/**
    * Copyright 2005-2014 The Kuali Foundation
    *
    * Licensed under the Educational Community License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    * http://www.opensource.org/licenses/ecl2.php
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.kuali.rice.krad.uif.widget;
  
  import org.kuali.rice.krad.uif.component.Component;
  import org.kuali.rice.krad.uif.util.LifecycleElement;
  
  /**
   * The Pager widget is used to display a list of links horizontally in a page selection user interface.  The user can
   * select a page to jump to, go to prev/next page, or go to the first or last page.  This widget needs to know
   * the numberOfPages total, and the currentPage the user is on currently, so this widget must be fed this information
   * from the code.
   *
   * @author Kuali Rice Team (rice.collab@kuali.org)
   * @see org.kuali.rice.krad.uif.layout.StackedLayoutManager
   */
  public class Pager extends WidgetBase {
      private String linkScript;
      private int maxNumberedLinksShown;
      private int numberOfPages;
      private int currentPage;
      private boolean renderPrevNext;
      private boolean renderFirstLast;
  
      protected int pagesStart;
      protected int pagesEnd;
  
      public Pager() {
          super();
      }
  
      /**
       * performFinalize calculates the pagesStart and pagesEnd properties (using numberOfPages, currentPage, and
       * maxNumberedLinksShown - these must be set) which determines pages shown by the widget
       *
       * @param model the current model
       * @param parent parent container
       */
      @Override
      public void performFinalize(Object model, LifecycleElement parent) {
          super.performFinalize(model, parent);
  
          // if no pages or 1 page, do not render
          if (numberOfPages == 0 || numberOfPages == 1) {
              this.setRender(false);
          }
  
          if (maxNumberedLinksShown >= numberOfPages) {
              // Show all pages if possible to do so
              pagesStart = 1;
              pagesEnd = numberOfPages;
          } else {
              // Determine how many pages max shown before an after the current page
              int beforeAfterShown = (int) Math.floor((double) maxNumberedLinksShown / 2.0);
              pagesStart = currentPage - beforeAfterShown;
              pagesEnd = currentPage + beforeAfterShown;
  
              // If maxNumberedLinksShown is even and cannot have an equal amount of pages showing before
              // and after the current page, so trim one off the end
              if (pagesEnd - pagesStart == maxNumberedLinksShown) {
                  pagesEnd = pagesEnd - 1;
              }
  
              // The pagesEnd is within range of numberOfPages total, therefore show the last pages
              if (pagesEnd > numberOfPages) {
                  pagesEnd = numberOfPages;
                  pagesStart = numberOfPages - maxNumberedLinksShown + 1;
              }
  
              // The pageStart is within range, therefore show the first pages
              if (pagesStart < 1) {
                  pagesStart = 1;
                  if (maxNumberedLinksShown < numberOfPages) {
                      pagesEnd = maxNumberedLinksShown;
                  }
              }
          }
  
          this.linkScript = "e.preventDefault();" + this.linkScript;
      }
  
      /**
       * The script to execute when a link is clicked (should probably use the "this" var in most cases, to determine
       * page number selected - see retrieveStackedPage(linkElement, collectionId) js function)
       *
       * @return the script to execute when a link is clicked
      */
     public String getLinkScript() {
         return linkScript;
     }
 
     /**
      * Set the link js script
      *
      * @param linkScript the link js script
      */
     public void setLinkScript(String linkScript) {
         this.linkScript = linkScript;
     }
 
     /**
      * The maximum number of NUMBERED links shown at once for pages, if number of pages that exist exceed this value,
      * the pager omits some pages before and/or after the current page (which are revealed during while
      * navigating using a carousel effect)
      *
      * @return the maximum number of NUMBERED links to show
      */
     public int getMaxNumberedLinksShown() {
         return maxNumberedLinksShown;
     }
 
     /**
      * Set the maximum number of NUMBERED links shown
      *
      * @param maxNumberedLinksShown
      */
     public void setMaxNumberedLinksShown(int maxNumberedLinksShown) {
         this.maxNumberedLinksShown = maxNumberedLinksShown;
     }
 
     /**
      * Number of pages TOTAL that make up the component being paged (this must be set by the framework based on some
      * list size)
      *
      * @return the number of pages used in this pager
      */
     public int getNumberOfPages() {
         return numberOfPages;
     }
 
     /**
      * Set the TOTAL number of pages
      *
      * @param numberOfPages
      */
     public void setNumberOfPages(int numberOfPages) {
         this.numberOfPages = numberOfPages;
     }
 
     /**
      * The current page being shown by this pager widget (this must be set when the page is changed)
      *
      * @return the current page being shown
      */
     public int getCurrentPage() {
         return currentPage;
     }
 
     /**
      * Set the current page
      *
      * @param currentPage
      */
     public void setCurrentPage(int currentPage) {
         this.currentPage = currentPage;
     }
 
     /**
      * Returns true if this pager widget is rendering the "First" and "Last" links
      *
      * @return true if rendering "First" and "Last" links
      */
     public boolean isRenderFirstLast() {
         return renderFirstLast;
     }
 
     /**
      * Set renderFirstLast
      *
      * @param renderFirstLast
      */
     public void setRenderFirstLast(boolean renderFirstLast) {
         this.renderFirstLast = renderFirstLast;
     }
 
     /**
      * Returns true if this pager widget is rendering the "Prev" and "Next" links
      *
      * @return true if rendering "First" and "Last" links
      */
     public boolean isRenderPrevNext() {
         return renderPrevNext;
     }
 
     /**
      * Set renderPrevNext
      *
      * @param renderPrevNext
      */
     public void setRenderPrevNext(boolean renderPrevNext) {
         this.renderPrevNext = renderPrevNext;
     }
 
     /**
      * The first page number to render; this is set by the framework
      *
      * @return pages start
      */
     public int getPagesStart() {
         return pagesStart;
     }
 
     /**
      * The last page number to render; this is set by the framework
      *
      * @return last page number to render
      */
     public int getPagesEnd() {
         return pagesEnd;
     }
 }