/*
 * SSSync, a Simple and Stupid Synchronizer for data with multi-valued attributes
 * Copyright (C) 2014  Ludovic Pouzenc <ludovic@pouzenc.fr>
 *  
 * This file is part of SSSync.
 *
 *  SSSync 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.
 *
 *  SSSync 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 SSSync.  If not, see <http://www.gnu.org/licenses/>
 */

package data.io.sql;

import java.io.Closeable;
import java.io.File;
import java.io.IOException;
import java.sql.Connection;
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.SQLException;

import data.io.MVDataReader;

/**
 * TODO javadoc
 * 
 * @author lpouzenc
 */
public class SQLConnectionWrapper implements Closeable {

	/**
	 * Enumeration of supported DBMS. Each use a particular JDBC driver.
	 */
	public enum DBMSType { ORACLE, MYSQL }

	private final Connection conn;
	
	/**
	 * TODO javadoc
	 * @param dbms
	 * @param host
	 * @param port
	 * @param ress
	 * @param user
	 * @param pass
	 * @param db
	 */
	public SQLConnectionWrapper(DBMSType dbms, String host, int port, String ress, String user, String pass, String db) {
		
		String driverClassName=null;
		String url;
		
		switch ( dbms ) {
		case ORACLE:
			driverClassName="oracle.jdbc.driver.OracleDriver";
			url="jdbc:oracle:thin:@" + host + ":" + port + ":" + ress + "/" + db;
			break;
		case MYSQL:
			driverClassName="com.mysql.jdbc.Driver";
			url="jdbc:mysql://" + host + ":" + port + "/" + db;
			break;
		/*	Could be useful with JUnit tests
			case derby:
			driverClassName="org.apache.derby.jdbc.EmbeddedDriver";
			url="jdbc:derby:" + db;
			break;
		*/
		default:
			throw new IllegalArgumentException("Unsupported DBMSType : " + dbms); 
		}
		
		try {
			@SuppressWarnings("unchecked")
			Class<? extends Driver> clazz = (Class<? extends Driver>) Class.forName(driverClassName);
			DriverManager.registerDriver(clazz.newInstance());
		} catch (Exception e) {
			throw new RuntimeException("Can't load or register JDBC driver for " + dbms + " (" + driverClassName + ")", e);
		}
		
		try {
			conn = DriverManager.getConnection(url, user, pass);
		} catch (SQLException e) {
			throw new RuntimeException("Can't establish database connection (" + url + ")");
		}
	}

	/**
	 * Builds a new reader against current connection and a File containing a SELECT statement.
	 * @param name
	 * @param queryFile
	 * @return
	 * @throws IOException 
	 */
	public MVDataReader newReader(String name, File queryFile) throws IOException {
		return new SQLRelDataReader(name, conn, queryFile);
	}

	/**
	 * Builds a new reader against current connection and a String containing a SELECT statement.
	 * @param name
	 * @param query
	 * @return
	 * @throws IOException 
	 */
	public MVDataReader newReader(String name, String query) {
		return new SQLRelDataReader(name, conn, query);
	}
	
	/**
	 * Close the current database connection.
	 */
	@Override
	public void close() throws IOException {
		try {
			conn.close();
		} catch (SQLException e) {
			throw new IOException("Exception occured while trying to close the SQL connection", e);
		}
	}
	
	/**
	 * @return the current database connection (useful for JUnit tests)
	 */
	public Connection getConn() {
		return conn;
	}
}