/*
 *  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.io;

import java.io.File;
import java.util.LinkedList;
import java.util.List;

import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.UserError;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.ParameterTypeCategory;
import com.rapidminer.parameter.UndefinedParameterError;

/** Provides functionality to determine whether files should be overwritten or appended to.
 * 
 * @author Simon Fischer
 *
 */
public abstract class AppendingExampleSetWriter extends AbstractExampleSetWriter {

	/** The parameter name for "Indicates if an existing table should be overwritten." */
	public static final String PARAMETER_OVERWRITE_MODE = "overwrite_mode";


	public static final String[] OVERWRITE_MODES = new String[] {
		"none",
		"overwrite first, append then",
		"overwrite",
		"append"
	};

	public static final int OVERWRITE_MODE_NONE            = 0;
	public static final int OVERWRITE_MODE_OVERWRITE_FIRST = 1;
	public static final int OVERWRITE_MODE_OVERWRITE       = 2;
	public static final int OVERWRITE_MODE_APPEND          = 3;

	public AppendingExampleSetWriter(OperatorDescription description) {
		super(description);
	}
	
	protected boolean shouldAppend(File dataFile) throws UndefinedParameterError, UserError {
		int overwriteMode = getParameterAsInt(PARAMETER_OVERWRITE_MODE);
		boolean append = false;
		switch (overwriteMode) {
		case OVERWRITE_MODE_NONE:
			if (dataFile.exists()) {
				throw new UserError(this, 100);
			}
			append = false;
			break;
		case OVERWRITE_MODE_OVERWRITE:
			if (dataFile.exists()) {
				getLogger().info("File " + dataFile + " already exists. Overwriting...");
			}
			append = false;
			break;
		case OVERWRITE_MODE_APPEND:
			if (dataFile.exists()) {
				getLogger().info("File " + dataFile + " already exists. Appending...");
			}
			append = true;
			break;
		case OVERWRITE_MODE_OVERWRITE_FIRST:
		default:
			if (getApplyCount() <= 1) { // first time
				if (dataFile.exists()) {
					getLogger().info("File " + dataFile + " already exists. Overwriting this time...");
				}	
				append = false;
			} else {
				if (dataFile.exists()) {
					getLogger().info("File " + dataFile + " already exists. Appending...");
				}
				append = true;
			}
			break;
		}
		return append;
	}

	@Override
	public List<ParameterType> getParameterTypes() {
		List<ParameterType> types = new LinkedList<ParameterType>();		
		types.add(new ParameterTypeCategory(PARAMETER_OVERWRITE_MODE, "Indicates if an existing table should be overwritten or if data should be appended.", OVERWRITE_MODES, OVERWRITE_MODE_OVERWRITE_FIRST));
		types.addAll(super.getParameterTypes());
		return types;
	}

}