/*
 *  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.tools.io;

import java.nio.charset.Charset;
import java.nio.charset.IllegalCharsetNameException;
import java.nio.charset.UnsupportedCharsetException;
import java.util.LinkedList;
import java.util.List;

import com.rapidminer.RapidMiner;
import com.rapidminer.operator.Operator;
import com.rapidminer.operator.UserError;
import com.rapidminer.parameter.ParameterHandler;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.ParameterTypeStringCategory;
import com.rapidminer.parameter.UndefinedParameterError;
import com.rapidminer.tools.ParameterService;

/** Collection of static helper methods to add and evaluate parameters to specify an encoding.
 * 
 * @author Sebastian Land
 *
 */
public class Encoding {

    public static final String PARAMETER_ENCODING = "encoding";

    public static final String[] CHARSETS;
    static {
        CHARSETS = new String[Charset.availableCharsets().size()+1];
        CHARSETS[0] = RapidMiner.SYSTEM_ENCODING_NAME;
        int i = 0;
        for (String charSet : Charset.availableCharsets().keySet()) {
            CHARSETS[i+1] = charSet;
            i++;
        }
    }

    public static Charset getEncoding(Operator handler) throws UndefinedParameterError, UserError {
        String selectedCharsetName = handler.getParameterAsString(PARAMETER_ENCODING);
        if (RapidMiner.SYSTEM_ENCODING_NAME.equals(selectedCharsetName)) {
            return Charset.defaultCharset();
        }
        try {
            return Charset.forName(selectedCharsetName);
        } catch (IllegalCharsetNameException e) {
            throw new UserError(handler, 207, selectedCharsetName, PARAMETER_ENCODING, "No legal charset name.");
        } catch (UnsupportedCharsetException e) {
            throw new UserError(handler, 207, selectedCharsetName, PARAMETER_ENCODING, "Charset not supported on this Java VM.");
        } catch (IllegalArgumentException e) {
            throw new UserError(handler, 207, selectedCharsetName, PARAMETER_ENCODING, "Select different charset.");
        }
    }

    public static Charset getEncoding(String charsetName) {
        if (RapidMiner.SYSTEM_ENCODING_NAME.equals(charsetName)) {
            return Charset.defaultCharset();
        }
        return Charset.forName(charsetName);
    }


    public static List<ParameterType> getParameterTypes(ParameterHandler handler) {
        List<ParameterType> types = new LinkedList<ParameterType>();

        String encoding = RapidMiner.SYSTEM_ENCODING_NAME;
        String encodingProperty = ParameterService.getParameterValue(RapidMiner.PROPERTY_RAPIDMINER_GENERAL_DEFAULT_ENCODING);
        if (encodingProperty != null)
            encoding = encodingProperty;
        types.add(new ParameterTypeStringCategory(PARAMETER_ENCODING, "The encoding used for reading or writing files.", CHARSETS, encoding, false));

        return types;
    }
}