/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2008 by Rapid-I and the contributors
 *
 *  Complete list of developers available at our web site:
 *
 *       http://rapid-i.com
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see http://www.gnu.org/licenses/.
 */
package com.rapidminer.example.set;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.AttributeRole;
import com.rapidminer.example.AttributeTransformation;
import com.rapidminer.example.Attributes;
import com.rapidminer.example.Example;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.Statistics;
import com.rapidminer.example.table.ExampleTable;

/**
 * An implementation of ExampleSet that allows the replacement of missing values
 * on the fly. Missing values will be replaced by the average of all other values
 * or by the mean.
 * 
 * @author Ingo Mierswa
 * @version $Id: ReplaceMissingExampleSet.java,v 1.8 2008/05/09 19:22:49 ingomierswa Exp $
 */
public class ReplaceMissingExampleSet extends AbstractExampleSet {

	private static final long serialVersionUID = -5662936146589379273L;

	/** Currently used attribute weights. Used also for example creation. */
	private Map<String, Double> replacementMap;
	
	/** The parent example set. */
	private ExampleSet parent;
    
	public ReplaceMissingExampleSet(ExampleSet exampleSet) {
		this(exampleSet, null);
	}

	public ReplaceMissingExampleSet(ExampleSet exampleSet, Map<String, Double> replacementMap) {
		this.parent = (ExampleSet)exampleSet.clone();
		if (replacementMap == null) {
			this.replacementMap = new HashMap<String, Double>();
			for (Attribute attribute : parent.getAttributes())
				addReplacement(attribute);
		} else {
			this.replacementMap = replacementMap;
		}
		
        Iterator<AttributeRole> a = this.parent.getAttributes().allAttributeRoles();
        while (a.hasNext()) {
            AttributeRole role = a.next();
            Attribute currentAttribute = role.getAttribute();
            currentAttribute.addTransformation(new AttributeTransformationReplaceMissing(this.replacementMap));
        }
	}

	/** Clone constructor. */
	public ReplaceMissingExampleSet(ReplaceMissingExampleSet exampleSet) {
    	this.parent = (ExampleSet)exampleSet.parent.clone();
		this.replacementMap = new HashMap<String, Double>();
		for (String name : exampleSet.replacementMap.keySet()) {
			this.replacementMap.put(name, Double.valueOf(exampleSet.replacementMap.get(name).doubleValue()));
		}
		
        Iterator<AttributeRole> a = this.parent.getAttributes().allAttributeRoles();
        while (a.hasNext()) {
            AttributeRole role = a.next();
            Attribute currentAttribute = role.getAttribute();
			AttributeTransformation transformation = currentAttribute.getLastTransformation();
			if (transformation != null)
				if (transformation instanceof AttributeTransformationReplaceMissing)
					((AttributeTransformationReplaceMissing)transformation).setReplacementMap(this.replacementMap);
		}
	}

	public Map<String, Double> getReplacementMap() {
		return this.replacementMap;
	}
	
	public void addReplacement(Attribute attribute) {
		recalculateAttributeStatistics(attribute);
		if (attribute.isNominal())
			this.replacementMap.put(attribute.getName(), getStatistics(attribute, Statistics.MODE));
		else
			this.replacementMap.put(attribute.getName(), getStatistics(attribute, Statistics.AVERAGE));
	}
	
	public Attributes getAttributes() {
		return this.parent.getAttributes();
	}

	public boolean equals(Object o) {
		if (!super.equals(o))
			return false;
		if (!(o instanceof ReplaceMissingExampleSet))
			return false;
		boolean result = super.equals(o);
		if (result) {
			Map<String,Double> otherMap = ((ReplaceMissingExampleSet)o).replacementMap;
			if (this.replacementMap.size() != otherMap.size())
				return false;
			for (String name : this.replacementMap.keySet()) {
				if (!this.replacementMap.get(name).equals(otherMap.get(name)))
					return false;
			}
		}
		return true;
	}

	public int hashCode() {
		return super.hashCode() ^ replacementMap.hashCode();
	}

    /**
     * Creates a new example set reader.
     */
    public Iterator<Example> iterator() {
        return new AttributesExampleReader(parent.iterator(), this);
    }

    public Example getExample(int index) {
    	return this.parent.getExample(index);
    }
    
	public ExampleTable getExampleTable() {
		return parent.getExampleTable();
	}

	public int size() {
		return parent.size();
	}
}