using BlueLaminate.Core.Tradeups;
using Xunit;

namespace BlueLaminate.Tests.Tradeups;

public class TradeupMathTests
{
    [Fact]
    public void NormalizedFraction_maps_value_into_its_own_range()
    {
        // Mid-point of a 0.06–0.80 range.
        var frac = TradeupMath.NormalizedFraction(0.43m, 0.06m, 0.80m);
        Assert.Equal(0.5m, frac, precision: 6);
    }

    [Theory]
    [InlineData(-0.5)] // below min
    [InlineData(2.0)]  // above max
    public void NormalizedFraction_clamps_out_of_range_values(double value)
    {
        var frac = TradeupMath.NormalizedFraction((decimal)value, 0.0m, 1.0m);
        Assert.InRange(frac, 0m, 1m);
    }

    [Fact]
    public void NormalizedFraction_returns_zero_for_zero_width_range()
    {
        Assert.Equal(0m, TradeupMath.NormalizedFraction(0.3m, 0.3m, 0.3m));
    }

    [Fact]
    public void OutputFloat_maps_average_fraction_onto_output_range()
    {
        // avg 0.10 onto a 0.00–0.70 output range → 0.07 (the FN/MW boundary).
        var outFloat = TradeupMath.OutputFloat(0.10m, 0.00m, 0.70m);
        Assert.Equal(0.07m, outFloat, precision: 6);
    }

    [Fact]
    public void Full_contract_float_math_matches_hand_calculation()
    {
        // Ten inputs, each normalised to its own range, then averaged and mapped onto the
        // output's 0.00–0.80 range. Five inputs at fraction 0.2 and five at 0.4 → avg 0.3.
        var fractions = new[] { 0.2m, 0.2m, 0.2m, 0.2m, 0.2m, 0.4m, 0.4m, 0.4m, 0.4m, 0.4m };
        var avg = fractions.Sum() / fractions.Length;
        Assert.Equal(0.3m, avg, precision: 6);

        var outFloat = TradeupMath.OutputFloat(avg, 0.00m, 0.80m);
        Assert.Equal(0.24m, outFloat, precision: 6);
        Assert.Equal(WearBand.FieldTested, WearBands.FromFloat(outFloat));
    }
}