using FluentAssertions;
using StellaOps.Policy.Engine.Adapters;
using StellaOps.Policy.Exceptions.Models;
using Xunit;

namespace StellaOps.Policy.Engine.Tests.Adapters;

/// <summary>
/// Unit tests for ExceptionEffectRegistry.
/// </summary>
public sealed class ExceptionEffectRegistryTests
{
    private readonly IExceptionEffectRegistry _registry;

    public ExceptionEffectRegistryTests()
    {
        _registry = new ExceptionEffectRegistry();
    }

    [Theory]
    [InlineData(ExceptionType.Vulnerability, ExceptionReason.FalsePositive, PolicyExceptionEffectType.Suppress)]
    [InlineData(ExceptionType.Vulnerability, ExceptionReason.AcceptedRisk, PolicyExceptionEffectType.Suppress)]
    [InlineData(ExceptionType.Vulnerability, ExceptionReason.CompensatingControl, PolicyExceptionEffectType.RequireControl)]
    [InlineData(ExceptionType.Vulnerability, ExceptionReason.TestOnly, PolicyExceptionEffectType.Suppress)]
    [InlineData(ExceptionType.Vulnerability, ExceptionReason.VendorNotAffected, PolicyExceptionEffectType.Suppress)]
    [InlineData(ExceptionType.Vulnerability, ExceptionReason.ScheduledFix, PolicyExceptionEffectType.Defer)]
    [InlineData(ExceptionType.Vulnerability, ExceptionReason.RuntimeMitigation, PolicyExceptionEffectType.Downgrade)]
    [InlineData(ExceptionType.Vulnerability, ExceptionReason.NetworkIsolation, PolicyExceptionEffectType.Downgrade)]
    public void GetEffect_ReturnsCorrectEffect_ForVulnerabilityType(
        ExceptionType type,
        ExceptionReason reason,
        PolicyExceptionEffectType expectedEffect)
    {
        // Act
        var effect = _registry.GetEffect(type, reason);

        // Assert
        effect.Should().NotBeNull();
        effect.Effect.Should().Be(expectedEffect);
    }

    [Theory]
    [InlineData(ExceptionType.Policy, ExceptionReason.FalsePositive, PolicyExceptionEffectType.Suppress)]
    [InlineData(ExceptionType.Policy, ExceptionReason.AcceptedRisk, PolicyExceptionEffectType.Suppress)]
    [InlineData(ExceptionType.Policy, ExceptionReason.CompensatingControl, PolicyExceptionEffectType.RequireControl)]
    [InlineData(ExceptionType.Policy, ExceptionReason.ScheduledFix, PolicyExceptionEffectType.Defer)]
    public void GetEffect_ReturnsCorrectEffect_ForPolicyType(
        ExceptionType type,
        ExceptionReason reason,
        PolicyExceptionEffectType expectedEffect)
    {
        // Act
        var effect = _registry.GetEffect(type, reason);

        // Assert
        effect.Should().NotBeNull();
        effect.Effect.Should().Be(expectedEffect);
    }

    [Theory]
    [InlineData(ExceptionType.Unknown, ExceptionReason.FalsePositive, PolicyExceptionEffectType.Suppress)]
    [InlineData(ExceptionType.Unknown, ExceptionReason.ScheduledFix, PolicyExceptionEffectType.Defer)]
    public void GetEffect_ReturnsCorrectEffect_ForUnknownType(
        ExceptionType type,
        ExceptionReason reason,
        PolicyExceptionEffectType expectedEffect)
    {
        // Act
        var effect = _registry.GetEffect(type, reason);

        // Assert
        effect.Should().NotBeNull();
        effect.Effect.Should().Be(expectedEffect);
    }

    [Theory]
    [InlineData(ExceptionType.Component, ExceptionReason.DeprecationInProgress, PolicyExceptionEffectType.Suppress)]
    [InlineData(ExceptionType.Component, ExceptionReason.Other, PolicyExceptionEffectType.Suppress)] // License waiver
    public void GetEffect_ReturnsCorrectEffect_ForComponentType(
        ExceptionType type,
        ExceptionReason reason,
        PolicyExceptionEffectType expectedEffect)
    {
        // Act
        var effect = _registry.GetEffect(type, reason);

        // Assert
        effect.Should().NotBeNull();
        effect.Effect.Should().Be(expectedEffect);
    }

    [Fact]
    public void GetEffect_ReturnsDefaultDeferral_ForUnmappedCombination()
    {
        // Note: All combinations are mapped, so we test a hypothetical case
        // by checking that the registry handles all known combinations
        var allTypes = Enum.GetValues<ExceptionType>();
        var allReasons = Enum.GetValues<ExceptionReason>();

        foreach (var type in allTypes)
        {
            foreach (var reason in allReasons)
            {
                // Act
                var effect = _registry.GetEffect(type, reason);

                // Assert - should never be null
                effect.Should().NotBeNull();
                effect.Id.Should().NotBeNullOrEmpty();
                effect.Effect.Should().BeOneOf(
                    PolicyExceptionEffectType.Suppress,
                    PolicyExceptionEffectType.Defer,
                    PolicyExceptionEffectType.Downgrade,
                    PolicyExceptionEffectType.RequireControl);
            }
        }
    }

    [Fact]
    public void GetAllEffects_ReturnsDistinctEffects()
    {
        // Act
        var allEffects = _registry.GetAllEffects();

        // Assert
        allEffects.Should().NotBeEmpty();
        allEffects.Should().OnlyHaveUniqueItems(e => e.Id);
    }

    [Fact]
    public void GetEffectById_ReturnsEffect_WhenExists()
    {
        // Act
        var effect = _registry.GetEffectById("suppress");

        // Assert
        effect.Should().NotBeNull();
        effect!.Id.Should().Be("suppress");
        effect.Effect.Should().Be(PolicyExceptionEffectType.Suppress);
    }

    [Fact]
    public void GetEffectById_ReturnsNull_WhenNotExists()
    {
        // Act
        var effect = _registry.GetEffectById("non-existent-effect-id");

        // Assert
        effect.Should().BeNull();
    }

    [Fact]
    public void GetEffectById_IsCaseInsensitive()
    {
        // Act
        var effect1 = _registry.GetEffectById("SUPPRESS");
        var effect2 = _registry.GetEffectById("suppress");
        var effect3 = _registry.GetEffectById("Suppress");

        // Assert
        effect1.Should().Be(effect2);
        effect2.Should().Be(effect3);
    }

    [Fact]
    public void Effects_HaveValidProperties()
    {
        // Act
        var allEffects = _registry.GetAllEffects();

        // Assert
        foreach (var effect in allEffects)
        {
            effect.Id.Should().NotBeNullOrWhiteSpace();
            effect.Name.Should().NotBeNullOrWhiteSpace();
            effect.Description.Should().NotBeNullOrWhiteSpace();
            effect.MaxDurationDays.Should().BeGreaterThan(0);
        }
    }

    [Fact]
    public void DowngradeEffects_HaveValidSeverity()
    {
        // Act
        var downgradeEffects = _registry.GetAllEffects()
            .Where(e => e.Effect == PolicyExceptionEffectType.Downgrade);

        // Assert
        foreach (var effect in downgradeEffects)
        {
            effect.DowngradeSeverity.Should().NotBeNull();
        }
    }

    [Fact]
    public void RequireControlEffects_HaveControlId()
    {
        // Act
        var requireControlEffects = _registry.GetAllEffects()
            .Where(e => e.Effect == PolicyExceptionEffectType.RequireControl);

        // Assert
        foreach (var effect in requireControlEffects)
        {
            effect.RequiredControlId.Should().NotBeNullOrWhiteSpace();
        }
    }

    [Fact]
    public void SuppressEffects_DoNotRequireControl()
    {
        // Act
        var suppressEffects = _registry.GetAllEffects()
            .Where(e => e.Effect == PolicyExceptionEffectType.Suppress);

        // Assert
        foreach (var effect in suppressEffects)
        {
            // Suppress effects should not require controls
            effect.RequiredControlId.Should().BeNull();
        }
    }
}