/*
 * Author: Joseph Wang
 */
package com.leadpoint.syndication.db.mongo.mortgage;

import java.util.ArrayList;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.leadpoint.config.Meta;
import com.leadpoint.db.Tuple;
import com.leadpoint.syndication.common.Constants;
import com.leadpoint.syndication.common.mortgage.BaseTableRow;
import com.leadpoint.syndication.db.mongo.mortgage.MongoConnnection;
import com.mongodb.BasicDBObject;
import com.mongodb.Bytes;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.Mongo;

public class BaseTableQueryEngine {
	private static Meta META = Meta.getMeta(BaseTableQueryEngine.class);
	private static boolean enable_debug = META
			.getBoolean("enable_debug", false);
	protected BasicDBObject dbQuery;
	protected String currentDb = Constants.BLANK_STRING;
	protected String currentCollection = Constants.BLANK_STRING;
	protected boolean success = true;
	private static Log log = LogFactory.getLog(BaseTableQueryEngine.class);

	protected BaseTableQueryEngine(Map<String, String> args) {

	}

	public boolean isSuccess() {
		return success;
	}

	public void setSuccess(boolean success) {
		this.success = success;
	}

	protected ArrayList<Tuple> fetch(int timeout) {
		ArrayList<Tuple> tuples = new ArrayList<Tuple>(200);

		try {
			Mongo mongo = MongoConnnection.getInstance().getMongo();
			long fStart = System.currentTimeMillis();

			if (mongo != null) {
				DB db = mongo.getDB(currentDb);

				if (enable_debug) {
					log.debug("BaseTableQueryEngine: Connected to db "
							+ currentDb + " collection " + currentCollection);
				}

				if (db != null) {
					DBCollection coll = db.getCollection(currentCollection);
					DBCursor cur = null;

					cur = coll.find(dbQuery).addOption(
							Bytes.QUERYOPTION_SLAVEOK);
					
					DBObject dbObject = db.getLastError();
					if (dbObject != null && dbObject.get("err") != null) {
						log.warn("BaseTableQueryEngine: Encounter error for query " + dbQuery.toString());
						setSuccess(false);
					}

					if (enable_debug) {
						log.debug("BaseTableQueryEngine: Run query "
								+ dbQuery.toString());
						log.debug("BaseTableQueryEngine: Found "
								+ cur.count() + " in "
								+ (System.currentTimeMillis() - fStart));
					}
					while (cur.hasNext()) {
						BasicDBObject dbo = (BasicDBObject) cur.next();
						BaseTableRow row = new BaseTableRow(dbo);
						if (row.isValid()) {
							tuples.add(row.getTuple());
						}

						long time = (timeout - (System.currentTimeMillis() - fStart));
						if (time < 0) {
							break;
						}
					}

					if (enable_debug) {
						log.debug("BaseTableQueryEngine: tuples "
								+ tuples.size() + " in time "
								+ (System.currentTimeMillis() - fStart));
					}
				}
			} else {
				log.info("BaseTableQueryEngine: reconnect MongoDB");
				MongoConnnection.getInstance().reconnect();
			}
		} catch (Exception ex) {
			log.error("BaseTableQueryEngine: exception " + ex);
			ex.printStackTrace();
			setSuccess(false);
		}

		return tuples;
	}

	public ArrayList<Tuple> execute(int timeout) {
		long fStart = System.currentTimeMillis();
		ArrayList<Tuple> tuples = fetch(timeout);
		long time = (timeout - (System.currentTimeMillis() - fStart));

		if ((tuples == null || !isSuccess()) && time > 0) {
			ArrayList<Tuple> tuples2 = fetch((int) time);

			if (tuples2 != null
					&& (tuples == null || tuples.size() < tuples2.size())) {
				return tuples2;
			}
		}

		return tuples;
	}
}