/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License (the "License").

 * You may not use this file except in compliance with the License.

 *

 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

 * or http://www.opensolaris.org/os/licensing.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

 * If applicable, add the following below this CDDL HEADER, with the

 * fields enclosed by brackets "[]" replaced with your own identifying

 * information: Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 */

/*

 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 */

package org.opensolaris.os.vp.panel.common.control;

import java.util.*;

import java.util.concurrent.*;

import java.util.regex.Pattern;

import org.opensolaris.os.vp.util.misc.*;

public class Navigator {

    //

    // Static data

    //

    public static final String PATH_SEPARATOR = "/";

    public static final String PARENT_ID = "..";

    private static int instanceCounter = 0;

    //

    // Instance data

    //

    private Thread dispatchThread;

    private ThreadPoolExecutor threadPool;

    private LinkedList<Control> stack = new LinkedList<Control>();

    private NavigationListeners listeners = new NavigationListeners(false);

    //

    // Constructors

    //

    public Navigator() {

	    instanceCounter++);

	ThreadFactory factory =

	    new NamedThreadFactory(tName) {

		@Override

		public Thread newThread(Runnable r) {

		    dispatchThread = super.newThread(r);

		    return dispatchThread;

		}

	    };

	// Unbounded

	BlockingQueue<Runnable> queue = new LinkedBlockingQueue<Runnable>();

	// Use a thread pool with a single core thread to autmatically handle

	// uncaught exceptions and queued requests

	threadPool = new ThreadPoolExecutor(

	    1, 1, 10, TimeUnit.MINUTES, queue, factory);

	threadPool.allowCoreThreadTimeOut(true);

    }

    //

    // Navigator methods

    //

    /**

     * Adds a {@link NavigationListener} to be notified when navigation is

     * stopped and started.

     */

    public void addNavigationListener(NavigationListener l) {

	listeners.add(l);

    }

    /**

     * Runs the given {@code Runnable} asynchronously on this {@code

     * Navigator}'s navigation thread.	This thread is intended to be used

     * specifically for navigation; the given {@code Runnable} should thus be

     * limited to calling {@link #goTo(boolean,Control,Navigable...)} and

     * (briefly) handling any thrown exceptions.

     * <p/>

     * Note: If this method is called when the navigation thread is busy, the

     * given {@code Runnable} will be queued and run when the thread is

     * available.

     *

     * @param	    r

     *		    the {@code Runnable} to run and handle any resulting

     *		    exceptions

     */

    public void asyncExec(Runnable r) {

	threadPool.execute(r);

    }

    /**

     * Runs the given {@link NavRunnable} on this {@code Navigator}'s navigation

     * thread and waits for it to complete.  Any exceptions thrown by {@code r}

     * are thrown here.

     * <p/>

     * See {@link #asyncExec}.

     *

     * @param	    r

     *		    the {@link NavRunnable} to run

     */

    public void asyncExecAndWait(final NavRunnable r)

	throws NavigationAbortedException, InvalidAddressException,

	MissingParameterException, InvalidParameterException {

	if (isDispatchThread()) {

	    r.run();

	    return;

	}

	final boolean[] done = {false};

	final Throwable[] throwable = {null};

	asyncExec(

	    new Runnable() {

		@Override

		public void run() {

		    try {

			r.run();

		    } catch (Throwable t) {

			throwable[0] = t;

		    }

		    synchronized (done) {

			done[0] = true;

			done.notify();

		    }

		}

	    });

	// Sleep until nav thread is done

	synchronized (done) {

	    while (!done[0]) {

		try {

		    done.wait();

		} catch (InterruptedException ignore) {

		}

	    }

	}

	Throwable t = throwable[0];

	if (t != null) {

	    if (t instanceof NavigationAbortedException)

		throw (NavigationAbortedException)t;

	    if (t instanceof InvalidAddressException)

		throw (InvalidAddressException)t;

	    if (t instanceof MissingParameterException)

		throw (MissingParameterException)t;

	    if (t instanceof InvalidParameterException)

		throw (InvalidParameterException)t;

	    if (t instanceof RuntimeException)

		throw (RuntimeException)t;

	    if (t instanceof Error)

		throw (Error)t;

	    // All Throwables should be accounted for

	    assert false;

	}

    }

    /**

     * Notifies all registered {@link NavigationListener}s that a navigation has

     * begun.

     */

    protected void fireNavigationStarted(NavigationEvent e) {

	listeners.navigationStarted(e);

    }

    /**

     * Notifies all registered {@link NavigationListener}s that a navigation has

     * stopped.

     */

    protected void fireNavigationStopped(NavigationEvent e) {

	listeners.navigationStopped(e);

    }

    /**

     * Returns the current {@link Control}, or {@code null} if the root element

     * of the navigation stack has not yet been set.

     */

    public Control getCurrentControl() {

	synchronized (stack) {

	    return stack.peekLast();

	}

    }

    /**

     * Gets a list of the elements of the current path, with the root element at

     * the beginning of the list.  This method is not thread-safe; it is up to

     * callers to ensure the that navigation is not currently modifying this

     * path.

     */

    @SuppressWarnings({"unchecked"})

    public List<Control> getPath() {

	return (List<Control>)stack.clone();

    }

    /**

     * Gets the current path as a {@code String}.  This method is not

     * thread-safe; it is up to callers to ensure the that navigation is not

     * currently modifying this path.

     */

    public String getPathString() {

	return getPathString(stack);

    }

    /**

     * Navigates to the {@link Control} identified by the given path.

     *

     * @param	    cancel

     *		    {@code true} if the {@code Control}s, if any, that are

     *		    stopped as part of this navigation should be cancelled,

     *		    {@code false} otherwise; this parameter is passed along to

     *		    the {@link Control#stop} method

     *

     * @param	    relativeTo

     *		    a {@link Control} within the navigation stack to which

     *		    {@code path} is relative, or {@code null} if {@code path} is

     *		    absolute

     *

     * @param	    path

     *		    the path (relative to {@code relativeTo}), or unspecified to

     *		    navigate up the stack to {@code relativeTo}; if the root of

     *		    this {@code Navigator} has not yet been set, the first

     *		    element of this path <strong>must</strong> be a {@link

     *		    Control}

     *

     * @return	    the previously current {@link Control}, or {@code null} if

     *		    the root {@link Control} of the navigation stack has not yet

     *		    been set

     *

     * @exception   NavigationAbortedException

     *		    if the navigation is vetoed

     *

     * @exception   InvalidAddressException

     *		    if {@code path} does not refer to a valid address

     *

     * @exception   MissingParameterException

     *		    if some {@link Control} in the process of navigation could

     *		    not be {@link Control#start started} due to a missing

     *		    intialization parameter

     *

     * @exception   InvalidParameterException

     *		    if some {@link Control} in the process of navigation could

     *		    not be {@link Control#start started} due to an invalid

     *		    intialization parameter

     *

     * @exception   IllegalArgumentException

     *		    if {@code relativeTo} is not in the navigation stack

     */

    public Control goTo(boolean cancel, Control relativeTo, Navigable... path)

	throws NavigationAbortedException, InvalidAddressException,

	MissingParameterException, InvalidParameterException {

	assert isDispatchThread();

	synchronized (stack) {

	    // The original Control, before navigation

	    Control orig = getCurrentControl();

	    List<Control> stopped = new ArrayList<Control>();

	    List<Control> started = new ArrayList<Control>();

	    boolean needStopEvent = false;

	    try {

		boolean done = false;

		while (!done) {

		    // Last absolute path

		    LinkedList<Navigable> laPath = new LinkedList<Navigable>();

		    laPath.addAll(stack);

		    // Current absolute path

		    LinkedList<Navigable> caPath = new LinkedList<Navigable>();

		    if (relativeTo != null) {

			caPath.addAll(laPath);

			try {

			    // Remove path elements until relativeTo is at top

			    while (!((HasControl)caPath.getLast()).getControl().

				equals(relativeTo)) {

				caPath.removeLast();

			    }

			} catch (NoSuchElementException e) {

			    throw new IllegalArgumentException(String.format(

				"Control not in navigation path: %s (%s)",

				relativeTo.getClass().getName(),

				relativeTo.getId()));

			}

		    }

		    if (path.length != 0) {

			CollectionUtil.addAll(caPath, path);

			// Remove unnecessary ".." segments

			normalize(caPath);

		    }

		    List<Navigable> relPath = getRelativePath(laPath, caPath);

		    if (!relPath.isEmpty()) {

			// Iterate through relPath, adding/removing elements

			// to/from laPath as appropriate

			for (Navigable nav : relPath) {

			    if (nav.getId().equals(PARENT_ID)) {

				try {

				    laPath.removeLast();

				} catch (NoSuchElementException e) {

				    throw new IllegalArgumentException(

					"\"..\" encountered with empty " +

					"navigation stack");

				}

			    } else {

				Control newControl;

				// If the Navigation stack has no root...

				if (laPath.isEmpty()) {

				    try {

					newControl = (Control)nav;

				    } catch (ClassCastException e) {

					throw new IllegalArgumentException(

					    "root-level Navigable \"" +

					    nav.getName() +

					    "\" must be a Control");

				    }

				} else {

				    String id = nav.getId();

				    Object last = laPath.getLast();

				    // laPath elements are Controls or

				    // PendingControls

				    Control curControl =

					((HasControl)last).getControl();

				    newControl = curControl.getChildControl(id);

				    if (newControl == null) {

					throw new InvalidAddressException(

					    String.format("%s%s%s",

					    getPathString(laPath),

					    PATH_SEPARATOR, id));

				    }

				}

				PendingControl pair = new PendingControl(

				    newControl, nav.getParameters());

				laPath.add(pair);

			    }

			}

		    }

		    @SuppressWarnings({"unchecked"})

		    List<PendingControl> rPath = (List<PendingControl>)(List)

			getRelativePath(stack, laPath);

		    if (!rPath.isEmpty()) {

			List<PendingControl> roRPath =

			    Collections.unmodifiableList(rPath);

			NavigationEvent event = new NavigationEvent(this,

			    roRPath);

			fireNavigationStarted(event);

			needStopEvent = true;

			for (PendingControl pend : rPath) {

			    Control curControl = getCurrentControl();

			    if (pend.getId().equals(PARENT_ID)) {

				curControl.stop(cancel);

				stopped.add(curControl);

				stack.removeLast();

				descendantStopped(curControl);

			    } else {

				Control newControl = pend.getControl();

				newControl.start(this, pend.getParameters());

				started.add(newControl);

				stack.add(newControl);

				descendantStarted();

			    }

			    if (System.getProperty("vpanels.debug.navigator") !=

				null) {

				System.out.printf("%s\n", getPathString());

			    }

			}

		    }

		    // Navigation is complete.	However, if the current

		    // Control's getForwardingPath returns a non-null value,

		    // invoke another round of navigation.

		    done = true;

		    Control curControl = getCurrentControl();

		    if (curControl != null) {

			Navigable[] forward = curControl.getForwardingPath();

			if (forward != null && forward.length != 0) {

			    // Is this path absolute?

			    if (forward[0] == null) {

				relativeTo = null;

				path = new Navigable[forward.length - 1];

				System.arraycopy(forward, 1, path, 0,

				    path.length);

			    } else {

				relativeTo = curControl;

				path = forward;

			    }

			    done = false;

			}

		    }

		}

	    } finally {

		if (needStopEvent) {

		    NavigationEvent event = new NavigationEvent(this,

			Collections.unmodifiableList(stopped),

			Collections.unmodifiableList(started));

		    fireNavigationStopped(event);

		}

	    }

	    return orig;

	}

    }

    /**

     * Asynchronously navigates to the {@link Control} identified by the

     * given path.  A wrapper around {@link #goTo(boolean,Control,Navigable...)}

     * that is run asynchronously using {@link #asyncExec}.

     */

    public void goToAsync(final boolean cancel, final Control relativeTo,

	final Navigable... path) {

	asyncExec(

	    new Runnable() {

		@Override

		public void run() {

		    try {

			goTo(cancel, relativeTo, path);

		    } catch (NavigationException ignore) {

		    }

		}

	    });

    }

    /**

     * Asynchronously navigates to the {@link Control} identified by the given

     * path, returning only when navigation is complete.  A wrapper around

     * {@link #goTo(boolean,Control,Navigable...)} that is run asynchronously

     * using {@link #asyncExecAndWait}.

     */

    public void goToAsyncAndWait(final boolean cancel, final Control relativeTo,

	final Navigable... path) throws NavigationAbortedException,

	InvalidAddressException, MissingParameterException,

	InvalidParameterException {

	asyncExecAndWait(

	    new NavRunnable() {

		@Override

		public void run()

		    throws NavigationAbortedException, InvalidAddressException,

		    MissingParameterException, InvalidParameterException {

		    goTo(cancel, relativeTo, path);

		}

	    });

    }

    /**

     * Determines whether the current thread is the navigation dispatch thread.

     * The navigation dispatch thread may change over time, but only one is

     * alive at a time.

     */

    public boolean isDispatchThread() {

	return Thread.currentThread() == dispatchThread;

    }

    /**