package eu.dnetlib.data.claimsDemo;

import org.apache.log4j.Logger;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathFactory;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;

/**
 * Created by argirok on 20/11/2015.
 */
/*
*Search and Parsing xmls from Search Service
*Search for DOIs
*
 */
public class SearchUtils {
    private static final Logger logger = Logger.getLogger(SearchUtils.class);

    private static String searchUrl="http://beta.services.openaire.eu:8480/search/search?action=search";
//    private static String searchUrl="http://services.openaire.eu:8480/search/search?action=search";
    private static String apiUrlForResults=" http://beta.services.openaire.eu:8480/search/api/";//"http://api.openaire.eu/search/";
    private static String apiUrlForDedupResults="http://rudie.di.uoa.gr:8080/dnet-functionality-services-1.2.0-SNAPSHOT/api/";
    private static String apiUrlForProjects="http://beta.services.openaire.eu:8480/search/api/";//"http://rudie.di.uoa.gr:8080/dnet-functionality-services-1.2.0-SNAPSHOT/api/";
    private static String crossrefUrl="https://api.crossref.org/works?filter=doi:";
    private static String dataciteUrl="https://data.datacite.org/application/rdf+xml/";
    private static String dataciteNewAPIUrl="https://api.datacite.org/works/";
    private static String orcidUrlPrefix="https://pub.orcid.org/";
    private static String orcidUrlSuffix="/orcid-works";
    private boolean useApi=true;

    public SearchUtils(){

    }

    public static String fetchProjectXmlFromIndex(String id) throws Exception{
            return getRequest(getProjectApiUrl(id));
    }

    /**
     *Look up in API, if there is no result,
     * consider that id is a dedup id and search for the objIdentifier id.
     * Then look up again in the API with the objIdentifier
     * @param id
     * @return xml or null
     * @throws Exception
     */
    public static String fetchPublicationXmlFromIndex(String id) throws Exception{

        String xml=getRequest(getPublicationApiUrl(id));
        if(getNumberOfResultsInAPIXML(xml)==0){
            String objId=getResultObjIdentifierFromSearch(id);
            if(objId!=null){
                xml=getRequest(getPublicationApiUrl(objId));
                if(getNumberOfResultsInAPIXML(xml)==0){
                    xml=null;
                }
            }else{
                xml=null;
            }
        }
        return xml;
    }
    public static String fetchDedupPublicationXmlFromIndex(String id) throws Exception{

        String xml=getRequest(getDedupPublicationApiUrl(id));
        if(getNumberOfResultsInAPIXML(xml)==0){
            String objId=getResultObjIdentifierFromSearch(id);
            if(objId!=null){
                xml=getRequest(getDedupPublicationApiUrl(objId));
                if(getNumberOfResultsInAPIXML(xml)==0){
                    xml=null;
                }
            }else{
                xml = null;
            }
        }
        return xml;
    }

    /**
     *Look up in API, if there is no result,
     * consider that id is a dedup id and search for the objIdentifier id.
     * Then look up again in the API with the objIdentifier
     *
     * @param id
     * @return xml
     * @throws Exception
     */
    public static String fetchDatasetXmlFromIndex(String id) throws Exception{

        String xml=getRequest(getDatasetApiUrl(id));
        if(getNumberOfResultsInAPIXML(xml)==0){
            String objId=getResultObjIdentifierFromSearch(id);
            if(objId!=null){
                xml=getRequest(getDatasetApiUrl(objId));
                if(getNumberOfResultsInAPIXML(xml)==0){
                    xml=null;
                }
            }else{
                xml=null;
            }
        }
        return xml;

    }
    public static String fetchDedupDatasetXmlFromIndex(String id) throws Exception{

        String xml=getRequest(getDedupDatasetApiUrl(id));
        if(getNumberOfResultsInAPIXML(xml)==0){
            String objId=getResultObjIdentifierFromSearch(id);
            if(objId!=null){
                xml=getRequest(getDedupDatasetApiUrl(objId));
                if(getNumberOfResultsInAPIXML(xml)==0){
                    xml=null;
                }
            }else{
                xml = null;
            }
        }
        return xml;

    }

    public static String fetchResultXMLFromDatacite(String id) throws Exception{
            return getRequest(getDataciteUrl(id));
    }
    public static String fetchResultXMLFromOrcid(String id) throws Exception{

            return getRequest(getOrcidUrl(id));
    }

     public static String getProjectApiUrl(String id)  {

        return apiUrlForProjects+"/projects?openaireProjectID="+id;
    }

    public static String getDatasetApiUrl(String id)  {

        return apiUrlForResults+"/datasets?openaireDatasetID="+id;
    }
    public static String getDedupDatasetApiUrl(String id)  {

        return apiUrlForDedupResults+"/datasets?openaireDatasetID="+id;
    }
    public static String getPublicationApiUrl(String id)  {

        return apiUrlForResults+"/publications?openairePublicationID="+id;
    }
    public static String getDedupPublicationApiUrl(String id)  {

        return apiUrlForDedupResults+"/publications?openairePublicationID="+id;
    }
    private static String getDataciteUrl(String id)  {

        return dataciteNewAPIUrl+id;
    }

    private static String getOrcidUrl(String id)  {

        return orcidUrlPrefix+id+orcidUrlSuffix;
    }


    /**
     * Get result and objIdentifier  form openaire Search
     * @param resultdupid
     * @return
     */
    private static String getResultXMLByResultdupidSearchByUrl(String resultdupid)  {
        String url= null;
        try {
             url = searchUrl+"&sTransformer=results_openaire&query="+
                    URLEncoder.encode("(((deletedbyinference = false) AND (oaftype exact result)) )" +
                            " and (resultdupid exact " + resultdupid + ")", "UTF-8")
                    +"&size=10&locale=en_GB";
        } catch (UnsupportedEncodingException e) {
            logger.error("UnsupportedEncodingException",e);
        }
        return url;
    }


    // HTTP GET request
    private static String getRequest(String url) throws Exception {
        URL obj = new URL(url);
        HttpURLConnection con = (HttpURLConnection) obj.openConnection();
        int responseCode = con.getResponseCode();
        if(responseCode != 200){
            return null;
        }
        BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
        StringBuffer response = new StringBuffer();
        String inputLine;
        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine).append("\n");
        }
        in.close();
        return response.toString();
    }

    public static String getCrossrefJsonRecord(String doi){
        String url=crossrefUrl+doi;
        URL obj = null;
        String responseStr=null;
        try {
            obj = new URL(url);
            HttpURLConnection con = (HttpURLConnection) obj.openConnection();
            BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
            StringBuffer response = new StringBuffer();
            String inputLine;
            while ((inputLine = in.readLine()) != null) {
                response.append(inputLine).append("\n");
            }
            in.close();
            responseStr=response.toString();
            if(responseStr==null||(!responseStr.contains("\"status\":\"ok\"")||!(responseStr.contains("\"DOI\":\"")))){
                responseStr=null;
            }
        } catch (Exception e) {
            try{
                PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("dois_malformed_urls.txt", true)));
                out.println("Doi:"+doi+" Url:"+url);
                out.close();

            }catch (IOException e1) {
                logger.error("Couldn't write to file " + "dois_malformed_urls.txt",e);
            }

        }
        return responseStr;
    }

    /**
     *
     * @param doi
     * @return true  if the given doi request returns a valid answer otherwise false
     * @throws IOException
     */
     public static boolean isDoiValid(String doi) throws IOException {
            boolean found=false;
            String responseStr=getCrossrefJsonRecord(doi);
             if(responseStr!=null){
                found=true;
            }
            return found;
    }

    /**
     * Search in index for result with resultdupid
     * @param  resultdupid  Openaire Id
     * @return objIdentifier
     */
    private static String getResultObjIdentifierFromSearch(String resultdupid) throws Exception {
        String xml=getRequest(getResultXMLByResultdupidSearchByUrl(resultdupid));
        String objIdentifier=null;
            String size=null;
            DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
            InputSource inputSource= new InputSource(new StringReader(xml));
            Document document=dBuilder.parse(inputSource);
             XPathFactory xPathfactory= XPathFactory.newInstance();
            XPath xpath = xPathfactory.newXPath();
            NodeList nl = (NodeList) xpath.compile("//total/text()").evaluate(document, XPathConstants.NODESET);
            if (nl.getLength() > 0) {
                size= nl.item(0).getNodeValue();
            }
            if(size!=null && Integer.parseInt(size)>0){
                nl = (NodeList) xpath.compile("//field[@indexId='objIdentifier']/@value").evaluate(document, XPathConstants.NODESET);
                if (nl.getLength() > 0) {
                    objIdentifier=nl.item(0).getNodeValue();
                }
            }
        return objIdentifier;
    }

    /**
     *
     * @param xml : API result xml
     * @return number of results Found
     * @throws Exception
     */
    public static Integer getNumberOfResultsInAPIXML(String xml) throws Exception {
        if(xml==null){
            return 0;
        }
        String totalStr=null;
        Integer total=0;
        DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
        InputSource inputSource= new InputSource(new StringReader(xml));
        Document document=dBuilder.parse(inputSource);
        XPathFactory xPathfactory= XPathFactory.newInstance();
        XPath xpath = xPathfactory.newXPath();
        NodeList nl = (NodeList) xpath.compile("//total/text()").evaluate(document, XPathConstants.NODESET);
        if (nl.getLength() > 0) {
            totalStr= nl.item(0).getNodeValue();
        }
        if(totalStr!=null){
            total=Integer.parseInt(totalStr);
        }
        return total;
    }


}