package com.neotel.webbox.util;

import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.ExcelWriter;
import com.alibaba.excel.util.MapUtils;
import com.alibaba.excel.write.metadata.WriteSheet;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.neotel.webbox.capacity.box.Box;
import lombok.extern.slf4j.Slf4j;

import javax.servlet.http.HttpServletResponse;
import java.net.URLEncoder;
import java.util.List;
import java.util.Map;

@Slf4j
public class ExcelUtil {

    public static void downloadExcel(HttpServletResponse response){
        // 这里注意 有同学反应使用swagger 会导致各种问题，请直接用浏览器或者用postman
        try {
            response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
            response.setCharacterEncoding("utf-8");
            // 这里URLEncoder.encode可以防止中文乱码 当然和easyexcel没有关系
            String fileName = URLEncoder.encode("测试", "UTF-8").replaceAll("\\+", "%20");
            response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".xlsx");


            // 这里 需要指定写用哪个class去写
            try (ExcelWriter excelWriter = EasyExcel.write(fileName, Box.class).build()) {
                // 这里注意 如果同一个sheet只要创建一次
                WriteSheet writeSheet = EasyExcel.writerSheet("模板").registerWriteHandler(new I18nCellWriteHandler()).build();
                // 去调用写入,这里我调用了五次，实际使用时根据数据库分页的总的页数来
                for (int i = 0; i < 5; i++) {
                    // 分页去数据库查询数据 这里可以去数据库查询每一页的数据
                    //List<DemoData> data = data();
                    //excelWriter.write(data, writeSheet);
                }
            }
        } catch (Exception e) {
            log.error("下载Excel出错",e);
            // 重置response
            response.reset();
            response.setContentType("application/json");
            response.setCharacterEncoding("utf-8");
            Map<String, String> map = MapUtils.newHashMap();
            map.put("status", "failure");
            map.put("message", "下载文件失败" + e.getMessage());
            ObjectMapper objectMapper = new ObjectMapper();
            String resultStr = null;
            try {
                resultStr = objectMapper.writeValueAsString(map);
                response.getWriter().println(resultStr);
            } catch (Exception ex) {
                log.error("下载Excel时转换Json出错",ex);
            }
        }
    }
}