package com.oms.service;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.oms.entity.PricingRule;
import com.oms.mapper.PricingRuleMapper;
import com.oms.dto.PricingRuleDTO;
import com.oms.enums.GenericStatus;
import lombok.RequiredArgsConstructor;
import org.springframework.stereotype.Service;
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.time.LocalDateTime;
import java.util.List;

@Service
@RequiredArgsConstructor
public class PricingRuleService {
    private final PricingRuleMapper mapper;

    public List<PricingRule> listRules(String ruleType, String status) {
        LambdaQueryWrapper<PricingRule> wrapper = new LambdaQueryWrapper<>();
        if (ruleType != null) wrapper.eq(PricingRule::getRuleType, ruleType);
        if (status != null) wrapper.eq(PricingRule::getStatus, status);
        wrapper.orderByDesc(PricingRule::getCreatedAt);
        return mapper.selectList(wrapper);
    }

    public PricingRule getRule(Long id) {
        return mapper.selectById(id);
    }

    public PricingRule createRule(PricingRuleDTO dto) {
        PricingRule rule = new PricingRule();
        rule.setRuleNo("PR" + System.currentTimeMillis());
        rule.setRuleName(dto.getRuleName());
        rule.setRuleType(dto.getRuleType());
        rule.setProductSkuId(dto.getProductSkuId());
        rule.setChannelId(dto.getChannelId());
        rule.setBasePrice(dto.getBasePrice());
        rule.setDiscountRate(dto.getDiscountRate());
        rule.setFixedPrice(dto.getFixedPrice());
        rule.setPriority(dto.getPriority());
        rule.setStatus(GenericStatus.ACTIVE.getCode());
        rule.setStartDate(dto.getStartDate());
        rule.setEndDate(dto.getEndDate());
        rule.setCreatedAt(LocalDateTime.now());
        mapper.insert(rule);
        return rule;
    }

    public PricingRule updateRule(Long id, PricingRuleDTO dto) {
        PricingRule rule = mapper.selectById(id);
        if (rule == null) return null;
        rule.setRuleName(dto.getRuleName());
        rule.setRuleType(dto.getRuleType());
        rule.setProductSkuId(dto.getProductSkuId());
        rule.setChannelId(dto.getChannelId());
        rule.setBasePrice(dto.getBasePrice());
        rule.setDiscountRate(dto.getDiscountRate());
        rule.setFixedPrice(dto.getFixedPrice());
        rule.setPriority(dto.getPriority());
        rule.setStartDate(dto.getStartDate());
        rule.setEndDate(dto.getEndDate());
        rule.setUpdatedAt(LocalDateTime.now());
        mapper.updateById(rule);
        return rule;
    }

    public void deleteRule(Long id) {
        mapper.deleteById(id);
    }

    public BigDecimal calculatePrice(Long skuId, String channelId, BigDecimal basePrice) {
        LambdaQueryWrapper<PricingRule> wrapper = new LambdaQueryWrapper<>();
        wrapper.eq(PricingRule::getProductSkuId, skuId.toString())
               .eq(PricingRule::getChannelId, channelId)
               .eq(PricingRule::getStatus, GenericStatus.ACTIVE.getCode());
        PricingRule rule = mapper.selectOne(wrapper);

        if (rule == null) return basePrice;

        // 校验规则有效期
        LocalDateTime now = LocalDateTime.now();
        if (rule.getStartDate() != null && now.isBefore(rule.getStartDate())) return basePrice;
        if (rule.getEndDate() != null && now.isAfter(rule.getEndDate())) return basePrice;

        if (rule.getFixedPrice() != null) {
            return rule.getFixedPrice();
        }
        if (rule.getDiscountRate() != null) {
            return basePrice.multiply(rule.getDiscountRate()).divide(BigDecimal.valueOf(100), 2, RoundingMode.HALF_UP);
        }
        return basePrice;
    }
}