/**
 * DataCleaner (community edition)
 * Copyright (C) 2014 Neopost - Customer Information Management
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * 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 Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.datacleaner.beans.transform;

import javax.inject.Named;

import org.datacleaner.api.Categorized;
import org.datacleaner.api.Configured;
import org.datacleaner.api.Description;
import org.datacleaner.api.InputColumn;
import org.datacleaner.api.InputRow;
import org.datacleaner.api.OutputColumns;
import org.datacleaner.api.Transformer;
import org.datacleaner.components.categories.TextCategory;

/**
 * Concatenates several values into one String value.
 *
 *
 */
@Named("Concatenator")
@Description("Concatenate several column values into one.")
@Categorized(TextCategory.class)
public class ConcatenatorTransformer implements Transformer {

    @Configured
    InputColumn<?>[] columns;

    @Configured(required = false)
    @Description("A string to separate the concatenated values")
    String separator;

    public ConcatenatorTransformer(final String separator, final InputColumn<?>[] columns) {
        this.separator = separator;
        this.columns = columns;
    }

    public ConcatenatorTransformer() {
    }

    @Override
    public OutputColumns getOutputColumns() {
        final StringBuilder sb = new StringBuilder("Concat of ");
        for (int i = 0; i < columns.length; i++) {
            if (i != 0) {
                sb.append(",");
            }
            sb.append(columns[i].getName());
            if (i == 4) {
                sb.append("...");
                // only include a preview of columns in the default name
                break;
            }
        }
        return new OutputColumns(String.class, sb.toString());
    }

    @Override
    public String[] transform(final InputRow inputRow) {
        final StringBuilder sb = new StringBuilder();
        boolean first = true;
        for (int i = 0; i < columns.length; i++) {
            final InputColumn<?> column = columns[i];
            final Object value = inputRow.getValue(column);
            if (value != null && !"".equals(value)) {
                if (!first && separator != null) {
                    sb.append(separator);
                }
                sb.append(value);
                first = false;
            }
        }
        return new String[] { sb.toString() };
    }

}