package net.sf.jabref.imports;

 import net.sf.jabref.BibtexEntry;

 import net.sf.jabref.GUIGlobals;

 import net.sf.jabref.Globals;

 import net.sf.jabref.OutputPrinter;

 import net.sf.jabref.net.URLDownload;

 import javax.swing.*;

 import java.io.IOException;

 import java.io.UnsupportedEncodingException;

 import java.net.URL;

 import java.net.URLEncoder;

 import java.util.ArrayList;

 import java.util.List;

 import java.util.regex.Matcher;

 import java.util.regex.Pattern;

 public class ScienceDirectFetcher implements EntryFetcher {

     protected static int MAX_PAGES_TO_LOAD = 8;

     protected static final String WEBSITE_URL = "http://www.sciencedirect.com";

     protected static final String SEARCH_URL = WEBSITE_URL +"/science/quicksearch?query=";

     protected static final String linkPrefix = "http://www.sciencedirect.com/science?_ob=ArticleURL&" ;

     protected static final Pattern linkPattern = Pattern.compile(

             "<a href=\""+

             linkPrefix.replaceAll("\\?", "\\\\?")+

             "([^\"]+)\"\"");

     protected static final Pattern nextPagePattern = Pattern.compile(

             "<a href=\"(.*)\">Next &gt;");

     protected boolean stopFetching = false;

     protected boolean noAccessFound = false;

     public String getHelpPage() {

         return "ScienceDirect.html";

     }

     public URL getIcon() {

         return GUIGlobals.getIconUrl("www");

     }

     public String getKeyName() {

         return "Search ScienceDirect";

     }

     public JPanel getOptionsPanel() {

         // No Options panel

         return null;

     }

     public String getTitle() {

         return Globals.menuTitle("Search ScienceDirect");

     }

     public void stopFetching() {

         stopFetching = true;

         noAccessFound = false;

     }

     public boolean processQuery(String query, ImportInspector dialog, OutputPrinter status) {

         stopFetching = false;

         try {

             List<String> citations = getCitations(query);

             if (citations == null)

                 return false;

             if (citations.size() == 0){

                 status.showMessage(Globals.lang("No entries found for the search string '%0'",

                     query),

                     Globals.lang("Search ScienceDirect"), JOptionPane.INFORMATION_MESSAGE);

                 return false;

             }

             int i=0;

             for (String cit : citations) {

                 if (stopFetching)

                     break;

                 BibtexEntry entry = BibsonomyScraper.getEntry(cit);

                 if (entry != null)

                     dialog.addEntry(entry);

                 dialog.setProgress(++i, citations.size());

             }

             return true;

         } catch (IOException e) {

             e.printStackTrace();

             status.showMessage(Globals.lang("Error while fetching from ScienceDirect") + ": " + e.getMessage());

         }

         return false;

     }

     /**

      *

      * @param query

      *            The search term to query JStor for.

      * @return a list of IDs

      * @throws java.io.IOException

      */

     protected List<String> getCitations(String query) throws IOException {

         String urlQuery;

         ArrayList<String> ids = new ArrayList<String>();

         try {

             urlQuery = SEARCH_URL + URLEncoder.encode(query, "UTF-8");

             int count = 1;

             String nextPage = null;

             while (((nextPage = getCitationsFromUrl(urlQuery, ids)) != null)

                     && (count < MAX_PAGES_TO_LOAD)) {

                 urlQuery = nextPage;

                 count++;

             }

             return ids;

         } catch (UnsupportedEncodingException e) {

             throw new RuntimeException(e);

         }

     }

     protected String getCitationsFromUrl(String urlQuery, List<String> ids) throws IOException {

         URL url = new URL(urlQuery);

         URLDownload ud = new URLDownload(url);

         ud.download();

         String cont = ud.getStringContent();

         //String entirePage = cont;

         Matcher m = linkPattern.matcher(cont);

         if (m.find()) {

             while (m.find()) {

                 ids.add(linkPrefix+m.group(1));

                 cont = cont.substring(m.end());

                 m = linkPattern.matcher(cont);

             }

         }

         else {

             return null;

         }

         /*m = nextPagePattern.matcher(entirePage);

         if (m.find()) {

             String newQuery = WEBSITE_URL +m.group(1);

             return newQuery;

         }

         else*/

             return null;

     }

 }