// Copyright 2012 Google Inc. All Rights Reserved.
//
// Licensed 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 com.google.collide.client.code.autocomplete;

import com.google.collide.json.shared.JsonArray;
import com.google.collide.shared.util.JsonCollections;

/**
 * A node in a trie that can be used for efficient autocompletion lookup.
 *
 * @param <T> value object type
 */
public final class TrieNode<T> {
  private final String prefix;
  private final JsonArray<TrieNode<T>> children;
  private T value;

  private TrieNode(String prefix) {
    this.prefix = prefix;
    this.value = null;
    this.children = JsonCollections.createArray();
  }

  public static <T> TrieNode<T> makeNode(String prefix) {
    return new TrieNode<T>(prefix);
  }

  public JsonArray<TrieNode<T>> getChildren() {
    return children;
  }

  TrieNode<T> findInsertionBranch(String prefix) {
    for (int i = 0, size = children.size(); i < size; i++) {
      TrieNode<T> child = children.get(i);
      if (prefix.startsWith(child.getPrefix())) {
        return child;
      }
    }
    return null;
  }

  public void addChild(TrieNode<T> child) {
    children.add(child);
  }

  public boolean getIsLeaf() {
    return this.value != null;
  }

  public String getPrefix() {
    return this.prefix;
  }

  public void setValue(T value) {
    this.value = value;
  }

  public T getValue() {
    return this.value;
  }

  @Override
  public String toString() {
    return this.prefix;
  }
}
