/*******************************************************************************
 * Copyright (c) 2015-2018 Skymind, Inc.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Apache License, Version 2.0 which is available at
 * https://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.
 *
 * SPDX-License-Identifier: Apache-2.0
 ******************************************************************************/

package org.datavec.local.transforms.functions.data;


import org.datavec.api.records.reader.SequenceRecordReader;
import org.datavec.api.writable.BytesWritable;
import org.datavec.api.writable.Text;
import org.datavec.api.writable.Writable;
import org.nd4j.linalg.function.Function;
import org.nd4j.linalg.primitives.Pair;

import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.net.URI;
import java.util.List;

/**SequenceRecordReaderBytesFunction: Converts binary data (in the form of a BytesWritable) to DataVec format data
 * ({@code List<List<<Writable>>}) using a SequenceRecordReader
 * @author Alex Black
 */
public class SequenceRecordReaderBytesFunction implements Function<Pair<Text, BytesWritable>, List<List<Writable>>> {

    private final SequenceRecordReader recordReader;

    public SequenceRecordReaderBytesFunction(SequenceRecordReader recordReader) {
        this.recordReader = recordReader;
    }

    @Override
    public List<List<Writable>> apply(Pair<Text, BytesWritable> v1) {
        URI uri = URI.create(v1.getFirst().toString());
        DataInputStream dis = new DataInputStream(new ByteArrayInputStream(v1.getRight().getContent()));
        try {
            return recordReader.sequenceRecord(uri, dis);
        } catch (IOException e) {
            throw new IllegalStateException(e);
        }

    }
}
