/*
 * Copyright (C) 2005 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.repo.webdav;

import java.util.List;

import javax.servlet.http.HttpServletResponse;

import org.alfresco.model.ContentModel;
import org.alfresco.service.cmr.lock.LockService;
import org.alfresco.service.cmr.lock.LockStatus;
import org.alfresco.service.cmr.lock.LockType;
import org.alfresco.service.cmr.model.FileFolderService;
import org.alfresco.service.cmr.model.FileInfo;
import org.alfresco.service.cmr.model.FileNotFoundException;
import org.alfresco.service.cmr.repository.NodeRef;
import org.dom4j.io.XMLWriter;

/**
 * Implements the WebDAV LOCK method
 * 
 * @author gavinc
 */
public class LockMethod extends WebDAVMethod
{
    private String m_strLockToken = null;
    private int m_timeoutDuration = WebDAV.DEPTH_INFINITY;

    /**
     * Default constructor
     */
    public LockMethod()
    {
    }

    /**
     * Check if the lock token is valid
     * 
     * @return boolean
     */
    protected final boolean hasLockToken()
    {
        return m_strLockToken != null ? true : false;
    }

    /**
     * Return the lock token of an existing lock
     * 
     * @return String
     */
    protected final String getLockToken()
    {
        return m_strLockToken;
    }

    /**
     * Return the lock timeout, in minutes
     * 
     * @return int
     */
    protected final int getLockTimeout()
    {
        return m_timeoutDuration;
    }

    /**
     * Parse the request headers
     * 
     * @exception WebDAVServerException
     */
    protected void parseRequestHeaders() throws WebDAVServerException
    {
        // Get the lock token, if any

        m_strLockToken = parseIfHeader();

        // Get the lock timeout value

        String strTimeout = m_request.getHeader(WebDAV.HEADER_TIMEOUT);

        // If the timeout header starts with anything other than Second
        // leave the timeout as the default

        if (strTimeout != null && strTimeout.startsWith(WebDAV.SECOND))
        {
            try
            {
                // Some clients send header as Second-180 Seconds so we need to
                // look for the space

                int idx = strTimeout.indexOf(" ");

                if (idx != -1)
                {
                    // Get the bit after Second- and before the space

                    strTimeout = strTimeout.substring(WebDAV.SECOND.length(), idx);
                }
                else
                {
                    // The string must be in the correct format

                    strTimeout = strTimeout.substring(WebDAV.SECOND.length());
                }
                m_timeoutDuration = Integer.parseInt(strTimeout);
            }
            catch (Exception e)
            {
                // Warn about the parse failure and leave the timeout as the
                // default

                logger.warn("Failed to parse Timeout header: " + strTimeout);
            }
        }

        // DEBUG

        if (logger.isDebugEnabled())
            logger.debug("Lock lockToken=" + getLockToken() + ", timeout=" + getLockTimeout());
    }

    /**
     * Parse the request body
     * 
     * @exception WebDAVServerException
     */
    protected void parseRequestBody() throws WebDAVServerException
    {
        // NOTE: There is a body for lock requests which contain the
        // type of lock to apply and the lock owner but we will
        // ignore these settings so don't bother reading the body
    }

    /**
     * Exceute the request
     * 
     * @exception WebDAVServerException
     */
    protected void executeImpl() throws WebDAVServerException, Exception
    {
        FileFolderService fileFolderService = getFileFolderService();
        String path = getPath();
        NodeRef rootNodeRef = getRootNodeRef();
        // Get the active user
        String userName = getDAVHelper().getAuthenticationService().getCurrentUserName();

        if (logger.isDebugEnabled())
        {
            logger.debug("Locking node: \n" +
                    "   user: " + userName + "\n" +
                    "   path: " + path);
        }

        FileInfo lockNodeInfo = null;
        try
        {
            // Check if the path exists
            lockNodeInfo = getDAVHelper().getNodeForPath(getRootNodeRef(), getPath(), m_request.getServletPath());
        }
        catch (FileNotFoundException e)
        {
            // need to create it
            String[] splitPath = getDAVHelper().splitPath(path);
            // check
            if (splitPath[1].length() == 0)
            {
                throw new WebDAVServerException(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            }
            
            List<String> dirPathElements = getDAVHelper().splitAllPaths(splitPath[0]);
            FileInfo dirInfo = fileFolderService.makeFolders(rootNodeRef, dirPathElements, ContentModel.TYPE_FOLDER);
            if (dirInfo == null)
            {
                throw new WebDAVServerException(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            }
            // create the file
            lockNodeInfo = fileFolderService.create(dirInfo.getNodeRef(), splitPath[1], ContentModel.TYPE_CONTENT);
            
            if (logger.isDebugEnabled())
            {
                logger.debug("Created new node for lock: \n" +
                        "   path: " + path + "\n" +
                        "   node: " + lockNodeInfo);
            }
        }


        // Check if this is a new lock or a refresh
        if (hasLockToken())
        {
            // Refresh an existing lock
            refreshLock(lockNodeInfo.getNodeRef(), userName);
        }
        else
        {
            // Create a new lock
            createLock(lockNodeInfo.getNodeRef(), userName);
        }

        // We either created a new lock or refreshed an existing lock, send back the lock details
        generateResponse(lockNodeInfo.getNodeRef(), userName);
    }

    /**
     * Create a new lock
     * 
     * @param lockNode NodeRef
     * @param userName String
     * @exception WebDAVServerException
     */
    private final void createLock(NodeRef lockNode, String userName) throws WebDAVServerException
    {
        LockService lockService = getLockService();

        // Check the lock status of the node
        LockStatus lockSts = lockService.getLockStatus(lockNode);

        // DEBUG
        if (logger.isDebugEnabled())
            logger.debug("Create lock status=" + lockSts);

        if (lockSts == LockStatus.LOCKED || lockSts == LockStatus.LOCK_OWNER)
        {
            // Indicate that the resource is already locked
            throw new WebDAVServerException(WebDAV.WEBDAV_SC_LOCKED);
        }

        // Lock the node
        lockService.lock(lockNode, LockType.WRITE_LOCK, getLockTimeout());
    }

    /**
     * Refresh an existing lock
     * 
     * @param lockNode NodeRef
     * @param userName String
     * @exception WebDAVServerException
     */
    private final void refreshLock(NodeRef lockNode, String userName) throws WebDAVServerException
    {
        LockService lockService = getLockService();

        // Check the lock status of the node
        LockStatus lockSts = lockService.getLockStatus(lockNode);

        // DEBUG
        if (logger.isDebugEnabled())
            logger.debug("Refresh lock status=" + lockSts);

        if (lockSts != LockStatus.LOCK_OWNER)
        {
            // Indicate that the resource is already locked
            throw new WebDAVServerException(WebDAV.WEBDAV_SC_LOCKED);
        }

        // Update the expiry for the lock
        lockService.lock(lockNode, LockType.WRITE_LOCK, getLockTimeout());
    }

    /**
     * Generates the XML lock discovery response body
     */
    private void generateResponse(NodeRef lockNode, String userName) throws Exception
    {
        XMLWriter xml = createXMLWriter();

        xml.startDocument();

        String nsdec = generateNamespaceDeclarations(null);
        xml.startElement(WebDAV.DAV_NS, WebDAV.XML_MULTI_STATUS + nsdec, WebDAV.XML_NS_MULTI_STATUS + nsdec,
                getDAVHelper().getNullAttributes());

        // Output the lock details
        generateLockDiscoveryXML(xml, lockNode);

        // Close off the XML
        xml.endElement(WebDAV.DAV_NS, WebDAV.XML_MULTI_STATUS, WebDAV.XML_NS_MULTI_STATUS);

        // Send the XML back to the client
        m_response.setStatus(HttpServletResponse.SC_OK);
        xml.flush();
    }
}