/*
 * $Id$
 *
 * Copyright 1996-2008 Sun Microsystems, Inc.  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.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */
package com.sun.javatest.lib;

import java.io.BufferedReader;
import java.io.File;
import java.io.InputStreamReader;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.Reader;
import java.util.Hashtable;


import com.sun.javatest.Command;
import com.sun.javatest.Status;
import com.sun.javatest.util.StringArray;

/**
 * A Command to execute an arbitrary OS command.
 **/
public class ProcessCommand extends Command
{
    /**
     * A stand-alone entry point for this command. An instance of this
     * command is created, and its <code>run</code> method invoked,
     * passing in the command line args and <code>System.out</code> and
     * <code>System.err</code> as the two streams.
     * @param args command line arguments for this command.
     * @see #run
     */
    public static void main(String[] args) {
	PrintWriter log = new PrintWriter(new OutputStreamWriter(System.err));
	PrintWriter ref = new PrintWriter(new OutputStreamWriter(System.out));
	Status s;
	try {
	    Command cmd = new ProcessCommand();
	    s = cmd.run(args, log, ref);
	}
	finally {
	    log.flush();
	    ref.flush();
	}
	s.exit();
    }

    /**
     * Set a status to be returned for a specific exit code, overwriting any
     * previous setting for this exit code. If the default status has not yet 
     * been initialized, it is set to Status.error("unrecognized exit code").
     *
     * @param exitCode The process exit code for which to assign a status.
     * @param status The status to associate with the exit code.
     */
    public void setStatusForExit(int exitCode, Status status) {
	if (statusTable == null) {
	    statusTable = new Hashtable();
	    if (defaultStatus == null)
		defaultStatus = Status.error("unrecognized exit code");
	}
	statusTable.put(new Integer(exitCode), status);
    }

    /**
     * Set the default status to be returned for all exit codes. 
     * This will not affect any values for specific exit codes that 
     * may have been set with setStatusForExit. If this method is
     * not called, the default value will be Status.failed (for
     * backwards compatability) unless setStatusForExit has been
     * called, which sets the default value to Status.error.  
     *
     * @param status The default status to use when a specific status
     * has not been set for a particular process exit code.
     */ 
    public void setDefaultStatus(Status status) {
	if (statusTable == null) 
	    statusTable = new Hashtable();
	defaultStatus = status;
    }

    /**
     * Set the directory in which to execute the process.
     * Use null to indicate the default directory.
     * @param dir the directory in which to execute the process.
     * @see #getExecDir
     */
    public void setExecDir(File dir) {
	execDir = dir;
    }

    /**
     * Get the directory in which to execute the process,
     * or null if none set.
     * @return the directory in which to execute the process.
     * @see #setExecDir
     */
    public File getExecDir() {
	return execDir;
    } 

    /**
     * Internal routine to assist argument decoding prior to calling
     * setStatusForExit or setDefaultStatus
     */
    private void setStatus(String exitSpec, Status status) {
	// for now, we just support "default" and <integer>
	// in principle we could support ranges and lists too
	if (exitSpec.equals("default"))
	    setDefaultStatus(status);
	else 
	    setStatusForExit(Integer.parseInt(exitSpec), status);
    }

    /**
     * Run the given command.
     * @param args	An array of strings composed of
     * 			<em>command-options</em>,
     *			<em>environment-variables</em>,
     *			<em>command</em>,
     *			<em>command-arguments</em>.
     *			<br>
     *
     *			The <em>command-options</em> are an optional
     *			set of options, each beginning with `-', to be
     *			used by this object.
     *			The options are
     *			<dt>
     *			<dt>-v   
     *		       	<dd>	verbose mode
     *			<dt>-pass|-fail|-error <i>exit-code</i> <i>string</i>
     *			<dd>	set the status to be returned for the given 
     *				exit code to one of 
     *				Status.passed/Status.failed/Status.error.
     *				<i>exit-code</i> can be either an integer or "default".
     *				<i>string</i> the message string provided in the
     *				status object.
     *                  <dt>-execDir <i>execDir</i>
     *			<dd>    set the directory in which to execute the command.
     *			</dl>
     *			<br>
     *			
     *			The <em>environment-variables</em> are an
     *			optional list of environment variable to be supplied
     *			to the command. They should be in the form
     *			<em>NAME</em><code>=</code><em>VALUE</em>.
     *			<br>
     *
     *			The <em>command</em> identifies the command to
     *			be executed. This name will be platform specific.
     *			<br>
     *
     *			The <em>command-arguments</em> are an optional
     *			list of strings to be passed to the command to be
     *			executed.
     * @param log	A stream for logging output.
     * @param ref	A stream for reference output, if the test requires it.
     *			If not, it can be used as an additional logging stream.
     *
     * @return 		The result of the method is obtained by calling
     *			<code>getStatus</code> after the command completes.
     *			The default behaviour is to use the explicit or default
     *			status given in the arguments, or via the API. If none
     *			have been set up, then the following values are used:
     *			<code>Status.passed("exit code 0")</code>
     *			if the command exited with exit status 0, or
     *			<code>Status.failed("exit code " + exitCode)</code>
     *			otherwise.  <code>getStatus</code> may be overridden
     *			to provide different behavior.
     *
     * @see #getStatus
     *
     **/
    public Status run(String[] args, PrintWriter log, PrintWriter ref) {
	// analyse options
	int i = 0;
	for (; i < args.length && args[i].startsWith("-"); i++) {
	    if (args[i].equals("-v"))
	    	verbose = true;
	    else if (args[i].equals("-execDir") && i+1 < args.length) {
		execDir = new File(args[++i]);
	    }
	    else if (args[i].equals("-pass") && i+2 < args.length) {
		setStatus(args[++i], Status.passed(args[++i]));
	    }
	    else if (args[i].equals("-fail") && i+2 < args.length) {
		setStatus(args[++i], Status.failed(args[++i]));
	    }
	    else if (args[i].equals("-error") && i+2 < args.length) {
		setStatus(args[++i], Status.error(args[++i]));
	    }
	    else if (args[i].equals("-end")) { 
		// -end is supported for the improbable event someone wants an 
		// env var or command beginning with -
		i++;  // because the for-loop won't get a chance to do it
		break;
	    }
	    else
		return Status.error("Unrecognized option: " + args[i]);
	}

	// get environment variables for command
	int cmdEnvStart = i;
	while (i < args.length && (args[i].indexOf('=') != -1))
	    i++;
	String[] cmdEnv = new String[i - cmdEnvStart];
	System.arraycopy(args, cmdEnvStart, cmdEnv, 0, cmdEnv.length);

	// get command name
	if (i == args.length)
	    return Status.error("no command specified for " + getClass().getName());

	String[] cmd = new String[args.length - i];
	System.arraycopy(args, i, cmd, 0, cmd.length);

	return exec(cmd, cmdEnv, log, ref);
    }

    /**
     * Exceute a command, bypassing the standard argument decoding of 'run'.
     * @param cmd       The command to be executed
     * @param cmdEnv    The environment to be passed to the command
     * @param log	A stream for logging output.
     * @param ref	A stream for reference output, if the test requires it.
     *			If not, it can be used as an additional logging stream.
     * @return 		The result of the method is obtained by calling
     *			<code>getStatus</code> after the command completes.
     * @see #run
     * @see #getStatus
     */
    public Status exec(String[] cmd, String[] cmdEnv, PrintWriter log, PrintWriter ref) {
	Process p = null;
	Status s = null;
	try {
	    // The following is a workaround for a JDK problem ... if the cmdEnv
	    // is empty, JDK assumes this means to inherit the parent environment.
	    // (There is a separate call which more reasonably means that.)
	    // So, to prevent the parent process' environment being inherited
	    // we set the command environment to a dummy entry which will hopefully
	    // not cause any problems for either the Runtime machinery or the
	    // child process.
	    if (cmdEnv != null && cmdEnv.length == 0) {
		String[] envWithDummyEntry = {/*empty*/"="/*empty*/};
		cmdEnv=envWithDummyEntry;
	    }

	    if (verbose) {
		log.println("Command is: " + StringArray.join(cmd));
		if (cmdEnv == null) {
		    log.println("Command environment is inherited from parent process");
		}
		else if (cmdEnv.length == 0) {
		    log.println("Command environment is empty");
		}
		else {
		    log.println("Command environment is:");
		    for (int i = 0; i < cmdEnv.length; i++)
			log.println(cmdEnv[i]);
		}
		if (execDir != null)
		    log.println("Execution directory is " + execDir);
	    }

	    Runtime r = Runtime.getRuntime();
	    p = (execDir == null ? r.exec(cmd, cmdEnv) : r.exec(cmd, cmdEnv, execDir));

	    Reader in = new InputStreamReader(p.getInputStream()); // output stream from process
	    StreamCopier refConnector = new StreamCopier(in, ref);
	    refConnector.start();
	    Reader err = new InputStreamReader(p.getErrorStream());
	    StreamCopier logConnector = new StreamCopier(err, log);
	    logConnector.start();

	    OutputStream out = p.getOutputStream();  // input stream to process
	    if (out != null)
		out.close();

	    // wait for the stream copiers to complete (which may be interrupted by the
	    // timeout thread
	    refConnector.waitUntilDone();
	    logConnector.waitUntilDone();

	    // wait for the process to complete;
	    // WARNING: in JDK1.0.2 this does not appear to be interruptible, which is
	    // why we waited for the stream copiers to complete first ... because they are
	    // interruptible.
	    int exitCode = p.waitFor();
	    //if (verbose > 0)
	    //	log.report("command exited, exit=" + exitCode);

	    in.close();
	    err.close();

	    return getStatus(exitCode, logConnector.exitStatus());
	}
	catch (InterruptedException e) {
	    if (p != null)
		p.destroy();
	    String msg = "Program `" + cmd[0] + "' interrupted! (timed out?)";
	    s = (useFailedOnException ? Status.failed(msg) : Status.error(msg));
	}
	catch (IOException e) {
	    String msg = "Error invoking program `" + cmd[0] + "': " + e;
	    s = (useFailedOnException ? Status.failed(msg) : Status.error(msg));
	}
	return s;
    }

    /**
     * Generate a status for the command, based upon the command's exit code
     * and a status that may have been passed from the command by using
     * <code>status.exit()</code>.
     *
     * @param exitCode		The exit code from the command that was executed.
     * @param logStatus		If the command that was executed was a test program
     *				and exited by calling <code>status.exit()</code>,
     *				then logStatus will be set to `status'.  Otherwise,
     *				it will be null.  The value of the status is passed
     *				from the command by writing it as the last line to
     *				stdout before exiting the process.   If it is not
     *				received as the last line, the value will be lost.
     * @return		Unless overridden, the default is
     *			<code>Status.passed("exit code 0")</code>
     *			if the command exited with exit code 0, or
     *			<code>Status.failed("exit code " + exitCode)</code>
     *			otherwise.
     **/
    protected Status getStatus(int exitCode, Status logStatus) {
	if (logStatus != null)
	    return logStatus;
	else if (statusTable != null) {
	    Status s = (Status)(statusTable.get(new Integer(exitCode)));
	    return (s == null ? defaultStatus.augment("exit code: " + exitCode) : s);
	}
	else if (exitCode == 0)
	    return Status.passed("exit code 0");
	else
	    return Status.failed("exit code " + exitCode);
    }

    private boolean verbose;


    /**
     * A thread to copy an input stream to an output stream
     */
    class StreamCopier extends Thread
    {
	/**
	 * Create one.
	 * @param from 	the stream to copy from
	 * @param out	the log to copy to
	 */
	StreamCopier(Reader from, PrintWriter to) {
	    super(Thread.currentThread().getName() + "_StreamCopier_" + (serial++));
	    in = new BufferedReader(from);
	    out = to;
	    lastStatusLine = null;
	}

	/**
	 * Set the thread going.
	 */
	public void run() {
	    //System.out.println("Copying stream");
	    try {
		String line;
		while ((line = in.readLine()) != null) {
		    out.println(line);
		    // take care lastLine doesn't get set to null at EOF
		    // and ignore trailing newlines
		    if (line.startsWith(Status.EXIT_PREFIX))
			lastStatusLine = line;
		}
	    }
	    catch (IOException e) {
	    }
	    //System.out.println("Stream copied");
	    synchronized (this) {
		done = true;
		notifyAll();
	    }
	}

	public synchronized boolean isDone() {
	    return done;
	}

	/**
	 * Blocks until the copy is complete, or until the thread is interrupted
	 */
	public synchronized void waitUntilDone() throws InterruptedException {
	    boolean interrupted = false;

	    // poll interrupted flag, while waiting for copy to complete
	    while (!(interrupted = Thread.interrupted()) && !done)
		wait(1000);

	    //if (interrupted)
	    //    System.out.println("TESTSCRIPT DETECTS interrupted() " + Thread.currentThread().getName());
	    //else
	    //    System.out.println("TESTSCRIPT waitUntilDone OK " + Thread.currentThread().getName());

	    // workaround; if the exception hasn't been thrown already, do it now
	    if (interrupted) {
		//System.out.println("Stream copier: throwing InterruptedException");
		throw new InterruptedException();
	    }
	}

	/**
	 * Return the status information from the child process if it returned
	 * any on the log stream, otherwise return null.
	 */
	public Status exitStatus() {
	    if (lastStatusLine == null)
		return null;
	    else
		return Status.parse(lastStatusLine.substring(Status.EXIT_PREFIX.length()));
	}


	private BufferedReader in;
	private PrintWriter out;
	private String lastStatusLine;
	private boolean done;

    }

    private static boolean useFailedOnException = 
	Boolean.getBoolean("javatest.processCommand.useFailedOnException");
	
    private static int serial;
    private Hashtable statusTable;
    private Status defaultStatus;
    private File execDir;
}