// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.
package com.cloud.bridge.util;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Properties;

import org.apache.log4j.Logger;
import org.jasypt.encryption.pbe.StandardPBEStringEncryptor;
import org.jasypt.encryption.pbe.config.SimpleStringPBEConfig;


public class EncryptionSecretKeyCheckerUtil {
    private static final Logger s_logger = Logger.getLogger(EncryptionSecretKeyCheckerUtil.class);
    
    private static final String s_keyFile = "/etc/cloud/management/key";
    private static final String s_envKey = "CLOUD_SECRET_KEY";
    private static StandardPBEStringEncryptor s_encryptor = new StandardPBEStringEncryptor();
    private static boolean s_useEncryption = false;

    static{
        //Get encryption type from db.properties
        final File dbPropsFile = ConfigurationHelper.findConfigurationFile("db.properties");
        final Properties dbProps = new Properties();
        try {
            dbProps.load(new FileInputStream(dbPropsFile));

            final String encryptionType = dbProps.getProperty("db.cloud.encryption.type");
            
            s_logger.debug("Encryption Type: "+ encryptionType);

            if(encryptionType != null && !encryptionType.equals("none")){
                
                s_encryptor.setAlgorithm("PBEWithMD5AndDES");
                String secretKey = null;
                
                SimpleStringPBEConfig stringConfig = new SimpleStringPBEConfig(); 
                
                if(encryptionType.equals("file")){
                    try {
                        BufferedReader in = new BufferedReader(new FileReader(s_keyFile));
                        secretKey = in.readLine();
                        //Check for null or empty secret key
                    } catch (FileNotFoundException e) {
                        throw new RuntimeException("File containing secret key not found: "+s_keyFile, e);
                    } catch (IOException e) {
                        throw new RuntimeException("Error while reading secret key from: "+s_keyFile, e);
                    }
                    
                    if(secretKey == null || secretKey.isEmpty()){
                        throw new RuntimeException("Secret key is null or empty in file "+s_keyFile);
                    }
                    
                } else if(encryptionType.equals("env")){
                    secretKey = System.getenv(s_envKey);
                    if(secretKey == null || secretKey.isEmpty()){
                        throw new RuntimeException("Environment variable "+s_envKey+" is not set or empty");
                    }
                } else if(encryptionType.equals("web")){
                    ServerSocket serverSocket = null;
                    int port = 8097;
                    try {
                        serverSocket = new ServerSocket(port);
                    } catch (IOException ioex) {
                        throw new RuntimeException("Error initializing secret key reciever", ioex);
                    }
                    s_logger.info("Waiting for admin to send secret key on port "+port);
                    Socket clientSocket = null;
                    try {
                        clientSocket = serverSocket.accept();
                    } catch (IOException e) {
                        throw new RuntimeException("Accept failed on "+port);
                    }
                    PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
                    BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
                    String inputLine, outputLine;
                    if ((inputLine = in.readLine()) != null) {
                        secretKey = inputLine;
                    }
                    out.close();
                    in.close();
                    clientSocket.close();
                    serverSocket.close();
                } else {
                    throw new RuntimeException("Invalid encryption type: "+encryptionType);
                }
    
                stringConfig.setPassword(secretKey);
                s_encryptor.setConfig(stringConfig);
                s_useEncryption = true;
            }
        } catch (FileNotFoundException e) {
            throw new RuntimeException("File db.properties not found", e);
        } catch (IOException e) {
            throw new RuntimeException("Error while reading db.properties", e);
        }
    }
    
    public static StandardPBEStringEncryptor getEncryptor() {
        return s_encryptor;
    }
    
    public static boolean useEncryption(){
        return s_useEncryption;
    }
    
    //Initialize encryptor for migration during secret key change
    public static void initEncryptorForMigration(String secretKey){
        s_encryptor.setAlgorithm("PBEWithMD5AndDES");
        SimpleStringPBEConfig stringConfig = new SimpleStringPBEConfig();
        stringConfig.setPassword(secretKey);
        s_encryptor.setConfig(stringConfig);
        s_useEncryption = true;
    }
}