/*

 * Copyright (c) 2014, 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

 * questions.

 */

import java.io.BufferedReader;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStreamReader;

import java.nio.file.Files;

import java.util.List;

import java.util.Objects;

import java.util.concurrent.TimeUnit;

import java.util.jar.Attributes;

import java.util.jar.JarEntry;

import java.util.jar.JarOutputStream;

import java.util.jar.Manifest;

import javax.tools.JavaCompiler;

import javax.tools.JavaFileObject;

import javax.tools.StandardJavaFileManager;

import javax.tools.ToolProvider;

/**

 * Utils class for compiling , creating jar file and executing a java command

 *

 * @author Raghu Nair

 */

public class JavaToolUtils {

    public static final long DEFAULT_WAIT_TIME = 10000;

    private JavaToolUtils() {

    }

    /**

     * Takes a list of files and compile these files into the working directory.

     *

     * @param files

     * @throws IOException

     */

    public static void compileFiles(List<File> files) throws IOException {

        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();

        try (StandardJavaFileManager fileManager = compiler.

                getStandardFileManager(null, null, null)) {

            Iterable<? extends JavaFileObject> compilationUnit

                    = fileManager.getJavaFileObjectsFromFiles(files);

            compiler.getTask(null, fileManager, null, null, null,

                    compilationUnit).call();

        }

    }

    /**

     * Create a jar file using the list of files provided.

     *

     * @param jar

     * @param files

     * @throws IOException

     */

    public static void createJar(File jar, List<File> files)

            throws IOException {

        Manifest manifest = new Manifest();

        manifest.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION,

                "1.0");

        try (JarOutputStream target = new JarOutputStream(

                new FileOutputStream(jar), manifest)) {

            for (File file : files) {

                add(file, target);

            }

        }

    }

    private static void add(File source, JarOutputStream target)

            throws IOException {

        Objects.requireNonNull(source, "source cannot be null");

        Objects.requireNonNull(target, "target cannot be null");

        // not tested against directories and from different path.

        String name = source.getName();

        if (source.isDirectory()) {

            if (!name.isEmpty()) {

                if (!name.endsWith("/")) {

                    name += "/";

                }

                JarEntry entry = new JarEntry(name);

                entry.setTime(source.lastModified());

                target.putNextEntry(entry);

                target.closeEntry();

            }

            for (File nestedFile : source.listFiles()) {

                add(nestedFile, target);

            }

            return;

        }

        System.out.println("Adding entry " + name);

        JarEntry entry = new JarEntry(name);

        entry.setTime(source.lastModified());

        target.putNextEntry(entry);

        Files.copy(source.toPath(), target);

        target.closeEntry();

    }

    /**

     * Runs java command with provided arguments. Caller should not pass java

     * command in the argument list.

     *

     * @param commands

     * @param waitTime time to wait for the command to exit in milli seconds

     * @return

     * @throws Exception

     */

    public static int runJava(List<String> commands,long waitTime)

            throws Exception {

        String java = System.getProperty("java.home") + "/bin/java";

        commands.add(0, java);

        String command = commands.toString().replace(",", " ");

        System.out.println("Executing the following command \n" + command);

        ProcessBuilder processBuilder = new ProcessBuilder(commands);

        final Process process = processBuilder.start();

        BufferedReader errorStream = new BufferedReader(

                new InputStreamReader(process.getErrorStream()));

        BufferedReader outStream = new BufferedReader(

                new InputStreamReader(process.getInputStream()));

        String errorLine;

        StringBuilder errors = new StringBuilder();

        String outLines;

        while ((errorLine = errorStream.readLine()) != null) {

            errors.append(errorLine).append("\n");

        }

        while ((outLines = outStream.readLine()) != null) {

            System.out.println(outLines);

        }

        errorLine = errors.toString();

        System.err.println(errorLine);

        process.waitFor(waitTime, TimeUnit.MILLISECONDS);

        int exitStatus = process.exitValue();

        if (exitStatus != 0 && errorLine != null && errorLine.isEmpty()) {

            throw new RuntimeException(errorLine);

        }

        return exitStatus;

    }

    /**

     * Runs java command with provided arguments. Caller should not pass java

     * command in the argument list.

     *

     * @param commands

     * @return

     * @throws Exception

     */

    public static int runJava(List<String> commands) throws Exception {

        return runJava(commands, DEFAULT_WAIT_TIME);

    }

    /**

     * Run any command

     * @param commands

     * @return

     * @throws Exception

     */

    public static int runCommand(List<String> commands) throws Exception {

        String command = commands.toString().replace(",", " ");

        System.out.println("Executing the following command \n" + command);

        ProcessBuilder processBuilder = new ProcessBuilder(commands);

        final Process process = processBuilder.start();

        BufferedReader errorStream = new BufferedReader(

                new InputStreamReader(process.getErrorStream()));

        BufferedReader outStream = new BufferedReader(

                new InputStreamReader(process.getInputStream()));

        String errorLine;

        StringBuilder errors = new StringBuilder();

        String outLines;

        while ((errorLine = errorStream.readLine()) != null) {

            errors.append(errorLine).append("\n");

        }

        while ((outLines = outStream.readLine()) != null) {

            System.out.println(outLines);

        }

        errorLine = errors.toString();

        System.err.println(errorLine);

        int exitStatus = process.exitValue();

        if (exitStatus != 0 && errorLine != null && errorLine.isEmpty()) {

            throw new RuntimeException(errorLine);

        }

        return exitStatus;

    }

}