/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.tuple;

import java.sql.Time;
import java.sql.Timestamp;
import java.time.Instant;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.MonthDay;
import java.time.OffsetDateTime;
import java.time.OffsetTime;
import java.time.Year;
import java.time.YearMonth;
import java.time.ZonedDateTime;
import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;

import org.hibernate.HibernateException;

/**
 * Generators for obtaining the current VM timestamp in different representations.
 *
 * @author Gunnar Morling
 */
/* package */ final class TimestampGenerators {

	private static final Map<Class<?>, ValueGenerator<?>> generators;

	private TimestampGenerators() {
	}

	static {
		generators = new HashMap<>();
		generators.put(
				Date.class,
				(session, owner) -> new Date()
		);
		generators.put(
				Calendar.class,
				(session, owner) -> {
					Calendar calendar = Calendar.getInstance();
					calendar.setTime( new Date() );
					return calendar;
				}
		);
		generators.put(
				java.sql.Date.class,
				(session, owner) -> new java.sql.Date( System.currentTimeMillis() )
		);

		generators.put(
				Time.class,
				(session, owner) -> new Time( System.currentTimeMillis() )
		);
		generators.put(
				Timestamp.class,
				(session, owner) -> new Timestamp( System.currentTimeMillis() )
		);
		generators.put(
				Instant.class,
				(session, owner) -> Instant.now()
		);
		generators.put(
				LocalDate.class,
				(session, owner) -> LocalDate.now()
		);
		generators.put(
				LocalDateTime.class,
				(session, owner) -> LocalDateTime.now()
		);
		generators.put(
				LocalTime.class,
				(session, owner) -> LocalTime.now()
		);
		generators.put(
				MonthDay.class,
				(session, owner) -> MonthDay.now()
		);
		generators.put(
				OffsetDateTime.class,
				(session, owner) -> OffsetDateTime.now()
		);
		generators.put(
				OffsetTime.class,
				(session, owner) -> OffsetTime.now()
		);
		generators.put(
				Year.class,
				(session, owner) -> Year.now()
		);
		generators.put(
				YearMonth.class,
				(session, owner) -> YearMonth.now()
		);
		generators.put(
				ZonedDateTime.class,
				(session, owner) -> ZonedDateTime.now()
		);
	}

	@SuppressWarnings("unchecked")
	public static <T> ValueGenerator<T> get(final Class<T> type) {
		final ValueGenerator<?> valueGeneratorSupplier = generators.get(
				type );
		if ( Objects.isNull( valueGeneratorSupplier ) ) {
			throw new HibernateException(
					"Unsupported property type [" + type.getName() + "] for @CreationTimestamp or @UpdateTimestamp generator annotation" );
		}

		return (ValueGenerator<T>) valueGeneratorSupplier;
	}
}