/**
    * This file Copyright (c) 2012-2012 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.templating.jsp.taglib;
  
  import info.magnolia.cms.core.Content;
  import info.magnolia.cms.core.Content.ContentFilter;
  import info.magnolia.cms.core.ItemType;
  import info.magnolia.cms.core.NodeData;
  import info.magnolia.cms.i18n.I18nContentSupportFactory;
  import info.magnolia.context.MgnlContext;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.List;
  
  import javax.jcr.RepositoryException;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.jsp.JspException;
  import javax.servlet.jsp.JspWriter;
  import javax.servlet.jsp.tagext.TagSupport;
  
  import org.apache.commons.lang.StringEscapeUtils;
  import org.apache.commons.lang.StringUtils;
  import org.apache.commons.lang.exception.NestableRuntimeException;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.tldgen.annotations.BodyContent;
  import org.tldgen.annotations.Tag;
  
  /**
   * Draws a simple, css based, navigation menu. The menu layout can then be customized using css, and the default menu
   * should be enough for most uses. Two following page properties will also be used in the menu:
   * <ul>
   * <li><code>navTitle</code>: a title to use for the navigation menu, if different from the real page title</li>
   * <li><code>accessKey</code>: an optional access key which will be added to the link</li>
   * <li><code>wrappingElement</code>: an optional html element (div, span, p, etc) to go within the &lt;a&gt; tag wrapping the anchor text
   * </ul>
   *
   * @jsp.tag name="simpleNavigation" body-content="empty"
   * @jsp.tag-example
   * <pre>
   * &lt;cmsu:simpleNavigation startLevel="3" style="mystyle"/&gt;
   *
   * Will output the following:
   *
   * &lt;ul class="level3 mystyle"&gt;
   *     &lt;li&gt;&lt;a href="..."&gt;page 1 name &lt;/a&gt;&lt;/li&gt;
   *     &lt;li&gt;&lt;a href="..."&gt;page 2 name &lt;/a&gt;&lt;/li&gt;
   *     &lt;li class="trail"&gt;&lt;a href="..."&gt;page 3 name &lt;/a&gt;
   *         &lt;ul class="level3"&gt;
   *             &lt;li&gt;&lt;a href="..."&gt;subpage 1 name &lt;/a&gt;&lt;/li&gt;
   *             &lt;li&gt;&lt;a href="..."&gt;subpage 2 name &lt;/a&gt;&lt;/li&gt;
   *             &lt;li&gt;&lt;strong&gt;&lt;a href="..."&gt;selected page name &lt;/a&gt;&lt;/strong&gt;&lt;/li&gt;
   *         &lt;/ul&gt;
   *     &lt;/li&gt;
   *     &lt;li&gt;&lt;a href="..."&gt;page 4 name &lt;/a&gt;&lt;/li&gt;
   * &lt;/ul&gt;
   *</pre>
   *
   * @author Fabrizio Giustina
   * @version $Revision$ ($Author$)
   */
  @Tag(name="simpleNavigation", bodyContent=BodyContent.EMPTY)
  
  public class SimpleNavigationTag extends TagSupport {
 
     /**
      * Css class added to active page.
      */
     private static final String CSS_LI_ACTIVE = "active";
 
     /**
      * Css class added to ancestor of the active page.
      */
     private static final String CSS_LI_TRAIL = "trail";
 
     /**
      * Css class added to leaf pages.
      */
     private static final String CSS_LI_LEAF = "leaf"; 
 
     /**
      * Css class added to open trees.
      */
     private static final String CSS_LI_CLOSED = "closed"; 
 
     /**
      * Css class added to closed trees.
      */
     private static final String CSS_LI_OPEN = "open"; 
 
     /**
      * Css class added to first li in ul.
      */
     private static final String CSS_LI_FIRST = "first"; 
 
     /**
      * Css class added to last li in ul.
      */
     private static final String CSS_LI_LAST = "last"; 
 
     /**
      * Page property: navigation title.
      */
     private static final String NODEDATA_NAVIGATIONTITLE = "navTitle"; 
 
     /**
      * Page property: access key.
      */
     public static final String NODEDATA_ACCESSKEY = "accessKey"; 
 
     /**
      * Default name for "open menu" nodeData.
      */
     public static final String DEFAULT_OPENMENU_NODEDATA = "openMenu"; 
 
     /**
      * Default name for "hide in nav" nodeData.
      */
     public static final String DEFAULT_HIDEINNAV_NODEDATA = "hideInNav"; 
 
     /**
      * Default name for "wrapperElement" nodeData.
      */
     public static final String DEFAULT_WRAPPERELEMENT_NODEDATA = ""; 
 
     /**
      * Expand all expand all the nodes.
      */
     public static final String EXPAND_ALL = "all";
 
     /**
      * Expand all expand only page that should be displayed in navigation.
      */
     public static final String EXPAND_SHOW = "show";
 
     /**
      * Do not use expand functions.
      */
     public static final String EXPAND_NONE = "none";
 
     /**
      * Stable serialVersionUID.
      */
     private static final long serialVersionUID = 224L;
 
     /**
      * Logger.
      */
     private static Logger log = LoggerFactory.getLogger(SimpleNavigationTag.class);
 
     /**
      * Start level.
      */
     private int startLevel;
 
     /**
      * End level.
      */
     private int endLevel;
 
     /**
      * Name for the "hide in nav" nodeData.
      */
     private String hideInNav;
 
     /**
      * Name for the "open menu" nodeData.
      */
     private String openMenu;
 
     /**
      * Style to apply to the menu.
      */
     private String style;
 
     /**
      * html element to wrap the anchortext. (i.e. &lt;a&gt;&lt;wrapper&gt;...&lt;/wrapper&gt;&lt;/a&gt;)
      */
     public String wrapperElement;
 
     /**
      * Expand all the nodes. (sitemap mode)
      */
     private String expandAll = EXPAND_NONE;
 
     private boolean relativeLevels = false;
 
     /**
      * Name for a page property which will be written to the css class attribute.
      */
     private String classProperty;
 
     /**
      * Name for the "nofollow" hodeData (for link that must be ignored by search engines).
      */
     private String nofollow;
 
 
     /**
      * Content Filter to use to evaluate if a page should be drawn.
      */
     private ContentFilter filter;
 
     private String contentFilter = "";
 
     /**
      * Flag to set if the first and last li in each ul should be marked with a special css class.
      */
     private boolean markFirstAndLastElement = false;
 
     /**
      * The start level for navigation, defaults to 0.
      * @jsp.attribute required="false" rtexprvalue="true" type="int"
      */
     public void setStartLevel(int startLevel) {
         this.startLevel = startLevel;
     }
 
     /**
      * The end level for navigation, defaults to 0.
      * @jsp.attribute required="false" rtexprvalue="true" type="int"
      */
     public void setEndLevel(int endLevel) {
         this.endLevel = endLevel;
     }
 
     /**
      * The css class to be applied to the first ul. Default is empty.
      * @jsp.attribute required="false" rtexprvalue="true"
      */
     public void setStyle(String style) {
         this.style = style;
     }
 
     /**
      * Name for the "hide in nav" nodeData. If a page contains a boolean property with this name and
      * it is set to true, the page is not shown in navigation. Defaults to "hideInNav".
      * @jsp.attribute required="false" rtexprvalue="true"
      */
     public void setHideInNav(String hideInNav) {
         this.hideInNav = hideInNav;
     }
 
     /**
      * Name for the "open menu" nodeData. If a page contains a boolean property with this name and
      * it is set to true, subpages are always shown also if the page is not selected.
      * Defaults to "openMenu".
      * @jsp.attribute required="false" rtexprvalue="true"
      */
     public void setOpenMenu(String openMenu) {
         this.openMenu = openMenu;
     }
 
     /**
      * Name for the "nofollow" nodeData. If a page contains a boolean property with this name
      * and it is set to true, rel="nofollow" will be added to the generated link
      * (for links the should be ignored by search engines).
      * @jsp.attribute required="false" rtexprvalue="true"
      */
     public void setNofollow(String nofollow) {
         this.nofollow = nofollow;
     }
 
     /**
      * A variable in the pageContext that contains a content filter, determining if a given page should be drawn or not.
      * @jsp.attribute required="false" rtexprvalue="true"
      */
     public void setContentFilter(String contentFilter) {
         this.contentFilter = contentFilter;
     }
 
     /**
      * Sitemap mode. Can be assigned the "show" value. Only showable pages will be displayed. Any other value will
      * result in displaying all pages.
      * @jsp.attribute required="false" rtexprvalue="true"
      */
     public void setExpandAll(String expandAll) {
         if (expandAll.equalsIgnoreCase(EXPAND_SHOW)) {
             this.expandAll = expandAll;
         }
         else {
             this.expandAll = EXPAND_ALL;
         }
     }
 
     /**
      * If set to true, the startLevel and endLevel values are treated relatively to the current active page.
      * The default value is false.
      * @jsp.attribute required="false" rtexprvalue="true" type="boolean"
      */
     public void setRelativeLevels(boolean relativeLevels) {
         this.relativeLevels = relativeLevels;
     }
 
     /**
      * Name for a page property that will hold a css class name which will be added to the html class attribute.
      * @jsp.attribute required="false" rtexprvalue="true"
      */
     public void setClassProperty(String classProperty) {
         this.classProperty = classProperty;
     }
 
     /**
      * When specified, all links will have the anchortext wrapped in the supplied element. (such as "span")
      * @param wrapperElement name of an html element that will be included in the anchor, wrapping the anchortext
      * @jsp.attribute required="false" rtexprvalue="true"
      */
     public void setWrapperElement(String wrapperElement) {
         this.wrapperElement = wrapperElement;
     }
 
     /**
      * If set to true, a "first" or "last" css class will be added to the list of css classes of the
      * first and the last li in each ul.
      * @jsp.attribute required="false" rtexprvalue="true" type="boolean"
      */
     public void setMarkFirstAndLastElement(boolean flag) {
         markFirstAndLastElement = flag;
     }
 
     @Override
     public int doEndTag() throws JspException {
         Content activePage = getCurrentActivePage();
         try {
             while (!ItemType.CONTENT.getSystemName().equals(activePage.getNodeTypeName()) && activePage.getParent() != null) {
                 activePage = activePage.getParent();
             }
         } catch (RepositoryException e) {
             log.error("Failed to obtain parent page for " + getCurrentActivePage().getHandle(), e);
             activePage = getCurrentActivePage();
         }
         JspWriter out = this.pageContext.getOut();
 
         if (StringUtils.isNotEmpty(this.contentFilter)) {
             try {
                 filter = (ContentFilter) this.pageContext.getAttribute(this.contentFilter);
             }
             catch(ClassCastException e) {
                 log.error("contentFilter assigned was not a content filter", e);
             }
         } else {
             filter = null;
         }
 
         if (startLevel > endLevel) {
             endLevel = 0;
         }
 
         try {
             final int activePageLevel = activePage.getLevel();
             // if we are to treat the start and end level as relative
             // to the active page, we adjust them here...
             if (relativeLevels) {
                 this.startLevel += activePageLevel;
                 this.endLevel += activePageLevel;
             }
             if (this.startLevel <= activePageLevel) {
                 Content startContent = activePage.getAncestor(this.startLevel);
                 drawChildren(startContent, activePage, out);
             }
 
         }
         catch (RepositoryException e) {
             log.error("RepositoryException caught while drawing navigation: " + e.getMessage(), e); 
             return EVAL_PAGE;
         }
         catch (IOException e) {
             // should never happen
             throw new NestableRuntimeException(e);
         }
 
         return EVAL_PAGE;
     }
 
     @Override
     public void release() {
         this.startLevel = 0;
         this.endLevel = 0;
         this.hideInNav = null;
         this.openMenu = null;
         this.style = null;
         this.classProperty = null;
         this.expandAll = EXPAND_NONE;
         this.relativeLevels = false;
         this.wrapperElement = "";
         this.contentFilter = "";
         this.filter = null;
         this.nofollow = null;
         this.markFirstAndLastElement = false;
         super.release();
     }
 
     /**
      * Draws page children as an unordered list.
      * @param page current page
      * @param activePage active page
      * @param out jsp writer
      * @throws IOException jspwriter exception
      * @throws RepositoryException any exception thrown during repository reading
      */
     private void drawChildren(Content page, Content activePage, JspWriter out) throws IOException, RepositoryException {
 
         Collection<Content> children = new ArrayList<Content>(page.getChildren(ItemType.CONTENT));
 
         if (children.size() == 0) {
             return;
         }
 
         out.print("<ul class=\"level");
         out.print(page.getLevel());
         if (style != null && page.getLevel() == startLevel) {
             out.print(" ");
             out.print(style);
         }
         out.print("\">");
 
         Iterator<Content> iter = children.iterator();
         // loop through all children and discard those we don't want to display
         while(iter.hasNext()) {
             final Content child = iter.next();
 
             if (expandAll.equalsIgnoreCase(EXPAND_NONE) || expandAll.equalsIgnoreCase(EXPAND_SHOW)) {
                 if (child
                     .getNodeData(StringUtils.defaultString(this.hideInNav, DEFAULT_HIDEINNAV_NODEDATA)).getBoolean()) {
                     iter.remove();
                     continue;
                 }
                 // use a filter
                 if (filter != null) {
                     if (!filter.accept(child)) {
                         iter.remove();
                         continue;
                     }
                 }
             } else {
                 if (child.getNodeData(StringUtils.defaultString(this.hideInNav, DEFAULT_HIDEINNAV_NODEDATA)).getBoolean()) {
                     iter.remove();
                     continue;
                 }
             }
         }
 
         boolean isFirst = true;
         Iterator<Content> visibleIt = children.iterator();
         while (visibleIt.hasNext()) {
             Content child = visibleIt.next();
             List<String> cssClasses = new ArrayList<String>(4);
 
             NodeData nodeData = I18nContentSupportFactory.getI18nSupport().getNodeData(child, NODEDATA_NAVIGATIONTITLE);
             String title = nodeData.getString(StringUtils.EMPTY);
 
             // if nav title is not set, the main title is taken
             if (StringUtils.isEmpty(title)) {
                 title = child.getTitle();
             }
 
             // if main title is not set, the name of the page is taken
             if (StringUtils.isEmpty(title)) {
                 title = child.getName();
             }
 
             boolean showChildren = false;
             boolean self = false;
 
             if (!expandAll.equalsIgnoreCase(EXPAND_NONE)) {
                 showChildren = true;
             }
 
             if (activePage.getHandle().equals(child.getHandle())) {
                 // self
                 showChildren = true;
                 self = true;
                 cssClasses.add(CSS_LI_ACTIVE);
             }
             else if (!showChildren) {
                 showChildren = (child.getLevel() <= activePage.getAncestors().size() && activePage.getAncestor(
                     child.getLevel()).getHandle().equals(child.getHandle()));
             }
 
             if (!showChildren) {
                 showChildren = child
                     .getNodeData(StringUtils.defaultString(this.openMenu, DEFAULT_OPENMENU_NODEDATA))
                     .getBoolean();
             }
 
             if (endLevel > 0) {
                 showChildren &= child.getLevel() < endLevel;
             }
 
             cssClasses.add(hasVisibleChildren(child) ? (showChildren ? CSS_LI_OPEN : CSS_LI_CLOSED) : CSS_LI_LEAF);
 
             if (child.getLevel() < activePage.getLevel()
                 && activePage.getAncestor(child.getLevel()).getHandle().equals(child.getHandle())) {
                 cssClasses.add(CSS_LI_TRAIL);
             }
 
             if (StringUtils.isNotEmpty(classProperty) && child.hasNodeData(classProperty)) {
                 cssClasses.add(child.getNodeData(classProperty).getString(StringUtils.EMPTY));
             }
 
             if (markFirstAndLastElement && isFirst) {
                 cssClasses.add(CSS_LI_FIRST);
                 isFirst = false;
             }
 
             if (markFirstAndLastElement && !visibleIt.hasNext()) {
                 cssClasses.add(CSS_LI_LAST);
             }
 
             StringBuffer css = new StringBuffer(cssClasses.size() * 10);
             Iterator<String> iterator = cssClasses.iterator();
             while (iterator.hasNext()) {
                 css.append(iterator.next());
                 if (iterator.hasNext()) {
                     css.append(" "); 
                 }
             }
 
             out.print("<li class=\""); 
             out.print(css.toString());
             out.print("\">"); 
 
             if (self) {
                 out.println("<strong>"); 
             }
 
             String accesskey = child.getNodeData(NODEDATA_ACCESSKEY).getString(StringUtils.EMPTY);
 
             out.print("<a href=\""); 
             out.print(((HttpServletRequest) this.pageContext.getRequest()).getContextPath());
             out.print(I18nContentSupportFactory.getI18nSupport().toI18NURI(child.getHandle()));
             out.print(".html\""); 
 
             if (StringUtils.isNotEmpty(accesskey)) {
                 out.print(" accesskey=\""); 
                 out.print(accesskey);
                 out.print("\""); 
             }
 
             if (nofollow != null && child.getNodeData(this.nofollow).getBoolean())
             {
                 out.print(" rel=\"nofollow\""); 
             }
 
             out.print(">"); 
 
             if (StringUtils.isNotEmpty(this.wrapperElement)) {
                 out.print("<" + this.wrapperElement + ">"); 
             }
 
             out.print(StringEscapeUtils.escapeHtml(title));
 
             if (StringUtils.isNotEmpty(this.wrapperElement)) {
                 out.print("</" + this.wrapperElement + ">"); 
             }
 
             out.print(" </a>"); 
 
             if (self) {
                 out.println("</strong>"); 
             }
 
             if (showChildren) {
                 drawChildren(child, activePage, out);
             }
             out.print("</li>"); 
         }
 
         out.print("</ul>"); 
     }
 
     /**
      * Checks if the page has a visible children. Pages with the <code>hide in nav</code> attribute set to
      * <code>true</code> are ignored.
      * @param page root page
      * @return <code>true</code> if the given page has at least one visible child.
      */
     private boolean hasVisibleChildren(Content page) {
         Collection<Content> children = page.getChildren();
         if (children.size() > 0 && expandAll.equalsIgnoreCase(EXPAND_ALL)) {
             return true;
         }
         for (Content ch : children) {
             if (!ch.getNodeData(StringUtils.defaultString(this.hideInNav, DEFAULT_HIDEINNAV_NODEDATA)).getBoolean()) {
                 return true;
             }
         }
         return false;
     }
     
     protected Content getCurrentActivePage(){
         Content currentActpage = MgnlContext.getAggregationState().getCurrentContent();
         if (currentActpage == null) {
             currentActpage = MgnlContext.getAggregationState().getMainContent();
         }
         return currentActpage;
     }
 
 }