/*
 * 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.logging.log4j.core.impl;

import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.Marker;
import org.apache.logging.log4j.ThreadContext;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.config.Property;
import org.apache.logging.log4j.core.util.Clock;
import org.apache.logging.log4j.core.util.ClockFactory;
import org.apache.logging.log4j.message.LoggerNameAwareMessage;
import org.apache.logging.log4j.message.Message;
import org.apache.logging.log4j.message.TimestampMessage;
import org.apache.logging.log4j.util.Strings;

/**
 * Implementation of a LogEvent.
 */
public class Log4jLogEvent implements LogEvent {

    private static final long serialVersionUID = -1351367343806656055L;
    private static final Clock clock = ClockFactory.getClock();
    private final String loggerFqcn;
    private final Marker marker;
    private final Level level;
    private final String loggerName;
    private final Message message;
    private final long timeMillis;
    private transient final Throwable thrown;
    private ThrowableProxy thrownProxy;
    private final Map<String, String> contextMap;
    private final ThreadContext.ContextStack contextStack;
    private String threadName = null;
    private StackTraceElement source;
    private boolean includeLocation;
    private boolean endOfBatch = false;

    public static class Builder implements org.apache.logging.log4j.core.util.Builder<LogEvent> {

        private String loggerFqcn;
        private Marker marker;
        private Level level;
        private String loggerName;
        private Message message;
        private Throwable thrown;

        public Builder setLoggerFqcn(final String loggerFqcn) {
            this.loggerFqcn = loggerFqcn;
            return this;
        }

        public Builder setMarker(final Marker marker) {
            this.marker = marker;
            return this;
        }

        public Builder setLevel(final Level level) {
            this.level = level;
            return this;
        }

        public Builder setLoggerName(final String loggerName) {
            this.loggerName = loggerName;
            return this;
        }

        public Builder setMessage(final Message message) {
            this.message = message;
            return this;
        }

        public Builder setThrown(final Throwable thrown) {
            this.thrown = thrown;
            return this;
        }

        @Override
        public Log4jLogEvent build() {
            return new Log4jLogEvent(loggerName, marker, loggerFqcn, level, message, thrown);
        }
    }

    public static Builder newBuilder() {
        return new Builder();
    }

    public Log4jLogEvent() {
        this(clock.currentTimeMillis());
    }

    /**
     *
     */
    public Log4jLogEvent(final long timestamp) {
        this(Strings.EMPTY, null, Strings.EMPTY, null, null, (Throwable) null, null, null, null, null, timestamp);
    }

    /**
     * Constructor.
     * @param loggerName The name of the Logger.
     * @param marker The Marker or null.
     * @param loggerFQCN The fully qualified class name of the caller.
     * @param level The logging Level.
     * @param message The Message.
     * @param t A Throwable or null.
     */
    public Log4jLogEvent(final String loggerName, final Marker marker, final String loggerFQCN, final Level level,
                         final Message message, final Throwable t) {
        this(loggerName, marker, loggerFQCN, level, message, null, t);
    }

    /**
     * Constructor.
     * @param loggerName The name of the Logger.
     * @param marker The Marker or null.
     * @param loggerFQCN The fully qualified class name of the caller.
     * @param level The logging Level.
     * @param message The Message.
     * @param properties properties to add to the event.
     * @param t A Throwable or null.
     */
    public Log4jLogEvent(final String loggerName, final Marker marker, final String loggerFQCN, final Level level,
                         final Message message, final List<Property> properties, final Throwable t) {
        this(loggerName, marker, loggerFQCN, level, message, t,
            createMap(properties),
            ThreadContext.getDepth() == 0 ? null : ThreadContext.cloneStack(), null,
            null,
            // LOG4J2-628 use log4j.Clock for timestamps
            // LOG4J2-744 unless TimestampMessage already has one
            message instanceof TimestampMessage ? ((TimestampMessage) message).getTimestamp() :
                clock.currentTimeMillis());
    }

    /**
     * Constructor.
     * @param loggerName The name of the Logger.
     * @param marker The Marker or null.
     * @param loggerFQCN The fully qualified class name of the caller.
     * @param level The logging Level.
     * @param message The Message.
     * @param t A Throwable or null.
     * @param mdc The mapped diagnostic context.
     * @param ndc the nested diagnostic context.
     * @param threadName The name of the thread.
     * @param location The locations of the caller.
     * @param timestamp The timestamp of the event.
     */
    public Log4jLogEvent(final String loggerName, final Marker marker, final String loggerFQCN, final Level level,
                         final Message message, final Throwable t, final Map<String, String> mdc,
                         final ThreadContext.ContextStack ndc, final String threadName,
                         final StackTraceElement location, final long timestamp) {
        this(loggerName, marker, loggerFQCN, level, message, t, null, mdc, ndc, threadName,
                location, timestamp);
    }

    /**
     * Create a new LogEvent.
     * @param loggerName The name of the Logger.
     * @param marker The Marker or null.
     * @param loggerFQCN The fully qualified class name of the caller.
     * @param level The logging Level.
     * @param message The Message.
     * @param thrown A Throwable or null.
     * @param thrownProxy A ThrowableProxy or null.
     * @param mdc The mapped diagnostic context.
     * @param ndc the nested diagnostic context.
     * @param threadName The name of the thread.
     * @param location The locations of the caller.
     * @param timestamp The timestamp of the event.
     */
    public static Log4jLogEvent createEvent(final String loggerName, final Marker marker, final String loggerFQCN,
                                            final Level level, final Message message, final Throwable thrown, 
                                            final ThrowableProxy thrownProxy,
                                            final Map<String, String> mdc, final ThreadContext.ContextStack ndc,
                                            final String threadName, final StackTraceElement location,
                                            final long timestamp) {
        final Log4jLogEvent result = new Log4jLogEvent(loggerName, marker, loggerFQCN, level, message, thrown, 
                thrownProxy, mdc, ndc, threadName, location, timestamp);
        return result;
    }

    /**
     * Constructor.
     * @param loggerName The name of the Logger.
     * @param marker The Marker or null.
     * @param loggerFQCN The fully qualified class name of the caller.
     * @param level The logging Level.
     * @param message The Message.
     * @param thrown A Throwable or null.
     * @param thrownProxy A ThrowableProxy or null.
     * @param contextMap The mapped diagnostic context.
     * @param contextStack the nested diagnostic context.
     * @param threadName The name of the thread.
     * @param source The locations of the caller.
     * @param timestamp The timestamp of the event.
     */
    private Log4jLogEvent(final String loggerName, final Marker marker, final String loggerFQCN, final Level level,
            final Message message, final Throwable thrown, final ThrowableProxy thrownProxy, 
            final Map<String, String> contextMap, final ThreadContext.ContextStack contextStack, 
            final String threadName, final StackTraceElement source, final long timestamp) {
        this.loggerName = loggerName;
        this.marker = marker;
        this.loggerFqcn = loggerFQCN;
        this.level = (level == null) ? Level.OFF : level; // LOG4J2-462, LOG4J2-465
        this.message = message;
        this.thrown = thrown;
        this.thrownProxy = thrownProxy;
        this.contextMap = contextMap == null ? ThreadContext.EMPTY_MAP : contextMap;
        this.contextStack = contextStack == null ? ThreadContext.EMPTY_STACK : contextStack;
        this.timeMillis = message instanceof TimestampMessage ? ((TimestampMessage) message).getTimestamp() : timestamp;
        this.threadName = threadName;
        this.source = source;
        if (message != null && message instanceof LoggerNameAwareMessage) {
            ((LoggerNameAwareMessage) message).setLoggerName(loggerName);
        }
    }

    private static Map<String, String> createMap(final List<Property> properties) {
        final Map<String, String> contextMap = ThreadContext.getImmutableContext();
        if (contextMap == null && (properties == null || properties.isEmpty())) {
            return null;
        }
        if (properties == null || properties.isEmpty()) {
            return contextMap; // contextMap is not null
        }
        final Map<String, String> map = new HashMap<String, String>(contextMap);

        for (final Property prop : properties) {
            if (!map.containsKey(prop.getName())) {
                map.put(prop.getName(), prop.getValue());
            }
        }
        return Collections.unmodifiableMap(map);
    }

    /**
     * Returns the logging Level.
     * @return the Level associated with this event.
     */
    @Override
    public Level getLevel() {
        return level;
    }

    /**
     * Returns the name of the Logger used to generate the event.
     * @return The Logger name.
     */
    @Override
    public String getLoggerName() {
        return loggerName;
    }

    /**
     * Returns the Message associated with the event.
     * @return The Message.
     */
    @Override
    public Message getMessage() {
        return message;
    }

    /**
     * Returns the name of the Thread on which the event was generated.
     * @return The name of the Thread.
     */
    @Override
    public String getThreadName() {
        if (threadName == null) {
            threadName = Thread.currentThread().getName();
        }
        return threadName;
    }

    /**
     * Returns the time in milliseconds from the epoch when the event occurred.
     * @return The time the event occurred.
     */
    @Override
    public long getTimeMillis() {
        return timeMillis;
    }

    /**
     * Returns the Throwable associated with the event, or null.
     * @return The Throwable associated with the event.
     */
    @Override
    public Throwable getThrown() {
        return thrown;
    }

    /**
     * Returns the ThrowableProxy associated with the event, or null.
     * @return The ThrowableProxy associated with the event.
     */
    @Override
    public ThrowableProxy getThrownProxy() {
        if (thrownProxy == null && thrown != null) {
            thrownProxy = new ThrowableProxy(thrown);
        }
        return thrownProxy;
    }


    /**
     * Returns the Marker associated with the event, or null.
     * @return the Marker associated with the event.
     */
    @Override
    public Marker getMarker() {
        return marker;
    }

    /**
     * The fully qualified class name of the class that was called by the caller.
     * @return the fully qualified class name of the class that is performing logging.
     */
    @Override
    public String getLoggerFqcn() {
        return loggerFqcn;
    }

    /**
     * Returns the immutable copy of the ThreadContext Map.
     * @return The context Map.
     */
    @Override
    public Map<String, String> getContextMap() {
        return contextMap;
    }

    /**
     * Returns an immutable copy of the ThreadContext stack.
     * @return The context Stack.
     */
    @Override
    public ThreadContext.ContextStack getContextStack() {
        return contextStack;
    }

    /**
     * Returns the StackTraceElement for the caller. This will be the entry that occurs right
     * before the first occurrence of FQCN as a class name.
     * @return the StackTraceElement for the caller.
     */
    @Override
    public StackTraceElement getSource() {
        if (source != null) {
            return source;
        }
        if (loggerFqcn == null || !includeLocation) {
            return null;
        }
        source = calcLocation(loggerFqcn);
        return source;
    }

    public static StackTraceElement calcLocation(final String fqcnOfLogger) {
        if (fqcnOfLogger == null) {
            return null;
        }
        final StackTraceElement[] stackTrace = Thread.currentThread().getStackTrace();
        StackTraceElement last = null;
        for (int i = stackTrace.length - 1; i > 0; i--) {
            final String className = stackTrace[i].getClassName();
            if (fqcnOfLogger.equals(className)) {
                return last;
            }
            last = stackTrace[i];
        }
        return null;
    }

    @Override
    public boolean isIncludeLocation() {
        return includeLocation;
    }

    @Override
    public void setIncludeLocation(final boolean includeLocation) {
        this.includeLocation = includeLocation;
    }

    @Override
    public boolean isEndOfBatch() {
        return endOfBatch;
    }

    @Override
    public void setEndOfBatch(final boolean endOfBatch) {
        this.endOfBatch = endOfBatch;
    }

    /**
     * Creates a LogEventProxy that can be serialized.
     * @return a LogEventProxy.
     */
    protected Object writeReplace() {
        getThrownProxy(); // ensure ThrowableProxy is initialized
        return new LogEventProxy(this, this.includeLocation);
    }

    public static Serializable serialize(final Log4jLogEvent event,
            final boolean includeLocation) {
        event.getThrownProxy(); // ensure ThrowableProxy is initialized
        return new LogEventProxy(event, includeLocation);
    }

    public static boolean canDeserialize(final Serializable event) {
        return event instanceof LogEventProxy;
    }

    public static Log4jLogEvent deserialize(final Serializable event) {
        if (event == null) {
            throw new NullPointerException("Event cannot be null");
        }
        if (event instanceof LogEventProxy) {
            final LogEventProxy proxy = (LogEventProxy) event;
            final Log4jLogEvent result = new Log4jLogEvent(proxy.loggerName, proxy.marker,
                    proxy.loggerFQCN, proxy.level, proxy.message,
                    proxy.thrown, proxy.thrownProxy, proxy.contextMap, proxy.contextStack, proxy.threadName,
                    proxy.source, proxy.timeMillis);
            result.setEndOfBatch(proxy.isEndOfBatch);
            result.setIncludeLocation(proxy.isLocationRequired);
            return result;
        }
        throw new IllegalArgumentException("Event is not a serialized LogEvent: " + event.toString());
    }

    private void readObject(final ObjectInputStream stream) throws InvalidObjectException {
        throw new InvalidObjectException("Proxy required");
    }

    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder();
        final String n = loggerName.isEmpty() ? "root" : loggerName;
        sb.append("Logger=").append(n);
        sb.append(" Level=").append(level.name());
        sb.append(" Message=").append(message.getFormattedMessage());
        return sb.toString();
    }

    @Override
    public boolean equals(final Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }

        final Log4jLogEvent that = (Log4jLogEvent) o;

        if (endOfBatch != that.endOfBatch) {
            return false;
        }
        if (includeLocation != that.includeLocation) {
            return false;
        }
        if (timeMillis != that.timeMillis) {
            return false;
        }
        if (loggerFqcn != null ? !loggerFqcn.equals(that.loggerFqcn) : that.loggerFqcn != null) {
            return false;
        }
        if (level != null ? !level.equals(that.level) : that.level != null) {
            return false;
        }
        if (source != null ? !source.equals(that.source) : that.source != null) {
            return false;
        }
        if (marker != null ? !marker.equals(that.marker) : that.marker != null) {
            return false;
        }
        if (contextMap != null ? !contextMap.equals(that.contextMap) : that.contextMap != null) {
            return false;
        }
        if (!message.equals(that.message)) {
            return false;
        }
        if (!loggerName.equals(that.loggerName)) {
            return false;
        }
        if (contextStack != null ? !contextStack.equals(that.contextStack) : that.contextStack != null) {
            return false;
        }
        if (threadName != null ? !threadName.equals(that.threadName) : that.threadName != null) {
            return false;
        }
        if (thrown != null ? !thrown.equals(that.thrown) : that.thrown != null) {
            return false;
        }
        if (thrownProxy != null ? !thrownProxy.equals(that.thrownProxy) : that.thrownProxy != null) {
            return false;
        }

        return true;
    }

    @Override
    public int hashCode() {
        int result = loggerFqcn != null ? loggerFqcn.hashCode() : 0;
        result = 31 * result + (marker != null ? marker.hashCode() : 0);
        result = 31 * result + (level != null ? level.hashCode() : 0);
        result = 31 * result + loggerName.hashCode();
        result = 31 * result + message.hashCode();
        result = 31 * result + (int) (timeMillis ^ (timeMillis >>> 32));
        result = 31 * result + (thrown != null ? thrown.hashCode() : 0);
        result = 31 * result + (thrownProxy != null ? thrownProxy.hashCode() : 0);
        result = 31 * result + (contextMap != null ? contextMap.hashCode() : 0);
        result = 31 * result + (contextStack != null ? contextStack.hashCode() : 0);
        result = 31 * result + (threadName != null ? threadName.hashCode() : 0);
        result = 31 * result + (source != null ? source.hashCode() : 0);
        result = 31 * result + (includeLocation ? 1 : 0);
        result = 31 * result + (endOfBatch ? 1 : 0);
        return result;
    }

    /**
     * Proxy pattern used to serialize the LogEvent.
     */
    private static class LogEventProxy implements Serializable {

        private static final long serialVersionUID = -7139032940312647146L;
        private final String loggerFQCN;
        private final Marker marker;
        private final Level level;
        private final String loggerName;
        private final Message message;
        private final long timeMillis;
        private final transient Throwable thrown;
        private final ThrowableProxy thrownProxy;
        private final Map<String, String> contextMap;
        private final ThreadContext.ContextStack contextStack;
        private final String threadName;
        private final StackTraceElement source;
        private final boolean isLocationRequired;
        private final boolean isEndOfBatch;

        public LogEventProxy(final Log4jLogEvent event, final boolean includeLocation) {
            this.loggerFQCN = event.loggerFqcn;
            this.marker = event.marker;
            this.level = event.level;
            this.loggerName = event.loggerName;
            this.message = event.message;
            this.timeMillis = event.timeMillis;
            this.thrown = event.thrown;
            this.thrownProxy = event.thrownProxy;
            this.contextMap = event.contextMap;
            this.contextStack = event.contextStack;
            this.source = includeLocation ? event.getSource() : null;
            this.threadName = event.getThreadName();
            this.isLocationRequired = includeLocation;
            this.isEndOfBatch = event.endOfBatch;
        }

        /**
         * Returns a Log4jLogEvent using the data in the proxy.
         * @return Log4jLogEvent.
         */
        protected Object readResolve() {
            final Log4jLogEvent result = new Log4jLogEvent(loggerName, marker, loggerFQCN, level, message, thrown,
                    thrownProxy, contextMap, contextStack, threadName, source, timeMillis);
            result.setEndOfBatch(isEndOfBatch);
            result.setIncludeLocation(isLocationRequired);
            return result;
        }
    }
}