/*******************************************************************************

  * Copyright (c) 2005 Gabriel Handford.

  * All rights reserved.

  *

  * Contributors - Gabriel Handford

  ********************************************************************************/

 package net.sf.tacos.services.impl;

 import java.util.ArrayList;

 import java.util.Arrays;

 import java.util.HashMap;

 import java.util.Iterator;

 import java.util.LinkedList;

 import java.util.List;

 import java.util.Map;

 import net.sf.tacos.services.CategoryInfo;

 import net.sf.tacos.services.PageInfo;

 import net.sf.tacos.services.SiteMap;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.apache.hivemind.Resource;

 import org.dom4j.Document;

 import org.dom4j.DocumentException;

 import org.dom4j.Element;

 import org.dom4j.Node;

 import org.dom4j.io.SAXReader;

 /**

  * This class reads the sitemap configuration, and provides access to

  * basic relationship information, such as page categories, bread crumbs, and

  * other information, that the application may need to ease navigation.

  *

  * @author Gabriel Handford

  */

 public class SiteMapImpl implements SiteMap {

     private static final Log log = LogFactory.getLog(SiteMapImpl.class);

     private Resource resource;

     private Document document;

     private List cachedCategoryList = null;

     private Map cachedPageMap = new HashMap();

     private Map cachedCategoryInfo = new HashMap();

     private boolean compact;

     /**

      * Empty constructor.

      */

     public SiteMapImpl() { }

     /**

      * Set the sitemap resource (xml).

      * @param resource The resource (xml) file

      */

     public void setResource(Resource resource) {

         this.resource = resource;        

     }

     /**

      * Initialize site map from a url (xml document).

      * @throws DocumentException on error

      * @throws IllegalStateException If no resource has been set.

      */

     public void initialize() throws DocumentException {

         if (resource == null)

             throw new IllegalStateException(

                     "No resource set, call setResource(..) before initialize()");

         if (resource.getResourceURL() == null)

             throw new IllegalStateException(

                     "No valid resource URL could be resolved:" + resource);

         log.debug("Sitemap resource: " + resource.getResourceURL());

         SAXReader reader = new SAXReader();

         document = reader.read(resource.getResourceURL());

         Element main = (Element)document.selectSingleNode("/sitemap");

         String val = main.attributeValue("compact");

         if (val != null && !val.trim().equals("")) 

             compact = Boolean.valueOf(val).booleanValue();

     }

     /**

      * Check if page name is contained in the page element tree.

      * @param parentName The page to look for.

      * @param pageName The page to start at (moves bottom-up).

      * @return True if the parent contains the page in its tree.

      */

     public boolean contains(String parentName, String pageName) {

         PageInfo pageInfo = getPageInfo(pageName);

         return containsImpl(parentName, pageInfo);

     }

     /**

      * Check if page name is contained in the page element tree.

      * @param parentName The page to look for.

      * @param pageInfo The page to start at (moves bottom-up).

      * @return True if the parent contains the page in its tree.

      */

     private boolean containsImpl(String parentName, PageInfo pageInfo) {

         if (pageInfo == null) return false;

         PageInfo parent = pageInfo.getParent();

         if (parent == null) return false;

         else if (parent.getName().equals(parentName)) return true;

         else return containsImpl(parentName, parent);

     }

     /**

      * Get page information.

      * @param name The page name

      * @return The page info

      */

     public PageInfo getPageInfo(String name) {

         return getPageInfoCacheImpl(name, null);

     }

     /**

      * Get page information (from cache).

      * @param name The page name.

      * @param source The page name source (for cycle detetion, first time is null).

      * @return The page.

      */

     private PageInfo getPageInfoCacheImpl(String name, String source) {

         PageInfo pi = (PageInfo)cachedPageMap.get(name);

         if (pi == null) {

             pi = getPageInfoImpl(name, source);

             if (pi != null) cachedPageMap.put(name, pi);

         } else {

             //log.debug("Returning cached page info: " + name);

         }

         return pi;

     }

     /**

      * Get page information.

      * @param name The page name

      * @param source Original page name (for cycle detection)

      * @return The page info

      */

     private PageInfo getPageInfoImpl(String name, String source) {

         if (document == null) throw new IllegalStateException("No document set, call setResource and initialize.");

         // Cycle check

         if (source != null && name.equals(source))

             throw new IllegalStateException("Found a cycle, " + name + "->" + source);

         else if (source == null)

             source = name;

         Element node = findPageNode(name);

         if (node != null) {

             PageInfo page = parsePageNode(node);

             Node pageCategoryNode = document.selectSingleNode("/sitemap/category//page[@name='" + name + "']");

             if (pageCategoryNode != null) {

                 parseNodeTree(page, pageCategoryNode);

                 //Because it will have been re-parsed

                 return (PageInfo)cachedPageMap.get(page.getName());

             }

             return page;

         }

         return null;

     }

     /**

      * Finds the specified page node in the sitemap, first trying to find

      * it by name and then path.

      * @param page

      * @return The page, or null if not found.

      */

     protected Element findPageNode(String page)

     {

         Element element = (Element)document.selectSingleNode("/sitemap/page[@name='" + page + "']");

         if (element == null && compact)

         {

             element = (Element)document.selectSingleNode("/sitemap/category//page[@name='" + page + "']");

         }

         return element;       

     }

     /**

      * Parses a particular page node, doesn't parse

      * children or parent of {@link PageInfo}.

      * 

      * @param node Node to parse.

      * @return

      */

     protected PageInfo parsePageNode(Element node)

     {

         if (node == null || !node.getName().equals("page"))

             throw new IllegalArgumentException("Node was null or not a page node.");

         String name = node.attributeValue("name");

         String desc = node.attributeValue("desc");

         String perm = node.attributeValue("permission");

         String listItem = node.attributeValue("navigable");

         //Whether or not to list this page if a child.

         boolean list = true;

         if (listItem != null && !listItem.trim().equals("")) 

             list = Boolean.valueOf(listItem).booleanValue();

         PageInfo page = new PageInfoImpl(name, desc, perm, new ArrayList(), list);

         return page;

     }

     /**

      * Iterates through the category tree represented 

      * by this page node and parses all children and parents.

      * 

      * @param page The page that caused the tree parse

      * @param pageNode

      */

     protected void parseNodeTree(PageInfo page, Node pageNode)

     {

         //First find top-level parent

         Node parent = pageNode;

         while (parent.getParent() != null 

                 && parent.getParent().getName().equals("page")) {

             parent = parent.getParent();

         }

         log.debug("Parsing tree for page <" + page.getName() + ">");

         //We can now parse all children of parent

         parsePageNodes(parent, page);

     }

     /**

      * Parses all children of specified node and adds them

      * to the page cache.

      * 

      * @param parent

      * @param source Page that caused the original parse.

      * @return The parent node that was parsed.

      */

     protected PageInfo parsePageNodes(Node parent, PageInfo source)

     {

         PageInfo parentInfo = parsePageNode(findPageNode(((Element)parent).attributeValue("name")));

         cachedPageMap.put(parentInfo.getName(), parentInfo);

         log.debug("Parent page name <" + parent.valueOf("@name") + ">");

         Iterator it = parent.selectNodes("*").iterator();

         while (it.hasNext()) {

             Node child = (Node)it.next();

             PageInfo childInfo = parsePageNodes(child, source);

             childInfo.setParent(parentInfo);

             parentInfo.addChild(childInfo);

         }

         return parentInfo;

     }

     /**

      * Get category listing.

      * @return The category list

      */

     public synchronized List getCategories() {

         if (document == null) throw new IllegalStateException("No document set, call setResource and initialize.");

         if (cachedCategoryList == null) {

             List nodes = document.selectNodes("/sitemap/category[@name]");

             cachedCategoryList = new ArrayList(nodes.size());

             for(int i = 0, size = nodes.size(); i < size; i++) {

                 String category = ((Node)nodes.get(i)).valueOf("@name");

                 cachedCategoryList.add(category);

             }

         }

         return cachedCategoryList;

     }

     /**

      * Get category info for named category.

      * @param name Category name

      * @return The category info

      * @see SiteMap#getCategoryInfo(java.lang.String)

      */

     public CategoryInfo getCategoryInfo(String name) {

         CategoryInfo ci = (CategoryInfo)cachedCategoryInfo.get(name);

         if (ci != null) {

             return ci;

         }

         if (document == null) throw new IllegalStateException("No document set, call setResource and initialize.");

         String imgName = null;

         String inactiveImgName = null;

         Element catnode = (Element)document.selectSingleNode("/sitemap/category[@name='" + name + "']");

         if (catnode != null) {

             imgName = catnode.attributeValue("image-active");

             inactiveImgName = catnode.attributeValue("image-inactive");

         }

         //Node node = document.selectSingleNode("/sitemap/category[@name='" + name + "']");

         List nodes = document.selectNodes("/sitemap/category[@name='" + name + "']/page");

         if (nodes != null) {

             List pageNames = new ArrayList(nodes.size());

             for(int i = 0; i < nodes.size(); i++) {

                 Node node = (Node)nodes.get(i);

                 String pageName = node.valueOf("@name");

                 pageNames.add(pageName);

             }

             ci = new CategoryInfoImpl(name, pageNames, imgName, inactiveImgName);

             cachedCategoryInfo.put(name, ci);

             return ci;

         }

         ci = new CategoryInfoImpl(name, null);

         cachedCategoryInfo.put(name, ci);

         return ci;

     }

     /**

      * Traverse up the tree to find the super parent.

      * @param pageInfo The page.

      * @return The topmost page.

      */

     private PageInfo getOrigin(PageInfo pageInfo) {

         if (pageInfo != null && pageInfo.getParent() != null) return getOrigin(pageInfo.getParent());

         return pageInfo;

     }

     /**

      * Get the category info for the page name.

      * @param pageName The page name.

      * @return The first category associated with this page.

      */

     public CategoryInfo getCategoryFromPage(String pageName) {

         PageInfo pageInfo = getPageInfo(pageName);

         if (pageInfo != null) {

             PageInfo topMostPage = getOrigin(pageInfo);

             String topPageName = topMostPage.getName();

             Node node = document.selectSingleNode("/sitemap/category/page[@name='" + topPageName + "']");

             if (node != null) {

                 String categoryName = node.getParent().valueOf("@name");

                 return getCategoryInfo(categoryName);

             }

         }

         return null;

     }

     /**

      * Check if page name is in the specified category.

      * @param pageName Page name

      * @param category Category

      * @return True if in the specified category

      */

     public boolean inCategory(String pageName, String category) {                

         CategoryInfo ci = getCategoryFromPage(pageName);

         return (ci != null && ci.getName().equals(category));

     }

     /**

      * Get the default page.

      * @param category Category

      * @return Default page

      */

     public PageInfo getDefaultPage(String category) {

         CategoryInfo ci = getCategoryInfo(category);

         if (ci == null) return null;

         return getPageInfo(ci.getDefaultPage());

     }

     /**

      * Get pages for a specific page names category.

      * @param pageName Page name

      * @return Pages

      */

     public List getCategoryPages(String pageName) {

         CategoryInfo ci = getCategoryFromPage(pageName);

         if (ci == null) return Arrays.asList(new Object[0]);

         return ci.getPageNames();        

     }

     /**

      * Get the default page description.

      * @param category Category

      * @return Category default page description

      */

     public String getDefaultPageDesc(String category) {

         PageInfo pi = getDefaultPage(category);

         if (pi == null) return null;

         return pi.getDesc();

     }

     /**

      * Get bread crumbs.

      * @param pageName The page name.

      * @return The bread crumbs (page name list).

      */

     public List getBreadCrumbs(String pageName) {

         List list = new LinkedList();

         PageInfo pageInfo = getPageInfo(pageName);

         if (pageInfo == null) return Arrays.asList(new Object[0]);

         loadBreadCrumbs(pageInfo, list);

         return list;

     }

     /**

      * Load bread crumbs.

      * @param pageInfo The page.

      * @param breadCrumbs The list.

      */

     private void loadBreadCrumbs(PageInfo pageInfo, List breadCrumbs) {

         PageInfo parent = pageInfo.getParent();

         if (parent == null || parent.getName().equals(""))

             return;

         breadCrumbs.add(0, parent.getName());

         loadBreadCrumbs(parent, breadCrumbs);

     }

     public boolean getCompact()

     {

         return compact;

     }

 }