// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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.

package com.cloud.async.dao;

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.TimeZone;

import javax.ejb.Local;
import javax.inject.Inject;

import org.apache.log4j.Logger;
import org.springframework.stereotype.Component;

import com.cloud.async.SyncQueueItemVO;
import com.cloud.utils.DateUtil;
import com.cloud.utils.db.DB;
import com.cloud.utils.db.Filter;
import com.cloud.utils.db.GenericDaoBase;
import com.cloud.utils.db.GenericSearchBuilder;
import com.cloud.utils.db.SearchBuilder;
import com.cloud.utils.db.SearchCriteria;
import com.cloud.utils.db.SearchCriteria.Op;
import com.cloud.utils.db.Transaction;

@Component
@Local(value = { SyncQueueItemDao.class })
@DB
public class SyncQueueItemDaoImpl extends GenericDaoBase<SyncQueueItemVO, Long> implements SyncQueueItemDao {
    private static final Logger s_logger = Logger.getLogger(SyncQueueItemDaoImpl.class);
    final GenericSearchBuilder<SyncQueueItemVO, Long> queueIdSearch;
    
    protected SyncQueueItemDaoImpl() {
        super();
        queueIdSearch = createSearchBuilder(Long.class);
        queueIdSearch.and("contentId", queueIdSearch.entity().getContentId(), Op.EQ);
        queueIdSearch.and("contentType", queueIdSearch.entity().getContentType(), Op.EQ);
        queueIdSearch.selectField(queueIdSearch.entity().getId());
        queueIdSearch.done();
    }
    

	@Override
	public SyncQueueItemVO getNextQueueItem(long queueId) {
		
		SearchBuilder<SyncQueueItemVO> sb = createSearchBuilder();
        sb.and("queueId", sb.entity().getQueueId(), SearchCriteria.Op.EQ);
        sb.and("lastProcessNumber", sb.entity().getLastProcessNumber(),	SearchCriteria.Op.NULL);
        sb.done();
        
    	SearchCriteria<SyncQueueItemVO> sc = sb.create();
    	sc.setParameters("queueId", queueId);
    	
    	Filter filter = new Filter(SyncQueueItemVO.class, "created", true, 0L, 1L);
        List<SyncQueueItemVO> l = listBy(sc, filter);
        if(l != null && l.size() > 0)
        	return l.get(0);
    	
		return null;
	}

	@Override
	public List<SyncQueueItemVO> getNextQueueItems(int maxItems) {
		List<SyncQueueItemVO> l = new ArrayList<SyncQueueItemVO>();
		
		String sql = "SELECT i.id, i.queue_id, i.content_type, i.content_id, i.created " +
					 " FROM sync_queue AS q JOIN sync_queue_item AS i ON q.id = i.queue_id " +
                     " WHERE q.queue_size < q.queue_size_limit AND i.queue_proc_number IS NULL " +
					 " GROUP BY q.id " +
					 " ORDER BY i.id " +
					 " LIMIT 0, ?";

        Transaction txn = Transaction.currentTxn();
        PreparedStatement pstmt = null;
        try {
            pstmt = txn.prepareAutoCloseStatement(sql);
            pstmt.setInt(1, maxItems);
            ResultSet rs = pstmt.executeQuery();
            while(rs.next()) {
            	SyncQueueItemVO item = new SyncQueueItemVO();
            	item.setId(rs.getLong(1));
            	item.setQueueId(rs.getLong(2));
            	item.setContentType(rs.getString(3));
            	item.setContentId(rs.getLong(4));
            	item.setCreated(DateUtil.parseDateString(TimeZone.getTimeZone("GMT"), rs.getString(5)));
            	l.add(item);
            }
        } catch (SQLException e) {
        	s_logger.error("Unexpected sql excetpion, ", e);
        } catch (Throwable e) {
        	s_logger.error("Unexpected excetpion, ", e);
        }
		return l;
	}
	
	@Override
	public List<SyncQueueItemVO> getActiveQueueItems(Long msid, boolean exclusive) {
		SearchBuilder<SyncQueueItemVO> sb = createSearchBuilder();
        sb.and("lastProcessMsid", sb.entity().getLastProcessMsid(),
    		SearchCriteria.Op.EQ);
        sb.done();
        
    	SearchCriteria<SyncQueueItemVO> sc = sb.create();
    	sc.setParameters("lastProcessMsid", msid);
    	
    	Filter filter = new Filter(SyncQueueItemVO.class, "created", true, null, null);
    	
    	if(exclusive)
    		return lockRows(sc, filter, true);
        return listBy(sc, filter);
	}
	

    @Override
    public List<SyncQueueItemVO> getBlockedQueueItems(long thresholdMs, boolean exclusive) {
        Date cutTime = DateUtil.currentGMTTime();
        
        SearchBuilder<SyncQueueItemVO> sbItem = createSearchBuilder();
        sbItem.and("lastProcessMsid", sbItem.entity().getLastProcessMsid(), SearchCriteria.Op.NNULL);
        sbItem.and("lastProcessNumber", sbItem.entity().getLastProcessNumber(), SearchCriteria.Op.NNULL);
        sbItem.and("lastProcessNumber", sbItem.entity().getLastProcessTime(), SearchCriteria.Op.NNULL);
        sbItem.and("lastProcessTime2", sbItem.entity().getLastProcessTime(), SearchCriteria.Op.LT);
        
        sbItem.done();
        
        SearchCriteria<SyncQueueItemVO> sc = sbItem.create();
        sc.setParameters("lastProcessTime2", new Date(cutTime.getTime() - thresholdMs));
        
        if(exclusive)
            return lockRows(sc, null, true);
        return listBy(sc, null);
    }


    @Override
    public Long getQueueItemIdByContentIdAndType(long contentId, String contentType) {
        SearchCriteria<Long> sc = queueIdSearch.create();
        sc.setParameters("contentId", contentId);
        sc.setParameters("contentType", contentType);
        List<Long> id = customSearch(sc, null);

        return id.size() == 0 ? null : id.get(0);
    }
}