package cn.iocoder.yudao.module.finance.service.subject;

import cn.iocoder.yudao.framework.common.pojo.PageResult;
import cn.iocoder.yudao.framework.common.util.object.BeanUtils;
import cn.iocoder.yudao.module.finance.controller.admin.subject.vo.FinAccountSubjectPageReqVO;
import cn.iocoder.yudao.module.finance.controller.admin.subject.vo.FinAccountSubjectSaveReqVO;
import cn.iocoder.yudao.module.finance.dal.dataobject.subject.FinAccountSubjectDO;
import cn.iocoder.yudao.module.finance.dal.mysql.subject.FinAccountSubjectMapper;
import cn.iocoder.yudao.module.finance.dal.mysql.voucher.FinVoucherEntryMapper;
import jakarta.annotation.Resource;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.validation.annotation.Validated;

import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Objects;
import java.util.Set;

import static cn.iocoder.yudao.framework.common.exception.util.ServiceExceptionUtil.exception;
import static cn.iocoder.yudao.module.finance.enums.ErrorCodeConstants.*;

/**
 * 会计科目 Service 实现类
 *
 * @author 超级管理员
 */
@Service
@Validated
public class FinAccountSubjectServiceImpl implements FinAccountSubjectService {

    @Resource
    private FinAccountSubjectMapper accountSubjectMapper;
    @Resource
    private FinVoucherEntryMapper voucherEntryMapper;

    @Override
    public Long createAccountSubject(FinAccountSubjectSaveReqVO createReqVO) {
        // 1. 校验科目编码唯一
        validateSubjectCodeUnique(null, createReqVO.getSubjectCode());
        // 2. 校验上级科目
        validateParent(createReqVO.getParentId(), null);
        // 3. 插入
        FinAccountSubjectDO subject = BeanUtils.toBean(createReqVO, FinAccountSubjectDO.class);
        accountSubjectMapper.insert(subject);
        return subject.getId();
    }

    @Override
    public void updateAccountSubject(FinAccountSubjectSaveReqVO updateReqVO) {
        // 1. 校验存在
        validateAccountSubjectExists(updateReqVO.getId());
        // 2. 校验科目编码唯一
        validateSubjectCodeUnique(updateReqVO.getId(), updateReqVO.getSubjectCode());
        // 3. 校验上级科目（不能选自己，也不能选自己的下级）
        validateParent(updateReqVO.getParentId(), updateReqVO.getId());
        // 4. 更新
        accountSubjectMapper.updateById(BeanUtils.toBean(updateReqVO, FinAccountSubjectDO.class));
    }

    @Override
    public void deleteAccountSubject(Long id) {
        FinAccountSubjectDO subject = validateAccountSubjectExists(id);
        // 1. 校验是否存在下级科目
        List<FinAccountSubjectDO> children = accountSubjectMapper.selectListByParentId(id);
        if (!children.isEmpty()) {
            throw exception(ACCOUNT_SUBJECT_HAS_CHILDREN, subject.getSubjectName(), children.size());
        }
        // 2. 校验是否被凭证分录引用
        Long referencedCount = voucherEntryMapper.selectCountBySubjectCodes(List.of(subject.getSubjectCode()));
        if (referencedCount != null && referencedCount > 0) {
            throw exception(ACCOUNT_SUBJECT_REFERENCED, subject.getSubjectName(), referencedCount);
        }
        // 3. 删除
        accountSubjectMapper.deleteById(id);
    }

    @Override
    @Transactional(rollbackFor = Exception.class)
    public void deleteAccountSubjectList(List<Long> ids) {
        ids.forEach(this::deleteAccountSubject);
    }

    private FinAccountSubjectDO validateAccountSubjectExists(Long id) {
        FinAccountSubjectDO subject = accountSubjectMapper.selectById(id);
        if (subject == null) {
            throw exception(ACCOUNT_SUBJECT_NOT_EXISTS);
        }
        return subject;
    }

    private void validateSubjectCodeUnique(Long id, String subjectCode) {
        FinAccountSubjectDO subject = accountSubjectMapper.selectBySubjectCode(subjectCode);
        if (subject == null) {
            return;
        }
        if (id == null || !Objects.equals(subject.getId(), id)) {
            throw exception(ACCOUNT_SUBJECT_CODE_DUPLICATE, subjectCode);
        }
    }

    /**
     * 校验上级科目：非空时必须存在，且不能是自己或自己的下级（避免形成环）
     *
     * @param parentId 上级科目编号
     * @param selfId   当前科目编号；新增时传 null
     */
    private void validateParent(Long parentId, Long selfId) {
        if (parentId == null) {
            return;
        }
        if (Objects.equals(parentId, selfId)) {
            throw exception(ACCOUNT_SUBJECT_PARENT_SELF);
        }
        FinAccountSubjectDO parent = accountSubjectMapper.selectById(parentId);
        if (parent == null) {
            throw exception(ACCOUNT_SUBJECT_PARENT_NOT_EXISTS, parentId);
        }
        // 自下而上回溯，若遇到自己，说明选择的上级是自己的下级
        Set<Long> visited = new HashSet<>();
        Long cursor = parentId;
        while (cursor != null && visited.add(cursor)) {
            if (Objects.equals(cursor, selfId)) {
                throw exception(ACCOUNT_SUBJECT_PARENT_CYCLE, parent.getSubjectName());
            }
            FinAccountSubjectDO node = accountSubjectMapper.selectById(cursor);
            cursor = node == null ? null : node.getParentId();
        }
    }

    @Override
    public FinAccountSubjectDO getAccountSubject(Long id) {
        return accountSubjectMapper.selectById(id);
    }

    @Override
    public PageResult<FinAccountSubjectDO> getAccountSubjectPage(FinAccountSubjectPageReqVO pageReqVO) {
        return accountSubjectMapper.selectPage(pageReqVO);
    }

    @Override
    public List<FinAccountSubjectDO> getAccountSubjectList() {
        return accountSubjectMapper.selectListAll();
    }

    @Override
    public FinAccountSubjectDO getAccountSubjectByCode(String subjectCode) {
        return accountSubjectMapper.selectBySubjectCode(subjectCode);
    }

    @Override
    public List<FinAccountSubjectDO> getAccountSubjectListByCodes(Collection<String> subjectCodes) {
        return accountSubjectMapper.selectListBySubjectCodes(subjectCodes);
    }

}