/*
 *  eXist Open Source Native XML Database
 *  Copyright (C) 2001-2014 The eXist Project
 *  http://exist-db.org
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public License
 *  as published by the Free Software Foundation; either version 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 Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 *  $Id$
 */

package org.exist.dom.persistent;

import java.io.IOException;

import org.exist.security.UUIDGenerator;
import org.exist.storage.io.VariableByteInput;
import org.exist.storage.io.VariableByteOutputStream;

/**
 * Class representing a locktoken. Introduced for webDAV locking.
 *
 * @author Dannes Wessels
 */
public class LockToken {

    // Lock type
    private byte type = LOCK_TYPE_NOT_SET;
    public static final byte LOCK_TYPE_NONE = 0;
    public static final byte LOCK_TYPE_WRITE = 1;
    public static final byte LOCK_TYPE_NOT_SET = 4;

    // Lock depth
    private byte depth = LOCK_DEPTH_NOT_SET;
    public static final byte LOCK_DEPTH_0 = 0;
    public static final byte LOCK_DEPTH_1 = 1;
    public static final byte LOCK_DEPTH_INFINIY = 2;
    public static final byte LOCK_DEPTH_NOT_SET = 4;

    // Lock scope
    private byte scope = LOCK_SCOPE_NOT_SET;
    public static final byte LOCK_SCOPE_NONE = 0;
    public static final byte LOCK_SCOPE_EXCLUSIVE = 1;
    public static final byte LOCK_SCOPE_SHARED = 2;
    public static final byte LOCK_SCOPE_NOT_SET = 4;

    // Timeout
    public static final long LOCK_TIMEOUT_INFINITE = -1L;
    public static final long NO_LOCK_TIMEOUT = -2L;

    // Write Locks and Null Resources
    // see http://www.webdav.org/specs/rfc2518.html#rfc.section.7.4
    private byte resourceType = RESOURCE_TYPE_NOT_SPECIFIED;
    public static final byte RESOURCE_TYPE_NOT_SPECIFIED = 0;
    public static final byte RESOURCE_TYPE_NULL_RESOURCE = 1;

    // Other
    private String owner = null;
    private long timeout = -1L;
    private String token = null;

    /**
     * Creates a new instance of LockToken
     */
    public LockToken() {
        // Left empty intentionally
    }

    // Getters and setters

    /**
     * Get type of lock.
     */
    public byte getType() {
        return type;
    }

    public void setType(final byte type) {
        this.type = type;
    }

    public byte getDepth() {
        return depth;
    }

    public void setDepth(final byte depth) {
        this.depth = depth;
    }

    public byte getScope() {
        return scope;
    }

    public void setScope(final byte scope) {
        this.scope = scope;
    }

    public String getOwner() {
        return owner;
    }

    public void setOwner(final String owner) {
        this.owner = owner;
    }

    public long getTimeOut() {
        return timeout;
    }

    public void setTimeOut(final long timeout) {
        this.timeout = timeout;
    }

    public String getOpaqueLockToken() {
        return token;
    }

    public void setOpaqueLockToken(final String token) {
        this.token = token;
    }

    public byte getResourceType() {
        return resourceType;
    }

    public void setResourceType(final byte type) {
        resourceType = type;
    }

    public boolean isNullResource() {
        return (resourceType == LockToken.RESOURCE_TYPE_NULL_RESOURCE);
    }

    // Create new UUID for token
    public void createOpaqueLockToken() {
        token = LockToken.generateUUID();
    }

    // Helper function.
    public static String generateUUID() {
        return UUIDGenerator.getUUID();
    }

    public void write(final VariableByteOutputStream ostream) throws IOException {
        ostream.writeByte(type);
        ostream.writeByte(depth);
        ostream.writeByte(scope);
        ostream.writeUTF(owner != null ? owner : "");
        ostream.writeLong(timeout);
        ostream.writeUTF(token != null ? token : "");
        ostream.writeByte(resourceType);
    }

    public void read(final VariableByteInput istream) throws IOException {
        type = istream.readByte();
        depth = istream.readByte();
        scope = istream.readByte();
        owner = istream.readUTF();
        if(owner.length() == 0) {
            owner = null;
        }
        timeout = istream.readLong();
        token = istream.readUTF();
        if(token.length() == 0) {
            token = null;
        }
        resourceType = istream.readByte();
    }

}