package cn.iocoder.yudao.module.research.service.fund;

import cn.hutool.core.collection.CollUtil;
import cn.iocoder.yudao.framework.common.util.object.BeanUtils;
import cn.iocoder.yudao.module.research.controller.admin.fund.vo.ResearchFundRecordSaveReqVO;
import cn.iocoder.yudao.module.research.dal.dataobject.application.ResearchApplicationDO;
import cn.iocoder.yudao.module.research.dal.dataobject.fund.ResearchFundRecordDO;
import cn.iocoder.yudao.module.research.dal.mysql.application.ResearchApplicationMapper;
import cn.iocoder.yudao.module.research.dal.mysql.fund.ResearchFundRecordMapper;
import cn.iocoder.yudao.module.research.enums.ResearchApplicationStatusEnum;
import cn.iocoder.yudao.module.research.enums.ResearchFundStatusEnum;
import cn.iocoder.yudao.module.system.api.storage.StorageAttachmentApi;
import jakarta.annotation.Resource;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.validation.annotation.Validated;

import java.math.BigDecimal;
import java.util.List;
import java.util.Objects;

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

/**
 * 经费拨付记录 Service 实现类
 *
 * 一期只在本模块内落地拨款记录（批次/金额/日期/收款方/凭证附件），不与财务模块同步；
 * 累计拨付金额以申报单 budget_amount（申请预算）为上限。
 */
@Service
@Validated
@Slf4j
public class ResearchFundRecordServiceImpl implements ResearchFundRecordService {

    public static final String FUND_RECORD_TYPE = "research_fund_record";

    @Resource
    private ResearchFundRecordMapper fundRecordMapper;

    @Resource
    private ResearchApplicationMapper applicationMapper;

    @Resource
    private StorageAttachmentApi storageAttachmentApi;

    @Override
    @Transactional(rollbackFor = Exception.class)
    public Long createFundRecord(ResearchFundRecordSaveReqVO createReqVO) {
        ResearchApplicationDO application = validateApplicationApproved(createReqVO.getApplicationId());
        validateVoucherRequired(createReqVO);

        // 累计校验：新登记金额 + 该申报单已有记录金额，不得超过申请预算
        BigDecimal registered = sumAmount(fundRecordMapper.selectListByApplicationId(application.getId()), null);
        validateAmountNotExceeded(createReqVO.getAmount(), registered, application.getBudgetAmount());

        ResearchFundRecordDO fundRecord = BeanUtils.toBean(createReqVO, ResearchFundRecordDO.class,
                in -> in.setId(null));
        fundRecordMapper.insert(fundRecord);

        storageAttachmentApi.bindAttachments("file", FUND_RECORD_TYPE,
                fundRecord.getId(), createReqVO.getBlobIds());
        return fundRecord.getId();
    }

    @Override
    @Transactional(rollbackFor = Exception.class)
    public void updateFundRecord(ResearchFundRecordSaveReqVO updateReqVO) {
        ResearchFundRecordDO exist = validateFundRecordExists(updateReqVO.getId());
        if (!ResearchFundStatusEnum.PENDING.getStatus().equals(exist.getStatus())) {
            throw exception(FUND_UPDATE_FAIL_STATUS,
                    exist.getId(), ResearchFundStatusEnum.nameOf(exist.getStatus()));
        }
        // 记录归属申报单不可变更，防止把拨款挪到别的课题下
        ResearchApplicationDO application = validateApplicationApproved(exist.getApplicationId());
        validateVoucherRequired(updateReqVO);

        BigDecimal registered = sumAmount(fundRecordMapper.selectListByApplicationId(exist.getApplicationId()),
                exist.getId());
        validateAmountNotExceeded(updateReqVO.getAmount(), registered, application.getBudgetAmount());

        ResearchFundRecordDO updateObj = BeanUtils.toBean(updateReqVO, ResearchFundRecordDO.class);
        updateObj.setApplicationId(exist.getApplicationId());
        fundRecordMapper.updateById(updateObj);

        storageAttachmentApi.updateAttachments("file", FUND_RECORD_TYPE,
                updateReqVO.getId(), updateReqVO.getBlobIds());
    }

    @Override
    @Transactional(rollbackFor = Exception.class)
    public void deleteFundRecord(Long id) {
        ResearchFundRecordDO exist = validateFundRecordExists(id);
        if (!ResearchFundStatusEnum.PENDING.getStatus().equals(exist.getStatus())) {
            throw exception(FUND_DELETE_FAIL_STATUS,
                    exist.getId(), ResearchFundStatusEnum.nameOf(exist.getStatus()));
        }

        fundRecordMapper.deleteById(id);
        storageAttachmentApi.deleteAttachmentsByRecord(FUND_RECORD_TYPE, id);
    }

    @Override
    public List<ResearchFundRecordDO> getFundRecordListByApplicationId(Long applicationId) {
        return fundRecordMapper.selectListByApplicationId(applicationId);
    }

    // =================== 内部方法 ===================

    private ResearchFundRecordDO validateFundRecordExists(Long id) {
        ResearchFundRecordDO fundRecord = fundRecordMapper.selectById(id);
        if (fundRecord == null) {
            throw exception(FUND_NOT_EXISTS);
        }
        return fundRecord;
    }

    /** 只有已立项的课题才能登记经费拨付 */
    private ResearchApplicationDO validateApplicationApproved(Long applicationId) {
        ResearchApplicationDO application = applicationMapper.selectById(applicationId);
        if (application == null) {
            throw exception(APPLICATION_NOT_EXISTS);
        }
        if (!ResearchApplicationStatusEnum.APPROVED.getStatus().equals(application.getStatus())) {
            throw exception(FUND_RECORD_FAIL_STATUS, application.getNo(),
                    ResearchApplicationStatusEnum.nameOf(application.getStatus()));
        }
        return application;
    }

    /** 状态为「已拨付」时必须上传凭证附件 */
    private void validateVoucherRequired(ResearchFundRecordSaveReqVO reqVO) {
        if (ResearchFundStatusEnum.PAID.getStatus().equals(reqVO.getStatus())
                && CollUtil.isEmpty(reqVO.getBlobIds())) {
            throw exception(FUND_VOUCHER_REQUIRED);
        }
    }

    /** 累计浮出校验：本次 + 已登记（排除 excludeId 自身）不得超过申请预算 */
    private void validateAmountNotExceeded(BigDecimal amount, BigDecimal registered, BigDecimal budget) {
        BigDecimal current = amount == null ? BigDecimal.ZERO : amount;
        BigDecimal total = registered.add(current);
        BigDecimal limit = budget == null ? BigDecimal.ZERO : budget;
        if (total.compareTo(limit) > 0) {
            throw exception(FUND_AMOUNT_EXCEEDED,
                    current.toPlainString(), registered.toPlainString(),
                    total.toPlainString(), limit.toPlainString());
        }
    }

    private BigDecimal sumAmount(List<ResearchFundRecordDO> list, Long excludeId) {
        if (CollUtil.isEmpty(list)) {
            return BigDecimal.ZERO;
        }
        return list.stream()
                .filter(item -> !Objects.equals(item.getId(), excludeId))
                .map(item -> item.getAmount() == null ? BigDecimal.ZERO : item.getAmount())
                .reduce(BigDecimal.ZERO, BigDecimal::add);
    }

}