package org.gcube.vremanagement.vremodeler.db;


import java.io.File;
import java.rmi.RemoteException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Hashtable;
import org.gcube.common.core.faults.GCUBEFault;
import org.gcube.common.core.utils.logging.GCUBELog;
import org.gcube.vremanagement.vremodeler.impl.ServiceContext;
import org.gcube.vremanagement.vremodeler.impl.util.Listable;

/**
 * 
 * @author lucio
 *
 */
public class DBInterface {
	
	private static Hashtable< String, Connection> connectionMapping= new Hashtable<String, Connection>();
	
	private static String dbFile = ServiceContext.getContext().getPersistenceRoot()+ File.separator + "vreModelerDB"; 
	
	private static GCUBELog logger = new GCUBELog(DBInterface.class);
	/**
	 * 
	 * @return
	 * @throws SQLException
	 */
	
	public static boolean dbAlreadyCreated(){
		File file= new File(dbFile+ServiceContext.getContext().getScope().toString().replace("/", "-")+".data");
		logger.trace("the db "+file.getName()+" exists ?"+ file.exists());
		return file.exists();
	}
	
	public static Connection connect() throws SQLException{
		
		if(connectionMapping.get(ServiceContext.getContext().getScope().toString())==null)
		{
			// Load the HSQL Database Engine JDBC driver
	        // hsqldb.jar should be in the class path or made part of the current jar
	        
			logger.info(dbFile);
			try{
	        	 Class.forName("org.hsqldb.jdbcDriver");
	        }catch(ClassNotFoundException e){throw new SQLException(e.getMessage());}	
	        // connect to the database.   This will load the db files and start the
	        // database if it is not alread running.
	        // db_file_name_prefix is used to open or create files that hold the state
	        // of the db.
	        // It can contain directory names relative to the
	        // current working directory
	        	                
	        Connection conn = DriverManager.getConnection("jdbc:hsqldb:file:"
	                                           + dbFile+ServiceContext.getContext().getScope().toString().replace("/", "-"),    // filenames
	                                           "sa",                     // username
	                                           "");    // password
	        
	        connectionMapping.put(ServiceContext.getContext().getScope().toString(), conn);
	        
		}
		return connectionMapping.get(ServiceContext.getContext().getScope().toString());
		
	}
	
	
	public static Connection getConnection(){
		return connectionMapping.get(ServiceContext.getContext().getScope().toString());
	}
	
	/**
	 * 
	 * @param query
	 */
	public static synchronized void ExecuteUpdate(String query) throws Exception{
		Statement st = null;
        Connection conn= getConnection();
        try{
        	st = conn.createStatement();         // statement objects can be reused with
        	st.executeUpdate(query);
        	st.close();
        }catch(SQLException e){throw e;}
        
	}
	
	
	public  static synchronized   void  insertIntoListable(String table, Listable... values) throws GCUBEFault {

        if (values==null) throw new GCUBEFault();
		Statement st = null;
        
		Connection conn= getConnection();
		
        try{
        	st = conn.createStatement();         // statement objects can be reused with
        }catch(SQLException e){//logger.error("error creating SQL statement");
        	throw new GCUBEFault(e);}
        
        StringBuffer insertQuery;
        
        
        for (Listable row: values)
        {
      	
        	insertQuery=new StringBuffer();
        	insertQuery.append("INSERT INTO ").append(table.toUpperCase()).append(" VALUES(");
        	try{
        		        		
        		
        		for(String value: row.getAsStringList()){
        			insertQuery.append("'").append(value.replaceAll("'", " ")).append("',");
        		}
        		        		        
        		insertQuery.deleteCharAt(insertQuery.length()-1).append(");");
        		logger.trace("Query for inserting in hsqldb "+insertQuery);
        		        	
        		 st.executeUpdate(insertQuery.toString());    // run the query
        	}catch(SQLException e){
        		logger.warn("HSQLDB ERROR: Problem inserting data "+insertQuery,e);
        	   
        	}
        	
        	 catch(Exception e){
        		 logger.error("VDLModelService error: Problem inserting data ",e);
        		 
        	}
        }     
        
        try{
        	st.close();
        }catch(SQLException e){
        	logger.error("error closing SQL statement",e);
        	throw new GCUBEFault(e);}
    }
	

	/**
	 * 
	 * @param table
	 * @param values
	 * @throws RemoteException
	 */
	public static synchronized void insertInto(String table, String[]... rows) throws GCUBEFault {

	   Connection conn= getConnection();
       Statement st = null;
               
       try{
       	st = conn.createStatement();         // statement objects can be reused with
       }catch(SQLException e){//logger.error("error creating SQL statement");
       	throw new GCUBEFault(e);}
       
        
        StringBuffer insertQuery;
        
        for (String[] row: rows)
        {
      	
        	insertQuery=new StringBuffer();
        	insertQuery.append("INSERT INTO ").append(table.toUpperCase()).append(" VALUES(");
        	try{
        		        		
        		for(String value: row){
        			insertQuery.append("'").append(value.replaceAll("'", " ")).append("',");
        		}
        		        		        
        		insertQuery.deleteCharAt(insertQuery.length()-1).append(");");
        		logger.trace("Query for inserting in hsqldb "+insertQuery);
        		        	
        		 st.executeUpdate(insertQuery.toString());    // run the query
        	}catch(SQLException e){
        		logger.warn("HSQLDB ERROR: Problem inserting data "+ insertQuery,e);
        	}
        	
        	 catch(Exception e){
        		 logger.error("VDLModelService error: Problem inserting data ",e);
        	}
        }     
        
        try{
        	st.close();
        }catch(SQLException e){
        	logger.error("error closing SQL statement");
        	throw new GCUBEFault(e);}
    }
	
	
	/**
	 * 
	 * @param query
	 * @return
	 * @throws SQLException
	 */
	public static synchronized ResultSet queryDB(String query) throws SQLException {

        Statement st = null;
        ResultSet rs = null;
        Connection conn= getConnection();
        
        st = conn.createStatement();         // statement objects can be reused with
       
                       
        rs = st.executeQuery(query);    // run the query
                    
        st.close();    
        return rs;
        
    }
	
	
	
	/**
	 * 
	 * @param table
	 * @throws SQLException
	 */
	public static void deleteAll(String table) throws SQLException{
		String query="DELETE FROM "+table.toUpperCase();
		Connection conn= getConnection();
		Statement st=conn.createStatement();
		st.executeUpdate(query);
		st.close();
	}
	
	public static void deleteElement(String table, String whereClause) throws SQLException{
		String query="DELETE FROM "+table.toUpperCase()+" WHERE "+whereClause;
		Connection conn= getConnection();
		Statement st=conn.createStatement();
		st.executeUpdate(query);
		st.close();
	}
	
	public static void close() throws SQLException{
		Connection conn= getConnection();
		if (conn!=null){
			conn.close();
			conn=null;
		}
	}
		
}