/*
 *  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.text.NumberFormat;
import java.text.ParseException;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;

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.UserError;
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.GuessValueTypes;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.UndefinedParameterError;
import com.rapidminer.tools.Ontology;
import com.rapidminer.tools.OperatorResourceConsumptionHandler;
import com.rapidminer.tools.StrictDecimalFormat;
import com.rapidminer.tools.math.container.Range;


/**
 * <p>This operator transforms nominal attributes into numerical ones. In contrast to
 * the NominalToNumeric operator, this operator directly parses numbers from
 * the wrongly as nominal values encoded values. Please note that this operator
 * will first check the stored nominal mappings for all attributes. If (old) mappings
 * are still stored which actually are nominal (without the corresponding data being part of 
 * the example set), the attribute will not be converted. Please use the operator
 * {@link GuessValueTypes} in these cases.</p>
 * 
 * @author Regina Fritsch, Ingo Mierswa
 */
public class NominalNumbers2Numerical extends AbstractFilteredDataProcessing {

	/** The parameter name for "Character that is used as decimal point." */
	public static final String PARAMETER_DECIMAL_POINT_CHARACTER = "decimal_point_character";

	/** Used for separation of digits (1,000,000.0 or 1.000.000,0) . */
	public static final String PARAMETER_GROUP_SEPARATOR = "group_separator";

	public NominalNumbers2Numerical(OperatorDescription description) {
		super(description);
	}

	@Override
	public ExampleSetMetaData applyOnFilteredMetaData(ExampleSetMetaData emd) throws UndefinedParameterError {
		NumberFormat format = makeFormat();
		
		Iterator<AttributeMetaData> iterator = emd.getAllAttributes().iterator();
		List<AttributeMetaData> affectedList = new LinkedList<AttributeMetaData>();
		while (iterator.hasNext()) {
			AttributeMetaData amd = iterator.next();
			if (amd.isNominal()) {
				Set<String> values = amd.getValueSet();
				// check if values are transformed
				boolean isTransformed = true;
				double min = Double.POSITIVE_INFINITY;
				double max = Double.NEGATIVE_INFINITY;

				try {
					for (String value : values) {
						double numValue = format.parse(value).doubleValue();
						min = Math.min(min, numValue);
						max = Math.max(max, numValue);
					}
				} catch (ParseException e) { 
					isTransformed = false;
				}

				if (isTransformed) {
					// removing and inserting in order to reflect correct order
					iterator.remove(); 
					affectedList.add(amd);

					// transform attribute
					amd.setType(Ontology.NUMERICAL);
					if (min == Double.POSITIVE_INFINITY) {
						min = Double.NEGATIVE_INFINITY;
					}
					if (max == Double.NEGATIVE_INFINITY) {
						max = Double.POSITIVE_INFINITY;
					}
					amd.setValueRange(new Range(min, max), SetRelation.EQUAL);
				}
			}
		}
		emd.addAllAttributes(affectedList);
		return emd;
	}
	
	@Override
	public ExampleSet applyOnFiltered(ExampleSet exampleSet) throws OperatorException {
		NumberFormat format = makeFormat();
		
		List<Attribute> newAttributes = new LinkedList<Attribute>();
		// using iterator for avoiding "concurrent modification"
		Iterator<Attribute> a = exampleSet.getAttributes().iterator();
		while (a.hasNext()) {
			Attribute attribute = a.next();
			if (attribute.isNominal()) {
				boolean isNumericalNominal = true;
				try {
					for(String value : attribute.getMapping().getValues()) {
						format.parse(value);
					}
				} catch (Exception e){
					isNumericalNominal = false;
				}

				if (isNumericalNominal) {
					// new attribute
					Attribute newAttribute = AttributeFactory.createAttribute(Ontology.NUMERICAL);
					exampleSet.getExampleTable().addAttribute(newAttribute);
					newAttributes.add(newAttribute);

					// copy data
					for (Example e : exampleSet) {
						double oldValue = e.getValue(attribute);
						if (!Double.isNaN(oldValue)) {
							String value = e.getValueAsString(attribute);
							try {
								e.setValue(newAttribute, format.parse(value).doubleValue());
							} catch (ParseException ex) {
								throw new UserError(this, ex, 946, value);
							}
						} else {
							e.setValue(newAttribute, Double.NaN);
						}
					}

					// delete attribute and rename the new attribute
					a.remove();
					newAttribute.setName(attribute.getName());
				}
			}
		}

		for (Attribute attribute : newAttributes) {
			exampleSet.getAttributes().addRegular(attribute);
		}

		return exampleSet;
	}

	private NumberFormat makeFormat() throws UndefinedParameterError {
		StrictDecimalFormat format = StrictDecimalFormat.getInstance(this);
		return format;
	}



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

	@Override
	public List<ParameterType> getParameterTypes() {
		List<ParameterType> types = super.getParameterTypes();
		types.addAll(StrictDecimalFormat.getParameterTypes(this));
		// TODO: Replace old parameters by new ones
//		types.add(new ParameterTypeChar(PARAMETER_DECIMAL_POINT_CHARACTER, "Character that is used as decimal point.", '.', false));
//		types.add(new ParameterTypeChar(PARAMETER_GROUP_SEPARATOR, "Character that is used to separate groups (e.g. in 1.000.000 or 1,000,000).", false));
		return types;
	}
	
	@Override
	public boolean writesIntoExistingData() {
		return false;
	}
	
	@Override
	public ResourceConsumptionEstimator getResourceConsumptionEstimator() {
		return OperatorResourceConsumptionHandler.getResourceConsumptionEstimator(getInputPort(), NominalNumbers2Numerical.class, null);
	}

}