package cn.teammodel.service.impl;

import cn.hutool.core.lang.UUID;
import cn.teammodel.common.ErrorCode;
import cn.teammodel.common.PK;
import cn.teammodel.config.exception.ServiceException;
import cn.teammodel.dao.EvaluationRepository;
import cn.teammodel.model.dto.DeleteNodeDto;
import cn.teammodel.model.dto.GetEvaluateTreeDto;
import cn.teammodel.model.dto.InsertNodeDto;
import cn.teammodel.model.dto.UpdateNodeDto;
import cn.teammodel.model.entity.Appraise;
import cn.teammodel.model.entity.AppraiseTreeNode;
import cn.teammodel.model.entity.User;
import cn.teammodel.security.utils.SecurityUtils;
import cn.teammodel.service.EvaluationService;
import com.azure.spring.data.cosmos.core.CosmosTemplate;
import org.apache.commons.lang3.ObjectUtils;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.BeanUtils;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.List;

/**
 * @author winter
 * @create 2023-11-20 17:47
 */
@Service
public class EvaluationServiceImpl implements EvaluationService {
    @Resource
    CosmosTemplate cosmosTemplate;
    @Resource
    private EvaluationRepository evaluationRepository;

    /**
     * 通用的获取 evaluation 的方法: 判断参数,判断数据是否为空 <br/>
     * 从 token 中获取 schoolId
     */
    private Appraise findAppraise(String periodId) {
        // 默认学区为 default
        periodId = StringUtils.isEmpty(periodId) ? "default" : periodId;
        User loginUser = SecurityUtils.getLoginUser();
        String schoolId = loginUser.getSchoolId();

        // 拿到要新增节点的原始数据
        Appraise appraise = evaluationRepository.findAppraiseBySchoolIdAndPeriodIdAndCode(schoolId, periodId, PK.PK_APPRAISE);
        if (appraise == null) {
            throw new ServiceException(ErrorCode.PARAMS_ERROR.getCode(), "学校评价数据不存在");
        }
        return appraise;
    }

    @Override
    public Appraise getTree(GetEvaluateTreeDto getEvaluateTreeDto) {
        Appraise appraise = findAppraise(getEvaluateTreeDto.getPeriodId());

        return this.buildTree(appraise);
    }

    @Override
    public Appraise buildTree(Appraise appraise) {
        if (appraise == null) {
            return null;
        }

        List<AppraiseTreeNode> nodes = appraise.getNodes();
        List<AppraiseTreeNode> parents = new ArrayList<>();

        // pid 为 null 或者 "" 则为 parents
        for (AppraiseTreeNode node : nodes) {
            if (StringUtils.isBlank(node.getPid())) {
                parents.add(node);
            }
        }
        // 迭代构建孩子节点
        for (AppraiseTreeNode parent : parents) {
            buildChildren(parent, nodes);
        }
        appraise.setNodes(parents);
        return appraise;
    }

    @Override
    public void flattenTree(List<AppraiseTreeNode> trees, List<AppraiseTreeNode> nodes) {
        // 递归结束条件
        if (ObjectUtils.isEmpty(trees)) return;

        // 这里的每个 tree 都是组装好的树,区别于单个节点
        for (AppraiseTreeNode tree : trees) {
            // 递归
            flattenTree(tree.getChildren(), nodes);
            // 回溯时删除 children,添加进列表
            tree.setChildren(null);
            nodes.add(tree);
        }
    }

    @Override
    public Appraise insertNode(InsertNodeDto insertNodeDto) {
        Appraise appraise = findAppraise(insertNodeDto.getPeriodId());
        User loginUser = SecurityUtils.getLoginUser();

        List<AppraiseTreeNode> originNodes = appraise.getNodes();
        // 拷贝数据到新节点
        AppraiseTreeNode newNode = new AppraiseTreeNode();
        BeanUtils.copyProperties(insertNodeDto, newNode);

        String newNodePid = newNode.getPid();
        // 根节点直接添加
        if (StringUtils.isNotEmpty(newNodePid)) {
            boolean invalid = originNodes.stream().noneMatch(item -> newNodePid.equals(item.getId()));
            if (invalid) {
                throw new ServiceException(ErrorCode.PARAMS_ERROR.getCode(), "父节点不存在");
            }
        }
        // todo: 可不可以添加默认值 order ?
        newNode.setId(UUID.randomUUID().toString());
        newNode.setCreatorId(loginUser.getId());
        newNode.setCreator(loginUser.getName());
        newNode.setCreateTime(LocalDateTime.now());

        originNodes.add(newNode);
        return buildTree(evaluationRepository.save(appraise));
    }

    @Override
    public Appraise updateNode(UpdateNodeDto updateNodeDto) {
        String updateNodeId = updateNodeDto.getId();

        Appraise appraise = findAppraise(updateNodeDto.getPeriodId());
        List<AppraiseTreeNode> originNodes = appraise.getNodes();
        // 每个节点都有 id, 直接校验是否合法
        AppraiseTreeNode updateNode = originNodes.stream()
                .filter(item -> updateNodeId.equals(item.getId()))
                .findFirst()
                .orElseThrow(() -> new ServiceException(ErrorCode.PARAMS_ERROR.getCode(), "更新节点不存在"));
        // 更新字段,考虑直接 copy properties
        updateNode.setName(updateNodeDto.getName());
        updateNode.setLogo(updateNodeDto.getLogo());
        updateNode.setOrder(updateNodeDto.getOrder());
        updateNode.setPraise(updateNodeDto.isPraise());
        // todo: 为新节点赋值必须参数 (id, creator), 可不可以添加默认值 order ?

        return buildTree(evaluationRepository.save(appraise));
    }

    @Override
    public Appraise deleteNode(DeleteNodeDto deleteNodeDto) {
        // 删除指定节点,可能是(一级,二级,三级),设计一个通用的
        Appraise appraise = findAppraise(deleteNodeDto.getPeriodId());
        List<AppraiseTreeNode> nodes = appraise.getNodes();
        List<AppraiseTreeNode> nodesToDelete = new ArrayList<>();

        // 迭代器安全删除
        for (AppraiseTreeNode node : nodes) {
            if (node.getId().equals(deleteNodeDto.getId())) {
                // 删除当前节点
                nodesToDelete.add(node);
                // 递归删除其孩子节点
                this.collectNodesToDelete(node.getId(), nodes, nodesToDelete);
            }
        }
        nodes.removeAll(nodesToDelete);

        return buildTree(evaluationRepository.save(appraise));
    }

    /**
    * 递归收集 id 的节点及 id 节点的孩子节点 (迭代器删除居然也报错)
    */
    private void collectNodesToDelete(String id, List<AppraiseTreeNode> nodes, List<AppraiseTreeNode> nodesToDelete) {
        for (AppraiseTreeNode node : nodes) {
            if (id.equals(node.getPid())) {
                // 收集
                nodesToDelete.add(node);
                // 递归收集
                collectNodesToDelete(node.getId(), nodes, nodesToDelete);
            }
        }

    }

    /**
     * 递归的构建父亲节点的孩子,以及孩子的孩子 (理论支持无极树,但应该考虑是否增加递归深度)
     */
    private void buildChildren(AppraiseTreeNode parent, List<AppraiseTreeNode> nodes) {
        List<AppraiseTreeNode> children = getChildren(parent, nodes);
        if (children.size() == 0) return;

        parent.setChildren(children);
        for (AppraiseTreeNode child : children) {
            // 如果子节点还有孩子的话,就继续递归构建
            if (getChildren(child, nodes).size() > 0) {
                buildChildren(child, nodes);
            }
        }

    }


    /**
    * 获取节点的孩子节点列表
    */
    private List<AppraiseTreeNode> getChildren(AppraiseTreeNode parent, List<AppraiseTreeNode> nodes) {
        List<AppraiseTreeNode> children = new ArrayList<>();
        for (AppraiseTreeNode node : nodes) {
            if (StringUtils.isNotBlank(node.getPid()) && node.getPid().equals(parent.getId())) {
                children.add(node);
            }
        }
        return children;
    }
}