (String args[])
	{
        // use this to check:
        System.out.println("Hello World!");
		GnuPG pgp = new GnuPG ();
		if (args[0].equals ("sign"))
			pgp.sign (args[1], args[2]);
		else if (args[0].equals ("clearsign"))
			pgp.clearSign (args[1], args[2]);
		else if (args[0].equals ("se"))
			pgp.signAndEncrypt (args[1], args[2],args[3]);
		else if (args[0].equals ("encrypt"))
			pgp.encrypt (args[1], args[2]);
		else if (args[0].equals ("decrypt"))
			pgp.decrypt (args[1], args[2]);
		System.out.println("result: " + pgp.gpg_result + "\n\n");
		System.out.println("error: " + pgp.gpg_err + "\n\n");
		System.out.println("exit: " + pgp.gpg_exitCode + "\n\n");
    }
	*/
}