/*
 *  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.external;

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 java.sql.Connection;
import java.sql.SQLException;

public class ExternalTransaction implements Transaction {

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

  private DataSource dataSource;
  private boolean defaultAutoCommit;
  private boolean setAutoCommitAllowed;
  private Connection connection;
  private IsolationLevel isolationLevel = new IsolationLevel();

  public ExternalTransaction(DataSource ds, boolean defaultAutoCommit, boolean setAutoCommitAllowed, int isolationLevel) throws TransactionException {
    // Check Parameters
    dataSource = ds;
    if (dataSource == null) {
      throw new TransactionException("ExternalTransaction initialization failed.  DataSource was null.");
    }

    this.defaultAutoCommit = defaultAutoCommit;
    this.setAutoCommitAllowed = setAutoCommitAllowed;
    this.isolationLevel.setIsolationLevel(isolationLevel);
  }

  private void init() throws SQLException, TransactionException {
    // Open JDBC Transaction
    connection = dataSource.getConnection();
    if (connection == null) {
      throw new TransactionException("ExternalTransaction could not start transaction.  Cause: The DataSource returned a null connection.");
    }
    // Isolation Level
    isolationLevel.applyIsolationLevel(connection);
    // AutoCommit
    if (setAutoCommitAllowed) {
      if (connection.getAutoCommit() != defaultAutoCommit) {
        connection.setAutoCommit(defaultAutoCommit);
      }
    }
    // Debug
    if (connectionLog.isDebugEnabled()) {
      connection = ConnectionLogProxy.newInstance(connection);
    }
  }

  public void commit() throws SQLException, TransactionException {
  }

  public void rollback() throws SQLException, TransactionException {
  }

  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;
  }

}