content: /*
   * Copyright 2024-2026 the original author or authors.
   *
   * 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
   *
   *     https://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.cloud.ai.graph.internal.node;
  
  import com.alibaba.cloud.ai.graph.CompileConfig;
  import com.alibaba.cloud.ai.graph.OverAllState;
  import com.alibaba.cloud.ai.graph.StateGraph;
  import com.alibaba.cloud.ai.graph.action.AsyncNodeActionWithConfig;
  import com.alibaba.cloud.ai.graph.exception.Errors;
  import com.alibaba.cloud.ai.graph.exception.GraphStateException;
  
  import java.util.Objects;
  import java.util.function.Function;
  
  import static java.lang.String.format;
  
  /**
   * Represents a node in a graph, characterized by a unique identifier and a factory for
   * creating actions to be executed by the node. This is a generic record where the state
   * type is specified by the type parameter {@code State}.
   *
   * {@link OverAllState}.
   *
   */
  public class Node {
  
  	public static final String PRIVATE_PREFIX = "__";
  
  	public interface ActionFactory {
  
  		AsyncNodeActionWithConfig apply(CompileConfig config) throws GraphStateException;
  
  	}
  
  	private final String id;
  
  	private final ActionFactory actionFactory;
  
  	public Node(String id, ActionFactory actionFactory) {
  		this.id = id;
  		this.actionFactory = actionFactory;
  	}
  
  	/**
  	 * Constructor that accepts only the `id` and sets `actionFactory` to null.
  	 * @param id the unique identifier for the node
  	 */
  	public Node(String id) {
  		this(id, null);
  	}
  
  	public void validate() throws GraphStateException {
  		if (Objects.equals(id, StateGraph.END) || Objects.equals(id, StateGraph.START)) {
  			return;
  		}
  
  		if (id.isBlank()) {
  			throw Errors.invalidNodeIdentifier.exception("blank node id");
  		}
  
  		if (id.startsWith(PRIVATE_PREFIX)) {
  			throw Errors.invalidNodeIdentifier.exception("id that start with %s", PRIVATE_PREFIX);
  		}
  	}
  
  	/**
  	 * id
  	 * @return the unique identifier for the node.
  	 */
  	public String id() {
  		return id;
  	}
  
  	/**
  	 * actionFactory
  	 * @return a factory function that takes a {@link CompileConfig} and returns an
  	 * {@link AsyncNodeActionWithConfig} instance for the specified {@code State}.
  	 */
  	public ActionFactory actionFactory() {
  		return actionFactory;
  	}
  
  	public boolean isParallel() {
  		// return id.startsWith(PARALLEL_PREFIX);
  		return false;
  	}
  
  	public Node withIdUpdated(Function<String, String> newId) {
  		return new Node(newId.apply(id), actionFactory);
  	}
  
  	/**
  	 * Checks if this node is equal to another object.
  	 * @param o the object to compare with
  	 * @return true if this node is equal to the specified object, false otherwise
  	 */
  	@Override
  	public boolean equals(Object o) {
  		if (this == o)
  			return true;
  		if (o == null)
  			return false;
  		if (o instanceof Node node) {
  			return Objects.equals(id, node.id);
  		}
  		return false;
  
  	}
  
  	/**
  	 * Returns the hash code value for this node.
  	 * @return the hash code value for this node
  	 */
  	@Override
  	public int hashCode() {
  		return Objects.hash(id);
  	}
  
  	@Override
  	public String toString() {
  		return format("Node(%s,%s)", id, actionFactory != null ? "action" : "null");
  	}
  
  }
  