/*
 *   Copyright 2011 Brian Rosenberger (Brutex Network)
 *
 *   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 net.brutex.xservices.util;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;


import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.quartz.utils.ConnectionProvider;

/**
 * @author Brian Rosenberger
 * 
 */
public class BrutexHSQLQuartzConnectionProvider implements ConnectionProvider {
	
	private Connection conn = null;
	private final Logger logger = Logger.getLogger(this.getClass().getCanonicalName());
	

	public Connection getConnection() throws SQLException {
		if( conn!= null ) { // Todo: && conn.conn.isValid(5)) {
			logger.debug("Checking tables on pre-exisiting database connection.");
			checkTables();
			return conn;
		}
		try {
			// Class.forName("org.hsqldb.jdbc.JDBCDriver" );
			Class.forName("org.apache.derby.jdbc.EmbeddedDriver");
		} catch (Exception e) {
			logger.fatal("Failed to load Derby JDBC driver.");
			e.printStackTrace();
			return null;
		}

		if(isConnected(false)) {
			checkTables();
		} else {
			return null;
		}
		
		return conn;
	}

	public void shutdown() throws SQLException {
		try {
			// Class.forName("org.hsqldb.jdbc.JDBCDriver" );
			Class.forName("org.apache.derby.jdbc.EmbeddedDriver");
		} catch (Exception e) {
			System.err.println("ERROR: failed to load Derby JDBC driver.");
			e.printStackTrace();
			return;
		}
		String t = this.getClass().getClassLoader().getResource("/").toString()
				.substring(6);
		t += "../data/db";
		System.out.println("Shut down embedded database now.");
		Connection c = DriverManager.getConnection("jdbc:derby:" + t
				+ ";shutdown=true;");

	}

	private synchronized void recursiveDelete(File dbDir) {
		File[] files = dbDir.listFiles();
		for (int i = 0; i < files.length; i++) {
			if (files[i].isFile()) {
				files[i].delete();
			} else {
				recursiveDelete(files[i]);
				files[i].delete();
			}
		}
		dbDir.delete();
	}
	
	private synchronized void checkTables() throws SQLException {
		logger.debug("Checking QUARTZ database schema.");
		if(!isConnected(false)) {
			logger.error("Failed to validate QUARTZ database schema.");
			return;
		}
		List<String> ddl_list = new ArrayList<String>(11);
		ddl_list.add("QRTZ_JOB_DETAILS");
		ddl_list.add("QRTZ_TRIGGERS");
		ddl_list.add("QRTZ_SIMPLE_TRIGGERS");
		ddl_list.add("QRTZ_CRON_TRIGGERS");
		ddl_list.add("QRTZ_SIMPROP_TRIGGERS");
		ddl_list.add("QRTZ_BLOB_TRIGGERS");
		ddl_list.add("QRTZ_CALENDARS");
		ddl_list.add("QRTZ_PAUSED_TRIGGER_GRPS");
		ddl_list.add("QRTZ_FIRED_TRIGGERS");
		ddl_list.add("QRTZ_SCHEDULER_STATE");
		ddl_list.add("QRTZ_LOCKS");
		
		String ddl = this.getClass().getClassLoader().getResource("/").toString()
		.substring(6)+ "../data/";

		DatabaseMetaData dmd = conn.getMetaData();
		for (String tbl : ddl_list) {
			ResultSet rs = dmd.getTables(null, "APP", tbl, null);
			if (!rs.next()) {
				logger.log(Level.INFO, "Adding DDL for table "+ tbl);
				Statement st = conn.createStatement();
				File ddlFile = new File(ddl + tbl + ".ddl");
				String create = "";
				try {
						BufferedReader r = new BufferedReader(new FileReader(ddlFile));
						while (r.ready()) {
							create += r.readLine() + "\n";
						}
						create.trim();
						if( st.execute(create)) {
							logger.log(Level.INFO, "Table " + tbl + " created.");
						} 
					} catch (FileNotFoundException ex) {
						ex.printStackTrace();
					} catch (IOException ex) {
						ex.printStackTrace();
					} catch (SQLException ex) {
						logger.log(Level.ERROR, "Error executing statement "+ create );
						System.out.println(ex.getMessage());
					}
				} else {
					logger.trace("Table "+tbl+" exists.");
				}
			}
		}
	
	private synchronized boolean isConnected(boolean fail) throws SQLException {
		if(conn!=null ) { // Todo: && conn.conn.isValid(5)) {) {
			return true;
		} else {
			String t = this.getClass().getClassLoader().getResource("/").toString().substring(6); // WEB-INF/classes
			t += "../data/db";
			logger.debug("Database directory is set to '" + t + "'");
			try {
				this.conn = DriverManager.getConnection("jdbc:derby:" + t + ";create=true;");
			} catch (SQLException ex) {
				logger.error(ex.getMessage(), ex);
				if(!fail) {
					logger.warn("Deleting database directory.");
					recursiveDelete(new File(t));
					logger.warn("Retrying to connect to database.");
					return isConnected(true);
				} else {
					return false;
				}
			}
		}
		return false;
	}

	@Override
	public void initialize() throws SQLException {
		// TODO Auto-generated method stub
		
	}
}