/*
 * Copyright 2009-2013 by The Regents of the University of California
 * 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 from
 * 
 *     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 edu.uci.ics.pregelix.dataflow;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.nio.ByteBuffer;

import edu.uci.ics.hyracks.api.context.IHyracksTaskContext;
import edu.uci.ics.hyracks.api.dataflow.IOperatorNodePushable;
import edu.uci.ics.hyracks.api.dataflow.value.IRecordDescriptorProvider;
import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
import edu.uci.ics.hyracks.api.job.JobSpecification;
import edu.uci.ics.hyracks.dataflow.common.comm.io.FrameDeserializer;
import edu.uci.ics.hyracks.dataflow.std.base.AbstractSingleActivityOperatorDescriptor;
import edu.uci.ics.hyracks.dataflow.std.base.AbstractUnaryInputSinkOperatorNodePushable;
import edu.uci.ics.hyracks.dataflow.std.file.FileSplit;
import edu.uci.ics.hyracks.dataflow.std.file.IFileSplitProvider;
import edu.uci.ics.hyracks.dataflow.std.util.StringSerializationUtils;
import edu.uci.ics.pregelix.dataflow.std.base.IRecordDescriptorFactory;
import edu.uci.ics.pregelix.dataflow.std.base.IRuntimeHookFactory;

public class VertexWriteOperatorDescriptor extends AbstractSingleActivityOperatorDescriptor {
    private static final long serialVersionUID = 1L;
    private final FileSplit[] splits;
    private final IRuntimeHookFactory preHookFactory;
    private final IRuntimeHookFactory postHookFactory;
    private final IRecordDescriptorFactory inputRdFactory;

    public VertexWriteOperatorDescriptor(JobSpecification spec, IRecordDescriptorFactory inputRdFactory,
            IFileSplitProvider fileSplitProvider, IRuntimeHookFactory preHookFactory,
            IRuntimeHookFactory postHookFactory) {
        super(spec, 1, 0);
        this.splits = fileSplitProvider.getFileSplits();
        this.preHookFactory = preHookFactory;
        this.postHookFactory = postHookFactory;
        this.inputRdFactory = inputRdFactory;
    }

    @Override
    public IOperatorNodePushable createPushRuntime(final IHyracksTaskContext ctx,
            final IRecordDescriptorProvider recordDescProvider, final int partition, int nPartitions)
            throws HyracksDataException {
        IOperatorNodePushable op = new AbstractUnaryInputSinkOperatorNodePushable() {
            private RecordDescriptor rd0;
            private FrameDeserializer frameDeserializer;
            private PrintWriter outputWriter;

            @Override
            public void open() throws HyracksDataException {
                rd0 = inputRdFactory == null ? recordDescProvider.getInputRecordDescriptor(getActivityId(), 0)
                        : inputRdFactory.createRecordDescriptor(ctx);
                frameDeserializer = new FrameDeserializer(ctx.getFrameSize(), rd0);
                try {
                    outputWriter = new PrintWriter(new OutputStreamWriter(new FileOutputStream(splits[partition]
                            .getLocalFile().getFile())));
                    if (preHookFactory != null)
                        preHookFactory.createRuntimeHook().configure(ctx);
                } catch (IOException e) {
                    throw new HyracksDataException(e);
                }
            }

            @Override
            public void nextFrame(ByteBuffer frame) throws HyracksDataException {
                frameDeserializer.reset(frame);
                while (!frameDeserializer.done()) {
                    Object[] tuple = frameDeserializer.deserializeRecord();
                    // output the vertex
                    outputWriter.print(StringSerializationUtils.toString(tuple[tuple.length - 1]));
                    outputWriter.println();
                }
            }

            @Override
            public void fail() throws HyracksDataException {

            }

            @Override
            public void close() throws HyracksDataException {
                if (postHookFactory != null)
                    postHookFactory.createRuntimeHook().configure(ctx);
                outputWriter.close();
            }

        };
        return op;
    }
}