/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2014 by RapidMiner and the contributors
 *
 *  Complete list of developers available at our web site:
 *
 *       http://rapidminer.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.io;

import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.Date;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.Example;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.ParameterTypeDate;
import com.rapidminer.tools.io.Encoding;

/**
 * Writes values of all examples into an ARFF file which can be used
 * by the machine learning library Weka. The ARFF format is described in the
 * {@link ArffExampleSource} operator which is able to read ARFF files to
 * make them usable with RapidMiner.
 * 
 * @rapidminer.index arff
 * @author Ingo Mierswa
 */
public class ArffExampleSetWriter extends AbstractStreamWriter {

	/** The parameter name for "File to save the example set to." */
	public static final String PARAMETER_EXAMPLE_SET_FILE = "example_set_file";

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

	@Override
	void writeStream(ExampleSet exampleSet, OutputStream outputStream) throws OperatorException {
		PrintWriter out = null;
		try {
			out = new PrintWriter(new OutputStreamWriter(outputStream, Encoding.getEncoding(this)));
			writeArff(exampleSet, out);
			out.flush();
		} finally {
			if (out != null) {
				out.close();
			}
		}
	}

	/*
	    @Override
	    public ExampleSet write(ExampleSet exampleSet) throws OperatorException {
	        try {
	            File arffFile = getParameterAsFile(PARAMETER_EXAMPLE_SET_FILE, true);
	            PrintWriter out = new PrintWriter(new OutputStreamWriter(new FileOutputStream(arffFile), Encoding.getEncoding(this)));
	            writeArff(exampleSet, out);
	            out.flush();
	            out.close();
	        } catch (IOException e) {
	            throw new UserError(this, e, 303, new Object[] { getParameterAsString(PARAMETER_EXAMPLE_SET_FILE), e.getMessage() });
	        }
	        return exampleSet;
	    }*/

	public static void writeArff(ExampleSet exampleSet, PrintWriter out, String linefeed) {
		if (linefeed == null) {
			linefeed = System.getProperty("line.separator");
		}

		// relation
		out.print("@RELATION RapidMinerData" + linefeed);
		out.print(linefeed);

		// attribute meta data
		Iterator<Attribute> a = exampleSet.getAttributes().allAttributes();
		while (a.hasNext()) {
			printAttributeData(a.next(), out);
		}

		// data
		out.print(linefeed);
		out.print("@DATA" + linefeed);

		for (Example example : exampleSet) {
			boolean first = true;
			a = exampleSet.getAttributes().allAttributes();
			while (a.hasNext()) {
				Attribute current = a.next();
				if (!first)
					out.print(",");

				if (current.isNominal()) {
					double value = example.getValue(current);
					if (Double.isNaN(value))
						out.print("?");
					else
						out.print("'" + example.getValueAsString(current) + "'");
				} else if (current.isDateTime()) {
					Date dateValue = example.getDateValue(current);
					out.print("\"" + ParameterTypeDate.DATE_FORMAT.format(dateValue)+ "\"");
				} else {
					out.print(example.getValueAsString(current));
				}
				first = false;
			}
			out.print(linefeed);
		}
	}

	public static void writeArff(ExampleSet exampleSet, PrintWriter out) {
		writeArff(exampleSet, out, null);
	}

	private static void printAttributeData(Attribute attribute, PrintWriter out) {
		out.print("@ATTRIBUTE '" + attribute.getName() + "' ");
		if (attribute.isNominal()) {
			StringBuffer nominalValues = new StringBuffer("{");
			boolean first = true;
			for (String s : attribute.getMapping().getValues()) {
				if (!first)
					nominalValues.append(",");
				nominalValues.append("'" + s + "'");
				first = false;
			}
			nominalValues.append("}");
			out.print(nominalValues.toString());
		} else if (attribute.isDateTime())
			out.print("DATE \"" + ParameterTypeDate.DATE_FORMAT.toPattern() + "\"");
		else {
			out.print("real");
		}
		out.println();
	}

	@Override
	protected boolean supportsEncoding() {
		return true;
	}

	@Override
	public List<ParameterType> getParameterTypes() {
		List<ParameterType> types = new LinkedList<ParameterType>();
		types.add(makeFileParameterType());
		//types.add(new ParameterTypeFile(PARAMETER_EXAMPLE_SET_FILE, "File to save the example set to.", "arff", false));
		types.addAll(super.getParameterTypes());
		return types;
	}

	@Override
	String[] getFileExtensions() {
		return new String[] { "arff" };
	}

	@Override
	String getFileParameterName() {
		return PARAMETER_EXAMPLE_SET_FILE;
	}

}