/**
 * Copyright (C) 2013 Premium Minds.
 *
 * This file is part of billy spain (ES Pack).
 *
 * billy spain (ES Pack) is free software: you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation, either version 3 of the License, or (at your option) any
 * later version.
 *
 * billy spain (ES Pack) is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 * A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
 * details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with billy spain (ES Pack). If not, see <http://www.gnu.org/licenses/>.
 */
package com.premiumminds.billy.spain.util;

import java.io.IOException;
import java.io.InputStream;
import java.io.StringReader;
import java.security.KeyPair;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Security;

import org.apache.commons.io.IOUtils;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.openssl.PEMReader;

/**
 * Generates {@link PrivateKey} and {@link PublicKey}.
 */
public class KeyGenerator {

	private String	privateKeyPath;

	/**
	 * Generates the {@link PrivateKey} and {@link PublicKey} based on the
	 * {@link PrivateKey} location.
	 * 
	 * @param privateKeyPath
	 */
	public KeyGenerator(String privateKeyPath) {
		if (Security.getProvider("BC") == null) {
			Security.addProvider(new BouncyCastleProvider());
		}
		this.privateKeyPath = privateKeyPath;
	}

	private String getKeyFromFile() {
		InputStream inputStream = null;
		String key = "";

		try {
			inputStream = this.getClass().getResourceAsStream(privateKeyPath);
			key = IOUtils.toString(inputStream);
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			IOUtils.closeQuietly(inputStream);
		}

		return key;
	}

	private KeyPair getKeyPair() {
		PEMReader pemReader = new PEMReader(new StringReader(
				this.getKeyFromFile()));
		KeyPair pair = null;

		try {
			pair = (KeyPair) pemReader.readObject();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			IOUtils.closeQuietly(pemReader);
		}

		return pair;
	}

	/**
	 * @return {@link PrivateKey}
	 */
	public PrivateKey getPrivateKey() {
		return this.getKeyPair().getPrivate();
	}

	/**
	 * @return {@link PublicKey}
	 */
	public PublicKey getPublicKey() {
		return this.getKeyPair().getPublic();
	}

}