package com.gunshi.project.ss.service;


import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.gunshi.project.ss.common.mapper.StFlowRMapper;
import com.gunshi.project.ss.common.model.StFlowR;
import com.gunshi.project.ss.common.model.StStbprpB;
import com.gunshi.project.ss.entity.dto.StFlowDataCheckDto;
import com.gunshi.project.ss.entity.vo.StFlowLowerDataCheckVo;
import com.gunshi.project.ss.entity.vo.StFlowRListVo;
import com.gunshi.project.ss.entity.vo.StFlowRVo;
import com.gunshi.project.ss.mapper.StFlowRVoMapper;
import jakarta.servlet.http.HttpServletResponse;
import lombok.extern.slf4j.Slf4j;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.io.IOException;
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.net.URLEncoder;
import java.time.Duration;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.time.temporal.ChronoUnit;
import java.util.*;

@Service
@Slf4j
@Transactional(rollbackFor = Exception.class)
public class StFlowRService extends ServiceImpl<StFlowRMapper, StFlowR> {

    @Autowired
    private StFlowRVoMapper voMapper;

    @Autowired
    private StStbprpBService stStbprpBService;

    public StFlowR getNewDataByStcd(String stcd) {
        LambdaQueryWrapper<StFlowR> queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.eq(StFlowR::getStcd, stcd);
        queryWrapper.orderByDesc(StFlowR::getTm);
        queryWrapper.last("limit 1");
        return baseMapper.selectOne(queryWrapper);
    }

    public List<StFlowR> listNewData() {
        return this.baseMapper.listNewData();
    }

    public List<String> getStcdList() {
        return voMapper.listStcds();
    }

    public List<StFlowRVo> getDataByStcdAndTm(String stcd, Date tm) {
        return voMapper.getDataByStcdAndTm(stcd, tm);
    }

    public List<StFlowRListVo> listLatestData() {
        List<StFlowRListVo> res = new ArrayList<>();
        List<StStbprpB> flowStations = stStbprpBService.getFlowStations();
        LocalDateTime now = LocalDateTime.now();
        LocalDateTime lastDay = now.minusDays(1);

        for (StStbprpB flowStation : flowStations) {
            StFlowRListVo stFlowR = new StFlowRListVo();
            stFlowR.setStcd(flowStation.getStcd());
            stFlowR.setStnm(flowStation.getStnm());
            stFlowR.setLgtd(flowStation.getLgtd());
            stFlowR.setLttd(flowStation.getLttd());
            // 获取24小时内的所有流量数据
            List<StFlowR> list = lambdaQuery()
                    .eq(StFlowR::getStcd, flowStation.getStcd())
                    .ge(StFlowR::getTm, lastDay)
                    .le(StFlowR::getTm, now)
                    .orderByAsc(StFlowR::getTm) // 按时间升序排列，方便计算
                    .list();

            if(list.isEmpty()){
                res.add(stFlowR);
                continue;
            }

            // 设置最新时间点的数据
            StFlowR latestData = list.get(list.size() - 1);
            stFlowR.setTm(latestData.getTm());
            stFlowR.setQ(latestData.getQ());
            //判断状态
            LocalDateTime tm = latestData.getTm();
            Duration between = Duration.between(tm, now);
            if(between.toHours() > 24){
                stFlowR.setStatus(0);
            }else{
                stFlowR.setStatus(1);
            }
            // 计算统计值

            res.add(stFlowR);
        }
        return res;
    }


    public List<StFlowRListVo> upperDataCheck(StFlowDataCheckDto dto) {
        List<StFlowRListVo> res = new ArrayList<>();
        List<StFlowR> list = lambdaQuery()
                .eq(StFlowR::getStcd, dto.getStcd())
                .ge(StFlowR::getTm, dto.getDateTimeRangeSo().getStart())
                .le(StFlowR::getTm, dto.getDateTimeRangeSo().getEnd())
                .orderByAsc(StFlowR::getTm)
                .list();
        if(list.isEmpty()){
            return res;
        }

        for (StFlowR stFlowR : list) {
            StFlowRListVo stFlowRListVo = new StFlowRListVo();
            stFlowRListVo.setStcd(stFlowR.getStcd());
            stFlowRListVo.setQ(stFlowR.getQ());
            stFlowRListVo.setTm(stFlowR.getTm());
            res.add(stFlowRListVo);
        }

        // 3. 计算累计水量
        // 设置第一个时间点的累计水量为0
        res.get(0).setTotalWater(BigDecimal.ZERO);

        // 从第二个开始计算累计水量
        for (int i = 1; i < res.size(); i++) {
            StFlowRListVo current = res.get(i);
            StFlowRListVo previous = res.get(i - 1);

            // 计算时间间隔（秒）
            long seconds = ChronoUnit.SECONDS.between(previous.getTm(), current.getTm());
            // 使用前一个时间的流量计算水量
            BigDecimal previousFlow = previous.getQ();
            if (previousFlow == null) {
                previousFlow = BigDecimal.ZERO;
            }

            // 水量 = 流量 × 时间间隔（m³/s × s = m³，再除以10000转换为万m³）
            BigDecimal waterVolume = previousFlow
                    .multiply(BigDecimal.valueOf(seconds))  // m³
                    .divide(BigDecimal.valueOf(10000), 10, RoundingMode.HALF_UP); // 万m³

            // 累计水量 = 上一个累计水量 + 当前时段水量
            BigDecimal totalWater = previous.getTotalWater().add(waterVolume);

            current.setTotalWater(totalWater);
        }

        // 3. 将结果按时间降序排列（最新的时间在前面）
        res.sort(Comparator.comparing(StFlowRListVo::getTm).reversed());
        return res;
    }

    public StFlowLowerDataCheckVo lowerDataCheckVoR(StFlowDataCheckDto dto) {
        StFlowLowerDataCheckVo res = new StFlowLowerDataCheckVo();
        List<StFlowR> list = lambdaQuery()
                .eq(StFlowR::getStcd, dto.getStcd())
                .ge(StFlowR::getTm, dto.getDateTimeRangeSo().getStart())
                .le(StFlowR::getTm, dto.getDateTimeRangeSo().getEnd())
                .orderByAsc(StFlowR::getTm)
                .list();
        if(list.isEmpty()){
            return res;
        }
        // 1. 找出最大瞬时流量及其时间（此时res是按时间升序的）
        BigDecimal maxQ = list.get(0).getQ();
        LocalDateTime maxQTm = list.get(0).getTm();

        for (StFlowR vo : list) {
            if (vo.getQ() != null && vo.getQ().compareTo(maxQ) > 0) {
                maxQ = vo.getQ();
                maxQTm = vo.getTm();
            }
        }

        BigDecimal totalWater = BigDecimal.ZERO;

        // 2. 计算累计水量
        // 第一个时间点累计水量为0
        // 从第二个开始计算：上一个累计水量 + 流量 × 时间间隔
        for (int i = 1; i < list.size(); i++) {
            StFlowR current = list.get(i);
            StFlowR previous = list.get(i - 1);

            // 计算时间间隔（秒）
            long seconds = ChronoUnit.SECONDS.between(previous.getTm(), current.getTm());

            // 使用当前时间点的流量（矩形法）
            // 注意：这里使用的是上一个时间点的流量，不是当前时间点的
            // 也可以根据需求改为使用 current.getQ()
            BigDecimal previousFlow = previous.getQ() != null ? previous.getQ() : BigDecimal.ZERO;

            // 计算当前时段的水量：流量 × 时间间隔
            // 注意单位转换：流量 m³/s，时间 s，结果 m³，再转万m³
            BigDecimal waterVolume = previousFlow
                    .multiply(BigDecimal.valueOf(seconds))          // m³
                    .divide(BigDecimal.valueOf(10000), 10, RoundingMode.HALF_UP); // 万m³

            // 累加到总水量
            totalWater = totalWater.add(waterVolume);
        }
        // 3. 设置返回结果
        res.setMaxQ(maxQ);
        res.setMaxQTm(maxQTm);
        res.setTotalWater(totalWater);
        return res;
    }

    public List<StFlowR> getByStcd(StFlowDataCheckDto dto) {
        StStbprpB one = stStbprpBService.lambdaQuery()
                .eq(StStbprpB::getStcd, dto.getStcd()).one();
        if(one == null){
            throw new IllegalArgumentException("对不起，该站点不存在");
        }
        LambdaQueryWrapper<StFlowR> queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.eq(StFlowR::getStcd, dto.getStcd());
        queryWrapper.ge(StFlowR::getTm, dto.getDateTimeRangeSo().getStart());
        queryWrapper.le(StFlowR::getTm, dto.getDateTimeRangeSo().getEnd());
        queryWrapper.orderByDesc(StFlowR::getTm);
        List<StFlowR> stFlowRS = this.baseMapper.selectList(queryWrapper);
        stFlowRS.stream().forEach(o -> o.setStnm(one.getStnm()));
        return stFlowRS;
    }
    public void export(StFlowDataCheckDto dto, HttpServletResponse response) {
        // 1. 获取数据
        List<StFlowR> dataList = getByStcd(dto);

        // 2. 创建Excel工作簿
        try (Workbook workbook = new XSSFWorkbook()) {
            Sheet sheet = workbook.createSheet("流量数据");

            // 3. 创建标题行
            Row headerRow = sheet.createRow(0);
            headerRow.createCell(0).setCellValue("站点名称");
            headerRow.createCell(1).setCellValue("时间");
            headerRow.createCell(2).setCellValue("瞬时流量(m³/s)");

            // 4. 填充数据
            DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");

            for (int i = 0; i < dataList.size(); i++) {
                StFlowR flowData = dataList.get(i);
                Row row = sheet.createRow(i + 1);

                // 站点名称
                row.createCell(0).setCellValue(flowData.getStnm() != null ? flowData.getStnm() : "");

                // 时间
                String timeStr = "";
                if (flowData.getTm() != null) {
                    timeStr = flowData.getTm().format(formatter);
                }
                row.createCell(1).setCellValue(timeStr);

                // 流量
                if (flowData.getQ() != null) {
                    row.createCell(2).setCellValue(flowData.getQ().doubleValue());
                } else {
                    row.createCell(2).setCellValue("");
                }
            }

            // 5. 自动调整列宽
            for (int i = 0; i < 3; i++) {
                sheet.autoSizeColumn(i);
            }

            // 6. 设置响应头
            String fileName = "流量数据_" + System.currentTimeMillis() + ".xlsx";
            response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
            response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));

            // 7. 写入响应流
            workbook.write(response.getOutputStream());

        } catch (IOException e) {
            throw new RuntimeException("导出Excel失败", e);
        }
    }
}