package com.ruoyi.sales.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.toolkit.CollectionUtils;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.ruoyi.basic.mapper.CustomerMapper;
import com.ruoyi.basic.pojo.Customer;
import com.ruoyi.common.exception.base.BaseException;
import com.ruoyi.sales.dto.SalesLedgerDto;
import com.ruoyi.sales.mapper.SalesLedgerMapper;
import com.ruoyi.sales.mapper.SalesLedgerProductMapper;
import com.ruoyi.sales.pojo.SalesLedger;
import com.ruoyi.sales.pojo.SalesLedgerProduct;
import com.ruoyi.sales.service.ISalesLedgerService;
import lombok.AllArgsConstructor;
import org.springframework.beans.BeanUtils;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.*;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;

/**
 * 销售台账Service业务层处理
 *
 * @author ruoyi
 * @date 2025-05-08
 */
@Service
@AllArgsConstructor
public class SalesLedgerServiceImpl extends ServiceImpl<SalesLedgerMapper, SalesLedger> implements ISalesLedgerService {

    private SalesLedgerMapper salesLedgerMapper;

    private CustomerMapper customerMapper;

    private SalesLedgerProductMapper salesLedgerProductMapper;

    private static final String LOCK_PREFIX = "contract_no_lock:";
    private static final long LOCK_WAIT_TIMEOUT = 10; // 锁等待超时时间（秒）
    private static final long LOCK_EXPIRE_TIME = 30;  // 锁自动过期时间（秒）

    private final RedisTemplate<String, String> redisTemplate;

    @Override
    public List<SalesLedger> selectSalesLedgerList(SalesLedger salesLedger) {
        return salesLedgerMapper.selectList(new LambdaQueryWrapper<>());
    }

    public List<SalesLedgerDto> getSalesLedgerWithProducts() {
        List<SalesLedger> ledgers = salesLedgerMapper.selectList(new LambdaQueryWrapper<>());
        List<SalesLedgerProduct> products = salesLedgerProductMapper.selectList(new LambdaQueryWrapper<>());

        Map<Long, List<SalesLedgerProduct>> productMap = products.stream()
                .collect(Collectors.groupingBy(SalesLedgerProduct::getSalesLedgerId));

        return ledgers.stream().map(ledger -> {
            SalesLedgerDto dto = new SalesLedgerDto();
            org.springframework.beans.BeanUtils.copyProperties(ledger, dto);

            List<SalesLedgerProduct> ledgerProducts = productMap.getOrDefault(ledger.getId(), Collections.emptyList());
            if (!ledgerProducts.isEmpty()) {
                dto.setHasChildren(true);
                dto.setProductData(ledgerProducts);
            }
            return dto;
        }).collect(Collectors.toList());
    }

    @Override
    public SalesLedger selectSalesLedgerById(Long id) {
        return salesLedgerMapper.selectById(id);
    }

    @Override
    @Transactional(rollbackFor = Exception.class)
    public int deleteSalesLedgerByIds(Long[] ids) {
        List<Long> idList = Arrays.stream(ids)
                .filter(Objects::nonNull)
                .collect(Collectors.toList());

        if (CollectionUtils.isEmpty(idList)) {
            return 0;
        }
        // 1. 先删除子表数据
        LambdaQueryWrapper<SalesLedgerProduct> productWrapper = new LambdaQueryWrapper<>();
        productWrapper.in(SalesLedgerProduct::getSalesLedgerId, idList);
        salesLedgerProductMapper.delete(productWrapper);

        // 2. 再删除主表数据
        return salesLedgerMapper.deleteBatchIds(idList);
    }

    @Transactional(rollbackFor = Exception.class)
    public int addOrUpdateSalesLedger(SalesLedgerDto salesLedgerDto) {
        // 1. 校验客户信息
        Customer customer = customerMapper.selectById(salesLedgerDto.getCustomerId());
        if (customer == null) {
            throw new BaseException("客户不存在");
        }

        // 2. DTO转Entity
        SalesLedger salesLedger = convertToEntity(salesLedgerDto);
        salesLedger.setCustomerName(customer.getCustomerName());
        salesLedger.setTenantId(customer.getTenantId());

        // 3. 新增或更新主表
        if (salesLedger.getId() == null) {
            // 生成合同编号
            String contractNo = generateSalesContractNo();
            salesLedger.setSalesContractNo(contractNo);
            salesLedgerMapper.insert(salesLedger);
        } else {
            salesLedgerMapper.updateById(salesLedger);
        }

        // 4. 处理子表数据
        if (salesLedgerDto.getProductData() != null && !salesLedgerDto.getProductData().isEmpty()) {
            handleSalesLedgerProducts(salesLedger.getId(), salesLedgerDto.getProductData());
        }

        return 1; // 操作成功返回1
    }

    private void handleSalesLedgerProducts(Long salesLedgerId, List<SalesLedgerProduct> products) {
        // 按ID分组，区分新增和更新的记录
        Map<Boolean, List<SalesLedgerProduct>> partitionedProducts = products.stream()
                .peek(p -> p.setSalesLedgerId(salesLedgerId))
                .collect(Collectors.partitioningBy(p -> p.getId() != null));

        List<SalesLedgerProduct> updateList = partitionedProducts.get(true);
        List<SalesLedgerProduct> insertList = partitionedProducts.get(false);

        // 执行更新操作
        if (!updateList.isEmpty()) {
            salesLedgerProductMapper.updateBatchSomeColumn(updateList);
        }
        // 执行插入操作
        if (!insertList.isEmpty()) {
            salesLedgerProductMapper.insertBatchSomeColumn(insertList);
        }
    }

    private SalesLedger convertToEntity(SalesLedgerDto dto) {
        SalesLedger entity = new SalesLedger();
        BeanUtils.copyProperties(dto, entity);
        return entity;
    }

    @Transactional(readOnly = true)
    public String generateSalesContractNo() {
        LocalDate currentDate = LocalDate.now();
        String datePart = currentDate.format(DateTimeFormatter.BASIC_ISO_DATE);
        String lockKey = LOCK_PREFIX + datePart;
        String lockValue = Thread.currentThread().getId() + "-" + System.nanoTime(); // 唯一标识锁持有者

        try {
            // 1. 尝试获取分布式锁（循环直到超时）
            long startWaitTime = System.currentTimeMillis();
            while (System.currentTimeMillis() - startWaitTime < LOCK_WAIT_TIMEOUT * 1000) {
                // SET key value NX PX 30000：仅当锁不存在时获取，设置30秒过期
                Boolean locked = redisTemplate.opsForValue().setIfAbsent(lockKey, lockValue, LOCK_EXPIRE_TIME, TimeUnit.SECONDS);
                if (Boolean.TRUE.equals(locked)) {
                    break; // 成功获取锁
                }
                // 短暂休眠避免忙等待
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    Thread.currentThread().interrupt();
                    throw new RuntimeException("获取锁时被中断", e);
                }
            }

            if (!redisTemplate.hasKey(lockKey)) {
                throw new RuntimeException("获取合同编号生成锁失败：超时");
            }

            // 2. 查询当天已存在的序列号（与原逻辑一致）
            List<Integer> existingSequences = salesLedgerMapper.selectSequencesByDate(datePart);
            int nextSequence = findFirstMissingSequence(existingSequences);

            return datePart + String.format("%02d", nextSequence);
        } finally {
            // 3. 释放锁（使用Lua脚本保证原子性，避免误删其他线程的锁）
            String luaScript = "if redis.call('GET', KEYS[1]) == ARGV[1] then return redis.call('DEL', KEYS[1]) else return 0 end";
            redisTemplate.execute(
                    new DefaultRedisScript<>(luaScript, Long.class),
                    Collections.singletonList(lockKey),
                    lockValue // 只有持有相同值的线程才能删除锁
            );
        }
    }

    private int findFirstMissingSequence(List<Integer> sequences) {
        if (sequences.isEmpty()) {
            return 1;
        }
        // 排序后查找第一个缺失的正整数（与原逻辑一致）
        sequences.sort(Integer::compareTo);
        int next = 1;
        for (int seq : sequences) {
            if (seq == next) {
                next++;
            } else if (seq > next) {
                break;
            }
        }
        return next;
    }
}