using SSPCTester.Devices.Interfaces;
using SSPCTester.Logic.Calculation;
using Xunit;

namespace SSPCTester.Tests;

public class CurveMetricsTests
{
    /// <summary>构造一段 V(t) = Vmax*(1-exp(-t/tau)) 形状的上升曲线。</summary>
    private static CurveData MakeRising(double vMax = 28, double tauSec = 0.0005, int rate = 100_000, double duration = 0.01, double trigger = 0.0025)
    {
        int n = (int)(rate * duration);
        var v = new double[n];
        for (int i = 0; i < n; i++)
        {
            double t = (double)i / rate - trigger;
            v[i] = t <= 0 ? 0 : vMax * (1 - System.Math.Exp(-t / tauSec));
        }
        return new CurveData { SampleRateHz = rate, TriggerTimeSec = trigger, Voltage = v };
    }

    private static CurveData MakeFalling(double vMax = 28, double tauSec = 0.0005, int rate = 100_000, double duration = 0.01, double trigger = 0.0025)
    {
        int n = (int)(rate * duration);
        var v = new double[n];
        for (int i = 0; i < n; i++)
        {
            double t = (double)i / rate - trigger;
            v[i] = t <= 0 ? vMax : vMax * System.Math.Exp(-t / tauSec);
        }
        return new CurveData { SampleRateHz = rate, TriggerTimeSec = trigger, Voltage = v };
    }

    [Fact]
    public void OnTimeMs_ReachesNinetyPercent_AtAboutMinusLogPointOneTau()
    {
        var c = MakeRising();
        double onMs = CurveMetrics.OnTimeMs(c, 28, 0.9);
        // 90% 时刻 t = -tau * ln(0.1) ≈ 1.151 ms
        Assert.InRange(onMs, 1.1, 1.2);
    }

    [Fact]
    public void RiseTimeMs_TenToNinety_AboutTwoPointTwo()
    {
        var c = MakeRising();
        double rt = CurveMetrics.RiseTimeMs(c, 28);
        // ln(0.9/0.1) = ln 9 ≈ 2.197；rt = tau * 2.197 ≈ 1.099 ms
        Assert.InRange(rt, 1.05, 1.15);
    }

    [Fact]
    public void OffTimeMs_FallingToTenPercent()
    {
        var c = MakeFalling();
        double off = CurveMetrics.OffTimeMs(c, 28, 0.1);
        Assert.InRange(off, 1.1, 1.2);
    }

    [Fact]
    public void EstimateVMax_NearActualMax()
    {
        var c = MakeRising();
        double v = CurveMetrics.EstimateVMax(c.Voltage);
        Assert.InRange(v, 27, 28.001);
    }
}

public class PowerLossTests
{
    [Fact]
    public void VoltageDrop_Subtracts()
        => Assert.Equal(1.5, PowerLoss.VoltageDrop(28, 26.5), 3);

    [Fact]
    public void Loss_PinMinusPout()
        => Assert.Equal(28 * 1.0 - 26.5 * 1.0, PowerLoss.LossWatts(28, 1, 26.5, 1), 3);

    [Fact]
    public void Efficiency_Percentage()
    {
        double e = PowerLoss.EfficiencyPct(28, 1, 26.5, 1);
        Assert.InRange(e, 94, 95);
    }

    [Fact]
    public void Efficiency_ZeroInputReturnsZero()
        => Assert.Equal(0.0, PowerLoss.EfficiencyPct(0, 0, 0, 0));
}