package com.mes.device.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.mes.device.entity.EngineeringSequence;
import com.mes.device.mapper.EngineeringSequenceMapper;
import com.mes.device.service.EngineeringSequenceService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.dao.DuplicateKeyException;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.time.LocalDate;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
import java.util.Date;

/**
 * 工程序号信息服务实现类
 * 
 * @author mes
 * @since 2024-11-20
 */
@Slf4j
@Service
public class EngineeringSequenceServiceImpl extends ServiceImpl<EngineeringSequenceMapper, EngineeringSequence> implements EngineeringSequenceService {

    // 日期格式化器（线程不安全，使用ThreadLocal保证线程安全）
    private static final DateTimeFormatter DATE_FORMATTER = DateTimeFormatter.ofPattern("yyMMdd");

    @Override
    @Transactional(rollbackFor = Exception.class)
    public String generateAndSaveEngineeringId(Date date) {
        // 乐观重试，防止并发写入造成重复键
        int retry = 0;
        final int maxRetry = 5;
        while (true) {
            try {
                // 1. 查询当天最大序号，并加行锁避免并发重复
                Integer maxSequence = baseMapper.selectMaxSequenceByDateForUpdate(date);
                if (maxSequence == null) {
                    maxSequence = 0;
                }

                // 2. 序号自增1
                int newSequence = maxSequence + 1;

                // 3. 生成工程号：P + yyMMdd + 两位序号
                LocalDate localDate = date.toInstant().atZone(ZoneId.systemDefault()).toLocalDate();
                String dateStr = localDate.format(DATE_FORMATTER);
                String engineeringId = "P" + dateStr + String.format("%02d", newSequence);

                // 4. 保存到数据库
                EngineeringSequence engineeringSequence = new EngineeringSequence();
                engineeringSequence.setEngineeringId(engineeringId);
                engineeringSequence.setDate(date);
                engineeringSequence.setSequence(newSequence);
                engineeringSequence.setCreatedTime(new Date());
                engineeringSequence.setUpdatedTime(new Date());
                engineeringSequence.setCreatedBy("system");
                engineeringSequence.setUpdatedBy("system");

                save(engineeringSequence);

                log.info("生成工程号成功: engineeringId={}, date={}, sequence={}", engineeringId, date, newSequence);
                return engineeringId;

            } catch (DuplicateKeyException dup) {
                // 并发导致的唯一键冲突，重试
                if (++retry > maxRetry) {
                    log.error("生成工程号重试超过上限, date={}", date, dup);
                    throw new RuntimeException("生成工程号失败", dup);
                }
                log.warn("工程号生成发生并发冲突，准备重试，第{}次，date={}", retry, date);
            } catch (Exception e) {
                log.error("生成工程号失败, date={}", date, e);
                throw new RuntimeException("生成工程号失败", e);
            }
        }
    }
}