/*******************************************************************************
 * This file is part of OpenNMS(R).
 *
 * Copyright (C) 2006-2012 The OpenNMS Group, Inc.
 * OpenNMS(R) is Copyright (C) 1999-2012 The OpenNMS Group, Inc.
 *
 * OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc.
 *
 * OpenNMS(R) is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published
 * by the Free Software Foundation, either version 3 of the License,
 * or (at your option) any later version.
 *
 * OpenNMS(R) 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with OpenNMS(R).  If not, see:
 *      http://www.gnu.org/licenses/
 *
 * For more information contact:
 *     OpenNMS(R) Licensing <license@opennms.org>
 *     http://www.opennms.org/
 *     http://www.opennms.com/
 *******************************************************************************/

package org.opennms.web.nodelabel;

import java.io.IOException;
import java.sql.SQLException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.opennms.netmgt.EventConstants;
import org.opennms.netmgt.dao.NodeDao;
import org.opennms.netmgt.model.events.EventBuilder;
import org.opennms.netmgt.model.OnmsNode;
import org.opennms.netmgt.model.events.EventProxy;
import org.opennms.netmgt.model.events.EventProxyException;
import org.opennms.netmgt.utils.NodeLabel;
import org.opennms.web.MissingParameterException;
import org.opennms.web.WebSecurityUtils;
import org.opennms.web.api.Util;
import org.opennms.web.rest.MultivaluedMapImpl;
import org.opennms.web.rest.RequisitionRestService;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.support.TransactionCallback;
import org.springframework.transaction.support.TransactionTemplate;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

/**
 * Changes the label of a node, throws an event signaling that change, and then
 * redirects the user to a web page displaying that node's details.
 *
 * @author <A HREF="larry@opennms.org">Larry Karnowski</A>
 * @author <A HREF="http://www.opennms.org/">OpenNMS</A>
 */
public class NodeLabelChangeServlet extends HttpServlet {

    /**
     * 
     */
    private static final long serialVersionUID = -7766362068448931124L;
    protected EventProxy proxy;

    /**
     * <p>init</p>
     *
     * @throws javax.servlet.ServletException if any.
     */
    public void init() throws ServletException {
        try {
            this.proxy = Util.createEventProxy();
        } catch (Throwable e) {
            throw new ServletException("JMS Exception", e);
        }
    }

    /** {@inheritDoc} */
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String nodeIdString = request.getParameter("node");
        String labelType = request.getParameter("labeltype");
        String userLabel = request.getParameter("userlabel");

        if (nodeIdString == null) {
            throw new MissingParameterException("node", new String[] { "node", "labeltype", "userlabel" });
        }
        if (labelType == null) {
            throw new MissingParameterException("labeltype", new String[] { "node", "labeltype", "userlabel" });
        }
        if (userLabel == null) {
            throw new MissingParameterException("userlabel", new String[] { "node", "labeltype", "userlabel" });
        }

        try {
            final int nodeId = WebSecurityUtils.safeParseInt(nodeIdString);
            NodeLabel oldLabel = NodeLabel.retrieveLabel(nodeId);
            NodeLabel newLabel = null;

            if (labelType.equals("auto")) {
                newLabel = NodeLabel.computeLabel(nodeId);
            } else if (labelType.equals("user")) {
                newLabel = new NodeLabel(userLabel, NodeLabel.SOURCE_USERDEFINED);
            } else {
                throw new ServletException("Unexpected labeltype value: " + labelType);
            }

            WebApplicationContext beanFactory = WebApplicationContextUtils.getWebApplicationContext(getServletContext());
            TransactionTemplate transactionTemplate = beanFactory.getBean(TransactionTemplate.class);
            final RequisitionRestService requisitionService = beanFactory.getBean(RequisitionRestService.class);
            final NodeDao nodeDao = beanFactory.getBean(NodeDao.class);

            final String newNodeLabel = newLabel.getLabel();
            String foreignSource = transactionTemplate.execute(new TransactionCallback<String>() {
                public String doInTransaction(TransactionStatus status) {
                    OnmsNode node = nodeDao.get(nodeId);
                    if (node.getForeignSource() != null && node.getForeignId() != null) {
                        MultivaluedMapImpl params = new MultivaluedMapImpl();
                        params.putSingle("node-label", newNodeLabel);
                        requisitionService.updateNode(node.getForeignSource(), node.getForeignId(), params);
                        return node.getForeignSource();
                    }
                    return null;
                }
            });

            this.sendLabelChangeEvent(nodeId, oldLabel, newLabel);

            if (foreignSource != null) {
                response.sendRedirect(Util.calculateUrlBase(request, "admin/nodelabelProvisioned.jsp?node=" + nodeIdString + "&foreignSource=" + foreignSource));
            } else {
                NodeLabel.assignLabel(nodeId, newLabel);
                response.sendRedirect(Util.calculateUrlBase(request, "element/node.jsp?node=" + nodeIdString));
            }
        } catch (SQLException e) {
            throw new ServletException("Database exception", e);
        } catch (Throwable e) {
            throw new ServletException("Exception sending node label change event", e);
        }
    }

    /**
     * <p>sendLabelChangeEvent</p>
     *
     * @param nodeId a int.
     * @param oldNodeLabel a {@link org.opennms.netmgt.utils.NodeLabel} object.
     * @param newNodeLabel a {@link org.opennms.netmgt.utils.NodeLabel} object.
     * @throws org.opennms.netmgt.model.events.EventProxyException if any.
     */
    protected void sendLabelChangeEvent(int nodeId, NodeLabel oldNodeLabel, NodeLabel newNodeLabel) throws EventProxyException {
        
        EventBuilder bldr = new EventBuilder(EventConstants.NODE_LABEL_CHANGED_EVENT_UEI, "NodeLabelChangeServlet");

        bldr.setNodeid(nodeId);
        bldr.setHost("host");

        if (oldNodeLabel != null) {
            bldr.addParam(EventConstants.PARM_OLD_NODE_LABEL, oldNodeLabel.getLabel());
            bldr.addParam(EventConstants.PARM_OLD_NODE_LABEL_SOURCE,oldNodeLabel.getSource() );
        }

        if (newNodeLabel != null) {
            bldr.addParam(EventConstants.PARM_NEW_NODE_LABEL, newNodeLabel.getLabel());
            bldr.addParam(EventConstants.PARM_NEW_NODE_LABEL_SOURCE, newNodeLabel.getSource());
        }

        this.proxy.send(bldr.getEvent());
    }

}
