/**
 * 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();
		}

	}
}