package eu.dnetlib.data.collector.plugins.ariadneplus.ads;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Iterator;

import com.google.common.collect.Lists;
import com.ximpleware.*;
import eu.dnetlib.data.collector.ThreadSafeIterator;
import eu.dnetlib.rmi.data.CollectorServiceRuntimeException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class ADSIterator extends ThreadSafeIterator {

	private static final Log log = LogFactory.getLog(ADSIterator.class);

	private Iterator<String> iterator;
	
	public ADSIterator(final Iterator<String> recordIterator){
		this.iterator = recordIterator;
	}

	@Override
	public boolean doHasNext() {
		return iterator.hasNext();
	}

	@Override
	public String doNext()  {
		String record = iterator.next();
		try {
			return addADSNamespace(record);
		} catch (Exception e) {
			log.warn("Skipping record because of exception "+e);
			log.debug("Skipped record: "+record);
			if(this.hasNext()){
				return this.next();
			}
			else return "";
		}
	}

	protected String addADSNamespace(final String xml) {
		
		String namespaceList = " xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:dc=\"http://purl.org/dc/elements/1.1/\"\n" + 
				"    xmlns:dcterms=\"http://purl.org/dc/terms/\"\n" + 
				"    xmlns:ads=\"https://archaeologydataservice.ac.uk/\"";
		try {
	        VTDGen vg = new VTDGen();
	        vg.setDoc(xml.getBytes());
	        vg.parse(false); // namespace unaware to all name space nodes addressable using xpath @*
	        VTDNav vn = vg.getNav();
	        XMLModifier xm = new XMLModifier(vn);
	        
	        byte[] attrBytes = namespaceList.getBytes();
	        
	        vn.toElement(VTDNav.ROOT);
	        xm.insertAttribute(attrBytes);
	        ByteArrayOutputStream baos = new ByteArrayOutputStream();
	        xm.output(baos);
	        return baos.toString();
		} catch(ParseException | ModifyException | NavException | IOException | TranscodeException e){
			log.error("Cannot add namespace declarations to element: "+xml);
			throw new CollectorServiceRuntimeException("Cannot add namespace declarations to element", e);
		}
	}
	
	public Iterator<String> getIterator() {
		return iterator;
	}

	public void setIterator(final Iterator<String> iterator) {
		this.iterator = iterator;
	}

}