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

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import eu.dnetlib.data.collector.ThreadSafeIterator;
import eu.dnetlib.rmi.data.CollectorServiceRuntimeException;
import org.apache.commons.io.IOUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.http.HttpStatus;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.lang.reflect.Type;
import java.util.List;

public class ThanadosIterator extends ThreadSafeIterator {

	private static final Log log = LogFactory.getLog(ThanadosIterator.class);
	private final CloseableHttpClient client = HttpClients.createDefault();

	private String baseUrl;
	private String currentLine;
	private List<String> identifiers;
	private int counter = 0;
	private String urlFormat = "%s/%s?format=xml";

	public ThanadosIterator(final String baseUrl, final String listAddress) {
		try {
			this.baseUrl = baseUrl;
			this.identifiers = downloadIdentifierList(listAddress);
			this.counter = 0;
		} catch (Exception e) {
			throw new CollectorServiceRuntimeException("Error creating iterator", e);
		}
	}

	@Override
	public boolean doHasNext() {
		return counter <= this.identifiers.size();
	}

	@Override
	public String doNext() {
		try {
			if (counter <= this.identifiers.size()) {
				String toDownload = String.format(urlFormat, baseUrl, identifiers.get(counter));
				log.debug("Downloading "+toDownload);
				return download(toDownload);
			} else {
				throw new CollectorServiceRuntimeException("Iterator has reached the end");
			}
		} finally {
				counter++;
		}
	}

	protected List<String> downloadIdentifierList(final String listUrl) {

		String list = download(listUrl);
		Gson converter = new Gson();
		Type type = new TypeToken<List<String>>(){}.getType();
		return converter.fromJson(list, type );

	}

	private String download(final String url) {
		log.debug("download:  "+url);
		final HttpGet method = new HttpGet(url);

		try(CloseableHttpResponse response = client.execute(method)) {
			int statusCode = response.getStatusLine().getStatusCode();

			if (HttpStatus.SC_OK == statusCode) {
				return IOUtils.toString(new BufferedInputStream(response.getEntity().getContent()), "utf-8");
			} else {
				throw new CollectorServiceRuntimeException("Error " + statusCode + " dowloading url: " + url);
			}

		} catch (IOException e) {
			throw new CollectorServiceRuntimeException("Error downloading url: " + url);
		}
	}


	public List<String> getIdentifiers() {
		return identifiers;
	}

	public void setIdentifiers(List<String> identifiers) {
		this.identifiers = identifiers;
	}
}