/*
 * Copyright (C) 2005-2006 Alfresco, Inc.
 *
 * Licensed under the Mozilla Public License version 1.1 
 * with a permitted attribution clause. You may obtain a
 * copy of the License at
 *
 *   http://www.alfresco.org/legal/license.txt
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the
 * License.
 */
package org.alfresco.filesys.smb.server;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.util.Enumeration;
import java.util.UUID;
import java.util.Vector;

import org.alfresco.filesys.netbios.NetworkSettings;
import org.alfresco.filesys.server.ServerListener;
import org.alfresco.filesys.server.SrvSessionList;
import org.alfresco.filesys.server.config.ServerConfiguration;
import org.alfresco.filesys.server.core.InvalidDeviceInterfaceException;
import org.alfresco.filesys.server.core.ShareType;
import org.alfresco.filesys.server.core.SharedDevice;
import org.alfresco.filesys.server.filesys.DiskInterface;
import org.alfresco.filesys.server.filesys.NetworkFileServer;
import org.alfresco.filesys.smb.SMBException;
import org.alfresco.filesys.smb.ServerType;
import org.alfresco.filesys.smb.mailslot.HostAnnouncer;
import org.alfresco.filesys.smb.server.win32.Win32NetBIOSLanaMonitor;
import org.alfresco.filesys.smb.server.win32.Win32NetBIOSSessionSocketHandler;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * SMB Server Class
 * 
 * <p>Creates an SMB server with the specified host name.
 * 
 * <p>The server can optionally announce itself so that it will appear under the Network Neighborhood,
 * by enabling the host announcer in the server configuration or using the enableAnnouncer() method.
 */
public class SMBServer extends NetworkFileServer implements Runnable
{

    // Debug logging

    private static final Log logger = LogFactory.getLog("org.alfresco.smb.protocol");

    // Server version

    private static final String ServerVersion = "3.5.1";

    // Server thread

    private Thread m_srvThread;

    // Session socket handlers (NetBIOS over TCP/IP, native SMB and/or Win32 NetBIOS)

    private Vector<SessionSocketHandler> m_sessionHandlers;

    // Host announcers, server will appear under Network Neighborhood

    private Vector<HostAnnouncer> m_hostAnnouncers;

    // Active session list

    private SrvSessionList m_sessions;

    // Server type flags, used when announcing the host

    private int m_srvType = ServerType.WorkStation + ServerType.Server + ServerType.NTServer;

    // Server GUID
    
    private UUID m_serverGUID;
    
    /**
     * Create an SMB server using the specified configuration.
     *
     * @param serviceRegistry repository connection
     * @param cfg ServerConfiguration
     */
    public SMBServer(ServerConfiguration cfg) throws IOException
    {
        super("SMB", cfg);

        // Call the common constructor
        CommonConstructor();
    }

    /**
     * Add a shared device to the server.
     * 
     * @param shr Shared device to be added to the server.
     * @return True if the share was added successfully, else false.
     */
    public final synchronized boolean addShare(SharedDevice shr)
    {

        // For disk devices check if the shared device is read-only, this should also check if the
        // shared device path actully exists.

        if (shr.getType() == ShareType.DISK)
        {

            // Check if the disk device is read-only

            checkReadOnly(shr);
        }

        // Add the share to the shared device list

        boolean sts = getConfiguration().getShares().addShare(shr);

        // Debug

        if (logger.isInfoEnabled())
            logger.info("Add Share " + shr.toString() + " : " + sts);

        // Return the add share status

        return sts;
    }

    /**
     * Add a session handler
     * 
     * @param sessHandler SessionSocketHandler
     */
    public final void addSessionHandler(SessionSocketHandler handler)
    {

        // Check if the session handler list has been allocated

        if (m_sessionHandlers == null)
            m_sessionHandlers = new Vector<SessionSocketHandler>();

        // Add the session handler

        m_sessionHandlers.addElement(handler);
    }

    /**
     * Add a host announcer
     * 
     * @param announcer HostAnnouncer
     */
    public final void addHostAnnouncer(HostAnnouncer announcer)
    {

        // Check if the host announcer list has been allocated

        if (m_hostAnnouncers == null)
            m_hostAnnouncers = new Vector<HostAnnouncer>();

        // Add the host announcer

        m_hostAnnouncers.addElement(announcer);
    }

    /**
     * Add a new session to the server
     * 
     * @param sess SMBSrvSession
     */
    public final void addSession(SMBSrvSession sess)
    {

        // Add the session to the session list

        m_sessions.addSession(sess);

        // Propagate the debug settings to the new session

        sess.setDebug(getConfiguration().getSessionDebugFlags());
    }

    /**
     * Check if the disk share is read-only.
     * 
     * @param shr SharedDevice
     */
    protected final void checkReadOnly(SharedDevice shr)
    {

        // For disk devices check if the shared device is read-only, this should also check if the
        // shared device
        // path actully exists.

        if (shr.getType() == ShareType.DISK)
        {

            // Check if the disk device is read-only

            try
            {

                // Get the device interface for the shared device

                DiskInterface disk = (DiskInterface) shr.getInterface();
                if (disk.isReadOnly(null, shr.getContext()))
                {

                    // The disk is read-only, mark the share as read-only

                    int attr = shr.getAttributes();
                    if ((attr & SharedDevice.ReadOnly) == 0)
                        attr += SharedDevice.ReadOnly;
                    shr.setAttributes(attr);

                    // Debug

                    if (logger.isInfoEnabled())
                        logger.info("[SMB] Add Share " + shr.toString() + " : isReadOnly");
                }
            }
            catch (InvalidDeviceInterfaceException ex)
            {

                // Shared device interface error

                if (logger.isInfoEnabled())
                    logger.info("[SMB] Add Share " + shr.toString() + " : " + ex.toString());
                return;
            }
            catch (FileNotFoundException ex)
            {

                // Shared disk device local path does not exist

                if (logger.isInfoEnabled())
                    logger.info("[SMB] Add Share " + shr.toString() + " : " + ex.toString());
                return;
            }
            catch (IOException ex)
            {

                // Shared disk device access error

                if (logger.isInfoEnabled())
                    logger.info("[SMB] Add Share " + shr.toString() + " : " + ex.toString());
                return;
            }
        }
    }

    /**
     * Common constructor code.
     */
    private void CommonConstructor() throws IOException
    {

        // Set the server version

        setVersion(ServerVersion);

        // Create the session socket handler list

        m_sessionHandlers = new Vector<SessionSocketHandler>();

        // Create the active session list

        m_sessions = new SrvSessionList();

        // Set the global domain name

        NetworkSettings.setDomain(getConfiguration().getDomainName());
        NetworkSettings.setBroadcastMask(getConfiguration().getBroadcastMask());
    }

    /**
     * Close the host announcer, if enabled
     */
    protected void closeHostAnnouncers()
    {

        // Check if there are active host announcers

        if (m_hostAnnouncers != null)
        {

            // Shutdown the host announcers

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

                // Get the current host announcer from the active list

                HostAnnouncer announcer = (HostAnnouncer) m_hostAnnouncers.elementAt(i);

                // Shutdown the host announcer

                announcer.shutdownAnnouncer();
            }
        }
    }

    /**
     * Close the session handlers
     */
    protected void closeSessionHandlers()
    {

        // Close the session handlers

        for (SessionSocketHandler handler : m_sessionHandlers)
        {

            // Request the handler to shutdown

            handler.shutdownRequest();
        }

        // Clear the session handler list

        m_sessionHandlers.removeAllElements();
    }

    /**
     * Delete the specified shared device from the server.
     * 
     * @param name String Name of the shared resource to remove from the server.
     * @return SharedDevice that has been removed from the server, else null.
     */
    public final synchronized SharedDevice deleteShare(String name)
    {
        return getConfiguration().getShares().deleteShare(name);
    }

    /**
     * Delete temporary shares created by the share mapper for the specified session
     * 
     * @param sess SMBSrvSession
     */
    public final void deleteTemporaryShares(SMBSrvSession sess)
    {

        // Delete temporary shares via the share mapper

        getConfiguration().getShareMapper().deleteShares(sess);
    }

    /**
     * Return an enumeration to allow the shared devices to be listed.
     * 
     * @return java.util.Enumeration
     */
    public final Enumeration enumerateShares()
    {
        return getConfiguration().getShares().enumerateShares();
    }

    /**
     * Return the server comment.
     * 
     * @return java.lang.String
     */
    public final String getComment()
    {
        return getConfiguration().getComment();
    }

    /**
     * Return the server type flags.
     * 
     * @return int
     */
    public final int getServerType()
    {
        return m_srvType;
    }

    /**
     * Return the per session debug flag settings.
     */
    public final int getSessionDebug()
    {
        return getConfiguration().getSessionDebugFlags();
    }

    /**
     * Return the active session list
     * 
     * @return SrvSessionList
     */
    public final SrvSessionList getSessions()
    {
        return m_sessions;
    }

    /**
     * Start the SMB server.
     */
    public void run()
    {

        // Indicate that the server is active

        setActive(true);

        // Check if we are running under Windows

        boolean isWindows = isWindowsNTOnwards();

        // Generate a GUID for the server based on the server name
        
        m_serverGUID = UUID.nameUUIDFromBytes( getServerName().getBytes());
        
        // Debug

        if (logger.isInfoEnabled())
        {

            // Dump the server name and GUID

            logger.info("SMB Server " + getServerName() + " starting");
            logger.info("GUID " + m_serverGUID);

            // Output the authenticator details

            if (getAuthenticator() != null)
                logger.info("Using authenticator " + getAuthenticator().getClass().getName());

            // Display the timezone offset/name

            if (getConfiguration().getTimeZone() != null)
                logger.info("Server timezone " + getConfiguration().getTimeZone() + ", offset from UTC = "
                        + getConfiguration().getTimeZoneOffset() / 60 + "hrs");
            else
                logger.info("Server timezone offset = " + getConfiguration().getTimeZoneOffset() / 60 + "hrs");

            // Dump the share list

            logger.info("Shares:");
            Enumeration<SharedDevice> enm = getFullShareList(getServerName(), null).enumerateShares();

            while (enm.hasMoreElements())
            {
                SharedDevice share = enm.nextElement();
                logger.info(" " + share.toString() + " " + share.getContext().toString());
            }
        }

        // Create a server socket to listen for incoming session requests

        try
        {

            // Add the IPC$ named pipe shared device

            AdminSharedDevice admShare = new AdminSharedDevice();
            addShare(admShare);

            // Clear the server shutdown flag

            setShutdown(false);

            // Get the list of IP addresses the server is bound to

            getServerIPAddresses();

            // Check if the socket connection debug flag is enabled

            boolean sockDbg = false;

            if ((getSessionDebug() & SMBSrvSession.DBG_SOCKET) != 0)
                sockDbg = true;

            // Create the NetBIOS session socket handler, if enabled

            if (getConfiguration().hasNetBIOSSMB())
            {

                // Create the TCP/IP NetBIOS SMB/CIFS session handler(s), and host announcer(s) if
                // enabled

                NetBIOSSessionSocketHandler.createSessionHandlers(this, sockDbg);
            }

            // Create the TCP/IP SMB session socket handler, if enabled

            if (getConfiguration().hasTcpipSMB())
            {

                // Create the TCP/IP native SMB session handler(s)

                TcpipSMBSessionSocketHandler.createSessionHandlers(this, sockDbg);
            }

            // Create the Win32 NetBIOS session handler, if enabled

            if (getConfiguration().hasWin32NetBIOS())
            {

                // Only enable if running under Windows

                if (isWindows == true)
                {

                    // Create the Win32 NetBIOS SMB handler(s), and host announcer(s) if enabled

                    Win32NetBIOSSessionSocketHandler.createSessionHandlers(this, sockDbg);
                }
            }

            // Check if there are any session handlers installed, if not then close the server

            if (m_sessionHandlers.size() > 0 || getConfiguration().hasWin32NetBIOS())
            {

                // Wait for incoming connection requests

                while (hasShutdown() == false)
                {

                    // Sleep for a while

                    try
                    {
                        Thread.sleep(1000L);
                    }
                    catch (InterruptedException ex)
                    {
                    }
                }
            }
            else if (logger.isInfoEnabled())
            {

                // DEBUG

                logger.info("No valid session handlers, server closing");
            }
        }
        catch (SMBException ex)
        {

            // Output the exception

            logger.error("SMB server error", ex);

            // Store the error, fire a server error event

            setException(ex);
            fireServerEvent(ServerListener.ServerError);
        }
        catch (Exception ex)
        {

            // Do not report an error if the server has shutdown, closing the server socket
            // causes an exception to be thrown.

            if (hasShutdown() == false)
            {
                logger.error("Server error : ", ex);

                // Store the error, fire a server error event

                setException(ex);
                fireServerEvent(ServerListener.ServerError);
            }
        }

        // Debug

        if (logger.isInfoEnabled())
            logger.info("SMB Server shutting down ...");

        // Close the host announcer and session handlers

        closeHostAnnouncers();
        closeSessionHandlers();

        // Shutdown the Win32 NetBIOS LANA monitor, if enabled

        if (isWindows && Win32NetBIOSLanaMonitor.getLanaMonitor() != null)
            Win32NetBIOSLanaMonitor.getLanaMonitor().shutdownRequest();

        // Indicate that the server is not active

        setActive(false);
        fireServerEvent(ServerListener.ServerShutdown);
    }

    /**
     * Notify the server that a session has been closed.
     * 
     * @param sess SMBSrvSession
     */
    protected final void sessionClosed(SMBSrvSession sess)
    {

        // Remove the session from the active session list

        m_sessions.removeSession(sess);

        // Notify session listeners that a session has been closed

        fireSessionClosedEvent(sess);
    }

    /**
     * Notify the server that a user has logged on.
     * 
     * @param sess SMBSrvSession
     */
    protected final void sessionLoggedOn(SMBSrvSession sess)
    {

        // Notify session listeners that a user has logged on.

        fireSessionLoggedOnEvent(sess);
    }

    /**
     * Notify the server that a session has been closed.
     * 
     * @param sess SMBSrvSession
     */
    protected final void sessionOpened(SMBSrvSession sess)
    {

        // Notify session listeners that a session has been closed

        fireSessionOpenEvent(sess);
    }

    /**
     * Shutdown the SMB server
     * 
     * @param immediate boolean
     */
    public final void shutdownServer(boolean immediate)
    {

        // Indicate that the server is closing

        setShutdown(true);

        try
        {

            // Close the session handlers

            closeSessionHandlers();
        }
        catch (Exception ex)
        {
        }

        // Close the active sessions

        Enumeration<Integer> enm = m_sessions.enumerate();

        while (enm.hasMoreElements())
        {

            // Get the session id and associated session

            Integer sessId = enm.nextElement();
            SMBSrvSession sess = (SMBSrvSession) m_sessions.findSession(sessId);

            // Inform listeners that the session has been closed

            fireSessionClosedEvent(sess);

            // Close the session

            sess.closeSession();
        }

        // Wait for the main server thread to close

        if (m_srvThread != null)
        {

            try
            {
                m_srvThread.join(3000);
            }
            catch (Exception ex)
            {
            }
        }

        // Fire a shutdown notification event

        fireServerEvent(ServerListener.ServerShutdown);
    }

    /**
     * Start the SMB server in a seperate thread
     */
    public void startServer()
    {

        // Create a seperate thread to run the SMB server

        m_srvThread = new Thread(this);
        m_srvThread.setName("SMB Server");
        m_srvThread.setDaemon(true);

        m_srvThread.start();

        // Fire a server startup event

        fireServerEvent(ServerListener.ServerStartup);
    }

    /**
     * Determine if we are running under Windows NT onwards
     * 
     * @return boolean
     */
    private final boolean isWindowsNTOnwards()
    {

        // Get the operating system name property

        String osName = System.getProperty("os.name");

        if (osName.startsWith("Windows"))
        {
            if (osName.endsWith("95") || osName.endsWith("98") || osName.endsWith("ME"))
            {

                // Windows 95-ME

                return false;
            }

            // Looks like Windows NT onwards

            return true;
        }

        // Not Windows

        return false;
    }

    /**
     * Get the list of local IP addresses
     */
    private final void getServerIPAddresses()
    {

        try
        {

            // Get the local IP address list

            Enumeration<NetworkInterface> enm = NetworkInterface.getNetworkInterfaces();
            Vector<InetAddress> addrList = new Vector<InetAddress>();

            while (enm.hasMoreElements())
            {

                // Get the current network interface

                NetworkInterface ni = enm.nextElement();

                // Get the address list for the current interface

                Enumeration<InetAddress> addrs = ni.getInetAddresses();

                while (addrs.hasMoreElements())
                    addrList.add(addrs.nextElement());
            }

            // Convert the vector of addresses to an array

            if (addrList.size() > 0)
            {

                // Convert the address vector to an array

                InetAddress[] inetAddrs = new InetAddress[addrList.size()];

                // Copy the address details to the array

                for (int i = 0; i < addrList.size(); i++)
                    inetAddrs[i] = (InetAddress) addrList.elementAt(i);

                // Set the server IP address list

                setServerAddresses(inetAddrs);
            }
        }
        catch (Exception ex)
        {

            // DEBUG

            logger.error("Error getting local IP addresses", ex);
        }
    }
    
    /**
     * Return the server GUID
     * 
     * @return UUID
     */
    public final UUID getServerGUID()
    {
        return m_serverGUID;
    }
}