/**
 * 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.pulsar.common.util.keystoretls;

import static org.apache.pulsar.common.util.SecurityUtility.getProvider;

import com.google.common.base.Strings;
import io.netty.handler.ssl.util.InsecureTrustManagerFactory;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.security.GeneralSecurityException;
import java.security.KeyStore;
import java.security.Provider;
import java.security.SecureRandom;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
import javax.net.ssl.KeyManager;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLEngine;
import javax.net.ssl.SSLException;
import javax.net.ssl.TrustManagerFactory;
import lombok.Getter;
import lombok.extern.slf4j.Slf4j;
import org.eclipse.jetty.util.ssl.SslContextFactory;

/**
 * KeyStoreSSLContext that mainly wrap a SSLContext to provide SSL context for both webservice and netty.
 */
@Slf4j
public class KeyStoreSSLContext {
    public static final String DEFAULT_KEYSTORE_TYPE = "JKS";
    public static final String DEFAULT_SSL_PROTOCOL = "TLS";
    public static final String DEFAULT_SSL_ENABLED_PROTOCOLS = "TLSv1.2,TLSv1.1,TLSv1";
    public static final String DEFAULT_SSL_KEYMANGER_ALGORITHM = KeyManagerFactory.getDefaultAlgorithm();
    public static final String DEFAULT_SSL_TRUSTMANAGER_ALGORITHM = TrustManagerFactory.getDefaultAlgorithm();

    public static final Provider BC_PROVIDER = getProvider();

    /**
     * Connection Mode for TLS.
     */
    public enum Mode {
        CLIENT,
        SERVER
    }

    @Getter
    private final Mode mode;

    private String sslProviderString;
    private String keyStoreTypeString;
    private String keyStorePath;
    private String keyStorePassword;
    private boolean allowInsecureConnection;
    private String trustStoreTypeString;
    private String trustStorePath;
    private String trustStorePassword;
    private boolean needClientAuth;
    private Set<String> ciphers;
    private Set<String> protocols;
    @Getter
    private SSLContext sslContext;

    private String protocol = DEFAULT_SSL_PROTOCOL;
    private String kmfAlgorithm = DEFAULT_SSL_KEYMANGER_ALGORITHM;
    private String tmfAlgorithm = DEFAULT_SSL_TRUSTMANAGER_ALGORITHM;

    // only init vars, before using it, need to call createSSLContext to create ssl context.
    public KeyStoreSSLContext(Mode mode,
                              String sslProviderString,
                              String keyStoreTypeString,
                              String keyStorePath,
                              String keyStorePassword,
                              boolean allowInsecureConnection,
                              String trustStoreTypeString,
                              String trustStorePath,
                              String trustStorePassword,
                              boolean requireTrustedClientCertOnConnect,
                              Set<String> ciphers,
                              Set<String> protocols) {
        this.mode = mode;
        this.sslProviderString = sslProviderString;
        this.keyStoreTypeString = Strings.isNullOrEmpty(keyStoreTypeString)
                ? DEFAULT_KEYSTORE_TYPE
                : keyStoreTypeString;
        this.keyStorePath = keyStorePath;
        this.keyStorePassword = keyStorePassword;
        this.trustStoreTypeString = Strings.isNullOrEmpty(trustStoreTypeString)
                ? DEFAULT_KEYSTORE_TYPE
                : trustStoreTypeString;
        this.trustStorePath = trustStorePath;
        this.trustStorePassword = trustStorePassword;
        this.needClientAuth = requireTrustedClientCertOnConnect;
        this.ciphers = ciphers;
        this.protocols = protocols;

        if (protocols != null && protocols.size() > 0) {
            this.protocols = protocols;
        } else {
            this.protocols = new HashSet<>(Arrays.asList(DEFAULT_SSL_ENABLED_PROTOCOLS.split("\\s*,\\s*")));
        }

        if (ciphers != null && ciphers.size() > 0) {
            this.ciphers = ciphers;
        } else {
            this.ciphers = null;
        }

        this.allowInsecureConnection = allowInsecureConnection;
    }

    public SSLContext createSSLContext() throws GeneralSecurityException, IOException {
        SSLContext sslContext;
        if (sslProviderString != null) {
            sslContext = SSLContext.getInstance(protocol, sslProviderString);
        } else {
            sslContext = SSLContext.getInstance(protocol);
        }

        // key store
        KeyManager[] keyManagers = null;
        if (!Strings.isNullOrEmpty(keyStorePath)) {
            KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance(kmfAlgorithm);
            KeyStore keyStore = KeyStore.getInstance(keyStoreTypeString);
            char[] passwordChars = keyStorePassword.toCharArray();
            keyStore.load(new FileInputStream(keyStorePath), passwordChars);
            keyManagerFactory.init(keyStore, passwordChars);
            keyManagers = keyManagerFactory.getKeyManagers();
        }

        // trust store
        TrustManagerFactory trustManagerFactory;
        if (this.allowInsecureConnection) {
            trustManagerFactory = InsecureTrustManagerFactory.INSTANCE;
        } else {
            trustManagerFactory = TrustManagerFactory.getInstance(tmfAlgorithm);
            KeyStore trustStore = KeyStore.getInstance(trustStoreTypeString);
            char[] passwordChars = trustStorePassword.toCharArray();
            trustStore.load(new FileInputStream(trustStorePath), passwordChars);
            trustManagerFactory.init(trustStore);
        }

        // init
        sslContext.init(keyManagers, trustManagerFactory.getTrustManagers(), new SecureRandom());
        this.sslContext = sslContext;
        return sslContext;
    }

    public SSLEngine createSSLEngine() {
        SSLEngine sslEngine = sslContext.createSSLEngine();

        sslEngine.setEnabledProtocols(sslEngine.getSupportedProtocols());
        sslEngine.setEnabledCipherSuites(sslEngine.getSupportedCipherSuites());

        if (this.mode == Mode.SERVER) {
            sslEngine.setNeedClientAuth(this.needClientAuth);
            sslEngine.setUseClientMode(false);
        } else {
            sslEngine.setUseClientMode(true);
        }

        return sslEngine;
    }

    public static KeyStoreSSLContext createClientKeyStoreSslContext(String sslProviderString,
                                                            String keyStoreTypeString,
                                                            String keyStorePath,
                                                            String keyStorePassword,
                                                            boolean allowInsecureConnection,
                                                            String trustStoreTypeString,
                                                            String trustStorePath,
                                                            String trustStorePassword,
                                                            Set<String> ciphers,
                                                            Set<String> protocols)
            throws GeneralSecurityException, SSLException, FileNotFoundException, IOException {
        KeyStoreSSLContext keyStoreSSLContext = new KeyStoreSSLContext(Mode.CLIENT,
                sslProviderString,
                keyStoreTypeString,
                keyStorePath,
                keyStorePassword,
                allowInsecureConnection,
                trustStoreTypeString,
                trustStorePath,
                trustStorePassword,
                false,
                ciphers,
                protocols);

        keyStoreSSLContext.createSSLContext();
        return keyStoreSSLContext;
    }


    public static KeyStoreSSLContext createServerKeyStoreSslContext(String sslProviderString,
                                                    String keyStoreTypeString,
                                                    String keyStorePath,
                                                    String keyStorePassword,
                                                    boolean allowInsecureConnection,
                                                    String trustStoreTypeString,
                                                    String trustStorePath,
                                                    String trustStorePassword,
                                                    boolean requireTrustedClientCertOnConnect,
                                                    Set<String> ciphers,
                                                    Set<String> protocols)
            throws GeneralSecurityException, SSLException, FileNotFoundException, IOException {
        KeyStoreSSLContext keyStoreSSLContext = new KeyStoreSSLContext(Mode.SERVER,
                sslProviderString,
                keyStoreTypeString,
                keyStorePath,
                keyStorePassword,
                allowInsecureConnection,
                trustStoreTypeString,
                trustStorePath,
                trustStorePassword,
                requireTrustedClientCertOnConnect,
                ciphers,
                protocols);

        keyStoreSSLContext.createSSLContext();
        return keyStoreSSLContext;
    }

    // for web server use case, no need ciphers and protocols
    public static SSLContext createServerSslContext(String sslProviderString,
                                                    String keyStoreTypeString,
                                                    String keyStorePath,
                                                    String keyStorePassword,
                                                    boolean allowInsecureConnection,
                                                    String trustStoreTypeString,
                                                    String trustStorePath,
                                                    String trustStorePassword,
                                                    boolean requireTrustedClientCertOnConnect)
            throws GeneralSecurityException, SSLException, FileNotFoundException, IOException {

        return createServerKeyStoreSslContext(
                sslProviderString,
                keyStoreTypeString,
                keyStorePath,
                keyStorePassword,
                allowInsecureConnection,
                trustStoreTypeString,
                trustStorePath,
                trustStorePassword,
                requireTrustedClientCertOnConnect,
                null,
                null).getSslContext();
    }

    // for web client
    public static SSLContext createClientSslContext(String sslProviderString,
                                                    String keyStoreTypeString,
                                                    String keyStorePath,
                                                    String keyStorePassword,
                                                    boolean allowInsecureConnection,
                                                    String trustStoreTypeString,
                                                    String trustStorePath,
                                                    String trustStorePassword,
                                                    Set<String> ciphers,
                                                    Set<String> protocol)
            throws GeneralSecurityException, SSLException, FileNotFoundException, IOException {
        KeyStoreSSLContext keyStoreSSLContext = new KeyStoreSSLContext(Mode.CLIENT,
                sslProviderString,
                keyStoreTypeString,
                keyStorePath,
                keyStorePassword,
                allowInsecureConnection,
                trustStoreTypeString,
                trustStorePath,
                trustStorePassword,
                false,
                ciphers,
                protocol);

        return keyStoreSSLContext.createSSLContext();
    }

    // for web client
    public static SSLContext createClientSslContext(String keyStoreTypeString,
                                                    String keyStorePath,
                                                    String keyStorePassword,
                                                    String trustStoreTypeString,
                                                    String trustStorePath,
                                                    String trustStorePassword)
            throws GeneralSecurityException, SSLException, FileNotFoundException, IOException {
        KeyStoreSSLContext keyStoreSSLContext = new KeyStoreSSLContext(Mode.CLIENT,
                null,
                keyStoreTypeString,
                keyStorePath,
                keyStorePassword,
                false,
                trustStoreTypeString,
                trustStorePath,
                trustStorePassword,
                false,
                null,
                null);

        return keyStoreSSLContext.createSSLContext();
    }

    // for web server. autoRefresh is default true.
    public static SslContextFactory createSslContextFactory(String sslProviderString,
                                                            String keyStoreTypeString,
                                                            String keyStore,
                                                            String keyStorePassword,
                                                            boolean allowInsecureConnection,
                                                            String trustStoreTypeString,
                                                            String trustStore,
                                                            String trustStorePassword,
                                                            boolean requireTrustedClientCertOnConnect,
                                                            long certRefreshInSec)
            throws GeneralSecurityException, SSLException, FileNotFoundException, IOException {
        SslContextFactory sslCtxFactory;

        sslCtxFactory = new SslContextFactoryWithAutoRefresh(
                sslProviderString,
                keyStoreTypeString,
                keyStore,
                keyStorePassword,
                allowInsecureConnection,
                trustStoreTypeString,
                trustStore,
                trustStorePassword,
                requireTrustedClientCertOnConnect,
                certRefreshInSec);

        if (requireTrustedClientCertOnConnect) {
            sslCtxFactory.setNeedClientAuth(true);
        } else {
            sslCtxFactory.setWantClientAuth(true);
        }
        sslCtxFactory.setTrustAll(true);

        return sslCtxFactory;
    }
}
