maraphon-app/tests/Marathon.Application.Tests/Betting/ClosingLineValueCalculatorTests.cs

using FluentAssertions;
using Marathon.Application.Betting;
using Marathon.Domain.Entities;
using Marathon.Domain.Enums;
using Marathon.Domain.ValueObjects;

namespace Marathon.Application.Tests.Betting;

/// <summary>
/// Unit tests for <see cref="ClosingLineValueCalculator"/> covering the math
/// itself and the snapshot-matching path used by the report use case.
/// </summary>
public sealed class ClosingLineValueCalculatorTests
{
    private static readonly EventId EventId = new("11111111");

    [Fact]
    public void Compute_Should_ReturnPositive_When_TakenRate_BeatsClose()
    {
        // Taken 2.20 (implied 0.4545); closed 2.00 (implied 0.5000) → CLV = +0.0455
        var clv = ClosingLineValueCalculator.Compute(takenRate: 2.20m, closingRate: 2.00m);

        clv.Should().BeGreaterThan(0m);
        clv.Should().BeApproximately(0.04545m, 0.00001m);
    }

    [Fact]
    public void Compute_Should_ReturnNegative_When_TakenRate_WorseThanClose()
    {
        // Taken 1.80 (0.5556); closed 2.00 (0.5000) → CLV = -0.0556
        var clv = ClosingLineValueCalculator.Compute(takenRate: 1.80m, closingRate: 2.00m);

        clv.Should().BeLessThan(0m);
        clv.Should().BeApproximately(-0.05556m, 0.00001m);
    }

    [Fact]
    public void Compute_Should_ReturnZero_When_RatesMatch()
    {
        ClosingLineValueCalculator.Compute(2.00m, 2.00m).Should().Be(0m);
    }

    [Theory]
    [InlineData(0)]
    [InlineData(-1)]
    public void Compute_Should_Throw_When_AnyRateIsZeroOrNegative(decimal rate)
    {
        ((Action)(() => ClosingLineValueCalculator.Compute(rate, 2m)))
            .Should().Throw<ArgumentOutOfRangeException>();
        ((Action)(() => ClosingLineValueCalculator.Compute(2m, rate)))
            .Should().Throw<ArgumentOutOfRangeException>();
    }

    [Fact]
    public void TryCompute_Should_ReturnNull_When_NoMatchingBetInSnapshot()
    {
        var taken = new Bet(MatchScope.Instance, BetType.Win, Side.Side1,
            value: null, new OddsRate(2.20m));

        // Snapshot contains only Side2 — no match for Side1 Win.
        var snapshot = new OddsSnapshot(EventId, DateTimeOffset.UtcNow, OddsSource.PreMatch,
            new[] { new Bet(MatchScope.Instance, BetType.Win, Side.Side2, null, new OddsRate(1.70m)) });

        var clv = ClosingLineValueCalculator.TryCompute(2.20m, taken, snapshot);

        clv.Should().BeNull();
    }

    [Fact]
    public void TryCompute_Should_ReturnNull_When_SnapshotIsNull()
    {
        var taken = new Bet(MatchScope.Instance, BetType.Win, Side.Side1, null, new OddsRate(2m));
        ClosingLineValueCalculator.TryCompute(2m, taken, closingSnapshot: null).Should().BeNull();
    }

    [Fact]
    public void TryCompute_Should_MatchOnScopeTypeSideAndValue()
    {
        // Two handicap markets with different thresholds — pick the right one.
        var taken = new Bet(MatchScope.Instance, BetType.WinFora, Side.Side1,
            new OddsValue(-1.5m), new OddsRate(2.20m));

        var snapshot = new OddsSnapshot(EventId, DateTimeOffset.UtcNow, OddsSource.PreMatch,
            new[]
            {
                new Bet(MatchScope.Instance, BetType.WinFora, Side.Side1,
                    new OddsValue(-2.5m), new OddsRate(3.50m)), // wrong threshold
                new Bet(MatchScope.Instance, BetType.WinFora, Side.Side1,
                    new OddsValue(-1.5m), new OddsRate(2.00m)), // match
            });

        var clv = ClosingLineValueCalculator.TryCompute(2.20m, taken, snapshot);

        clv.Should().BeApproximately(0.04545m, 0.00001m);
    }
}