package org.openslx.satellitedaemon;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;
import java.nio.charset.StandardCharsets;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.InvalidKeySpecException;
import java.util.Properties;

import org.apache.log4j.Logger;
import org.openslx.satellitedaemon.util.Util;

public class Identity
{
	private static Logger log = Logger.getLogger( Identity.class );
	private static final Properties properties = new Properties();

	private static AsymKeyHolder akh = null;

	public static String getOrganizationName()
	{
		return properties.getProperty( "ORGANIZATION_NAME" );
	}

	private static BigInteger getModulus()
	{
		return toBigInt( properties.getProperty( "MODULUS" ) );
	}

	private static BigInteger getPublicExponent()
	{
		return toBigInt( properties.getProperty( "PUBLIC_EXPONENT" ) );
	}

	private static BigInteger getPrivateExponent()
	{
		return toBigInt( properties.getProperty( "PRIVATE_EXPONENT" ) );
	}

	/**
	 * Load properties
	 */
	static {
		InputStreamReader stream = null;
		try {
			// Load all entries of the config file into properties
			stream = new InputStreamReader(
					new FileInputStream( "config/identity.properties" ), StandardCharsets.UTF_8 );
			properties.load( stream );
			stream.close();
		} catch ( IOException e ) {
			log.error( "Could not load identity.properties. Exiting." );
			System.exit( 2 );
		} finally {
			Util.streamClose( stream );
		}

		Util.notNullOrEmptyFatal( getOrganizationName(), "Organiziation Name must not be empty!" );
		try {
			akh = new AsymKeyHolder( getPrivateExponent(), getPublicExponent(), getModulus() );
		} catch ( InvalidKeySpecException e ) {
			log.error( "InvalidKeySpecException", e );
		} catch ( NoSuchAlgorithmException e ) {
			log.error( "NoSuchAlgorithmException", e );
		}
	}

	/**
	 * Get private key for this server. If none exists yet, create a new one.
	 * 
	 * @return
	 */
	public static PrivateKey getPrivateKey()
	{
		if ( akh != null ) {
			return akh.getPrivateKey();
		}
		akh = new AsymKeyHolder();
		return akh.getPrivateKey();
	}

	/**
	 * Get public key for this server. If none exists yet, create a new one.
	 * 
	 * @return
	 */
	public static PublicKey getPublicKey()
	{
		if ( akh != null )
			return akh.getPublicKey();
		akh = new AsymKeyHolder();
		return akh.getPublicKey();
	}

	public static int keySize() {
		if (getModulus() != null) 
			return getModulus().bitLength();
		return -1;
	}
	
	private static BigInteger toBigInt( String str )
	{
		try {
			return new BigInteger( str );
		} catch ( Exception e ) {
			return null;
		}
	}
}