/*

 * 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 (c) 2010, 2012, Oracle and/or its affiliates. All rights reserved.

 */

package com.oracle.solaris.vp.client.common;

import java.awt.*;

import java.util.*;

import java.util.List;

import javax.management.*;

import javax.management.remote.JMXConnectionNotification;

import javax.swing.tree.*;

import javax.swing.WindowConstants;

import com.oracle.solaris.vp.panel.common.*;

import com.oracle.solaris.vp.util.misc.EnumerationIterator;

import com.oracle.solaris.vp.util.swing.*;

import com.oracle.solaris.vp.util.swing.tree.TypedTreeNode;

/**

 * The {@code ConnectionManager} class maintains a dependency tree of {@link

 * ConnectionInfo}s and {@link ConnectionListener}s.

 * <p/>

 * Dependencies between connections could be hard (connection {@code b} actively

 * uses connection {@code a} to communicate) or soft ({@code a} was created in

 * the process of creating {@code b}, and {@code a} should be maintained while

 * {@code b} is active in case the user wants to return to {@code a} at some

 * point without having to re-authenticate).

 * <p/>

 * Each connection in the tree is managed until it has no dependants (other

 * connections or listeners), at which point it is removed from the dependency

 * tree.  If there are no other references to it outside of this class, it will

 * be garbage collected (and thus closed).

 */

public class ConnectionManager {

    //

    // Inner classes

    //

    /**

     * Graphically display the dependency tree for debugging.

     */

    private class Visualizer {

	//

	// Instance data

	//

	private DefaultTreeModel model = new DefaultTreeModel(root);

	private ExtTree tree = new ExtTree(model);

	//

	// Constructors

	//

	public Visualizer() {

	    ExtFrame frame = new ExtFrame();

	    frame.setAutoResizeEnabled(true);

	    Container cont = frame.getContentPane();

	    cont.setLayout(new BorderLayout());

	    cont.add(tree, BorderLayout.CENTER);

	    frame.setLocationByPlatform(true);

	    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

	    frame.pack();

	    frame.setVisible(true);

	}

	//

	// Visualizer methods

	//

	public void update() {

	    EventQueue.invokeLater(

		new Runnable() {

		    @Override

		    public void run() {

			model.nodeStructureChanged(root);

			tree.setExpandedRecursive(true);

		    }

		});

	}

    }

    private class DependencyTreeNode<T> extends TypedTreeNode<T> {

	//

	// Constructors

	//

	public DependencyTreeNode(T userObject) {

	    super(userObject);

	}

	//

	// DefaultMutableTreeNode methods

	//

	@Override

	public void add(MutableTreeNode child) {

	    super.add(child);

	    DependencyTreeNode node = (DependencyTreeNode)child;

	    nodeMap.put(node.getUserObject(), node);

	    if (visualizer != null) {

		visualizer.update();

	    }

	}

	@Override

	public void remove(MutableTreeNode child) {

	    super.remove(child);

	    DependencyTreeNode node = (DependencyTreeNode)child;

	    nodeMap.remove(node.getUserObject());

	    if (visualizer != null) {

		visualizer.update();

	    }

	}

	//

	// DependencyTreeNode methods

	//

	@SuppressWarnings({"unchecked"})

	public Iterable<DependencyTreeNode> getChildren() {

	    return new EnumerationIterator<DependencyTreeNode>(children());

	}

    }

    private class ConnectionTreeNode

	extends DependencyTreeNode<ConnectionInfo> {

	//

	// Instance data

	//

	private boolean healthy = true;

	//

	// Constructors

	//

	public ConnectionTreeNode(ConnectionInfo info) {

	    super(info);

	}

	//

	// Object methods

	//

	@Override

	public String toString() {

	    return String.format("%s: %s (%s)", getUserObject().hashCode(),

		super.toString(), isHealthy() ? "healthy" : "unhealthy");

	}

	//

	// ConnectionTreeNode methods

	//

	public boolean isHealthy() {

	    return healthy;

	}

	public void setHealthy(boolean healthy) {

	    this.healthy = healthy;

	    if (visualizer != null) {

		visualizer.update();

	    }

	}

    }

    private class ListenerTreeNode

	extends DependencyTreeNode<ConnectionListener> {

	//

	// Constructors

	//

	public ListenerTreeNode(ConnectionListener listener) {

	    super(listener);

	}

    }

    //

    // Static data

    //

    private static NotificationFilter nFilter =

	new NotificationFilter() {

	    @Override

	    public boolean isNotificationEnabled(Notification notification) {

		return notification.getType().equals(

		    JMXConnectionNotification.FAILED);

	    }

	};

    //

    // Instance data

    //

    private DependencyTreeNode<?> root = new DependencyTreeNode<Object>(null);

    // Set to null unless debugging

    private Visualizer visualizer = null;

    private Map<Object, DependencyTreeNode> nodeMap =

	new HashMap<Object, DependencyTreeNode>();

    private NotificationListener nListener =

	new NotificationListener() {

	    @Override

	    public void handleNotification(Notification notification,

		Object handback) {

		if (nFilter.isNotificationEnabled(notification)) {

		    ConnectionTreeNode node = (ConnectionTreeNode)handback;

		    fireConnectionFailed(node);

		}

	    }

	};

    private ConnectionListListeners listeners =

        new ConnectionListListeners();

    //

    // ConnectionManager methods

    //

    /**

     * Adds a dependency chain of {@link ConnectionInfo}s and a {@link

     * ConnectionListener} to the dependency tree.  The first element of {@code

     * depChain} is a dependency of {@code listener}.  Each additional element

     * is a dependency of the previous element.

     * <p/>

     * {@code listener} will be notified when the first {@code ConnectionInfo}

     * in the chain {@link ConnectionListener#connectionFailed fails} or {@link

     * ConnectionListener#connectionChanged is replaced}.

     * <p/>

     * {@code listener} and {@code depChain} are merged into the tree if any

     * element thereof already exists in the tree.

     *

     * @param	    listener

     *		    a {@link ConnectionListener} utilizing the first

     *		    {@code ConnectionInfo} in {@code depChain}

     *

     * @param	    depChain

     *		    the {@link ConnectionInfo} dependency chain

     *

     * @throws	    IllegalStateException

     *		    if the given dependency chain conflicts with the existing

     *		    dependency tree

     */

    public synchronized void add(ConnectionListener listener,

	List<ConnectionInfo> depChain) {

	if (depChain.isEmpty()) {

	    return;

	}

	DependencyTreeNode parent = root;

	for (int last = depChain.size() - 1, i = last; i >= 0; i--) {

	    ConnectionInfo info = depChain.get(i);

	    DependencyTreeNode node = getNode(info);

	    if (node != null) {

                DependencyTreeNode oldParent =

		    (DependencyTreeNode)node.getParent();

		if (oldParent != parent) {

		    if (parent == root) {

			parent = oldParent;

		    } else if (oldParent != root) {

                        // If this connection already depends on a connection

                        // other than the next one in depChain...

			throw new IllegalStateException(String.format(

			    "\"%s\" should depend on \"%s\" but already " +

			    "depends on \"%s\"", info,

			    ((ConnectionTreeNode)parent).getUserObject(),

			    ((ConnectionTreeNode)oldParent).getUserObject()));

		    } else {

			if (parent.isNodeAncestor(node)) {

			    throw new IllegalStateException(String.format(

				"\"%s\" should depend on \"%s\" but " +

				"existing dependencies are reversed", info,

				((ConnectionTreeNode)parent).

				getUserObject()));

			}

			parent.add(node);

		    }

		}

		parent = node;

		continue;

	    }

	    node = new ConnectionTreeNode(info);

	    info.getConnector().addConnectionNotificationListener(

		nListener, nFilter, node);

	    parent.add(node);

	    fireAddEvent(info);

	    parent = node;

	    // Does this new connection replace one or more failed connections?

	    for (ConnectionTreeNode failed : getFailed()) {

		if (failed.getUserObject().matches(info)) {

		    ConnectionEvent event = null;

		    // Adopt failed node's dependants and notify them of change

		    for (TreeNode child : failed.getChildren()) {

			node.add((MutableTreeNode)child);

			if (child instanceof ListenerTreeNode) {

			    if (event == null) {

				event = new ConnectionEvent(

				    this, info, failed.getUserObject());

			    }

			    ((ListenerTreeNode)child).getUserObject().

				connectionChanged(event);

			}

		    }

		    remove(failed);

		}

	    }

	}

        // Listener could be at the end of multiple dependency chains.  Ensure

        // that it is listening to the first connection in depChain.

	ListenerTreeNode node = getChild(parent, listener);

	if (node == null) {

	    node = new ListenerTreeNode(listener);

	    parent.add(node);

	}

	fireSelectedEvent(depChain.get(0));

    }

    /**

     * Adds a {@code ConnectionListListener} to notification.

     */

    public synchronized void addConnectionListListener(

	ConnectionListListener listener) {

	listeners.add(listener);

    }

    /**

     * Gets a dependency chain of {@link ConnectionInfo}s, with the first

     * element healthy and matching the given connection parameters, or {@code

     * null} if no healthy matching {@code ConnectionInfo} exists.

     */

    public synchronized List<ConnectionInfo> getDepChain(String host,

        String user, String role, String zone, String zoneUser, String zoneRole)

    {

	for (DependencyTreeNode node : nodeMap.values()) {

	    if (node instanceof ConnectionTreeNode) {

		ConnectionTreeNode cNode = (ConnectionTreeNode)node;

		ConnectionInfo info = cNode.getUserObject();

                if (cNode.isHealthy() && info.matches(host, user, role, zone,

		    zoneUser, zoneRole)) {

		    List<ConnectionInfo> depChain =

			new LinkedList<ConnectionInfo>();

		    for (TreeNode n = node; n != root; n = n.getParent()) {

			depChain.add(((ConnectionTreeNode)n).getUserObject());

		    }

		    return depChain;

		}

	    }

	}

	return null;

    }

    /**

     * Removes {@code listener} as a listener to/dependency of {@code info}.

     * Any connection leaf nodes in the resulting dependency tree will be

     * removed from the tree.

     *

     * @param	    listener

     *		    a {@link ConnectionListener} that depends on {@code info}

     *

     * @param	    info

     *		    the {@link ConnectionInfo} in the dependency tree

     *

     * @throws	    IllegalArgumentException

     *		    if {@code listener} does not depend on {@code info}

     */

    public synchronized void remove(ConnectionListener listener,

	ConnectionInfo info) {

	DependencyTreeNode parent = getNode(info);

	if (parent == null) {

	    throw new IllegalArgumentException(String.format(

		"listener does not depend on \"%s\"", info));

	}

	ListenerTreeNode node = getChild(parent, listener);

	if (node == null) {

	    throw new IllegalArgumentException(String.format(

		"listener does not depend on \"%s\"", info));

	}

	remove(node);

    }

    /**

     * Removes a {@code ConnectionListListener} from notification.

     */

    public synchronized void removeConnectionListListener(

	ConnectionListListener listener) {

	listeners.remove(listener);

    }

    //

    // Private methods

    //

    private synchronized void fireAddEvent(ConnectionInfo info) {

        listeners.connectionAdded(new ConnectionEvent(this, info));

    }

    private synchronized void fireConnectionFailed(ConnectionTreeNode node) {

	node.setHealthy(false);

	ConnectionEvent event = null;

	// Forward to any ConnectionListener dependants

	for (TreeNode child : node.getChildren()) {

	    if (child instanceof ListenerTreeNode) {

		if (event == null) {

		    event = new ConnectionEvent(this, node.getUserObject());

		}

		ConnectionListener listener =

		    ((ListenerTreeNode)child).getUserObject();

		listener.connectionFailed(event);

	    }

	}

    }

    private synchronized void fireRemoveEvent(ConnectionInfo info) {

	listeners.connectionRemoved(new ConnectionEvent(this, info));

    }

    private synchronized void fireSelectedEvent(ConnectionInfo info) {

	listeners.connectionSelected(new ConnectionEvent(this, info));

    }

    /**

     * Returns the dependent child {@code ListenerTreeNode} of {@code node} for

     * the given {@code listener}, {@code null} if none is found.

     */

    private ListenerTreeNode getChild(DependencyTreeNode<?> parent,

	ConnectionListener listener) {

	for (DependencyTreeNode child : parent.getChildren()) {

	    if (child instanceof ListenerTreeNode &&

		child.getUserObject() == listener) {

		return (ListenerTreeNode)child;

	    }

	}

	return null;

    }

    private synchronized List<ConnectionTreeNode> getFailed() {

	List<ConnectionTreeNode> list = new LinkedList<ConnectionTreeNode>();

	for (DependencyTreeNode node : nodeMap.values()) {

	    if (node instanceof ConnectionTreeNode) {

		ConnectionTreeNode cNode = (ConnectionTreeNode)node;

		if (!cNode.isHealthy()) {

		    list.add(cNode);

		}

	    }

	}

	return list;

    }

    private synchronized DependencyTreeNode getNode(Object userObj) {

	for (Map.Entry<Object, DependencyTreeNode> entry : nodeMap.entrySet()) {

	    Object key = entry.getKey();

	    if (key == userObj) {

		return entry.getValue();

	    }

	}

	return null;

    }

    private synchronized void remove(DependencyTreeNode<?> node) {

	for (DependencyTreeNode child : node.getChildren()) {

	    remove(child);

	}

	if (node instanceof ConnectionTreeNode) {

	    ConnectionInfo info = ((ConnectionTreeNode)node).getUserObject();

	    try {

		info.getConnector().removeConnectionNotificationListener(

		    nListener);

	    } catch (ListenerNotFoundException ignore) {

	    }

	}

	DependencyTreeNode<?> parent = (DependencyTreeNode)node.getParent();

	parent.remove(node);

	if (node instanceof ConnectionTreeNode) {

	    ConnectionInfo info = ((ConnectionTreeNode)node).getUserObject();

	    fireRemoveEvent(info);