package com.ruoyi.report.service.impl;

import cn.hutool.core.collection.CollectionUtil;
import cn.hutool.core.date.DateUtil;
import com.alibaba.excel.EasyExcel;
import com.ruoyi.framework.exception.ErrorException;
import com.ruoyi.report.dto.SpcChartDto;
import com.ruoyi.report.mapper.SpcChartMapper;
import com.ruoyi.report.service.SpcChartService;
import com.ruoyi.report.vo.SpcResultVo;
import lombok.AllArgsConstructor;
import org.springframework.stereotype.Service;

import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.math.BigDecimal;
import java.math.MathContext;
import java.math.RoundingMode;
import java.util.*;
import java.util.stream.Collectors;

/**
 * SPC控制图服务实现
 */
@Service
@AllArgsConstructor
public class SpcChartServiceImpl implements SpcChartService {

    private SpcChartMapper spcChartMapper;

    @Override
    public SpcResultVo analyze(SpcChartDto dto) {
        // 查询数据
        List<Map<String, Object>> itemData = spcChartMapper.getItemData(dto);

        if (CollectionUtil.isEmpty(itemData)) {
            return null;
        }

        // 获取数值列表
        List<BigDecimal> values = itemData.stream()
                .map(m -> new BigDecimal((String) m.get("lastValue")))
                .collect(Collectors.toList());

        // 子组大小，默认为5
        int subgroupSize = dto.getSubgroupSize() != null ? dto.getSubgroupSize() : 5;

        // 分组
        List<List<BigDecimal>> subgroups = new ArrayList<>();
        for (int i = 0; i < values.size(); i += subgroupSize) {
            int end = Math.min(i + subgroupSize, values.size());
            if (end - i >= 2) { // 至少需要2个数据点
                subgroups.add(values.subList(i, end));
            }
        }

        if (subgroups.isEmpty()) {
            throw new ErrorException("数据不足以进行SPC分析");
        }

        // 计算X-bar和R
        List<BigDecimal> xBarData = new ArrayList<>();
        List<BigDecimal> rData = new ArrayList<>();
        List<String> sampleLabels = new ArrayList<>();

        for (int i = 0; i < subgroups.size(); i++) {
            List<BigDecimal> subgroup = subgroups.get(i);
            BigDecimal sum = subgroup.stream().reduce(BigDecimal.ZERO, BigDecimal::add);
            BigDecimal mean = sum.divide(new BigDecimal(subgroup.size()), 10, RoundingMode.HALF_UP);
            BigDecimal max = subgroup.stream().max(BigDecimal::compareTo).orElse(BigDecimal.ZERO);
            BigDecimal min = subgroup.stream().min(BigDecimal::compareTo).orElse(BigDecimal.ZERO);
            BigDecimal range = max.subtract(min);

            xBarData.add(mean.setScale(4, RoundingMode.HALF_UP));
            rData.add(range.setScale(4, RoundingMode.HALF_UP));
            sampleLabels.add("组" + (i + 1));
        }

        // 计算控制限
        BigDecimal xBarMean = xBarData.stream().reduce(BigDecimal.ZERO, BigDecimal::add)
                .divide(new BigDecimal(xBarData.size()), 10, RoundingMode.HALF_UP);
        BigDecimal rMean = rData.stream().reduce(BigDecimal.ZERO, BigDecimal::add)
                .divide(new BigDecimal(rData.size()), 10, RoundingMode.HALF_UP);

        // A2, D3, D4 常数 (针对子组大小)
        BigDecimal A2 = getA2(subgroupSize);
        BigDecimal D3 = getD3(subgroupSize);
        BigDecimal D4 = getD4(subgroupSize);

        // X-bar 控制限
        BigDecimal xBarUcl = dto.getUcl() != null ? dto.getUcl() :
                xBarMean.add(A2.multiply(rMean)).setScale(4, RoundingMode.HALF_UP);
        BigDecimal xBarLcl = dto.getLcl() != null ? dto.getLcl() :
                xBarMean.subtract(A2.multiply(rMean)).setScale(4, RoundingMode.HALF_UP);

        // R 控制限
        BigDecimal rUcl = D4.multiply(rMean).setScale(4, RoundingMode.HALF_UP);
        BigDecimal rLcl = D3.multiply(rMean).setScale(4, RoundingMode.HALF_UP);

        // 构建结果
        SpcResultVo result = new SpcResultVo();

        SpcResultVo.ChartData xBarChart = new SpcResultVo.ChartData();
        xBarChart.setData(xBarData);
        xBarChart.setUcl(xBarUcl);
        xBarChart.setLcl(xBarLcl);
        xBarChart.setCl(xBarMean.setScale(4, RoundingMode.HALF_UP));
        xBarChart.setSampleLabels(sampleLabels);
        result.setXBar(xBarChart);

        SpcResultVo.ChartData rChart = new SpcResultVo.ChartData();
        rChart.setData(rData);
        rChart.setUcl(rUcl);
        rChart.setLcl(rLcl);
        rChart.setCl(rMean.setScale(4, RoundingMode.HALF_UP));
        rChart.setSampleLabels(sampleLabels);
        result.setRChart(rChart);

        // 制程能力
        SpcResultVo.Capability capability = calculateCapability(values, dto.getUcl(), dto.getLcl());
        result.setCapability(capability);

        return result;
    }

    @Override
    public SpcResultVo.Capability getCapability(SpcChartDto dto) {
        List<Map<String, Object>> itemData = spcChartMapper.getItemData(dto);

        if (CollectionUtil.isEmpty(itemData)) {
            return null;
        }

        List<BigDecimal> values = itemData.stream()
                .map(m -> new BigDecimal((String) m.get("lastValue")))
                .collect(Collectors.toList());

        return calculateCapability(values, dto.getUcl(), dto.getLcl());
    }

    @Override
    public void export(SpcChartDto dto, HttpServletResponse response) {
        SpcResultVo result = analyze(dto);

        if (result == null) {
            return;
        }

        try {
            response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
            response.setCharacterEncoding("utf-8");
            String fileName = "SPC分析数据_" + DateUtil.format(new Date(), "yyyyMMddHHmmss");
            response.setHeader("Content-disposition", "attachment;filename=" + fileName + ".xlsx");

            // 构建导出数据
            List<Map<String, Object>> exportData = new ArrayList<>();
            List<String> labels = result.getXBar().getSampleLabels();
            List<BigDecimal> xBarData = result.getXBar().getData();
            List<BigDecimal> rData = result.getRChart().getData();

            for (int i = 0; i < labels.size(); i++) {
                Map<String, Object> row = new HashMap<>();
                row.put("sampleLabel", labels.get(i));
                row.put("xBar", xBarData.get(i));
                row.put("r", rData.get(i));
                exportData.add(row);
            }

            EasyExcel.write(response.getOutputStream())
                    .sheet("SPC分析数据")
                    .doWrite(exportData);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public List<String> getItemNames(SpcChartDto dto) {
        return spcChartMapper.getItemNames(dto);
    }

    @Override
    public List<String> getSampleNames(SpcChartDto dto) {
        return spcChartMapper.getSampleNames(dto);
    }

    /**
     * 计算制程能力
     */
    private SpcResultVo.Capability calculateCapability(List<BigDecimal> values, BigDecimal ucl, BigDecimal lcl) {
        if (ucl == null || lcl == null) {
            return null;
        }

        SpcResultVo.Capability capability = new SpcResultVo.Capability();

        // 计算均值和标准差
        BigDecimal sum = values.stream().reduce(BigDecimal.ZERO, BigDecimal::add);
        BigDecimal mean = sum.divide(new BigDecimal(values.size()), 10, RoundingMode.HALF_UP);

        BigDecimal variance = BigDecimal.ZERO;
        for (BigDecimal v : values) {
            BigDecimal diff = v.subtract(mean);
            variance = variance.add(diff.multiply(diff));
        }
        variance = variance.divide(new BigDecimal(values.size() - 1), 10, RoundingMode.HALF_UP);
        BigDecimal stdDev = sqrt(variance);

        // 计算Cp, Cpk
        BigDecimal USL = ucl;
        BigDecimal LSL = lcl;
        BigDecimal tolerance = USL.subtract(LSL);

        BigDecimal cp = tolerance.divide(stdDev.multiply(new BigDecimal(6)), 4, RoundingMode.HALF_UP);
        BigDecimal cpu = USL.subtract(mean).divide(stdDev.multiply(new BigDecimal(3)), 4, RoundingMode.HALF_UP);
        BigDecimal cpl = mean.subtract(LSL).divide(stdDev.multiply(new BigDecimal(3)), 4, RoundingMode.HALF_UP);
        BigDecimal cpk = cpu.min(cpl);

        capability.setCp(cp);
        capability.setCpk(cpk);
        capability.setPp(cp); // 简化处理
        capability.setPpk(cpk);

        return capability;
    }

    /**
     * 获取A2常数
     */
    private BigDecimal getA2(int n) {
        double[] a2Values = {0, 1.880, 1.023, 0.729, 0.577, 0.483, 0.419, 0.373, 0.337, 0.308};
        return new BigDecimal(a2Values[Math.min(n, 9)]);
    }

    /**
     * 获取D3常数
     */
    private BigDecimal getD3(int n) {
        double[] d3Values = {0, 0, 0, 0, 0, 0, 0.076, 0.136, 0.184, 0.223};
        return new BigDecimal(d3Values[Math.min(n, 9)]);
    }

    /**
     * 获取D4常数
     */
    private BigDecimal getD4(int n) {
        double[] d4Values = {0, 3.267, 2.574, 2.282, 2.114, 2.004, 1.924, 1.864, 1.816, 1.777};
        return new BigDecimal(d4Values[Math.min(n, 9)]);
    }

    /**
     * 平方根计算
     */
    private BigDecimal sqrt(BigDecimal value) {
        BigDecimal x = value;
        BigDecimal tolerance = new BigDecimal("1E-10");
        BigDecimal guess = value.divide(BigDecimal.valueOf(2), MathContext.DECIMAL128);

        while (x.subtract(guess).abs().compareTo(tolerance) > 0) {
            x = guess;
            guess = x.add(value.divide(x, MathContext.DECIMAL128)).divide(new BigDecimal("2"), MathContext.DECIMAL128);
        }

        return guess;
    }

}