/*******************************************************************************
 * ============LICENSE_START====================================================
 * * org.onap.aaf
 * * ===========================================================================
 * * Copyright © 2017 AT&T Intellectual Property. All rights reserved.
 * * ===========================================================================
 * * Licensed 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.
 * * ============LICENSE_END====================================================
 * *
 * * ECOMP is a trademark and service mark of AT&T Intellectual Property.
 * *
 ******************************************************************************/
package com.att.cadi.config;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.rmi.AccessException;
import java.security.GeneralSecurityException;
import java.security.KeyStore;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.util.ArrayList;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.KeyManager;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509KeyManager;
import javax.net.ssl.X509TrustManager;

import com.att.cadi.Access;
import com.att.cadi.Access.Level;
import com.att.cadi.util.MaskFormatException;
import com.att.cadi.util.NetMask;

public class SecurityInfo {
	private static final String SECURITY_ALGO = "RSA";
	private static final String HTTPS_PROTOCOLS = "https.protocols";
	private static final String JDK_TLS_CLIENT_PROTOCOLS = "jdk.tls.client.protocols";

	public static final String HTTPS_PROTOCOLS_DEFAULT = "TLSv1.1,TLSv1.2";
	public static final String REGEX_COMMA = "\\s*,\\s*";
	public static final String SslKeyManagerFactoryAlgorithm;
	
	private SSLSocketFactory scf;
	private X509KeyManager[] km;
	private X509TrustManager[] tm;
	public final String default_alias;
	private NetMask[] trustMasks;
	private SSLContext ctx;
	private HostnameVerifier maskHV;

	// Change Key Algorithms for IBM's VM.  Could put in others, if needed.
	static {
		if(System.getProperty("java.vm.vendor").equalsIgnoreCase("IBM Corporation")) {
			SslKeyManagerFactoryAlgorithm = "IbmX509";
		} else {
			SslKeyManagerFactoryAlgorithm = "SunX509";
		}
	}
	

	public SecurityInfo(final Access access) throws GeneralSecurityException, IOException {
		// reuse DME2 Properties for convenience if specific Properties don't exist
		String keyStore = access.getProperty(Config.CADI_KEYSTORE,
				access.getProperty(Config.AFT_DME2_KEYSTORE,null));
		String keyStorePasswd = access.getProperty(Config.CADI_KEYSTORE_PASSWORD,
				access.getProperty(Config.AFT_DME2_KEYSTORE_PASSWORD, null));
		keyStorePasswd = keyStorePasswd==null?null:access.decrypt(keyStorePasswd,false);
		String trustStore = access.getProperty(Config.CADI_TRUSTSTORE,
				access.getProperty(Config.AFT_DME2_TRUSTSTORE, null));
		String trustStorePasswd = access.getProperty(Config.CADI_TRUSTSTORE_PASSWORD,
				access.getProperty(Config.AFT_DME2_TRUSTSTORE_PASSWORD,null));
		trustStorePasswd = trustStorePasswd==null?null:access.decrypt(trustStorePasswd,false);
		default_alias = access.getProperty(Config.CADI_ALIAS, 
				access.getProperty(Config.AFT_DME2_CLIENT_SSL_CERT_ALIAS,null));
		
		String keyPasswd = access.getProperty(Config.CADI_KEY_PASSWORD,null);
		keyPasswd = keyPasswd==null?keyStorePasswd:access.decrypt(keyPasswd,false);
		String tips=access.getProperty(Config.CADI_TRUST_MASKS, null);
		if(tips!=null) {
			access.log(Level.INIT,"Explicitly accepting valid X509s from",tips);
			String[] ipsplit = tips.split(REGEX_COMMA);
			trustMasks = new NetMask[ipsplit.length];
			for(int i=0;i<ipsplit.length;++i) {
				try {
					trustMasks[i]=new NetMask(ipsplit[i]);
				} catch (MaskFormatException e) {
					throw new AccessException("Invalid IP Mask in " + Config.CADI_TRUST_MASKS,e);
				}
			}
		}
		String https_protocols = Config.logProp(access,Config.CADI_PROTOCOLS, 
				access.getProperty(Config.AFT_DME2_SSL_INCLUDE_PROTOCOLS, 
					access.getProperty(HTTPS_PROTOCOLS,HTTPS_PROTOCOLS_DEFAULT)
					));
		System.setProperty(HTTPS_PROTOCOLS,https_protocols);
		System.setProperty(JDK_TLS_CLIENT_PROTOCOLS, https_protocols);
		
		KeyManagerFactory kmf = KeyManagerFactory.getInstance(SslKeyManagerFactoryAlgorithm);
		File file;


		if(keyStore==null || keyStorePasswd == null) { 
			km = new X509KeyManager[0];
		} else {
			ArrayList<X509KeyManager> kmal = new ArrayList<X509KeyManager>();
			for(String ksname : keyStore.split(REGEX_COMMA)) {
				file = new File(ksname);
				String keystoreFormat;
				if(ksname.endsWith("pkcs12")) {
					keystoreFormat = "PKCS12";
				} else {
					keystoreFormat = "JKS";
				}
				if(file.exists()) {
					FileInputStream fis = new FileInputStream(file);
					try {
						KeyStore ks = KeyStore.getInstance(keystoreFormat);
						ks.load(fis, keyStorePasswd.toCharArray());
						kmf.init(ks, keyPasswd.toCharArray());
					} finally {
						fis.close();
					}
				}
			}
			for(KeyManager km : kmf.getKeyManagers()) {
				if(km instanceof X509KeyManager) {
					kmal.add((X509KeyManager)km);
				}
			}
			km = new X509KeyManager[kmal.size()];
			kmal.toArray(km);
		}

		TrustManagerFactory tmf = TrustManagerFactory.getInstance(SslKeyManagerFactoryAlgorithm);
		if(trustStore!=null) {
			for(String tsname : trustStore.split(REGEX_COMMA)) {
				file = new File(tsname);
				if(file.exists()) {
					FileInputStream fis = new FileInputStream(file);
					try {
						KeyStore ts = KeyStore.getInstance("JKS");
						ts.load(fis, trustStorePasswd.toCharArray());
						tmf.init(ts); 
					} finally {
						fis.close();
					}
				}
			}
			TrustManager tms[] = tmf.getTrustManagers();
			tm = new X509TrustManager[tms==null?0:tms.length];
			for(int i=0;i<tms.length;++i) {
				try {
					tm[i]=(X509TrustManager)tms[i];
				} catch (ClassCastException e) {
					access.log(Level.WARN, "Non X509 TrustManager", tm[i].getClass().getName(),"skipped in SecurityInfo");
				}
			}
		}
		
		if(trustMasks!=null) {
			final HostnameVerifier origHV = HttpsURLConnection.getDefaultHostnameVerifier();
			HttpsURLConnection.setDefaultHostnameVerifier(maskHV = new HostnameVerifier() {
				@Override
				public boolean verify(final String urlHostName, final SSLSession session) {
					try {
						// This will pick up /etc/host entries as well as DNS
						InetAddress ia = InetAddress.getByName(session.getPeerHost());
						for(NetMask tmask : trustMasks) {
							if(tmask.isInNet(ia.getHostAddress())) {
								return true;
							}
						}
					} catch (UnknownHostException e) {
						// It's ok. do normal Verify
					}
					return origHV.verify(urlHostName,session);
				};
			});
		}
		ctx = SSLContext.getInstance("TLS");
		ctx.init(km, tm, null);
		SSLContext.setDefault(ctx);
		scf = ctx.getSocketFactory();
	}

	/**
	 * @return the scf
	 */
	public SSLSocketFactory getSSLSocketFactory() {
		return scf;
	}

	public SSLContext getSSLContext() {
		return ctx;
	}

	/**
	 * @return the km
	 */
	public X509KeyManager[] getKeyManagers() {
		return km;
	}

	public void checkClientTrusted(X509Certificate[] certarr) throws CertificateException {
		for(X509TrustManager xtm : tm) {
			xtm.checkClientTrusted(certarr, SECURITY_ALGO);
		}
	}

	public void checkServerTrusted(X509Certificate[] certarr) throws CertificateException {
		for(X509TrustManager xtm : tm) {
			xtm.checkServerTrusted(certarr, SECURITY_ALGO);
		}
	}

	public void setSocketFactoryOn(HttpsURLConnection hsuc) {
		hsuc.setSSLSocketFactory(scf);
		if(maskHV!=null && !maskHV.equals(hsuc.getHostnameVerifier())) {
			hsuc.setHostnameVerifier(maskHV);
		}
	}

}