/**
 * 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 org.apache.cxf.transport.https;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.lang.reflect.Method;
import java.security.KeyManagementException;
import java.security.KeyStore;
import java.security.NoSuchAlgorithmException;
import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.net.ssl.KeyManager;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.servlet.http.HttpServletRequest;

import org.apache.cxf.common.logging.LogUtils;
import org.apache.cxf.configuration.security.FiltersType;
import org.apache.cxf.message.Message;
import org.apache.cxf.security.transport.TLSSessionInfo;


/**
 * Holder for utility methods related to manipulating SSL settings, common
 * to the connection and listener factories (previously duplicated).
 */
public final class SSLUtils {

    static final String PKCS12_TYPE = "PKCS12";

    private static final String DEFAULT_KEYSTORE_TYPE = "PKCS12";
    private static final String DEFAULT_TRUST_STORE_TYPE = "JKS";
    private static final String DEFAULT_SECURE_SOCKET_PROTOCOL = "TLSv1";
    private static final String CERTIFICATE_FACTORY_TYPE = "X.509";
    private static final String SSL_CIPHER_SUITE_ATTRIBUTE = "javax.servlet.request.cipher_suite";
    private static final String SSL_PEER_CERT_CHAIN_ATTRIBUTE = "javax.servlet.request.X509Certificate";
    
    private static final boolean DEFAULT_REQUIRE_CLIENT_AUTHENTICATION = false;
    private static final boolean DEFAULT_WANT_CLIENT_AUTHENTICATION = true;
    
    /**
     * By default, only include export-compatible ciphersuites.
     */
    private static final List<String> DEFAULT_CIPHERSUITE_FILTERS_INCLUDE =
        Arrays.asList(new String[] {".*_EXPORT_.*",
                                    ".*_EXPORT1024_.*",
                                    ".*_WITH_DES_.*",
                                    ".*_WITH_NULL_.*"});


    private SSLUtils() {
    }    
    
    public static KeyManager[] getKeyStoreManagers(
                                          String keyStoreLocation,
                                          String keyStoreType,
                                          String keyStorePassword,
                                          String keyPassword,
                                          String keyStoreMgrFactoryAlgorithm,
                                          String secureSocketProtocol,
                                          Logger log)
        throws Exception {
        //TODO for performance reasons we should cache
        // the KeymanagerFactory and TrustManagerFactory 
        if ((keyStorePassword != null)
            && (keyPassword != null) 
            && (!keyStorePassword.equals(keyPassword))) {
            LogUtils.log(log,
                         Level.WARNING,
                         "KEY_PASSWORD_NOT_SAME_KEYSTORE_PASSWORD");
        }
        KeyManager[] keystoreManagers = null;        
        KeyManagerFactory kmf = 
            KeyManagerFactory.getInstance(keyStoreMgrFactoryAlgorithm);  
        KeyStore ks = KeyStore.getInstance(keyStoreType);
        
        if (keyStoreType.equalsIgnoreCase(PKCS12_TYPE)) {
            FileInputStream fis = new FileInputStream(keyStoreLocation);
            DataInputStream dis = new DataInputStream(fis);
            byte[] bytes = new byte[dis.available()];
            dis.readFully(bytes);
            ByteArrayInputStream bin = new ByteArrayInputStream(bytes);
            
            if (keyStorePassword != null) {
                keystoreManagers = loadKeyStore(kmf,
                                                ks,
                                                bin,
                                                keyStoreLocation,
                                                keyStorePassword,
                                                log);
            }
        } else {        
            byte[] sslCert = loadClientCredential(keyStoreLocation);
            
            if (sslCert != null && sslCert.length > 0 && keyStorePassword != null) {
                ByteArrayInputStream bin = new ByteArrayInputStream(sslCert);
                keystoreManagers = loadKeyStore(kmf,
                                                ks,
                                                bin,
                                                keyStoreLocation,
                                                keyStorePassword,
                                                log);
            }  
        }
        if ((keyStorePassword == null) && (keyStoreLocation != null)) {
            LogUtils.log(log, Level.WARNING,
                         "FAILED_TO_LOAD_KEYSTORE_NULL_PASSWORD", 
                         keyStoreLocation);
        }
        return keystoreManagers;
    }

    public static KeyManager[] loadKeyStore(KeyManagerFactory kmf,
                                               KeyStore ks,
                                               ByteArrayInputStream bin,
                                               String keyStoreLocation,
                                               String keyStorePassword,
                                               Logger log) {
        KeyManager[] keystoreManagers = null;
        try {
            ks.load(bin, keyStorePassword.toCharArray());
            kmf.init(ks, keyStorePassword.toCharArray());
            keystoreManagers = kmf.getKeyManagers();
            LogUtils.log(log,
                         Level.INFO,
                         "LOADED_KEYSTORE",
                         keyStoreLocation);
        } catch (Exception e) {
            LogUtils.log(log,
                         Level.WARNING,
                         "FAILED_TO_LOAD_KEYSTORE", 
                         new Object[]{keyStoreLocation, e.getMessage()});
        } 
        return keystoreManagers;
    }

    public static TrustManager[] getTrustStoreManagers(
                                        boolean pkcs12,
                                        String trustStoreType,
                                        String trustStoreLocation,
                                        String trustStoreMgrFactoryAlgorithm,
                                        Logger log)
        throws Exception {
        // ********************** Load Trusted CA file **********************
        
        TrustManager[] trustStoreManagers = null;
        KeyStore trustedCertStore = KeyStore.getInstance(trustStoreType);

        if (pkcs12) {
            //TODO could support multiple trust cas
            trustStoreManagers = new TrustManager[1];
            
            trustedCertStore.load(null, "".toCharArray());
            CertificateFactory cf = CertificateFactory.getInstance(CERTIFICATE_FACTORY_TYPE);
            byte[] caCert = loadCACert(trustStoreLocation);
            try {
                if (caCert != null) {
                    ByteArrayInputStream cabin = new ByteArrayInputStream(caCert);
                    X509Certificate cert = (X509Certificate)cf.generateCertificate(cabin);
                    trustedCertStore.setCertificateEntry(cert.getIssuerDN().toString(), cert);
                    cabin.close();
                }
            } catch (Exception e) {
                LogUtils.log(log, Level.WARNING, "FAILED_TO_LOAD_TRUST_STORE", 
                             new Object[]{trustStoreLocation, e.getMessage()});
            } 
        } else {
            trustedCertStore.load(new FileInputStream(trustStoreLocation), null);
        }
        
        TrustManagerFactory tmf  = 
            TrustManagerFactory.getInstance(trustStoreMgrFactoryAlgorithm);
        tmf.init(trustedCertStore);
        LogUtils.log(log, Level.INFO, "LOADED_TRUST_STORE", trustStoreLocation);
        trustStoreManagers = tmf.getTrustManagers();

        return trustStoreManagers;
    }
    
    protected static byte[] loadClientCredential(String fileName) throws IOException {
        if (fileName == null) {
            return null;
        }
        FileInputStream in = new FileInputStream(fileName);
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        byte[] buf = new byte[512];
        int i = in.read(buf);
        while (i  > 0) {
            out.write(buf, 0, i);
            i = in.read(buf);
        }
        in.close();
        return out.toByteArray();
    }

    protected static byte[] loadCACert(String fileName) throws IOException {
        if (fileName == null) {
            return null;
        }
        FileInputStream in = new FileInputStream(fileName);
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        byte[] buf = new byte[512];
        int i = in.read(buf);
        
        while (i > 0) {
            out.write(buf, 0, i);
            i = in.read(buf);
        }
        in.close();
        return out.toByteArray();
    }

    public static String getKeystore(String keyStoreLocation, Logger log) {
        String logMsg = null;
        if (keyStoreLocation != null) {
            logMsg = "KEY_STORE_SET";
        } else {
            keyStoreLocation = System.getProperty("javax.net.ssl.keyStore");
            if (keyStoreLocation != null) {
                logMsg = "KEY_STORE_SYSTEM_PROPERTY_SET";
            } else {
                keyStoreLocation =
                    System.getProperty("user.home") + "/.keystore";
                logMsg = "KEY_STORE_NOT_SET";
            }
        }
        LogUtils.log(log, Level.INFO, logMsg, keyStoreLocation);
        return keyStoreLocation;
    }
    
    public static String getKeystoreType(String keyStoreType, Logger log) {
        String logMsg = null;
        if (keyStoreType != null) {
            logMsg = "KEY_STORE_TYPE_SET";
        } else {
            keyStoreType = DEFAULT_KEYSTORE_TYPE;
            logMsg = "KEY_STORE_TYPE_NOT_SET";
        }
        LogUtils.log(log, Level.INFO, logMsg, keyStoreType);
        return keyStoreType;
    }  
    
    public static String getKeystorePassword(String keyStorePassword,
                                             Logger log) {
        String logMsg = null;
        if (keyStorePassword != null) {
            logMsg = "KEY_STORE_PASSWORD_SET";
        } else {
            keyStorePassword =
                System.getProperty("javax.net.ssl.keyStorePassword");
            logMsg = keyStorePassword != null
                     ? "KEY_STORE_PASSWORD_SYSTEM_PROPERTY_SET"
                     : "KEY_STORE_PASSWORD_NOT_SET";
        }
        LogUtils.log(log, Level.INFO, logMsg);
        return keyStorePassword;        
    }
    
    public static String getKeyPassword(String keyPassword, Logger log) {
        String logMsg = null;
        if (keyPassword != null) {
            logMsg = "KEY_PASSWORD_SET";
        } else {
            keyPassword =
                System.getProperty("javax.net.ssl.keyStorePassword");
            logMsg = keyPassword != null
                     ? "KEY_PASSWORD_SYSTEM_PROPERTY_SET"
                     : "KEY_PASSWORD_NOT_SET";
        }
        LogUtils.log(log, Level.INFO, logMsg);
        return keyPassword;
    }

    public static String getKeystoreAlgorithm(
                                          String keyStoreMgrFactoryAlgorithm,
                                          Logger log) {
        String logMsg = null;
        if (keyStoreMgrFactoryAlgorithm != null) {
            logMsg = "KEY_STORE_ALGORITHM_SET";
        } else {
            keyStoreMgrFactoryAlgorithm =
                KeyManagerFactory.getDefaultAlgorithm();
            logMsg = "KEY_STORE_ALGORITHM_NOT_SET";
        }
        LogUtils.log(log, Level.INFO, logMsg, keyStoreMgrFactoryAlgorithm);
        return keyStoreMgrFactoryAlgorithm;
    } 
    
    public static String getTrustStoreAlgorithm(
                                        String trustStoreMgrFactoryAlgorithm,
                                        Logger log) {
        String logMsg = null;
        if (trustStoreMgrFactoryAlgorithm != null) {
            logMsg = "TRUST_STORE_ALGORITHM_SET";
        } else {
            trustStoreMgrFactoryAlgorithm =
                TrustManagerFactory.getDefaultAlgorithm();
            logMsg = "TRUST_STORE_ALGORITHM_NOT_SET";
        }
        LogUtils.log(log, Level.INFO, logMsg, trustStoreMgrFactoryAlgorithm);
        return trustStoreMgrFactoryAlgorithm;
    }    
    
    public static SSLContext getSSLContext(String protocol,
                                           KeyManager[] keyStoreManagers,
                                           TrustManager[] trustStoreManagers)
        throws NoSuchAlgorithmException, KeyManagementException {
        SSLContext ctx = SSLContext.getInstance(protocol);
        ctx.init(keyStoreManagers, trustStoreManagers, null);
        return ctx;
    }
    
    public static String[] getSupportedCipherSuites(SSLContext context) {
        return context.getSocketFactory().getSupportedCipherSuites();
    }

    public static String[] getServerSupportedCipherSuites(SSLContext context) {
        return context.getServerSocketFactory().getSupportedCipherSuites();
    }
        
    public static String[] getCiphersuites(List<String> cipherSuitesList,
                                           String[] supportedCipherSuites,
                                           FiltersType filters,
                                           Logger log, boolean exclude) {
        String[] cipherSuites = null;
        if (!(cipherSuitesList == null || cipherSuitesList.isEmpty())) {
            cipherSuites = getCiphersFromList(cipherSuitesList, log);
        } else {
            LogUtils.log(log, Level.INFO, "CIPHERSUITES_NOT_SET");
            if (filters == null) {
                LogUtils.log(log, Level.INFO, "CIPHERSUITE_FILTERS_NOT_SET");                
            }
            List<String> filteredCipherSuites = new ArrayList<String>();
            List<String> excludedCipherSuites = new ArrayList<String>();
            List<Pattern> includes =
                filters != null
                ? compileRegexPatterns(filters.getInclude(), true, log)
                : compileRegexPatterns(DEFAULT_CIPHERSUITE_FILTERS_INCLUDE, true, log);
            List<Pattern> excludes =
                filters != null
                ? compileRegexPatterns(filters.getExclude(), false, log)
                : null;
            for (int i = 0; i < supportedCipherSuites.length; i++) {
                if (matchesOneOf(supportedCipherSuites[i], includes)
                    && !matchesOneOf(supportedCipherSuites[i], excludes)) {
                    LogUtils.log(log,
                                 Level.INFO,
                                 "CIPHERSUITE_INCLUDED",
                                 supportedCipherSuites[i]);
                    filteredCipherSuites.add(supportedCipherSuites[i]);
                } else {
                    LogUtils.log(log,
                                 Level.INFO,
                                 "CIPHERSUITE_EXCLUDED",
                                 supportedCipherSuites[i]);
                    excludedCipherSuites.add(supportedCipherSuites[i]);
                }
            }
            LogUtils.log(log,
                         Level.INFO,
                         "CIPHERSUITES_FILTERED",
                         filteredCipherSuites);
            LogUtils.log(log,
                         Level.INFO,
                         "CIPHERSUITES_EXCLUDED",
                         excludedCipherSuites);
            if (exclude) {
                cipherSuites = getCiphersFromList(excludedCipherSuites, log);
            } else {
                cipherSuites = getCiphersFromList(filteredCipherSuites, log);
            }
        } 
        return cipherSuites;
    }         
    
    private static List<Pattern> compileRegexPatterns(List<String> regexes,
                                                      boolean include,
                                                      Logger log) {
        List<Pattern> patterns = new ArrayList<Pattern>();
        if (regexes != null) {
            String msg = include
                         ? "CIPHERSUITE_INCLUDE_FILTER"
                         : "CIPHERSUITE_EXCLUDE_FILTER";
            for (String s : regexes) {
                LogUtils.log(log, Level.INFO, msg, s);
                patterns.add(Pattern.compile(s));
            }
        }
        return patterns;
    }
    
    private static boolean matchesOneOf(String s, List<Pattern> patterns) {
        boolean matches = false;
        if (patterns != null) {
            for (Pattern pattern : patterns) {
                Matcher matcher = pattern.matcher(s);
                if (matcher.matches()) {
                    matches = true;
                    break;
                }
            }
        }
        return matches;
    }
    
    private static String[] getCiphersFromList(List<String> cipherSuitesList,
                                               Logger log) {
        int numCipherSuites = cipherSuitesList.size();
        String[] cipherSuites = new String[numCipherSuites];
        String ciphsStr = null;
        for (int i = 0; i < numCipherSuites; i++) {
            cipherSuites[i] = cipherSuitesList.get(i);
            if (ciphsStr == null) {
                ciphsStr = cipherSuites[i];
            } else {
                ciphsStr += ", " + cipherSuites[i];
            }
        }
        LogUtils.log(log, Level.INFO, "CIPHERSUITES_SET", ciphsStr);
        return cipherSuites;
    }
    
    public static String getTrustStore(String trustStoreLocation, Logger log) {
        String logMsg = null;
        if (trustStoreLocation != null) {
            logMsg = "TRUST_STORE_SET";
        } else {            
            trustStoreLocation = System.getProperty("javax.net.ssl.trustStore");
            if (trustStoreLocation != null) {
                logMsg = "TRUST_STORE_SYSTEM_PROPERTY_SET";
            } else {
                trustStoreLocation =
                    System.getProperty("java.home") + "/lib/security/cacerts";
                logMsg = "TRUST_STORE_NOT_SET";
            }
        }
        LogUtils.log(log, Level.INFO, logMsg, trustStoreLocation);
        return trustStoreLocation;
    }
    
    public static String getTrustStoreType(String trustStoreType, Logger log) {
        String logMsg = null;
        if (trustStoreType != null) {
            logMsg = "TRUST_STORE_TYPE_SET";
        } else {
            //Can default to JKS
            trustStoreType = DEFAULT_TRUST_STORE_TYPE;
            logMsg = "TRUST_STORE_TYPE_NOT_SET";
        }
        LogUtils.log(log, Level.INFO, logMsg, trustStoreType);
        return trustStoreType;
    }
    
    public static String getSecureSocketProtocol(String secureSocketProtocol,
                                                 Logger log) {
        if (secureSocketProtocol != null) {
            LogUtils.log(log,
                         Level.INFO,
                         "SECURE_SOCKET_PROTOCOL_SET",
                         secureSocketProtocol);
        } else {
            LogUtils.log(log, Level.INFO, "SECURE_SOCKET_PROTOCOL_NOT_SET");
            secureSocketProtocol = DEFAULT_SECURE_SOCKET_PROTOCOL;
        }
        return secureSocketProtocol;
    }
    
    public static boolean getRequireClientAuthentication(
                                    boolean isSetRequireClientAuthentication,
                                    Boolean isRequireClientAuthentication,
                                    Logger log) {
        boolean requireClientAuthentication =
            DEFAULT_REQUIRE_CLIENT_AUTHENTICATION;
        if (isSetRequireClientAuthentication) {
            requireClientAuthentication =
                isRequireClientAuthentication.booleanValue();
            LogUtils.log(log,
                         Level.INFO,
                         "REQUIRE_CLIENT_AUTHENTICATION_SET", 
                         requireClientAuthentication);
        } else {
            LogUtils.log(log,
                         Level.WARNING,
                         "REQUIRE_CLIENT_AUTHENTICATION_NOT_SET");
        }
        return requireClientAuthentication;
    }
    
    public static boolean getWantClientAuthentication(
                                       boolean isSetWantClientAuthentication,
                                       Boolean isWantClientAuthentication,
                                       Logger log) {
        boolean wantClientAuthentication =
            DEFAULT_WANT_CLIENT_AUTHENTICATION;
        if (isSetWantClientAuthentication) {
            wantClientAuthentication =
                isWantClientAuthentication.booleanValue();
            LogUtils.log(log,
                         Level.INFO,
                         "WANT_CLIENT_AUTHENTICATION_SET", 
                         wantClientAuthentication);
        } else {
            LogUtils.log(log,
                         Level.WARNING,
                         "WANT_CLIENT_AUTHENTICATION_NOT_SET");
        } 
        return wantClientAuthentication;
    }    
   
    /**
     * Propogate in the message a TLSSessionInfo instance representative  
     * of the TLS-specific information in the HTTP request.
     * 
     * @param req the Jetty request
     * @param message the Message
     */
    public static void propogateSecureSession(HttpServletRequest request,
                                              Message message) {    
        final String cipherSuite = 
            (String) request.getAttribute(SSL_CIPHER_SUITE_ATTRIBUTE);
        if (cipherSuite != null) {
            final Certificate[] certs = 
                (Certificate[]) request.getAttribute(SSL_PEER_CERT_CHAIN_ATTRIBUTE);
            message.put(TLSSessionInfo.class,
                        new TLSSessionInfo(cipherSuite,
                                           null,
                                           certs));
        }
    }
    
    public static void logUnSupportedPolicies(Object policy,
                                                 boolean client,
                                                 String[] unsupported,
                                                 Logger log) {
        for (int i = 0; i < unsupported.length; i++) {
            try {
                Method method = policy.getClass().getMethod("isSet" + unsupported[i]);
                boolean isSet =
                    ((Boolean)method.invoke(policy, (Object[])null)).booleanValue();
                logUnSupportedPolicy(isSet, client, unsupported[i], log);
            } catch (Exception e) {
                // ignore
            }
        }
    }
    
    private static void logUnSupportedPolicy(boolean isSet,
                                             boolean client,
                                             String policy,
                                             Logger log) {
        if (isSet) {
            LogUtils.log(log,
                         Level.WARNING,
                         client
                         ? "UNSUPPORTED_SSL_CLIENT_POLICY_DATA"
                         : "UNSUPPORTED_SSL_SERVER_POLICY_DATA",
                         policy);
        }    
    }
    
    public static boolean testAllDataHasSetupMethod(Object policy,
                                                       String[] unsupported,
                                                       String[] derivative) {
        Method[] sslPolicyMethods = policy.getClass().getDeclaredMethods();
        Method[] methods = SSLUtils.class.getMethods();
        boolean ok = true;
        
        for (int i = 0; i < sslPolicyMethods.length && ok; i++) {
            String sslPolicyMethodName = sslPolicyMethods[i].getName();
            if (sslPolicyMethodName.startsWith("isSet")) {
                String dataName = 
                    sslPolicyMethodName.substring("isSet".length(),
                                                  sslPolicyMethodName.length());
                String thisMethodName = "get" + dataName;
                ok = hasMethod(methods, thisMethodName)
                     || isExcluded(unsupported, dataName)
                     || isExcluded(derivative, dataName);
            }
        }
        return ok;
    }
    
    private static boolean hasMethod(Method[] methods, String methodName) {
        boolean found = false;
        for (int i = 0; i < methods.length && !found; i++) {
            found = methods[i].getName().equals(methodName);
        }
        return found;
    }
    
    private static boolean isExcluded(String[] excluded,
                                      String dataName) {
        boolean found = false;
        for (int i = 0; i < excluded.length && !found; i++) {
            found = excluded[i].equals(dataName);
        }
        return found;
        
    }
}
