/**
 * 算法检测器 JSON（单机图 / 风场总图）→ 前端与报告共用的面板结构。
 * 单机：通用 data[]，或多面板 panels[]。
 * 风场：chartType=series 曲线叠加，chartType=value 单值柱状对比。
 */
export const PO_TO_TEMPLATE_KEY = {
  anomalyPowercurvePO: "wind_power_curve",
  anomalyScatterPO: "wind_power_scatter",
  anomalyStaticyawPO: "yaw_static",
  anomalyCabletwistPO: "yaw_twist",
  anomalyYawErrorPO: "yaw_error",
  anomalyYawCountPO: "yaw_count",
  anomalyPitchcoordPO: "pitch_coord",
  anomalyPitchregulationPO: "pitch_regulation",
  anomalyMinpitchPO: "pitch_min",
  anomalyPowerqualityPO: "ctrl_power_quality",
  anomalyOperationPO: "ctrl_op_state",
  anomalyDeloadPO: "ctrl_deload",
  anomalyCpPO: "aero_cp",
  anomalyTsrPO: "aero_tsr",
  anomalyCpTsrPO: "aero_tsr_wind",
};

export const FARM_VALUE_AXIS = {
  yaw_error: "静态偏航误差 (°)",
  yaw_count: "偏航次数",
  pitch_min: "最小桨距角漂移 (°)",
};

export const FARM_VALUE_TITLES = {
  yaw_error: "全场静态偏航误差",
  yaw_count: "全场偏航次数",
  pitch_min: "全场最小桨距角漂移",
};

export const FARM_SERIES_TITLES = {
  wind_power_curve: "全场功率曲线分析",
  wind_power_scatter: "全场风功率散点分析",
  yaw_static: "全场静态偏航异常分布",
  yaw_twist: "全场扭缆分析",
  pitch_regulation: "全场变桨一致性分析",
  pitch_coord: "全场变桨协调分析",
  ctrl_power_quality: "全场电能质量分析",
  ctrl_op_state: "全场运行状态分析",
  ctrl_deload: "全场降载判定分析",
  aero_cp: "全场Cp功率系数分析",
  aero_tsr: "全场TSR叶尖速比分析",
  aero_tsr_wind: "全场TSR-Cp联合分析",
};

export function resolveTemplateKey(options = {}, detectorKey = "") {
  if (options.templateKey) return options.templateKey;
  const key = options.detectorKey || options.poKey || detectorKey || "";
  return PO_TO_TEMPLATE_KEY[key] || options.detectorName || "";
}

export function isYawErrorDetector(templateKey) {
  return templateKey === "yaw_error";
}

export function isYawCountDetector(templateKey) {
  return templateKey === "yaw_count";
}

export function isPitchMinDetector(templateKey) {
  return templateKey === "pitch_min";
}

export function isFarmAggregateJson(plotJson) {
  return Boolean(
    plotJson &&
      (plotJson.chartType === "series" || plotJson.chartType === "value") &&
      Array.isArray(plotJson.turbines),
  );
}

/** 多图检测器：顶层 chartType=panels，每个 panel 自带 turbines */
export function isFarmPanelsJson(plotJson) {
  return Boolean(
    plotJson &&
      plotJson.chartType === "panels" &&
      Array.isArray(plotJson.panels) &&
      plotJson.panels.some((panel) => Array.isArray(panel?.turbines)),
  );
}

export function isFarmPlotJson(plotJson) {
  return isFarmAggregateJson(plotJson) || isFarmPanelsJson(plotJson);
}

export function isValueBarPanel(panel) {
  return panel?.chartKind === "valueBar";
}

export function isBubbleColorbar(row = {}, templateKey = "") {
  if (isPitchMinDetector(templateKey)) return true;
  return /点数/.test(String(row.colorbarTitle || row.colorbartitle || ""));
}

/** 最小桨距角仅用点数上色，点径统一，不再按点数缩放气泡 */
export function usesBubbleSymbolSize(row = {}, templateKey = "") {
  if (isPitchMinDetector(templateKey)) return false;
  return /点数/.test(String(row.colorbarTitle || row.colorbartitle || ""));
}

/**
 * 连续色映射取值：优先 colorbar，其次数值型 pointData（与 x/y 同下标）。
 * 点数色带即用该序列控制每个点的颜色深浅。
 */
export function resolveRowColorMetric(row = {}, length = 0) {
  const len =
    Number(length) > 0
      ? Number(length)
      : Math.min(
          Array.isArray(row?.xData) ? row.xData.length : 0,
          Array.isArray(row?.yData) ? row.yData.length : 0,
        );
  if (!len) return [];
  const colorbar = row.colorbar || row.colorBar;
  if (Array.isArray(colorbar) && colorbar.length >= len) {
    return colorbar.slice(0, len).map((v) => {
      const n = Number(v);
      return Number.isFinite(n) ? n : 0;
    });
  }
  const pointData = row.pointData;
  if (!Array.isArray(pointData) || pointData.length < len) return [];
  // pointData 若为悬停对象数组则不可作色值
  if (pointData.some((item) => item != null && typeof item === "object")) {
    return [];
  }
  return pointData.slice(0, len).map((v) => {
    const n = Number(v);
    return Number.isFinite(n) ? n : 0;
  });
}

/** 点数大的点后绘制（盖在浅色点之上），并写入更高 z */
export function sortScatterPairsByColorMetricAsc(pairs = []) {
  if (!Array.isArray(pairs) || pairs.length < 2) {
    return attachCountRenderZ(pairs);
  }
  const metricOf = (item) => {
    const value = Array.isArray(item) ? item : item?.value;
    if (!Array.isArray(value) || value.length < 3) return 0;
    const n = Number(value[2]);
    return Number.isFinite(n) ? n : 0;
  };
  return attachCountRenderZ(
    [...pairs].sort((a, b) => metricOf(a) - metricOf(b)),
  );
}

function attachCountRenderZ(pairs = []) {
  if (!Array.isArray(pairs) || !pairs.length) return pairs;
  return pairs.map((item) => {
    const value = Array.isArray(item) ? item : item?.value;
    const count =
      Array.isArray(value) && value.length >= 3 ? Number(value[2]) : 0;
    const z = Number.isFinite(count) ? Math.max(1, Math.round(count)) : 1;
    if (Array.isArray(item)) return { value: item, z };
    return { ...item, z };
  });
}

export function findPeakCoord(xArr = [], yArr = []) {
  const len = Math.min(xArr.length, yArr.length);
  if (!len) return null;
  let maxIdx = 0;
  let maxY = Number(yArr[0]);
  for (let i = 1; i < len; i += 1) {
    const y = Number(yArr[i]);
    if (Number.isFinite(y) && (!Number.isFinite(maxY) || y > maxY)) {
      maxY = y;
      maxIdx = i;
    }
  }
  if (!Number.isFinite(maxY)) return null;
  return { x: xArr[maxIdx], y: maxY, index: maxIdx };
}

/** 仅透传 JSON 中的小标题字段，不做前端拼接 */
export function resolvePanelSubtitle(panel = {}, plotJson = {}) {
  const text =
    panel.subtitle ??
    panel.subtext ??
    panel.panelSubtitle ??
    plotJson.subtitle ??
    plotJson.subtext ??
    "";
  return String(text || "").trim();
}

function copyPanelMeta(panel, plotJson = {}) {
  return {
    panelKey: panel.key || "",
    title: panel.panelTitle || panel.title || plotJson.title || "",
    subtitle: resolvePanelSubtitle(panel, plotJson),
    xaxis: panel.xaxis || plotJson.xaxis || "",
    yaxis: panel.yaxis || plotJson.yaxis || "",
    xrange: panel.xrange || plotJson.xrange,
    yrange: panel.yrange || plotJson.yrange,
    data: panel.data || [],
    rawMeans: panel.rawMeans,
    detectorName:
      plotJson.detector_name ||
      plotJson.analysisType ||
      plotJson.detector ||
      "",
  };
}

export function unwrapFarmPlotJson(raw) {
  if (!raw || typeof raw !== "object") return null;
  if (raw.__imageUrl) return raw;
  if (isFarmPlotJson(raw)) return raw;
  if (raw.data && isFarmPlotJson(raw.data)) return raw.data;
  return raw;
}

/** panels[] 里自带 turbines 的分面，按全场叠加图规则展开 */
function farmPanelToPanel(panel = {}, farmJson = {}, options = {}) {
  const title = panel.title || panel.panelTitle || "";
  const [built] = farmAggregateToPanels(
    {
      detector: farmJson.detector || options.templateKey || "",
      farm: farmJson.farm,
      chartType: panel.chartType || "series",
      xaxis: panel.xaxis,
      yaxis: panel.yaxis,
      xrange: panel.xrange,
      yrange: panel.yrange,
      turbines: panel.turbines,
      referenceCurve: panel.referenceCurve || farmJson.referenceCurve,
      referenceCurves: panel.referenceCurves || farmJson.referenceCurves,
      contractCurve: panel.contractCurve || farmJson.contractCurve,
    },
    { ...options, title: title || options.title },
  );
  if (!built) return null;
  return {
    ...built,
    panelKey: panel.key || "",
    title: title || built.title,
    xaxis: panel.xaxis || built.xaxis,
    yaxis: panel.yaxis || built.yaxis,
  };
}

export function extractDetectorPanels(plotJson, options = {}) {
  const json = unwrapFarmPlotJson(plotJson);
  if (!json) return [];
  if (Array.isArray(json.panels) && json.panels.length) {
    return json.panels
      .map((panel) =>
        Array.isArray(panel?.turbines)
          ? farmPanelToPanel(panel, json, options)
          : copyPanelMeta(panel, json),
      )
      .filter(Boolean);
  }
  if (isFarmAggregateJson(json)) {
    return farmAggregateToPanels(json, options);
  }
  return [copyPanelMeta(json, json)];
}

function formatTurbineLabel(name, nameMap = {}) {
  const raw = String(name || "");
  if (!raw) return "--";
  const mapped = nameMap[raw] || nameMap[String(raw)];
  const text = mapped ? String(mapped) : raw;
  if (/号$/.test(text)) return text;
  if (/^\d+$/.test(text)) return `${text}号`;
  return text;
}

function meanOf(values = []) {
  const nums = values.map(Number).filter((n) => Number.isFinite(n));
  if (!nums.length) return null;
  return nums.reduce((sum, n) => sum + n, 0) / nums.length;
}

function farmSeriesMode(detector, item = {}) {
  if (item.xType === "time") return "markers";
  if (detector === "wind_power_curve") return "lines";
  if (detector === "pitch_regulation") return "lines+markers";
  return "markers";
}

function referenceCurveDisplayLabel(item = {}) {
  const text = String(item.label || "合同功率曲线");
  if (/合同功率/.test(text)) return "合同功率曲线";
  if (/近90日/.test(text)) return "近90日功率曲线";
  if (/参考功率|理论功率|参考曲线/.test(text)) return "参考功率曲线";
  return text;
}

function buildReferenceCurveRow(item) {
  if (!item || typeof item !== "object") return null;
  const xData = Array.isArray(item.xData)
    ? item.xData
    : Array.isArray(item.x)
    ? item.x
    : [];
  const yData = Array.isArray(item.yData)
    ? item.yData
    : Array.isArray(item.y)
    ? item.y
    : [];
  if (!xData.length) return null;
  const label = referenceCurveDisplayLabel(item);
  return {
    label,
    originalLabel: item.label || label,
    mode: "lines",
    xData,
    yData,
    timeData: Array.isArray(item.timeData) ? item.timeData : [],
    __shared: true,
    __farm: true,
    extra: item,
  };
}

function collectFarmReferenceRows(farmJson = {}) {
  const list = [];
  if (farmJson.referenceCurve) list.push(farmJson.referenceCurve);
  if (Array.isArray(farmJson.referenceCurves)) {
    list.push(...farmJson.referenceCurves);
  }
  if (farmJson.contractCurve) list.push(farmJson.contractCurve);
  const rows = list.map(buildReferenceCurveRow).filter(Boolean);
  const seen = new Set();
  return rows.filter((row) => {
    if (seen.has(row.label)) return false;
    seen.add(row.label);
    return true;
  });
}

/** pointAnomaly[i]===true 才是异常点；字符串 "false" 不能当成 true */
export function isPointAnomalyFlag(flag) {
  return flag === true || flag === 1 || flag === "1" || flag === "true";
}

export function readPointAnomalyFlags(item) {
  if (!item || typeof item !== "object") return null;
  const candidates = [item.pointAnomaly, item.point_anomaly];
  if (!Array.isArray(item.pointAnomaly) && item.extra && item.extra !== item) {
    candidates.push(item.extra.pointAnomaly, item.extra.point_anomaly);
  }
  for (let i = 0; i < candidates.length; i += 1) {
    const raw = candidates[i];
    if (Array.isArray(raw)) return raw;
    if (typeof raw === "string" && raw.trim().startsWith("[")) {
      try {
        const parsed = JSON.parse(raw);
        if (Array.isArray(parsed)) return parsed;
      } catch (_error) {
        /* 忽略无法解析的标记 */
      }
    }
  }
  return null;
}

/**
 * 按 pointAnomaly 把一条折线拆成首尾相接的红/蓝段。
 * 相邻点只要有一端是异常，这段线就是红线，正常点之间是蓝线。
 */
export function splitConnectedLineByPointAnomaly(xData = [], yData = [], flags) {
  const len = Math.min(xData.length, yData.length);
  const hasFlags = Array.isArray(flags) && flags.length > 0;
  const flagged = (index) => hasFlags && isPointAnomalyFlag(flags[index]);
  if (!len) return [];
  if (!hasFlags || len === 1) {
    return [
      {
        anomaly: flagged(0),
        xData: xData.slice(0, len),
        yData: yData.slice(0, len),
      },
    ];
  }
  const segments = [];
  let start = 0;
  let anomaly = flagged(0) || flagged(1);
  for (let index = 1; index < len - 1; index += 1) {
    const next = flagged(index) || flagged(index + 1);
    if (next === anomaly) continue;
    segments.push({
      anomaly,
      xData: xData.slice(start, index + 1),
      yData: yData.slice(start, index + 1),
    });
    start = index;
    anomaly = next;
  }
  segments.push({
    anomaly,
    xData: xData.slice(start, len),
    yData: yData.slice(start, len),
  });
  return segments.filter((segment) => segment.xData.length > 0);
}

function farmSeriesKind(item = {}, detector = "") {
  // 风功率散点没有逐点 pointAnomaly 时，不按整机 anomaly 把全部点画红
  if (detector === "wind_power_scatter") return "正常";
  if (item.status) return String(item.status);
  if (item.anomaly) return "异常";
  return "正常";
}

function sliceByFlag(item, flags, keepAnomaly) {
  const xData = [];
  const yData = [];
  const timeData = [];
  const sourceX = item.xData || [];
  const sourceY = item.yData || [];
  const sourceTime = Array.isArray(item.timeData) ? item.timeData : [];
  const len = Math.min(sourceX.length, sourceY.length);
  for (let idx = 0; idx < len; idx += 1) {
    // pointAnomaly[i] 与 xData/yData 同下标；缺省按正常(false)
    const flagged = isPointAnomalyFlag(flags[idx]);
    if (flagged !== keepAnomaly) continue;
    xData.push(sourceX[idx]);
    yData.push(sourceY[idx]);
    if (sourceTime[idx] != null) timeData.push(sourceTime[idx]);
  }
  return { xData, yData, timeData };
}

/** 变桨一致性等检测器：一台风机内按桨叶分多条曲线 */
function buildFarmBladeRows(item, turbineName, mode) {
  const turbineAnomaly = Boolean(item.anomaly);
  return (item.blades || [])
    .filter((blade) => blade && Array.isArray(blade.xData))
    .map((blade) => {
      const bladeLabel = blade.label || "";
      return {
        label: `${turbineName} ${bladeLabel}`.trim(),
        originalLabel: bladeLabel,
        mode,
        xData: blade.xData || [],
        yData: blade.yData || [],
        timeData: Array.isArray(blade.timeData)
          ? blade.timeData
          : item.xType === "time"
          ? blade.xData || []
          : [],
        __farm: true,
        anomaly: turbineAnomaly,
        pointAnomaly: Array.isArray(blade.pointAnomaly)
          ? blade.pointAnomaly
          : Array.isArray(blade.point_anomaly)
          ? blade.point_anomaly
          : Array.isArray(item.pointAnomaly)
          ? item.pointAnomaly
          : Array.isArray(item.point_anomaly)
          ? item.point_anomaly
          : undefined,
        extra: {
          ...item,
          anomaly: turbineAnomaly,
          bladeLabel,
        },
      };
    });
}

function isJsonAnomalyFlag(flag) {
  return flag === true || flag === 1 || flag === "1" || flag === "true";
}

function buildFarmSeriesRows(item, detector, nameMap) {
  const turbineName = formatTurbineLabel(item.turbine, nameMap);
  const mode = farmSeriesMode(detector, item);
  // 功率曲线整机是否异常只看 JSON 的 anomaly，不用 status / pointAnomaly
  if (detector === "wind_power_curve") {
    const turbineAnomaly = isJsonAnomalyFlag(item.anomaly);
    const kind = turbineAnomaly ? "异常" : "正常";
    return [
      {
        label: `${turbineName} ${kind}`,
        originalLabel: kind,
        mode,
        xData: item.xData || [],
        yData: item.yData || [],
        timeData: Array.isArray(item.timeData) ? item.timeData : [],
        __farm: true,
        anomaly: turbineAnomaly,
        extra: { ...item, anomaly: turbineAnomaly },
      },
    ];
  }
  if (Array.isArray(item.blades) && item.blades.length) {
    return buildFarmBladeRows(item, turbineName, mode);
  }
  // 桨叶极差：保留整条折线和 pointAnomaly，由图表按段接成红蓝线
  if (detector === "pitch_regulation") {
    const pitchFlags = readPointAnomalyFlags(item);
    return [
      {
        label: turbineName,
        originalLabel: turbineName,
        mode,
        xData: item.xData || [],
        yData: item.yData || [],
        timeData: Array.isArray(item.timeData)
          ? item.timeData
          : item.xType === "time"
          ? item.xData || []
          : [],
        pointAnomaly: pitchFlags || undefined,
        __farm: true,
        anomaly: Boolean(item.anomaly),
        extra: {
          ...item,
          anomaly: Boolean(item.anomaly),
          turbineName,
        },
      },
    ];
  }
  const flags = readPointAnomalyFlags(item) || [];
  // 有 pointAnomaly 时按同下标拆分：false=正常点、true=异常点（不以整机 anomaly 覆盖）
  const canSplit = flags.length > 0;
  const rows = canSplit
    ? [
        { kind: "正常", sliced: sliceByFlag(item, flags, false) },
        { kind: "异常", sliced: sliceByFlag(item, flags, true) },
      ].filter((row) => row.sliced.xData.length)
    : [{ kind: farmSeriesKind(item, detector), sliced: null }];

  return rows.map((row) => {
    const sliced = row.sliced;
    const pointAnomalyFlag = canSplit
      ? row.kind === "异常"
      : Boolean(item.anomaly);
    return {
      label: `${turbineName} ${row.kind}`,
      originalLabel: row.kind,
      mode,
      xData: sliced ? sliced.xData : item.xData || [],
      yData: sliced ? sliced.yData : item.yData || [],
      timeData: sliced
        ? sliced.timeData
        : item.xType === "time"
        ? item.xData || []
        : [],
      pointAnomaly: canSplit ? undefined : item.pointAnomaly,
      __farm: true,
      anomaly: pointAnomalyFlag,
      // 行级 anomaly 写入 extra，避免着色仍读到整机 anomaly
      extra: { ...item, anomaly: pointAnomalyFlag },
    };
  });
}

export function farmAggregateToPanels(farmJson = {}, options = {}) {
  const detector = farmJson.detector || options.templateKey || "";
  const turbines = Array.isArray(farmJson.turbines) ? farmJson.turbines : [];
  const nameMap = options.nameMap || {};
  const title =
    options.title ||
    FARM_VALUE_TITLES[detector] ||
    FARM_SERIES_TITLES[detector] ||
    farmJson.farm ||
    "全场检测汇总";
  if (farmJson.chartType === "value") {
    const values = turbines.map((item) => Number(item.value));
    const categories = turbines.map((item) =>
      formatTurbineLabel(item.turbine, nameMap),
    );
    const valuePanel = {
      chartKind: "valueBar",
      title,
      detectorName: detector,
      xaxis: "风机",
      yaxis: FARM_VALUE_AXIS[detector] || "检测值",
      categories,
      values,
      anomalyFlags: turbines.map((item) => Boolean(item.anomaly)),
      extras: turbines,
      mean: meanOf(values),
    };
    if (detector === "yaw_count" || detector === "pitch_min") {
      return [{ ...valuePanel, colorMode: "farmStatus", showMean: false }];
    }
    if (detector !== "yaw_error") return [valuePanel];
    return [
      {
        ...valuePanel,
        title,
        xaxis: "机组编号",
        yaxis: "静态偏航误差（度）",
        values,
        colorMode: "yawErrorAbs",
        showMean: false,
      },
    ];
  }

  return [
    {
      title,
      xaxis: farmJson.xaxis || "",
      yaxis: farmJson.yaxis || "",
      xrange: farmJson.xrange,
      yrange: farmJson.yrange,
      detectorName: detector,
      data: turbines
        .flatMap((item, turbineIndex) =>
          buildFarmSeriesRows(item, detector, nameMap).map((row) => ({
            ...row,
            turbineIndex,
            engineName: formatTurbineLabel(item.turbine, nameMap),
          })),
        )
        .concat(collectFarmReferenceRows(farmJson)),
    },
  ];
}

export function formatPointHover(point) {
  if (!point || typeof point !== "object") return "";
  const lines = [];
  if (point.dataTime) lines.push(`时间: ${point.dataTime}`);
  const appendMap = (obj, prefix) => {
    if (!obj || typeof obj !== "object") return;
    Object.keys(obj).forEach((key) => {
      const val = obj[key];
      if (val == null || val === "") return;
      lines.push(`${prefix}${key}: ${val}`);
    });
  };
  appendMap(point.raw, "");
  appendMap(point.deviations, "");
  appendMap(point.deviation, "偏差 ");
  appendMap(point.mean, "均值 ");
  appendMap(point.meanDeviation, "均值偏差 ");
  return lines.join("<br/>");
}

export function formatFarmSeriesHover(extra = {}, detector = "") {
  if (!extra || typeof extra !== "object") return "";
  const lines = [];
  const push = (label, val, suffix = "") => {
    if (val == null || val === "") return;
    lines.push(`${label}: ${val}${suffix}`);
  };
  if (extra.bladeLabel) {
    const turbine =
      extra.turbineName != null ? String(extra.turbineName) : "";
    const turbineText = turbine
      ? /号$/.test(turbine)
        ? turbine
        : `${turbine}号`
      : "";
    lines.push([turbineText, extra.bladeLabel].filter(Boolean).join(" "));
  }
  push("状态", extra.status);
  push("发电量比值", extra.ratio);
  push("异常点数", extra.anomalyPoints);
  push("降载占比", extra.deloadRatio);
  if (detector === "yaw_error") {
    push("发电量损失", extra.powerloss, "%");
    push("覆盖率", extra.coverage);
  }
  if (detector === "yaw_count") {
    push("CW", extra.cw, "次");
    push("CCW", extra.ccw, "次");
  }
  if (detector === "pitch_min") {
    push("P10", extra.p10, "°");
    push("基线", extra.baseline, "°");
  }
  return lines.join("<br/>");
}

export function formatFarmValueHover(extra = {}, detector = "") {
  if (!extra || typeof extra !== "object") return "";
  const lines = [];
  const push = (label, val, suffix = "") => {
    if (val == null || val === "") return;
    lines.push(`${label}: ${val}${suffix}`);
  };
  if (detector === "yaw_error") {
    push("发电量损失", extra.powerloss, "%");
    push(
      "覆盖率",
      extra.coverage != null ? Number(extra.coverage) : extra.coverage,
    );
  } else if (detector === "yaw_count") {
    push("CW", extra.cw, "次");
    push("CCW", extra.ccw, "次");
  } else if (detector === "pitch_min") {
    push("漂移", extra.value, "°");
    push("P10", extra.p10, "°");
    push("基线", extra.baseline, "°");
  } else {
    push("数值", extra.value);
  }
  return lines.join("<br/>");
}

export function scaleBubbleSize(
  value,
  min,
  max,
  { minSize = 8, maxSize = 28 } = {},
) {
  const num = Number(value);
  if (!Number.isFinite(num)) return minSize;
  if (!Number.isFinite(min) || !Number.isFinite(max) || max <= min) return 14;
  const ratio = (num - min) / (max - min);
  return minSize + ratio * (maxSize - minSize);
}

/** 异常检测报告数值轴刻度：最多保留 2 位小数 */
export function formatReportValueAxisLabel(value, fractionDigits = 2) {
  const n = Number(value);
  if (!Number.isFinite(n)) return String(value ?? "");
  const rounded = Number(n.toFixed(fractionDigits));
  return rounded.toLocaleString("zh-CN", {
    minimumFractionDigits: 0,
    maximumFractionDigits: fractionDigits,
  });
}