/*
 * 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.gctests;

import com.google.monitoring.runtime.instrumentation.AllocationRecorder;
import com.google.monitoring.runtime.instrumentation.Sampler;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Marker;
import org.apache.logging.log4j.MarkerManager;
import org.apache.logging.log4j.ThreadContext;
import org.apache.logging.log4j.core.util.Constants;
import org.apache.logging.log4j.message.StringMapMessage;

import java.io.File;
import java.net.URL;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.regex.Pattern;

import static java.lang.System.getProperty;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertTrue;

/**
 * Utility methods for the GC-free logging tests.
 */
public enum GcFreeLoggingTestUtil {;

    public static void executeLogging(final String configurationFile,
                                      final Class<?> testClass) throws Exception {

        System.setProperty("log4j2.enable.threadlocals", "true");
        System.setProperty("log4j2.enable.direct.encoders", "true");
        System.setProperty("log4j2.is.webapp", "false");
        System.setProperty("log4j.configurationFile", configurationFile);

        assertTrue(Constants.ENABLE_THREADLOCALS, "Constants.ENABLE_THREADLOCALS");
        assertTrue(Constants.ENABLE_DIRECT_ENCODERS, "Constants.ENABLE_DIRECT_ENCODERS");
        assertFalse(Constants.IS_WEB_APP, "Constants.IS_WEB_APP");

        final MyCharSeq myCharSeq = new MyCharSeq();
        final Marker testGrandParent = MarkerManager.getMarker("testGrandParent");
        final Marker testParent = MarkerManager.getMarker("testParent").setParents(testGrandParent);
        final Marker test = MarkerManager.getMarker("test").setParents(testParent); // initial creation, value is cached

        // initialize LoggerContext etc.
        // This is not steady-state logging and will allocate objects.
        ThreadContext.put("aKey", "value1");
        ThreadContext.put("key2", "value2");

        final org.apache.logging.log4j.Logger logger = LogManager.getLogger(testClass.getName());
        logger.debug("debug not set");
        logger.fatal(test, "This message is logged to the console");
        logger.error("Sample error message");
        logger.error("Test parameterized message {}", "param");
        logger.error(new StringMapMessage().with("eventId", "Login")); // initialize GelfLayout's messageStringBuilder
        for (int i = 0; i < 256; i++) {
            logger.debug("ensure all ringbuffer slots have been used once"); // allocate MutableLogEvent.messageText
        }
        ThreadContext.remove("aKey");
        ThreadContext.remove("key2");

        // BlockingWaitStrategy uses ReentrantLock which allocates Node objects. Ignore this.
        final String[] exclude = new String[] {
                "java/util/concurrent/locks/AbstractQueuedSynchronizer$Node", //
                "com/google/monitoring/runtime/instrumentation/Sampler", //
        };
        final AtomicBoolean samplingEnabled = new AtomicBoolean(true);
        final Sampler sampler = new Sampler() {
            @Override
            public void sampleAllocation(final int count, final String desc, final Object newObj, final long size) {
                if (!samplingEnabled.get()) {
                    return;
                }
                for (int i = 0; i < exclude.length; i++) {
                    if (exclude[i].equals(desc)) {
                        return; // exclude
                    }
                }
                System.err.println("I just allocated the object " + newObj +
                        " of type " + desc + " whose size is " + size);
                if (count != -1) {
                    System.err.println("It's an array of size " + count);
                }

                // show a stack trace to see which line caused allocation
                new RuntimeException().printStackTrace();
            }
        };
        Thread.sleep(500);
        final StringMapMessage mapMessage = new StringMapMessage().with("eventId", "Login");
        AllocationRecorder.addSampler(sampler);

        // now do some steady-state logging

        ThreadContext.put("aKey", "value1");
        ThreadContext.put("key2", "value2");

        final int ITERATIONS = 5;
        for (int i = 0; i < ITERATIONS; i++) {
            logger.error(myCharSeq);
            logger.error(MarkerManager.getMarker("test"), myCharSeq);
            logger.error("Test message");
            logger.error("Test parameterized message {}", "param");
            logger.error("Test parameterized message {}{}", "param", "param2");
            logger.error("Test parameterized message {}{}{}", "param", "param2", "abc");
            logger.error(mapMessage); // LOG4J2-1683
            ThreadContext.remove("aKey");
            ThreadContext.put("aKey", "value1");
        }
        Thread.sleep(50);
        samplingEnabled.set(false); // reliably ignore all allocations from now on
        AllocationRecorder.removeSampler(sampler);
        Thread.sleep(100);
    }

    public static void runTest(final Class<?> cls) throws Exception {
        final String javaHome = getProperty("java.home");
        final String javaBin = javaHome + File.separator + "bin" + File.separator + "java";
        final String classpath = getProperty("java.class.path");
        final String javaagent = "-javaagent:" + agentJar();
        final String usePreciseClock = System.getProperty("log4j2.usePreciseClock");

        final File tempFile = File.createTempFile("allocations", ".txt");
        tempFile.deleteOnExit();
        List<String> command = new ArrayList<>();
        command.add(javaBin);
        command.add(javaagent);
        if (usePreciseClock != null) {
            command.add("-Dlog4j2.usePreciseClock=" + usePreciseClock);
        }
        command.add("-cp");
        command.add(classpath);
        command.add(cls.getName());
        final ProcessBuilder builder = new ProcessBuilder(command);
        builder.redirectError(ProcessBuilder.Redirect.to(tempFile));
        builder.redirectOutput(ProcessBuilder.Redirect.to(tempFile));
        final Process process = builder.start();
        process.waitFor();
        process.exitValue();

        final AtomicInteger lineCounter = new AtomicInteger(0);
        Files.lines(tempFile.toPath(), Charset.defaultCharset()).forEach(line -> {

            // Trim the line.
            line = line.trim();

            // Check the first line.
            final int lineNumber = lineCounter.incrementAndGet();
            if (lineNumber == 1) {
                final String className = cls.getSimpleName();
                final String firstLinePattern = String.format(
                        "^FATAL .*\\.%s %s",
                        className,
                        Pattern.quote("[main] value1 {aKey=value1, " +
                                "key2=value2, prop1=value1, prop2=value2} " +
                                "This message is logged to the console"));
                assertTrue(line.matches(firstLinePattern),
                        "pattern mismatch at line 1: " + line);
            }

            // Check the rest of the lines. We are looking for the messages written to System.err
            // in the sampleAllocation() method above in executeLogging().
            else {
                assertFalse(line.contains(" allocated ") || line.contains(" array "),
                        "(allocated|array) pattern matches at line " + lineNumber + ": " + line);
            }

        });

    }

    private static File agentJar() throws Exception {
        final String name = AllocationRecorder.class.getName();
        final URL url = AllocationRecorder.class.getResource("/" + name.replace('.', '/').concat(".class"));
        if (url == null) {
            throw new IllegalStateException("Could not find url for " + name);
        }
        final String temp = url.toString();
        final URL jarurl = new URL(temp.substring("jar:".length(), temp.indexOf('!')));
        return new File(jarurl.toURI());
    }

    public static class MyCharSeq implements CharSequence {
        final String seq = GcFreeLoggingTestUtil.class.toString();

        @Override
        public int length() {
            return seq.length();
        }

        @Override
        public char charAt(final int index) {
            return seq.charAt(index);
        }

        @Override
        public CharSequence subSequence(final int start, final int end) {
            return seq.subSequence(start, end);
        }

        @Override
        public String toString() {
            System.err.println("TEMP OBJECT CREATED!");
            throw new IllegalStateException("TEMP OBJECT CREATED!");
        }
    }
}