/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.oozie.example;

import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Properties;
import java.util.TimeZone;

public class DateList {
    private static final TimeZone UTC = getTimeZone("UTC");
    private static String DATE_LIST_SEPARATOR = ",";

    public static void main(String[] args) throws Exception {
        if (args.length < 5) {
            System.out
                    .println("Usage: java DateList <start_time>  <end_time> <frequency> <timeunit> <timezone>");
            System.out
                    .println("Example: java DateList 2009-02-01T01:00Z 2009-02-01T02:00Z 15 MINUTES UTC");
            System.exit(1);
        }
        Date startTime = parseDateUTC(args[0]);
        Date endTime = parseDateUTC(args[1]);
        Repeatable rep = new Repeatable();
        rep.setBaseline(startTime);
        rep.setFrequency(Integer.parseInt(args[2]));
        rep.setTimeUnit(TimeUnit.valueOf(args[3]));
        rep.setTimeZone(getTimeZone(args[4]));
        int occurrence = 0;
        Date date = rep.getOccurrenceTime(startTime, occurrence++, null);
        StringBuilder dateList = new StringBuilder();
        while (date != null && date.before(endTime)) {
            date = rep.getOccurrenceTime(startTime, occurrence++, null);
            if (occurrence > 1) {
                dateList.append(DATE_LIST_SEPARATOR);
            }
            dateList.append(formatDateUTC(date));
        }

        System.out.println("datelist :" + dateList+ ":");
        //Passing the variable to WF that could be referred by subsequent actions
        File file = new File(System.getProperty("oozie.action.output.properties"));
        Properties props = new Properties();
        props.setProperty("datelist", dateList.toString());
        try (OutputStream os = new FileOutputStream(file)) {
            props.store(os, "");
        }
    }
    //Utility methods
    private static DateFormat getISO8601DateFormat() {
        DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm'Z'");
        dateFormat.setTimeZone(UTC);
        return dateFormat;
    }

    private static TimeZone getTimeZone(String tzId) {
        TimeZone tz = TimeZone.getTimeZone(tzId);
        if (!tz.getID().equals(tzId)) {
            throw new IllegalArgumentException("Invalid TimeZone: " + tzId);
        }
        return tz;
    }

    private static Date parseDateUTC(String s) throws Exception {
        return getISO8601DateFormat().parse(s);
    }

    private static String formatDateUTC(Date d) throws Exception {
        return (d != null) ? getISO8601DateFormat().format(d) : "NULL";
    }
}
