Dépôt officiel du code source de l'ERP OpenConcerto

/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

 *

 * Copyright 2011 OpenConcerto, by ILM Informatique. All rights reserved.

 *

 * The contents of this file are subject to the terms of the GNU General Public License Version 3

 * only ("GPL"). You may not use this file except in compliance with the License. You can obtain a

 * copy of the License at http://www.gnu.org/licenses/gpl-3.0.html See the License for the specific

 * language governing permissions and limitations under the License.

 *

 * When distributing the software, include this License Header Notice in each file.

 */

 package org.openconcerto.openoffice;

import org.openconcerto.utils.TimeUtils;

import java.math.BigDecimal;

import java.math.BigInteger;

import java.math.MathContext;

import java.text.DateFormat;

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.util.Calendar;

import java.util.LinkedHashMap;

import java.util.Map;

import java.util.TimeZone;

import javax.xml.datatype.DatatypeConstants;

import javax.xml.datatype.Duration;

/**

 * The null date of an OpenDocument.

 */

public final class ODEpoch {

    static private final BigDecimal MS_PER_DAY = BigDecimal.valueOf(24l * 60l * 60l * 1000l);

    static private final DateFormat DATE_FORMAT;

    static private final ODEpoch DEFAULT_EPOCH;

    static private final Map<String, ODEpoch> cache = new LinkedHashMap<String, ODEpoch>(4, 0.75f, true) {

        @Override

        protected boolean removeEldestEntry(Map.Entry<String, ODEpoch> eldest) {

            return this.size() > 16;

        }

    };

    static {

        DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd");

        DATE_FORMAT.setCalendar(Calendar.getInstance(TimeZone.getTimeZone("UTC")));

        try {

            DEFAULT_EPOCH = new ODEpoch("1899-12-30");

        } catch (ParseException e) {

            // shouldn't happen since string are constants

            throw new IllegalStateException(e);

        }

    }

    static public final ODEpoch getDefaultEpoch() {

        return DEFAULT_EPOCH;

    }

    static public final ODEpoch getInstance(String date) throws ParseException {

        if (date == null || date.equals(DEFAULT_EPOCH.getDateString())) {

            return DEFAULT_EPOCH;

        } else {

            ODEpoch res = cache.get(date);

            if (res == null) {

                res = new ODEpoch(date);

                cache.put(date, res);

            }

            return res;

        }

    }

    static private final Calendar parse(final String date) throws ParseException {

        final Calendar cal = (Calendar) DATE_FORMAT.getCalendar().clone();

        cal.setTime(DATE_FORMAT.parse(date));

        return cal;

    }

    private final String dateString;

    private final Calendar epochUTC;

    private ODEpoch(final String date) throws ParseException {

        this.dateString = date;

        this.epochUTC = parse(date);

        assert this.epochUTC.getTimeZone().equals(DATE_FORMAT.getTimeZone());

    }

    public final String getDateString() {

        return this.dateString;

    }

    public final Calendar getCalendar() {

        return (Calendar) this.epochUTC.clone();

    }

    private final Calendar getDate(final Duration duration) {

        // If we don't use the UTC calendar, we go from 0:00 (the epoch), we add n days, we get

        // to the last Sunday of March at 0:00, so far so good, but then we add say 10 hours, thus

        // going through the change of offset, and arriving at 11:00.

        final Calendar res = getCalendar();

        duration.addTo(res);

        return res;

    }

    public final Duration normalizeToDays(final Duration dur) {

        final Duration res = dur.getYears() == 0 && dur.getMonths() == 0 ? dur : getDuration(getDays(dur));

        assert res.getYears() == 0 && res.getMonths() == 0;

        return res;

    }

    public final Duration normalizeToHours(final Duration dur) {

        final Duration durationInDays = normalizeToDays(dur);

        final BigInteger days = (BigInteger) durationInDays.getField(DatatypeConstants.DAYS);

        if (days == null || days.equals(BigInteger.ZERO))

            return durationInDays;

        final BigInteger hours = ((BigInteger) durationInDays.getField(DatatypeConstants.HOURS)).add(days.multiply(BigInteger.valueOf(24)));

        return TimeUtils.getTypeFactory().newDuration(days.signum() >= 0, BigInteger.ZERO, BigInteger.ZERO, BigInteger.ZERO, hours, (BigInteger) durationInDays.getField(DatatypeConstants.MINUTES),

                (BigDecimal) durationInDays.getField(DatatypeConstants.SECONDS));

    }

    public final BigDecimal getDays(final Duration duration) {

        return getDays(getDate(duration));

    }

    public final BigDecimal getDays(final Calendar cal) {

        // can't use Duration.normalizeWith() since it doesn't handle DST, i.e. going from winter to

        // summer at midnight will miss a day

        final long diff = TimeUtils.normalizeLocalTime(cal) - this.epochUTC.getTimeInMillis();

        return BigDecimal.valueOf(diff).divide(MS_PER_DAY, MathContext.DECIMAL128);

    }

    public final Calendar getDate(final BigDecimal days) {

        return getDate(days, Calendar.getInstance());

    }

    public final Calendar getDate(final BigDecimal days, final Calendar res) {

        final Calendar utcCal = getDate(getDuration(days));

        // can't use getTimeZone().getOffset() since we have no idea for the UTC time

        return TimeUtils.copyLocalTime(utcCal, res);

    }

    private final static Duration getDuration(final BigDecimal days) {

        final BigDecimal posDays = days.abs();

        final BigInteger wholeDays = posDays.toBigInteger().abs();

        final BigDecimal hours = posDays.subtract(new BigDecimal(wholeDays)).multiply(BigDecimal.valueOf(24));

        final BigInteger wholeHours = hours.toBigInteger();

        final BigDecimal minutes = hours.subtract(new BigDecimal(wholeHours)).multiply(BigDecimal.valueOf(60));

        final BigInteger wholeMinutes = minutes.toBigInteger();

        // round to 16 digits, i.e. 10^-14 seconds is more than enough

        // it is required since the number coming from getDays() might have been rounded

        final BigDecimal seconds = minutes.subtract(new BigDecimal(wholeMinutes)).multiply(BigDecimal.valueOf(60)).round(MathContext.DECIMAL64);

        return TimeUtils.getTypeFactory().newDuration(days.signum() >= 0, BigInteger.ZERO, BigInteger.ZERO, wholeDays, wholeHours, wholeMinutes, seconds);

    }

}