/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache 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.apache.org/licenses/LICENSE-2.0
   *
   * 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.apache.maven.doxia.site.inheritance;
  
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.maven.doxia.site.Banner;
  import org.apache.maven.doxia.site.Body;
  import org.apache.maven.doxia.site.LinkItem;
  import org.apache.maven.doxia.site.Logo;
  import org.apache.maven.doxia.site.Menu;
  import org.apache.maven.doxia.site.MenuItem;
  import org.apache.maven.doxia.site.SiteModel;
  import org.codehaus.plexus.util.xml.Xpp3Dom;
  
  /**
   * Manage inheritance of the site model.
   *
   * @author <a href="mailto:brett@apache.org">Brett Porter</a>
   * @author <a href="mailto:henning@apache.org">Henning P. Schmiedehausen</a>
   */
  @Singleton
  @Named
  public class DefaultSiteModelInheritanceAssembler implements SiteModelInheritanceAssembler {
      /** {@inheritDoc} */
      public void assembleModelInheritance(
              String name, SiteModel child, SiteModel parent, String childBaseUrl, String parentBaseUrl) {
          if (parent == null || !child.isMergeParent()) {
              return;
          }
  
          child.setCombineSelf(parent.getCombineSelf());
  
          URLRebaser urlContainer = new URLRebaser(parentBaseUrl, childBaseUrl);
  
          if (child.getBannerLeft() == null && parent.getBannerLeft() != null) {
              child.setBannerLeft(parent.getBannerLeft().clone());
              rebaseBannerPaths(child.getBannerLeft(), urlContainer);
          }
  
          if (child.getBannerRight() == null && parent.getBannerRight() != null) {
              child.setBannerRight(parent.getBannerRight().clone());
              rebaseBannerPaths(child.getBannerRight(), urlContainer);
          }
  
          if (child.isDefaultPublishDate() && parent.getPublishDate() != null) {
              child.setPublishDate(parent.getPublishDate().clone());
          }
  
          if (child.isDefaultVersion() && parent.getVersion() != null) {
              child.setVersion(parent.getVersion().clone());
          }
  
          if (child.getEdit() == null && parent.getEdit() != null) {
              child.setEdit(parent.getEdit());
          }
  
          if (child.getSkin() == null && parent.getSkin() != null) {
              child.setSkin(parent.getSkin().clone());
          }
  
          child.setPoweredBy(mergePoweredByLists(child.getPoweredBy(), parent.getPoweredBy(), urlContainer));
  
          if (parent.getLastModified() > child.getLastModified()) {
              child.setLastModified(parent.getLastModified());
          }
  
          assembleBodyInheritance(name, child, parent, urlContainer);
  
          assembleCustomInheritance(child, parent);
      }
  
      /** {@inheritDoc} */
      public void resolvePaths(final SiteModel siteModel, final String baseUrl) {
          if (baseUrl == null) {
              return;
          }
  
          if (siteModel.getBannerLeft() != null) {
             relativizeBannerPaths(siteModel.getBannerLeft(), baseUrl);
         }
 
         if (siteModel.getBannerRight() != null) {
             relativizeBannerPaths(siteModel.getBannerRight(), baseUrl);
         }
 
         for (Logo logo : siteModel.getPoweredBy()) {
             relativizeLogoPaths(logo, baseUrl);
         }
 
         if (siteModel.getBody() != null) {
             for (LinkItem linkItem : siteModel.getBody().getLinks()) {
                 relativizeLinkItemPaths(linkItem, baseUrl);
             }
 
             for (LinkItem linkItem : siteModel.getBody().getBreadcrumbs()) {
                 relativizeLinkItemPaths(linkItem, baseUrl);
             }
 
             for (Menu menu : siteModel.getBody().getMenus()) {
                 relativizeMenuPaths(menu.getItems(), baseUrl);
             }
         }
     }
 
     /**
      * Resolves all relative paths between the elements in a banner. The banner element might contain relative paths
      * to the oldBaseUrl, these are changed to the newBannerUrl.
      *
      * @param banner
      * @param baseUrl
      */
     private void relativizeBannerPaths(final Banner banner, final String baseUrl) {
         // banner has been checked to be not null, both href and src may be empty or null
         banner.setHref(relativizeLink(banner.getHref(), baseUrl));
         banner.setSrc(relativizeLink(banner.getSrc(), baseUrl));
     }
 
     private void rebaseBannerPaths(final Banner banner, final URLRebaser urlContainer) {
         if (banner.getHref() != null) // it may be empty
         {
             banner.setHref(urlContainer.rebaseLink(banner.getHref()));
         }
 
         if (banner.getSrc() != null) {
             banner.setSrc(urlContainer.rebaseLink(banner.getSrc()));
         }
     }
 
     private void assembleCustomInheritance(final SiteModel child, final SiteModel parent) {
         if (child.getCustom() == null) {
             child.setCustom(parent.getCustom());
         } else {
             child.setCustom(Xpp3Dom.mergeXpp3Dom((Xpp3Dom) child.getCustom(), (Xpp3Dom) parent.getCustom()));
         }
     }
 
     private void assembleBodyInheritance(
             final String name, final SiteModel child, final SiteModel parent, final URLRebaser urlContainer) {
         Body cBody = child.getBody();
         Body pBody = parent.getBody();
 
         if (cBody != null || pBody != null) {
             if (cBody == null) {
                 cBody = new Body();
                 child.setBody(cBody);
             }
 
             if (pBody == null) {
                 pBody = new Body();
             }
 
             if (cBody.getHead() == null && pBody.getHead() != null) {
                 cBody.setHead(pBody.getHead());
             }
 
             cBody.setLinks(mergeLinkItemLists(cBody.getLinks(), pBody.getLinks(), urlContainer, false));
 
             if (cBody.getBreadcrumbs().isEmpty() && !pBody.getBreadcrumbs().isEmpty()) {
                 LinkItem breadcrumb = new LinkItem();
                 breadcrumb.setName(name);
                 breadcrumb.setHref("index.html");
                 cBody.getBreadcrumbs().add(breadcrumb);
             }
             cBody.setBreadcrumbs(
                     mergeLinkItemLists(cBody.getBreadcrumbs(), pBody.getBreadcrumbs(), urlContainer, true));
 
             cBody.setMenus(mergeMenus(cBody.getMenus(), pBody.getMenus(), urlContainer));
 
             if (cBody.getFooter() == null && pBody.getFooter() != null) {
                 cBody.setFooter(pBody.getFooter());
             }
         }
     }
 
     private List<Menu> mergeMenus(
             final List<Menu> childMenus, final List<Menu> parentMenus, final URLRebaser urlContainer) {
         List<Menu> menus = new ArrayList<Menu>(childMenus.size() + parentMenus.size());
 
         for (Menu menu : childMenus) {
             menus.add(menu);
         }
 
         int topCounter = 0;
         for (Menu menu : parentMenus) {
             if ("top".equals(menu.getInherit())) {
                 final Menu clone = menu.clone();
 
                 rebaseMenuPaths(clone.getItems(), urlContainer);
 
                 menus.add(topCounter, clone);
                 topCounter++;
             } else if ("bottom".equals(menu.getInherit())) {
                 final Menu clone = menu.clone();
 
                 rebaseMenuPaths(clone.getItems(), urlContainer);
 
                 menus.add(clone);
             }
         }
 
         return menus;
     }
 
     private void relativizeMenuPaths(final List<MenuItem> items, final String baseUrl) {
         for (MenuItem item : items) {
             relativizeLinkItemPaths(item, baseUrl);
             relativizeMenuPaths(item.getItems(), baseUrl);
         }
     }
 
     private void rebaseMenuPaths(final List<MenuItem> items, final URLRebaser urlContainer) {
         for (MenuItem item : items) {
             rebaseLinkItemPaths(item, urlContainer);
             rebaseMenuPaths(item.getItems(), urlContainer);
         }
     }
 
     private void relativizeLinkItemPaths(final LinkItem item, final String baseUrl) {
         item.setHref(relativizeLink(item.getHref(), baseUrl));
     }
 
     private void rebaseLinkItemPaths(final LinkItem item, final URLRebaser urlContainer) {
         item.setHref(urlContainer.rebaseLink(item.getHref()));
     }
 
     private void relativizeLogoPaths(final Logo logo, final String baseUrl) {
         logo.setImg(relativizeLink(logo.getImg(), baseUrl));
         relativizeLinkItemPaths(logo, baseUrl);
     }
 
     private void rebaseLogoPaths(final Logo logo, final URLRebaser urlContainer) {
         logo.setImg(urlContainer.rebaseLink(logo.getImg()));
         rebaseLinkItemPaths(logo, urlContainer);
     }
 
     private List<LinkItem> mergeLinkItemLists(
             final List<LinkItem> childList,
             final List<LinkItem> parentList,
             final URLRebaser urlContainer,
             boolean cutParentAfterDuplicate) {
         List<LinkItem> items = new ArrayList<LinkItem>(childList.size() + parentList.size());
 
         for (LinkItem item : parentList) {
             if (!items.contains(item) && !childList.contains(item)) {
                 final LinkItem clone = item.clone();
 
                 rebaseLinkItemPaths(clone, urlContainer);
 
                 items.add(clone);
             } else if (cutParentAfterDuplicate) {
                 // if a parent item is found in child, ignore next items (case for breadcrumbs)
                 // merge ( "B > E", "A > B > C > D" ) -> "A > B > E" (notice missing "C > D")
                 // see https://issues.apache.org/jira/browse/DOXIASITETOOLS-62
                 break;
             }
         }
 
         for (LinkItem item : childList) {
             if (!items.contains(item)) {
                 items.add(item);
             }
         }
 
         return items;
     }
 
     private List<Logo> mergePoweredByLists(
             final List<Logo> childList, final List<Logo> parentList, final URLRebaser urlContainer) {
         List<Logo> logos = new ArrayList<Logo>(childList.size() + parentList.size());
 
         for (Logo logo : parentList) {
             if (!logos.contains(logo)) {
                 final Logo clone = logo.clone();
 
                 rebaseLogoPaths(clone, urlContainer);
 
                 logos.add(clone);
             }
         }
 
         for (Logo logo : childList) {
             if (!logos.contains(logo)) {
                 logos.add(logo);
             }
         }
 
         return logos;
     }
 
     // relativize only affects absolute links, if the link has the same scheme, host and port
     // as the base, it is made into a relative link as viewed from the base
     private String relativizeLink(final String link, final String baseUri) {
         if (link == null || baseUri == null) {
             return link;
         }
 
         // this shouldn't be necessary, just to swallow mal-formed hrefs
         try {
             final URIPathDescriptor path = new URIPathDescriptor(baseUri, link);
 
             return path.relativizeLink().toString();
         } catch (IllegalArgumentException e) {
             return link;
         }
     }
 
     /**
      * URL rebaser: based on an old and a new path, can rebase a link based on old path to a value based on the new
      * path.
      */
     private static class URLRebaser {
 
         private final String oldPath;
 
         private final String newPath;
 
         /**
          * Construct a URL rebaser.
          *
          * @param oldPath the old path.
          * @param newPath the new path.
          */
         URLRebaser(final String oldPath, final String newPath) {
             this.oldPath = oldPath;
             this.newPath = newPath;
         }
 
         /**
          * Get the new path.
          *
          * @return the new path.
          */
         public String getNewPath() {
             return this.newPath;
         }
 
         /**
          * Get the old path.
          *
          * @return the old path.
          */
         public String getOldPath() {
             return this.oldPath;
         }
 
         /**
          * Rebase only affects relative links, a relative link wrt an old base gets translated,
          * so it points to the same location as viewed from a new base
          */
         public String rebaseLink(final String link) {
             if (link == null || getOldPath() == null) {
                 return link;
             }
 
             if (link.contains("${project.")) {
                 throw new IllegalArgumentException("site.xml late interpolation ${project.*} expression found"
                         + " in link: '" + link + "'. Use early interpolation ${this.*}");
             }
 
             final URIPathDescriptor oldPath = new URIPathDescriptor(getOldPath(), link);
 
             return oldPath.rebaseLink(getNewPath()).toString();
         }
     }
 }