// ignore_for_file:  constant_identifier_names

import 'dart:math' as math;

import 'package:fis_measure/interfaces/date_types/point.dart';

class GeneralFormulas {
  /// Volume:1/6 x π
  static const double VolumeCofficient = math.pi / 6.0;

  /// 1/6 x π x D1^2 x D2 (D1 ＞ D2)
  ///
  /// 1/6 x π x D1 x D2^2 (D1 ≤ D2)
  ///
  /// return unit: cm³</returns>
  static double volumeTwoLine(double d1, double d2, [bool useBigValue = true]) {
    double volume = 0;
    if (!doubleAlmostEquals(d1, 0) && !doubleAlmostEquals(d2, 0)) {
      if (useBigValue) {
        if (d1 > d2) {
          volume = d1 * d1 * d2 * math.pi / 6.0;
        } else {
          volume = d1 * d2 * d2 * math.pi / 6.0;
        }
      } else {
        if (d1 > d2) {
          volume = d2 * d2 * d1 * math.pi / 6.0;
        } else {
          volume = d1 * d1 * d2 * math.pi / 6.0;
        }
      }
    }
    return volume;
  }

  /// 带比率系数算体积
  ///
  /// [coefficient] 比率系数
  static double volumeWithCoefficient(
    double d1,
    double d2,
    double d3,
    double coefficient,
  ) {
    double volume = 0;
    if (!doubleAlmostEquals(d1, 0) &&
        !doubleAlmostEquals(d2, 0) &&
        !doubleAlmostEquals(d3, 0)) {
      volume = d1 * d2 * d3 * coefficient;
    }
    return volume;
  }

  /// 狭窄率计算
  static double countStenosis(double d1, double d2) {
    double residual;
    double lumen;
    if (d1 > d2) {
      residual = d2;
      lumen = d1;
    } else {
      residual = d1;
      lumen = d2;
    }
    return (1.0 - residual / lumen) * 100;
  }

  static bool doubleAlmostEquals(double num1, double num2,
      [double precision = 0.000001]) {
    if (num1.isNaN && num2.isNaN) return true;
    return (num1 - num2).abs() <= precision;
  }

  /// 点到线的距离
  ///
  /// [pt1] 线端点1
  ///
  /// [pt2] 线端点2
  ///
  /// [pt] 点
  static double distance2Line(DPoint pt1, DPoint pt2, DPoint pt) {
    double dis = 0;
    if (pt1.x == pt2.x) {
      dis = (pt.x - pt1.x).abs();
      return dis;
    }
    var lineK = (pt2.y - pt1.y) / (pt2.x - pt1.x);
    var lineC = (pt2.x * pt1.y - pt1.x * pt2.y) / (pt2.x - pt1.x);
    dis = (lineK * pt.x - pt.y + lineC).abs() / (math.sqrt(lineK * lineK + 1));
    return dis;
  }

  ///计算斜率
  static double countSlope(DPoint p1, DPoint p2) {
    if (doubleAlmostEquals(p2.x, p1.x)) return 0;
    double vertical = p2.y - p1.y;
    double time = (p2.x - p1.x).abs();
    double slope = vertical / time;
    return slope;
  }

  ///计算包络时间
  ///Origin: Vinno.Modules.MeasureModule\Formulas\GeneralFormulas.cs [632:67]
  static double countEnvelopeTime(List<DPoint> points) {
    if (points.length < 2) return 0;
    double startTime = double.maxFinite;
    double endTime = -double.maxFinite;
    for (var point in points) {
      if (point.x < startTime) {
        startTime = point.x;
      }
      if (point.x > endTime) {
        endTime = point.x;
      }
    }
    return (endTime - startTime).abs();
  }

  /// <summary>
  /// 4.0 x V^2
  /// </summary>
  /// <param name="v">Unit cm/s</param>
  /// <returns>Unit mmHg</returns>
  static double countPressure(double v) {
    // The velocity is in cm/s, but it should be m/s in this formula, so divide it by 100.
    double pg = 4.0 * math.pow(v * 0.01, 2);
    return pg;
  }

  /// <summary>
  /// Resistivity Index 阻力指数
  /// <para>RI (ED)=(PS - ED)/PS  </para>
  /// <para>RI (MD)=(PS - MD)/PS  </para>
  /// </summary>
  /// <param name="ps">Unit cm/s</param>
  /// <param name="mdEd">Unit cm/s</param>
  static double countRI(double ps, double mdEd) {
    ps = ps.abs();
    mdEd = mdEd.abs();
    double ri = (ps - mdEd) / ps;
    if (ri < 0) {
      return double.nan;
    }
    return ri;
  }

  /// <summary>
  /// 4.0 x |V1^2 - V2^2|
  /// </summary>
  /// <param name="v1">Unit cm/s</param>
  /// <param name="v2">Unit cm/s</param>
  /// <returns>Unit mmHg</returns>
  static double countMaxPG(double v1, double v2) {
    // The velocity is in cm/s, but it should be m/s in this formula, so divide it by 100.
    double meanPG =
        4.0 * (math.pow(v1 * 0.01, 2) - math.pow(v2 * 0.01, 2)).abs();
    return meanPG;
  }

  // 计算心率
  // TODO: 心脏周期（可配置） DefaultHeartCycle = 2;
  // Origin: Vinno.Modules.MeasureModule\Primitives\DopplerTraceBase.cs
  static double countHR(double timeSpan) {
    const defaultHeartCycle = 1;
    double hr = (defaultHeartCycle * 60 / timeSpan).roundToDouble();
    return hr;
  }

  // return [VTI,tiEnv,timeAveragedVelocity,pv,meanPG,hr];
  static List<double> countVTI(
    List<DPoint> tracePoints,
  ) {
    var tiEnv = 0.0;
    var timeAveragedVelocity = 0.0;
    var pv = 0.0;
    var meanPG = 0.0;
    if (tracePoints.length < 2) return [0, 0, 0, 0, 0, 0];
    int n = tracePoints.length - 1;
    double dis = 0;
    double startTime = 0;
    double endTime = 0;
    double pgSum = 0;
    int positiveCount = 0;
    int negativeCount = 0;
    for (int i = 0; i < n; i++) {
      var p1 = tracePoints[i];
      var p2 = tracePoints[i + 1];
      if (pv.abs() < (p1.y).abs()) {
        pv = p1.y;
      }
      double meanVelocity = (p1.y + p2.y).abs() / 2;
      double timeSpan = (p1.x - p2.x).abs();
      dis += meanVelocity * timeSpan;
      pgSum += countPressure(meanVelocity) * timeSpan;

      if (i == 0) {
        startTime = p1.x;
        endTime = p2.x;
      } else {
        startTime = math.min(startTime, p2.x);
        endTime = math.max(endTime, p2.x);
      }

      if (p1.y < 0) {
        negativeCount++;
      } else {
        positiveCount++;
      }
    }
    if (tracePoints[n].y < 0) {
      negativeCount++;
    } else {
      positiveCount++;
    }
    if (positiveCount < negativeCount) {
      dis = -dis;
    }

    if (pv.abs() < (tracePoints[n].y).abs()) {
      pv = tracePoints[n].y;
    }

    tiEnv = (endTime - startTime).abs();
    meanPG = (pgSum / tiEnv);
    timeAveragedVelocity = (dis / tiEnv);
    var hr = countHR(tiEnv);

    return [dis, tiEnv, timeAveragedVelocity, pv, meanPG, hr];
  }
}