/*
 * 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.r6rs.io;

import java.io.ByteArrayInputStream;
import java.io.IOException;

import net.morilib.lisp.ConsIterator;
import net.morilib.lisp.Datum;
import net.morilib.lisp.Environment;
import net.morilib.lisp.LispBoolean;
import net.morilib.lisp.LispMessage;
import net.morilib.lisp.Subr;
import net.morilib.lisp.r6rs.io.transcd.ILispTranscoder;
import net.morilib.lisp.subr.SubrUtils;
import net.morilib.lisp.uvector.ILispBytevector;
import net.morilib.util.Iterators;

/**
 *
 *
 * @author MORIGUCHI, Yuichiro 2012/01/03
 */
public class OpenBytevectorInputPort 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) {
		ConsIterator itr = new ConsIterator(body);
		Datum bv = SubrUtils.nextIf(itr, mesg, body);
		Datum tr = Iterators.nextIf(itr, LispBoolean.FALSE);

		SubrUtils.checkTerminated(itr, body, mesg);
		if(!(bv instanceof ILispBytevector)) {
			throw mesg.getError("err.uvector.require.8", bv);
		} else if(tr.isTrue() && !(tr instanceof ILispTranscoder)) {
			throw mesg.getError("err.io.require.transcoder", tr);
		} else if(tr.isTrue()) {
			try {
				return (Datum)((ILispTranscoder)tr).newInput(
						new ByteArrayInputStream(
								((ILispBytevector)bv).toBytes()));
			} catch (IOException e) {
				throw mesg.getError("err.io", e.getMessage());
			}
		} else {
			return new LispByteArrayBinaryInputPort(
					((ILispBytevector)bv).toBytes());
		}
	}

}
