/*
 * Copyright (c) 2013, 2015, 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.
 *
 * 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
 * questions.
 */

package jdk.test.lib;

import static jdk.test.lib.Asserts.assertTrue;
import java.io.IOException;
import java.lang.reflect.Field;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.UnknownHostException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
import java.util.function.BooleanSupplier;
import java.util.concurrent.TimeUnit;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
import sun.misc.Unsafe;

/**
 * Common library for various test helper functions.
 */
public final class Utils {

    /**
     * Returns the sequence used by operating system to separate lines.
     */
    public static final String NEW_LINE = System.getProperty("line.separator");

    /**
     * Returns the value of 'test.vm.opts' system property.
     */
    public static final String VM_OPTIONS = System.getProperty("test.vm.opts", "").trim();

    /**
     * Returns the value of 'test.java.opts' system property.
     */
    public static final String JAVA_OPTIONS = System.getProperty("test.java.opts", "").trim();

    /**
     * Returns the value of 'test.src' system property.
     */
    public static final String TEST_SRC = System.getProperty("test.src", "").trim();

    private static Unsafe unsafe = null;

    /**
     * Defines property name for seed value.
     */
    public static final String SEED_PROPERTY_NAME = "jdk.test.lib.random.seed";

    /* (non-javadoc)
     * Random generator with (or without) predefined seed. Depends on
     * "jdk.test.lib.random.seed" property value.
     */
    private static volatile Random RANDOM_GENERATOR;

    /**
     * Contains the seed value used for {@link java.util.Random} creation.
     */
    public static final long SEED = Long.getLong(SEED_PROPERTY_NAME, new Random().nextLong());
    /**
    * Returns the value of 'test.timeout.factor' system property
    * converted to {@code double}.
    */
    public static final double TIMEOUT_FACTOR;
    static {
        String toFactor = System.getProperty("test.timeout.factor", "1.0");
        TIMEOUT_FACTOR = Double.parseDouble(toFactor);
    }

    /**
    * Returns the value of JTREG default test timeout in milliseconds
    * converted to {@code long}.
    */
    public static final long DEFAULT_TEST_TIMEOUT = TimeUnit.SECONDS.toMillis(120);

    private Utils() {
        // Private constructor to prevent class instantiation
    }

    /**
     * Returns the list of VM options.
     *
     * @return List of VM options
     */
    public static List<String> getVmOptions() {
        return Arrays.asList(safeSplitString(VM_OPTIONS));
    }

    /**
     * Returns the list of VM options with -J prefix.
     *
     * @return The list of VM options with -J prefix
     */
    public static List<String> getForwardVmOptions() {
        String[] opts = safeSplitString(VM_OPTIONS);
        for (int i = 0; i < opts.length; i++) {
            opts[i] = "-J" + opts[i];
        }
        return Arrays.asList(opts);
    }

    /**
     * Returns the default JTReg arguments for a jvm running a test.
     * This is the combination of JTReg arguments test.vm.opts and test.java.opts.
     * @return An array of options, or an empty array if no options.
     */
    public static String[] getTestJavaOpts() {
        List<String> opts = new ArrayList<String>();
        Collections.addAll(opts, safeSplitString(VM_OPTIONS));
        Collections.addAll(opts, safeSplitString(JAVA_OPTIONS));
        return opts.toArray(new String[0]);
    }

    /**
     * Returns the default JTReg arguments for a jvm running a test without
     * options that matches regular expressions in {@code filters}.
     * This is the combination of JTReg arguments test.vm.opts and test.java.opts.
     * @param filters Regular expressions used to filter out options.
     * @return An array of options, or an empty array if no options.
     */
    public static String[] getFilteredTestJavaOpts(String... filters) {
        String options[] = getTestJavaOpts();

        if (filters.length == 0) {
            return options;
        }

        List<String> filteredOptions = new ArrayList<String>(options.length);
        Pattern patterns[] = new Pattern[filters.length];
        for (int i = 0; i < filters.length; i++) {
            patterns[i] = Pattern.compile(filters[i]);
        }

        for (String option : options) {
            boolean matched = false;
            for (int i = 0; i < patterns.length && !matched; i++) {
                Matcher matcher = patterns[i].matcher(option);
                matched = matcher.find();
            }
            if (!matched) {
                filteredOptions.add(option);
            }
        }

        return filteredOptions.toArray(new String[filteredOptions.size()]);
    }

    /**
     * Combines given arguments with default JTReg arguments for a jvm running a test.
     * This is the combination of JTReg arguments test.vm.opts and test.java.opts
     * @return The combination of JTReg test java options and user args.
     */
    public static String[] addTestJavaOpts(String... userArgs) {
        List<String> opts = new ArrayList<String>();
        Collections.addAll(opts, getTestJavaOpts());
        Collections.addAll(opts, userArgs);
        return opts.toArray(new String[0]);
    }

    /**
     * Splits a string by white space.
     * Works like String.split(), but returns an empty array
     * if the string is null or empty.
     */
    private static String[] safeSplitString(String s) {
        if (s == null || s.trim().isEmpty()) {
            return new String[] {};
        }
        return s.trim().split("\\s+");
    }

    /**
     * @return The full command line for the ProcessBuilder.
     */
    public static String getCommandLine(ProcessBuilder pb) {
        StringBuilder cmd = new StringBuilder();
        for (String s : pb.command()) {
            cmd.append(s).append(" ");
        }
        return cmd.toString();
    }

    /**
     * Returns the free port on the local host.
     * The function will spin until a valid port number is found.
     *
     * @return The port number
     * @throws InterruptedException if any thread has interrupted the current thread
     * @throws IOException if an I/O error occurs when opening the socket
     */
    public static int getFreePort() throws InterruptedException, IOException {
        int port = -1;

        while (port <= 0) {
            Thread.sleep(100);

            ServerSocket serverSocket = null;
            try {
                serverSocket = new ServerSocket(0);
                port = serverSocket.getLocalPort();
            } finally {
                serverSocket.close();
            }
        }

        return port;
    }

    /**
     * Returns the name of the local host.
     *
     * @return The host name
     * @throws UnknownHostException if IP address of a host could not be determined
     */
    public static String getHostname() throws UnknownHostException {
        InetAddress inetAddress = InetAddress.getLocalHost();
        String hostName = inetAddress.getHostName();

        assertTrue((hostName != null && !hostName.isEmpty()),
                "Cannot get hostname");

        return hostName;
    }

    /**
     * Uses "jcmd -l" to search for a jvm pid. This function will wait
     * forever (until jtreg timeout) for the pid to be found.
     * @param key Regular expression to search for
     * @return The found pid.
     */
    public static int waitForJvmPid(String key) throws Throwable {
        final long iterationSleepMillis = 250;
        System.out.println("waitForJvmPid: Waiting for key '" + key + "'");
        System.out.flush();
        while (true) {
            int pid = tryFindJvmPid(key);
            if (pid >= 0) {
                return pid;
            }
            Thread.sleep(iterationSleepMillis);
        }
    }

    /**
     * Searches for a jvm pid in the output from "jcmd -l".
     *
     * Example output from jcmd is:
     * 12498 sun.tools.jcmd.JCmd -l
     * 12254 /tmp/jdk8/tl/jdk/JTwork/classes/com/sun/tools/attach/Application.jar
     *
     * @param key A regular expression to search for.
     * @return The found pid, or -1 if not found.
     * @throws Exception If multiple matching jvms are found.
     */
    public static int tryFindJvmPid(String key) throws Throwable {
        OutputAnalyzer output = null;
        try {
            JDKToolLauncher jcmdLauncher = JDKToolLauncher.create("jcmd");
            jcmdLauncher.addToolArg("-l");
            output = ProcessTools.executeProcess(jcmdLauncher.getCommand());
            output.shouldHaveExitValue(0);

            // Search for a line starting with numbers (pid), follwed by the key.
            Pattern pattern = Pattern.compile("([0-9]+)\\s.*(" + key + ").*\\r?\\n");
            Matcher matcher = pattern.matcher(output.getStdout());

            int pid = -1;
            if (matcher.find()) {
                pid = Integer.parseInt(matcher.group(1));
                System.out.println("findJvmPid.pid: " + pid);
                if (matcher.find()) {
                    throw new Exception("Found multiple JVM pids for key: " + key);
                }
            }
            return pid;
        } catch (Throwable t) {
            System.out.println(String.format("Utils.findJvmPid(%s) failed: %s", key, t));
            throw t;
        }
    }

    /**
     * Return the contents of the named file as a single String,
     * or null if not found.
     * @param filename name of the file to read
     * @return String contents of file, or null if file not found.
     * @throws  IOException
     *          if an I/O error occurs reading from the file or a malformed or
     *          unmappable byte sequence is read
     */
    public static String fileAsString(String filename) throws IOException {
        Path filePath = Paths.get(filename);
        if (!Files.exists(filePath)) return null;
        return new String(Files.readAllBytes(filePath));
    }

    /**
     * @return Unsafe instance.
     */
    public static synchronized Unsafe getUnsafe() {
        if (unsafe == null) {
            try {
                Field f = Unsafe.class.getDeclaredField("theUnsafe");
                f.setAccessible(true);
                unsafe = (Unsafe) f.get(null);
            } catch (NoSuchFieldException | IllegalAccessException e) {
                throw new RuntimeException("Unable to get Unsafe instance.", e);
            }
        }
        return unsafe;
    }
    private static final char[] hexArray = new char[]{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};

    /**
     * Returns hex view of byte array
     *
     * @param bytes byte array to process
     * @return Space separated hexadecimal string representation of bytes
     */

    public static String toHexString(byte[] bytes) {
        char[] hexView = new char[bytes.length * 3];
        int i = 0;
        for (byte b : bytes) {
            hexView[i++] = hexArray[(b >> 4) & 0x0F];
            hexView[i++] = hexArray[b & 0x0F];
            hexView[i++] = ' ';
        }
        return new String(hexView);
    }

    /**
     * Returns {@link java.util.Random} generator initialized with particular seed.
     * The seed could be provided via system property {@link Utils#SEED_PROPERTY_NAME}
     * In case no seed is provided, the method uses a random number.
     * The used seed printed to stdout.
     * @return {@link java.util.Random} generator with particular seed.
     */
    public static Random getRandomInstance() {
        if (RANDOM_GENERATOR == null) {
            synchronized (Utils.class) {
                if (RANDOM_GENERATOR == null) {
                    RANDOM_GENERATOR = new Random(SEED);
                    System.out.printf("For random generator using seed: %d%n", SEED);
                    System.out.printf("To re-run test with same seed value please add \"-D%s=%d\" to command line.%n", SEED_PROPERTY_NAME, SEED);
                }
            }
        }
        return RANDOM_GENERATOR;
    }

    /**
     * Returns random element of non empty collection
     *
     * @param <T> a type of collection element
     * @param collection collection of elements
     * @return random element of collection
     * @throws IllegalArgumentException if collection is empty
     */
    public static <T> T getRandomElement(Collection<T> collection)
            throws IllegalArgumentException {
        if (collection.isEmpty()) {
            throw new IllegalArgumentException("Empty collection");
        }
        Random random = getRandomInstance();
        int elementIndex = 1 + random.nextInt(collection.size() - 1);
        Iterator<T> iterator = collection.iterator();
        while (--elementIndex != 0) {
            iterator.next();
        }
        return iterator.next();
    }

    /**
     * Wait for condition to be true
     *
     * @param condition, a condition to wait for
     */
    public static final void waitForCondition(BooleanSupplier condition) {
        waitForCondition(condition, -1L, 100L);
    }

    /**
     * Wait until timeout for condition to be true
     *
     * @param condition, a condition to wait for
     * @param timeout a time in milliseconds to wait for condition to be true
     * specifying -1 will wait forever
     * @return condition value, to determine if wait was successful
     */
    public static final boolean waitForCondition(BooleanSupplier condition,
            long timeout) {
        return waitForCondition(condition, timeout, 100L);
    }

    /**
     * Wait until timeout for condition to be true for specified time
     *
     * @param condition, a condition to wait for
     * @param timeout a time in milliseconds to wait for condition to be true,
     * specifying -1 will wait forever
     * @param sleepTime a time to sleep value in milliseconds
     * @return condition value, to determine if wait was successful
     */
    public static final boolean waitForCondition(BooleanSupplier condition,
            long timeout, long sleepTime) {
        long startTime = System.currentTimeMillis();
        while (!(condition.getAsBoolean() || (timeout != -1L
                && ((System.currentTimeMillis() - startTime) > timeout)))) {
            try {
                Thread.sleep(sleepTime);
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
                throw new Error(e);
            }
        }
        return condition.getAsBoolean();
    }

    /**
     * Adjusts the provided timeout value for the TIMEOUT_FACTOR
     * @param tOut the timeout value to be adjusted
     * @return The timeout value adjusted for the value of "test.timeout.factor"
     *         system property
     */
    public static long adjustTimeout(long tOut) {
        return Math.round(tOut * Utils.TIMEOUT_FACTOR);
    }

    /**
     * Ensures a requested class is loaded
     * @param aClass class to load
     */
    public static void ensureClassIsLoaded(Class<?> aClass) {
        if (aClass == null) {
            throw new Error("Requested null class");
        }
        try {
            Class.forName(aClass.getName(), /* initialize = */ true,
                    ClassLoader.getSystemClassLoader());
        } catch (ClassNotFoundException e) {
            throw new Error("Class not found", e);
        }
    }
    /**
     * Runs runnable and checks that it throws expected exception. If exceptionException is null it means
     * that we expect no exception to be thrown.
     * @param runnable what we run
     * @param expectedException expected exception
     */
    public static void runAndCheckException(Runnable runnable, Class<? extends Throwable> expectedException) {
        boolean expectedExceptionWasNotThrown = false;
        try {
            runnable.run();
            if (expectedException != null) {
                expectedExceptionWasNotThrown = true;
            }
        } catch (Throwable t) {
            if (expectedException == null) {
                throw new AssertionError("Got unexpected exception ", t);
            }
            if (!expectedException.isAssignableFrom(t.getClass())) {
                throw new AssertionError(String.format("Got unexpected exception %s instead of %s",
                        t.getClass().getSimpleName(), expectedException.getSimpleName()), t);
            }
        }
        if (expectedExceptionWasNotThrown) {
           throw new AssertionError("Didn't get expected exception " + expectedException.getSimpleName());
        }
    }

    /**
     * Converts to VM type signature
     *
     * @param type Java type to convert
     * @return string representation of VM type
     */
    public static String toJVMTypeSignature(Class<?> type) {
        if (type.isPrimitive()) {
            if (type == boolean.class) {
                return "Z";
            } else if (type == byte.class) {
                return "B";
            } else if (type == char.class) {
                return "C";
            } else if (type == double.class) {
                return "D";
            } else if (type == float.class) {
                return "F";
            } else if (type == int.class) {
                return "I";
            } else if (type == long.class) {
                return "J";
            } else if (type == short.class) {
                return "S";
            } else if (type == void.class) {
                return "V";
            } else {
                throw new Error("Unsupported type: " + type);
            }
        }
        String result = type.getName().replaceAll("\\.", "/");
        if (!type.isArray()) {
            return "L" + result + ";";
        }
        return result;
    }
}