/*

* Copyright (c) 2007-2008 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

*

*/

package nokia.ant;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.io.OutputStreamWriter;

import java.io.PrintStream;

import java.io.Writer;

import java.util.Hashtable;

import java.util.Stack;

import java.util.Enumeration;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import org.apache.tools.ant.util.DOMElementWriter;

import org.apache.tools.ant.util.StringUtils;

import org.apache.tools.ant.*;

import org.apache.tools.ant.util.DateUtils;

import org.w3c.dom.Document;

import org.w3c.dom.Element;

import org.w3c.dom.Text;

/**

 * Generates a file in the current directory with

 * an XML description of what happened during a build.

 * The default filename is "log.xml", but this can be overridden

 * with the property <code>XmlLogger.file</code>.

 *

 * This implementation assumes in its sanity checking that only one

 * thread runs a particular target/task at a time. This is enforced

 * by the way that parallel builds and antcalls are done - and

 * indeed all but the simplest of tasks could run into problems

 * if executed in parallel.

 *

 * @see Project#addBuildListener(BuildListener)

 */

public class XmlLogger implements BuildLogger {

    /** XML element name for a build. */

    private static final String BUILD_TAG = "build";

    /** XML element name for a target. */

    private static final String TARGET_TAG = "target";

    /** XML element name for a task. */

    private static final String TASK_TAG = "task";

    /** XML element name for a message. */

    private static final String MESSAGE_TAG = "message";

    /** XML attribute name for a name. */

    private static final String NAME_ATTR = "name";

    /** XML attribute name for a time. */

    private static final String TIME_ATTR = "time";

    /** XML attribute name for a message priority. */

    private static final String PRIORITY_ATTR = "priority";

    /** XML attribute name for a file location. */

    private static final String LOCATION_ATTR = "location";

    /** XML attribute name for an error description. */

    private static final String ERROR_ATTR = "error";

    /** XML element name for a stack trace. */

    private static final String STACKTRACE_TAG = "stacktrace";

    /** DocumentBuilder to use when creating the document to start with. */

    private static DocumentBuilder builder = getDocumentBuilder();

    private int msgOutputLevel = Project.MSG_ERR;

    private PrintStream outStream;

    /** The complete log document for this build. */

    private Document doc = builder.newDocument();

    /** Mapping for when tasks started (Task to TimedElement). */

    private Hashtable tasks = new Hashtable();

    /** Mapping for when targets started (Task to TimedElement). */

    private Hashtable targets = new Hashtable();

    /**

     * Mapping of threads to stacks of elements

     * (Thread to Stack of TimedElement).

     */

    private Hashtable threadStacks = new Hashtable();

    /**

     * When the build started.

     */

    private TimedElement buildElement;

    /**

     *  Constructs a new BuildListener that logs build events to an XML file.

     */

    public XmlLogger() {

    }

    /**

     * Returns a default DocumentBuilder instance or throws an

     * ExceptionInInitializerError if it can't be created.

     *

     * @return a default DocumentBuilder instance.

     */

    private static DocumentBuilder getDocumentBuilder() {

        try {

            return DocumentBuilderFactory.newInstance().newDocumentBuilder();

        } catch (Exception exc) {

        }

    }

    /** Utility class representing the time an element started. */

    private static class TimedElement {

        /**

         * Start time in milliseconds

         * (as returned by <code>System.currentTimeMillis()</code>).

         */

        private long startTime;

        /** Element created at the start time. */

        private Element element;

        public String toString() {

            return element.getTagName() + ":" + element.getAttribute("name");

        }

    }

    /**

     * Fired when the build starts, this builds the top-level element for the

     * document and remembers the time of the start of the build.

     *

     * @param event Ignored.

     */

    public void buildStarted(BuildEvent event) {

        buildElement = new TimedElement();

        buildElement.startTime = System.currentTimeMillis();

        buildElement.element = doc.createElement(BUILD_TAG);

    }

    /**

     * Fired when the build finishes, this adds the time taken and any

     * error stacktrace to the build element and writes the document to disk.

     *

     * @param event An event with any relevant extra information.

     *              Will not be <code>null</code>.

     */

    public void buildFinished(BuildEvent event) {

        long totalTime = System.currentTimeMillis() - buildElement.startTime;

        buildElement.element.setAttribute(TIME_ATTR,

                DateUtils.formatElapsedTime(totalTime));

        if (event.getException() != null) {

            buildElement.element.setAttribute(ERROR_ATTR,

                    event.getException().toString());

            // print the stacktrace in the build file it is always useful...

            // better have too much info than not enough.

            Throwable t = event.getException();

            Text errText = doc.createCDATASection(StringUtils.getStackTrace(t));

            Element stacktrace = doc.createElement(STACKTRACE_TAG);

            stacktrace.appendChild(errText);

            buildElement.element.appendChild(stacktrace);

        }

        String outFilename = event.getProject().getProperty("XmlLogger.file");

        if (outFilename == null) {

            outFilename = "log.xml";

        }

        String xslUri

                = event.getProject().getProperty("ant.XmlLogger.stylesheet.uri");

        if (xslUri == null) {

            xslUri = "log.xsl";

        }

        Writer out = null;

        try {

            // specify output in UTF8 otherwise accented characters will blow

            // up everything

            OutputStream stream = outStream;

            if (stream == null) {

                stream = new FileOutputStream(outFilename);

            }

            out = new OutputStreamWriter(stream, "UTF8");

            out.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");

            if (xslUri.length() > 0) {

                out.write("<?xml-stylesheet type=\"text/xsl\" href=\""

                        + xslUri + "\"?>\n\n");

            }

            (new DOMElementWriter()).write(buildElement.element, out, 0, "\t");

            out.flush();

        } catch (IOException exc) {

        } finally {

            if (out != null) {

                try {

                    out.close();

                } catch (IOException e) {

                    e = null; // ignore

                }

            }

        }

        buildElement = null;

    }

    /**

     * Returns the stack of timed elements for the current thread.

     * @return the stack of timed elements for the current thread

     */

    private Stack getStack() {

        Stack threadStack = (Stack) threadStacks.get(Thread.currentThread());

        if (threadStack == null) {

            threadStack = new Stack();

            threadStacks.put(Thread.currentThread(), threadStack);

        }

        /* For debugging purposes uncomment:

        org.w3c.dom.Comment s = doc.createComment("stack=" + threadStack);

        buildElement.element.appendChild(s);

         */

        return threadStack;

    }

    /**

     * Fired when a target starts building, this pushes a timed element

     * for the target onto the stack of elements for the current thread,

     * remembering the current time and the name of the target.

     *

     * @param event An event with any relevant extra information.

     *              Will not be <code>null</code>.

     */

    public void targetStarted(BuildEvent event) {

    }

    /**

     * Fired when a target finishes building, this adds the time taken

     * and any error stacktrace to the appropriate target element in the log.

     *

     * @param event An event with any relevant extra information.

     *              Will not be <code>null</code>.

     */

    public void targetFinished(BuildEvent event) {

    }

    /**

     * Fired when a task starts building, this pushes a timed element

     * for the task onto the stack of elements for the current thread,

     * remembering the current time and the name of the task.

     *

     * @param event An event with any relevant extra information.

     *              Will not be <code>null</code>.

     */

    public void taskStarted(BuildEvent event) {

    }

    /**

     * Fired when a task finishes building, this adds the time taken

     * and any error stacktrace to the appropriate task element in the log.

     *

     * @param event An event with any relevant extra information.

     *              Will not be <code>null</code>.

     */

    public void taskFinished(BuildEvent event) {

    }

    /**

     * Get the TimedElement associated with a task.

     *

     * Where the task is not found directly, search for unknown elements which

     * may be hiding the real task

     */

    private TimedElement getTaskElement(Task task) {

        TimedElement element = (TimedElement) tasks.get(task);

        if (element != null) {

            return element;

        }

        for (Enumeration e = tasks.keys(); e.hasMoreElements();) {

            Task key = (Task) e.nextElement();

            if (key instanceof UnknownElement) {

                if (((UnknownElement) key).getTask() == task) {

                    return (TimedElement) tasks.get(key);

                }

            }

        }

        return null;

    }

    /**

     * Fired when a message is logged, this adds a message element to the

     * most appropriate parent element (task, target or build) and records

     * the priority and text of the message.

     *

     * @param event An event with any relevant extra information.

     *              Will not be <code>null</code>.

     */

    public void messageLogged(BuildEvent event) {

        int priority = event.getPriority();

        if (priority > msgOutputLevel) {

            return;

        }

        Element messageElement = doc.createElement(MESSAGE_TAG);

        String name = "debug";

        switch (event.getPriority()) {

            case Project.MSG_ERR:

                name = "error";

                break;

            case Project.MSG_WARN:

                name = "warn";

                break;

            case Project.MSG_INFO:

                name = "info";

                break;

            default:

                name = "debug";

                break;

        }

        messageElement.setAttribute(PRIORITY_ATTR, name);

        Throwable ex = event.getException();

        if (Project.MSG_DEBUG <= msgOutputLevel && ex != null) {

            Text errText = doc.createCDATASection(StringUtils.getStackTrace(ex));

            Element stacktrace = doc.createElement(STACKTRACE_TAG);

            stacktrace.appendChild(errText);

            buildElement.element.appendChild(stacktrace);

        }

        Text messageText = doc.createCDATASection(event.getMessage());

        messageElement.appendChild(messageText);

        TimedElement parentElement = null;

        Task task = event.getTask();

        Target target = event.getTarget();

        if (task != null) {

            parentElement = getTaskElement(task);

        }

        if (parentElement == null && target != null) {

            parentElement = (TimedElement) targets.get(target);

        }

        /*

        if (parentElement == null) {

            Stack threadStack

                    = (Stack) threadStacks.get(Thread.currentThread());

            if (threadStack != null) {

                if (!threadStack.empty()) {

                    parentElement = (TimedElement) threadStack.peek();

                }

            }

        }

        */

        if (parentElement != null) {

            parentElement.element.appendChild(messageElement);

        } else {

            buildElement.element.appendChild(messageElement);

        }

    }

    // -------------------------------------------------- BuildLogger interface

    /**

     * Set the logging level when using this as a Logger

     *

     * @param level the logging level -

     *        see {@link org.apache.tools.ant.Project#MSG_ERR Project}

     *        class for level definitions

     */

    public void setMessageOutputLevel(int level) {

        msgOutputLevel = level;

    }

    /**

     * Set the output stream to which logging output is sent when operating

     * as a logger.

     *

     * @param output the output PrintStream.

     */

    public void setOutputPrintStream(PrintStream output) {

        this.outStream = new PrintStream(output, true);

    }

    /**

     * Ignore emacs mode, as it has no meaning in XML format

     *

     * @param emacsMode true if logger should produce emacs compatible

     *        output

     */

    public void setEmacsMode(boolean emacsMode) {

    }

    /**

     * Ignore error print stream. All output will be written to

     * either the XML log file or the PrintStream provided to

     * setOutputPrintStream

     *

     * @param err the stream we are going to ignore.

     */

    public void setErrorPrintStream(PrintStream err) {

    }

}