content: /**
   * Copyright (C) 2024 AIDC-AI
   *
   * 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.alibaba.langengine.core.chain.tot;
  
  import lombok.Data;
  
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * Tree of Thought (ToT) controller.
   * This is a version of a ToT controller, dubbed in the paper as a "Simple Controller".
   * It has one parameter `c` which is the number of children to explore for each thought.
   *
   * @author xiaoxuan.lp
   */
  @Data
  public class ToTController {
  
      private int c;
  
      public ToTController() {
          this(3);
      }
  
      public ToTController(int c) {
          this.c = c;
      }
  
      public List<String> call(ToTDFSMemory memory) {
          Thought nextThought = memory.top();
          Thought parentThought = memory.topParent();
          ThoughtValidity validity = (nextThought == null) ? ThoughtValidity.VALID_INTERMEDIATE : nextThought.getValidity();
  
          if (validity == ThoughtValidity.INVALID) {
              memory.pop();
              nextThought = memory.top();
              if (nextThought != null && nextThought.getChildren().size() >= c) {
                  memory.pop();
              }
          } else if (validity == ThoughtValidity.VALID_INTERMEDIATE && parentThought != null && parentThought.getChildren().size() >= c) {
              memory.pop(2);
          }
  
          List<Thought> currentPath = memory.getCurrentPath();
          List<String> texts = new ArrayList<>();
          for (int i = 0; i < currentPath.size(); i++) {
              texts.add(currentPath.get(i).getText());
          }
          return texts;
      }
  }
  