/*
 * Copyright (c) 2018 NTT DATA INTELLILINK Corporation. All rights reserved.
 *
 * Hinemos (http://www.hinemos.info/)
 *
 * See the LICENSE file for licensing information.
 */

package com.clustercontrol.commons.util;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class CryptUtil {
	
	private static final Log m_log = LogFactory.getLog( CryptUtil.class );
	
	// 使用する暗号化アルゴリズム
	private static String algorithm = "BLOWFISH";
	
	private static String cryptKey = "hinemos";
	
	static {
		String etcdir = System.getProperty("hinemos.manager.etc.dir");
		String keyFile = "db_crypt.key";
		String keyPath = etcdir + File.separator + keyFile;
		FileReader fileReader = null;
		BufferedReader bufferedReader = null;
		
		try {
			fileReader = new FileReader(keyPath);
			bufferedReader = new BufferedReader(fileReader);
			cryptKey = bufferedReader.readLine();
		} catch (Exception e){
			m_log.warn("file not readable. (" + keyFile + ") : " + e.getMessage(), e);
		} finally {
			try {
				if (bufferedReader != null) {
					bufferedReader.close();
				}
			} catch (IOException e) {
			}
			try {
				if (fileReader != null) {
					fileReader.close();
				}
			} catch (IOException e) {
			}
		}
		// m_log.info("key=[" + cryptKey + "]"); // TODO この行は、コメントアウトすること！（パスワードがログに出力されてしまうので。）
	}
	
	public static String encrypt(String word) {
		return encrypt(cryptKey, word);
	}
	
	private static String encrypt(String key, String word) {
		if (word == null) {
			return null;
		}
		// 暗号化
		SecretKeySpec sksSpec = new SecretKeySpec(key.getBytes(), algorithm);
		Cipher cipher = null;
		try {
			cipher = Cipher.getInstance(algorithm);
		} catch (NoSuchAlgorithmException | NoSuchPaddingException e) {
			m_log.warn("encrypt : " + (e.getClass().getName()) + "," + e.getMessage(), e);
			return null;
		}
		try {
			cipher.init(Cipher.ENCRYPT_MODE, sksSpec);
		} catch (InvalidKeyException e) {
			m_log.warn("encrypt : " + (e.getClass().getName()) + "," + e.getMessage(), e);
			return null;
		}
		
		byte[] encrypted = null;
		try {
			encrypted = cipher.doFinal(word.getBytes());
		} catch (IllegalBlockSizeException | BadPaddingException e) {
			m_log.warn("encrypt : " + (e.getClass().getName()) + "," + e.getMessage(), e);
			return null;
		}
		
		return Base64.encodeBase64String(encrypted);
	}

	public static String decrypt(String word) {
		return decrypt(cryptKey, word);
	}
	
	public static String decrypt(String key, String word) {
		if (word == null) {
			return null;
		}
		
		byte[] encrypted = Base64.decodeBase64(word);
		// 複合化
		SecretKeySpec sksSpec = new SecretKeySpec(key.getBytes(), algorithm);
		Cipher cipher = null;
		try {
			cipher = Cipher.getInstance(algorithm);
		} catch (NoSuchAlgorithmException | NoSuchPaddingException e) {
			m_log.warn("encrypt : " + (e.getClass().getName()) + "," + e.getMessage(), e);
			return null;
		}
		
		try {
			cipher.init(Cipher.DECRYPT_MODE, sksSpec);
		} catch (InvalidKeyException e) {
			m_log.warn("encrypt : " + (e.getClass().getName()) + "," + e.getMessage(), e);
			return null;
		}
		
		byte[] decrypted;
		try {
			decrypted = cipher.doFinal(encrypted);
		} catch (IllegalBlockSizeException | BadPaddingException e) {
			m_log.warn("encrypt : " + (e.getClass().getName()) + "," + e.getMessage(), e);
			return null;
		}
		
		return new String(decrypted);
	}
	
	/**
	 * バージョンアップツールから利用する
	 * @param args
	 */
	public static void main(String args[]) {
		if (args.length != 3) {
			System.out.println("usage CryptUtil encrypt <key> <word>");
			System.out.println("usage CryptUtil decrypt <key> <word>");
				System.exit(1);
		}
		String mode = args[0];
		String key = args[1];
		String word = args[2];
		// System.out.println("mode=" + mode + ", key=" + key + ", word=" + word);
		if ("decrypt".equals(mode)) {
		//	System.out.println("decrypt");
			System.out.println(decrypt(key, word));
		} else {
		//	System.out.println("encrypt");
			System.out.println(encrypt(key, word));
		}
	}
}