/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed 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.android.bluetooth.pbapclient.utils;

import java.util.Calendar;
import java.util.Date;
import java.util.Locale;
import java.util.TimeZone;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public final class ObexTime {

    private Date mDate;

    public ObexTime(String time) {
        /*
         * match OBEX time string: YYYYMMDDTHHMMSS with optional UTF offset
         * +/-hhmm
         */
        Pattern p = Pattern
                .compile("(\\d{4})(\\d{2})(\\d{2})T(\\d{2})(\\d{2})(\\d{2})(([+-])(\\d{2})(\\d{2}))?");
        Matcher m = p.matcher(time);

        if (m.matches()) {

            /*
             * matched groups are numberes as follows: YYYY MM DD T HH MM SS +
             * hh mm ^^^^ ^^ ^^ ^^ ^^ ^^ ^ ^^ ^^ 1 2 3 4 5 6 8 9 10 all groups
             * are guaranteed to be numeric so conversion will always succeed
             * (except group 8 which is either + or -)
             */

            Calendar cal = Calendar.getInstance();
            cal.set(Integer.parseInt(m.group(1)), Integer.parseInt(m.group(2)) - 1,
                    Integer.parseInt(m.group(3)), Integer.parseInt(m.group(4)),
                    Integer.parseInt(m.group(5)), Integer.parseInt(m.group(6)));

            /*
             * if 7th group is matched then we have UTC offset information
             * included
             */
            if (m.group(7) != null) {
                int ohh = Integer.parseInt(m.group(9));
                int omm = Integer.parseInt(m.group(10));

                /* time zone offset is specified in miliseconds */
                int offset = (ohh * 60 + omm) * 60 * 1000;

                if (m.group(8).equals("-")) {
                    offset = -offset;
                }

                TimeZone tz = TimeZone.getTimeZone("UTC");
                tz.setRawOffset(offset);

                cal.setTimeZone(tz);
            }

            mDate = cal.getTime();
        }
    }

    public ObexTime(Date date) {
        mDate = date;
    }

    public Date getTime() {
        return mDate;
    }

    @Override
    public String toString() {
        if (mDate == null) {
            return null;
        }

        Calendar cal = Calendar.getInstance();
        cal.setTime(mDate);

        /* note that months are numbered stating from 0 */
        return String.format(Locale.US, "%04d%02d%02dT%02d%02d%02d",
                cal.get(Calendar.YEAR), cal.get(Calendar.MONTH) + 1,
                cal.get(Calendar.DATE), cal.get(Calendar.HOUR_OF_DAY),
                cal.get(Calendar.MINUTE), cal.get(Calendar.SECOND));
    }
}
