/**

 * 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);

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

				processResultSet(rs, formatter);

			}

		}

		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();

		}

	}

}