/*
    * Copyright (c) 2002-2022, City of Paris
    * All rights reserved.
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions
    * are met:
    *
    *  1. Redistributions of source code must retain the above copyright notice
   *     and the following disclaimer.
   *
   *  2. Redistributions in binary form must reproduce the above copyright notice
   *     and the following disclaimer in the documentation and/or other materials
   *     provided with the distribution.
   *
   *  3. Neither the name of 'Mairie de Paris' nor 'Lutece' nor the names of its
   *     contributors may be used to endorse or promote products derived from
   *     this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   * License 1.0
   */
  package fr.paris.lutece.util.html;
  
  import fr.paris.lutece.util.url.UrlItem;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.servlet.http.HttpServletRequest;
  
  /**
   * Abstract Paginator
   * 
   * @param <E>
   *            the type
   */
  public abstract class AbstractPaginator<E> implements IPaginator<E>
  {
      /** Default value for Page Index Parameter */
      public static final String PARAMETER_PAGE_INDEX = "page_index";
  
      /** Default value for Items Per Page Parameter */
      public static final String PARAMETER_ITEMS_PER_PAGE = "items_per_page";
      public static final String LABEL_FIRST = "|&lt;";
      public static final String LABEL_PREVIOUS = "&lt;";
      public static final String LABEL_NEXT = "&gt;";
      public static final String LABEL_LAST = "&gt;|";
      private static final long serialVersionUID = -2795417742672443863L;
  
      // Variables declarations
      /** page index parameter name */
      protected String _strPageIndexParameterName;
  
      /** items per page */
      protected int _nItemPerPage;
  
      /** base url */
      protected String _strBaseUrl;
  
      /** the actual list */
      protected List<E> _list;
  
      /** the current page */
      protected int _nPageCurrent;
  
      /** items per page parameter name */
      protected String _strItemsPerPageParameterName;
  
      /** element count */
      protected int _nItemsCount;
  
      /**
       * {@inheritDoc}
       */
      @Override
      public int getPageCurrent( )
      {
          return _nPageCurrent;
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public String getFirstPageLink( )
      {
          UrlIteml/UrlItem.html#UrlItem">UrlItem url = new UrlItem( _strBaseUrl );
         url.addParameter( _strPageIndexParameterName, "" + 1 );
 
         return url.getUrl( );
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String getPreviousPageLink( )
     {
         int nPreviousIndex = _nPageCurrent - 1;
         UrlIteml/UrlItem.html#UrlItem">UrlItem url = new UrlItem( _strBaseUrl );
         url.addParameter( _strPageIndexParameterName, "" + nPreviousIndex );
 
         return url.getUrl( );
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String getLastPageLink( )
     {
         UrlIteml/UrlItem.html#UrlItem">UrlItem url = new UrlItem( _strBaseUrl );
         url.addParameter( _strPageIndexParameterName, "" + getPagesCount( ) );
 
         return url.getUrl( );
     }
 
     /**
      *
      * {@inheritDoc}
      */
     @Override
     public int getItemsPerPage( )
     {
         return _nItemPerPage;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String getNextPageLink( )
     {
         int nNextIndex = _nPageCurrent + 1;
         UrlIteml/UrlItem.html#UrlItem">UrlItem url = new UrlItem( _strBaseUrl );
         url.addParameter( _strPageIndexParameterName, "" + nNextIndex );
 
         return url.getUrl( );
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public List<PaginatorPage> getPagesLinks( )
     {
         List<PaginatorPage> list = new ArrayList<>( );
 
         // Number of link pages in total
         int nNbLinkPages = getPagesCount( );
 
         // Max number of link pages displayed
         int nNbLinkPagesToDisplay = 10;
 
         // Number of previous link pages to display
         int nOffsetPrev = nNbLinkPagesToDisplay / 2;
 
         // Number of next link pages to display
         int nOffsetNext = nNbLinkPagesToDisplay / 2;
 
         // Set the offsets
         if ( _nPageCurrent <= ( nNbLinkPagesToDisplay - nOffsetPrev ) )
         {
             // If the current page is within the first 5 pages
             nOffsetPrev = _nPageCurrent - 1;
             nOffsetNext = nNbLinkPagesToDisplay - nOffsetPrev;
         }
         else
             if ( ( _nPageCurrent + nOffsetNext ) > nNbLinkPages )
             {
                 // If the current page is within the last 5 pages
                 nOffsetNext = nNbLinkPages - _nPageCurrent;
                 nOffsetPrev = nNbLinkPagesToDisplay - nOffsetNext;
             }
 
         // Index of the last number of the link page to display
         int nMax = nNbLinkPages;
 
         // Index of the first number of the link page to display
         int nMin = 1;
 
         int nTmpMin = _nPageCurrent - nOffsetPrev;
         int nTmpMax = _nPageCurrent + nOffsetNext;
 
         if ( nTmpMax < nMax )
         {
             nMax = nTmpMax;
         }
 
         if ( nTmpMin > 0 )
         {
             nMin = nTmpMin;
         }
 
         for ( int i = nMin; i <= nMax; i++ )
         {
             PaginatorPagenatorPage.html#PaginatorPage">PaginatorPage page = new PaginatorPage( );
             String strIndex = "" + i;
             UrlIteml/UrlItem.html#UrlItem">UrlItem url = new UrlItem( _strBaseUrl );
             url.addParameter( _strPageIndexParameterName, strIndex );
             page.setUrl( url.getUrl( ) );
             page.setName( strIndex );
             page.setIndex( i );
             list.add( page );
         }
 
         return list;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String getLabelFirst( )
     {
         return LABEL_FIRST;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String getLabelPrevious( )
     {
         return LABEL_PREVIOUS;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String getLabelNext( )
     {
         return LABEL_NEXT;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String getLabelLast( )
     {
         return LABEL_LAST;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String getLabelItemCount( )
     {
         return "";
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String getLabelItemCountPerPage( )
     {
         return "";
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String getItemsPerPageParameterName( )
     {
         return _strItemsPerPageParameterName;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void setItemsPerPageParameterName( String strItemsPerPageParameterName )
     {
         _strItemsPerPageParameterName = strItemsPerPageParameterName;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public int getPagesCount( )
     {
         return ( ( _nItemsCount - 1 ) / _nItemPerPage ) + 1;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public int getRangeMin( )
     {
         return ( !_list.isEmpty( ) ) ? ( ( _nItemPerPage * ( _nPageCurrent - 1 ) ) + 1 ) : 0;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public int getRangeMax( )
     {
         return ( _nItemsCount < ( ( _nItemPerPage * _nPageCurrent ) - 1 ) ) ? _nItemsCount : ( _nItemPerPage * _nPageCurrent );
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public int getItemsCount( )
     {
         return _nItemsCount;
     }
 
     /**
      * Gets the number of items per page from a request parameter
      * 
      * @param request
      *            The HTTP request
      * @param strParameter
      *            The request parameter name
      * @param nCurrent
      *            The current number of items
      * @param nDefault
      *            The default number of items
      * @return The new number of items
      */
     public static int getItemsPerPage( HttpServletRequest request, String strParameter, int nCurrent, int nDefault )
     {
         int nItemsPerPage;
         String strItemsPerPage = request.getParameter( strParameter );
 
         if ( strItemsPerPage != null )
         {
             nItemsPerPage = Integer.parseInt( strItemsPerPage );
         }
         else
         {
             if ( nCurrent != 0 )
             {
                 nItemsPerPage = nCurrent;
             }
             else
             {
                 nItemsPerPage = nDefault;
             }
         }
 
         return nItemsPerPage;
     }
 
     /**
      * Gets the new page index from a request parameter
      * 
      * @param request
      *            The HTTP request
      * @param strParameter
      *            The request parameter name
      * @param strCurrentPageIndex
      *            The current page index
      * @return The new page index
      */
     public static String getPageIndex( HttpServletRequest request, String strParameter, String strCurrentPageIndex )
     {
         String strPageIndex = request.getParameter( strParameter );
         strPageIndex = ( strPageIndex != null ) ? strPageIndex : strCurrentPageIndex;
 
         return strPageIndex;
     }
 }