package org.easybatch.extensions.stream;

import org.easybatch.core.reader.RecordReader;
import org.easybatch.core.record.GenericRecord;
import org.easybatch.core.record.Header;
import org.easybatch.core.record.Record;

import java.util.Date;
import java.util.Iterator;
import java.util.stream.Stream;

/**
 * Reader that reads records form a {@link Stream}.
 *
 * This reader produces {@link GenericRecord} instances.
 *
 * @param <T> Type of elements in the stream.
 * @author Charles Fleury
 * @since 5.0
 */
public class StreamRecordReader<T> implements RecordReader {

    private static final String DEFAULT_DATASOURCE_NAME = "DATASOURCE";

    protected String datasource;
    protected Stream<T> stream;
    protected Iterator<T> iterator;
    protected long currentRecordNumber;

    /**
     * Create a {@link StreamRecordReader} to read record from a {@link Stream}.
     *
     * @param stream to read record from
     */
    public StreamRecordReader(final Stream<T> stream) {
        this(stream, DEFAULT_DATASOURCE_NAME);
    }

    /**
     * Create a {@link StreamRecordReader} to read record from a {@link Stream}.
     *
     * @param stream     to read record from
     * @param datasource name (default to DEFAULT_DATASOURCE_NAME)
     */
    public StreamRecordReader(final Stream<T> stream, final String datasource) {
        this.stream = stream;
        this.datasource = datasource;
    }

    /**
     * Open the reader.
     */
    @Override
    public void open() throws Exception {
        if (stream == null) {
            throw new IllegalArgumentException("stream must not be null");
        }

        if (datasource == null || datasource.isEmpty()) {
            datasource = DEFAULT_DATASOURCE_NAME;
        }

        currentRecordNumber = 0;
        iterator = stream.iterator();
    }

    /**
     * Read next record from the data source.
     *
     * @return the next record from the data source.
     */
    @Override
    public Record<T> readRecord() throws Exception {
        if (iterator.hasNext()) {
            Header header = new Header(++currentRecordNumber, datasource, new Date());
            return new GenericRecord<>(header, iterator.next());
        } else {
            return null;
        }
    }

    /**
     * Close the reader.
     */
    @Override
    public void close() throws Exception {
        stream.close();
    }
}

@@ -626,26 +626,32 @@
 NAME = %22
-DATASOURCE
+In-Memory Stream
 %22;%0A%0A    

rename default data source name to "In-Memory Stream" to be consistent with other readers