/*

 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

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 */

package jdk.internal.event;

import jdk.internal.access.JavaUtilJarAccess;

import jdk.internal.access.SharedSecrets;

import java.lang.invoke.MethodHandles;

import java.lang.invoke.VarHandle;

import java.time.Duration;

import java.time.Instant;

import java.util.Date;

import java.util.stream.Collectors;

import java.util.stream.IntStream;

/**

 * A helper class to have events logged to a JDK Event Logger.

 */

public final class EventHelper {

    private static final JavaUtilJarAccess JUJA = SharedSecrets.javaUtilJarAccess();

    private static volatile boolean loggingSecurity;

    private static volatile System.Logger securityLogger;

    private static final VarHandle LOGGER_HANDLE;

    static {

        try {

            LOGGER_HANDLE =

                    MethodHandles.lookup().findStaticVarHandle(

                            EventHelper.class, "securityLogger", System.Logger.class);

        } catch (ReflectiveOperationException e) {

            throw new Error(e);

        }

    }

    private static final System.Logger.Level LOG_LEVEL = System.Logger.Level.DEBUG;

    // helper class used for logging security related events for now

    private static final String SECURITY_LOGGER_NAME = "jdk.event.security";

    public static void logTLSHandshakeEvent(Instant start,

                                            String peerHost,

                                            int peerPort,

                                            String cipherSuite,

                                            String protocolVersion,

                                            long peerCertId) {

        assert securityLogger != null;

        String prepend = getDurationString(start);

        securityLogger.log(LOG_LEVEL, prepend +

        " TLSHandshake: {0}:{1,number,#}, {2}, {3}, {4,number,#}",

        peerHost, peerPort, protocolVersion, cipherSuite, peerCertId);

    }

    public static void logSecurityPropertyEvent(String key,

                                                String value) {

        assert securityLogger != null;

        securityLogger.log(LOG_LEVEL,

            "SecurityPropertyModification: key:{0}, value:{1}", key, value);

    }

    public static void logX509ValidationEvent(int anchorCertId,

                                         int[] certIds) {

        assert securityLogger != null;

        String codes = IntStream.of(certIds)

                .mapToObj(Integer::toString)

                .collect(Collectors.joining(", "));

        securityLogger.log(LOG_LEVEL,

                "ValidationChain: {0,number,#}, {1}", anchorCertId, codes);

    }

    public static void logX509CertificateEvent(String algId,

                                               String serialNum,

                                               String subject,

                                               String issuer,

                                               String keyType,

                                               int length,

                                               long certId,

                                               long beginDate,

                                               long endDate) {

        assert securityLogger != null;

        securityLogger.log(LOG_LEVEL, "X509Certificate: Alg:{0}, Serial:{1}" +

            ", Subject:{2}, Issuer:{3}, Key type:{4}, Length:{5,number,#}" +

            ", Cert Id:{6,number,#}, Valid from:{7}, Valid until:{8}",

            algId, serialNum, subject, issuer, keyType, length,

            certId, new Date(beginDate), new Date(endDate));

    }

    /**

     * Method to calculate a duration timestamp for events which measure

     * the start and end times of certain operations.

     * @param start Instant indicating when event started recording

     * @return A string representing duraction from start time to

     * time of this method call. Empty string is start is null.

     */

    private static String getDurationString(Instant start) {

        if (start != null) {

            if (start.equals(Instant.MIN)) {

                return "N/A";

            }

            Duration duration = Duration.between(start, Instant.now());

            long micros = duration.toNanos() / 1_000;

            if (micros < 1_000_000) {

                return "duration = " + (micros / 1_000.0) + " ms:";

            } else {

                return "duration = " + ((micros / 1_000) / 1_000.0) + " s:";

            }

        } else {

            return "";

        }

    }

    /**

     * Helper to determine if security events are being logged

     * at a preconfigured logging level. The configuration value

     * is read once at class initialization.

     *

     * @return boolean indicating whether an event should be logged

     */

    public static boolean isLoggingSecurity() {

        // Avoid a bootstrap issue where the commitEvent attempts to

        // trigger early loading of System Logger but where

        // the verification process still has JarFiles locked

        if (securityLogger == null && !JUJA.isInitializing()) {

            LOGGER_HANDLE.compareAndSet( null, System.getLogger(SECURITY_LOGGER_NAME));

            loggingSecurity = securityLogger.isLoggable(LOG_LEVEL);

        }

        return loggingSecurity;

    }

}