/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2011 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.operator.preprocessing.filter;

import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map.Entry;
import java.util.Set;
import java.util.TreeSet;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.Example;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.table.AttributeFactory;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.annotation.ResourceConsumptionEstimator;
import com.rapidminer.operator.ports.metadata.AttributeMetaData;
import com.rapidminer.operator.ports.metadata.ExampleSetMetaData;
import com.rapidminer.operator.ports.metadata.SetRelation;
import com.rapidminer.operator.preprocessing.AbstractValueProcessing;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.ParameterTypeRegexp;
import com.rapidminer.parameter.ParameterTypeString;
import com.rapidminer.parameter.UndefinedParameterError;
import com.rapidminer.tools.Ontology;
import com.rapidminer.tools.OperatorResourceConsumptionHandler;


/**
 * <p>This operator creates new attributes from nominal attributes where
 * the new attributes contain the original values which replaced substrings.
 * The replace_what parameter can be defined as a regular expression (please
 * refer to the annex of the RapidMiner tutorial for a description). The
 * replace_by parameter can be defined as an arbitrary string. Empty strings
 * are also allowed. Capturing groups of the defined regular expression can
 * be accessed with $1, $2, $3...</p>
 *  
 * @author Ingo Mierswa, Helge Homburg, Tobias Malbrecht
 */
public class AttributeValueReplace extends AbstractValueProcessing {

	public static final String PARAMETER_REPLACE_WHAT = "replace_what";

	public static final String PARAMETER_REPLACE_BY = "replace_by";


	public AttributeValueReplace(OperatorDescription description) {
		super(description);
	}

	@Override
	public ExampleSetMetaData applyOnFilteredMetaData(ExampleSetMetaData emd) throws UndefinedParameterError {
		String  replaceWhat = getParameterAsString(PARAMETER_REPLACE_WHAT);
		Pattern whatPattern = Pattern.compile(replaceWhat);
		String  replaceBy   = "";
		if (isParameterSet(PARAMETER_REPLACE_BY)) {
			replaceBy = getParameterAsString(PARAMETER_REPLACE_BY);
		}

		for (AttributeMetaData amd : emd.getAllAttributes()) {
			Set<String> valueSet = new TreeSet<String>();
			for (String value : amd.getValueSet()) {
				Matcher whatMatcher = whatPattern.matcher(value);
				String replacedValue = whatMatcher.replaceAll(replaceBy);
				if (replacedValue.length() > 0) {
					valueSet.add(replacedValue);
				}
			}
			amd.setValueSet(valueSet, SetRelation.SUBSET);
		}

		return emd;
	}


	@Override
	public ExampleSet applyOnFiltered(ExampleSet exampleSet) throws OperatorException {
		String  replaceWhat = getParameterAsString(PARAMETER_REPLACE_WHAT);
		Pattern whatPattern = Pattern.compile(replaceWhat);
		String  replaceBy   = "";
		if (isParameterSet(PARAMETER_REPLACE_BY)) {
			replaceBy = getParameterAsString(PARAMETER_REPLACE_BY);
		}

		LinkedHashMap<Attribute, Attribute> attributeMap = new LinkedHashMap<Attribute, Attribute>();
		for (Attribute oldAttribute : exampleSet.getAttributes()) {
			Attribute newAttribute = AttributeFactory.createAttribute(oldAttribute.getValueType());
			attributeMap.put(oldAttribute, newAttribute);
			for (String value : oldAttribute.getMapping().getValues()) {
				Matcher whatMatcher = whatPattern.matcher(value);
				String replacedValue = whatMatcher.replaceAll(replaceBy);
				if (replacedValue.length() > 0) {
					newAttribute.getMapping().mapString(replacedValue);
				}
			}
		}		

		for (Entry<Attribute, Attribute> entry : attributeMap.entrySet()) {
			Attribute oldAttribute = entry.getKey();
			Attribute newAttribute = entry.getValue();
			exampleSet.getExampleTable().addAttribute(newAttribute);
			exampleSet.getAttributes().addRegular(newAttribute);
			for (Example example : exampleSet) {
				double value = example.getValue(oldAttribute);
				if (Double.isNaN(value)) {
					example.setValue(newAttribute, Double.NaN);
				} else {
					String stringValue = oldAttribute.getMapping().mapIndex((int) value);				
					Matcher whatMatcher = whatPattern.matcher(stringValue);
					String newValue = whatMatcher.replaceAll(replaceBy);
					if (newValue.length() == 0) {
						example.setValue(newAttribute, Double.NaN);
					} else {
						example.setValue(newAttribute, newAttribute.getMapping().mapString(newValue));
					}
				}
			}
			exampleSet.getAttributes().remove(oldAttribute);
			newAttribute.setName(oldAttribute.getName());
			newAttribute.setConstruction("replace(" + oldAttribute.getName()+ "," + replaceWhat + "," + replaceBy + ")");
		}
		return exampleSet;
	}

	@Override
	protected int[] getFilterValueTypes() {
		return new int[] { Ontology.NOMINAL };
	}

	@Override
	public List<ParameterType> getParameterTypes() {
		List<ParameterType> types = super.getParameterTypes();
		types.add(new ParameterTypeRegexp(PARAMETER_REPLACE_WHAT, "A regular expression specifying what should be replaced.", false, false));
		types.add(new ParameterTypeString(PARAMETER_REPLACE_BY, "The replacement for the region matched by the regular expression. Possibly including capturing groups.", true, false));
		return types;
	}
	
	@Override
	public boolean writesIntoExistingData() {
		return false;
	}
	
	@Override
	public ResourceConsumptionEstimator getResourceConsumptionEstimator() {
		return OperatorResourceConsumptionHandler.getResourceConsumptionEstimator(getInputPort(), AttributeValueReplace.class, null);
	}
}