package com.gunshi.project.ss.service;


import cn.hutool.poi.excel.ExcelUtil;
import cn.hutool.poi.excel.ExcelWriter;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.gunshi.project.ss.mapper.StEvpoMapper;
import com.gunshi.project.ss.model.StEvpo;
import jakarta.servlet.http.HttpServletResponse;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.io.IOException;
import java.net.URLEncoder;
import java.util.List;

@Service
@Slf4j
@Transactional(rollbackFor = Exception.class)
public class StEvpoService extends ServiceImpl<StEvpoMapper, StEvpo> {
    public void export(HttpServletResponse response) {
        List<StEvpo> list = this.lambdaQuery().orderByAsc(StEvpo::getMonth).list();
        list.stream().forEach(o ->{
            o.setEvaporation(o.getEvaporation().setScale(2));
        });
        // 通过工具类创建writer
        ExcelWriter writer = ExcelUtil.getWriter();

        // 自定义标题别名（只包含需要导出的字段）
        writer.addHeaderAlias("month", "月份");
        writer.addHeaderAlias("evaporation", "日蒸发量(万m³)");

        // 只写出设置了别名的字段，默认写出所有字段
        writer.setOnlyAlias(true);

        // 一次性写出内容，使用默认样式
        writer.write(list, true);

        // 设置响应内容类型
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8");

        try {
            // 设置响应头信息
            String fileName = URLEncoder.encode("蒸发量数据", "UTF-8");
            response.setHeader("Content-Disposition", "attachment;filename=" + fileName + ".xlsx");

            // 将writer对象刷新到响应输出流中
            writer.flush(response.getOutputStream(), true);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 关闭writer，释放内存
            writer.close();
        }
    }
}