/*
 * 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 org.jdbi.v3.postgres;

import java.lang.reflect.Type;
import java.math.BigDecimal;
import java.time.Duration;
import java.util.Optional;

import org.jdbi.v3.core.config.ConfigRegistry;
import org.jdbi.v3.core.mapper.ColumnMapper;
import org.jdbi.v3.core.mapper.ColumnMapperFactory;
import org.postgresql.util.PGInterval;

A column mapper which maps Postgres's PGInterval type to Java's Duration. 
 Not all PGIntervals are representable as Durations. E.g., one with months, which is an estimated ChronoUnit, or one whose seconds is larger than a long. An IllegalArgumentException will be thrown in either case. /**
 * A column mapper which maps Postgres's {@link PGInterval} type to Java's {@link Duration}.
 *
 * <p>
 * Not all {@link PGInterval}s are representable as {@link Duration}s. E.g., one with months, which is an
 * <em>estimated</em> {@link java.time.temporal.ChronoUnit}, or one whose seconds is larger than a {@code long}. An
 * {@link IllegalArgumentException} will be thrown in either case.
 */
public class DurationColumnMapperFactory implements ColumnMapperFactory {
    @Override
    public Optional<ColumnMapper<?>> build(Type type, ConfigRegistry config) {
        if (type != Duration.class) {
            return Optional.empty();
        }
        return Optional.of((r, i, c) -> {
            final Object obj = r.getObject(i);
            if (obj == null) {
                return null;
            }
            if (!(obj instanceof PGInterval)) {
                throw new IllegalArgumentException(String.format("got non-pginterval %s", obj));
            }
            final PGInterval interval = (PGInterval) obj;
            if (interval.getYears() != 0 || interval.getMonths() != 0) {
                throw new IllegalArgumentException(
                        String.format("pginterval \"%s\" not representable as duration", interval.getValue()));
            }
            final double seconds = interval.getSeconds();
            if (seconds > Long.MAX_VALUE || seconds < Long.MIN_VALUE) {
                throw new IllegalArgumentException(
                        String.format("pginterval \"%s\" has seconds too extreme to represent as duration",
                                interval.getValue()));
            }
            final long secondsLong = (long) seconds;
            final long nanos = BigDecimal.valueOf(seconds)
                    .subtract(BigDecimal.valueOf(secondsLong))
                    .movePointRight(9)
                    .longValue();
            return Duration.ofDays(interval.getDays())
                    .plusHours(interval.getHours())
                    .plusMinutes(interval.getMinutes())
                    .plusSeconds(secondsLong)
                    .plusNanos(nanos);
        });
    }
}