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package eu.dnetlib.oa.graph.datasetsusagestats.export;

import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import com.google.gson.JsonObject;
import java.util.ArrayList;
import java.util.Iterator;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.json.simple.parser.ParseException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 *
 * @author dpie
 */
public class DownloadReportsListFromDatacite {

    private String dataciteBaseURL;
    private String dataciteReportPath;
    private static final Logger logger = LoggerFactory.getLogger(UsageStatsExporter.class);

    public DownloadReportsListFromDatacite(String dataciteBaseURL, String dataciteReportPath) throws MalformedURLException, Exception {

        this.dataciteBaseURL = dataciteBaseURL;
        this.dataciteReportPath = dataciteReportPath;
    }

    public void downloadReportsList() throws ParseException {
        StringBuilder responseStrBuilder = new StringBuilder();

        Gson gson = new Gson();

        try {
            BufferedInputStream in = new BufferedInputStream(new URL(dataciteBaseURL).openStream());
            logger.info("Downloading from " + dataciteBaseURL);

            BufferedReader streamReader = new BufferedReader(new InputStreamReader(in, "UTF-8"));
            String inputStr;

            while ((inputStr = streamReader.readLine()) != null) {
                responseStrBuilder.append(inputStr);
            }
        } catch (IOException e) {
            logger.info(e.getMessage());
        }
        JsonObject jsonObject = gson.fromJson(responseStrBuilder.toString(), JsonObject.class);
        JsonArray dataArray = jsonObject.getAsJsonArray("reports");
        ArrayList reportsList = new ArrayList();
        for (JsonElement element : dataArray) {
            reportsList.add(element.getAsJsonObject().get("id").getAsString());
        }

        Iterator it = reportsList.iterator();
        while (it.hasNext()) {
            String reportId = it.next().toString();
            String url = dataciteBaseURL + reportId;

            try {
                BufferedInputStream in = new BufferedInputStream(new URL(url).openStream());
                BufferedReader streamReader = new BufferedReader(new InputStreamReader(in, "UTF-8"));
                String inputStr;
                StringBuilder responseStrBuilder2 = new StringBuilder();
                while ((inputStr = streamReader.readLine()) != null) {
                    responseStrBuilder2.append(inputStr);
                }
                FileSystem fs = FileSystem.get(new Configuration());
                FSDataOutputStream fin = fs.create(new Path(dataciteReportPath + "/" + reportId + ".json"),
                        true);
                byte[] jsonObjectRawBytes = responseStrBuilder2.toString().getBytes();
                fin.write(jsonObjectRawBytes);
                fin.writeChar('\n');

                fin.close();

                fin.close();
            } catch (IOException e) {
                System.out.println(e);
            }
        }
    }
}