using TeamUp.Modules.Skills.Domain;
using TeamUp.Modules.Skills.Eval;
using Xunit;

namespace TeamUp.IntegrationTests;

/// <summary>Unit coverage for the eval harness (no database). Uses a stub executor for the model.</summary>
public sealed class SkillEvaluatorTests
{
    private sealed class StubExecutor(Func<string, string> respond) : ISkillExecutor
    {
        public Task<string> ExecuteAsync(string skillBody, string input, CancellationToken cancellationToken = default) =>
            Task.FromResult(respond(input));
    }

    private static List<GoldenExample> Golden(string input, string expected) =>
        [new GoldenExample { Input = input, Expected = expected }];

    [Fact]
    public async Task Passes_when_output_matches_expected()
    {
        var report = await new SkillEvaluator().EvaluateAsync(
            Golden("anything", "a clear logout button in the header"),
            "body",
            new StubExecutor(_ => "a clear logout button in the header"));

        Assert.True(report.Passed);
        Assert.Equal(0d, report.WorstDistance, precision: 3);
    }

    [Fact]
    public async Task Fails_when_output_diverges()
    {
        var report = await new SkillEvaluator().EvaluateAsync(
            Golden("anything", "a clear logout button in the header"),
            "body",
            new StubExecutor(_ => "something completely unrelated and very different indeed"));

        Assert.False(report.Passed);
        Assert.True(report.WorstDistance > 0.34);
    }

    [Fact]
    public async Task Fails_when_there_are_no_golden_tests()
    {
        var report = await new SkillEvaluator().EvaluateAsync([], "body", new StubExecutor(_ => "x"));
        Assert.False(report.Passed);
    }
}