/**

  * SQL-DK

  * Copyright © 2013 František Kučera (frantovo.cz)

  *

  * This program is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, either version 3 of the License, or

  * (at your option) any later version.

  *

  * This program is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

  * GNU General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with this program. If not, see <http://www.gnu.org/licenses/>.

  */

 package info.globalcode.sql.dk;

 import info.globalcode.sql.dk.batch.Batch;

 import info.globalcode.sql.dk.configuration.DatabaseDefinition;

 import info.globalcode.sql.dk.formatting.ColumnsHeader;

 import info.globalcode.sql.dk.formatting.Formatter;

 import java.sql.Connection;

 import java.sql.DriverManager;

 import java.sql.PreparedStatement;

 import java.sql.ResultSet;

 import java.sql.SQLException;

 /**

  *

  * @author Ing. František Kučera (frantovo.cz)

  */

 public class DatabaseConnection {

 	private DatabaseDefinition databaseDefinition;

 	private Connection connection;

 	public DatabaseConnection(DatabaseDefinition databaseDefinition) throws SQLException {

 		this.databaseDefinition = databaseDefinition;

 		connection = DriverManager.getConnection(databaseDefinition.getUrl(), databaseDefinition.getUserName(), databaseDefinition.getPassword());

 	}

 	public void executeQuery(SQLCommand sqlCommand, Formatter formatter) throws SQLException {

 		formatter.writeStartDatabase(databaseDefinition);

 		processCommand(sqlCommand, formatter);

 		formatter.writeEndDatabase();

 	}

 	public void executeBatch(Batch batch, Formatter formatter) throws SQLException {

 		formatter.writeStartDatabase(databaseDefinition);

 		while (batch.hasNext()) {

 			processCommand(batch.next(), formatter);

 		}

 		formatter.writeEndDatabase();

 	}

 	private void processCommand(SQLCommand sqlCommand, Formatter formatter) throws SQLException {

 		SQLCommand.COMMAND_TYPE commandType = sqlCommand.getCommandType();

 		switch (commandType) {

 			case QUERY:

 				processQueryCommand(sqlCommand, formatter);

 				break;

 			case UPDATE:

 				processUpdateCommand(sqlCommand, formatter);

 				break;

 			default:

 				throw new IllegalArgumentException("Unexpected command type: " + commandType);

 		}

 	}

 	private void processQueryCommand(SQLCommand sqlCommand, Formatter formatter) throws SQLException {

 		formatter.writeStartResultSet();

 		formatter.writeQuery(sqlCommand.getQuery());

 		formatter.writeParameters(sqlCommand.getParameters());

 		try (PreparedStatement ps = sqlCommand.prepareStatement(connection)) {

 			sqlCommand.parametrize(ps);

 			boolean isRS = ps.execute();

 			if (isRS) {

 				try (ResultSet rs = ps.getResultSet()) {

 					processResultSet(rs, formatter);

 				}

 			} else {

 				/**

 				 * TODO: process UPDATE command

 				 */

 			}

 			while (ps.getMoreResults() || ps.getUpdateCount() > -1) {

 				/**

 				 * TODO: process more RS or UPDATEs

 				 */

 			}

 		}

 		formatter.writeEndResultSet();

 	}

 	private void processUpdateCommand(SQLCommand sqlCommand, Formatter formatter) throws SQLException {

 		formatter.writeStartUpdatesResult();

 		formatter.writeQuery(sqlCommand.getQuery());

 		formatter.writeParameters(sqlCommand.getParameters());

 		try (PreparedStatement ps = sqlCommand.prepareStatement(connection)) {

 			sqlCommand.parametrize(ps);

 			int updatedRowsCount = ps.executeUpdate();

 			formatter.writeUpdatedRowsCount(updatedRowsCount);

 			formatter.writeStartGeneratedKeys();

 			try (ResultSet rs = ps.getGeneratedKeys()) {

 				processResultSet(rs, formatter);

 			}

 			formatter.writeEndGeneratedKeys();

 		}

 		formatter.writeEndUpdatesResult();

 	}

 	private void processResultSet(ResultSet rs, Formatter formatter) throws SQLException {

 		formatter.writeColumnsHeader(new ColumnsHeader(rs.getMetaData()));

 		int columnCount = rs.getMetaData().getColumnCount();

 		while (rs.next()) {

 			formatter.writeStartRow();

 			for (int i = 1; i <= columnCount; i++) {

 				formatter.writeColumnValue(rs.getObject(i));

 			}

 			formatter.writeEndRow();

 		}

 	}

 }