using Omika.Core.Observability.Identity;

namespace Omika.Diagnostics.Tests;

/// <summary>
/// Tests unitaires de l'ActorKey (§19) : HMAC-SHA256 serveur, stable par
/// (tenant, collaborateur), non réversible, fail-open. Aucune clé de production
/// utilisée ici (clés de test déterministes uniquement).
/// </summary>
public class DiagnosticActorKeyTests
{
    private static string KeyA() => Convert.ToBase64String(new byte[32]); // 32 octets 0x00

    private static string KeyB() => Convert.ToBase64String(Enumerable.Repeat((byte)7, 32).ToArray());

    [Fact]
    public void SameTenant_SameCollaborateur_ProducesSameKey()
    {
        var provider = new DiagnosticActorKeyProvider(KeyA());

        DiagnosticActorKey a = provider.Compute("BATIK.01", "42");
        DiagnosticActorKey b = provider.Compute("BATIK.01", "42");

        Assert.True(a.HasValue);
        Assert.Equal(a.Value, b.Value);
        Assert.Equal(a.Version, b.Version);
    }

    [Fact]
    public void DifferentTenant_SameCollaborateur_ProducesDifferentKey()
    {
        var provider = new DiagnosticActorKeyProvider(KeyA());

        DiagnosticActorKey a = provider.Compute("BATIK.01", "42");
        DiagnosticActorKey b = provider.Compute("BATIK.02", "42");

        Assert.NotEqual(a.Value, b.Value);
    }

    [Fact]
    public void SameTenant_DifferentCollaborateur_ProducesDifferentKey()
    {
        var provider = new DiagnosticActorKeyProvider(KeyA());

        DiagnosticActorKey a = provider.Compute("BATIK.01", "42");
        DiagnosticActorKey b = provider.Compute("BATIK.01", "43");

        Assert.NotEqual(a.Value, b.Value);
    }

    [Fact]
    public void DifferentKey_ProducesDifferentActorKey()
    {
        DiagnosticActorKey a = new DiagnosticActorKeyProvider(KeyA()).Compute("BATIK.01", "42");
        DiagnosticActorKey b = new DiagnosticActorKeyProvider(KeyB()).Compute("BATIK.01", "42");

        Assert.True(a.HasValue);
        Assert.True(b.HasValue);
        Assert.NotEqual(a.Value, b.Value);
    }

    [Fact]
    public void ActorKey_IsHexOnly_AndContainsNoNominativeData()
    {
        DiagnosticActorKey key = new DiagnosticActorKeyProvider(KeyA()).Compute("BATIK.01", "42");

        Assert.NotNull(key.Value);
        Assert.Equal(64, key.Value!.Length);
        Assert.Matches("^[0-9a-f]{64}$", key.Value);
        Assert.DoesNotContain("42", key.Value, StringComparison.Ordinal);
        Assert.DoesNotContain("BATIK", key.Value, StringComparison.OrdinalIgnoreCase);
        Assert.DoesNotContain("collaborateur", key.Value, StringComparison.OrdinalIgnoreCase);
    }

    [Fact]
    public void ActorKey_HasStableFormat_Versioned()
    {
        DiagnosticActorKey key = new DiagnosticActorKeyProvider(KeyA()).Compute("BATIK.01", "7");

        Assert.Equal(1, key.Version);
        Assert.NotNull(key.Value);
        Assert.Equal(64, key.Value!.Length);
        Assert.Equal(key.Value.ToLowerInvariant(), key.Value); // hex minuscule
    }

    [Fact]
    public void MissingKey_IsFailOpen_ReturnsEmpty()
    {
        var cases = new[]
        {
            new DiagnosticActorKeyProvider(null),
            new DiagnosticActorKeyProvider(string.Empty),
            new DiagnosticActorKeyProvider("   "),
            new DiagnosticActorKeyProvider("not-base64!!!"),
            new DiagnosticActorKeyProvider(Convert.ToBase64String(new byte[16])) // 128 bits < 256
        };

        foreach (DiagnosticActorKeyProvider provider in cases)
        {
            DiagnosticActorKey key = provider.Compute("BATIK.01", "42");
            Assert.False(key.HasValue);
            Assert.Null(key.Value);
            Assert.Null(key.Version);
        }
    }

    [Fact]
    public void MissingIdentity_IsFailOpen_ReturnsEmpty()
    {
        var provider = new DiagnosticActorKeyProvider(KeyA());

        Assert.False(provider.Compute("", "42").HasValue);
        Assert.False(provider.Compute("   ", "42").HasValue);
        Assert.False(provider.Compute("BATIK.01", null).HasValue);
        Assert.False(provider.Compute("BATIK.01", "").HasValue);
        Assert.False(provider.Compute("BATIK.01", "   ").HasValue);
    }

    [Fact]
    public void CanonicalString_IsVersionedAndDeterministic()
    {
        string a = DiagnosticActorKeyProvider.BuildCanonicalString(1, "BATIK.01", "42");
        string b = DiagnosticActorKeyProvider.BuildCanonicalString(1, "BATIK.01", "42");

        Assert.Equal(a, b);
        Assert.Equal("v1|tenant:BATIK.01|collaborateur:42", a);
    }

    [Fact]
    public void ActorKey_DoesNotRevealIdentity_WhenComparedAcrossTenants()
    {
        // Deux collaborateurs différents ne peuvent pas être confondus, et la clé
        // seule ne permet pas de retrouver le CollaborateurId (§2 : non réversible).
        var provider = new DiagnosticActorKeyProvider(KeyA());
        DiagnosticActorKey key = provider.Compute("BATIK.01", "12345678");

        Assert.NotNull(key.Value);
        Assert.DoesNotContain("12345678", key.Value, StringComparison.Ordinal);
    }
}