/*
 * ECatalog is a database front-end, with two main features:
 * 1. Use of preferences
 *  A preference-based approach, where the user is allowed to define the importance of each criterion.
 *  Then the items are ranked accordingly to his criteria.
 * 2. Trade-off analysis
 *  A cooperative database approach, where the system "argues" with the user about his criteria.
 *  When there are no matching items, the system explains the minimal conflicting set and
 *  give some possible strong and weak relaxations about his criteria.
 * This package also containts the software and the set-up details used for our User Study,
 * comparing the use or not of the two previous features mentioned above.
 *
 * Copyright (C) 2006 David Portabella Clotet, Artificial Intelligence Laboratory, EPFL
 * 
 * This file is part of ecatalog-1.0.zip
 * 
 * ECatalog is free software and a free user study set-up;
 * 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 2 of the License, or
 * (at your option) any later version.
 * 
 * ECatalog 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 ECatalog; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * 
 * @version 1.0
 * @author David Portabella
 * To contact the author:
 * email: david@portabella.name and david.portabella@epfl.ch
 * 
 * More information about ECatalog:
 *  http://sourceforge.net/projects/ecatalog/
 *  http://icwww.epfl.ch/~portabel/ecatalogs/
 */

package ecatalog.db;

import ecatalog.ECatalog;

import dpc.utils.DebugUtil;
import dpc.utils.SqlUtil;
import dpc.utils.ArrayConverter;

import java.util.*;
import java.sql.*;
import ecatalog.jaxb.ecatalogConfig.AttributeType;

//import org.apache.bsf.BSFException;

public class NumberAttribute extends Attribute {
    /* The id of all the distinct possible values */
    private double[] valuesId;

    /* The index in the array valuesId and valuesString for a given value id */
    private HashMap<Double, Integer> valuesIndex;

    private double minValueId, maxValueId;
    
    public NumberAttribute(AttributeType config, Database db, int attributeIndex) {
	super(config, db, attributeIndex);
    }
    
    /* Computes valuesIndex, valuesId, nbrDistinctValues, minValueId, maxValueId and valuesString */
    public void init() throws SQLException, Exception {
	getValues();
	computeValuesString();
    }

    /* Computes valuesIndex, valuesId and nbrDistinctValues, minValueId, maxValueId */
    private void getValues() throws SQLException {
	Vector valuesIdVector = new Vector<Double>();
	valuesIndex = new HashMap<Double, Integer>();

	ResultSet rs = db.executeQuery("SELECT " + id + " FROM " + db.fromClause + " WHERE " + db.whereClause + " GROUP BY " + id + " ORDER BY " + id);
	int i = 0;
	while (rs.next()) {
	    String tmpString = rs.getString(1);
	    if (tmpString == null) {
		ECatalog.error(new Error("Null values not accepted now"));
		throw new Error(); //it is already done, but to avoid the java compiling error
	    }
	    
	    double tmp;
	    try { tmp = Double.parseDouble(tmpString); }
	    catch (NumberFormatException e) { 
		ECatalog.error(new Error("expected a double value")); 
		throw new Error(); //it is already done, but to avoid the java compiling error
	    }
	    valuesIdVector.add(tmp);
	    valuesIndex.put(tmp, i++);
	}
	rs.close();

	nbrDistinctValues = valuesIdVector.size();

	valuesId = ArrayConverter.toDoubles(valuesIdVector);

	minValueId = valuesId[0];
	maxValueId = valuesId[valuesId.length-1];
    }

    /* Computes valuesString */
    private void computeValuesString() throws Exception {
	valuesString = new String[nbrDistinctValues];
	String valueStringFunction = config.getValueStringFunction();
	if (valueStringFunction != null) {
	    //TODO minor: look at TextAttribute.java
	    for (int i = 0; i < valuesId.length; i++) {
		valuesString[i] = db.scriptEval("valueId = \"" + valuesId[i] + "\"; " + valueStringFunction).toString();
	    }
	} else {
	    for (int i = 0; i < valuesId.length; i++)
		valuesString[i] = String.valueOf(valuesId[i]);
	}
    }

    public double getMinValueId() { return minValueId; }
    public double getMaxValueId() { return maxValueId; }

    public int getValueIndex(double valueId) throws SQLException {
	return valuesIndex.get(valueId);
    }

    public int getValueIndex(ResultSet rs) throws SQLException {
	return getValueIndex(rs, dbColumnIndex);
    }

    public int getValueIndex(ResultSet rs, int dbColumnIndex) throws SQLException {
	return valuesIndex.get(rs.getDouble(dbColumnIndex));
    }

    public String getDbValueString(int valueIndex, boolean quoteIfNecessary) {
	return String.valueOf(valuesId[valueIndex]);
    }

    public double getValueId(int valueIndex) {
	return valuesId[valueIndex];
    }

    /* For a given valueIndex, it gets a string corresponding to the equal constraint on this value */
    public String getEqualConstraintString(int valueIndex) {
	EqualConstraint c = new EqualConstraint(this, db, new Weight(-1), null);
	c.setValueIndex(valueIndex);
	return c.getWithConstraintString();
    }
}