001/*
002 * Copyright © 2025 CUI-OpenSource-Software (info@cuioss.de)
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package de.cuioss.test.generator.internal.net.java.quickcheck.generator.support;
017
018import de.cuioss.test.generator.internal.net.java.quickcheck.Generator;
019
020import java.util.Calendar;
021import java.util.Date;
022import java.util.concurrent.TimeUnit;
023
024import static java.lang.Math.signum;
025
026public class DateGenerator implements Generator<Date> {
027
028    private final VetoableGenerator<Long> generator;
029
030    public DateGenerator(TimeUnit precision, long low, long high, int tries) {
031        generator = new VetoableGenerator<>(new MillisGenerator(precision, low, high), tries) {
032
033            @Override
034            protected boolean tryValue(Long value) {
035                return value != null;
036            }
037        };
038    }
039
040    @Override
041    public Date next() {
042        return new Date(generator.next());
043    }
044
045    private static class MillisGenerator implements Generator<Long> {
046
047        private final TimeUnit precision;
048        private final LongGenerator times;
049        private final long low;
050        private final long high;
051
052        public MillisGenerator(TimeUnit precision, long low, long high) {
053            this.precision = precision;
054            this.times = new LongGenerator(low, high);
055            this.low = low;
056            this.high = high;
057        }
058
059        @Override
060        public Long next() {
061            Long millis = times.next();
062            Calendar time = Calendar.getInstance();
063            time.setTimeInMillis(millis);
064            switch (precision) {
065                case DAYS:
066                    time.set(Calendar.HOUR, 0); //$FALL-THROUGH$
067                case HOURS:
068                    time.set(Calendar.MINUTE, 0); //$FALL-THROUGH$
069                case MINUTES:
070                    time.set(Calendar.SECOND, 0); //$FALL-THROUGH$
071                case SECONDS:
072                    time.set(Calendar.MILLISECOND, 0); //$FALL-THROUGH$
073                default:
074            }
075            long correctedMillis = time.getTimeInMillis();
076            return isOutOffBounds(correctedMillis) || isOverflow(millis, correctedMillis) ? null : correctedMillis;
077        }
078
079        private boolean isOutOffBounds(long correctedMillis) {
080            return correctedMillis < low || correctedMillis > high;
081        }
082
083        // TODO define this differently (signum changes near 0 without overflow)
084        private boolean isOverflow(long millis, long correctedMillis) {
085            return signum(correctedMillis) != signum(millis);
086        }
087
088        @Override
089        public String toString() {
090            return "%s[low=%s, high=%s, precision=%s".formatted(getClass().getSimpleName(), low, high, precision);
091        }
092
093    }
094}