/*
    * 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.model;
  
  import javax.swing.tree.TreeNode;
  import java.io.Serializable;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Set;
  
  /**
   * Manages the expanded state of an tree.
   *
   * @since 1.6.0
   */
  public class ExpandedState implements Serializable {
  
    private int defaultExpandedLevels;
    private Set<TreePath> expandedSet;
    private Set<TreePath> collapsedSet;
  
    /**
     * Creates a new state object to store which nodes of a tree are expanded and collapsed in a view.
     *
     * @param defaultExpandedLevels All nodes up to this level are expanded by default.
     */
    public ExpandedState(int defaultExpandedLevels) {
      this.defaultExpandedLevels = defaultExpandedLevels;
      this.expandedSet = new HashSet<TreePath>();
      this.collapsedSet = new HashSet<TreePath>();
    }
  
    /**
     * Checks if a node is expanded.
     *
     * @param node The node to check.
     * @return Is the node expanded?
     */
    public boolean isExpanded(TreeNode node) {
      final TreePath path = new TreePath(node);
      return isExpanded(path);
    }
  
    /**
     * Checks if a node is expanded.
     *
     * @param path The path of the node to check.
     * @return Is the node behind this path is expanded?
     */
    public boolean isExpanded(TreePath path) {
      if (expandedSet.contains(path)) {
        return true;
      }
      if (collapsedSet.contains(path)) {
        return false;
      }
      return path.getLength() < defaultExpandedLevels;
    }
  
    /**
     * Expands a single node.
     *
     * @param node The node to expand.
     */
    public void expand(TreeNode node) {
      final TreePath path = new TreePath(node);
      expand(path);
    }
  
    /**
     * Expands a single node.
     *
     * @param path The path of the node to expand.
     */
    public void expand(TreePath path) {
      if (path.getLength() >= defaultExpandedLevels) {
        expandedSet.add(path);
      } else {
        collapsedSet.remove(path);
      }
    }
 
   /**
    * Expands all nodes that level are lower or equals the parameter level.
    *
    * @param level The level to expand.
    */
   public void expand(int level) {
     ArrayList<TreePath> toRemove = new ArrayList<TreePath>();
     if (level > defaultExpandedLevels) {
       defaultExpandedLevels = level;
       for (TreePath treePath : expandedSet) {
         if (treePath.getLength() < defaultExpandedLevels) {
           toRemove.add(treePath);
         }
       }
       expandedSet.removeAll(toRemove);
       collapsedSet.clear();
     } else {
       for (TreePath treePath : collapsedSet) {
         if (treePath.getLength() < level) {
           toRemove.add(treePath);
         }
       }
       collapsedSet.removeAll(toRemove);
     }
   }
 
   /**
    * Expands a nodes of the tree.
    */
   public void expandAll() {
     defaultExpandedLevels = Integer.MAX_VALUE;
     expandedSet.clear();
     collapsedSet.clear();
   }
 
   /**
    * Collapses a single node.
    *
    * @param node The node to collapse.
    */
   public void collapse(TreeNode node) {
     final TreePath path = new TreePath(node);
     collapse(path);
   }
 
   /**
    * Collapses a single node.
    *
    * @param path The path of the node to collapse.
    */
   public void collapse(TreePath path) {
     if (path.getLength() < defaultExpandedLevels) {
       collapsedSet.add(path);
     } else {
       expandedSet.remove(path);
     }
   }
 
   /**
    * Collapses all nodes that level are higher or equals the parameter level.
    *
    * @param level The level to expand.
    */
   public void collapse(int level) {
     // to use a symmetric algorithm like in expand
     level--;
 
     ArrayList<TreePath> toRemove = new ArrayList<TreePath>();
     if (level < defaultExpandedLevels) {
       defaultExpandedLevels = level;
       for (TreePath treePath : collapsedSet) {
         if (treePath.getLength() >= defaultExpandedLevels) {
           toRemove.add(treePath);
         }
       }
       collapsedSet.removeAll(toRemove);
       expandedSet.clear();
     } else {
       for (TreePath treePath : expandedSet) {
         if (treePath.getLength() >= level) {
           toRemove.add(treePath);
         }
       }
       expandedSet.removeAll(toRemove);
     }
   }
 
   /**
    * Collapses a nodes of the tree.
    */
   public void collapseAll() {
     defaultExpandedLevels = 0;
     expandedSet.clear();
     collapsedSet.clear();
   }
 
   /**
    * Collapses a nodes of the tree. The root node will be expanded.
    */
   public void collapseAllButRoot() {
     defaultExpandedLevels = 1;
     expandedSet.clear();
     collapsedSet.clear();
   }
 
   /**
    * Resets the state to the defaults. After this call, the nodes with level smaller than defaultExpandedLevels
    * are expanded, the other ones are collapsed.
    */
   public void reset() {
     expandedSet.clear();
     collapsedSet.clear();
   }
 
   /**
    * @return A unmodifiable set of paths of the expanded nodes.
    */
   public Set<TreePath> getExpandedSet() {
     return Collections.unmodifiableSet(expandedSet);
   }
 
   /**
    * @return A unmodifiable set of paths of the collapsed nodes.
    */
   public Set<TreePath> getCollapsedSet() {
     return Collections.unmodifiableSet(collapsedSet);
   }
 }