/*
 * (C) 2007-2012 Alibaba Group Holding Limited.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * Authors:
 *   wuhua <wq163@163.com> , boyan <killme2008@gmail.com>
 */
package com.taobao.metamorphosis.tools.query;

import java.util.Collections;
import java.util.List;

import org.I0Itec.zkclient.ZkClient;
import org.I0Itec.zkclient.exception.ZkNoNodeException;
import org.apache.commons.lang.StringUtils;

import com.taobao.metamorphosis.tools.utils.StringUtil;
import com.taobao.metamorphosis.utils.MetaZookeeper;
import com.taobao.metamorphosis.utils.ZkUtils;


/**
 * ��zk�в�ѯclient�˵�offset����
 * 
 * @author pingwei
 */
public class ZkOffsetStorageQuery implements OffsetStorageQuery {

    ZkClient zkClient;
    final MetaZookeeper metaZookeeper;
    final String consumerBasePath;// = ZkUtils.consumersPath + "/";//
                                  // "/meta/consumers/";


    public ZkOffsetStorageQuery(ZkClient zkClient, MetaZookeeper metaZookeeper) {
        this.zkClient = zkClient;
        this.metaZookeeper = metaZookeeper;
        this.consumerBasePath = metaZookeeper.consumersPath + "/";
    }

    public String getOffset(OffsetQueryDO queryDO) {
        if (!this.check(queryDO)) {
            return null;
        }
        String path =
                this.consumerBasePath + queryDO.getGroup() + "/offsets/" + queryDO.getTopic() + "/"
                        + queryDO.getPartition();
        String rt = ZkUtils.readDataMaybeNull(this.zkClient, path);
        return normalizeOffset(rt);
    }

    private String normalizeOffset(String rt) {
        if (rt.indexOf("-") > 0) {
            String[] tmps = rt.split("-");
            if (tmps.length >= 2)
                return tmps[1];
            else
                return tmps[0];
        }
        else
            return rt;
    }


    public static long parseOffsetAsLong(String offsetString) {
        if (StringUtils.isBlank(offsetString)) {
            return -1;
        }

        String[] tmp = StringUtils.splitByWholeSeparator(offsetString, "-");

        try {

            if (tmp != null && tmp.length == 1) {
                return Long.parseLong(offsetString);
            }
            else if ((tmp != null && tmp.length == 2)) {
                return Long.parseLong(tmp[1]);
            }
            else {
                return -1;
            }
        }
        catch (NumberFormatException e) {
            return -1;
        }
    }

    public List<String> getConsumerGroups() {
        return this.zkClient.getChildren(metaZookeeper.consumersPath);
    }

    public List<String> getTopicsExistOffset(String group) {
        try {
            return this.zkClient.getChildren(this.consumerBasePath + group + "/offsets");
        }
        catch (ZkNoNodeException e) {
            return Collections.emptyList();
        }
    }


    public List<String> getPartitionsOf(String group, String topic) {
        return this.zkClient.getChildren(this.consumerBasePath + group + "/offsets/" + topic);
    }

    private boolean check(OffsetQueryDO queryDO) {
        if (queryDO == null) {
            return false;
        }
        if (StringUtil.empty(queryDO.getGroup())) {
            return false;
        }
        if (StringUtil.empty(queryDO.getTopic())) {
            return false;
        }
        if (StringUtil.empty(queryDO.getPartition())) {
            return false;
        }
        return true;
    }

}