/*
 * DavMail POP/IMAP/SMTP/CalDav/LDAP Exchange Gateway
 * Copyright (C) 2009  Mickael Guessant
 *
 * This program 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 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package davmail.exchange;

import davmail.BundleMessage;
import davmail.Settings;
import davmail.exception.DavMailAuthenticationException;
import davmail.exception.DavMailException;
import davmail.exception.HttpNotFoundException;
import davmail.exception.HttpServerErrorException;
import davmail.http.DavGatewayHttpClientFacade;
import davmail.http.DavGatewayOTPPrompt;
import davmail.util.StringUtil;
import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.httpclient.*;
import org.apache.commons.httpclient.methods.ByteArrayRequestEntity;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.methods.PutMethod;
import org.apache.commons.httpclient.params.HttpClientParams;
import org.apache.commons.httpclient.util.URIUtil;
import org.apache.jackrabbit.webdav.DavException;
import org.apache.jackrabbit.webdav.MultiStatus;
import org.apache.jackrabbit.webdav.MultiStatusResponse;
import org.apache.jackrabbit.webdav.client.methods.CopyMethod;
import org.apache.jackrabbit.webdav.client.methods.MoveMethod;
import org.apache.jackrabbit.webdav.client.methods.PropFindMethod;
import org.apache.jackrabbit.webdav.client.methods.PropPatchMethod;
import org.apache.jackrabbit.webdav.property.*;
import org.apache.jackrabbit.webdav.xml.Namespace;
import org.apache.log4j.Logger;
import org.htmlcleaner.CommentToken;
import org.htmlcleaner.HtmlCleaner;
import org.htmlcleaner.TagNode;

import javax.mail.MessagingException;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
import javax.mail.internet.MimePart;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.NoRouteToHostException;
import java.net.URL;
import java.net.UnknownHostException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;

/**
 * Exchange session through Outlook Web Access (DAV)
 */
public class ExchangeSession {
    protected static final Logger LOGGER = Logger.getLogger("davmail.exchange.ExchangeSession");

    /**
     * Reference GMT timezone to format dates
     */
    public static final SimpleTimeZone GMT_TIMEZONE = new SimpleTimeZone(0, "GMT");

    protected static final Set<String> USER_NAME_FIELDS = new HashSet<String>();

    static {
        USER_NAME_FIELDS.add("username");
        USER_NAME_FIELDS.add("txtUserName");
        USER_NAME_FIELDS.add("userid");
        USER_NAME_FIELDS.add("SafeWordUser");
    }

    protected static final Set<String> PASSWORD_FIELDS = new HashSet<String>();

    static {
        PASSWORD_FIELDS.add("password");
        PASSWORD_FIELDS.add("txtUserPass");
        PASSWORD_FIELDS.add("pw");
        PASSWORD_FIELDS.add("basicPassword");
    }

    protected static final Set<String> TOKEN_FIELDS = new HashSet<String>();

    static {
        TOKEN_FIELDS.add("SafeWordPassword");
    }

    protected static final int FREE_BUSY_INTERVAL = 15;

    protected static final Namespace URN_SCHEMAS_HTTPMAIL = Namespace.getNamespace("urn:schemas:httpmail:");
    protected static final Namespace SCHEMAS_EXCHANGE = Namespace.getNamespace("http://schemas.microsoft.com/exchange/");
    protected static final Namespace SCHEMAS_MAPI_PROPTAG = Namespace.getNamespace("http://schemas.microsoft.com/mapi/proptag/");

    protected static final DavPropertyNameSet EVENT_REQUEST_PROPERTIES = new DavPropertyNameSet();

    static {
        EVENT_REQUEST_PROPERTIES.add(DavPropertyName.create("permanenturl", SCHEMAS_EXCHANGE));
        EVENT_REQUEST_PROPERTIES.add(DavPropertyName.GETETAG);
    }

    protected static final DavPropertyNameSet WELL_KNOWN_FOLDERS = new DavPropertyNameSet();

    static {
        WELL_KNOWN_FOLDERS.add(DavPropertyName.create("inbox", URN_SCHEMAS_HTTPMAIL));
        WELL_KNOWN_FOLDERS.add(DavPropertyName.create("deleteditems", URN_SCHEMAS_HTTPMAIL));
        WELL_KNOWN_FOLDERS.add(DavPropertyName.create("sentitems", URN_SCHEMAS_HTTPMAIL));
        WELL_KNOWN_FOLDERS.add(DavPropertyName.create("sendmsg", URN_SCHEMAS_HTTPMAIL));
        WELL_KNOWN_FOLDERS.add(DavPropertyName.create("drafts", URN_SCHEMAS_HTTPMAIL));
        WELL_KNOWN_FOLDERS.add(DavPropertyName.create("calendar", URN_SCHEMAS_HTTPMAIL));
        WELL_KNOWN_FOLDERS.add(DavPropertyName.create("contacts", URN_SCHEMAS_HTTPMAIL));
    }

    protected static final DavPropertyNameSet DISPLAY_NAME = new DavPropertyNameSet();

    static {
        DISPLAY_NAME.add(DavPropertyName.DISPLAYNAME);
    }

    protected static final DavPropertyNameSet FOLDER_PROPERTIES = new DavPropertyNameSet();

    static {
        FOLDER_PROPERTIES.add(DavPropertyName.create("hassubs"));
        FOLDER_PROPERTIES.add(DavPropertyName.create("nosubs"));
        FOLDER_PROPERTIES.add(DavPropertyName.create("unreadcount", URN_SCHEMAS_HTTPMAIL));
        FOLDER_PROPERTIES.add(DavPropertyName.create("contenttag", Namespace.getNamespace("http://schemas.microsoft.com/repl/")));
    }

    protected static final DavPropertyNameSet CONTENT_TAG = new DavPropertyNameSet();

    static {
        CONTENT_TAG.add(DavPropertyName.create("contenttag", Namespace.getNamespace("http://schemas.microsoft.com/repl/")));
    }

    protected static final DavPropertyNameSet RESOURCE_TAG = new DavPropertyNameSet();

    static {
        RESOURCE_TAG.add(DavPropertyName.create("resourcetag", Namespace.getNamespace("http://schemas.microsoft.com/repl/")));
    }

    protected static final DavPropertyName DEFAULT_SCHEDULE_STATE_PROPERTY = DavPropertyName.create("schedule-state", Namespace.getNamespace("CALDAV:"));
    protected DavPropertyName scheduleStateProperty = DEFAULT_SCHEDULE_STATE_PROPERTY;
    protected static final DavPropertyName PR_INTERNET_CONTENT = DavPropertyName.create("x66590102", SCHEMAS_MAPI_PROPTAG);

    /**
     * Various standard mail boxes Urls
     */
    private String inboxUrl;
    private String deleteditemsUrl;
    private String sentitemsUrl;
    private String sendmsgUrl;
    private String draftsUrl;
    private String calendarUrl;
    private String contactsUrl;
    private String publicFolderUrl;

    /**
     * Base user mailboxes path (used to select folder)
     */
    private String mailPath;
    private String email;
    private String alias;
    private final HttpClient httpClient;

    private final String userName;

    private boolean disableGalLookup;
    private static final String YYYY_MM_DD_HH_MM_SS = "yyyy/MM/dd HH:mm:ss";
    private static final String YYYYMMDD_T_HHMMSS_Z = "yyyyMMdd'T'HHmmss'Z'";
    private static final String YYYY_MM_DD_T_HHMMSS_Z = "yyyy-MM-dd'T'HH:mm:ss'Z'";
    private static final String YYYY_MM_DD_T_HHMMSS_SSS_Z = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";

    /**
     * Logon form user name field, default is username.
     */
    private String userNameInput = "username";
    /**
     * Logon form password field, default is password.
     */
    private String passwordInput = "password";

    /**
     * Create an exchange session for the given URL.
     * The session is established for given userName and password
     *
     * @param url      Exchange url
     * @param userName user login name
     * @param password user password
     * @throws IOException on error
     */
    ExchangeSession(String url, String userName, String password) throws IOException {
        this.userName = userName;
        try {
            boolean isBasicAuthentication = isBasicAuthentication(url);

            httpClient = DavGatewayHttpClientFacade.getInstance(url, userName, password);

            // get webmail root url
            // providing credentials
            // manually follow redirect
            HttpMethod method = DavGatewayHttpClientFacade.executeFollowRedirects(httpClient, url);

            if (isBasicAuthentication) {
                int status = method.getStatusCode();

                if (status == HttpStatus.SC_UNAUTHORIZED) {
                    method.releaseConnection();
                    throw new DavMailAuthenticationException("EXCEPTION_AUTHENTICATION_FAILED");
                } else if (status != HttpStatus.SC_OK) {
                    method.releaseConnection();
                    throw DavGatewayHttpClientFacade.buildHttpException(method);
                }
            } else {
                method = formLogin(httpClient, method, userName, password);
            }

            // avoid 401 roundtrips
            httpClient.getParams().setParameter(HttpClientParams.PREEMPTIVE_AUTHENTICATION, true);

            buildMailPath(method);

            // get base http mailbox http urls
            getWellKnownFolders();

        } catch (DavMailAuthenticationException exc) {
            LOGGER.error(exc.getLogMessage());
            throw exc;
        } catch (UnknownHostException exc) {
            BundleMessage message = new BundleMessage("EXCEPTION_CONNECT", exc.getClass().getName(), exc.getMessage());
            ExchangeSession.LOGGER.error(message);
            throw new DavMailException("EXCEPTION_DAVMAIL_CONFIGURATION", message);
        } catch (IOException exc) {
            LOGGER.error(BundleMessage.formatLog("EXCEPTION_EXCHANGE_LOGIN_FAILED", exc));
            throw new DavMailException("EXCEPTION_EXCHANGE_LOGIN_FAILED", exc);
        }
        LOGGER.debug("Session " + this + " created");
    }

    protected String formatSearchDate(Date date) {
        SimpleDateFormat dateFormatter = new SimpleDateFormat(YYYY_MM_DD_HH_MM_SS, Locale.ENGLISH);
        dateFormatter.setTimeZone(GMT_TIMEZONE);
        return dateFormatter.format(date);
    }

    protected SimpleDateFormat getZuluDateFormat() {
        SimpleDateFormat dateFormat = new SimpleDateFormat(YYYYMMDD_T_HHMMSS_Z, Locale.ENGLISH);
        dateFormat.setTimeZone(GMT_TIMEZONE);
        return dateFormat;
    }

    protected SimpleDateFormat getExchangeZuluDateFormat() {
        SimpleDateFormat dateFormat = new SimpleDateFormat(YYYY_MM_DD_T_HHMMSS_Z, Locale.ENGLISH);
        dateFormat.setTimeZone(GMT_TIMEZONE);
        return dateFormat;
    }

    protected SimpleDateFormat getExchangeZuluDateFormatMillisecond() {
        SimpleDateFormat dateFormat = new SimpleDateFormat(YYYY_MM_DD_T_HHMMSS_SSS_Z, Locale.ENGLISH);
        dateFormat.setTimeZone(GMT_TIMEZONE);
        return dateFormat;
    }

    protected Date parseDate(String dateString) throws ParseException {
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMdd");
        dateFormat.setTimeZone(GMT_TIMEZONE);
        return dateFormat.parse(dateString);
    }


    /**
     * Test if the session expired.
     *
     * @return true this session expired
     * @throws NoRouteToHostException on error
     * @throws UnknownHostException   on error
     */
    public boolean isExpired() throws NoRouteToHostException, UnknownHostException {
        boolean isExpired = false;
        try {
            DavGatewayHttpClientFacade.executePropFindMethod(
                    httpClient, URIUtil.encodePath(inboxUrl), 0, DISPLAY_NAME);
        } catch (UnknownHostException exc) {
            throw exc;
        } catch (NoRouteToHostException exc) {
            throw exc;
        } catch (IOException e) {
            isExpired = true;
        }

        return isExpired;
    }

    /**
     * Test authentication mode : form based or basic.
     *
     * @param url exchange base URL
     * @return true if basic authentication detected
     * @throws IOException unable to connect to exchange
     */
    protected boolean isBasicAuthentication(String url) throws IOException {
        return DavGatewayHttpClientFacade.getHttpStatus(url) == HttpStatus.SC_UNAUTHORIZED;
    }

    protected String getAbsoluteUri(HttpMethod method, String path) throws URIException {
        URI uri = method.getURI();
        if (path != null) {
            // reset query string
            uri.setQuery(null);
            if (path.startsWith("/")) {
                // path is absolute, replace method path
                uri.setPath(path);
            } else if (path.startsWith("http://") || path.startsWith("https://")) {
                return path;
            } else {
                // relative path, build new path
                String currentPath = method.getPath();
                int end = currentPath.lastIndexOf('/');
                if (end >= 0) {
                    uri.setPath(currentPath.substring(0, end + 1) + path);
                } else {
                    throw new URIException(uri.getURI());
                }
            }
        }
        return uri.getURI();
    }

    protected String getScriptBasedFormURL(HttpMethod initmethod, String pathQuery) throws URIException {
        URI initmethodURI = initmethod.getURI();
        int queryIndex = pathQuery.indexOf('?');
        if (queryIndex >= 0) {
            if (queryIndex > 0) {
                // update path
                String newPath = pathQuery.substring(0, queryIndex);
                if (newPath.startsWith("/")) {
                    // absolute path
                    initmethodURI.setPath(newPath);
                } else {
                    String currentPath = initmethodURI.getPath();
                    int folderIndex = currentPath.lastIndexOf('/');
                    if (folderIndex >= 0) {
                        // replace relative path
                        initmethodURI.setPath(currentPath.substring(0, folderIndex + 1) + newPath);
                    } else {
                        // should not happen
                        initmethodURI.setPath('/' + newPath);
                    }
                }
            }
            initmethodURI.setQuery(pathQuery.substring(queryIndex + 1));
        }
        return initmethodURI.getURI();
    }

    /**
     * Try to find logon method path from logon form body.
     *
     * @param httpClient httpClient instance
     * @param initmethod form body http method
     * @return logon method
     * @throws IOException on error
     */
    protected PostMethod buildLogonMethod(HttpClient httpClient, HttpMethod initmethod) throws IOException {

        PostMethod logonMethod = null;

        // create an instance of HtmlCleaner
        HtmlCleaner cleaner = new HtmlCleaner();

        try {
            TagNode node = cleaner.clean(initmethod.getResponseBodyAsStream());
            List forms = node.getElementListByName("form", true);
            if (forms.size() == 1) {
                TagNode form = (TagNode) forms.get(0);
                String logonMethodPath = form.getAttributeByName("action");

                logonMethod = new PostMethod(getAbsoluteUri(initmethod, logonMethodPath));

                List inputList = form.getElementListByName("input", true);
                for (Object input : inputList) {
                    String type = ((TagNode) input).getAttributeByName("type");
                    String name = ((TagNode) input).getAttributeByName("name");
                    String value = ((TagNode) input).getAttributeByName("value");
                    if ("hidden".equalsIgnoreCase(type) && name != null && value != null) {
                        logonMethod.addParameter(name, value);
                    }
                    // custom login form
                    if (USER_NAME_FIELDS.contains(name)) {
                        userNameInput = name;
                    } else if (PASSWORD_FIELDS.contains(name)) {
                        passwordInput = name;
                    } else if ("addr".equals(name)) {
                        // this is not a logon form but a redirect form
                        HttpMethod newInitMethod = DavGatewayHttpClientFacade.executeFollowRedirects(httpClient, logonMethod);
                        logonMethod = buildLogonMethod(httpClient, newInitMethod);
                    } else if (TOKEN_FIELDS.contains(name)) {
                        // one time password, ask user
                        logonMethod.addParameter(name, DavGatewayOTPPrompt.getOneTimePassword());
                    }
                }
            } else {
                List frameList = node.getElementListByName("frame", true);
                if (frameList.size() == 1) {
                    String src = ((TagNode) frameList.get(0)).getAttributeByName("src");
                    if (src != null) {
                        LOGGER.debug("Frames detected in form page, try frame content");
                        initmethod.releaseConnection();
                        HttpMethod newInitMethod = DavGatewayHttpClientFacade.executeFollowRedirects(httpClient, src);
                        logonMethod = buildLogonMethod(httpClient, newInitMethod);
                    }
                } else {
                    // another failover for script based logon forms (Exchange 2007)
                    List scriptList = node.getElementListByName("script", true);
                    for (Object script : scriptList) {
                        List contents = ((TagNode) script).getChildren();
                        for (Object content : contents) {
                            if (content instanceof CommentToken) {
                                String scriptValue = ((CommentToken) content).getCommentedContent();
                                String sUrl = StringUtil.getToken(scriptValue, "var a_sUrl = \"", "\"");
                                String sLgn = StringUtil.getToken(scriptValue, "var a_sLgn = \"", "\"");
                                if (sLgn == null) {
                                    sLgn = StringUtil.getToken(scriptValue, "var a_sLgnQS = \"", "\"");
                                }
                                if (sUrl != null && sLgn != null) {
                                    String src = getScriptBasedFormURL(initmethod, sLgn + sUrl);
                                    LOGGER.debug("Detected script based logon, redirect to form at " + src);
                                    HttpMethod newInitMethod = DavGatewayHttpClientFacade.executeFollowRedirects(httpClient, src);
                                    logonMethod = buildLogonMethod(httpClient, newInitMethod);
                                }
                            }
                        }
                    }
                }
            }
        } catch (IOException e) {
            LOGGER.error("Error parsing login form at " + initmethod.getURI());
        } finally {
            initmethod.releaseConnection();
        }

        return logonMethod;
    }

    protected HttpMethod formLogin(HttpClient httpClient, HttpMethod initmethod, String userName, String password) throws IOException {
        LOGGER.debug("Form based authentication detected");

        HttpMethod logonMethod = buildLogonMethod(httpClient, initmethod);
        if (logonMethod == null) {
            throw new DavMailException("EXCEPTION_AUTHENTICATION_FORM_NOT_FOUND", initmethod.getURI());
        }

        // make sure username and password fields are empty
        ((PostMethod) logonMethod).removeParameter(userNameInput);
        ((PostMethod) logonMethod).removeParameter(passwordInput);
        ((PostMethod) logonMethod).removeParameter("trusted");
        ((PostMethod) logonMethod).removeParameter("flags");
        ((PostMethod) logonMethod).addParameter(userNameInput, userName);
        ((PostMethod) logonMethod).addParameter(passwordInput, password);
        ((PostMethod) logonMethod).addParameter("trusted", "4");
        ((PostMethod) logonMethod).addParameter("flags", "4");
        logonMethod = DavGatewayHttpClientFacade.executeFollowRedirects(httpClient, logonMethod);

        // test form based authentication
        checkFormLoginQueryString(logonMethod);

        // workaround for post logon script redirect
        if (!isAuthenticated()) {
            // try to get new method from script based redirection
            logonMethod = buildLogonMethod(httpClient, logonMethod);

            if (logonMethod != null) {
                // if logonMethod is not null, try to follow redirection
                logonMethod = DavGatewayHttpClientFacade.executeFollowRedirects(httpClient, logonMethod);
                checkFormLoginQueryString(logonMethod);
                // also check cookies
                if (!isAuthenticated()) {
                    throwAuthenticationFailed();
                }
            } else {
                // authentication failed
                throwAuthenticationFailed();
            }
        }

        return logonMethod;
    }

    /**
     * Look for session cookies.
     *
     * @return true if session cookies are available
     */
    protected boolean isAuthenticated() {
        boolean authenticated = false;
        for (Cookie cookie : httpClient.getState().getCookies()) {
            // Exchange 2003 cookies
            if (cookie.getName().startsWith("cadata") || "sessionid".equals(cookie.getName())
                    // Exchange 2007 cookie
                    || "UserContext".equals(cookie.getName())) {
                authenticated = true;
                break;
            }
        }
        return authenticated;
    }

    protected void checkFormLoginQueryString(HttpMethod logonMethod) throws DavMailAuthenticationException {
        String queryString = logonMethod.getQueryString();
        if (queryString != null && queryString.contains("reason=2")) {
            logonMethod.releaseConnection();
            throwAuthenticationFailed();
        }
    }

    protected void throwAuthenticationFailed() throws DavMailAuthenticationException {
        if (this.userName != null && this.userName.contains("\\")) {
            throw new DavMailAuthenticationException("EXCEPTION_AUTHENTICATION_FAILED");
        } else {
            throw new DavMailAuthenticationException("EXCEPTION_AUTHENTICATION_FAILED_RETRY");
        }
    }

    static final String BASE_HREF = "<base href=\"";

    protected void buildMailPath(HttpMethod method) throws DavMailAuthenticationException {
        // find base url
        String line;

        // get user mail URL from html body (multi frame)
        BufferedReader mainPageReader = null;
        try {
            mainPageReader = new BufferedReader(new InputStreamReader(method.getResponseBodyAsStream()));
            //noinspection StatementWithEmptyBody
            while ((line = mainPageReader.readLine()) != null && line.toLowerCase().indexOf(BASE_HREF) == -1) {
            }
            if (line != null) {
                int start = line.toLowerCase().indexOf(BASE_HREF) + BASE_HREF.length();
                int end = line.indexOf('\"', start);
                String mailBoxBaseHref = line.substring(start, end);
                URL baseURL = new URL(mailBoxBaseHref);
                mailPath = baseURL.getPath();
                LOGGER.debug("Base href found in body, mailPath is " + mailPath);
                buildEmail(method.getURI().getHost(), method.getPath());
                LOGGER.debug("Current user email is " + email);
            } else {
                // failover for Exchange 2007 : build standard mailbox link with email
                buildEmail(method.getURI().getHost(), method.getPath());
                mailPath = "/exchange/" + email + '/';
                LOGGER.debug("Current user email is " + email + ", mailPath is " + mailPath);
            }
        } catch (IOException e) {
            LOGGER.error("Error parsing main page at " + method.getPath(), e);
        } finally {
            if (mainPageReader != null) {
                try {
                    mainPageReader.close();
                } catch (IOException e) {
                    LOGGER.error("Error parsing main page at " + method.getPath());
                }
            }
            method.releaseConnection();
        }


        if (mailPath == null || email == null) {
            throw new DavMailAuthenticationException("EXCEPTION_AUTHENTICATION_FAILED_PASSWORD_EXPIRED");
        }
    }

    protected String getPropertyIfExists(DavPropertySet properties, String name, Namespace namespace) {
        DavProperty property = properties.get(name, namespace);
        if (property == null) {
            return null;
        } else {
            return (String) property.getValue();
        }
    }

    protected String getPropertyIfExists(DavPropertySet properties, DavPropertyName davPropertyName) {
        DavProperty property = properties.get(davPropertyName);
        if (property == null) {
            return null;
        } else {
            return (String) property.getValue();
        }
    }

    protected int getIntPropertyIfExists(DavPropertySet properties, String name, Namespace namespace) {
        DavProperty property = properties.get(name, namespace);
        if (property == null) {
            return 0;
        } else {
            return Integer.parseInt((String) property.getValue());
        }
    }

    protected long getLongPropertyIfExists(DavPropertySet properties, String name, Namespace namespace) {
        DavProperty property = properties.get(name, namespace);
        if (property == null) {
            return 0;
        } else {
            return Long.parseLong((String) property.getValue());
        }
    }

    protected String getURIPropertyIfExists(DavPropertySet properties, String name, Namespace namespace) throws URIException {
        DavProperty property = properties.get(name, namespace);
        if (property == null) {
            return null;
        } else {
            return URIUtil.decode((String) property.getValue());
        }
    }

    protected void getWellKnownFolders() throws DavMailException {
        // Retrieve well known URLs
        MultiStatusResponse[] responses;
        try {
            responses = DavGatewayHttpClientFacade.executePropFindMethod(
                    httpClient, URIUtil.encodePath(mailPath), 0, WELL_KNOWN_FOLDERS);
            if (responses.length == 0) {
                throw new DavMailException("EXCEPTION_UNABLE_TO_GET_MAIL_FOLDER", mailPath);
            }
            DavPropertySet properties = responses[0].getProperties(HttpStatus.SC_OK);
            inboxUrl = getURIPropertyIfExists(properties, "inbox", URN_SCHEMAS_HTTPMAIL);
            deleteditemsUrl = getURIPropertyIfExists(properties, "deleteditems", URN_SCHEMAS_HTTPMAIL);
            sentitemsUrl = getURIPropertyIfExists(properties, "sentitems", URN_SCHEMAS_HTTPMAIL);
            sendmsgUrl = getURIPropertyIfExists(properties, "sendmsg", URN_SCHEMAS_HTTPMAIL);
            draftsUrl = getURIPropertyIfExists(properties, "drafts", URN_SCHEMAS_HTTPMAIL);
            calendarUrl = getURIPropertyIfExists(properties, "calendar", URN_SCHEMAS_HTTPMAIL);
            contactsUrl = getURIPropertyIfExists(properties, "contacts", URN_SCHEMAS_HTTPMAIL);

            try {
                PropFindMethod propFindMethod = new PropFindMethod("/public", CONTENT_TAG, 0);
                DavGatewayHttpClientFacade.executeMethod(httpClient, propFindMethod);
                publicFolderUrl = propFindMethod.getURI().getURI();
            } catch (IOException e) {
                LOGGER.warn("Public folders not available: " + (e.getMessage() == null ? e : e.getMessage()));
                // default public folder path
                publicFolderUrl = "/public";
            }
            LOGGER.debug("Inbox URL : " + inboxUrl +
                    " Trash URL : " + deleteditemsUrl +
                    " Sent URL : " + sentitemsUrl +
                    " Send URL : " + sendmsgUrl +
                    " Drafts URL : " + draftsUrl +
                    " Calendar URL : " + calendarUrl +
                    " Contacts URL : " + contactsUrl +
                    " Public folder URL : " + publicFolderUrl
            );
        } catch (IOException e) {
            LOGGER.error(e.getMessage());
            throw new DavMailAuthenticationException("EXCEPTION_UNABLE_TO_GET_MAIL_FOLDER", mailPath);
        }
    }

    /**
     * Create message in specified folder.
     * Will overwrite an existing message with same subject in the same folder
     *
     * @param folderPath  Exchange folder path
     * @param messageName message name
     * @param properties  message properties (flags)
     * @param messageBody mail body
     * @throws IOException when unable to create message
     */
    public void createMessage(String folderPath, String messageName, HashMap<String, String> properties, String messageBody) throws IOException {
        String messageUrl = URIUtil.encodePathQuery(getFolderPath(folderPath) + '/' + messageName + ".EML");
        PropPatchMethod patchMethod;
        // create the message first as draft
        if (properties.containsKey("draft")) {
            patchMethod = new PropPatchMethod(messageUrl, buildProperties(properties));
            try {
                // update message with blind carbon copy and other flags
                int statusCode = httpClient.executeMethod(patchMethod);
                if (statusCode != HttpStatus.SC_MULTI_STATUS) {
                    throw new DavMailException("EXCEPTION_UNABLE_TO_CREATE_MESSAGE", messageUrl, statusCode, ' ', patchMethod.getStatusLine());
                }

            } finally {
                patchMethod.releaseConnection();
            }
        }

        PutMethod putmethod = new PutMethod(messageUrl);
        putmethod.setRequestHeader("Translate", "f");
        try {
            // use same encoding as client socket reader
            putmethod.setRequestEntity(new ByteArrayRequestEntity(messageBody.getBytes()));
            int code = httpClient.executeMethod(putmethod);

            if (code != HttpStatus.SC_OK && code != HttpStatus.SC_CREATED) {
                throw new DavMailException("EXCEPTION_UNABLE_TO_CREATE_MESSAGE", messageUrl, code, ' ', putmethod.getStatusLine());
            }
        } finally {
            putmethod.releaseConnection();
        }

        // add bcc and other properties
        if (!properties.isEmpty()) {
            patchMethod = new PropPatchMethod(messageUrl, buildProperties(properties));
            try {
                // update message with blind carbon copy and other flags
                int statusCode = httpClient.executeMethod(patchMethod);
                if (statusCode != HttpStatus.SC_MULTI_STATUS) {
                    throw new DavMailException("EXCEPTION_UNABLE_TO_PATCH_MESSAGE", messageUrl, statusCode, ' ', patchMethod.getStatusLine());
                }

            } finally {
                patchMethod.releaseConnection();
            }
        }
    }

    protected Message buildMessage(MultiStatusResponse responseEntity) throws URIException {
        Message message = new Message();
        message.messageUrl = URIUtil.decode(responseEntity.getHref());
        DavPropertySet properties = responseEntity.getProperties(HttpStatus.SC_OK);

        message.permanentUrl = getPropertyIfExists(properties, "permanenturl", SCHEMAS_EXCHANGE);
        message.size = getIntPropertyIfExists(properties, "x0e080003", SCHEMAS_MAPI_PROPTAG);
        message.uid = getPropertyIfExists(properties, "uid", Namespace.getNamespace("DAV:"));
        message.imapUid = getLongPropertyIfExists(properties, "x0e230003", SCHEMAS_MAPI_PROPTAG);
        message.read = "1".equals(getPropertyIfExists(properties, "read", URN_SCHEMAS_HTTPMAIL));
        message.junk = "1".equals(getPropertyIfExists(properties, "x10830003", SCHEMAS_MAPI_PROPTAG));
        message.flagged = "2".equals(getPropertyIfExists(properties, "x10900003", SCHEMAS_MAPI_PROPTAG));
        message.draft = "9".equals(getPropertyIfExists(properties, "x0E070003", SCHEMAS_MAPI_PROPTAG));
        String x10810003 = getPropertyIfExists(properties, "x10810003", SCHEMAS_MAPI_PROPTAG);
        message.answered = "102".equals(x10810003) || "103".equals(x10810003);
        message.forwarded = "104".equals(x10810003);
        message.date = getPropertyIfExists(properties, "date", Namespace.getNamespace("urn:schemas:mailheader:"));
        message.deleted = "1".equals(getPropertyIfExists(properties, "deleted", Namespace.getNamespace("")));
        message.messageId = getPropertyIfExists(properties, "message-id", Namespace.getNamespace("urn:schemas:mailheader:"));
        if (message.messageId != null && message.messageId.startsWith("<") && message.messageId.endsWith(">")) {
            message.messageId = message.messageId.substring(1, message.messageId.length() - 1);
        }

        if (LOGGER.isDebugEnabled()) {
            StringBuilder buffer = new StringBuilder();
            buffer.append("Message");
            if (message.imapUid != 0) {
                buffer.append(" IMAP uid: ").append(message.imapUid);
            }
            if (message.uid != null) {
                buffer.append(" uid: ").append(message.uid);
            }
            buffer.append(" href: ").append(responseEntity.getHref()).append(" permanenturl:").append(message.permanentUrl);
            LOGGER.debug(buffer.toString());
        }
        return message;
    }

    protected List<DavProperty> buildProperties(Map<String, String> properties) {
        ArrayList<DavProperty> list = new ArrayList<DavProperty>();
        for (Map.Entry<String, String> entry : properties.entrySet()) {
            if ("read".equals(entry.getKey())) {
                list.add(new DefaultDavProperty(DavPropertyName.create("read", URN_SCHEMAS_HTTPMAIL), entry.getValue()));
            } else if ("junk".equals(entry.getKey())) {
                list.add(new DefaultDavProperty(DavPropertyName.create("x10830003", SCHEMAS_MAPI_PROPTAG), entry.getValue()));
            } else if ("flagged".equals(entry.getKey())) {
                list.add(new DefaultDavProperty(DavPropertyName.create("x10900003", SCHEMAS_MAPI_PROPTAG), entry.getValue()));
            } else if ("answered".equals(entry.getKey())) {
                list.add(new DefaultDavProperty(DavPropertyName.create("x10810003", SCHEMAS_MAPI_PROPTAG), entry.getValue()));
                if ("102".equals(entry.getValue())) {
                    list.add(new DefaultDavProperty(DavPropertyName.create("x10800003", SCHEMAS_MAPI_PROPTAG), "261"));
                }
            } else if ("forwarded".equals(entry.getKey())) {
                list.add(new DefaultDavProperty(DavPropertyName.create("x10810003", SCHEMAS_MAPI_PROPTAG), entry.getValue()));
                if ("104".equals(entry.getValue())) {
                    list.add(new DefaultDavProperty(DavPropertyName.create("x10800003", SCHEMAS_MAPI_PROPTAG), "262"));
                }
            } else if ("bcc".equals(entry.getKey())) {
                list.add(new DefaultDavProperty(DavPropertyName.create("bcc", Namespace.getNamespace("urn:schemas:mailheader:")), entry.getValue()));
            } else if ("draft".equals(entry.getKey())) {
                list.add(new DefaultDavProperty(DavPropertyName.create("x0E070003", SCHEMAS_MAPI_PROPTAG), entry.getValue()));
            } else if ("deleted".equals(entry.getKey())) {
                list.add(new DefaultDavProperty(DavPropertyName.create("_x0030_x8570", Namespace.getNamespace("http://schemas.microsoft.com/mapi/id/{00062008-0000-0000-C000-000000000046}/")), entry.getValue()));
            } else if ("datereceived".equals(entry.getKey())) {
                list.add(new DefaultDavProperty(DavPropertyName.create("datereceived", URN_SCHEMAS_HTTPMAIL), entry.getValue()));
            }
        }
        return list;
    }

    /**
     * Update given properties on message.
     *
     * @param message    Exchange message
     * @param properties Webdav properties map
     * @throws IOException on error
     */
    public void updateMessage(Message message, Map<String, String> properties) throws IOException {
        PropPatchMethod patchMethod = new PropPatchMethod(message.permanentUrl, buildProperties(properties)) {
            @Override
            protected void processResponseBody(HttpState httpState, HttpConnection httpConnection) {
                // ignore response body, sometimes invalid with exchange mapi properties
            }
        };
        try {
            int statusCode = httpClient.executeMethod(patchMethod);
            if (statusCode != HttpStatus.SC_MULTI_STATUS) {
                throw new DavMailException("EXCEPTION_UNABLE_TO_UPDATE_MESSAGE");
            }

        } finally {
            patchMethod.releaseConnection();
        }
    }

    /**
     * Return folder message list with id and size only (for POP3 listener).
     *
     * @param folderName Exchange folder name
     * @return folder message list
     * @throws IOException on error
     */
    public MessageList getAllMessageUidAndSize(String folderName) throws IOException {
        return searchMessages(folderName, "\"DAV:uid\", \"http://schemas.microsoft.com/mapi/proptag/x0e080003\"", "");
    }

    /**
     * Search folder for messages matching conditions, with attributes needed by IMAP listener.
     *
     * @param folderName Exchange folder name
     * @param conditions conditions string in Exchange SQL syntax
     * @return message list
     * @throws IOException on error
     */
    public MessageList searchMessages(String folderName, String conditions) throws IOException {
        return searchMessages(folderName, "\"DAV:uid\", \"http://schemas.microsoft.com/mapi/proptag/x0e080003\"" +
                "                ,\"http://schemas.microsoft.com/mapi/proptag/x0e230003\"" +
                "                ,\"http://schemas.microsoft.com/mapi/proptag/x10830003\", \"http://schemas.microsoft.com/mapi/proptag/x10900003\"" +
                "                ,\"http://schemas.microsoft.com/mapi/proptag/x0E070003\", \"http://schemas.microsoft.com/mapi/proptag/x10810003\"" +
                "                ,\"urn:schemas:mailheader:message-id\", \"urn:schemas:httpmail:read\" " +
                "                ,\"http://schemas.microsoft.com/mapi/id/{00062008-0000-0000-C000-000000000046}/0x8570\" as deleted, \"urn:schemas:mailheader:date\"", conditions);
    }

    /**
     * Search folder for messages matching conditions, with given attributes.
     *
     * @param folderName Exchange folder name
     * @param attributes requested Webdav attributes
     * @param conditions conditions string in Exchange SQL syntax
     * @return message list
     * @throws IOException on error
     */
    public MessageList searchMessages(String folderName, String attributes, String conditions) throws IOException {
        String folderUrl = getFolderPath(folderName);
        MessageList messages = new MessageList();
        StringBuilder searchRequest = new StringBuilder();
        searchRequest.append("Select \"http://schemas.microsoft.com/exchange/permanenturl\"");
        if (attributes != null && attributes.length() > 0) {
            searchRequest.append(',').append(attributes);
        }
        searchRequest.append("                FROM Scope('SHALLOW TRAVERSAL OF \"").append(folderUrl).append("\"')\n")
                .append("                WHERE \"DAV:ishidden\" = False AND \"DAV:isfolder\" = False\n");
        if (conditions != null) {
            searchRequest.append(conditions);
        }
        searchRequest.append("       ORDER BY \"urn:schemas:httpmail:date\" ASC");
        MultiStatusResponse[] responses = DavGatewayHttpClientFacade.executeSearchMethod(
                httpClient, URIUtil.encodePath(folderUrl), searchRequest.toString());

        for (MultiStatusResponse response : responses) {
            Message message = buildMessage(response);
            messages.add(message);
        }
        Collections.sort(messages);
        return messages;
    }

    /**
     * Search folders under given folder.
     *
     * @param folderName Exchange folder name
     * @param recursive  deep search if true
     * @return list of folders
     * @throws IOException on error
     */
    public List<Folder> getSubFolders(String folderName, boolean recursive) throws IOException {
        return getSubFolders(folderName, "(\"DAV:contentclass\"='urn:content-classes:mailfolder' OR \"DAV:contentclass\"='urn:content-classes:folder')", recursive);
    }

    /**
     * Search calendar folders under given folder.
     *
     * @param folderName Exchange folder name
     * @param recursive  deep search if true
     * @return list of folders
     * @throws IOException on error
     */
    public List<Folder> getSubCalendarFolders(String folderName, boolean recursive) throws IOException {
        return getSubFolders(folderName, "\"DAV:contentclass\"='urn:content-classes:calendarfolder'", recursive);
    }

    /**
     * Search folders under given folder matching filter.
     *
     * @param folderName Exchange folder name
     * @param filter     search filter
     * @param recursive  deep search if true
     * @return list of folders
     * @throws IOException on error
     */
    public List<Folder> getSubFolders(String folderName, String filter, boolean recursive) throws IOException {
        String mode = recursive ? "DEEP" : "SHALLOW";
        List<Folder> folders = new ArrayList<Folder>();
        StringBuilder searchRequest = new StringBuilder();
        searchRequest.append("Select \"DAV:nosubs\", \"DAV:hassubs\", \"DAV:hassubs\"," +
                "\"urn:schemas:httpmail:unreadcount\" FROM Scope('").append(mode).append(" TRAVERSAL OF \"").append(getFolderPath(folderName)).append("\"')\n" +
                " WHERE \"DAV:ishidden\" = False AND \"DAV:isfolder\" = True \n");
        if (filter != null && filter.length() > 0) {
            searchRequest.append("                      AND ").append(filter);
        }
        MultiStatusResponse[] responses = DavGatewayHttpClientFacade.executeSearchMethod(
                httpClient, URIUtil.encodePath(getFolderPath(folderName)), searchRequest.toString());

        for (MultiStatusResponse response : responses) {
            folders.add(buildFolder(response));
        }
        return folders;
    }

    protected Folder buildFolder(MultiStatusResponse entity) throws IOException {
        String href = URIUtil.decode(entity.getHref());
        Folder folder = new Folder();
        DavPropertySet properties = entity.getProperties(HttpStatus.SC_OK);
        folder.hasChildren = "1".equals(getPropertyIfExists(properties, "hassubs", Namespace.getNamespace("DAV:")));
        folder.noInferiors = "1".equals(getPropertyIfExists(properties, "nosubs", Namespace.getNamespace("DAV:")));
        folder.unreadCount = getIntPropertyIfExists(properties, "unreadcount", URN_SCHEMAS_HTTPMAIL);
        folder.contenttag = getPropertyIfExists(properties, "contenttag", Namespace.getNamespace("http://schemas.microsoft.com/repl/"));

        // replace well known folder names
        if (href.startsWith(inboxUrl)) {
            folder.folderPath = href.replaceFirst(inboxUrl, "INBOX");
        } else if (href.startsWith(sentitemsUrl)) {
            folder.folderPath = href.replaceFirst(sentitemsUrl, "Sent");
        } else if (href.startsWith(draftsUrl)) {
            folder.folderPath = href.replaceFirst(draftsUrl, "Drafts");
        } else if (href.startsWith(deleteditemsUrl)) {
            folder.folderPath = href.replaceFirst(deleteditemsUrl, "Trash");
        } else {
            int index = href.indexOf(mailPath.substring(0, mailPath.length() - 1));
            if (index >= 0) {
                if (index + mailPath.length() > href.length()) {
                    folder.folderPath = "";
                } else {
                    folder.folderPath = href.substring(index + mailPath.length());
                }
            } else {
                try {
                    URI folderURI = new URI(href, false);
                    folder.folderPath = folderURI.getPath();
                } catch (URIException e) {
                    throw new DavMailException("EXCEPTION_INVALID_FOLDER_URL", href);
                }
            }
        }
        if (folder.folderPath.endsWith("/")) {
            folder.folderPath = folder.folderPath.substring(0, folder.folderPath.length() - 1);
        }
        return folder;
    }

    /**
     * Delete oldest messages in trash.
     * keepDelay is the number of days to keep messages in trash before delete
     *
     * @throws IOException when unable to purge messages
     */
    public void purgeOldestTrashAndSentMessages() throws IOException {
        int keepDelay = Settings.getIntProperty("davmail.keepDelay");
        if (keepDelay != 0) {
            purgeOldestFolderMessages(deleteditemsUrl, keepDelay);
        }
        // this is a new feature, default is : do nothing
        int sentKeepDelay = Settings.getIntProperty("davmail.sentKeepDelay");
        if (sentKeepDelay != 0) {
            purgeOldestFolderMessages(sentitemsUrl, sentKeepDelay);
        }
    }

    protected void purgeOldestFolderMessages(String folderUrl, int keepDelay) throws IOException {
        Calendar cal = Calendar.getInstance();
        cal.add(Calendar.DAY_OF_MONTH, -keepDelay);
        LOGGER.debug("Delete messages in " + folderUrl + " since " + cal.getTime());

        String searchRequest = "Select \"DAV:uid\"" +
                "                FROM Scope('SHALLOW TRAVERSAL OF \"" + folderUrl + "\"')\n" +
                "                WHERE \"DAV:isfolder\" = False\n" +
                "                   AND \"DAV:getlastmodified\" < '" + formatSearchDate(cal.getTime()) + "'\n";
        MultiStatusResponse[] responses = DavGatewayHttpClientFacade.executeSearchMethod(
                httpClient, URIUtil.encodePath(folderUrl), searchRequest);

        for (MultiStatusResponse response : responses) {
            String messageUrl = URIUtil.decode(response.getHref());

            LOGGER.debug("Delete " + messageUrl);
            DavGatewayHttpClientFacade.executeDeleteMethod(httpClient, URIUtil.encodePath(messageUrl));
        }
    }

    /**
     * Send message in reader to recipients.
     * Detect visible recipients in message body to determine bcc recipients
     *
     * @param recipients recipients list
     * @param reader     message stream
     * @throws IOException on error
     */
    public void sendMessage(List<String> recipients, BufferedReader reader) throws IOException {
        String line = reader.readLine();
        StringBuilder mailBuffer = new StringBuilder();
        StringBuilder recipientBuffer = new StringBuilder();
        boolean inHeader = true;
        boolean inRecipientHeader = false;
        while (!".".equals(line)) {
            mailBuffer.append(line).append((char) 13).append((char) 10);
            line = reader.readLine();
            // Exchange 2007 : skip From: header
            if ((inHeader && line.length() >= 5)) {
                String prefix = line.substring(0, 5).toLowerCase();
                if ("from:".equals(prefix)) {
                    line = reader.readLine();
                }
            }

            if (inHeader && line.length() == 0) {
                inHeader = false;
            }

            inRecipientHeader = inRecipientHeader && line.startsWith(" ");

            if ((inHeader && line.length() >= 3) || inRecipientHeader) {
                String prefix = line.substring(0, 3).toLowerCase();
                if ("to:".equals(prefix) || "cc:".equals(prefix) || inRecipientHeader) {
                    inRecipientHeader = true;
                    recipientBuffer.append(line);
                }
            }
        }
        // remove visible recipients from list
        List<String> visibleRecipients = new ArrayList<String>();
        for (String recipient : recipients) {
            if (recipientBuffer.indexOf(recipient) >= 0) {
                visibleRecipients.add(recipient);
            }
        }
        recipients.removeAll(visibleRecipients);

        StringBuilder bccBuffer = new StringBuilder();
        for (String recipient : recipients) {
            if (bccBuffer.length() > 0) {
                bccBuffer.append(',');
            }
            bccBuffer.append('<');
            bccBuffer.append(recipient);
            bccBuffer.append('>');
        }

        String bcc = bccBuffer.toString();
        HashMap<String, String> properties = new HashMap<String, String>();
        if (bcc.length() > 0) {
            properties.put("bcc", bcc);
        }

        String messageName = UUID.randomUUID().toString();

        createMessage("Drafts", messageName, properties, mailBuffer.toString());

        String tempUrl = draftsUrl + '/' + messageName + ".EML";
        MoveMethod method = new MoveMethod(URIUtil.encodePath(tempUrl), URIUtil.encodePath(sendmsgUrl), true);
        int status = DavGatewayHttpClientFacade.executeHttpMethod(httpClient, method);
        if (status != HttpStatus.SC_OK) {
            throw DavGatewayHttpClientFacade.buildHttpException(method);
        }
    }

    /**
     * Convert logical or relative folder path to absolute folder path.
     *
     * @param folderName folder name
     * @return folder path
     */
    public String getFolderPath(String folderName) {
        String folderPath;
        if (folderName.startsWith("INBOX")) {
            folderPath = folderName.replaceFirst("INBOX", inboxUrl);
        } else if (folderName.startsWith("Trash")) {
            folderPath = folderName.replaceFirst("Trash", deleteditemsUrl);
        } else if (folderName.startsWith("Drafts")) {
            folderPath = folderName.replaceFirst("Drafts", draftsUrl);
        } else if (folderName.startsWith("Sent")) {
            folderPath = folderName.replaceFirst("Sent", sentitemsUrl);
        } else if (folderName.startsWith("calendar")) {
            folderPath = folderName.replaceFirst("calendar", calendarUrl);
        } else if (folderName.startsWith("public")) {
            folderPath = publicFolderUrl + folderName.substring("public".length());
            // absolute folder path
        } else if (folderName.startsWith("/")) {
            folderPath = folderName;
        } else {
            folderPath = mailPath + folderName;
        }
        return folderPath;
    }

    /**
     * Get folder object.
     * Folder name can be logical names INBOX, Drafts, Trash or calendar,
     * or a path relative to user base folder or absolute path.
     *
     * @param folderName folder name
     * @return Folder object
     * @throws IOException on error
     */
    public Folder getFolder(String folderName) throws IOException {
        MultiStatusResponse[] responses = DavGatewayHttpClientFacade.executePropFindMethod(
                httpClient, URIUtil.encodePath(getFolderPath(folderName)), 0, FOLDER_PROPERTIES);
        Folder folder = null;
        if (responses.length > 0) {
            folder = buildFolder(responses[0]);
            folder.folderName = folderName;
        }
        return folder;
    }

    /**
     * Check folder ctag and reload messages as needed.
     *
     * @param currentFolder current folder
     * @return true if folder changed
     * @throws IOException on error
     */
    public boolean refreshFolder(Folder currentFolder) throws IOException {
        Folder newFolder = getFolder(currentFolder.folderName);
        if (currentFolder.contenttag == null || !currentFolder.contenttag.equals(newFolder.contenttag)) {
            if (LOGGER.isDebugEnabled()) {
                LOGGER.debug("Contenttag changed on " + currentFolder.folderName + ' '
                        + currentFolder.contenttag + " => " + newFolder.contenttag + ", reloading messages");
            }
            currentFolder.hasChildren = newFolder.hasChildren;
            currentFolder.noInferiors = newFolder.noInferiors;
            currentFolder.unreadCount = newFolder.unreadCount;
            currentFolder.contenttag = newFolder.contenttag;
            currentFolder.loadMessages();
            return true;
        } else {
            return false;
        }
    }

    /**
     * Create Exchange message folder.
     *
     * @param folderName logical folder name
     * @throws IOException on error
     */
    public void createMessageFolder(String folderName) throws IOException {
        createFolder(folderName, "IPF.Note");
    }

    /**
     * Create Exchange calendar folder.
     *
     * @param folderName logical folder name
     * @throws IOException on error
     */
    public void createCalendarFolder(String folderName) throws IOException {
        createFolder(folderName, "IPF.Appointment");
    }

    /**
     * Create Exchange folder with given folder class.
     *
     * @param folderName  logical folder name
     * @param folderClass folder class
     * @throws IOException on error
     */
    public void createFolder(String folderName, String folderClass) throws IOException {
        String folderPath = getFolderPath(folderName);
        ArrayList<DavProperty> list = new ArrayList<DavProperty>();
        list.add(new DefaultDavProperty(DavPropertyName.create("outlookfolderclass", Namespace.getNamespace("http://schemas.microsoft.com/exchange/")), folderClass));
        // standard MkColMethod does not take properties, override PropPatchMethod instead
        PropPatchMethod method = new PropPatchMethod(URIUtil.encodePath(folderPath), list) {
            @Override
            public String getName() {
                return "MKCOL";
            }
        };
        int status = DavGatewayHttpClientFacade.executeHttpMethod(httpClient, method);
        // ok or alredy exists
        if (status != HttpStatus.SC_MULTI_STATUS && status != HttpStatus.SC_METHOD_NOT_ALLOWED) {
            throw DavGatewayHttpClientFacade.buildHttpException(method);
        }
    }

    /**
     * Delete Exchange folder.
     *
     * @param folderName logical folder name
     * @throws IOException on error
     */
    public void deleteFolder(String folderName) throws IOException {
        DavGatewayHttpClientFacade.executeDeleteMethod(httpClient, URIUtil.encodePath(getFolderPath(folderName)));
    }

    /**
     * Copy message to target folder
     *
     * @param message      Exchange message
     * @param targetFolder target folder
     * @throws IOException on error
     */
    public void copyMessage(Message message, String targetFolder) throws IOException {
        String targetPath = URIUtil.encodePath(getFolderPath(targetFolder)) + '/' + UUID.randomUUID().toString();
        CopyMethod method = new CopyMethod(message.permanentUrl, targetPath, false);
        // allow rename if a message with the same name exists
        method.addRequestHeader("Allow-Rename", "t");
        try {
            int statusCode = httpClient.executeMethod(method);
            if (statusCode == HttpStatus.SC_PRECONDITION_FAILED) {
                throw new DavMailException("EXCEPTION_UNABLE_TO_COPY_MESSAGE");
            } else if (statusCode != HttpStatus.SC_CREATED) {
                throw DavGatewayHttpClientFacade.buildHttpException(method);
            }
        } finally {
            method.releaseConnection();
        }
    }

    /**
     * Move folder to target name.
     *
     * @param folderName current folder name/path
     * @param targetName target folder name/path
     * @throws IOException on error
     */
    public void moveFolder(String folderName, String targetName) throws IOException {
        String folderPath = getFolderPath(folderName);
        String targetPath = getFolderPath(targetName);
        MoveMethod method = new MoveMethod(URIUtil.encodePath(folderPath), URIUtil.encodePath(targetPath), false);
        try {
            int statusCode = httpClient.executeMethod(method);
            if (statusCode == HttpStatus.SC_PRECONDITION_FAILED) {
                throw new DavMailException("EXCEPTION_UNABLE_TO_MOVE_FOLDER");
            } else if (statusCode != HttpStatus.SC_CREATED) {
                throw DavGatewayHttpClientFacade.buildHttpException(method);
            }
        } finally {
            method.releaseConnection();
        }
    }

    protected void moveToTrash(String encodedMessageUrl) throws IOException {
        String destination = URIUtil.encodePath(deleteditemsUrl) + '/' + UUID.randomUUID().toString();
        LOGGER.debug("Deleting : " + encodedMessageUrl + " to " + destination);
        MoveMethod method = new MoveMethod(encodedMessageUrl, destination, false);
        method.addRequestHeader("Allow-rename", "t");

        int status = DavGatewayHttpClientFacade.executeHttpMethod(httpClient, method);
        // do not throw error if already deleted
        if (status != HttpStatus.SC_CREATED && status != HttpStatus.SC_NOT_FOUND) {
            throw DavGatewayHttpClientFacade.buildHttpException(method);
        }
        if (method.getResponseHeader("Location") != null) {
            destination = method.getResponseHeader("Location").getValue();
        }

        LOGGER.debug("Deleted to :" + destination);
    }

    /**
     * Exchange folder with IMAP properties
     */
    public class Folder {
        /**
         * Logical (IMAP) folder path.
         */
        public String folderPath;
        /**
         * Folder unread message count.
         */
        public int unreadCount;
        /**
         * true if folder has subfolders (DAV:hassubs).
         */
        public boolean hasChildren;
        /**
         * true if folder has no subfolders (DAV:nosubs).
         */
        public boolean noInferiors;
        /**
         * Requested folder name
         */
        public String folderName;
        /**
         * Folder content tag (to detect folder content changes).
         */
        public String contenttag;
        /**
         * Folder message list, empty before loadMessages call.
         */
        public ExchangeSession.MessageList messages;

        /**
         * Get IMAP folder flags.
         *
         * @return folder flags in IMAP format
         */
        public String getFlags() {
            if (noInferiors) {
                return "\\NoInferiors";
            } else if (hasChildren) {
                return "\\HasChildren";
            } else {
                return "\\HasNoChildren";
            }
        }

        /**
         * Load folder messages.
         *
         * @throws IOException on error
         */
        public void loadMessages() throws IOException {
            messages = searchMessages(folderPath, "");
        }

        /**
         * Folder message count.
         *
         * @return message count
         */
        public int count() {
            return messages.size();
        }

        /**
         * Compute IMAP uidnext.
         *
         * @return max(messageuids)+1
         */
        public long getUidNext() {
            return messages.get(messages.size() - 1).getImapUid() + 1;
        }

        /**
         * Get message uid at index.
         *
         * @param index message index
         * @return message uid
         */
        public long getImapUid(int index) {
            return messages.get(index).getImapUid();
        }

        /**
         * Get message at index.
         *
         * @param index message index
         * @return message
         */
        public Message get(int index) {
            return messages.get(index);
        }
    }

    /**
     * Exchange message.
     */
    public class Message implements Comparable<Message> {
        protected String messageUrl;

        protected String permanentUrl;
        /**
         * Message uid.
         */
        protected String uid;
        /**
         * Message IMAP uid, unique in folder (x0e230003).
         */
        protected long imapUid;
        /**
         * MAPI message size.
         */
        public int size;
        /**
         * Mail header message-id.
         */
        protected String messageId;
        /**
         * Message date (urn:schemas:mailheader:date).
         */
        public String date;

        /**
         * Message flag: read.
         */
        public boolean read;
        /**
         * Message flag: deleted.
         */
        public boolean deleted;
        /**
         * Message flag: junk.
         */
        public boolean junk;
        /**
         * Message flag: flagged.
         */
        public boolean flagged;
        /**
         * Message flag: draft.
         */
        public boolean draft;
        /**
         * Message flag: answered.
         */
        public boolean answered;
        /**
         * Message flag: fowarded.
         */
        public boolean forwarded;

        /**
         * Message content parsed in a MIME message.
         */
        protected MimeMessage mimeMessage;

        /**
         * IMAP uid , unique in folder (x0e230003)
         *
         * @return IMAP uid
         */
        public long getImapUid() {
            return imapUid;
        }

        /**
         * Exchange uid.
         *
         * @return uid
         */
        public String getUid() {
            return uid;
        }

        /**
         * Return permanent message url.
         *
         * @return permanent message url
         * @throws URIException on error
         */
        public String getPermanentUrl() throws URIException {
            return permanentUrl;
        }

        /**
         * Return message flags in IMAP format.
         *
         * @return IMAP flags
         */
        public String getImapFlags() {
            StringBuilder buffer = new StringBuilder();
            if (read) {
                buffer.append("\\Seen ");
            }
            if (deleted) {
                buffer.append("\\Deleted ");
            }
            if (flagged) {
                buffer.append("\\Flagged ");
            }
            if (junk) {
                buffer.append("Junk ");
            }
            if (draft) {
                buffer.append("\\Draft ");
            }
            if (answered) {
                buffer.append("\\Answered ");
            }
            if (forwarded) {
                buffer.append("$Forwarded ");
            }
            return buffer.toString().trim();
        }

        /**
         * Write MIME message to os
         *
         * @param os output stream
         * @throws IOException on error
         */
        public void write(OutputStream os) throws IOException {
            try {
                write(os, messageUrl);
            } catch (HttpNotFoundException e) {
                LOGGER.debug("Message not found at: " + messageUrl + ", retrying with permanenturl");
                write(os, permanentUrl);
            }
        }

        protected void write(OutputStream os, String url) throws IOException {
            GetMethod method = new GetMethod(URIUtil.encodePath(url));
            method.setRequestHeader("Content-Type", "text/xml; charset=utf-8");
            method.setRequestHeader("Translate", "f");
            BufferedReader reader = null;
            try {
                DavGatewayHttpClientFacade.executeGetMethod(httpClient, method, false);

                reader = new BufferedReader(new InputStreamReader(method.getResponseBodyAsStream()));
                OutputStreamWriter isoWriter = new OutputStreamWriter(os);
                String line;
                while ((line = reader.readLine()) != null) {
                    if (".".equals(line)) {
                        line = "..";
                        // patch text/calendar to include utf-8 encoding
                    } else if ("Content-Type: text/calendar;".equals(line)) {
                        StringBuilder headerBuffer = new StringBuilder();
                        headerBuffer.append(line);
                        while ((line = reader.readLine()) != null && line.startsWith("\t")) {
                            headerBuffer.append((char) 13);
                            headerBuffer.append((char) 10);
                            headerBuffer.append(line);
                        }
                        if (headerBuffer.indexOf("charset") < 0) {
                            headerBuffer.append(";charset=utf-8");
                        }
                        headerBuffer.append((char) 13);
                        headerBuffer.append((char) 10);
                        headerBuffer.append(line);
                        line = headerBuffer.toString();
                    }
                    isoWriter.write(line);
                    isoWriter.write((char) 13);
                    isoWriter.write((char) 10);
                }
                isoWriter.flush();
            } catch (HttpServerErrorException e) {
                LOGGER.warn("Unable to retrieve message at: " + messageUrl);
                throw e;
            } finally {
                if (reader != null) {
                    try {
                        reader.close();
                    } catch (IOException e) {
                        LOGGER.warn("Error closing message input stream", e);
                    }
                }
                method.releaseConnection();
            }
        }

        /**
         * Load message content in a Mime message
         *
         * @return mime message
         * @throws IOException        on error
         * @throws MessagingException on error
         */
        public MimeMessage getMimeMessage() throws IOException, MessagingException {
            if (mimeMessage == null) {
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                write(baos);
                mimeMessage = new MimeMessage(null, new ByteArrayInputStream(baos.toByteArray()));
            }
            return mimeMessage;
        }

        /**
         * Drop mime message to avoid keeping message content in memory.
         */
        public void dropMimeMessage() {
            mimeMessage = null;
        }

        /**
         * Delete message.
         *
         * @throws IOException on error
         */
        public void delete() throws IOException {
            DavGatewayHttpClientFacade.executeDeleteMethod(httpClient, permanentUrl);
        }

        /**
         * Move message to trash, mark message read.
         *
         * @throws IOException on error
         */
        public void moveToTrash() throws IOException {
            // mark message as read
            HashMap<String, String> properties = new HashMap<String, String>();
            properties.put("read", "1");
            updateMessage(this, properties);

            ExchangeSession.this.moveToTrash(permanentUrl);
        }

        /**
         * Comparator to sort messages by IMAP uid
         *
         * @param message other message
         * @return imapUid comparison result
         */
        public int compareTo(Message message) {
            long compareValue = (imapUid - message.imapUid);
            if (compareValue > 0) {
                return 1;
            } else if (compareValue < 0) {
                return -1;
            } else {
                return 0;
            }
        }

        /**
         * Override equals, compare IMAP uids
         *
         * @param message other message
         * @return true if IMAP uids are equal
         */
        @Override
        public boolean equals(Object message) {
            return message instanceof Message && imapUid == ((Message) message).imapUid;
        }

        /**
         * Override hashCode, return imapUid hashcode.
         *
         * @return imapUid hashcode
         */
        @Override
        public int hashCode() {
            return (int) (imapUid ^ (imapUid >>> 32));
        }
    }

    /**
     * Message list
     */
    public static class MessageList extends ArrayList<Message> {
    }

    /**
     * Calendar event object
     */
    public class Event {
        protected String href;
        protected String permanentUrl;
        protected String etag;
        protected String contentClass;
        protected String noneMatch;
        /**
         * ICS content
         */
        protected String icsBody;

        protected boolean isCalendarContentType(String contentType) {
            return contentType.startsWith("text/calendar") || contentType.startsWith("application/ics");
        }

        protected MimePart getCalendarMimePart(MimeMultipart multiPart) throws IOException, MessagingException {
            MimePart bodyPart = null;
            for (int i = 0; i < multiPart.getCount(); i++) {
                String contentType = multiPart.getBodyPart(i).getContentType();
                if (isCalendarContentType(contentType)) {
                    bodyPart = (MimePart) multiPart.getBodyPart(i);
                    break;
                } else if (contentType.startsWith("multipart")) {
                    Object content = multiPart.getBodyPart(i).getContent();
                    if (content instanceof MimeMultipart) {
                        bodyPart = getCalendarMimePart((MimeMultipart) content);
                    }
                }
            }

            return bodyPart;
        }

        /**
         * Load ICS content from MIME message input stream
         *
         * @param mimeInputStream mime message input stream
         * @return mime message ics attachment body
         * @throws IOException        on error
         * @throws MessagingException on error
         */
        protected String getICS(InputStream mimeInputStream) throws IOException, MessagingException {
            String result;
            MimeMessage mimeMessage = new MimeMessage(null, mimeInputStream);
            Object mimeBody = mimeMessage.getContent();
            MimePart bodyPart = null;
            if (mimeBody instanceof MimeMultipart) {
                bodyPart = getCalendarMimePart((MimeMultipart) mimeBody);
            } else if (isCalendarContentType(mimeMessage.getContentType())) {
                // no multipart, single body
                bodyPart = mimeMessage;
            }

            if (bodyPart != null) {
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                bodyPart.getDataHandler().writeTo(baos);
                baos.close();
                result = fixICS(new String(baos.toByteArray(), "UTF-8"), true);
            } else {
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                mimeMessage.getDataHandler().writeTo(baos);
                baos.close();
                throw new DavMailException("EXCEPTION_INVALID_MESSAGE_CONTENT", new String(baos.toByteArray(), "UTF-8"));
            }
            return result;
        }


        protected String getICSFromInternetContentProperty() throws IOException, DavException, MessagingException {
            String result = null;
            // PropFind PR_INTERNET_CONTENT
            DavPropertyNameSet davPropertyNameSet = new DavPropertyNameSet();
            davPropertyNameSet.add(PR_INTERNET_CONTENT);
            PropFindMethod propFindMethod = new PropFindMethod(URIUtil.encodePath(permanentUrl), davPropertyNameSet, 0);
            try {
                DavGatewayHttpClientFacade.executeHttpMethod(httpClient, propFindMethod);
                MultiStatus responses = propFindMethod.getResponseBodyAsMultiStatus();
                if (responses.getResponses().length > 0) {
                    DavPropertySet properties = responses.getResponses()[0].getProperties(HttpStatus.SC_OK);
                    DavProperty property = properties.get(PR_INTERNET_CONTENT);
                    if (property != null) {
                        byte[] byteArray = Base64.decodeBase64(((String) property.getValue()).getBytes());
                        result = getICS(new ByteArrayInputStream(byteArray));
                    }
                }
            } finally {
                propFindMethod.releaseConnection();
            }
            return result;
        }

        /**
         * Load ICS content from Exchange server.
         * User Translate: f header to get MIME event content and get ICS attachment from it
         *
         * @return ICS (iCalendar) event
         * @throws IOException on error
         */
        public String getICS() throws IOException {
            String result;
            LOGGER.debug("Get event: " + permanentUrl);
            // try to get PR_INTERNET_CONTENT
            try {
                result = getICSFromInternetContentProperty();
                if (result == null) {
                    GetMethod method = new GetMethod(permanentUrl);
                    method.setRequestHeader("Content-Type", "text/xml; charset=utf-8");
                    method.setRequestHeader("Translate", "f");
                    try {
                        DavGatewayHttpClientFacade.executeGetMethod(httpClient, method, false);
                        result = getICS(method.getResponseBodyAsStream());
                    } finally {
                        method.releaseConnection();
                    }
                }
            } catch (DavException e) {
                throw buildHttpException(e);
            } catch (IOException e) {
                throw buildHttpException(e);
            } catch (MessagingException e) {
                throw buildHttpException(e);
            }
            return result;
        }

        protected HttpException buildHttpException(Exception e) {
            String message = "Unable to get event " + getName() + " at " + permanentUrl + ": " + e.getMessage();
            LOGGER.warn(message);
            return new HttpException(message);
        }

        /**
         * Get event name (file name part in URL).
         *
         * @return event name
         */
        public String getName() {
            int index = href.lastIndexOf('/');
            if (index >= 0) {
                return href.substring(index + 1);
            } else {
                return href;
            }
        }

        /**
         * Get event etag (last change tag).
         *
         * @return event etag
         */
        public String getEtag() {
            return etag;
        }

        protected String fixTimezoneId(String line, String validTimezoneId) {
            return StringUtil.replaceToken(line, "TZID=", ":", validTimezoneId);
        }

        protected void splitExDate(ICSBufferedWriter result, String line) {
            int cur = line.lastIndexOf(':') + 1;
            String start = line.substring(0, cur);

            for (int next = line.indexOf(',', cur); next != -1; next = line.indexOf(',', cur)) {
                String val = line.substring(cur, next);
                result.writeLine(start + val);

                cur = next + 1;
            }

            result.writeLine(start + line.substring(cur));
        }

        protected String getAllDayLine(String line) throws IOException {
            int keyIndex = line.indexOf(';');
            int valueIndex = line.lastIndexOf(':');
            int valueEndIndex = line.lastIndexOf('T');
            if (valueIndex < 0 || valueEndIndex < 0) {
                throw new DavMailException("EXCEPTION_INVALID_ICS_LINE", line);
            }
            String dateValue = line.substring(valueIndex + 1, valueEndIndex);
            String key = line.substring(0, Math.max(keyIndex, valueIndex));
            return key + ";VALUE=DATE:" + dateValue;
        }

        protected String fixICS(String icsBody, boolean fromServer) throws IOException {
            // first pass : detect
            class AllDayState {
                boolean isAllDay;
                boolean hasCdoAllDay;
                boolean isCdoAllDay;
            }

            dumpIndex++;
            dumpICS(icsBody, fromServer, false);

            // Convert event class from and to iCal
            // See https://trac.calendarserver.org/browser/CalendarServer/trunk/doc/Extensions/caldav-privateevents.txt
            boolean isAppleiCal = false;
            boolean hasAttendee = false;
            boolean hasCdoBusyStatus = false;
            // detect ics event with empty timezone (all day from Lightning)
            boolean hasTimezone = false;
            String transp = null;
            String validTimezoneId = null;
            String eventClass = null;
            String organizer = null;
            String action = null;
            boolean sound = false;

            List<AllDayState> allDayStates = new ArrayList<AllDayState>();
            AllDayState currentAllDayState = new AllDayState();
            BufferedReader reader = null;
            try {
                reader = new ICSBufferedReader(new StringReader(icsBody));
                String line;
                while ((line = reader.readLine()) != null) {
                    int index = line.indexOf(':');
                    if (index >= 0) {
                        String key = line.substring(0, index);
                        String value = line.substring(index + 1);
                        if ("DTSTART;VALUE=DATE".equals(key)) {
                            currentAllDayState.isAllDay = true;
                        } else if ("X-MICROSOFT-CDO-ALLDAYEVENT".equals(key)) {
                            currentAllDayState.hasCdoAllDay = true;
                            currentAllDayState.isCdoAllDay = "TRUE".equals(value);
                        } else if ("END:VEVENT".equals(line)) {
                            allDayStates.add(currentAllDayState);
                            currentAllDayState = new AllDayState();
                        } else if ("PRODID".equals(key) && line.contains("iCal")) {
                            // detect iCal created events
                            isAppleiCal = true;
                        } else if (isAppleiCal && "X-CALENDARSERVER-ACCESS".equals(key)) {
                            eventClass = value;
                        } else if (!isAppleiCal && "CLASS".equals(key)) {
                            eventClass = value;
                        } else if ("ACTION".equals(key)) {
                            action = value;
                        } else if ("ATTACH;VALUES=URI".equals(key)) {
                            // This is a marker that this event has an alarm with sound
                            sound = true;
                        } else if (key.startsWith("ORGANIZER")) {
                            if (value.startsWith("MAILTO:")) {
                                organizer = value.substring(7);
                            } else {
                                organizer = value;
                            }
                        } else if (key.startsWith("ATTENDEE")) {
                            hasAttendee = true;
                        } else if ("TRANSP".equals(key)) {
                            transp = value;
                        } else if (line.startsWith("TZID:(GMT") ||
                                // additional test for Outlook created recurring events
                                line.startsWith("TZID:GMT ")) {
                            try {
                                validTimezoneId = ResourceBundle.getBundle("timezones").getString(value);
                            } catch (MissingResourceException mre) {
                                LOGGER.warn(new BundleMessage("LOG_INVALID_TIMEZONE", value));
                            }
                        } else if ("X-MICROSOFT-CDO-BUSYSTATUS".equals(key)) {
                            hasCdoBusyStatus = true;
                        } else if ("BEGIN:VTIMEZONE".equals(line)) {
                            hasTimezone = true;
                        }
                    }
                }
            } finally {
                if (reader != null) {
                    reader.close();
                }
            }
            // second pass : fix
            int count = 0;
            ICSBufferedWriter result = new ICSBufferedWriter();
            try {
                reader = new ICSBufferedReader(new StringReader(icsBody));
                String line;

                while ((line = reader.readLine()) != null) {
                    // remove empty properties
                    if ("CLASS:".equals(line) || "LOCATION:".equals(line)) {
                        continue;
                    }
                    // fix invalid exchange timezoneid
                    if (validTimezoneId != null && line.indexOf(";TZID=") >= 0) {
                        line = fixTimezoneId(line, validTimezoneId);
                    }
                    if (!fromServer && "BEGIN:VEVENT".equals(line) && !hasTimezone) {
                        result.write(ExchangeSession.this.getVTimezone().timezoneBody);
                        hasTimezone = true;
                    }
                    if (!fromServer && currentAllDayState.isAllDay && "X-MICROSOFT-CDO-ALLDAYEVENT:FALSE".equals(line)) {
                        line = "X-MICROSOFT-CDO-ALLDAYEVENT:TRUE";
                    } else if (!fromServer && "END:VEVENT".equals(line)) {
                        if (!hasCdoBusyStatus) {
                            result.writeLine("X-MICROSOFT-CDO-BUSYSTATUS:" + (!"TRANSPARENT".equals(transp) ? "BUSY" : "FREE"));
                        }
                        if (currentAllDayState.isAllDay && !currentAllDayState.hasCdoAllDay) {
                            result.writeLine("X-MICROSOFT-CDO-ALLDAYEVENT:TRUE");
                        }
                        // add organizer line to all events created in Exchange for active sync
                        if (organizer == null) {
                            result.writeLine("ORGANIZER:MAILTO:" + email);
                        }
                    } else if (!fromServer && line.startsWith("X-MICROSOFT-CDO-BUSYSTATUS:")) {
                        line = "X-MICROSOFT-CDO-BUSYSTATUS:" + (!"TRANSPARENT".equals(transp) ? "BUSY" : "FREE");
                    } else if (!fromServer && !currentAllDayState.isAllDay && "X-MICROSOFT-CDO-ALLDAYEVENT:TRUE".equals(line)) {
                        line = "X-MICROSOFT-CDO-ALLDAYEVENT:FALSE";
                    } else if (fromServer && currentAllDayState.isCdoAllDay && line.startsWith("DTSTART") && !line.startsWith("DTSTART;VALUE=DATE")) {
                        line = getAllDayLine(line);
                    } else if (fromServer && currentAllDayState.isCdoAllDay && line.startsWith("DTEND") && !line.startsWith("DTEND;VALUE=DATE")) {
                        line = getAllDayLine(line);
                    } else if (!fromServer && currentAllDayState.isAllDay && line.startsWith("DTSTART") && line.startsWith("DTSTART;VALUE=DATE")) {
                        line = "DTSTART;TZID=\"" + ExchangeSession.this.getVTimezone().timezoneId + "\":" + line.substring(19) + "T000000";
                    } else if (!fromServer && currentAllDayState.isAllDay && line.startsWith("DTEND") && line.startsWith("DTEND;VALUE=DATE")) {
                        line = "DTEND;TZID=\"" + ExchangeSession.this.getVTimezone().timezoneId + "\":" + line.substring(17) + "T000000";
                    } else if (line.startsWith("TZID:") && validTimezoneId != null) {
                        line = "TZID:" + validTimezoneId;
                    } else if ("BEGIN:VEVENT".equals(line)) {
                        currentAllDayState = allDayStates.get(count++);
                    } else if (line.startsWith("X-CALENDARSERVER-ACCESS:")) {
                        if (!isAppleiCal) {
                            continue;
                        } else {
                            if ("CONFIDENTIAL".equalsIgnoreCase(eventClass)) {
                                result.writeLine("CLASS:PRIVATE");
                            } else if ("PRIVATE".equalsIgnoreCase(eventClass)) {
                                result.writeLine("CLASS:CONFIDENTIAL");
                            } else {
                                result.writeLine("CLASS:" + eventClass);
                            }
                        }
                    } else if (line.startsWith("EXDATE;TZID=") || line.startsWith("EXDATE:")) {
                        // Apple iCal doesn't support EXDATE with multiple exceptions
                        // on one line.  Split into multiple EXDATE entries (which is
                        // also legal according to the caldav standard).
                        splitExDate(result, line);
                        continue;
                    } else if (line.startsWith("X-ENTOURAGE_UUID:")) {
                        // Apple iCal doesn't understand this key, and it's entourage
                        // specific (i.e. not needed by any caldav client): strip it out
                        continue;
                    } else if (fromServer && line.startsWith("ATTENDEE;")
                            && (line.indexOf(email) >= 0)) {
                        // If this is coming from the server, strip out RSVP for this
                        // user as an attendee where the partstat is something other
                        // than PARTSTAT=NEEDS-ACTION since the RSVP confuses iCal4 into
                        // thinking the attendee has not replied

                        int rsvpSuffix = line.indexOf("RSVP=TRUE;");
                        int rsvpPrefix = line.indexOf(";RSVP=TRUE");

                        if (((rsvpSuffix >= 0) || (rsvpPrefix >= 0))
                                && (line.indexOf("PARTSTAT=") >= 0)
                                && (line.indexOf("PARTSTAT=NEEDS-ACTION") < 0)) {

                            // Strip out the "RSVP" line from the calendar entry
                            if (rsvpSuffix >= 0) {
                                line = line.substring(0, rsvpSuffix) + line.substring(rsvpSuffix + 10);
                            } else {
                                line = line.substring(0, rsvpPrefix) + line.substring(rsvpPrefix + 10);
                            }

                        }
                    } else if (line.startsWith("ACTION:")) {
                        if (fromServer && "DISPLAY".equals(action)
                                // convert DISPLAY to AUDIO only if user defined an alarm sound 
                                && Settings.getProperty("davmail.caldavAlarmSound") != null) {
                            // Convert alarm to audio for iCal
                            result.writeLine("ACTION:AUDIO");

                            if (!sound) {
                                // Add defined sound into the audio alarm
                                result.writeLine("ATTACH;VALUE=URI:" + Settings.getProperty("davmail.caldavAlarmSound"));
                            }

                            continue;
                        } else if (!fromServer && "AUDIO".equals(action)) {
                            // Use the alarm action that exchange (and blackberry) understand
                            // (exchange and blackberry don't understand audio actions)

                            result.writeLine("ACTION:DISPLAY");
                            continue;
                        }

                        // Don't recognize this type of action: pass it through

                    } else if (line.startsWith("CLASS:")) {
                        if (isAppleiCal) {
                            continue;
                        } else {
                            if ("PRIVATE".equalsIgnoreCase(eventClass)) {
                                result.writeLine("X-CALENDARSERVER-ACCESS:CONFIDENTIAL");
                            } else if ("CONFIDENTIAL".equalsIgnoreCase(eventClass)) {
                                result.writeLine("X-CALENDARSERVER-ACCESS:PRIVATE");
                            } else {
                                result.writeLine("X-CALENDARSERVER-ACCESS:" + eventClass);
                            }
                        }
                        // remove organizer line if user is organizer for iPhone
                    } else if (fromServer && line.startsWith("ORGANIZER") && !hasAttendee) {
                        continue;
                    } else if (organizer != null && line.startsWith("ATTENDEE") && line.contains(organizer)) {
                        // Ignore organizer as attendee
                        continue;
                    } else if (!fromServer && line.startsWith("ATTENDEE")) {
                        line = replaceIcal4Principal(line);
                    }

                    result.writeLine(line);
                }
            } finally {
                reader.close();
            }

            String resultString = result.toString();
            dumpICS(resultString, fromServer, true);

            return result.toString();
        }

        protected void dumpICS(String icsBody, boolean fromServer, boolean after) {
            String logFileDirectory = Settings.getLogFileDirectory();

            // additional setting to activate ICS dump (not available in GUI)
            int dumpMax = Settings.getIntProperty("davmail.dumpICS");
            if (dumpMax > 0) {
                if (dumpIndex > dumpMax) {
                    // Delete the oldest dump file
                    final int oldest = dumpIndex - dumpMax;
                    try {
                        File[] oldestFiles = (new File(logFileDirectory)).listFiles(new FilenameFilter() {
                            public boolean accept(File dir, String name) {
                                if (name.endsWith(".ics")) {
                                    int dashIndex = name.indexOf('-');
                                    if (dashIndex > 0) {
                                        try {
                                            int fileIndex = Integer.parseInt(name.substring(0, dashIndex));
                                            return fileIndex < oldest;
                                        } catch (NumberFormatException nfe) {
                                            // ignore
                                        }
                                    }
                                }
                                return false;
                            }
                        });
                        for (File file : oldestFiles) {
                            if (!file.delete()) {
                                LOGGER.warn("Unable to delete " + file.getAbsolutePath());
                            }
                        }
                    } catch (Exception ex) {
                        LOGGER.warn("Error deleting ics dump: " + ex.getMessage());
                    }
                }

                StringBuilder filePath = new StringBuilder();
                filePath.append(logFileDirectory).append('/')
                        .append(dumpIndex)
                        .append(after ? "-to" : "-from")
                        .append((after ^ fromServer) ? "-server" : "-client")
                        .append(".ics");
                if ((icsBody != null) && (icsBody.length() > 0)) {
                    FileWriter fileWriter = null;
                    try {
                        fileWriter = new FileWriter(filePath.toString());
                        fileWriter.write(icsBody);
                    } catch (IOException e) {
                        LOGGER.error(e);
                    } finally {
                        if (fileWriter != null) {
                            try {
                                fileWriter.close();
                            } catch (IOException e) {
                                LOGGER.error(e);
                            }
                        }
                    }


                }
            }

        }

        protected String getICSValue(String icsBody, String prefix, String defval) throws IOException {
            // only return values in VEVENT section, not VALARM
            Stack<String> sectionStack = new Stack<String>();
            BufferedReader reader = null;

            try {
                reader = new ICSBufferedReader(new StringReader(icsBody));
                String line;
                while ((line = reader.readLine()) != null) {
                    if (line.startsWith("BEGIN:")) {
                        sectionStack.push(line);
                    } else if (line.startsWith("END:") && !sectionStack.isEmpty()) {
                        sectionStack.pop();
                    } else if (!sectionStack.isEmpty() && "BEGIN:VEVENT".equals(sectionStack.peek()) && line.startsWith(prefix)) {
                        return line.substring(prefix.length());
                    }
                }

            } finally {
                if (reader != null) {
                    reader.close();
                }
            }

            return defval;
        }

        protected String getICSSummary(String icsBody) throws IOException {
            return getICSValue(icsBody, "SUMMARY:", BundleMessage.format("MEETING_REQUEST"));
        }

        protected String getICSDescription(String icsBody) throws IOException {
            return getICSValue(icsBody, "DESCRIPTION:", "");
        }

        class Participants {
            String attendees;
            String optionalAttendees;
            String organizer;
        }

        /**
         * Parse ics event for attendees and organizer.
         * For notifications, only include attendees with RSVP=TRUE or PARTSTAT=NEEDS-ACTION
         *
         * @param isNotification get only notified attendees
         * @return participants
         * @throws IOException on error
         */
        protected Participants getParticipants(boolean isNotification) throws IOException {
            HashSet<String> attendees = new HashSet<String>();
            HashSet<String> optionalAttendees = new HashSet<String>();
            String organizer = null;
            BufferedReader reader = null;
            try {
                reader = new ICSBufferedReader(new StringReader(icsBody));
                String line;
                while ((line = reader.readLine()) != null) {
                    int index = line.indexOf(':');
                    if (index >= 0) {
                        String key = line.substring(0, index);
                        String value = line.substring(index + 1);
                        int semiColon = key.indexOf(';');
                        if (semiColon >= 0) {
                            key = key.substring(0, semiColon);
                        }
                        if ("ORGANIZER".equals(key) || "ATTENDEE".equals(key)) {
                            int colonIndex = value.indexOf(':');
                            if (colonIndex >= 0) {
                                value = value.substring(colonIndex + 1);
                            }
                            value = replaceIcal4Principal(value);
                            if ("ORGANIZER".equals(key)) {
                                organizer = value;
                                // exclude current user and invalid values from recipients
                                // also exclude no action attendees
                            } else if (!email.equalsIgnoreCase(value) && value.indexOf('@') >= 0
                                    && (!isNotification
                                    || line.indexOf("RSVP=TRUE") >= 0
                                    || line.indexOf("PARTSTAT=NEEDS-ACTION") >= 0)) {
                                if (line.indexOf("ROLE=OPT-PARTICIPANT") >= 0) {
                                    optionalAttendees.add(value);
                                } else {
                                    attendees.add(value);
                                }
                            }
                        }
                    }
                }
            } finally {
                if (reader != null) {
                    reader.close();
                }
            }
            Participants participants = new Participants();
            participants.attendees = StringUtil.join(attendees, ", ");
            participants.optionalAttendees = StringUtil.join(optionalAttendees, ", ");
            participants.organizer = organizer;
            return participants;
        }

        protected String getICSMethod(String icsBody) {
            String icsMethod = StringUtil.getToken(icsBody, "METHOD:", "\r");
            if (icsMethod == null) {
                // default method is REQUEST
                icsMethod = "REQUEST";
            }
            return icsMethod;
        }

        protected EventResult createOrUpdate() throws IOException {
            String boundary = UUID.randomUUID().toString();
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            MimeOutputStreamWriter writer = new MimeOutputStreamWriter(baos);
            int status = 0;
            PutMethod putmethod = new PutMethod(URIUtil.encodePath(href));
            putmethod.setRequestHeader("Translate", "f");
            putmethod.setRequestHeader("Overwrite", "f");
            if (etag != null) {
                putmethod.setRequestHeader("If-Match", etag);
            }
            if (noneMatch != null) {
                putmethod.setRequestHeader("If-None-Match", noneMatch);
            }
            putmethod.setRequestHeader("Content-Type", "message/rfc822");
            String method = getICSMethod(icsBody);

            writer.writeHeader("Content-Transfer-Encoding", "7bit");
            writer.writeHeader("Content-class", contentClass);
            // append date
            writer.writeHeader("Date", new Date());

            // Make sure invites have a proper subject line
            writer.writeHeader("Subject", getICSSummary(icsBody));

            if ("urn:content-classes:calendarmessage".equals(contentClass)) {
                // need to parse attendees and organizer to build recipients
                Participants participants = getParticipants(true);
                if (email.equalsIgnoreCase(participants.organizer)) {
                    // current user is organizer => notify all
                    writer.writeHeader("To", participants.attendees);
                    writer.writeHeader("Cc", participants.optionalAttendees);
                    // do not send notification if no recipients found
                   if (participants.attendees == null && participants.optionalAttendees == null) {
                       status = HttpStatus.SC_NO_CONTENT;
                   }
                } else {
                    // notify only organizer
                    writer.writeHeader("To", participants.organizer);
                    // do not send notification if no recipients found
                   if (participants.organizer == null) {
                       status = HttpStatus.SC_NO_CONTENT;
                   }
                }

            } else {
                // need to parse attendees and organizer to build recipients
                Participants participants = getParticipants(false);
                // storing appointment, full recipients header
                if (participants.attendees != null) {
                    writer.writeHeader("To", participants.attendees);
                } else {
                    // use current user as attendee
                    writer.writeHeader("To", email);
                }
                writer.writeHeader("Cc", participants.optionalAttendees);

                if (participants.organizer != null) {
                    writer.writeHeader("From", participants.organizer);
                } else {
                    writer.writeHeader("From", email);
                }
                // if not organizer, set REPLYTIME to force Outlook in attendee mode
                if (participants.organizer != null && !email.equalsIgnoreCase(participants.organizer)) {
                    if (icsBody.indexOf("METHOD:") < 0) {
                        icsBody = icsBody.replaceAll("BEGIN:VCALENDAR", "BEGIN:VCALENDAR\r\nMETHOD:REQUEST");
                    }
                    if (icsBody.indexOf("X-MICROSOFT-CDO-REPLYTIME") < 0) {
                        icsBody = icsBody.replaceAll("END:VEVENT", "X-MICROSOFT-CDO-REPLYTIME:" +
                                getZuluDateFormat().format(new Date()) + "\r\nEND:VEVENT");
                    }
                }
            }
            writer.writeHeader("MIME-Version", "1.0");
            writer.writeHeader("Content-Type", "multipart/alternative;\r\n"+
            "\tboundary=\"----=_NextPart_"+boundary+"\"");
            writer.writeLn();
            writer.writeLn("This is a multi-part message in MIME format.");
            writer.writeLn();
            writer.writeLn("------=_NextPart_"+boundary);

            // Write a part of the message that contains the
            // ICS description so that invites contain the description text
            String description = getICSDescription(icsBody).replaceAll("\\\\[Nn]", "\r\n");

            if (description.length() > 0) {
                writer.writeHeader("Content-Type", "text/plain;\r\n" +
                        "\tcharset=\"utf-8\"");
                writer.writeHeader("content-transfer-encoding", "8bit");
                writer.writeLn();
                writer.flush();
                baos.write(description.getBytes("UTF-8"));
                writer.writeLn();
                writer.writeLn("------=_NextPart_"+boundary);
            }
            writer.writeHeader("Content-class", contentClass);
            writer.writeHeader("Content-Type", "text/calendar;\r\n"+
                    "\tmethod="+method+";\r\n"+
                    "\tcharset=\"utf-8\""
            );
            writer.writeHeader("Content-Transfer-Encoding", "8bit");
            writer.writeLn();
            writer.flush();
            baos.write(fixICS(icsBody, false).getBytes("UTF-8"));
            writer.writeLn();
            writer.writeLn("------=_NextPart_"+boundary+"--");
            writer.close();
            putmethod.setRequestEntity(new ByteArrayRequestEntity(baos.toByteArray(), "message/rfc822"));
            try {
                if (status == 0) {
                    status = httpClient.executeMethod(putmethod);
                    if (status == HttpURLConnection.HTTP_OK) {
                        if (etag != null) {
                            LOGGER.debug("Updated event " + href);
                        } else {
                            LOGGER.warn("Overwritten event " + href);
                        }
                    } else if (status != HttpURLConnection.HTTP_CREATED) {
                        LOGGER.warn("Unable to create or update message " + status + ' ' + putmethod.getStatusLine());
                    }
                }
            } finally {
                putmethod.releaseConnection();
            }
            EventResult eventResult = new EventResult();
            // 440 means forbidden on Exchange
            if (status == 440) {
                status = HttpStatus.SC_FORBIDDEN;
            }
            eventResult.status = status;
            if (putmethod.getResponseHeader("GetETag") != null) {
                eventResult.etag = putmethod.getResponseHeader("GetETag").getValue();
            }

            // trigger activeSync push event, only if davmail.forceActiveSyncUpdate setting is true
            if ((status == HttpStatus.SC_OK || status == HttpStatus.SC_CREATED) &&
                    (Settings.getBooleanProperty("davmail.forceActiveSyncUpdate"))) {
                ArrayList<DavProperty> propertyList = new ArrayList<DavProperty>();
                // Set contentclass to make ActiveSync happy
                propertyList.add(new DefaultDavProperty(DavPropertyName.create("contentclass", Namespace.getNamespace("DAV:")), contentClass));
                // ... but also set PR_INTERNET_CONTENT to preserve custom properties
                propertyList.add(new DefaultDavProperty(PR_INTERNET_CONTENT, new String(Base64.encodeBase64(baos.toByteArray()))));
                PropPatchMethod propPatchMethod = new PropPatchMethod(URIUtil.encodePath(href), propertyList);
                int patchStatus = DavGatewayHttpClientFacade.executeHttpMethod(httpClient, propPatchMethod);
                if (patchStatus != HttpStatus.SC_MULTI_STATUS) {
                    LOGGER.warn("Unable to patch event to trigger activeSync push");
                } else {
                    // need to retrieve new etag
                    Event newEvent = getEvent(href);
                    eventResult.etag = newEvent.etag;
                }
            }
            return eventResult;

        }
    }

    /**
     * Search calendar messages in provided folder.
     *
     * @param folderPath Exchange folder path
     * @return list of calendar messages as Event objects
     * @throws IOException on error
     */
    public List<Event> getEventMessages(String folderPath) throws IOException {
        List<Event> result;
        try {
            String searchQuery = "Select \"DAV:getetag\", \"http://schemas.microsoft.com/exchange/permanenturl\"" +
                    "                FROM Scope('SHALLOW TRAVERSAL OF \"" + folderPath + "\"')\n" +
                    "                WHERE \"DAV:contentclass\" = 'urn:content-classes:calendarmessage'\n" +
                    "                AND (NOT \"" + scheduleStateProperty.getNamespace().getURI() + scheduleStateProperty.getName() + "\" = 'CALDAV:schedule-processed')\n" +
                    "                ORDER BY \"urn:schemas:calendar:dtstart\" DESC\n";
            result = getEvents(folderPath, searchQuery);
        } catch (HttpException e) {
            // failover to DAV:comment property on some Exchange servers
            if (DEFAULT_SCHEDULE_STATE_PROPERTY.equals(scheduleStateProperty)) {
                scheduleStateProperty = DavPropertyName.create("comment", Namespace.getNamespace("DAV:"));
                result = getEventMessages(folderPath);
            } else {
                throw e;
            }
        }
        return result;
    }

    /**
     * Search calendar events in provided folder.
     *
     * @param folderPath Exchange folder path
     * @return list of calendar events
     * @throws IOException on error
     */
    public List<Event> getAllEvents(String folderPath) throws IOException {
        int caldavPastDelay = Settings.getIntProperty("davmail.caldavPastDelay", Integer.MAX_VALUE);
        String dateCondition = "";
        if (caldavPastDelay != Integer.MAX_VALUE) {
            Calendar cal = Calendar.getInstance();
            cal.add(Calendar.DAY_OF_MONTH, -caldavPastDelay);
            dateCondition = "                AND \"urn:schemas:calendar:dtstart\" > '" + formatSearchDate(cal.getTime()) + "'\n";
        }

        String searchQuery = "Select \"DAV:getetag\", \"http://schemas.microsoft.com/exchange/permanenturl\", \"urn:schemas:calendar:instancetype\"" +
                "                FROM Scope('SHALLOW TRAVERSAL OF \"" + folderPath + "\"')\n" +
                "                WHERE (" +
                // VTODO events have a null instancetype
                "                       \"urn:schemas:calendar:instancetype\" is null OR" +
                "                       \"urn:schemas:calendar:instancetype\" = 1\n" +
                "                OR (\"urn:schemas:calendar:instancetype\" = 0\n" +
                dateCondition +
                "                )) AND \"DAV:contentclass\" = 'urn:content-classes:appointment'\n" +
                "                ORDER BY \"urn:schemas:calendar:dtstart\" DESC\n";
        return getEvents(folderPath, searchQuery);
    }


    /**
     * Search calendar events or messages in provided folder matching the search query.
     *
     * @param folderPath  Exchange folder path
     * @param searchQuery Exchange search query
     * @return list of calendar messages as Event objects
     * @throws IOException on error
     */
    protected List<Event> getEvents(String folderPath, String searchQuery) throws IOException {
        List<Event> events = new ArrayList<Event>();
        MultiStatusResponse[] responses = DavGatewayHttpClientFacade.executeSearchMethod(httpClient, URIUtil.encodePath(folderPath), searchQuery);
        for (MultiStatusResponse response : responses) {
            String instancetype = getPropertyIfExists(response.getProperties(HttpStatus.SC_OK), "instancetype", Namespace.getNamespace("urn:schemas:calendar:"));
            Event event = buildEvent(response);
            if (instancetype == null && event.getICS() == null) {
                LOGGER.warn("Invalid event found at " + response.getHref());
            } else {
                events.add(event);
            }
        }
        return events;
    }

    /**
     * Get event named eventName in folder
     *
     * @param folderPath Exchange folder path
     * @param eventName  event name
     * @return event object
     * @throws IOException on error
     */
    public Event getEvent(String folderPath, String eventName) throws IOException {
        String eventPath = folderPath + '/' + eventName;
        Event event;
        try {
            event = getEvent(eventPath);
        } catch (HttpNotFoundException hnfe) {
            // failover for Exchange 2007 plus encoding issue
            String decodedEventName = eventName.replaceAll("_xF8FF_", "/").replaceAll("_x003F_", "?").replaceAll("'", "''");
            ExchangeSession.MessageList messages = searchMessages(folderPath, " AND \"DAV:displayname\"='" + decodedEventName + '\'');
            if (!messages.isEmpty()) {
                event = getEvent(messages.get(0).getPermanentUrl());
            } else {
                throw hnfe;
            }
        }

        return event;
    }

    /**
     * Get event by url
     *
     * @param eventPath Event path
     * @return event object
     * @throws IOException on error
     */
    public Event getEvent(String eventPath) throws IOException {
        MultiStatusResponse[] responses = DavGatewayHttpClientFacade.executePropFindMethod(httpClient, URIUtil.encodePath(eventPath), 0, EVENT_REQUEST_PROPERTIES);
        if (responses.length == 0) {
            throw new DavMailException("EXCEPTION_EVENT_NOT_FOUND");
        }
        return buildEvent(responses[0]);
    }

    /**
     * Delete event named eventName in folder
     *
     * @param folderPath Exchange folder path
     * @param eventName  event name
     * @return HTTP status
     * @throws IOException on error
     */
    public int deleteEvent(String folderPath, String eventName) throws IOException {
        String eventPath = URIUtil.encodePath(folderPath + '/' + eventName);
        int status;
        if (inboxUrl.endsWith(folderPath)) {
            // do not delete calendar messages, mark read and processed
            ArrayList<DavProperty> list = new ArrayList<DavProperty>();
            list.add(new DefaultDavProperty(scheduleStateProperty, "CALDAV:schedule-processed"));
            list.add(new DefaultDavProperty(DavPropertyName.create("read", URN_SCHEMAS_HTTPMAIL), "1"));
            PropPatchMethod patchMethod = new PropPatchMethod(eventPath, list);
            DavGatewayHttpClientFacade.executeMethod(httpClient, patchMethod);
            status = HttpStatus.SC_OK;
        } else {
            status = DavGatewayHttpClientFacade.executeDeleteMethod(httpClient, eventPath);
        }
        return status;
    }

    protected Event buildEvent(MultiStatusResponse calendarResponse) throws URIException {
        Event event = new Event();
        event.href = URIUtil.decode(calendarResponse.getHref());
        event.permanentUrl = getPropertyIfExists(calendarResponse.getProperties(HttpStatus.SC_OK), "permanenturl", SCHEMAS_EXCHANGE);
        event.etag = getPropertyIfExists(calendarResponse.getProperties(HttpStatus.SC_OK), "getetag", Namespace.getNamespace("DAV:"));
        return event;
    }

    private static int dumpIndex;

    /**
     * Replace iCal4 (Snow Leopard) principal paths with mailto expression
     *
     * @param value attendee value or ics line
     * @return fixed value
     */
    protected String replaceIcal4Principal(String value) {
        if (value.contains("/principals/__uuids__/")) {
            return value.replaceAll("/principals/__uuids__/([^/]*)__AT__([^/]*)/", "mailto:$1@$2");
        } else {
            return value;
        }
    }

    /**
     * Event result object to hold HTTP status and event etag from an event creation/update.
     */
    public static class EventResult {
        /**
         * HTTP status
         */
        public int status;
        /**
         * Event etag from response HTTP header
         */
        public String etag;
    }

    /**
     * Build and send the MIME message for the provided ICS event.
     *
     * @param icsBody event in iCalendar format
     * @return HTTP status
     * @throws IOException on error
     */
    public int sendEvent(String icsBody) throws IOException {
        String messageUrl = draftsUrl + '/' + UUID.randomUUID().toString() + ".EML";
        int status = internalCreateOrUpdateEvent(messageUrl, "urn:content-classes:calendarmessage", icsBody, null, null).status;
        if (status != HttpStatus.SC_CREATED) {
            return status;
        } else {
            MoveMethod method = new MoveMethod(URIUtil.encodePath(messageUrl), URIUtil.encodePath(sendmsgUrl), true);
            status = DavGatewayHttpClientFacade.executeHttpMethod(httpClient, method);
            if (status != HttpStatus.SC_OK) {
                throw DavGatewayHttpClientFacade.buildHttpException(method);
            }
            return status;
        }
    }

    /**
     * Create or update event on the Exchange server
     *
     * @param folderPath Exchange folder path
     * @param eventName  event name
     * @param icsBody    event body in iCalendar format
     * @param etag       previous event etag to detect concurrent updates
     * @param noneMatch  if-none-match header value
     * @return HTTP response event result (status and etag)
     * @throws IOException on error
     */
    public EventResult createOrUpdateEvent(String folderPath, String eventName, String icsBody, String etag, String noneMatch) throws IOException {
        String messageUrl = folderPath + '/' + eventName;
        return internalCreateOrUpdateEvent(messageUrl, "urn:content-classes:appointment", icsBody, etag, noneMatch);
    }

    protected EventResult internalCreateOrUpdateEvent(String messageUrl, String contentClass, String icsBody, String etag, String noneMatch) throws IOException {
        Event event = new Event();
        event.contentClass = contentClass;
        event.icsBody = icsBody;
        event.href = messageUrl;
        event.etag = etag;
        event.noneMatch = noneMatch;
        return event.createOrUpdate();
    }

    /**
     * Get folder ctag (change tag).
     * This flag changes whenever folder or folder content changes
     *
     * @param folderPath Exchange folder path
     * @return folder ctag
     * @throws IOException on error
     */
    public String getFolderCtag(String folderPath) throws IOException {
        return getFolderProperty(folderPath, CONTENT_TAG);
    }

    /**
     * Get folder resource tag.
     * Same as etag for folders, changes when folder (not content) changes
     *
     * @param folderPath Exchange folder path
     * @return folder resource tag
     * @throws IOException on error
     */
    public String getFolderResourceTag(String folderPath) throws IOException {
        return getFolderProperty(folderPath, RESOURCE_TAG);
    }

    protected String getFolderProperty(String folderPath, DavPropertyNameSet davPropertyNameSet) throws IOException {
        String result;
        MultiStatusResponse[] responses = DavGatewayHttpClientFacade.executePropFindMethod(
                httpClient, URIUtil.encodePath(folderPath), 0, davPropertyNameSet);
        if (responses.length == 0) {
            throw new DavMailException("EXCEPTION_UNABLE_TO_GET_FOLDER", folderPath);
        }
        DavPropertySet properties = responses[0].getProperties(HttpStatus.SC_OK);
        DavPropertyName davPropertyName = davPropertyNameSet.iterator().nextPropertyName();
        result = getPropertyIfExists(properties, davPropertyName);
        if (result == null) {
            throw new DavMailException("EXCEPTION_UNABLE_TO_GET_PROPERTY", davPropertyName);
        }
        return result;
    }

    /**
     * Get current Exchange alias name from login name
     *
     * @return user name
     */
    protected String getAliasFromLogin() {
        // Exchange 2007 : userName is login without domain
        String result = this.userName;
        int index = result.indexOf('\\');
        if (index >= 0) {
            result = result.substring(index + 1);
        }
        return result;
    }

    /**
     * Get current Exchange alias name from mailbox name
     *
     * @return user name
     */
    protected String getAliasFromMailPath() {
        if (mailPath == null) {
            return null;
        }
        int index = mailPath.lastIndexOf('/', mailPath.length() - 2);
        if (index >= 0 && mailPath.endsWith("/")) {
            return mailPath.substring(index + 1, mailPath.length() - 1);
        } else {
            LOGGER.warn(new BundleMessage("EXCEPTION_INVALID_MAIL_PATH", mailPath));
            return null;
        }
    }

    /**
     * Get user alias from mailbox display name over Webdav.
     *
     * @return user alias
     */
    public String getAliasFromMailboxDisplayName() {
        if (mailPath == null) {
            return null;
        }
        String displayName = null;
        try {
            MultiStatusResponse[] responses = DavGatewayHttpClientFacade.executePropFindMethod(
                    httpClient, URIUtil.encodePath(mailPath), 0, DISPLAY_NAME);
            if (responses.length == 0) {
                LOGGER.warn(new BundleMessage("EXCEPTION_UNABLE_TO_GET_MAIL_FOLDER", mailPath));
            } else {
                displayName = getPropertyIfExists(responses[0].getProperties(HttpStatus.SC_OK), "displayname", Namespace.getNamespace("DAV:"));
            }
        } catch (IOException e) {
            LOGGER.warn(new BundleMessage("EXCEPTION_UNABLE_TO_GET_MAIL_FOLDER", mailPath));
        }
        return displayName;
    }

    /**
     * Build Caldav calendar path for principal and folder name.
     * - prefix is current user mailbox path if principal is current user,
     * else prefix is parent folder of current user mailbox path followed by principal
     * - suffix according to well known folder names (internationalized on Exchange)
     *
     * @param principal  calendar principal
     * @param folderName requested folder name
     * @return Exchange folder path
     * @throws IOException on error
     */
    public String buildCalendarPath(String principal, String folderName) throws IOException {
        StringBuilder buffer = new StringBuilder();
        // other user calendar => replace principal folder name in mailPath
        if (principal != null && !alias.equals(principal) && !email.equals(principal)) {
            LOGGER.debug("Detected shared calendar path for principal " + principal + ", user principal is " + email);
            int index = mailPath.lastIndexOf('/', mailPath.length() - 2);
            if (index >= 0 && mailPath.endsWith("/")) {
                buffer.append(mailPath.substring(0, index + 1)).append(principal).append('/');
            } else {
                throw new DavMailException("EXCEPTION_INVALID_MAIL_PATH", mailPath);
            }
        } else if (principal != null) {
            buffer.append(mailPath);
        }

        if (folderName != null && folderName.startsWith("calendar")) {
            // replace 'calendar' folder name with i18n name
            buffer.append(calendarUrl.substring(calendarUrl.lastIndexOf('/') + 1));

            // sub calendar folder => append sub folder name
            int index = folderName.indexOf('/');
            if (index >= 0) {
                buffer.append(folderName.substring(index));
            }
            // replace 'inbox' folder name with i18n name
        } else if ("inbox".equals(folderName)) {
            buffer.append(inboxUrl.substring(inboxUrl.lastIndexOf('/') + 1));
            // append folder name without replace (public folder)
        } else if (folderName != null && folderName.length() > 0) {
            buffer.append(folderName);
        }
        return buffer.toString();
    }

    /**
     * Build base path for cmd commands (galfind, gallookup).
     * This does not work with freebusy, which requires /public/
     *
     * @return cmd base path
     */
    public String getCmdBasePath() {
        if (mailPath == null) {
            if (publicFolderUrl == null) {
                return "/public/";
            } else {
                return publicFolderUrl + '/';
            }
        } else {
            return mailPath;
        }
    }

    /**
     * Get user email from global address list (galfind).
     *
     * @param alias user alias
     * @return user email
     */
    public String getEmail(String alias) {
        String emailResult = null;
        if (alias != null) {
            GetMethod getMethod = null;
            String path = null;
            try {
                path = getCmdBasePath() + "?Cmd=galfind&AN=" + URIUtil.encodeWithinQuery(alias);
                getMethod = new GetMethod(path);
                DavGatewayHttpClientFacade.executeGetMethod(httpClient, getMethod, true);
                Map<String, Map<String, String>> results = XMLStreamUtil.getElementContentsAsMap(getMethod.getResponseBodyAsStream(), "item", "AN");
                Map<String, String> result = results.get(alias.toLowerCase());
                if (result != null) {
                    emailResult = result.get("EM");
                }
            } catch (IOException e) {
                LOGGER.debug("GET " + path + " failed: " + e + ' ' + e.getMessage());
            } finally {
                if (getMethod != null) {
                    getMethod.releaseConnection();
                }
            }
        }
        return emailResult;
    }

    /**
     * Determine user email through various means.
     *
     * @param hostName   Exchange server host name for last failover
     * @param methodPath current httpclient method path
     */
    public void buildEmail(String hostName, String methodPath) {
        // first try to get email from login name
        alias = getAliasFromLogin();
        email = getEmail(alias);
        // failover: use mailbox name as alias
        if (email == null) {
            alias = getAliasFromMailPath();
            email = getEmail(alias);
        }
        // another failover : get alias from mailPath display name
        if (email == null) {
            alias = getAliasFromMailboxDisplayName();
            email = getEmail(alias);
        }
        if (email == null) {
            // failover : get email from Exchange 2007 Options page
            alias = getAliasFromOptions(methodPath);
            email = getEmail(alias);
            // failover: get email from options
            if (alias != null && email == null) {
                email = getEmailFromOptions(methodPath);
            }
        }
        if (email == null) {
            LOGGER.debug("Unable to get user email with alias " + getAliasFromLogin()
                    + " or " + getAliasFromMailPath()
                    + " or " + getAliasFromOptions(methodPath)
            );
            // last failover: build email from domain name and mailbox display name
            StringBuilder buffer = new StringBuilder();
            // most reliable alias
            alias = getAliasFromMailboxDisplayName();
            if (alias == null) {
                alias = getAliasFromLogin();
            }
            if (alias != null) {
                buffer.append(alias);
                if (alias.indexOf('@') < 0) {
                    buffer.append('@');
                    int dotIndex = hostName.indexOf('.');
                    if (dotIndex >= 0) {
                        buffer.append(hostName.substring(dotIndex + 1));
                    }
                }
            }
            email = buffer.toString();
        }
    }

    static final String MAILBOX_BASE = "cn=recipients/cn=";

    protected String getAliasFromOptions(String path) {
        String result = null;
        // get user mail URL from html body
        BufferedReader optionsPageReader = null;
        GetMethod optionsMethod = new GetMethod(path + "?ae=Options&t=About");
        try {
            DavGatewayHttpClientFacade.executeGetMethod(httpClient, optionsMethod, false);
            optionsPageReader = new BufferedReader(new InputStreamReader(optionsMethod.getResponseBodyAsStream()));
            String line;
            // find mailbox full name
            //noinspection StatementWithEmptyBody
            while ((line = optionsPageReader.readLine()) != null && line.toLowerCase().indexOf(MAILBOX_BASE) == -1) {
            }
            if (line != null) {
                int start = line.toLowerCase().indexOf(MAILBOX_BASE) + MAILBOX_BASE.length();
                int end = line.indexOf('<', start);
                result = line.substring(start, end);
            }
        } catch (IOException e) {
            LOGGER.error("Error parsing options page at " + optionsMethod.getPath());
        } finally {
            if (optionsPageReader != null) {
                try {
                    optionsPageReader.close();
                } catch (IOException e) {
                    LOGGER.error("Error parsing options page at " + optionsMethod.getPath());
                }
            }
            optionsMethod.releaseConnection();
        }

        return result;
    }

    protected String getEmailFromOptions(String path) {
        String result = null;
        // get user mail URL from html body
        BufferedReader optionsPageReader = null;
        GetMethod optionsMethod = new GetMethod(path + "?ae=Options&t=About");
        try {
            DavGatewayHttpClientFacade.executeGetMethod(httpClient, optionsMethod, false);
            optionsPageReader = new BufferedReader(new InputStreamReader(optionsMethod.getResponseBodyAsStream()));
            String line;
            // find email
            //noinspection StatementWithEmptyBody
            while ((line = optionsPageReader.readLine()) != null
                    && (line.indexOf('[') == -1
                    || line.indexOf('@') == -1
                    || line.indexOf(']') == -1)) {
            }
            if (line != null) {
                int start = line.toLowerCase().indexOf('[') + 1;
                int end = line.indexOf(']', start);
                result = line.substring(start, end);
            }
        } catch (IOException e) {
            LOGGER.error("Error parsing options page at " + optionsMethod.getPath());
        } finally {
            if (optionsPageReader != null) {
                try {
                    optionsPageReader.close();
                } catch (IOException e) {
                    LOGGER.error("Error parsing options page at " + optionsMethod.getPath());
                }
            }
            optionsMethod.releaseConnection();
        }

        return result;
    }

    /**
     * Get current user email
     *
     * @return user email
     */
    public String getEmail() {
        return email;
    }

    /**
     * Get current user alias
     *
     * @return user email
     */
    public String getAlias() {
        return alias;
    }

    /**
     * Search users in global address book
     *
     * @param searchAttribute exchange search attribute
     * @param searchValue     search value
     * @return List of users
     * @throws IOException on error
     */
    public Map<String, Map<String, String>> galFind(String searchAttribute, String searchValue) throws IOException {
        Map<String, Map<String, String>> results;
        GetMethod getMethod = new GetMethod(URIUtil.encodePathQuery(getCmdBasePath() + "?Cmd=galfind&" + searchAttribute + '=' + searchValue));
        try {
            DavGatewayHttpClientFacade.executeGetMethod(httpClient, getMethod, true);
            results = XMLStreamUtil.getElementContentsAsMap(getMethod.getResponseBodyAsStream(), "item", "AN");
        } finally {
            getMethod.releaseConnection();
        }
        LOGGER.debug("galfind " + searchAttribute + '=' + searchValue + ": " + results.size() + " result(s)");
        return results;
    }

    /**
     * Search users in contacts folder by uid.
     *
     * @param uid unique id
     * @return List of users
     * @throws IOException on error
     */
    public Map<String, Map<String, String>> contactFindByUid(String uid) throws IOException {
        return contactFind(DAV_UID_FILTER + uid + '\'');
    }

    static final String DAV_UID_FILTER = "\"DAV:uid\"='";

    /**
     * Search users in contacts folder
     *
     * @param searchFilter search filter
     * @return List of users
     * @throws IOException on error
     */
    public Map<String, Map<String, String>> contactFind(String searchFilter) throws IOException {
        // uid value in search filter (hex value)
        String filterUid = null;
        // base64 encoded uid value
        String actualFilterUid = null;

        // replace hex encoded uid with base64 uid
        if (searchFilter != null) {
            int uidStart = searchFilter.indexOf(DAV_UID_FILTER);
            if (uidStart >= 0) {
                int uidEnd = searchFilter.indexOf('\'', uidStart + DAV_UID_FILTER.length());
                if (uidEnd >= 0) {
                    try {
                        filterUid = searchFilter.substring(uidStart + DAV_UID_FILTER.length(), uidEnd);
                        actualFilterUid = new String(Base64.encodeBase64(Hex.decodeHex(filterUid.toCharArray())));
                        searchFilter = searchFilter.substring(0, uidStart + DAV_UID_FILTER.length()) + actualFilterUid + searchFilter.substring(uidEnd);
                    } catch (DecoderException e) {
                        // ignore, this is not an hex uid
                    }
                }
            }
        }
        StringBuilder searchRequest = new StringBuilder();
        searchRequest.append("Select \"DAV:uid\", " +
                "\"http://schemas.microsoft.com/exchange/extensionattribute1\"," +
                "\"http://schemas.microsoft.com/exchange/extensionattribute2\"," +
                "\"http://schemas.microsoft.com/exchange/extensionattribute3\"," +
                "\"http://schemas.microsoft.com/exchange/extensionattribute4\"," +
                "\"urn:schemas:contacts:bday\"," +
                "\"urn:schemas:contacts:businesshomepage\"," +
                "\"urn:schemas:contacts:c\"," +
                "\"urn:schemas:contacts:cn\"," +
                "\"urn:schemas:contacts:co\"," +
                "\"urn:schemas:contacts:department\"," +
                "\"urn:schemas:contacts:email1\"," +
                "\"urn:schemas:contacts:email2\"," +
                "\"urn:schemas:contacts:facsimiletelephonenumber\"," +
                "\"urn:schemas:contacts:givenName\"," +
                "\"urn:schemas:contacts:homeCity\"," +
                "\"urn:schemas:contacts:homeCountry\"," +
                "\"urn:schemas:contacts:homePhone\"," +
                "\"urn:schemas:contacts:homePostalCode\"," +
                "\"urn:schemas:contacts:homeState\"," +
                "\"urn:schemas:contacts:homeStreet\"," +
                "\"urn:schemas:contacts:l\"," +
                "\"urn:schemas:contacts:manager\"," +
                "\"urn:schemas:contacts:mobile\"," +
                "\"urn:schemas:contacts:namesuffix\"," +
                "\"urn:schemas:contacts:nickname\"," +
                "\"urn:schemas:contacts:o\"," +
                "\"urn:schemas:contacts:pager\"," +
                "\"urn:schemas:contacts:personaltitle\"," +
                "\"urn:schemas:contacts:postalcode\"," +
                "\"urn:schemas:contacts:postofficebox\"," +
                "\"urn:schemas:contacts:profession\"," +
                "\"urn:schemas:contacts:roomnumber\"," +
                "\"urn:schemas:contacts:secretarycn\"," +
                "\"urn:schemas:contacts:sn\"," +
                "\"urn:schemas:contacts:spousecn\"," +
                "\"urn:schemas:contacts:st\"," +
                "\"urn:schemas:contacts:street\"," +
                "\"urn:schemas:contacts:telephoneNumber\"," +
                "\"urn:schemas:contacts:title\"," +
                "\"urn:schemas:httpmail:textdescription\"")
                .append("                FROM Scope('SHALLOW TRAVERSAL OF \"").append(contactsUrl).append("\"')\n")
                .append("                WHERE \"DAV:contentclass\" = 'urn:content-classes:person' \n");
        if (searchFilter != null && searchFilter.length() > 0) {
            searchRequest.append("                AND ").append(searchFilter);
        }
        LOGGER.debug("contactFind: " + searchRequest);
        MultiStatusResponse[] responses = DavGatewayHttpClientFacade.executeSearchMethod(
                httpClient, URIUtil.encodePath(contactsUrl), searchRequest.toString());

        Map<String, Map<String, String>> results = new HashMap<String, Map<String, String>>();
        Map<String, String> item;
        for (MultiStatusResponse response : responses) {
            item = new HashMap<String, String>();

            DavPropertySet properties = response.getProperties(HttpStatus.SC_OK);
            DavPropertyIterator propertiesIterator = properties.iterator();
            while (propertiesIterator.hasNext()) {
                DavProperty property = propertiesIterator.nextProperty();
                String propertyName = property.getName().getName();
                String propertyValue = (String) property.getValue();
                if ("uid".equals(propertyName)) {
                    // uid is base64, reencode to hex
                    propertyValue = new String(Hex.encodeHex(Base64.decodeBase64(propertyValue.getBytes())));
                    // if actualFilterUid is not null, exclude non exact match
                    if (actualFilterUid != null && !filterUid.equals(propertyValue)) {
                        propertyValue = null;
                    }
                } else if (propertyName.startsWith("email")) {
                    if (propertyValue != null && propertyValue.startsWith("\"")) {
                        int endIndex = propertyValue.indexOf('\"', 1);
                        if (endIndex > 0) {
                            propertyValue = propertyValue.substring(1, endIndex);
                        }
                    }
                } else if ("bday".equals(propertyName)) {
                    SimpleDateFormat parser = getExchangeZuluDateFormatMillisecond();
                    try {
                        Calendar calendar = Calendar.getInstance();
                        calendar.setTime(parser.parse(propertyValue));
                        item.put("birthday", String.valueOf(calendar.get(Calendar.DAY_OF_MONTH)));
                        item.put("birthmonth", String.valueOf(calendar.get(Calendar.MONTH) + 1));
                        item.put("birthyear", String.valueOf(calendar.get(Calendar.YEAR)));
                        propertyValue = null;
                    } catch (ParseException e) {
                        throw new IOException(e);
                    }
                } else if ("textdescription".equals(propertyName) && " \n".equals(propertyValue)) {
                    propertyValue = null;
                }
                if (propertyValue != null && propertyValue.length() > 0) {
                    item.put(propertyName, propertyValue);
                }
            }
            if (item.get("uid") != null) {
                results.put(item.get("uid"), item);
            }
        }

        LOGGER.debug("contactFind " + ((searchFilter == null) ? "" : searchFilter) + ": " + results.size() + " result(s)");
        return results;
    }

    /**
     * Get extended address book information for person with gallookup.
     * Does not work with Exchange 2007
     *
     * @param person person attributes map
     */
    public void galLookup(Map<String, String> person) {
        if (!disableGalLookup) {
            GetMethod getMethod = null;
            try {
                getMethod = new GetMethod(URIUtil.encodePathQuery(getCmdBasePath() + "?Cmd=gallookup&ADDR=" + person.get("EM")));
                DavGatewayHttpClientFacade.executeGetMethod(httpClient, getMethod, true);
                Map<String, Map<String, String>> results = XMLStreamUtil.getElementContentsAsMap(getMethod.getResponseBodyAsStream(), "person", "alias");
                // add detailed information
                if (!results.isEmpty()) {
                    Map<String, String> fullperson = results.get(person.get("AN").toLowerCase());
                    if (fullperson != null) {
                        for (Map.Entry<String, String> entry : fullperson.entrySet()) {
                            person.put(entry.getKey(), entry.getValue());
                        }
                    }
                }
            } catch (IOException e) {
                LOGGER.warn("Unable to gallookup person: " + person + ", disable GalLookup");
                disableGalLookup = true;
            } finally {
                if (getMethod != null) {
                    getMethod.releaseConnection();
                }
            }
        }
    }

    /**
     * Get freebusy info for attendee between start and end date.
     *
     * @param attendee       attendee email
     * @param startDateValue start date
     * @param endDateValue   end date
     * @return FreeBusy info
     * @throws IOException on error
     */
    public FreeBusy getFreebusy(String attendee, String startDateValue, String endDateValue) throws IOException {
        attendee = replaceIcal4Principal(attendee);
        if (attendee.startsWith("mailto:") || attendee.startsWith("MAILTO:")) {
            attendee = attendee.substring("mailto:".length());
        }

        SimpleDateFormat exchangeZuluDateFormat = getExchangeZuluDateFormat();
        SimpleDateFormat icalDateFormat = getZuluDateFormat();

        String freebusyUrl;
        Date startDate;
        Date endDate;
        try {
            if (startDateValue.length() == 8) {
                startDate = parseDate(startDateValue);
            } else {
                startDate = icalDateFormat.parse(startDateValue);
            }
            if (endDateValue.length() == 8) {
                endDate = parseDate(endDateValue);
            } else {
                endDate = icalDateFormat.parse(endDateValue);
            }
            freebusyUrl = publicFolderUrl + "/?cmd=freebusy" +
                    "&start=" + exchangeZuluDateFormat.format(startDate) +
                    "&end=" + exchangeZuluDateFormat.format(endDate) +
                    "&interval=" + FREE_BUSY_INTERVAL +
                    "&u=SMTP:" + attendee;
        } catch (ParseException e) {
            throw new DavMailException("EXCEPTION_INVALID_DATES", e.getMessage());
        }

        FreeBusy freeBusy = null;
        GetMethod getMethod = new GetMethod(freebusyUrl);
        getMethod.setRequestHeader("Content-Type", "text/xml");

        try {
            DavGatewayHttpClientFacade.executeGetMethod(httpClient, getMethod, true);
            String fbdata = StringUtil.getLastToken(getMethod.getResponseBodyAsString(), "<a:fbdata>", "</a:fbdata>");
            if (fbdata != null) {
                freeBusy = new FreeBusy(icalDateFormat, startDate, fbdata);
            }
        } finally {
            getMethod.releaseConnection();
        }

        if (freeBusy != null && freeBusy.knownAttendee) {
            return freeBusy;
        } else {
            return null;
        }
    }

    /**
     * Exchange to iCalendar Free/Busy parser.
     * Free time returns 0, Tentative returns 1, Busy returns 2, and Out of Office (OOF) returns 3
     */
    public static final class FreeBusy {
        final SimpleDateFormat icalParser;
        boolean knownAttendee = true;
        static final HashMap<Character, String> FBTYPES = new HashMap<Character, String>();

        static {
            FBTYPES.put('1', "BUSY-TENTATIVE");
            FBTYPES.put('2', "BUSY");
            FBTYPES.put('3', "BUSY-UNAVAILABLE");
        }

        final HashMap<String, StringBuilder> busyMap = new HashMap<String, StringBuilder>();

        StringBuilder getBusyBuffer(char type) {
            String fbType = FBTYPES.get(Character.valueOf(type));
            StringBuilder buffer = busyMap.get(fbType);
            if (buffer == null) {
                buffer = new StringBuilder();
                busyMap.put(fbType, buffer);
            }
            return buffer;
        }

        void startBusy(char type, Calendar currentCal) {
            if (type == '4') {
                knownAttendee = false;
            } else if (type != '0') {
                StringBuilder busyBuffer = getBusyBuffer(type);
                if (busyBuffer.length() > 0) {
                    busyBuffer.append(',');
                }
                busyBuffer.append(icalParser.format(currentCal.getTime()));
            }
        }

        void endBusy(char type, Calendar currentCal) {
            if (type != '0' && type != '4') {
                getBusyBuffer(type).append('/').append(icalParser.format(currentCal.getTime()));
            }
        }

        FreeBusy(SimpleDateFormat icalParser, Date startDate, String fbdata) {
            this.icalParser = icalParser;
            if (fbdata.length() > 0) {
                Calendar currentCal = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
                currentCal.setTime(startDate);

                startBusy(fbdata.charAt(0), currentCal);
                for (int i = 1; i < fbdata.length() && knownAttendee; i++) {
                    currentCal.add(Calendar.MINUTE, FREE_BUSY_INTERVAL);
                    char previousState = fbdata.charAt(i - 1);
                    char currentState = fbdata.charAt(i);
                    if (previousState != currentState) {
                        endBusy(previousState, currentCal);
                        startBusy(currentState, currentCal);
                    }
                }
                currentCal.add(Calendar.MINUTE, FREE_BUSY_INTERVAL);
                endBusy(fbdata.charAt(fbdata.length() - 1), currentCal);
            }
        }

        /**
         * Append freebusy information to buffer.
         *
         * @param buffer String buffer
         */
        public void appendTo(StringBuilder buffer) {
            for (Map.Entry<String, StringBuilder> entry : busyMap.entrySet()) {
                buffer.append("FREEBUSY;FBTYPE=").append(entry.getKey())
                        .append(':').append(entry.getValue()).append((char) 13).append((char) 10);
            }
        }
    }

    protected final class VTimezone {
        private String timezoneBody;
        private String timezoneId;

        /**
         * create a fake event to get VTIMEZONE body
         */
        private void load() {
            try {
                // create temporary folder
                String folderPath = ExchangeSession.this.getFolderPath("davmailtemp");
                ExchangeSession.this.createCalendarFolder(folderPath);

                PostMethod postMethod = new PostMethod(URIUtil.encodePath(folderPath));
                postMethod.addParameter("Cmd", "saveappt");
                postMethod.addParameter("FORMTYPE", "appointment");
                String fakeEventUrl = null;
                try {
                    // create fake event
                    int statusCode = ExchangeSession.this.httpClient.executeMethod(postMethod);
                    if (statusCode == HttpStatus.SC_OK) {
                        fakeEventUrl = StringUtil.getToken(postMethod.getResponseBodyAsString(), "<span id=\"itemHREF\">", "</span>");
                    }
                } finally {
                    postMethod.releaseConnection();
                }
                // failover for Exchange 2007, use PROPPATCH with forced timezone
                if (fakeEventUrl == null) {
                    ArrayList<DavProperty> propertyList = new ArrayList<DavProperty>();
                    propertyList.add(new DefaultDavProperty(DavPropertyName.create("contentclass", Namespace.getNamespace("DAV:")), "urn:content-classes:appointment"));
                    propertyList.add(new DefaultDavProperty(DavPropertyName.create("outlookmessageclass", Namespace.getNamespace("http://schemas.microsoft.com/exchange/")), "IPM.Appointment"));
                    propertyList.add(new DefaultDavProperty(DavPropertyName.create("instancetype", Namespace.getNamespace("urn:schemas:calendar:")), "0"));
                    // get forced timezone id from settings
                    timezoneId = Settings.getProperty("davmail.timezoneId");
                    if (timezoneId != null) {
                        propertyList.add(new DefaultDavProperty(DavPropertyName.create("timezoneid", Namespace.getNamespace("urn:schemas:calendar:")), timezoneId));
                    }
                    String patchMethodUrl = URIUtil.encodePath(folderPath) + '/' + UUID.randomUUID().toString() + ".EML";
                    PropPatchMethod patchMethod = new PropPatchMethod(URIUtil.encodePath(patchMethodUrl), propertyList);
                    try {
                        int statusCode = httpClient.executeMethod(patchMethod);
                        if (statusCode == HttpStatus.SC_MULTI_STATUS) {
                            fakeEventUrl = patchMethodUrl;
                        }
                    } finally {
                        patchMethod.releaseConnection();
                    }
                }
                if (fakeEventUrl != null) {
                    // get fake event body
                    GetMethod getMethod = new GetMethod(URIUtil.encodePath(fakeEventUrl));
                    getMethod.setRequestHeader("Translate", "f");
                    try {
                        ExchangeSession.this.httpClient.executeMethod(getMethod);
                        timezoneBody = "BEGIN:VTIMEZONE" +
                                StringUtil.getToken(getMethod.getResponseBodyAsString(), "BEGIN:VTIMEZONE", "END:VTIMEZONE") +
                                "END:VTIMEZONE\r\n";
                        timezoneId = StringUtil.getToken(timezoneBody, "TZID:", "\r\n");
                    } finally {
                        getMethod.releaseConnection();
                    }
                }

                // delete temporary folder
                ExchangeSession.this.deleteFolder("davmailtemp");
            } catch (IOException e) {
                LOGGER.warn("Unable to get VTIMEZONE info: " + e, e);
            }
        }
    }

    protected VTimezone vTimezone;

    protected VTimezone getVTimezone() {
        if (vTimezone == null) {
            // need to load Timezone info from OWA
            vTimezone = new VTimezone();
            vTimezone.load();
        }
        return vTimezone;
    }

    /**
     * Return internal HttpClient instance
     *
     * @return http client
     */
    public HttpClient getHttpClient() {
        return httpClient;
    }
}