/*
 * Copyright (c) 2013, 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 com.oracle.java.testlibrary;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.lang.management.ManagementFactory;
import java.lang.management.RuntimeMXBean;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collections;

import sun.management.VMManagement;

public final class ProcessTools {

  private ProcessTools() {
  }

  /**
   * Pumps stdout and stderr from running the process into a String.
   *
   * @param processHandler ProcessHandler to run.
   * @return Output from process.
   * @throws IOException If an I/O error occurs.
   */
  public static OutputBuffer getOutput(ProcessBuilder processBuilder) throws IOException {
    return getOutput(processBuilder.start());
  }

  /**
   * Pumps stdout and stderr the running process into a String.
   *
   * @param process Process to pump.
   * @return Output from process.
   * @throws IOException If an I/O error occurs.
   */
  public static OutputBuffer getOutput(Process process) throws IOException {
    ByteArrayOutputStream stderrBuffer = new ByteArrayOutputStream();
    ByteArrayOutputStream stdoutBuffer = new ByteArrayOutputStream();
    StreamPumper outPumper = new StreamPumper(process.getInputStream(), stdoutBuffer);
    StreamPumper errPumper = new StreamPumper(process.getErrorStream(), stderrBuffer);
    Thread outPumperThread = new Thread(outPumper);
    Thread errPumperThread = new Thread(errPumper);

    outPumperThread.setDaemon(true);
    errPumperThread.setDaemon(true);

    outPumperThread.start();
    errPumperThread.start();

    try {
      process.waitFor();
      outPumperThread.join();
      errPumperThread.join();
    } catch (InterruptedException e) {
      Thread.currentThread().interrupt();
      return null;
    }

    return new OutputBuffer(stdoutBuffer.toString(), stderrBuffer.toString());
  }

  /**
   * Get the process id of the current running Java process
   *
   * @return Process id
   */
  public static int getProcessId() throws Exception {

    // Get the current process id using a reflection hack
    RuntimeMXBean runtime = ManagementFactory.getRuntimeMXBean();
    Field jvm = runtime.getClass().getDeclaredField("jvm");

    jvm.setAccessible(true);
    VMManagement mgmt = (sun.management.VMManagement) jvm.get(runtime);

    Method pid_method = mgmt.getClass().getDeclaredMethod("getProcessId");

    pid_method.setAccessible(true);

    int pid = (Integer) pid_method.invoke(mgmt);

    return pid;
  }

  /**
   * Get platform specific VM arguments (e.g. -d64 on 64bit Solaris)
   *
   * @return String[] with platform specific arguments, empty if there are none
   */
  public static String[] getPlatformSpecificVMArgs() {
    String osName = System.getProperty("os.name");
    String dataModel = System.getProperty("sun.arch.data.model");

    if (osName.equals("SunOS") && dataModel.equals("64")) {
      return new String[] { "-d64" };
    }

    return new String[] {};
  }

  /**
   * Create ProcessBuilder using the java launcher from the jdk to be tested and
   * with any platform specific arguments prepended
   */
  public static ProcessBuilder createJavaProcessBuilder(String... command) throws Exception {
    String javapath = JDKToolFinder.getJDKTool("java");

    ArrayList<String> args = new ArrayList<>();
    args.add(javapath);
    Collections.addAll(args, getPlatformSpecificVMArgs());
    Collections.addAll(args, command);

    return new ProcessBuilder(args.toArray(new String[args.size()]));

  }

}
