// 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 com.cloud.bridge.util;

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

public class DateHelper {
    public static final TimeZone GMT_TIMEZONE = TimeZone.getTimeZone("GMT");
    public static final String YYYYMMDD_FORMAT = "yyyyMMddHHmmss";

    public static Date currentGMTTime() {
        return new Date();
    }

    public static SimpleDateFormat getGMTDateFormat(String format) {
        SimpleDateFormat df = new SimpleDateFormat(format);
        df.setTimeZone(TimeZone.getTimeZone("GMT"));
        return df;
    }

    public static Date parseDateString(TimeZone tz, String dateString) {
        return parseDateString(tz, dateString, "yyyy-MM-dd HH:mm:ss");
    }

    public static Date parseISO8601DateString(String dateString) throws ParseException {
        // -> SimpleDateFormat uses GMT[-+]hh:mm for the TZ so first we need to
        //    convert the string with this value
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssz");

        //this is zero time so we need to add that TZ indicator for
        if (dateString.endsWith("Z")) {
            dateString = dateString.substring(0, dateString.length() - 1) + "GMT-00:00";
        } else {    // -> -0700 is valid but we need to change it to -07:00 for SimpleDateFormat
            dateString = dateString.replaceFirst("-(\\d\\d)(\\d\\d)", "-$1:$2");

            int inset = 6;
            String s0 = dateString.substring(0, dateString.length() - inset);
            String s1 = dateString.substring(dateString.length() - inset, dateString.length());
            dateString = s0 + "GMT" + s1;
        }

        //System.out.println( "parseDate: [" + dateString + "]" );
        return df.parse(dateString);
    }

    public static Date parseDateString(TimeZone tz, String dateString, String formatString) {
        DateFormat df = new SimpleDateFormat(formatString);
        df.setTimeZone(tz);

        try {
            return df.parse(dateString);
        } catch (ParseException e) {
            throw new IllegalArgumentException(e);
        }
    }

    public static String getDateDisplayString(TimeZone tz, Date time) {
        return getDateDisplayString(tz, time, "yyyy-MM-dd HH:mm:ss");
    }

    public static String getDateDisplayString(TimeZone tz, Date time, String formatString) {
        DateFormat df = new SimpleDateFormat(formatString);
        df.setTimeZone(tz);

        return df.format(time);
    }

    public static Calendar toCalendar(Date dt) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(dt);
        return calendar;
    }
}