/*
 *  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;

import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.AttributeRole;
import com.rapidminer.example.Attributes;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.example.set.ModelViewExampleSet;
import com.rapidminer.example.set.NonSpecialAttributesExampleSet;
import com.rapidminer.example.set.RemappedExampleSet;
import com.rapidminer.operator.AbstractModel;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.ViewModel;
import com.rapidminer.tools.Tools;
import com.rapidminer.tools.container.Pair;

/**
 * Returns a more appropriate result icon. This model allows preprocessing
 * Operators to be applied through a view without changing the underlying data.
 * Since Apply Model does not know the models, because they are wrapped within a
 * container model, it is necessary to ask for the parameter PARAMETER_CREATE_VIEW.
 * This must be set by Apply Model, and should be the default behavior.
 * 
 * @author Ingo Mierswa, Sebastian Land
 */
public abstract class PreprocessingModel extends AbstractModel implements ViewModel {
    private static final long serialVersionUID = -2603663450216521777L;

    private HashMap<String, Object> parameterMap = new HashMap<String, Object>();

    protected PreprocessingModel(ExampleSet exampleSet) {
        super(exampleSet);
    }

    /**
     * Applies the model by changing the underlying data
     */
    public abstract ExampleSet applyOnData(ExampleSet exampleSet) throws OperatorException;

    @Override
    public ExampleSet apply(ExampleSet exampleSet) throws OperatorException {
        // adapting example set to contain only attributes, which were present during learning time and
        // remove roles if necessary
        ExampleSet nonSpecialRemapped = new RemappedExampleSet( (isSupportingAttributeRoles()) ? exampleSet: new NonSpecialAttributesExampleSet(exampleSet), getTrainingHeader(), false);
        LinkedList<AttributeRole> unusedList = new LinkedList<AttributeRole>();
        Iterator<AttributeRole> iterator = exampleSet.getAttributes().allAttributeRoles();
        while (iterator.hasNext()) {
            AttributeRole role = iterator.next();
            if (nonSpecialRemapped.getAttributes().get(role.getAttribute().getName()) == null) {
                unusedList.add(role);
            }
        }


        // applying by creating view or changing data
        boolean createView = false;
        if (parameterMap.containsKey(PreprocessingOperator.PARAMETER_CREATE_VIEW)) {
            Boolean booleanObject = ((Boolean)parameterMap.get(PreprocessingOperator.PARAMETER_CREATE_VIEW));
            createView = false;
            if (booleanObject != null)
                createView = booleanObject.booleanValue();
        }

        ExampleSet result;
        if (createView) {
            // creating only view
            result = new ModelViewExampleSet(nonSpecialRemapped, this);
        } else {
            result = applyOnData(nonSpecialRemapped);
        }

        // restoring roles if possible
        Iterator<Attribute> attributeIterator = result.getAttributes().allAttributes();
        List<Pair<Attribute, String>> roleList = new LinkedList<Pair<Attribute, String>>();
        Attributes inputAttributes = exampleSet.getAttributes();
        while (attributeIterator.hasNext()) {
            Attribute resultAttribute = attributeIterator.next();
            AttributeRole role = inputAttributes.getRole(resultAttribute.getName());
            if (role != null && role.isSpecial())
                roleList.add(new Pair<Attribute, String>(resultAttribute, role.getSpecialName()));  // since underlying connection is changed
        }
        for (Pair<Attribute, String> rolePair: roleList)
            result.getAttributes().setSpecialAttribute(rolePair.getFirst(), rolePair.getSecond());

        // adding unused
        Attributes resultAttributes = result.getAttributes();
        for(AttributeRole role: unusedList) {
            resultAttributes.add(role);
        }
        return result;
    }

    @Override
    public String toResultString() {
        StringBuilder builder = new StringBuilder();
        Attributes trainAttributes = getTrainingHeader().getAttributes();
        builder.append(getName()+ Tools.getLineSeparators(2));
        builder.append("Model covering " + trainAttributes.size() + " attributes:" + Tools.getLineSeparator());
        for (Attribute attribute: trainAttributes) {
            builder.append(" - " + attribute.getName() + Tools.getLineSeparator());
        }
        return builder.toString();
    }

    @Override
    public void setParameter(String key, Object value) {
        parameterMap.put(key, value);
    }

    /**
     * Subclasses which need to have the attribute roles must return true. Otherwise
     * all selected attributes are converted into regular and afterwards given their old
     * roles.
     */
    public boolean isSupportingAttributeRoles() {
        return false;
    }
}