/*
 * Copyright 2012-2015 org.opencloudb.
 *  
 * 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.
 */
package org.opencloudb.server;

import java.io.EOFException;
import java.nio.channels.SocketChannel;
import java.sql.SQLNonTransientException;

import org.apache.log4j.Logger;
import org.opencloudb.MycatServer;
import org.opencloudb.config.ErrorCode;
import org.opencloudb.config.model.SchemaConfig;
import org.opencloudb.net.FrontendConnection;
import org.opencloudb.route.RouteResultset;
import org.opencloudb.route.ServerRouter;
import org.opencloudb.server.response.Heartbeat;
import org.opencloudb.server.response.Ping;
import org.opencloudb.util.TimeUtil;

/**
 * @author mycat
 */
public class ServerConnection extends FrontendConnection {
	private static final Logger LOGGER = Logger
			.getLogger(ServerConnection.class);
	private static final long AUTH_TIMEOUT = 15 * 1000L;

	private volatile int txIsolation;
	private volatile boolean autocommit;
	private volatile boolean txInterrupted;
	private long lastInsertId;
	private NonBlockingSession session;
	protected volatile boolean backReadSupressed = false;

	public ServerConnection(SocketChannel channel) {
		super(channel);
		this.txInterrupted = false;
		this.autocommit = true;
	}

	@Override
	public boolean isIdleTimeout() {
		if (isAuthenticated) {
			return super.isIdleTimeout();
		} else {
			return TimeUtil.currentTimeMillis() > Math.max(lastWriteTime,
					lastReadTime) + AUTH_TIMEOUT;
		}
	}

	public int getTxIsolation() {
		return txIsolation;
	}

	public void setTxIsolation(int txIsolation) {
		this.txIsolation = txIsolation;
	}

	public boolean isAutocommit() {
		return autocommit;
	}

	public void setAutocommit(boolean autocommit) {
		this.autocommit = autocommit;
	}

	public long getLastInsertId() {
		return lastInsertId;
	}

	public void setLastInsertId(long lastInsertId) {
		this.lastInsertId = lastInsertId;
	}

	/**
	 * 设置是否需要中断当前事务
	 */
	public void setTxInterrupt() {
		if (!autocommit && !txInterrupted) {
			txInterrupted = true;
		}
	}

	public NonBlockingSession getSession2() {
		return session;
	}

	public void setSession2(NonBlockingSession session2) {
		this.session = session2;
	}

	@Override
	public void ping() {
		Ping.response(this);
	}

	@Override
	public void heartbeat(byte[] data) {
		Heartbeat.response(this, data);
	}

	public void execute(String sql, int type) {
		// 状态检查
		if (txInterrupted) {
			writeErrMessage(ErrorCode.ER_YES,
					"Transaction error, need to rollback.");
			return;
		}

		// 检查当前使用的DB
		String db = this.schema;
		if (db == null) {
			writeErrMessage(ErrorCode.ER_NO_DB_ERROR, "No database selected");
			return;
		}
		SchemaConfig schema = MycatServer.getInstance().getConfig()
				.getSchemas().get(db);
		if (schema == null) {
			writeErrMessage(ErrorCode.ER_BAD_DB_ERROR, "Unknown database '"
					+ db + "'");
			return;
		}

		// 路由计算
		RouteResultset rrs = null;
		try {

			rrs = ServerRouter.route(schema, type, sql, this.charset, this);
		} catch (SQLNonTransientException e) {
			StringBuilder s = new StringBuilder();
			LOGGER.warn(s.append(this).append(sql).toString(), e);
			String msg = e.getMessage();
			writeErrMessage(ErrorCode.ER_PARSE_ERROR, msg == null ? e
					.getClass().getSimpleName() : msg);
			return;
		}

		// session执行
		session.execute(rrs, type);
	}

	/**
	 * 提交事务
	 */
	public void commit() {
		if (txInterrupted) {
			writeErrMessage(ErrorCode.ER_YES,
					"Transaction error, need to rollback.");
		} else {
			session.commit();
		}
	}

	/**
	 * 回滚事务
	 */
	public void rollback() {
		// 状态检查
		if (txInterrupted) {
			txInterrupted = false;
		}

		// 执行回滚
		session.rollback();
	}

	/**
	 * 撤销执行中的语句
	 * 
	 * @param sponsor
	 *            发起者为null表示是自己
	 */
	public void cancel(final FrontendConnection sponsor) {
		processor.getExecutor().execute(new Runnable() {
			@Override
			public void run() {
				session.cancel(sponsor);
			}
		});
	}

	@Override
	public void error(int errCode, Throwable t) {
		// 根据异常类型和信息，选择日志输出级别。
		if (t instanceof EOFException) {
			if (LOGGER.isDebugEnabled()) {
				LOGGER.debug(toString(), t);
			}
		} else if (isConnectionReset(t)) {
			if (LOGGER.isInfoEnabled()) {
				LOGGER.info(toString(), t);
			}
		} else {
			LOGGER.warn(toString(), t);
		}

		String msg = t.getMessage();
		writeErrMessage(ErrorCode.ER_YES, msg == null ? t.getClass()
				.getSimpleName() : msg);

	}

	@Override
	public void close(String reason) {

		super.close(reason);
		if (this.isClosed()) {
			processor.getExecutor().execute(new Runnable() {
				@Override
				public void run() {
					session.terminate();
				}
			});
			return;
		}
	}

	/**
	 * when front connection write available ,back connections can read more
	 * data to process and send
	 */
	public void writeQueueAvailable() {
		if (backReadSupressed) {
			session.unSupressTargetChannelReadEvent();
			backReadSupressed = false;
		}
	}

	public void writeQueueBlocked() {
		if (!backReadSupressed) {
			session.supressTargetChannelReadEvent();
			backReadSupressed = true;
		}
	}

}