using FluentAssertions;
using Marathon.Domain.AnomalyDetection;
using Marathon.Domain.Enums;

namespace Marathon.Domain.Tests.AnomalyDetection;

/// <summary>
/// Unit tests for <see cref="AnomalyEvidenceParser"/> covering happy path,
/// two-way (no draw), and malformed JSON tolerance.
/// </summary>
public sealed class AnomalyEvidenceParserTests
{
    [Fact]
    public void Should_Parse_ThreeWayEvidence_With_DrawOutcome()
    {
        const string json = """
            {
              "suspensionGapSeconds": 90,
              "preSuspension": {
                "capturedAt": "2026-05-10T18:00:00+03:00",
                "p1": 0.55, "pDraw": 0.20, "p2": 0.25,
                "rate1": 1.8, "rateDraw": 4.5, "rate2": 4.0
              },
              "postSuspension": {
                "capturedAt": "2026-05-10T18:02:30+03:00",
                "p1": 0.25, "pDraw": 0.20, "p2": 0.55,
                "rate1": 4.0, "rateDraw": 4.5, "rate2": 1.8
              }
            }
            """;

        var parsed = AnomalyEvidenceParser.TryParse(json, out var data);

        parsed.Should().BeTrue();
        data.SuspensionGapSeconds.Should().Be(90);
        data.PreSuspension.P1.Should().Be(0.55m);
        data.PreSuspension.PDraw.Should().Be(0.20m);
        data.PreSuspension.Favourite.Should().Be(Side.Side1, "Side1 had the highest pre-suspension probability");
        data.PostSuspension.Favourite.Should().Be(Side.Side2, "Side2 became favourite after the flip");
    }

    [Fact]
    public void Should_Parse_TwoWayEvidence_With_NullDraw()
    {
        const string json = """
            {
              "suspensionGapSeconds": 75,
              "preSuspension": {
                "capturedAt": "2026-05-10T18:00:00+03:00",
                "p1": 0.70, "p2": 0.30,
                "rate1": 1.4, "rate2": 3.3
              },
              "postSuspension": {
                "capturedAt": "2026-05-10T18:01:30+03:00",
                "p1": 0.30, "p2": 0.70,
                "rate1": 3.3, "rate2": 1.4
              }
            }
            """;

        var parsed = AnomalyEvidenceParser.TryParse(json, out var data);

        parsed.Should().BeTrue();
        data.PreSuspension.PDraw.Should().BeNull("tennis has no draw outcome");
        data.PreSuspension.RateDraw.Should().BeNull();
        data.PreSuspension.Favourite.Should().Be(Side.Side1);
        data.PostSuspension.Favourite.Should().Be(Side.Side2);
    }

    [Fact]
    public void Should_ReturnFalse_When_JsonIsNullOrEmpty()
    {
        AnomalyEvidenceParser.TryParse(null, out _).Should().BeFalse();
        AnomalyEvidenceParser.TryParse(string.Empty, out _).Should().BeFalse();
        AnomalyEvidenceParser.TryParse("   ", out _).Should().BeFalse();
    }

    [Fact]
    public void Should_ReturnFalse_When_JsonIsMalformed()
    {
        AnomalyEvidenceParser.TryParse("{not json", out _).Should().BeFalse();
    }

    [Fact]
    public void Should_ReturnFalse_When_PreOrPostSuspensionMissing()
    {
        const string onlyPre = """
            {
              "suspensionGapSeconds": 90,
              "preSuspension": {
                "capturedAt": "2026-05-10T18:00:00+03:00",
                "p1": 0.55, "p2": 0.25, "rate1": 1.8, "rate2": 4.0
              }
            }
            """;

        AnomalyEvidenceParser.TryParse(onlyPre, out _).Should().BeFalse();
    }

    [Fact]
    public void Favourite_Should_Be_Draw_When_DrawIsMostLikely()
    {
        const string json = """
            {
              "suspensionGapSeconds": 60,
              "preSuspension": {
                "capturedAt": "2026-05-10T18:00:00+03:00",
                "p1": 0.30, "pDraw": 0.50, "p2": 0.20,
                "rate1": 3.3, "rateDraw": 2.0, "rate2": 5.0
              },
              "postSuspension": {
                "capturedAt": "2026-05-10T18:01:00+03:00",
                "p1": 0.30, "pDraw": 0.50, "p2": 0.20,
                "rate1": 3.3, "rateDraw": 2.0, "rate2": 5.0
              }
            }
            """;

        AnomalyEvidenceParser.TryParse(json, out var data).Should().BeTrue();
        data.PreSuspension.Favourite.Should().Be(Side.Draw);
    }
}