// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// 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 com.cloud.consoleproxy;

import java.io.File;
import java.io.InputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.InetSocketAddress;
import java.net.URISyntaxException;
import java.net.URL;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Hashtable;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.Executor;

import org.apache.axis.encoding.Base64;
import org.apache.log4j.xml.DOMConfigurator;

import com.cloud.consoleproxy.util.Logger;
import com.google.gson.Gson;
import com.sun.net.httpserver.HttpServer;

/**
 * 
 * @author Kelven Yang
 * ConsoleProxy, singleton class that manages overall activities in console proxy process. To make legacy code work, we still
 */
public class ConsoleProxy {
	private static final Logger s_logger = Logger.getLogger(ConsoleProxy.class);
	
	public static final int KEYBOARD_RAW = 0;
	public static final int KEYBOARD_COOKED = 1;
	
	public static int VIEWER_LINGER_SECONDS = 180;
	
	public static Object context;
	
	// this has become more ugly, to store keystore info passed from management server (we now use management server managed keystore to support
	// dynamically changing to customer supplied certificate)
	public static byte[] ksBits;
	public static String ksPassword;
	
	public static Method authMethod;
	public static Method reportMethod;
	public static Method ensureRouteMethod;
	
	static Hashtable<String, ConsoleProxyClient> connectionMap = new Hashtable<String, ConsoleProxyClient>();
	static int httpListenPort = 80;
	static int httpCmdListenPort = 8001;
	static int reconnectMaxRetry = 5;
	static int readTimeoutSeconds = 90;
	static int keyboardType = KEYBOARD_RAW;
	static String factoryClzName;
	static boolean standaloneStart = false;
	
	static String encryptorPassword = genDefaultEncryptorPassword(); 
	
	private static String genDefaultEncryptorPassword() {
		try {
			SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
			
			byte[] randomBytes = new byte[16];
			random.nextBytes(randomBytes);
			return Base64.encode(randomBytes);
		} catch (NoSuchAlgorithmException e) {
			s_logger.error("Unexpected exception ", e);
			assert(false);
		}
		
		return "Dummy";
	}
	
	private static void configLog4j() {
		URL configUrl = System.class.getResource("/conf/log4j-cloud.xml");
		if(configUrl == null)
			configUrl = ClassLoader.getSystemResource("log4j-cloud.xml");
		
		if(configUrl == null)
			configUrl = ClassLoader.getSystemResource("conf/log4j-cloud.xml");
			
		if(configUrl != null) {
			try {
				System.out.println("Configure log4j using " + configUrl.toURI().toString());
			} catch (URISyntaxException e1) {
				e1.printStackTrace();
			}

			try {
				File file = new File(configUrl.toURI());
				
				System.out.println("Log4j configuration from : " + file.getAbsolutePath());
				DOMConfigurator.configureAndWatch(file.getAbsolutePath(), 10000);
			} catch (URISyntaxException e) {
				System.out.println("Unable to convert log4j configuration Url to URI");
			}
			// DOMConfigurator.configure(configUrl);
		} else {
			System.out.println("Configure log4j with default properties");
		}
	}
	
	private static void configProxy(Properties conf) {
		s_logger.info("Configure console proxy...");
		for(Object key : conf.keySet()) {
			s_logger.info("Property " + (String)key + ": " + conf.getProperty((String)key));
		}
		
		String s = conf.getProperty("consoleproxy.httpListenPort");
		if (s!=null) {
			httpListenPort = Integer.parseInt(s);
			s_logger.info("Setting httpListenPort=" + s);
		}
		
		s = conf.getProperty("premium");
		if(s != null && s.equalsIgnoreCase("true")) {
			s_logger.info("Premium setting will override settings from consoleproxy.properties, listen at port 443");
			httpListenPort = 443;
			factoryClzName = "com.cloud.consoleproxy.ConsoleProxySecureServerFactoryImpl";
		} else {
			factoryClzName = ConsoleProxyBaseServerFactoryImpl.class.getName();
		}
		
		s = conf.getProperty("consoleproxy.httpCmdListenPort");
		if (s!=null) {
			httpCmdListenPort = Integer.parseInt(s);
			s_logger.info("Setting httpCmdListenPort=" + s);
		}
		
		s = conf.getProperty("consoleproxy.reconnectMaxRetry");
		if (s!=null) {
			reconnectMaxRetry = Integer.parseInt(s);
			s_logger.info("Setting reconnectMaxRetry=" + reconnectMaxRetry);
		}
		
		s = conf.getProperty("consoleproxy.readTimeoutSeconds");
		if (s!=null) {
			readTimeoutSeconds = Integer.parseInt(s);
			s_logger.info("Setting readTimeoutSeconds=" + readTimeoutSeconds);
		}
	}
	
	public static ConsoleProxyServerFactory getHttpServerFactory() {
		try {
			Class<?> clz = Class.forName(factoryClzName);
			try {
				ConsoleProxyServerFactory factory = (ConsoleProxyServerFactory)clz.newInstance();
				factory.init(ConsoleProxy.ksBits, ConsoleProxy.ksPassword);
				return factory;
			} catch (InstantiationException e) {
				s_logger.error(e.getMessage(), e);
				return null;
			} catch (IllegalAccessException e) {
				s_logger.error(e.getMessage(), e);
				return null;
			}
		} catch (ClassNotFoundException e) {
			s_logger.warn("Unable to find http server factory class: " + factoryClzName);
			return new ConsoleProxyBaseServerFactoryImpl();
		}
	}

	public static ConsoleProxyAuthenticationResult authenticateConsoleAccess(ConsoleProxyClientParam param, boolean reauthentication) {

		ConsoleProxyAuthenticationResult authResult = new ConsoleProxyAuthenticationResult();
		authResult.setSuccess(true);
		authResult.setReauthentication(reauthentication);
		authResult.setHost(param.getClientHostAddress());
		authResult.setPort(param.getClientHostPort());
		
		if(standaloneStart) {
			return authResult;
		}
		
		if(authMethod != null) {
			Object result;
			try {
				result = authMethod.invoke(ConsoleProxy.context, 
					param.getClientHostAddress(), 
					String.valueOf(param.getClientHostPort()), 
					param.getClientTag(), 
					param.getClientHostPassword(), 
					param.getTicket(),
					new Boolean(reauthentication));
			} catch (IllegalAccessException e) {
				s_logger.error("Unable to invoke authenticateConsoleAccess due to IllegalAccessException" + " for vm: " + param.getClientTag(), e);
				authResult.setSuccess(false);
				return authResult;
			} catch (InvocationTargetException e) {
				s_logger.error("Unable to invoke authenticateConsoleAccess due to InvocationTargetException " + " for vm: " + param.getClientTag(), e);
				authResult.setSuccess(false);
				return authResult;
			}
			
			if(result != null && result instanceof String) {
				authResult = new Gson().fromJson((String)result, ConsoleProxyAuthenticationResult.class);
			} else {
				s_logger.error("Invalid authentication return object " + result + " for vm: " + param.getClientTag() + ", decline the access");
				authResult.setSuccess(false);
			}
		} else {
			s_logger.warn("Private channel towards management server is not setup. Switch to offline mode and allow access to vm: " + param.getClientTag());
		}
		
		return authResult;
	}
	
	public static void reportLoadInfo(String gsonLoadInfo) {
		if(reportMethod != null) {
			try {
				reportMethod.invoke(ConsoleProxy.context, gsonLoadInfo);
			} catch (IllegalAccessException e) {
				s_logger.error("Unable to invoke reportLoadInfo due to " + e.getMessage());
			} catch (InvocationTargetException e) {
				s_logger.error("Unable to invoke reportLoadInfo due to " + e.getMessage());
			}
		} else {
			s_logger.warn("Private channel towards management server is not setup. Switch to offline mode and ignore load report");
		}
	}
	
	public static void ensureRoute(String address) {
		if(ensureRouteMethod != null) {
			try {
				ensureRouteMethod.invoke(ConsoleProxy.context, address);
			} catch (IllegalAccessException e) {
				s_logger.error("Unable to invoke ensureRoute due to " + e.getMessage());
			} catch (InvocationTargetException e) {
				s_logger.error("Unable to invoke ensureRoute due to " + e.getMessage());
			}
		} else {
			s_logger.warn("Unable to find ensureRoute method, console proxy agent is not up to date");
		}
	}

	public static void startWithContext(Properties conf, Object context, byte[] ksBits, String ksPassword) {
		s_logger.info("Start console proxy with context");
		if(conf != null) {
			for(Object key : conf.keySet()) {
				s_logger.info("Context property " + (String)key + ": " + conf.getProperty((String)key));
			}
		}
		
		configLog4j();
		Logger.setFactory(new ConsoleProxyLoggerFactory());
		
		// Using reflection to setup private/secure communication channel towards management server
		ConsoleProxy.context = context;
		ConsoleProxy.ksBits = ksBits;
		ConsoleProxy.ksPassword = ksPassword;
		try {
			Class<?> contextClazz = Class.forName("com.cloud.agent.resource.consoleproxy.ConsoleProxyResource");
			authMethod = contextClazz.getDeclaredMethod("authenticateConsoleAccess", String.class, String.class, String.class, String.class, String.class, Boolean.class);
			reportMethod = contextClazz.getDeclaredMethod("reportLoadInfo", String.class);
			ensureRouteMethod = contextClazz.getDeclaredMethod("ensureRoute", String.class);
		} catch (SecurityException e) {
			s_logger.error("Unable to setup private channel due to SecurityException", e);
		} catch (NoSuchMethodException e) {
			s_logger.error("Unable to setup private channel due to NoSuchMethodException", e);
		} catch (IllegalArgumentException e) {
			s_logger.error("Unable to setup private channel due to IllegalArgumentException", e);
		} catch(ClassNotFoundException e) {
			s_logger.error("Unable to setup private channel due to ClassNotFoundException", e);
		}
		
		// merge properties from conf file
		InputStream confs = ConsoleProxy.class.getResourceAsStream("/conf/consoleproxy.properties");
		Properties props = new Properties();
		if (confs == null) {
			s_logger.info("Can't load consoleproxy.properties from classpath, will use default configuration");
		} else {
			try {
				props.load(confs);
				
				for(Object key : props.keySet()) {
					// give properties passed via context high priority, treat properties from consoleproxy.properties
					// as default values
					if(conf.get(key) == null)
						conf.put(key, props.get(key));
				}
			}  catch (Exception e) {
				s_logger.error(e.toString(), e);
			}
		}
		
		start(conf);
	}

	public static void start(Properties conf) {
		System.setProperty("java.awt.headless", "true");
		
		configProxy(conf);
		
		ConsoleProxyServerFactory factory = getHttpServerFactory();
		if(factory == null) {
			s_logger.error("Unable to load console proxy server factory");
			System.exit(1);
		}
		
		if(httpListenPort != 0) {
			startupHttpMain();
		} else {
			s_logger.error("A valid HTTP server port is required to be specified, please check your consoleproxy.httpListenPort settings");
			System.exit(1);
		}
		
	    if(httpCmdListenPort > 0) {
	    	startupHttpCmdPort();
	    } else {
	    	s_logger.info("HTTP command port is disabled");
	    }
	    
	    ConsoleProxyGCThread cthread = new ConsoleProxyGCThread(connectionMap);
		cthread.setName("Console Proxy GC Thread");
		cthread.start();
	}
	
	private static void startupHttpMain() {
		try {
			ConsoleProxyServerFactory factory = getHttpServerFactory();
			if(factory == null) {
				s_logger.error("Unable to load HTTP server factory");
				System.exit(1);
			}
			
			HttpServer server = factory.createHttpServerInstance(httpListenPort);
			server.createContext("/getscreen", new ConsoleProxyThumbnailHandler());
			server.createContext("/resource/", new ConsoleProxyResourceHandler());
			server.createContext("/ajax", new ConsoleProxyAjaxHandler());
			server.createContext("/ajaximg", new ConsoleProxyAjaxImageHandler());
			server.setExecutor(new ThreadExecutor()); // creates a default executor
			server.start();
		} catch(Exception e) {
			s_logger.error(e.getMessage(), e);
			System.exit(1);
		}
	}
	
	private static void startupHttpCmdPort() {
		try {
		    s_logger.info("Listening for HTTP CMDs on port " + httpCmdListenPort);
			HttpServer cmdServer = HttpServer.create(new InetSocketAddress(httpCmdListenPort), 2);
			cmdServer.createContext("/cmd", new ConsoleProxyCmdHandler());
			cmdServer.setExecutor(new ThreadExecutor()); // creates a default executor
			cmdServer.start();
		} catch(Exception e) {
			s_logger.error(e.getMessage(), e);
			System.exit(1);
		}
	}
	
	public static void main(String[] argv) {
		standaloneStart = true;
		configLog4j();
		Logger.setFactory(new ConsoleProxyLoggerFactory());
		
		InputStream confs = ConsoleProxy.class.getResourceAsStream("/conf/consoleproxy.properties");
		Properties conf = new Properties();
		if (confs == null) {
			s_logger.info("Can't load consoleproxy.properties from classpath, will use default configuration");
		} else {
			try {
				conf.load(confs);
			}  catch (Exception e) {
				s_logger.error(e.toString(), e);
			}
		}
		start(conf);
	}
	
	public static ConsoleProxyClient getVncViewer(ConsoleProxyClientParam param) throws Exception {
		ConsoleProxyClient viewer = null;
		
		boolean reportLoadChange = false;
		String clientKey = param.getClientMapKey();
		synchronized (connectionMap) {
			viewer = connectionMap.get(clientKey);
			if (viewer == null) {
				viewer = new ConsoleProxyVncClient();
				viewer.initClient(param);
				connectionMap.put(clientKey, viewer);
				s_logger.info("Added viewer object " + viewer);
				
				reportLoadChange = true;
			} else if (!viewer.isFrontEndAlive()) {
				s_logger.info("The rfb thread died, reinitializing the viewer " + viewer);
				viewer.initClient(param);
			} else if (!param.getClientHostPassword().equals(viewer.getClientHostPassword())) {
				s_logger.warn("Bad sid detected(VNC port may be reused). sid in session: " + viewer.getClientHostPassword()
					+ ", sid in request: " + param.getClientHostPassword());
				viewer.initClient(param);
			}
		}
		
		if(reportLoadChange) {
			ConsoleProxyClientStatsCollector statsCollector = getStatsCollector();
			String loadInfo = statsCollector.getStatsReport();
			reportLoadInfo(loadInfo);
			if(s_logger.isDebugEnabled())
				s_logger.debug("Report load change : " + loadInfo);
		}
		
		return viewer;
	}
	
	public static ConsoleProxyClient getAjaxVncViewer(ConsoleProxyClientParam param, String ajaxSession) throws Exception {
		
		boolean reportLoadChange = false;
		String clientKey = param.getClientMapKey();
		synchronized (connectionMap) {
			ConsoleProxyClient viewer = connectionMap.get(clientKey);
			if (viewer == null) {
				viewer = new ConsoleProxyVncClient();
				viewer.initClient(param);
				
				connectionMap.put(clientKey, viewer);
				s_logger.info("Added viewer object " + viewer);
				reportLoadChange = true;
			} else if (!viewer.isFrontEndAlive()) {
				s_logger.info("The rfb thread died, reinitializing the viewer " + viewer);
				viewer.initClient(param);
			} else if (!param.getClientHostPassword().equals(viewer.getClientHostPassword())) {
				s_logger.warn("Bad sid detected(VNC port may be reused). sid in session: " 
					+ viewer.getClientHostPassword() + ", sid in request: " + param.getClientHostPassword());
				viewer.initClient(param);
			} else {
				if(ajaxSession == null || ajaxSession.isEmpty())
					authenticationExternally(param);
			}
			
			if(reportLoadChange) {
				ConsoleProxyClientStatsCollector statsCollector = getStatsCollector();
				String loadInfo = statsCollector.getStatsReport();
				reportLoadInfo(loadInfo);
				if(s_logger.isDebugEnabled())
					s_logger.debug("Report load change : " + loadInfo);
			}
			return viewer;
		}
	}
	
	public static void removeViewer(ConsoleProxyClient viewer) {
		synchronized (connectionMap) {
			for(Map.Entry<String, ConsoleProxyClient> entry : connectionMap.entrySet()) {
				if(entry.getValue() == viewer) {
					connectionMap.remove(entry.getKey());
					return;
				}
			}
		}
	}
	
	public static ConsoleProxyClientStatsCollector getStatsCollector() {
		return new ConsoleProxyClientStatsCollector(connectionMap);
	}
	
	public static void authenticationExternally(ConsoleProxyClientParam param) throws AuthenticationException {
		ConsoleProxyAuthenticationResult authResult = authenticateConsoleAccess(param, false);
		
		if(authResult == null || !authResult.isSuccess()) {
    		s_logger.warn("External authenticator failed authencation request for vm " + param.getClientTag() + " with sid " + param.getClientHostPassword());
        	
			throw new AuthenticationException("External authenticator failed request for vm " + param.getClientTag() + " with sid " + param.getClientHostPassword());
		}
	}
	
	public static ConsoleProxyAuthenticationResult reAuthenticationExternally(ConsoleProxyClientParam param) {
		return authenticateConsoleAccess(param, true);
	}
	
	public static String getEncryptorPassword() { 
		return encryptorPassword; 
	}
	
	public static void setEncryptorPassword(String password) {
		encryptorPassword = password;
	}
	
	static class ThreadExecutor implements Executor {
	     public void execute(Runnable r) {
	         new Thread(r).start();
	     }
	}
}