/**
 * 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 java.util.ArrayList;
import java.util.Date;
import java.util.List;

import javax.inject.Named;

import org.apache.metamodel.util.DateUtils;
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.DateAndTimeCategory;

@Named("Date difference / period length")
@Description("Calculates the length of a period made of two dates")
@Categorized(DateAndTimeCategory.class)
public class DateDiffTransformer implements Transformer {

    @Configured(order = 1)
    InputColumn<Date> fromColumn;

    @Configured(order = 2)
    InputColumn<Date> toColumn;

    @Configured(order = 3)
    boolean days = true;

    @Configured(order = 4)
    boolean hours = false;

    @Configured(order = 5)
    boolean minutes = false;

    @Configured(order = 6)
    boolean seconds = false;

    @Configured(order = 7)
    boolean milliseconds = false;

    @Override
    public OutputColumns getOutputColumns() {
        final List<String> columnNames = new ArrayList<>();
        final String from = fromColumn.getName();
        final String to = toColumn.getName();
        if (days) {
            columnNames.add("Days from " + from + " to " + to);
        }
        if (hours) {
            columnNames.add("Hours from " + from + " to " + to);
        }
        if (minutes) {
            columnNames.add("Minutes from " + from + " to " + to);
        }
        if (seconds) {
            columnNames.add("Seconds from " + from + " to " + to);
        }
        if (milliseconds || columnNames.isEmpty()) {
            columnNames.add("Milliseconds from " + from + " to " + to);
        }

        return new OutputColumns(Number.class, columnNames.toArray(new String[columnNames.size()]));
    }

    @Override
    public Number[] transform(final InputRow inputRow) {
        final Date from = inputRow.getValue(fromColumn);
        final Date to = inputRow.getValue(toColumn);
        return transform(from, to);
    }

    public Number[] transform(final Date from, final Date to) {
        final long fromTime = from == null ? 0 : from.getTime();
        final long toTime = to == null ? 0 : to.getTime();
        final long diff = toTime - fromTime;

        final List<Number> numbers = new ArrayList<>();
        if (days) {
            numbers.add(diff / DateUtils.MILLISECONDS_PER_DAY);
        }
        if (hours) {
            numbers.add(diff / DateUtils.MILLISECONDS_PER_HOUR);
        }
        if (minutes) {
            numbers.add(diff / DateUtils.MILLISECONDS_PER_MINUTE);
        }
        if (seconds) {
            numbers.add(diff / DateUtils.MILLISECONDS_PER_SECOND);
        }
        if (milliseconds || numbers.isEmpty()) {
            numbers.add(diff);
        }

        final Number[] result = new Number[numbers.size()];

        if (from == null || to == null) {
            // return an array with null's if either of the inputs are null
            return result;
        }
        return numbers.toArray(result);
    }

    public boolean isHours() {
        return hours;
    }

    public void setHours(final boolean hours) {
        this.hours = hours;
    }

    public void setDays(final boolean days) {
        this.days = days;
    }

    public void setMinutes(final boolean minutes) {
        this.minutes = minutes;
    }

    public void setSeconds(final boolean seconds) {
        this.seconds = seconds;
    }

    public void setMilliseconds(final boolean milliseconds) {
        this.milliseconds = milliseconds;
    }
}