/*
 * Copyright 2009-2010 Yuichiro Moriguchi
 *
 * 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 net.morilib.lisp.datetime;

import java.util.List;

import net.morilib.lisp.Datum;
import net.morilib.lisp.Environment;
import net.morilib.lisp.LispMessage;
import net.morilib.lisp.LispSmallInt;
import net.morilib.lisp.LispUtils;
import net.morilib.lisp.Subr;

/**
 *
 *
 * @author MORIGUCHI, Yuichiro 2011/01/09
 */
public class ModifiedJulianDayToDate extends Subr {

	/* (non-Javadoc)
	 * @see net.morilib.lisp.Subr#eval(net.morilib.lisp.Datum, net.morilib.lisp.Environment, net.morilib.lisp.LispMessage)
	 */
	@Override
	public Datum eval(Datum body, Environment env, LispMessage mesg) {
		List<Datum> l = LispUtils.consToList(body, mesg);

		if(l.size() < 1 || l.size() > 2) {
			throw mesg.getError("err.argument", body);
		} else if(!(l.get(0) instanceof LispModifiedJulianDay)) {
			throw mesg.getError(
					"err.srfi19.require.modifiedjulianday", l.get(0));
		} else if(l.size() == 1) {
			return new LispDate(
					((LispModifiedJulianDay)l.get(0)).getJulianDay());
		} else if(l.get(1) instanceof LispSmallInt) {
			return new LispDate(
					((LispModifiedJulianDay)l.get(0)).getJulianDay(),
					l.get(1).getInt());
		} else {
			throw mesg.getError("err.require.smallint", l.get(1));
		}

	}

}
