/**
    * This file Copyright (c) 2008-2015 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.module.rssaggregator.util;
  
  import info.magnolia.context.MgnlContext;
  
  import java.util.Collection;
  import java.util.List;
  
  import javax.jcr.Node;
  import javax.jcr.RepositoryException;
  
  import org.apache.commons.lang3.StringEscapeUtils;
  import org.apache.commons.lang3.StringUtils;
  
  
  /**
   * Copy of the STK Pager to avoid cyclic dependencies.
   * Will be replaced by infinite scroll in a later version.
   */
  public class PagerUtil {
  
      private int count;
      private String link;
      private int maxResultsPerPage;
      private Collection items;
      private String position;
  
      public PagerUtil(String link, Collection items, Node content) {
          this.count = items.size();
          this.items = items;
          this.link = link;
  
          getPagerProperties(content);
      }
  
      protected PagerUtil() {
      }
  
      protected void setResults(int maxResultsPerPage) {
          this.maxResultsPerPage = maxResultsPerPage;
      }
  
      protected void setCount(int count) {
          this.count = count;
      }
  
      public Collection getPageItems() {
  
          Collection subList = items;
          int offset = getOffset();
          if (count > 0) {
              int limit = maxResultsPerPage + offset;
              if (items.size() < limit) {
                  limit = count;
              }
              subList = ((List) items).subList(offset, limit);
  
          }
          return subList;
      }
  
      protected int getOffset() {
          int offset = ((getCurrentPage() - 1) * maxResultsPerPage);
          if (offset > count) {
              int pages = count / maxResultsPerPage;
              offset = pages * maxResultsPerPage;
          }
         return offset;
     }
 
     public int getCurrentPage() {
         int currentPage = 1;
         if (MgnlContext.getParameter("currentPage") != null && (Integer.parseInt(MgnlContext.getParameter("currentPage")) > 1)) {
             currentPage = Integer.parseInt(MgnlContext.getParameter("currentPage"));
         }
         return currentPage;
     }
 
     public String getPageLink(int i) {
         String current = "currentPage=";
         if (this.link.indexOf('?') > 0) {
             final String query = StringUtils.substringAfter(this.link, "?");
             StringBuilder newQuery = new StringBuilder("?");
             String[] params = query.split("&");
             boolean pageSet = false;
             int cnt = 0;
             for (String param : params) {
                 if (param.startsWith(current)) {
                     newQuery.append(current).append(i);
                     pageSet = true;
                 } else {
                     newQuery.append(StringEscapeUtils.escapeHtml4(param)); //XSS without this escaping possible
                 }
                 cnt++;
                 if (cnt < params.length) {
                     newQuery.append("&");
                 }
             }
             if (!pageSet) {
                 if (newQuery.length() > 1) {
                     newQuery.append("&");
                 }
                 newQuery.append(current).append(i);
 
             }
             return StringUtils.substringBefore(this.link, "?") + newQuery.toString();
         } else {
             String link = this.link + "?" + current + i;
             return link;
         }
     }
 
     public int getNumPages() {
         int numPages = count / maxResultsPerPage;
         if ((count % maxResultsPerPage) > 0) {
             numPages++;
         }
         return numPages;
     }
 
     public int getBeginIndex() {
         if (getCurrentPage() - 2 <= 1) {
             return 1;
         } else {
             return getCurrentPage() - 2;
         }
     }
 
     public int getEndIndex() {
         if (getCurrentPage() + 2 >= getNumPages()) {
             return getNumPages();
         } else {
             return getCurrentPage() + 2;
         }
     }
 
     public String getPosition() {
         return position;
     }
 
     protected void getPagerProperties(Node content) {
 
         maxResultsPerPage = 10000;
         try {
             if (content.hasProperty("maxResultsPerPage")) {
                 int max = (int) content.getProperty("maxResultsPerPage").getLong();
                 if (max > 0) {
                     maxResultsPerPage = max;
                 }
             }
 
             position = "top";
             if (content.hasProperty("position")) {
                 position = content.getProperty("position").getString();
             }
 
         } catch (RepositoryException e) {
             //use defaults
         }
 
     }
 }