/*
    * 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.devacfr.maven.skins.reflow.model;
  
  import javax.annotation.Nonnull;
  import javax.annotation.Nullable;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  import com.google.common.base.Strings;
  import com.google.common.collect.Lists;
  import org.apache.commons.lang3.builder.ToStringBuilder;
  import org.codehaus.plexus.util.xml.Xpp3Dom;
  import org.devacfr.maven.skins.reflow.ISkinConfig;
  import org.devacfr.maven.skins.reflow.SkinConfigTool;
  import org.devacfr.maven.skins.reflow.Xpp3Utils;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Represents the navside menu component used in document page.
   * <p>
   * A sample configuration would be like that:
   * </p>
   *
   * <pre>
   * {@code
   * <custom>
   *   <reflowSkin>
   *     <pages>
   *       <document type="doc">
   *          <menu name="Documentation" selectFirstOnExpand="true">
   *              <item name="Get Started" href="get-started.html" />
   *              <item name="Layouts">
   *                  <item name="Overview" href="layouts.html" />
   *                  <item name="Body" href="body.html" />
   *              </item>
   *              <item name="Migration" href="migration.html" />
   *          </menu>
   *       </document>
   *     </pages>
   *   </reflowSkin>
   * </custom>
   * }∂
   * </pre>
   *
   * @author Christophe Friederich
   * @since 2.0
   */
  public class NavSideMenu extends BsComponent {
  
      /** */
      private static final String COMPONENT = "navside-menu";
  
      /** */
      private static final String MENU_COMPONENT = "menu";
  
      /** */
      private String name;
  
      /** */
      private List<SideNavMenuItem> items;
  
      /** */
      private boolean selectFirstOnExpand = false;
  
      /**
       * Find all {@link SideNavMenuItem sidenav menu items} declared in all document pages.
       *
       * @param config
       *            a config (can <b>not</b> be {@code null}).
       * @return Returns a list of all all {@link SideNavMenuItem sidenav menu items} declared in all document pages
       *         (returns list can <b>not</b> be {@code null}).
       */
      @Nonnull
      public static List<SideNavMenuItem> findAllSideNavMenuItems(@Nonnull final ISkinConfig config) {
          requireNonNull(config);
          final Xpp3Dom pagesNode = Xpp3Utils.getFirstChild(config.getGlobalProperties(), "pages", config.getNamespace());
          if (pagesNode == null) {
              return Collections.emptyList();
          }
         final Xpp3Dom[] pages = pagesNode.getChildren();
         final List<SideNavMenuItem> includePages = new ArrayList<>();
         for (final Xpp3Dom page : pages) {
             final String type = page.getAttribute("type");
             if ("doc".equals(type)) {
                 // This allows preventing accidental reuse of child page in other module of
                 // project
                 final String projectId = page.getAttribute("project");
                 if (!Strings.isNullOrEmpty(projectId) && !projectId.equals(config.getProjectId())) {
                     continue;
                 }
                 final Xpp3Dom menu = page.getChild(MENU_COMPONENT);
                 if (menu == null) {
                     continue;
                 }
                 final String pageName = page.getName();
                 // create a flatten list containing all menuItem.
                 addMenuItemRecursively(includePages, config, menu, pageName, true);
             }
         }
         return includePages;
     }
 
     /**
      * Default constructor.
      *
      * @param config
      *            a config (can <b>not</b> be {@code null}).
      */
     public NavSideMenu(@Nonnull final ISkinConfig config) {
         super("navside");
         requireNonNull(config);
         final Xpp3Dom pageNode = config.getPageProperties();
         final Xpp3Dom menu = pageNode.getChild(MENU_COMPONENT);
         final List<SideNavMenuItem> items = Lists.newArrayList();
         if (menu != null) {
             final String pageName = pageNode.getName();
             addMenuItemRecursively(items, config, menu, pageName, false);
 
             this.withName(menu.getAttribute("name"))
                     .withItems(items)
                     .withSelectFirstOnSelect(
                         config.getAttributeValue(MENU_COMPONENT, "selectFirstOnExpand", Boolean.class, true));
             this.setTheme(config.getAttributeValue(COMPONENT, "theme", String.class, "light"));
             this.setBackground(config.getAttributeValue(COMPONENT, "background", String.class, "light"));
             this.setCssClass(config.getAttributeValue(COMPONENT, "cssClass", String.class, null));
         }
         this.addCssOptions("m-sidenav-enabled");
         if (isSelectFirstOnExpand()) {
             this.addCssOptions("m-sidenav-select-first-on-select");
         }
     }
 
     /**
      * Gets the name of menu displayed on top of navside menu.
      *
      * @return Returns a {@link String} representing the name of menu.
      */
     @Nullable public String getName() {
         return name;
     }
 
     /**
      * Sets the name of menu displayed on top of navside menu.
      *
      * @param name
      *            the name to use.
      * @return Returns the fluent instance.
      */
     protected NavSideMenu withName(final String name) {
         this.name = name;
         return this;
     }
 
     /**
      * Gets the indicating whether menu contains a least one menu item.
      *
      * @return Returns {@code true} whether menu contains a least one menu item, otherwise returns {@code false}.
      */
     public boolean isHasItems() {
         return items != null && !items.isEmpty();
     }
 
     /**
      * @return Returns the {@link List} of {@link SideNavMenuItem} containing in {@code <menu> element}.
      */
     @Nonnull
     public List<SideNavMenuItem> getItems() {
         return items;
     }
 
     /**
      * Sets the {@link List} of {@link SideNavMenuItem}.
      *
      * @param items
      *            list of items to use.
      * @return Returns the fluent instance.
      */
     protected NavSideMenu withItems(final List<SideNavMenuItem> items) {
         this.items = items;
         return this;
     }
 
     /**
      * Gets the indicating whether the first sub menu item should be selected when a dropdown menu item is selected and
      * should expand.
      *
      * @return Returns {@code true} whether the first sub menu item should be selected when a dropdown menu item is
      *         selected and expanded, otherwise returns {@code false}.
      */
     public boolean isSelectFirstOnExpand() {
         return selectFirstOnExpand;
     }
 
     /**
      * Sets the indicating whether the first sub menu item should be selected when a dropdown menu item is selected and
      * should expand.
      *
      * @param selectFirstOnExpand
      *            a value to use.
      * @return Returns the fluent instance.
      */
     protected NavSideMenu withSelectFirstOnSelect(final boolean selectFirstOnExpand) {
         this.selectFirstOnExpand = selectFirstOnExpand;
         return this;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String toString() {
         return ToStringBuilder.reflectionToString(this);
     }
 
     /**
      * @param menuItems
      * @param parentNode
      * @param pageName
      * @param flatten
      */
     private static void addMenuItemRecursively(@Nonnull final List<SideNavMenuItem> menuItems,
         @Nonnull final ISkinConfig config,
         @Nonnull final Xpp3Dom parentNode,
         @Nonnull final String pageName,
         final boolean flatten) {
         for (final Xpp3Dom item : Xpp3Utils.getChildrenNodes(parentNode, "item")) {
             final String href = item.getAttribute("href");
             final SideNavMenuItem menuItem = new SideNavMenuItem().withName(item.getAttribute("name"))
                     .withParent(pageName)
                     .withHref(config.relativeLink(href))
                     .withSlugName(SkinConfigTool.slugFilename(href))
                     .withIcon(item.getAttribute("icon"));
             menuItems.add(menuItem);
             if (flatten) {
                 addMenuItemRecursively(menuItems, config, item, pageName, true);
             } else {
                 final List<SideNavMenuItem> list = new ArrayList<>();
                 menuItem.withItems(list);
                 addMenuItemRecursively(list, config, item, pageName, false);
             }
         }
     }
 }