using Admin.NET.Plugin.AiDOP.SmartOps;
using Xunit;

namespace Admin.NET.Plugin.AiDOP.Tests.SmartOps;

public class SmartOpsImprovementEffectivenessTests
{
    [Fact]
    public void Evaluate_InsufficientData_WhenFewerThanThreeSamples()
    {
        var result = SmartOpsImprovementEffectiveness.Evaluate(
            new[] { 1m, 2m },
            new[] { 3m, 4m, 5m },
            10m,
            "higher_is_better");
        Assert.Equal(SmartOpsImprovementEffectiveness.InsufficientData, result.Conclusion);
        Assert.Equal(2, result.BeforeSamples);
    }

    [Fact]
    public void Evaluate_HigherIsBetter_EffectiveWhenMeanUpAndCloserToTarget()
    {
        var before = new[] { 70m, 72m, 71m };
        var after = new[] { 88m, 90m, 91m };
        var result = SmartOpsImprovementEffectiveness.Evaluate(before, after, 100m, "higher_is_better");
        Assert.Equal(SmartOpsImprovementEffectiveness.AutoEffective, result.Conclusion);
        Assert.Equal(3, result.BeforeSamples);
        Assert.Equal(3, result.AfterSamples);
        Assert.True(result.AfterMean > result.BeforeMean);
    }

    [Fact]
    public void Evaluate_LowerIsBetter_EffectiveWhenMeanDownAndCloserToTarget()
    {
        var before = new[] { 12m, 11m, 13m };
        var after = new[] { 8m, 7m, 7.5m };
        var result = SmartOpsImprovementEffectiveness.Evaluate(before, after, 6m, "lower_is_better");
        Assert.Equal(SmartOpsImprovementEffectiveness.AutoEffective, result.Conclusion);
    }

    [Fact]
    public void Evaluate_IneffectiveWhenMeanWorse()
    {
        var result = SmartOpsImprovementEffectiveness.Evaluate(
            new[] { 90m, 91m, 92m },
            new[] { 70m, 68m, 69m },
            100m,
            "higher_is_better");
        Assert.Equal(SmartOpsImprovementEffectiveness.AutoIneffective, result.Conclusion);
    }

    [Fact]
    public void Evaluate_InconclusiveWhenUnchanged()
    {
        var values = new[] { 80m, 80m, 80m };
        var result = SmartOpsImprovementEffectiveness.Evaluate(values, values, 100m, "higher_is_better");
        Assert.Equal(SmartOpsImprovementEffectiveness.AutoInconclusive, result.Conclusion);
        Assert.Equal(0m, result.Delta);
    }

    [Fact]
    public void Evaluate_ReachedTargetCountsAsEffectiveEvenIfOvershoot()
    {
        var result = SmartOpsImprovementEffectiveness.Evaluate(
            new[] { 80m, 81m, 79m },
            new[] { 120m, 121m, 119m },
            100m,
            "higher_is_better");
        Assert.Equal(SmartOpsImprovementEffectiveness.AutoEffective, result.Conclusion);
    }

    [Fact]
    public void Evaluate_InconclusiveWithoutTarget_DoesNotUseSignOnly()
    {
        var result = SmartOpsImprovementEffectiveness.Evaluate(
            new[] { 1m, 2m, 3m },
            new[] { 8m, 9m, 10m },
            null,
            "higher_is_better");
        Assert.Equal(SmartOpsImprovementEffectiveness.AutoInconclusive, result.Conclusion);
    }

    [Fact]
    public void Evaluate_IsDeterministic()
    {
        var before = new[] { 10m, 11m, 12m, 9m };
        var after = new[] { 6m, 5m, 5m, 4m };
        var a = SmartOpsImprovementEffectiveness.Evaluate(before, after, 5m, "lower_is_better");
        var b = SmartOpsImprovementEffectiveness.Evaluate(before, after, 5m, "lower_is_better");
        Assert.Equal(a, b);
        Assert.Equal(SmartOpsImprovementEffectiveness.AutoEffective, a.Conclusion);
        Assert.Equal(3, a.ConsecutiveOnTargetDays);
        Assert.Equal(75m, a.AchievementRate);
    }

    [Fact]
    public void TakeLastValid_KeepsLatestSeven()
    {
        var values = Enumerable.Range(1, 10).Select(x => (decimal?)x).Append(null);
        var taken = SmartOpsImprovementEffectiveness.TakeLastValid(values);
        Assert.Equal(new[] { 4m, 5m, 6m, 7m, 8m, 9m, 10m }, taken);
    }
}