using MembranePoreTester.Models;
using System.Collections.Generic;
using System.Linq;

namespace MembranePoreTester.Helpers
{
    public static class PoreDistributionAnalysis
    {
        public static double CalculateAveragePore(
            IEnumerable<DataPoint> points,
            string unit,
            TestLiquid liquid)
        {
            var sorted = points.OrderBy(p => p.Pressure).ToList();
            if (sorted.Count < 2) return 0;

            double[] pressures = sorted.Select(p => p.Pressure).ToArray();
            double[] dryFlows = sorted.Select(p => p.DryFlow).ToArray();
            double[] wetFlows = sorted.Select(p => p.WetFlow).ToArray();

            double halfDryFlow = dryFlows.Max() / 2.0;

            // 找到湿膜流量等于 halfDryFlow 的压力（交点）
            for (int i = 0; i < wetFlows.Length - 1; i++)
            {
                if ((wetFlows[i] <= halfDryFlow && wetFlows[i + 1] >= halfDryFlow) ||
                    (wetFlows[i] >= halfDryFlow && wetFlows[i + 1] <= halfDryFlow))
                {
                    double p = Interpolation.Linear(
                        new[] { wetFlows[i], wetFlows[i + 1] },
                        new[] { pressures[i], pressures[i + 1] },
                        halfDryFlow);
                    return PoreCalculator.PressureToPore(p, unit, liquid);
                }
            }
            return 0;
        }

        public static double CalculatePoreRangePercentage(
            IEnumerable<DataPoint> points,
            string unit,
            TestLiquid liquid,
            double lowerPore,
            double upperPore)
        {
            var sorted = points.OrderBy(p => p.Pressure).ToList();
            if (sorted.Count < 2) return 0;

            double[] pressures = sorted.Select(p => p.Pressure).ToArray();
            double[] wetFlows = sorted.Select(p => p.WetFlow).ToArray();
            double[] dryFlows = sorted.Select(p => p.DryFlow).ToArray();

            // 大孔径对应低压，小孔径对应高压
            double pLower = PoreCalculator.PoreToPressure(upperPore, unit, liquid);
            double pUpper = PoreCalculator.PoreToPressure(lowerPore, unit, liquid);

            // 插值
            double qWetLower = Interpolation.Linear(pressures, wetFlows, pLower);
            double qDryLower = Interpolation.Linear(pressures, dryFlows, pLower);
            double qWetUpper = Interpolation.Linear(pressures, wetFlows, pUpper);
            double qDryUpper = Interpolation.Linear(pressures, dryFlows, pUpper);

            double ratioLow = qWetLower / qDryLower;
            double ratioHigh = qWetUpper / qDryUpper;

            return (ratioHigh - ratioLow) * 100;
        }
    }
}