using System.Reflection;
using Omika.Core.Observability.External;

namespace Omika.Tests.Observability.External;

/// <summary>Validation de la configuration du pont externe (§74/§75).</summary>
public class ExternalObservabilityOptionsTests
{
    [Fact]
    public void Default_IsDisabled_AndNotUsable()
    {
        var options = new ExternalObservabilityOptions();

        Assert.False(options.Enabled);
        Assert.False(options.IsUsable);
        Assert.Empty(options.Validate());
    }

    [Fact]
    public void Disabled_IsAlwaysValid()
    {
        var options = new ExternalObservabilityOptions
        {
            Enabled = false,
            OtlpEndpoint = "",
            ExportTimeoutSeconds = 0,
            MaxQueueSize = 0
        };

        Assert.Empty(options.Validate());
    }

    [Fact]
    public void Enabled_WithEmptyEndpoint_IsInvalid()
    {
        var options = new ExternalObservabilityOptions { Enabled = true, OtlpEndpoint = "" };

        Assert.False(options.IsUsable);
        Assert.NotEmpty(options.Validate());
    }

    [Fact]
    public void Enabled_WithValidHttpEndpoint_IsUsable()
    {
        var options = new ExternalObservabilityOptions
        {
            Enabled = true,
            OtlpEndpoint = "http://10.0.0.10:4318"
        };

        Assert.True(options.IsUsable);
        Assert.Empty(options.Validate());
    }

    [Fact]
    public void Enabled_WithNonHttpEndpoint_IsInvalid()
    {
        var options = new ExternalObservabilityOptions
        {
            Enabled = true,
            OtlpEndpoint = "ftp://collector:4318"
        };

        Assert.False(options.IsUsable);
        Assert.Contains(options.Validate(), e => e.Contains("http", StringComparison.OrdinalIgnoreCase));
    }

    [Theory]
    [InlineData(0)]
    [InlineData(61)]
    public void ExportTimeoutSeconds_MustBeBetween1And60(int value)
    {
        var options = new ExternalObservabilityOptions
        {
            Enabled = true,
            OtlpEndpoint = "http://localhost:4318",
            ExportTimeoutSeconds = value
        };

        Assert.False(options.IsUsable);
    }

    [Theory]
    [InlineData(0)]
    [InlineData(-1)]
    public void NonPositiveBounds_AreInvalid(int value)
    {
        var options = new ExternalObservabilityOptions
        {
            Enabled = true,
            OtlpEndpoint = "http://localhost:4318",
            MaxQueueSize = value
        };

        Assert.False(options.IsUsable);
    }

    [Fact]
    public void TwoInstances_AreIndependent_NoSharedStaticState()
    {
        var a = new ExternalObservabilityOptions
        {
            Enabled = true,
            OtlpEndpoint = "http://a:4318",
            MaxQueueSize = 111
        };
        var b = new ExternalObservabilityOptions
        {
            Enabled = false,
            OtlpEndpoint = "http://b:4318",
            MaxQueueSize = 222
        };

        // Chaque instance conserve ses propres valeurs (aucune contamination croisée,
        // aucun état statique mutable partagé).
        Assert.True(a.Enabled);
        Assert.Equal("http://a:4318", a.OtlpEndpoint);
        Assert.Equal(111, a.MaxQueueSize);

        Assert.False(b.Enabled);
        Assert.Equal("http://b:4318", b.OtlpEndpoint);
        Assert.Equal(222, b.MaxQueueSize);
    }

    [Fact]
    public void Options_HasNoStaticMutableState()
    {
        // Garde-fou anti-régression (§13/§28) : la config du pont externe ne doit
        // être pilotée par AUCUN champ static mutable (DI-friendly, isolable, testable).
        string[] staticMutable = typeof(ExternalObservabilityOptions)
            .GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static)
            .Where(f => !f.IsInitOnly && !f.IsLiteral)
            .Select(f => f.Name)
            .ToArray();

        Assert.Empty(staticMutable);
    }
}