package cn.iocoder.yudao.module.mes.service.pd.price;

import cn.hutool.core.collection.CollUtil;
import cn.iocoder.yudao.module.mes.controller.admin.pd.price.vo.MesPdPriceCalcDetailRespVO;
import cn.iocoder.yudao.module.mes.controller.admin.pd.price.vo.MesPdPriceCalcReqVO;
import cn.iocoder.yudao.module.mes.controller.admin.pd.price.vo.MesPdPriceCalcRespVO;
import cn.iocoder.yudao.module.mes.dal.dataobject.pd.basedata.MesPdDiscountPolicyDO;
import cn.iocoder.yudao.module.mes.dal.dataobject.pd.basedata.MesPdServicePackageDO;
import cn.iocoder.yudao.module.mes.dal.dataobject.pd.basedata.MesPdTieredPriceDO;
import cn.iocoder.yudao.module.mes.dal.dataobject.pd.basedata.MesPdVoltageLevelDO;
import cn.iocoder.yudao.module.mes.dal.mysql.pd.basedata.MesPdDiscountPolicyMapper;
import cn.iocoder.yudao.module.mes.dal.mysql.pd.basedata.MesPdTieredPriceMapper;
import cn.iocoder.yudao.module.mes.service.pd.basedata.MesPdServicePackageService;
import cn.iocoder.yudao.module.mes.service.pd.basedata.MesPdVoltageLevelService;
import jakarta.annotation.Resource;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.validation.annotation.Validated;

import java.math.BigDecimal;
import java.time.LocalDateTime;
import java.util.ArrayList;
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.mes.enums.ErrorCodeConstants.PD_PRICE_CALC_OBJECT_NOT_CONFIGURED;

/**
 * MES 阶梯电价测算 Service 实现类
 *
 * @author 超级管理员
 */
@Service
@Validated
@Slf4j
public class MesPdPriceServiceImpl implements MesPdPriceService {

    private static final Integer CALC_TYPE_PACKAGE = 1;
    private static final Integer CALC_TYPE_VOLTAGE = 2;

    @Resource
    private MesPdTieredPriceMapper tieredPriceMapper;

    @Resource
    private MesPdDiscountPolicyMapper discountPolicyMapper;

    @Resource
    private MesPdServicePackageService servicePackageService;

    @Resource
    private MesPdVoltageLevelService voltageLevelService;

    @Override
    public MesPdPriceCalcRespVO calcPrice(MesPdPriceCalcReqVO reqVO) {
        // 1. 定位阶梯电价档位
        List<MesPdTieredPriceDO> tiers = getTieredPrices(reqVO);
        if (CollUtil.isEmpty(tiers)) {
            throw exception(PD_PRICE_CALC_OBJECT_NOT_CONFIGURED);
        }
        // 2. 分档累计计算原价
        BigDecimal quantity = reqVO.getQuantity();
        BigDecimal originalPrice = BigDecimal.ZERO;
        List<MesPdPriceCalcDetailRespVO> details = new ArrayList<>();
        for (MesPdTieredPriceDO tier : tiers) {
            BigDecimal lower = tier.getStartValue();
            BigDecimal upper = tier.getEndValue();
            if (quantity.compareTo(lower) <= 0) {
                break;
            }
            BigDecimal upperBound = upper == null ? quantity : upper.min(quantity);
            BigDecimal tierQuantity = upperBound.subtract(lower);
            if (tierQuantity.signum() <= 0) {
                continue;
            }
            BigDecimal subtotal = tier.getPricePerUnit().multiply(tierQuantity);
            originalPrice = originalPrice.add(subtotal);
            MesPdPriceCalcDetailRespVO detail = new MesPdPriceCalcDetailRespVO();
            detail.setStartValue(lower);
            detail.setEndValue(upper);
            detail.setTierQuantity(tierQuantity);
            detail.setPricePerUnit(tier.getPricePerUnit());
            detail.setSubtotal(subtotal);
            details.add(detail);
            if (upper != null && quantity.compareTo(upper) <= 0) {
                break;
            }
        }
        // 3. 叠加优惠策略（目标专属 + 全局，取最优）
        BigDecimal finalPrice = originalPrice;
        Integer targetType = Objects.equals(CALC_TYPE_PACKAGE, reqVO.getCalcType()) ? 1 : 2;
        Long targetId = Objects.equals(CALC_TYPE_PACKAGE, reqVO.getCalcType()) ? reqVO.getPackageId() : reqVO.getVoltageLevelId();
        List<MesPdDiscountPolicyDO> policies = discountPolicyMapper.selectListByTarget(targetType, targetId);
        LocalDateTime now = LocalDateTime.now();
        for (MesPdDiscountPolicyDO policy : policies) {
            if (policy.getStartDate() != null && now.isBefore(policy.getStartDate())) {
                continue;
            }
            if (policy.getEndDate() != null && now.isAfter(policy.getEndDate())) {
                continue;
            }
            if (policy.getPolicyValue() == null) {
                continue;
            }
            BigDecimal candidate;
            if (Objects.equals(policy.getPolicyType(), 1)) { // 折扣
                candidate = originalPrice.multiply(policy.getPolicyValue());
            } else { // 立减
                candidate = originalPrice.subtract(policy.getPolicyValue()).max(BigDecimal.ZERO);
            }
            finalPrice = finalPrice.min(candidate);
        }
        // 4. 组装返回
        MesPdPriceCalcRespVO respVO = new MesPdPriceCalcRespVO();
        respVO.setOriginalPrice(originalPrice);
        respVO.setFinalPrice(finalPrice);
        respVO.setDiscountAmount(originalPrice.subtract(finalPrice));
        respVO.setDetails(details);
        if (reqVO.getPackageId() != null) {
            MesPdServicePackageDO pkg = servicePackageService.validateServicePackageExists(reqVO.getPackageId());
            respVO.setPackageName(pkg.getName());
        }
        if (reqVO.getVoltageLevelId() != null) {
            MesPdVoltageLevelDO level = voltageLevelService.validateVoltageLevelExists(reqVO.getVoltageLevelId());
            respVO.setVoltageLevelName(level.getName());
        }
        return respVO;
    }

    private List<MesPdTieredPriceDO> getTieredPrices(MesPdPriceCalcReqVO reqVO) {
        if (Objects.equals(CALC_TYPE_PACKAGE, reqVO.getCalcType()) && reqVO.getPackageId() != null) {
            return tieredPriceMapper.selectListByPackageId(reqVO.getPackageId());
        }
        if (Objects.equals(CALC_TYPE_VOLTAGE, reqVO.getCalcType()) && reqVO.getVoltageLevelId() != null) {
            return tieredPriceMapper.selectListByVoltageLevelId(reqVO.getVoltageLevelId());
        }
        return null;
    }

}