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.*;
import cn.teammodel.model.dto.Appraise.*;
import cn.teammodel.model.entity.User;
import cn.teammodel.model.entity.appraise.Appraise;
import cn.teammodel.model.entity.appraise.AppraiseRecord;
import cn.teammodel.model.entity.appraise.AppraiseRecordItem;
import cn.teammodel.model.entity.appraise.AppraiseTreeNode;
import cn.teammodel.model.entity.school.ClassInfo;
import cn.teammodel.model.entity.school.School;
import cn.teammodel.model.entity.school.Student;
import cn.teammodel.security.utils.SecurityUtil;
import cn.teammodel.service.EvaluationService;
import cn.teammodel.utils.RepositoryUtil;
import cn.teammodel.utils.SchoolDateUtil;
import com.azure.cosmos.models.CosmosPatchOperations;
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.LocalDate;
import java.time.LocalDateTime;
import java.util.*;
import java.util.stream.Collectors;

/**
 * @author winter
 * @create 2023-11-20 17:47
 */
@Service
public class EvaluationServiceImpl implements EvaluationService {
    /**
    * 评价记录对象的类型
    */
    private final static String TARGET_STUDENT = "student";
    private final static String TARGET_CLASS = "class";
    @Resource
    private ClassRepository classRepository;
    @Resource
    private StudentRepository studentRepository;
    @Resource
    private SchoolRepository schoolRepository;
    @Resource
    private AppraiseRecordRepository appraiseRecordRepository;
    @Resource
    private AppraiseRepository appraiseRepository;

    /**
     * 通用的获取用户学校和学段对应的 appraise 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 = SecurityUtil.getLoginUser();
        String schoolId = loginUser.getSchoolId();

        // 拿到要新增节点的原始数据
        Appraise appraise = appraiseRepository.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) {
        String periodId = getEvaluateTreeDto.getPeriodId();
        // 默认学区为 default
        periodId = StringUtils.isEmpty(periodId) ? "default" : periodId;
        User loginUser = SecurityUtil.getLoginUser();
        String schoolId = loginUser.getSchoolId();
        Appraise appraise = appraiseRepository.findAppraiseBySchoolIdAndPeriodIdAndCode(schoolId, periodId, PK.PK_APPRAISE);

        // todo: 是否要对学段进行鉴权
        if (appraise != null) {
            return this.buildTree(appraise);
        }
        // 如果传参 period 所在没有 tree 的话,则复制一份模板 tree 给他 (处理节点 id)
        appraise = RepositoryUtil.findOne(appraiseRepository.findTemplateTree(), "获取模板评价树失败");
        if (appraise == null) {
            throw new ServiceException();
        }
        refreshAppraiseTree(appraise.getNodes());
        appraise.setPeriodId(periodId);
        appraise.setSchoolId(schoolId);
        appraise.setId(null);
        appraise = appraiseRepository.save(appraise);
        return this.buildTree(appraise);
    }

    /**
    * 将树的节点的 id 进行替换(天才)
    */
    private void refreshAppraiseTree(List<AppraiseTreeNode> nodes) {
        List<AppraiseTreeNode> children = nodes.stream().filter(item -> item.getPid() != null).collect(Collectors.toList());
        // 将非 root 的 nodes 通过 pid 收集成 list, 再遍历 nodes, 将其每一个 id 对应 map 中的 list 的 pid修改成新的 id 即可
        Map<String, List<AppraiseTreeNode>> pidNodeMap = children.stream().collect(Collectors.groupingBy(AppraiseTreeNode::getPid));
        nodes.forEach(item -> {
            String newId = UUID.randomUUID().toString();
            String oldId = item.getId();
            List<AppraiseTreeNode> appraiseTreeNodes = pidNodeMap.get(oldId);
            if (appraiseTreeNodes != null) {
                appraiseTreeNodes.forEach(node -> node.setPid(newId));
            }
            // 处理每个节点属性
            item.setId(newId);
            item.setCreator("template");
        });

    }

    @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 = SecurityUtil.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(appraiseRepository.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(appraiseRepository.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);
            }
        }
        if (ObjectUtils.isEmpty(nodesToDelete)) {
            throw new ServiceException(ErrorCode.PARAMS_ERROR.getCode(), "删除节点不存在");
        }
        nodes.removeAll(nodesToDelete);

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

    @Override
    public void vote(AppraiseVoteDto appraiseVoteDto) {
        String targetId = appraiseVoteDto.getTargetId();
        boolean spread = appraiseVoteDto.isSpread();
        String targetType = appraiseVoteDto.getTargetType();
        String appraiseId = appraiseVoteDto.getAppraiseId();
        User loginUser = SecurityUtil.getLoginUser();
        String schoolId = loginUser.getSchoolId();
        String classId;
        String periodId;
        String name;
        String avatar = null;
        // 分别对班级和学生的关键信息取值
        if (targetType.equals(TARGET_STUDENT)) {
            Student student = studentRepository.findStudentByIdAndCode(targetId, String.format(PK.STUDENT, schoolId));
            if (student == null) {
                throw new ServiceException(ErrorCode.PARAMS_ERROR.getCode(), "该学生不存在");
            }
            classId = student.getClassId();
            periodId = student.getPeriodId();
            name = student.getName();
            avatar = student.getPicture();
        } else if (targetType.equals(TARGET_CLASS)){
            ClassInfo classInfo = classRepository.findClassByIdAndCode(targetId, String.format(PK.CLASS, schoolId));
            if (classInfo == null) {
                throw new ServiceException(ErrorCode.PARAMS_ERROR.getCode(), "班级不存在");
            }
            classId = targetId;
            periodId = classInfo.getPeriodId();
            name = classInfo.getName();
        } else {
            throw new ServiceException(ErrorCode.PARAMS_ERROR.getCode(), "不受支持的评价对象");
        }

        // 获取评价项节点
        List<AppraiseTreeNode> nodes = appraiseRepository.findNodeById(PK.PK_APPRAISE, appraiseId);
        AppraiseTreeNode appraiseTreeNode = RepositoryUtil.findOne(nodes, "获取评价项失败");

        // 通过 periodId 获取 semesters
        List<School.Period> periodById = schoolRepository.findPeriodById(schoolId, periodId);
        School.Period period = RepositoryUtil.findOne(periodById, "获取学段失败");
        List<School.Semester> semesters = period.getSemesters();

        // 获取当前学年学期组合 ID
        String academicYearId = SchoolDateUtil.generateAcademicId(semesters, LocalDate.now());

        // 查询是否存在记录
        AppraiseRecord record = appraiseRecordRepository.findAppraiseRecordByTargetIdAndClassIdAndAcademicYearIdAndCode(
                targetId,
                classId,
                academicYearId,
                String.format(PK.PK_APPRAISE_RECORD,schoolId)
        );

        // 初始化新的评价节点
        AppraiseRecordItem item = new AppraiseRecordItem();
        item.setId(UUID.randomUUID().toString());
        item.setAppraiseNode(appraiseTreeNode);
        item.setCreator(loginUser.getName());
        item.setCreatorId(loginUser.getId());
        item.setCreateTime(LocalDateTime.now());

        // 不存在或者学生的班级不一样则创建一条新的,存在则处理一下分值后再向其 nodes 中插入一条 item
        if (record == null || !classId.equals(record.getClassId())) {
            List<AppraiseRecordItem> items = Collections.singletonList(item);

            record = new AppraiseRecord();
            record.setTargetId(targetId);
            record.setTargetType(targetType);
            record.setClassId(classId);
            record.setName(name);
            record.setAvatar(avatar);
            record.setAcademicYearId(academicYearId);
            record.setPraiseCount(appraiseTreeNode.isPraise() ? 1 : -1);
            record.setScore(ObjectUtils.isEmpty(appraiseTreeNode.getScore()) ? 0 : appraiseTreeNode.getScore());
            record.setNodes(items);
            record.setCode(String.format(PK.PK_APPRAISE_RECORD, schoolId));
            appraiseRecordRepository.save(record);
        } else {
            // 处理学校与学生的差异
            if (targetType.equals(TARGET_CLASS)){
                item.setSpread(spread);
            }
            CosmosPatchOperations operations = CosmosPatchOperations.create();
            operations.add("/nodes/0", item);
            // 表扬
            long praise = appraiseTreeNode.isPraise() ? 1 : -1;
            operations.increment("/praiseCount", praise);
            // 加分
            int scoreToPlus = ObjectUtils.isEmpty(appraiseTreeNode.getScore()) ? 0 : appraiseTreeNode.getScore();
            operations.increment("/score", scoreToPlus);
            // patch doc
            appraiseRecordRepository.save(record.getId(), PK.buildOf(PK.PK_APPRAISE_RECORD, schoolId), AppraiseRecord.class, operations);
        }
    }

    @Override
    public List<AppraiseRecordItem> findVoteRecord(FindVoteRecordDto findVoteRecordDto) {
        String periodId = findVoteRecordDto.getPeriodId();
        String targetId = StringUtils.isBlank(findVoteRecordDto.getTargetId()) ? null : findVoteRecordDto.getTargetId();
        String targetType = StringUtils.isBlank(findVoteRecordDto.getTargetType()) ? null : findVoteRecordDto.getTargetType();
        String classId = StringUtils.isBlank(findVoteRecordDto.getClassId()) ? null : findVoteRecordDto.getClassId();
        User loginUser = SecurityUtil.getLoginUser();
        String teacherId = loginUser.getId();
        String schoolId = loginUser.getSchoolId();

        List<School.Semester> semesters = schoolRepository.findSemestersById(schoolId, periodId);
        String academicYearId = SchoolDateUtil.generateAcademicId(semesters, LocalDate.now());
        List<AppraiseRecordItem> appraiseRecordItems = appraiseRecordRepository.searchNodesByCondition(
                targetId,
                targetType,
                classId,
                teacherId,
                academicYearId,
                String.format(PK.PK_APPRAISE_RECORD, schoolId)
        );
        return appraiseRecordItems;
    }

    @Override
    public void recallVote(RecallVoteDto recallVoteDto) {
        String recordId = recallVoteDto.getRecordId();
        String nodeId = recallVoteDto.getNodeId();
        User loginUser = SecurityUtil.getLoginUser();
        String schoolId = loginUser.getSchoolId();
        String userId = loginUser.getId();

        Optional<AppraiseRecord> optional = appraiseRecordRepository.findById(recordId, PK.buildOf(PK.PK_APPRAISE_RECORD, schoolId));
        AppraiseRecord appraiseRecord = optional.orElseThrow(() -> new ServiceException("该记录不存在"));
        AppraiseRecordItem record = appraiseRecord.getNodes()
                .stream()
                .filter(item -> nodeId.equals(item.getId()))
                .findFirst().orElseThrow(() -> new ServiceException("该记录节点不存在"));
        // 鉴权(不是创建老师不能撤回)
        if (!userId.equals(record.getCreatorId())) {
            throw  new ServiceException(ErrorCode.NO_AUTH_ERROR.getCode(), "您不是创建老师，不能撤回");
        }
        // 删除评价项并且恢复评分
        appraiseRecord.getNodes().removeIf(item -> nodeId.equals(item.getId()));
        boolean praise = record.getAppraiseNode().isPraise();
        Integer newPraiseCount = appraiseRecord.getPraiseCount() +  (praise ? -1 : 1);
        appraiseRecord.setPraiseCount(newPraiseCount);
        int score = record.getAppraiseNode().getScore() == null ? 0 : record.getAppraiseNode().getScore();
        Integer newScore = appraiseRecord.getScore() - score;
        appraiseRecord.setScore(newScore);
        // 保存
        appraiseRecordRepository.save(appraiseRecord);
    }

    /**
    * 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;
    }
}