/*
 * Copyright (C) 2006-2010 Alfresco Software Limited.
 *
 * This file is part of Alfresco
 *
 * Alfresco is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Alfresco is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.
 */

package org.alfresco.jlan.app;

import java.io.File;
import java.io.PrintStream;
import java.lang.reflect.Constructor;
import java.net.InetAddress;
import java.net.UnknownHostException;

import org.alfresco.jlan.debug.Debug;
import org.alfresco.jlan.debug.DebugConfigSection;
import org.alfresco.jlan.netbios.server.NetBIOSNameServer;
import org.alfresco.jlan.netbios.win32.Win32NetBIOS;
import org.alfresco.jlan.server.NetworkServer;
import org.alfresco.jlan.server.ServerListener;
import org.alfresco.jlan.server.config.ServerConfiguration;
import org.alfresco.jlan.smb.SMBErrorText;
import org.alfresco.jlan.smb.SMBStatus;
import org.alfresco.jlan.smb.server.CIFSConfigSection;
import org.alfresco.jlan.smb.server.SMBServer;
import org.alfresco.jlan.smb.util.DriveMapping;
import org.alfresco.jlan.smb.util.DriveMappingList;
import org.alfresco.jlan.util.ConsoleIO;
import org.alfresco.jlan.util.Platform;
import org.alfresco.jlan.util.win32.Win32Utils;

/**
 * JLAN CIFS Server Application
 * 
 * @author gkspencer
 */
public class JLANCifsServer implements ServerListener {

	// Constants
	//
	// Checkpoints

	public static final int CheckPointStarting = 0;
	public static final int CheckPointConfigLoading = 1;
	public static final int CheckPointConfigLoaded = 2;
	public static final int CheckPointCheckIPAddress = 3;
	public static final int CheckPointCreateSMBServer = 4;
	public static final int CheckPointServersStart = 5;
	public static final int CheckPointServersStarted = 6;
	public static final int CheckPointRunning = 7;
	public static final int CheckPointServersStop = 8;
	public static final int CheckPointServersStopped = 9;
	public static final int CheckPointFinished = 10;

	// Default configuration file name

	private static final String DEFAULT_CONFIGFILENAME = "jlanserver.xml";

	// Flag to enable/disable local IP address checking

	private static final boolean CheckLocalIPAddress = false;

	// Server shutdown flag

	protected static boolean m_shutdown = false;

	// Server restart flag

	protected static boolean m_restart = false;

	// Flag to enable user to shutdown the server via the console

	protected static boolean m_allowShutViaConsole = true;

	// Flag to control output of a stacktrace if an error occurs

	protected static boolean m_dumpStackOnError = true;

	// Server configuration

	private ServerConfiguration m_srvConfig;

	/**
	 * Start the JLAN Server
	 * 
	 * @param args an array of command-line arguments
	 */
	public static void main(String[] args) {

		// Create the main JLANServer object

		JLANCifsServer jlanServer = new JLANCifsServer();

		// Loop until shutdown

		while (m_shutdown == false) {

			// Start the server

			jlanServer.start(args);

			// DEBUG

			if ( Debug.EnableInfo && m_restart == true) {
				Debug.println("Restarting server ...");
				Debug.println("--------------------------------------------------");
			}
		}
	}

	/**
	 * Class constructor
	 */
	protected JLANCifsServer() {
	}

	/**
	 * Set/clear the allow shutdown via console flag
	 * 
	 * @param consoleShut boolean
	 */
	public static final void setAllowConsoleShutdown(boolean consoleShut) {
		m_allowShutViaConsole = consoleShut;
	}

	/**
	 * Enable/disable exception stack dumps
	 * 
	 * @param ena boolean
	 */
	protected final void enableExceptionStackDump(boolean ena) {
		m_dumpStackOnError = ena;
	}

	/**
	 * Start the JLAN Server
	 * 
	 * @param args String[]
	 */
	protected void start(String[] args) {

		// Command line parameter should specify the configuration file

		PrintStream out = createOutputStream();

		// Clear the shutdown/restart flags

		m_shutdown = true;
		m_restart = false;

		// Checkpoint - server starting

		checkPoint(out, CheckPointStarting);

		// Load the configuration

		m_srvConfig = null;

		try {

			// Checkpoint - configuration loading

			checkPoint(out, CheckPointConfigLoading);

			// Load the configuration

			m_srvConfig = loadConfiguration(out, args);

			// Checkpoint - configuration loaded

			checkPoint(out, CheckPointConfigLoaded);
		}
		catch (Exception ex) {

			// Failed to load server configuration

			checkPointError(out, CheckPointConfigLoading, ex);
			return;
		}

		// Check if the local IP address returns a valid value, '127.0.0.1' indicates a mis-configuration in the hosts
		// file

		if ( CheckLocalIPAddress) {

			try {

				// Checkpoint - check IP address

				checkPoint(out, CheckPointCheckIPAddress);

				// Get the local address

				String localAddr = InetAddress.getLocalHost().getHostAddress();
				if ( localAddr.equals("127.0.0.1")) {
					out.println("%% Local IP address resolves to 127.0.0.1, this may be caused by a mis-configured hosts file");
					return;
				}
			}
			catch (UnknownHostException ex) {

				// Failed to get local host IP address details

				checkPointError(out, CheckPointCheckIPAddress, ex);
				return;
			}
		}

		// NetBIOS name server, SMB, FTP and NFS servers

		try {

			// Create the SMB server and NetBIOS name server, if enabled

			if ( m_srvConfig.hasConfigSection(CIFSConfigSection.SectionName)) {

				// Checkpoint - create SMB/CIFS server

				checkPoint(out, CheckPointCreateSMBServer);

				// Get the CIFS server configuration

				CIFSConfigSection cifsConfig = (CIFSConfigSection) m_srvConfig.getConfigSection(CIFSConfigSection.SectionName);

				// Load the Win32 NetBIOS library
				//
				// For some strange reason the native code loadLibrary() call hangs if done later by the SMBServer.
				// Forcing the Win32NetBIOS class to load here and run the static initializer fixes the problem.

				if ( cifsConfig.hasWin32NetBIOS())
					Win32NetBIOS.LanaEnumerate();

				// Create the NetBIOS name server if NetBIOS SMB is enabled

				if ( cifsConfig.hasNetBIOSSMB())
					m_srvConfig.addServer(createNetBIOSServer(m_srvConfig));

				// Create the SMB server

				m_srvConfig.addServer(createSMBServer(m_srvConfig));
			}

			// Checkpoint - starting servers

			checkPoint(out, CheckPointServersStart);

			// Get the debug configuration

			DebugConfigSection dbgConfig = (DebugConfigSection) m_srvConfig.getConfigSection(DebugConfigSection.SectionName);

			// Start the configured servers

			for (int i = 0; i < m_srvConfig.numberOfServers(); i++) {

				// Get the current server

				NetworkServer server = m_srvConfig.getServer(i);

				// DEBUG

				if ( Debug.EnableInfo && dbgConfig != null && dbgConfig.hasDebug())
					Debug.println("Starting server " + server.getProtocolName() + " ...");

				// Start the server

				m_srvConfig.getServer(i).startServer();
			}

			// Checkpoint - servers started

			checkPoint(out, CheckPointServersStarted);

			// Check if the server is running as a service

			boolean service = false;

			if ( ConsoleIO.isValid() == false)
				service = true;

			// Checkpoint - servers running

			checkPoint(out, CheckPointRunning);

			// Wait while the server runs, user may stop or restart the server by typing a key

			m_shutdown = false;

			while (m_shutdown == false && m_restart == false) {

				// Check if the user has requested a shutdown, if running interactively

				if ( service == false && m_allowShutViaConsole) {

					// Wait for the user to enter the shutdown key

					int inChar = ConsoleIO.readCharacter();

					if ( inChar == 'x' || inChar == 'X')
						m_shutdown = true;
					else if ( inChar == 'r' || inChar == 'R')
						m_restart = true;
					else if ( inChar == -1) {
						
						// Sleep for a short while

						try {
							Thread.sleep(500);
						}
						catch (InterruptedException ex) {
						}
					}
				}
				else {

					// Sleep for a short while

					try {
						Thread.sleep(500);
					}
					catch (InterruptedException ex) {
					}
				}
			}

			// Checkpoint - servers stopping

			checkPoint(out, CheckPointServersStop);

			// Shutdown the servers

			int idx = m_srvConfig.numberOfServers() - 1;

			while (idx >= 0) {

				// Get the current server

				NetworkServer server = m_srvConfig.getServer(idx--);

				// DEBUG

				if ( Debug.EnableInfo && dbgConfig != null && dbgConfig.hasDebug())
					Debug.println("Shutting server " + server.getProtocolName() + " ...");

				// Stop the server

				server.shutdownServer(false);
			}

			// Close the configuration
			
			m_srvConfig.closeConfiguration();
			
			// Checkpoint - servers stopped

			checkPoint(out, CheckPointServersStopped);
		}
		catch (Exception ex) {

			// Server error

			checkPointError(out, CheckPointServersStarted, ex);
		}
		finally {

			// Close all active servers

			int idx = m_srvConfig.numberOfServers() - 1;

			while (idx >= 0) {
				NetworkServer srv = m_srvConfig.getServer(idx--);
				if ( srv.isActive())
					srv.shutdownServer(true);
			}
		}

		// Checkpoint - finished

		checkPoint(out, CheckPointFinished);
	}

	/**
	 * Shutdown the server when running as an NT service
	 * 
	 * @param args String[]
	 */
	public final static void shutdownServer(String[] args) {
		m_shutdown = true;
	}

	/**
	 * Create the SMB server
	 * 
	 * @param config ServerConfiguration
	 * @return NetworkServer
	 * @exception Exception
	 */
	protected final NetworkServer createSMBServer(ServerConfiguration config)
		throws Exception {

		// Create an SMB server

		NetworkServer smbServer = new SMBServer(config);

		// Check if there are any drive mappings configured

		if ( Platform.isPlatformType() == Platform.Type.WINDOWS
				&& config.hasConfigSection(DriveMappingsConfigSection.SectionName))
			smbServer.addServerListener(this);

		// Return the SMB server

		return smbServer;
	}

	/**
	 * Create the NetBIOS name server
	 * 
	 * @param config ServerConfiguration
	 * @return NetworkServer
	 * @exception Exception
	 */
	protected final NetworkServer createNetBIOSServer(ServerConfiguration config)
		throws Exception {

		// Create a NetBIOS name server

		return new NetBIOSNameServer(config);
	}

	/**
	 * Create a network server using reflection
	 * 
	 * @param className String
	 * @param config ServerConfiguration
	 * @return NetworkServer
	 * @exception Exception
	 */
	protected final NetworkServer createServer(String className, ServerConfiguration config)
		throws Exception {

		// Create the server instance using reflection

		NetworkServer srv = null;

		// Find the server constructor

		Class<?>[] classes = new Class[1];
		classes[0] = ServerConfiguration.class;
		Constructor<?> srvConstructor = Class.forName(className).getConstructor(classes);

		// Create the network server

		Object[] args = new Object[1];
		args[0] = config;
		srv = (NetworkServer) srvConstructor.newInstance(args);

		// Return the network server instance

		return srv;
	}

	/**
	 * Load the server configuration, default is to load using an XML configuration file.
	 * 
	 * @param out PrintStream
	 * @param cmdLineArgs String[]
	 * @return ServerConfiguration
	 * @exception Exception
	 */
	protected ServerConfiguration loadConfiguration(PrintStream out, String[] cmdLineArgs)
		throws Exception {

		String fileName = null;

		if ( cmdLineArgs.length < 1) {

			// Search for a default configuration file in the users home directory

			fileName = System.getProperty("user.home") + File.separator + DEFAULT_CONFIGFILENAME;
		}
		else
			fileName = cmdLineArgs[0];

		// Load the configuration

		ServerConfiguration srvCfg = null;

		// Create an XML configuration

		srvCfg = new XMLServerConfiguration();
		srvCfg.loadConfiguration(fileName);

		// Return the server configuration

		return srvCfg;
	}

	/**
	 * Create the output stream for logging
	 * 
	 * @return PrintStream
	 */
	protected PrintStream createOutputStream() {
		return System.out;
	}

	/**
	 * Checkpoint method, called at various points of the server startup and shutdown
	 * 
	 * @param out PrintStream
	 * @param check int
	 */
	protected void checkPoint(PrintStream out, int check) {
	}

	/**
	 * Checkpoint error method, called if an error occurs during server startup/shutdown
	 * 
	 * @param out PrintStream
	 * @param check int
	 * @param ex Exception
	 */
	protected void checkPointError(PrintStream out, int check, Exception ex) {

		// Default error output goes to the console

		String msg = "%% Error occurred";

		switch (check) {

			// Configuration load error

			case CheckPointConfigLoading:
				msg = "%% Failed to load server configuration";
				break;

			// Checking local network address error

			case CheckPointCheckIPAddress:
				msg = "%% Failed to get local IP address details";
				break;

			//

			case CheckPointServersStarted:
				msg = "%% Server error";
				break;
		}

		// Output the error message and a stack trace

		out.println(msg);
		if ( m_dumpStackOnError)
			ex.printStackTrace(out);
	}

	/**
	 * Handle server startup/shutdown events
	 * 
	 * @param server NetworkServer
	 * @param event int
	 */
	public void serverStatusEvent(NetworkServer server, int event) {

		// Check for an SMB server event

		if ( server instanceof SMBServer) {

			// Get the drive mappings configuration

			DriveMappingsConfigSection mapConfig = (DriveMappingsConfigSection) m_srvConfig
					.getConfigSection(DriveMappingsConfigSection.SectionName);
			if ( mapConfig == null)
				return;

			// Check for a server startup event, add drive mappings now that the server is running

			if ( event == ServerListener.ServerStartup) {

				// Get the mapped drives list

				DriveMappingList mapList = mapConfig.getMappedDrives();

				// Add the mapped drives

				for (int i = 0; i < mapList.numberOfMappings(); i++) {

					// Get the current drive mapping

					DriveMapping driveMap = mapList.getMappingAt(i);

					// DEBUG

					if ( Debug.EnableInfo && mapConfig.hasDebug())
						Debug.println("Mapping drive " + driveMap.getLocalDrive() + " to " + driveMap.getRemotePath() + " ...");

					// Create a local mapped drive to the JLAN Server

					int sts = Win32Utils.MapNetworkDrive(driveMap.getRemotePath(), driveMap.getLocalDrive(), driveMap
							.getUserName(), driveMap.getPassword(), driveMap.hasInteractive(), driveMap.hasPrompt());

					// Check if the drive was mapped successfully

					if ( sts != 0)
						Debug.println("Failed to map drive " + driveMap.getLocalDrive() + " to " + driveMap.getRemotePath()
								+ ", status = " + SMBErrorText.ErrorString(SMBStatus.Win32Err, sts));
				}
			}
			else if ( event == ServerListener.ServerShutdown) {

				// Get the mapped drives list

				DriveMappingList mapList = mapConfig.getMappedDrives();

				// Remove the mapped drives

				for (int i = 0; i < mapList.numberOfMappings(); i++) {

					// Get the current drive mapping

					DriveMapping driveMap = mapList.getMappingAt(i);

					// DEBUG

					if ( Debug.EnableInfo && mapConfig.hasDebug())
						Debug.println("Removing mapped drive " + driveMap.getLocalDrive() + " to " + driveMap.getRemotePath()
								+ " ...");

					// Remove a mapped drive

					int sts = Win32Utils.DeleteNetworkDrive(driveMap.getLocalDrive(), false, true);

					// Check if the drive was unmapped successfully

					if ( sts != 0)
						Debug.println("Failed to delete mapped drive " + driveMap.getLocalDrive() + " from "
								+ driveMap.getRemotePath() + ", status = " + SMBErrorText.ErrorString(SMBStatus.Win32Err, sts));
				}
			}
			// else if (( event & 0xFF) == SMBServer.CIFSNetBIOSNamesAdded)
			// Debug.println("NetBIOS name added event, lana=" + ( event >> 16));
		}
	}

}