/*
 *  Copyright 2004 Clinton Begin
 *
 *  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 com.ibatis.sqlmap.engine.transaction.jta;

import com.ibatis.common.jdbc.logging.ConnectionLogProxy;
import com.ibatis.common.logging.Log;
import com.ibatis.common.logging.LogFactory;
import com.ibatis.sqlmap.engine.transaction.IsolationLevel;
import com.ibatis.sqlmap.engine.transaction.Transaction;
import com.ibatis.sqlmap.engine.transaction.TransactionException;

import javax.sql.DataSource;
import javax.transaction.Status;
import javax.transaction.UserTransaction;
import java.sql.Connection;
import java.sql.SQLException;

public class JtaTransaction implements Transaction {

  private static final Log connectionLog = LogFactory.getLog(Connection.class);

  private UserTransaction userTransaction;
  private DataSource dataSource;
  private Connection connection;
  private IsolationLevel isolationLevel = new IsolationLevel();

  private boolean commmitted = false;
  private boolean newTransaction = false;

  public JtaTransaction(UserTransaction utx, DataSource ds, int isolationLevel) throws TransactionException {
    // Check parameters
    userTransaction = utx;
    dataSource = ds;
    if (userTransaction == null) {
      throw new TransactionException("JtaTransaction initialization failed.  UserTransaction was null.");
    }
    if (dataSource == null) {
      throw new TransactionException("JtaTransaction initialization failed.  DataSource was null.");
    }
    this.isolationLevel.setIsolationLevel(isolationLevel);
  }

  private void init() throws TransactionException, SQLException {
    // Start JTA Transaction
    try {
      newTransaction = userTransaction.getStatus() == Status.STATUS_NO_TRANSACTION;
      if (newTransaction) {
        userTransaction.begin();
      }
    } catch (Exception e) {
      throw new TransactionException("JtaTransaction could not start transaction.  Cause: ", e);
    }

    // Open JDBC Connection
    connection = dataSource.getConnection();
    if (connection == null) {
      throw new TransactionException("JtaTransaction could not start transaction.  Cause: The DataSource returned a null connection.");
    }
    // Isolation Level
    isolationLevel.applyIsolationLevel(connection);
    // AutoCommit
    if (connection.getAutoCommit()) {
      connection.setAutoCommit(false);
    }
    // Debug
    if (connectionLog.isDebugEnabled()) {
      connection = ConnectionLogProxy.newInstance(connection);
    }
  }

  public void commit() throws SQLException, TransactionException {
    if (connection != null) {
      if (commmitted) {
        throw new TransactionException("JtaTransaction could not commit because this transaction has already been committed.");
      }
      try {
        if (newTransaction) {
          userTransaction.commit();
        }
      } catch (Exception e) {
        throw new TransactionException("JtaTransaction could not commit.  Cause: ", e);
      }
      commmitted = true;
    }
  }

  public void rollback() throws SQLException, TransactionException {
    if (connection != null) {
      if (!commmitted) {
        try {
          if (userTransaction != null) {
            if (newTransaction) {
              userTransaction.rollback();
            } else {
              userTransaction.setRollbackOnly();
            }
          }
        } catch (Exception e) {
          throw new TransactionException("JtaTransaction could not rollback.  Cause: ", e);
        }
      }
    }
  }

  public void close() throws SQLException, TransactionException {
    if (connection != null) {
      try {
        isolationLevel.restoreIsolationLevel(connection);
      } finally {
        connection.close();
        connection = null;
      }
    }
  }

  public Connection getConnection() throws SQLException, TransactionException {
    if (connection == null) {
      init();
    }
    return connection;
  }


}