/*
    * 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.myfaces.tobago.example.demo;
  
  import org.apache.myfaces.tobago.model.ExpandedState;
  import org.apache.myfaces.tobago.model.SelectedState;
  import org.apache.myfaces.tobago.model.TreePath;
  import org.apache.myfaces.tobago.model.TreeState;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import javax.annotation.PostConstruct;
  import javax.enterprise.context.SessionScoped;
  import javax.enterprise.event.Observes;
  import javax.faces.context.FacesContext;
  import javax.inject.Inject;
  import javax.inject.Named;
  import java.io.Serializable;
  import java.lang.invoke.MethodHandles;
  
  @SessionScoped
  @Named
  public class NavigationState implements Serializable {
  
    private static final Logger LOG = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
  
    @Inject
    private NavigationTree tree;
  
    private NavigationNode currentNode;
  
    private TreeState state = new TreeState(new ExpandedState(1), new SelectedState());
  
    private boolean viewSource = false;
  
    @PostConstruct
    public void init() {
      currentNode = tree.findByViewId(FacesContext.getCurrentInstance().getViewRoot().getViewId());
      initState();
    }
  
    private void initState() {
      if (currentNode != null) {
        final TreePath treePath = currentNode.getTreePath();
        state.getSelectedState().clearAndSelect(treePath);
        if (!treePath.isRoot()) {
        state.getExpandedState().collapseAllButRoot();
          state.getExpandedState().expand(treePath, true);
        }
      }
    }
  
    public NavigationNode getCurrentNode() {
      return currentNode;
    }
  
    public String gotoFirst() {
      return gotoNode(tree.getTree().getNextNode()) + "?faces-redirect=true"; // the first after the root node
    }
  
    public String gotoPrevious() {
      if (currentNode == null) {
        return gotoFirst();
      } else {
        final NavigationNode previousNode = currentNode.getPreviousNode();
        if (previousNode != null) {
          return gotoNode(previousNode);
        } else {
          LOG.warn("Strange navigation behavior");
          return null;
        }
      }
    }
  
    public String gotoNext() {
      if (currentNode == null) {
        return gotoFirst();
      } else {
        final NavigationNode nextNode = currentNode.getNextNode();
        if (nextNode != null) {
          return gotoNode(nextNode);
        } else {
         LOG.warn("Strange navigation behavior");
         return null;
       }
     }
   }
 
   public String gotoNode(@Observes final NavigationNode node) {
     if (node == null) {
       return gotoFirst();
     } else {
       if (!node.equals(currentNode)) {
         currentNode = node;
         LOG.info("Navigate to '" + currentNode.getOutcome() + "'");
       }
       initState();
       return currentNode.getOutcome();
     }
   }
 
   public boolean isFirst() {
     if (currentNode == null) {
       return false;
     }
     final NavigationNode previousNode = currentNode.getPreviousNode();
     return previousNode == null || previousNode.isRoot();
   }
 
   public boolean isLast() {
     if (currentNode == null) {
       return false;
     }
     final NavigationNode nextNode = currentNode.getNextNode();
     return nextNode == null;
   }
 
   public TreeState getState() {
     return state;
   }
 
   public String toggleViewSource() {
     viewSource = !viewSource;
     return null;
   }
 
   public boolean isViewSource() {
     return viewSource;
   }
 
   public void setViewSource(final boolean viewSource) {
     this.viewSource = viewSource;
   }
 }