package org.sxkj.system.util;

import org.springframework.util.CollectionUtils;
import org.sxkj.system.entity.DictBiz;

import java.util.*;

public class LevelDataMerger {


	/**
	 * 按层级分组的数据，key为层级(从0开始)，value为该层所有节点
	 *
	 * @param list
	 * @return
	 */
	public static Map<Integer, List<DictBiz>> buildMap(List<DictBiz> list) {
		if(CollectionUtils.isEmpty(list)) {
			return Collections.emptyMap();
		}
		List<DictBiz> listzz = TreeBuilder.buildTree(list);
		if (CollectionUtils.isEmpty(listzz)) {
			return Collections.emptyMap();
		}
		return mergeByLevel(listzz);
	}

	/**
	 * 按层级合并树形结构数据
	 *
	 * @param tree 树形结构数据
	 * @return 按层级分组的数据，key为层级(从0开始)，value为该层所有节点
	 */
	public static Map<Integer, List<DictBiz>> mergeByLevel(List<DictBiz> tree) {
		Map<Integer, List<DictBiz>> levelMap = new LinkedHashMap<>();
		traverseTree(tree, 0, levelMap);
		return levelMap;
	}

	/**
	 * 递归遍历树形结构
	 *
	 * @param nodes    当前层节点
	 * @param level    当前层级
	 * @param levelMap 结果存储Map
	 */
	private static void traverseTree(List<DictBiz> nodes, int level, Map<Integer, List<DictBiz>> levelMap) {
		if (nodes == null || nodes.isEmpty()) {
			return;
		}

		// 获取或创建当前层级的List
		List<DictBiz> currentLevelList = levelMap.computeIfAbsent(level, k -> new ArrayList<>());

		// 将当前层所有节点添加到对应层级的List中
		currentLevelList.addAll(nodes);

		// 递归处理每个节点的子节点
		for (DictBiz node : nodes) {
			if (node.getChildrenList() != null && !node.getChildrenList().isEmpty()) {
				traverseTree(node.getChildrenList(), level + 1, levelMap);
			}
		}
	}

	/**
	 * 非递归方式实现层级合并（广度优先遍历）
	 *
	 * @param tree 树形结构数据
	 * @return 按层级分组的数据
	 */
	public static Map<Integer, List<DictBiz>> mergeByLevelBFS(List<DictBiz> tree) {
		Map<Integer, List<DictBiz>> levelMap = new LinkedHashMap<>();
		if (tree == null || tree.isEmpty()) {
			return levelMap;
		}

		List<DictBiz> currentLevel = new ArrayList<>(tree);
		int level = 0;

		while (!currentLevel.isEmpty()) {
			// 添加当前层级节点
			levelMap.put(level, new ArrayList<>(currentLevel));

			// 准备下一层级节点
			List<DictBiz> nextLevel = new ArrayList<>();
			for (DictBiz node : currentLevel) {
				if (node.getChildrenList() != null) {
					nextLevel.addAll(node.getChildrenList());
				}
			}

			currentLevel = nextLevel;
			level++;
		}

		return levelMap;
	}
}