/*

 * 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.io.*;

import java.util.*;

import java.util.logging.*;

import javax.swing.event.*;

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

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

import com.oracle.solaris.vp.util.swing.event.ChangeListeners;

public class LoginHistoryManager implements LoginHistory {

    //

    // Instance data

    //

    // Used to format logins as host:user:role

    private static final String LOGIN_DELIMITER = ":";

    // Default login history size.

    private static final int LOGIN_SIZE = 256;

    // Login history size.

    private int loginSize;

    // File used to persist login history.

    private File loginFile;

    // List used to maintain login history.

    private LinkedList<LoginInfo> logins = new LinkedList<LoginInfo>();

    // ConnectionManager used for logins.

    private ConnectionManager connManager = null;

    // login history listeners.

    private ChangeListeners listeners = new ChangeListeners();

    // ConnectionManager listener.

    private ConnectionListListener connListener =

	new ConnectionListListener() {

	    @Override

	    public void connectionRemoved(ConnectionEvent event) {

		// Nothing to do here.

	    }

	    @Override

	    public void connectionAdded(ConnectionEvent event) {

		connectionChanged(event);

	    }

	    @Override

	    public void connectionSelected(ConnectionEvent event) {

		connectionChanged(event);

	    }

	    private void connectionChanged(ConnectionEvent event) {

		LoginInfo info = (LoginInfo) event.getConnectionInfo();

		addLogin(info);

		writeLogins();

		fireStateChanged();

	    }

	};

    //

    // Constructors

    //

    /**

     * Create an instance of this class.

     *

     * @param manager The {@code ConnectionManager} associated with logins.

     * @param file The {@code File} used to persist login history.

     */

    public LoginHistoryManager(ConnectionManager manager, File file) {

	this(manager, file, LOGIN_SIZE);

    }

    /**

     * Create an instance of this class.

     *

     * @param manager The {@code ConnectionManager} associated with logins.

     * @param file The {@code File} used to persist login history.

     * @param size The size of the persisted login history.

     */

    public LoginHistoryManager(ConnectionManager manager, File file, int size) {

	loginFile = file;

	connManager = manager;

	connManager.addConnectionListListener(connListener);

	setSize(size);

	readLogins();

    }

    //

    // LoginHistory methods

    //

    @Override

    public void clearLogins() {

	logins.clear();

	loginFile.delete();

	fireStateChanged();

    }

    @Override

    public List<LoginInfo> getLogins() {

	return new ArrayList<LoginInfo>(logins);

    }

    @Override

    public List<LoginInfo> getLogins(int size) {

	List<LoginInfo> list = getLogins();

	try {

	    return list.subList(0, size);

	} catch (IndexOutOfBoundsException e) {

	    return list;

	}

    }

    @Override

    public void addChangeListener(ChangeListener listener) {

	listeners.add(listener);

    }

    @Override

    public void removeChangeListener(ChangeListener listener) {

	listeners.remove(listener);

    }

    //

    // LoginHistoryManager methods

    //

    /**

     * Get the size of persisted login history.

     */

    public int getSize() {

	return loginSize;

    }

    /**

     * Set the size of persisted login history. If size is negative, the default

     * size shall be used.

     *

     * @param size The login history size.

     */

    public void setSize(int size) {

	loginSize = (size < 0) ? LOGIN_SIZE : size;

	if (logins.size() > loginSize) {

	    for (int i = logins.size() - 1; i >= loginSize; i--) {

		logins.remove(i);

	    }

	    writeLogins();

	    fireStateChanged();

	}

    }

    //

    // Private methods

    //

    // Add logins in FIFO order.

    private void addLogin(LoginInfo info) {

	removeLogin(info);

	logins.addFirst(info);

	if (logins.size() > loginSize) {

	    logins.removeLast();

	}

    }

    // Fire property change event.

    private void fireStateChanged() {

	listeners.stateChanged(new ChangeEvent(this));

    }

    private static String nullIfEmpty(String s) {

	return s.length() > 0 ? s : null;

    }

    // Push logins in LIFO order.

    private void pushLogin(LoginInfo info) {

	removeLogin(info);

	logins.addLast(info);

	if (logins.size() > loginSize) {

	    logins.removeFirst();

	}

    }

    // Remove existing login.

    private void removeLogin(LoginInfo info) {

	for (int i = 0; i < logins.size(); i++) {

	    LoginInfo login = logins.get(i);

	    if (info.matches(login)) {

		logins.remove(i);

		return;

	    }

	}

    }

    // Read persistent login history.

    private void readLogins() {

	if (!loginFile.exists()) {

	    return;

	}

	if (!loginFile.canRead()) {

	    String message = "cannot read login history: " +

		loginFile.getAbsolutePath();

	    Logger.getLogger(getClass().getName()).log(

		Level.WARNING, message);

	    return;

	}

	try {

	    BufferedReader reader = new BufferedReader(

		new FileReader(loginFile));

	    int i = 0;

	    String line;

	    while ((line = reader.readLine()) != null && i++ < loginSize) {

		String[] fields = line.split(LOGIN_DELIMITER);

		String host = null;

		String user = null;

		String role = null;

		String zone = null;

		String zoneUser = null;

		String zoneRole = null;

		try {

		    host = nullIfEmpty(fields[0]);

		    user = nullIfEmpty(fields[1]);

		    role = nullIfEmpty(fields[2]);

		    zone = nullIfEmpty(fields[3]);

		    zoneUser = nullIfEmpty(fields[4]);

		    zoneRole = nullIfEmpty(fields[5]);

		} catch (ArrayIndexOutOfBoundsException stop) {

		}

		if (host != null && user != null) {

		    ConnectionInfo info = new ConnectionInfo(

			host, user, role, zone, zoneUser, zoneRole, null);

		    pushLogin(info);

		}

	    }

	    reader.close();

	} catch (IOException e) {

	    String message = "error reading login history";

	    Logger.getLogger(getClass().getName()).log(

		Level.WARNING, message, e);

	}

    }

    // Write persistent login history.

    private void writeLogins() {

	File loginDir = loginFile.getParentFile();

	// Ensure directory exists.

	if (!loginDir.exists() && !loginDir.mkdirs()) {

	    String message = "Cannot create login history directory: " +

		loginDir.getAbsolutePath();

	    Logger.getLogger(getClass().getName()).log(

		Level.WARNING, message);

	    return;

	}

	try {

	    File tmpFile = File.createTempFile(loginFile.getName(), ".tmp",

		loginDir);

	    PrintWriter writer = new PrintWriter(new FileWriter(tmpFile));

	    for (LoginInfo login : logins) {

                writer.println(TextUtil.join(LOGIN_DELIMITER, login.getHost(),

		    login.getUser(), login.getRole(), login.getZone(),

		    login.getZoneUser(), login.getZoneRole()));

	    }

	    tmpFile.renameTo(loginFile);

	    writer.close();

	} catch (IOException e) {

	    String message = "Cannot persist login history";

	    Logger.getLogger(getClass().getName()).log(

		Level.WARNING, message, e);

	}

    }

}