/*
 * Copyright 2012 LinkedIn Corp.
 * 
 * Licensed 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 azkaban.webapp.servlet;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

import javax.management.MBeanAttributeInfo;
import javax.management.MBeanInfo;
import javax.management.ObjectName;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.Logger;

import azkaban.executor.ConnectorParams;
import azkaban.executor.ExecutorManager;
import azkaban.executor.ExecutorManagerAdapter;
import azkaban.trigger.TriggerManager;
import azkaban.user.Permission;
import azkaban.user.Role;
import azkaban.user.User;
import azkaban.user.UserManager;
import azkaban.webapp.AzkabanWebServer;
import azkaban.webapp.session.Session;

/**
 * Limited set of jmx calls for when you cannot attach to the jvm
 */
public class JMXHttpServlet extends LoginAbstractAzkabanServlet implements ConnectorParams {
	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	private static final Logger logger = Logger.getLogger(JMXHttpServlet.class.getName());

	private UserManager userManager;
	private AzkabanWebServer server;
	private ExecutorManagerAdapter executorManager;
	private TriggerManager triggerManager;
	
	@Override
	public void init(ServletConfig config) throws ServletException {
		super.init(config);
		
		server = (AzkabanWebServer)getApplication();
		userManager = server.getUserManager();
		executorManager = server.getExecutorManager();

		triggerManager = server.getTriggerManager();
	}
	
	@Override
	protected void handleGet(HttpServletRequest req, HttpServletResponse resp, Session session) throws ServletException, IOException {
		if (hasParam(req, "ajax")){
			Map<String,Object> ret = new HashMap<String,Object>();

			if(!hasPermission(session.getUser(), Permission.Type.METRICS)) {
				ret.put("error", "User " + session.getUser().getUserId() + " has no permission.");
				this.writeJSON(resp, ret, true);
				return;
			}
			String ajax = getParam(req, "ajax");
			if (JMX_GET_ALL_EXECUTOR_ATTRIBUTES.equals(ajax)) {
				if (!hasParam(req, JMX_MBEAN) || !hasParam(req, JMX_HOSTPORT)) {
					ret.put("error", "Parameters '" + JMX_MBEAN + "' and '"+ JMX_HOSTPORT +"' must be set");
					this.writeJSON(resp, ret, true);
					return;
				}
				
				String hostPort = getParam(req, JMX_HOSTPORT);
				String mbean = getParam(req, JMX_MBEAN);
				Map<String, Object> result = executorManager.callExecutorJMX(hostPort, JMX_GET_ALL_MBEAN_ATTRIBUTES, mbean);
				ret = result;
			}
//			else 
//				if (TriggerConnectorParams.JMX_GET_ALL_TRIGGER_SERVER_ATTRIBUTES.equals(ajax)) {
//				if(!hasParam(req, JMX_MBEAN) || !hasParam(req, JMX_HOSTPORT)) {
//					ret.put("error", "Parameters '" + JMX_MBEAN + "' and '"+ JMX_HOSTPORT +"' must be set");
//					this.writeJSON(resp, ret, true);
//					return;
//				}
////				String hostPort = getParam(req, JMX_HOSTPORT);
////				String mbean = getParam(req, JMX_MBEAN);
//				ret = triggerManager.getJMX().getAllJMXMbeans();
//			}
			else if (JMX_GET_MBEANS.equals(ajax)) {
				ret.put("mbeans", server.getMbeanNames());
			}
			else if (JMX_GET_MBEAN_INFO.equals(ajax)) {
				if (hasParam(req, JMX_MBEAN)) {
					String mbeanName = getParam(req, JMX_MBEAN);
					try {
						ObjectName name = new ObjectName(mbeanName);
						MBeanInfo info = server.getMBeanInfo(name);
						ret.put("attributes", info.getAttributes());
						ret.put("description", info.getDescription());
					} catch (Exception e) {
						logger.error(e);
						ret.put("error", "'" + mbeanName + "' is not a valid mBean name");
					}
				}
				else {
					ret.put("error", "No 'mbean' name parameter specified" );
				}
			}
			else if (JMX_GET_MBEAN_ATTRIBUTE.equals(ajax)) {
				if (!hasParam(req, JMX_MBEAN) || !hasParam(req, JMX_ATTRIBUTE)) {
					ret.put("error", "Parameters 'mbean' and 'attribute' must be set");
				}
				else {
					String mbeanName = getParam(req, JMX_MBEAN);
					String attribute = getParam(req, JMX_ATTRIBUTE);
					
					try {
						ObjectName name = new ObjectName(mbeanName);
						Object obj = server.getMBeanAttribute(name, attribute);
						ret.put("value", obj);
					} catch (Exception e) {
						logger.error(e);
						ret.put("error", "'" + mbeanName + "' is not a valid mBean name");
					}
				}
			}
			else if (JMX_GET_ALL_MBEAN_ATTRIBUTES.equals(ajax)) {
				if (!hasParam(req, JMX_MBEAN)) {
					ret.put("error", "Parameters 'mbean' must be set");
				}
				else {
					String mbeanName = getParam(req, JMX_MBEAN);
					try {
						ObjectName name = new ObjectName(mbeanName);
						MBeanInfo info = server.getMBeanInfo(name);
						
						MBeanAttributeInfo[] mbeanAttrs = info.getAttributes();
						HashMap<String, Object> attributes = new HashMap<String,Object>();

						for (MBeanAttributeInfo attrInfo: mbeanAttrs) {
							Object obj = server.getMBeanAttribute(name, attrInfo.getName());
							attributes.put(attrInfo.getName(), obj);
						}
						
						ret.put("attributes", attributes);
					} catch (Exception e) {
						logger.error(e);
						ret.put("error", "'" + mbeanName + "' is not a valid mBean name");
					}
				}
			}
			else {
				ret.put("commands", new String[] {
						JMX_GET_MBEANS, 
						JMX_GET_MBEAN_INFO+"&"+JMX_MBEAN+"=<name>", 
						JMX_GET_MBEAN_ATTRIBUTE+"&"+JMX_MBEAN+"=<name>&"+JMX_ATTRIBUTE+"=<attributename>"}
				);
			}
			this.writeJSON(resp, ret, true);
		}
		else {
			handleJMXPage(req, resp, session);
		}
	}

	private void handleJMXPage(HttpServletRequest req, HttpServletResponse resp, Session session) throws IOException {
		Page page = newPage(req, resp, session, "azkaban/webapp/servlet/velocity/jmxpage.vm");
		
		if(!hasPermission(session.getUser(), Permission.Type.METRICS)) {
			page.add("errorMsg", "User " + session.getUser().getUserId() + " has no permission.");
			page.render();
			return;
		}

		page.add("mbeans", server.getMbeanNames());
		
		Map<String, Object> executorMBeans = new HashMap<String,Object>();
//		Set<String> primaryServerHosts = executorManager.getPrimaryServerHosts();
		for (String hostPort: executorManager.getAllActiveExecutorServerHosts()) {
			try {
				Map<String, Object> mbeans = executorManager.callExecutorJMX(hostPort, JMX_GET_MBEANS, null);
	
				executorMBeans.put(hostPort, mbeans.get("mbeans"));
//				if (primaryServerHosts.contains(hostPort)) {
//					executorMBeans.put(hostPort, mbeans.get("mbeans"));
//				}
//				else {
//					executorMBeans.put(hostPort, mbeans.get("mbeans"));
//				}
			}
			catch (IOException e) {
				logger.error("Cannot contact executor " + hostPort, e);
			}
		}
		
		page.add("executorRemoteMBeans", executorMBeans);
		
		Map<String, Object> triggerserverMBeans = new HashMap<String,Object>();
//		Set<String> primaryTriggerServerHosts = triggerManager.getPrimaryServerHosts();
//		for (String hostPort: triggerManager.getAllActiveTriggerServerHosts()) {
//			try {
//				Map<String, Object> mbeans = triggerManager.callTriggerServerJMX(hostPort, TriggerConnectorParams.JMX_GET_MBEANS, null);
//				
//				if (primaryTriggerServerHosts.contains(hostPort)) {
//					triggerserverMBeans.put(hostPort, mbeans.get("mbeans"));
//				}
//				else {
//					triggerserverMBeans.put(hostPort, mbeans.get("mbeans"));
//				}
//			}
//			catch (IOException e) {
//				logger.error("Cannot contact executor " + hostPort, e);
//			}
//		}
		triggerserverMBeans.put(triggerManager.getJMX().getPrimaryServerHost(), triggerManager.getJMX().getAllJMXMbeans());
		
		page.add("triggerserverRemoteMBeans", triggerserverMBeans);
		
		page.render();
	}
	
	@Override
	protected void handlePost(HttpServletRequest req, HttpServletResponse resp, Session session) throws ServletException, IOException {

	}
	
//	private boolean hasAdminRole(User user) {
//		for(String roleName: user.getRoles()) {
//			Role role = userManager.getRole(roleName);
//			Permission perm = role.getPermission();
//			if (perm.isPermissionSet(Permission.Type.ADMIN)) {
//				return true;
//			}
//		}
//		
//		return false;
//	}
	
	protected boolean hasPermission(User user, Permission.Type type) {	
		for(String roleName: user.getRoles()) {
			Role role = userManager.getRole(roleName);
			if (role.getPermission().isPermissionSet(type) || role.getPermission().isPermissionSet(Permission.Type.ADMIN)) {
				return true;
			}
		}
		
		return false;
	}
}
