/*
 * Copyright (C) 2005-2010 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.repo.webdav;

import java.util.LinkedList;

import javax.servlet.http.HttpServletResponse;

import org.alfresco.model.ContentModel;
import org.alfresco.model.WebDAVModel;
import org.alfresco.service.cmr.lock.LockService;
import org.alfresco.service.cmr.lock.LockStatus;
import org.alfresco.service.cmr.model.FileInfo;
import org.alfresco.service.cmr.model.FileNotFoundException;
import org.alfresco.service.cmr.repository.NodeService;

/**
 * Implements the WebDAV UNLOCK method
 * 
 * @author gavinc
 */
public class UnlockMethod extends WebDAVMethod
{
    private String m_strLockToken = null;

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

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

    /**
     * Parse the request headers
     * 
     * @exception WebDAVServerException
     */
    protected void parseRequestHeaders() throws WebDAVServerException
    {
        // Get the lock token, if any
        String strLockTokenHeader = m_request.getHeader(WebDAV.HEADER_LOCK_TOKEN);

        // DEBUG
        if (logger.isDebugEnabled())
            logger.debug("Parsing Lock-Token header: " + strLockTokenHeader);

        // Validate the lock token
        if (strLockTokenHeader != null && strLockTokenHeader.startsWith("<") && strLockTokenHeader.endsWith(">"))
        {
            try
            {
                m_strLockToken = strLockTokenHeader.substring(
                        WebDAV.OPAQUE_LOCK_TOKEN.length() + 1,
                        strLockTokenHeader.length() - 1);
            }
            catch (IndexOutOfBoundsException e)
            {
                logger.warn("Failed to parse If header: " + strLockTokenHeader);
            }
        }

        // If there is no token this is a bad request so send an error back
        if (m_strLockToken == null)
        {
            throw new WebDAVServerException(HttpServletResponse.SC_BAD_REQUEST);
        }
    }

    /**
     * Parse the request body
     * 
     * @exception WebDAVServerException
     */
    protected void parseRequestBody() throws WebDAVServerException
    {
        // Nothing to do in this method
    }

    /**
     * Execute the request
     * 
     * @exception WebDAVServerException
     */
    protected void executeImpl() throws WebDAVServerException
    {
        if (logger.isDebugEnabled())
        {
            logger.debug("Lock node; path=" + getPath() + ", token=" + getLockToken());
        }

        FileInfo lockNodeInfo = null;
        try
        {
            lockNodeInfo = getNodeForPath(getRootNodeRef(), getPath(), getServletPath());
        }
        catch (FileNotFoundException e)
        {
            throw new WebDAVServerException(HttpServletResponse.SC_NOT_FOUND);
        }

        // Parse the lock token
        String[] lockInfo = WebDAV.parseLockToken(getLockToken());
        if (lockInfo == null)
        {
            // Bad lock token
            throw new WebDAVServerException(HttpServletResponse.SC_PRECONDITION_FAILED);
        }

        // Get the lock status for the node
        LockService lockService = getDAVHelper().getLockService();
        NodeService nodeService = getNodeService();
        // String nodeId = lockInfo[0];
        // String userName = lockInfo[1];

        LockStatus lockSts = lockService.getLockStatus(lockNodeInfo.getNodeRef());
        if (lockSts == LockStatus.LOCK_OWNER)
        {
            lockService.unlock(lockNodeInfo.getNodeRef());
            nodeService.removeProperty(lockNodeInfo.getNodeRef(), WebDAVModel.PROP_OPAQUE_LOCK_TOKEN);
            nodeService.removeProperty(lockNodeInfo.getNodeRef(), WebDAVModel.PROP_LOCK_DEPTH);
            nodeService.removeProperty(lockNodeInfo.getNodeRef(), WebDAVModel.PROP_LOCK_SCOPE);

            // Return the cm:lockable aspect to working copy (ALF-4479, ALF-7079)
            if (nodeService.hasAspect(lockNodeInfo.getNodeRef(), ContentModel.ASPECT_WORKING_COPY))
            {
                nodeService.addAspect(lockNodeInfo.getNodeRef(), ContentModel.ASPECT_LOCKABLE, null);
            }

            // Indicate that the unlock was successful
            m_response.setStatus(HttpServletResponse.SC_NO_CONTENT);

            // DEBUG
            if (logger.isDebugEnabled())
            {
                logger.debug("Unlock token=" + getLockToken() + " Successful");
            }
        }
        else if (lockSts == LockStatus.NO_LOCK)
        {
            String sharedLocks = (String) nodeService.getProperty(lockNodeInfo.getNodeRef(), WebDAVModel.PROP_SHARED_LOCK_TOKENS);
            if (sharedLocks != null)
            {
                LinkedList<String> locks = LockInfo.parseSharedLockTokens(sharedLocks);
                
                if (locks != null && locks.contains(m_strLockToken))
                {
                    locks.remove(m_strLockToken);
                    nodeService.setProperty(lockNodeInfo.getNodeRef(), WebDAVModel.PROP_SHARED_LOCK_TOKENS, LockInfo.makeSharedLockTokensString(locks));

                    // Indicate that the unlock was successful
                    m_response.setStatus(HttpServletResponse.SC_NO_CONTENT);

                    // DEBUG
                    if (logger.isDebugEnabled())
                    {
                        logger.debug("Unlock token=" + getLockToken() + " Successful");
                    }
                }
            }
            else
            {
            // DEBUG
            if (logger.isDebugEnabled())
                logger.debug("Unlock token=" + getLockToken() + " Not locked");

            // Node is not locked
            throw new WebDAVServerException(HttpServletResponse.SC_PRECONDITION_FAILED);
        }
            
            
        }
        else if (lockSts == LockStatus.LOCKED)
        {
            // DEBUG
            if (logger.isDebugEnabled())
                logger.debug("Unlock token=" + getLockToken() + " Not lock owner");

            // Node is locked but not by this user
            throw new WebDAVServerException(HttpServletResponse.SC_PRECONDITION_FAILED);
        }
        else if (lockSts == LockStatus.LOCK_EXPIRED)
        {
            // DEBUG
            if (logger.isDebugEnabled())
                logger.debug("Unlock token=" + getLockToken() + " Lock expired");

            // Return a success status
            m_response.setStatus(HttpServletResponse.SC_NO_CONTENT);
        }
    }
}