/*
 * JBoss, Home of Professional Open Source.
 * See the COPYRIGHT.txt file distributed with this work for information
 * regarding copyright ownership.  Some portions may be licensed
 * to Red Hat, Inc. under one or more contributor license agreements.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA.
 */

package org.teiid.translator.jdbc.hana;

import static org.teiid.translator.TypeFacility.RUNTIME_NAMES.*;

import java.sql.Connection;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import org.teiid.language.*;
import org.teiid.language.SQLConstants.NonReserved;
import org.teiid.metadata.MetadataFactory;
import org.teiid.translator.ExecutionContext;
import org.teiid.translator.MetadataProcessor;
import org.teiid.translator.SourceSystemFunctions;
import org.teiid.translator.Translator;
import org.teiid.translator.TranslatorException;
import org.teiid.translator.TypeFacility;
import org.teiid.translator.jdbc.AliasModifier;
import org.teiid.translator.jdbc.ConvertModifier;
import org.teiid.translator.jdbc.FunctionModifier;
import org.teiid.translator.jdbc.JDBCExecutionFactory;
import org.teiid.translator.jdbc.LocateFunctionModifier;
import org.teiid.translator.jdbc.SQLConversionVisitor;
import org.teiid.translator.jdbc.TemplateFunctionModifier;
import org.teiid.util.Version;

@Translator(name = "hana", description = "SAP HANA translator")
public class HanaExecutionFactory extends JDBCExecutionFactory {
	
	private static final String TINYINT_TYPE = "tinyint"; //$NON-NLS-1$

	public static final Version SPS8 = Version.getVersion("SPS8"); //$NON-NLS-1$
	
	private static final String TIME_FORMAT = "HH24:MI:SS"; //$NON-NLS-1$
	private static final String DATE_FORMAT = "YYYY-MM-DD"; //$NON-NLS-1$
	private static final String DATETIME_FORMAT = DATE_FORMAT + " " + TIME_FORMAT; //$NON-NLS-1$
//	private static final String TIMESTAMP_FORMAT = DATETIME_FORMAT + ".FF7";  //$NON-NLS-1$
	
	/*
	 * Date/Time Pushdown Functions 
	 */
	public static final String HANA = "hana"; //$NON-NLS-1$
	public static final String ADD_DAYS = "add_days"; //$NON-NLS-1$
	public static final String ADD_SECONDS = "add_seconds"; //$NON-NLS-1$
	public static final String ADD_WORKDAYS = "add_workdays"; //$NON-NLS-1$
	public static final String ADD_MONTHS = "add_months"; //$NON-NLS-1$
	public static final String ADD_YEARS = "add_years"; //$NON-NLS-1$
	public static final String CURRENT_UTCDATE = "current_utcdate"; //$NON-NLS-1$
	public static final String CURRENT_UTCTIME = "current_utctime"; //$NON-NLS-1$
	public static final String CURRENT_UTCTIMESTAMP = "current_utctimestamp"; //$NON-NLS-1$
	public static final String DAYS_BETWEEN = "days_between"; //$NON-NLS-1$
	public static final String EXTRACT = "extract"; //$NON-NLS-1$
	public static final String ISOWEEK = "isoweek"; //$NON-NLS-1$
	public static final String LAST_DAY = "last_day"; //$NON-NLS-1$
	public static final String LOCALTOUTC = "localtoutc"; //$NON-NLS-1$
	public static final String NANO100_BETWEEN = "nano100_between"; //$NON-NLS-1$
	public static final String NEXT_DAY = "next_day"; //$NON-NLS-1$
	public static final String SECONDS_BETWEEN = "seconds_between"; //$NON-NLS-1$
	public static final String WEEKDAY = "weekday"; //$NON-NLS-1$
	public static final String WORKDAYS_BETWEEN = "weekdays_between"; //$NON-NLS-1$
	
	/*
	 * Numeric Pushdown Functions 
	 */
	public static final String COSH = "cosh"; //$NON-NLS-1$
	public static final String BITSET = "bitset"; //$NON-NLS-1$
	public static final String BITUNSET = "bitunset"; //$NON-NLS-1$
	public static final String HEXTOBIN = "hextobin"; //$NON-NLS-1$
	public static final String RAND = "rand"; //$NON-NLS-1$
	public static final String SINH = "sinh"; //$NON-NLS-1$
	public static final String TANH = "tanh"; //$NON-NLS-1$
	public static final String UMINUS = "uminus"; //$NON-NLS-1$
	
	public HanaExecutionFactory() {
	}

	@Override
	public void start() throws TranslatorException {
		super.start();
		
		registerFunctionModifier(SourceSystemFunctions.LCASE, new AliasModifier("lower")); //$NON-NLS-1$ 
		registerFunctionModifier(SourceSystemFunctions.CEILING, new AliasModifier("ceil")); //$NON-NLS-1$ 
        registerFunctionModifier(SourceSystemFunctions.LCASE, new AliasModifier("lower")); //$NON-NLS-1$ 
        registerFunctionModifier(SourceSystemFunctions.CHAR, new AliasModifier("to_nvarchar")); //$NON-NLS-1$ 
        registerFunctionModifier(SourceSystemFunctions.UCASE, new AliasModifier("upper")); //$NON-NLS-1$ 
        registerFunctionModifier(SourceSystemFunctions.LOG, new Log10FunctionModifier(getLanguageFactory()));
        registerFunctionModifier(SourceSystemFunctions.CEILING, new AliasModifier("ceil")); //$NON-NLS-1$ 
        registerFunctionModifier(SourceSystemFunctions.LOG10, new Log10FunctionModifier(getLanguageFactory())); 
        registerFunctionModifier(SourceSystemFunctions.LOCATE, new LocateFunctionModifier(getLanguageFactory(), "locate", true) { //$NON-NLS-1$

			@Override
			public void modify(Function function) {
				super.modify(function);
				//If a start index was passed in, we convert to a substring on the search string since
				//HANA does not support the start index parameter in LOCATE().
				List<Expression> args = function.getParameters();
				if (args.size() > 2) {
		        	List<Expression> substringArgs = new ArrayList<Expression>();
		            substringArgs.add(args.get(0));
		            substringArgs.add(args.get(2));
		            args.set(0, getLanguageFactory().createFunction(SourceSystemFunctions.SUBSTRING, substringArgs, null));
		            args.remove(2);
		        }
				
			}
        	
    	});
        registerFunctionModifier(SourceSystemFunctions.CURDATE, new AliasModifier("current_date")); //$NON-NLS-1$ 
        registerFunctionModifier(SourceSystemFunctions.CURTIME, new AliasModifier("current_time")); //$NON-NLS-1$
        registerFunctionModifier(SourceSystemFunctions.WEEK, new TemplateFunctionModifier("cast(substring(isoweek(",0,"), 7, 2) as integer)")); //$NON-NLS-1$ //$NON-NLS-2$
        registerFunctionModifier(SourceSystemFunctions.DAYOFWEEK, new TemplateFunctionModifier("(MOD((WEEKDAY(",0,")+1),7)+1)")); //$NON-NLS-1$ //$NON-NLS-2$
        registerFunctionModifier(SourceSystemFunctions.DAYNAME, new TemplateFunctionModifier("initcap(lower(dayname(", 0, ")))")); //$NON-NLS-1$ //$NON-NLS-2$
        registerFunctionModifier(SourceSystemFunctions.QUARTER, new TemplateFunctionModifier("((month(",0,")+2)/3)")); //$NON-NLS-1$ //$NON-NLS-2$
        registerFunctionModifier(SourceSystemFunctions.NOW, new AliasModifier("current_timestamp")); //$NON-NLS-1$ 
        
        //spatial functions
        registerFunctionModifier(SourceSystemFunctions.ST_ASEWKT, new HanaSpatialFunctionModifier());
        registerFunctionModifier(SourceSystemFunctions.ST_ASBINARY, new HanaSpatialFunctionModifier());
        registerFunctionModifier(SourceSystemFunctions.ST_ASGEOJSON, new HanaSpatialFunctionModifier());
        registerFunctionModifier(SourceSystemFunctions.ST_ASTEXT, new HanaSpatialFunctionModifier());
        registerFunctionModifier(SourceSystemFunctions.ST_CONTAINS, new HanaSpatialFunctionModifier());
        registerFunctionModifier(SourceSystemFunctions.ST_CROSSES, new HanaSpatialFunctionModifier());
        registerFunctionModifier(SourceSystemFunctions.ST_DISTANCE, new HanaSpatialFunctionModifier());
        registerFunctionModifier(SourceSystemFunctions.ST_DISJOINT, new HanaSpatialFunctionModifier());
        registerFunctionModifier(SourceSystemFunctions.ST_EQUALS, new HanaSpatialFunctionModifier());
        registerFunctionModifier(SourceSystemFunctions.ST_INTERSECTS, new HanaSpatialFunctionModifier());
        registerFunctionModifier(SourceSystemFunctions.ST_SRID, new HanaSpatialFunctionModifier());
        registerFunctionModifier(SourceSystemFunctions.ST_GEOMFROMTEXT, new HanaSpatialFunctionModifier());
        registerFunctionModifier(SourceSystemFunctions.ST_OVERLAPS, new HanaSpatialFunctionModifier());
        registerFunctionModifier(SourceSystemFunctions.ST_TOUCHES, new HanaSpatialFunctionModifier());
        
          
		//////////////////////////////////////////////////////////
		//TYPE CONVERION MODIFIERS////////////////////////////////
		//////////////////////////////////////////////////////////
        ConvertModifier convertModifier = new ConvertModifier();
        convertModifier.addTypeMapping("boolean", FunctionModifier.BOOLEAN); //$NON-NLS-1$
        convertModifier.addTypeMapping(TINYINT_TYPE, FunctionModifier.BYTE);
        convertModifier.addTypeMapping("smallint", FunctionModifier.SHORT); //$NON-NLS-1$
        convertModifier.addTypeMapping("integer", FunctionModifier.INTEGER); //$NON-NLS-1$
        convertModifier.addTypeMapping("bigint", FunctionModifier.LONG, FunctionModifier.BIGINTEGER); //$NON-NLS-1$
        //convertModifier.addTypeMapping("smalldecimal", FunctionModifier.FLOAT); //$NON-NLS-1$
        convertModifier.addTypeMapping("decimal", FunctionModifier.BIGDECIMAL); //$NON-NLS-1$
        convertModifier.addTypeMapping("float", FunctionModifier.FLOAT); //$NON-NLS-1$
        //convertModifier.addTypeMapping("real", FunctionModifier.FLOAT); //$NON-NLS-1$
        convertModifier.addTypeMapping("date", FunctionModifier.DATE); //$NON-NLS-1$
    	convertModifier.addTypeMapping("double", FunctionModifier.DOUBLE); //$NON-NLS-1$
    	convertModifier.addTypeMapping("time", FunctionModifier.TIME); //$NON-NLS-1$
    	convertModifier.addTypeMapping("timestamp", FunctionModifier.TIMESTAMP); //$NON-NLS-1$
    	//convertModifier.addTypeMapping("seconddate", FunctionModifier.TIMESTAMP); //$NON-NLS-1$
    	convertModifier.addTypeMapping("nvarchar", FunctionModifier.STRING); //$NON-NLS-1$
    	convertModifier.addTypeMapping("nvarchar(1)", FunctionModifier.CHAR); //$NON-NLS-1$
    	//convertModifier.addTypeMapping("alphanum", FunctionModifier.STRING); //$NON-NLS-1$
    	convertModifier.addTypeMapping("varbinary", FunctionModifier.VARBINARY); //$NON-NLS-1$
    	convertModifier.addTypeMapping("blob", FunctionModifier.BLOB); //$NON-NLS-1$
    	convertModifier.addTypeMapping("nclob", FunctionModifier.CLOB); //$NON-NLS-1$
    	convertModifier.addTypeMapping("text", FunctionModifier.XML); //$NON-NLS-1$
    	//convertModifier.addTypeMapping("shorttext", FunctionModifier.STRING); //$NON-NLS-1$
    	convertModifier.addTypeMapping("st_geometry", FunctionModifier.GEOMETRY); //$NON-NLS-1$

    	convertModifier.addConvert(FunctionModifier.STRING, FunctionModifier.DATE, new ConvertModifier.FormatModifier("to_date", DATE_FORMAT)); //$NON-NLS-1$ 
    	convertModifier.addConvert(FunctionModifier.STRING, FunctionModifier.TIME, new ConvertModifier.FormatModifier("to_time", TIME_FORMAT)); //$NON-NLS-1$ 
        convertModifier.addConvert(FunctionModifier.STRING, FunctionModifier.TIMESTAMP, new ConvertModifier.FormatModifier("to_timestamp", DATETIME_FORMAT));  //$NON-NLS-1$ 
        
    	convertModifier.setWideningNumericImplicit(true);
    	convertModifier.addConvert(FunctionModifier.BOOLEAN, FunctionModifier.STRING, new FunctionModifier() {
			@Override
			public List<?> translate(Function function) {
				Expression trueValue = function.getParameters().get(0);
				Expression falseValue = trueValue;
				falseValue = new IsNull(falseValue, true);
				if (!(trueValue instanceof Predicate)) {
					trueValue = new Comparison(trueValue, new Literal(Boolean.TRUE, TypeFacility.RUNTIME_TYPES.BOOLEAN), Comparison.Operator.EQ);
				}
				return Arrays.asList("CASE WHEN ", trueValue, " THEN 'true' WHEN ", falseValue, " THEN 'false' END"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
			}
		});
    	convertModifier.addSourceConversion(new FunctionModifier() {
			@Override
			public List<?> translate(Function function) {
				((Literal)function.getParameters().get(1)).setValue(TINYINT_TYPE);
				return null;
			}
		}, FunctionModifier.BOOLEAN);
    	registerFunctionModifier(SourceSystemFunctions.CONVERT, convertModifier);
    	
    	/*
    	 * Date/Time Pushdown functions
    	 */
    	addPushDownFunction(HANA, ADD_DAYS, DATE, DATE, INTEGER);
    	addPushDownFunction(HANA, ADD_MONTHS, DATE, DATE, INTEGER);
    	addPushDownFunction(HANA, ADD_SECONDS, TIMESTAMP, TIMESTAMP, INTEGER);
    	addPushDownFunction(HANA, ADD_WORKDAYS, DATE, DATE, INTEGER);
    	addPushDownFunction(HANA, ADD_YEARS, DATE, DATE, INTEGER);
    	addPushDownFunction(HANA, CURRENT_UTCDATE, DATE);
    	addPushDownFunction(HANA, CURRENT_UTCTIME, TIME);
    	addPushDownFunction(HANA, CURRENT_UTCTIMESTAMP, TIMESTAMP);
    	addPushDownFunction(HANA, DAYS_BETWEEN, INTEGER, DATE, DATE);
    	addPushDownFunction(HANA, ISOWEEK, STRING, DATE);
    	addPushDownFunction(HANA, LAST_DAY, DATE, DATE);
    	addPushDownFunction(HANA, LOCALTOUTC, TIMESTAMP, TIMESTAMP, STRING);
    	addPushDownFunction(HANA, NANO100_BETWEEN, INTEGER, DATE, DATE);
    	addPushDownFunction(HANA, NEXT_DAY, DATE, DATE);
    	addPushDownFunction(HANA, SECONDS_BETWEEN, INTEGER, DATE, DATE);
    	addPushDownFunction(HANA, WEEKDAY, INTEGER, DATE);
    	addPushDownFunction(HANA, WORKDAYS_BETWEEN, DATE, INTEGER);
    	
    	/*
    	 * Numeric Pushdown functions
    	 */
    	addPushDownFunction(HANA, COSH, INTEGER, FLOAT);
    	addPushDownFunction(HANA, BITSET, STRING, VARBINARY, INTEGER, INTEGER);
    	addPushDownFunction(HANA, BITUNSET, STRING, VARBINARY, INTEGER, INTEGER);
    	addPushDownFunction(HANA, COSH, FLOAT, FLOAT);
    	addPushDownFunction(HANA, HEXTOBIN, BLOB, STRING);
    	addPushDownFunction(HANA, RAND, BLOB);
    	addPushDownFunction(HANA, SINH, FLOAT, FLOAT);
    	addPushDownFunction(HANA, TANH, FLOAT, FLOAT);
    	addPushDownFunction(HANA, UMINUS, INTEGER, INTEGER);
    	
	}
	
	@Override
	public String getHibernateDialectClassName() {
		return "org.hibernate.dialect.HANARowStoreDialect"; //$NON-NLS-1$
	}
	
	@Override
	public List<String> getSupportedFunctions() {
		List<String> supportedFunctions = new ArrayList<String>();
		supportedFunctions.addAll(super.getSupportedFunctions());

		//////////////////////////////////////////////////////////
		//STRING FUNCTIONS////////////////////////////////////////
		//////////////////////////////////////////////////////////
		supportedFunctions.add(SourceSystemFunctions.ASCII);// taken care with alias function modifier
		supportedFunctions.add(SourceSystemFunctions.CHAR);
		supportedFunctions.add(SourceSystemFunctions.CONCAT); 
		supportedFunctions.add(SourceSystemFunctions.LCASE);//ALIAS 'lower'
		supportedFunctions.add(SourceSystemFunctions.LPAD);
		supportedFunctions.add(SourceSystemFunctions.LENGTH);
		supportedFunctions.add(SourceSystemFunctions.LOCATE); 
		supportedFunctions.add(SourceSystemFunctions.LTRIM);
		supportedFunctions.add(SourceSystemFunctions.REPLACE);
		supportedFunctions.add(SourceSystemFunctions.LEFT);
		supportedFunctions.add(SourceSystemFunctions.RIGHT);
		supportedFunctions.add(SourceSystemFunctions.RPAD);
		supportedFunctions.add(SourceSystemFunctions.RTRIM);
		supportedFunctions.add(SourceSystemFunctions.SUBSTRING);
		supportedFunctions.add(SourceSystemFunctions.UCASE); //No Need of ALIAS as both ucase and upper work in HANA
		supportedFunctions.add(SourceSystemFunctions.RTRIM);
		
		///////////////////////////////////////////////////////////
		//NUMERIC FUNCTIONS////////////////////////////////////////
		///////////////////////////////////////////////////////////
		supportedFunctions.add(SourceSystemFunctions.ABS);
		supportedFunctions.add(SourceSystemFunctions.ACOS);
		supportedFunctions.add(SourceSystemFunctions.ASIN);
		supportedFunctions.add(SourceSystemFunctions.ATAN);
		supportedFunctions.add(SourceSystemFunctions.ATAN2);
		supportedFunctions.add(SourceSystemFunctions.CEILING);  ///ALIAS-ceil
		supportedFunctions.add(SourceSystemFunctions.COS);
		supportedFunctions.add(SourceSystemFunctions.COT);
		supportedFunctions.add(SourceSystemFunctions.EXP);
		supportedFunctions.add(SourceSystemFunctions.FLOOR);
		supportedFunctions.add(SourceSystemFunctions.LOG);
		supportedFunctions.add(SourceSystemFunctions.MOD);
		supportedFunctions.add(SourceSystemFunctions.POWER);
		supportedFunctions.add(SourceSystemFunctions.ROUND);
		supportedFunctions.add(SourceSystemFunctions.SIGN);	
		supportedFunctions.add(SourceSystemFunctions.SIN);
		supportedFunctions.add(SourceSystemFunctions.SQRT);
		supportedFunctions.add(SourceSystemFunctions.TAN);
		supportedFunctions.add(SourceSystemFunctions.RAND); 
		
		/////////////////////////////////////////////////////////////////////
		//BIT FUNCTIONS//////////////////////////////////////////////////////
		/////////////////////////////////////////////////////////////////////
		supportedFunctions.add(SourceSystemFunctions.BITAND);
		supportedFunctions.add(SourceSystemFunctions.BITOR);
		supportedFunctions.add(SourceSystemFunctions.BITNOT);
		supportedFunctions.add(SourceSystemFunctions.BITXOR);
		
		/////////////////////////////////////////////////////////////////////
		//DATE FUNCTIONS/////////////////////////////////////////////////////
		/////////////////////////////////////////////////////////////////////
		supportedFunctions.add(SourceSystemFunctions.CURDATE); 
		supportedFunctions.add(SourceSystemFunctions.CURTIME); 
		supportedFunctions.add(SourceSystemFunctions.DAYOFWEEK);
		supportedFunctions.add(SourceSystemFunctions.DAYOFMONTH); 
		supportedFunctions.add(SourceSystemFunctions.DAYOFYEAR);
		supportedFunctions.add(SourceSystemFunctions.DAYOFWEEK);
		supportedFunctions.add(SourceSystemFunctions.DAYNAME);
		supportedFunctions.add(SourceSystemFunctions.HOUR); 
		supportedFunctions.add(SourceSystemFunctions.MINUTE); 
		supportedFunctions.add(SourceSystemFunctions.MONTH);
		supportedFunctions.add(SourceSystemFunctions.MONTHNAME);
		supportedFunctions.add(SourceSystemFunctions.QUARTER);
		supportedFunctions.add(SourceSystemFunctions.SECOND);
		supportedFunctions.add(SourceSystemFunctions.WEEK);
		supportedFunctions.add(SourceSystemFunctions.YEAR);

        /////////////////////////////////////////////////////////////////////
		//SYSTEM FUNCTIONS///////////////////////////////////////////////////
        /////////////////////////////////////////////////////////////////////
		supportedFunctions.add(SourceSystemFunctions.IFNULL); 
		supportedFunctions.add(SourceSystemFunctions.NULLIF);
		
		/////////////////////////////////////////////////////////////////////
		//CONVERSION functions///////////////////////////////////////////////
		/////////////////////////////////////////////////////////////////////
		supportedFunctions.add(SourceSystemFunctions.CONVERT);
		
		/////////////////////////////////////////////////////////////////////
		//GEO Spatial functions//////////////////////////////////////////////
		/////////////////////////////////////////////////////////////////////
		supportedFunctions.add(SourceSystemFunctions.ST_SRID);
		supportedFunctions.add(SourceSystemFunctions.ST_ASBINARY);
		supportedFunctions.add(SourceSystemFunctions.ST_ASEWKT);
		supportedFunctions.add(SourceSystemFunctions.ST_ASTEXT);
		supportedFunctions.add(SourceSystemFunctions.ST_ASGEOJSON);
		supportedFunctions.add(SourceSystemFunctions.ST_CONTAINS);
		supportedFunctions.add(SourceSystemFunctions.ST_CROSSES);
		supportedFunctions.add(SourceSystemFunctions.ST_DISJOINT);
		supportedFunctions.add(SourceSystemFunctions.ST_DISTANCE);
		supportedFunctions.add(SourceSystemFunctions.ST_EQUALS);
		supportedFunctions.add(SourceSystemFunctions.ST_GEOMFROMTEXT);
		supportedFunctions.add(SourceSystemFunctions.ST_INTERSECTS);
		supportedFunctions.add(SourceSystemFunctions.ST_OVERLAPS);
		supportedFunctions.add(SourceSystemFunctions.ST_SRID);
		supportedFunctions.add(SourceSystemFunctions.ST_TOUCHES);
		
		
		return supportedFunctions;
	}

	public boolean supportsCompareCriteriaEquals() {
		return true;
	}

	public boolean supportsInCriteria() {
		return true;
	}

	@SuppressWarnings("unchecked")
	@Override
    public List<?> translateLimit(Limit limit, ExecutionContext context) {
    	if (limit.getRowOffset() > 0) {
    		return Arrays.asList("LIMIT ", limit.getRowLimit(), " OFFSET ", limit.getRowOffset()); //$NON-NLS-1$ //$NON-NLS-2$ 
    	}
        return null;
    }

	public void getMetadata(MetadataFactory metadataFactory,
			Connection connection) throws TranslatorException {
		super.getMetadata(metadataFactory, connection);
	}

	@Override
	public MetadataProcessor<Connection> getMetadataProcessor() {
		return new HanaMetadataProcessor();
	}

	@Override
	public boolean supportsOnlyLiteralComparison() {
		return true;
	}
	
	@Override
    public SQLConversionVisitor getSQLConversionVisitor() {
    	return new SQLConversionVisitor(this) {
    		
    		@Override
    		protected void translateSQLType(Class<?> type, Object obj,
    				StringBuilder valuesbuffer) {
    			if (type == TypeFacility.RUNTIME_TYPES.VARBINARY) {
    				valuesbuffer.append("to_binary("); //$NON-NLS-1$
    				super.translateSQLType(TypeFacility.RUNTIME_TYPES.STRING, obj, valuesbuffer);
    				valuesbuffer.append(")"); //$NON-NLS-1$
    			} else {
    				super.translateSQLType(type, obj, valuesbuffer);
    			}
    		}
    		
    	};
    }
	
	/**
     * Hana doesn't provide min/max(boolean)
     */
    @Override
    public List<?> translate(LanguageObject obj, ExecutionContext context) {
    	if (obj instanceof AggregateFunction) {
    		AggregateFunction agg = (AggregateFunction)obj;
    		if (agg.getParameters().size() == 1 
    				&& (agg.getName().equalsIgnoreCase(NonReserved.MIN) || agg.getName().equalsIgnoreCase(NonReserved.MAX)) 
    				&& TypeFacility.RUNTIME_TYPES.BOOLEAN.equals(agg.getParameters().get(0).getType())) {
        		return Arrays.asList("cast(", agg.getName(), "(to_tinyint(", agg.getParameters().get(0), ")) as boolean)"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
            }
    	}
    	return super.translate(obj, context);
    }
    
    @Override
    public String translateLiteralBoolean(Boolean booleanValue) {
    	if (booleanValue) {
    		return "true"; //$NON-NLS-1$
    	}
    	return "false"; //$NON-NLS-1$
    }
	
}
