using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Text.Json;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Http.Extensions;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;
using Microsoft.Extensions.Primitives;
using Microsoft.IdentityModel.Tokens;
using StellaOps.Configuration;
using StellaOps.Authority.Security;
using StellaOps.Auth.Security.Dpop;
using OpenIddict.Abstractions;
using OpenIddict.Extensions;
using OpenIddict.Server;
using OpenIddict.Server.AspNetCore;
using StellaOps.Auth.Abstractions;
using StellaOps.Authority.OpenIddict;
using StellaOps.Authority.OpenIddict.Handlers;
using StellaOps.Authority.Plugins.Abstractions;
using StellaOps.Authority.Storage.Mongo.Documents;
using StellaOps.Authority.Storage.Mongo.Sessions;
using StellaOps.Authority.Storage.Mongo.Stores;
using StellaOps.Authority.RateLimiting;
using StellaOps.Cryptography.Audit;
using Xunit;
using MongoDB.Bson;
using MongoDB.Driver;
using static StellaOps.Authority.Tests.OpenIddict.TestHelpers;

namespace StellaOps.Authority.Tests.OpenIddict;

public class ClientCredentialsHandlersTests
{
    private static readonly ActivitySource TestActivitySource = new("StellaOps.Authority.Tests");

    [Fact]
    public async Task ValidateClientCredentials_Rejects_WhenScopeNotAllowed()
    {
        var clientDocument = CreateClient(
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "jobs:read");

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var options = TestHelpers.CreateAuthorityOptions();
        var handler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            new TestAuthEventSink(),
            new TestRateLimiterMetadataAccessor(),
            TimeProvider.System,
            new NoopCertificateValidator(),
            new HttpContextAccessor(),
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "jobs:write");
        var context = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);

        await handler.HandleAsync(context);

        Assert.True(context.IsRejected);
        Assert.Equal(OpenIddictConstants.Errors.InvalidScope, context.Error);
        Assert.Equal("Scope 'jobs:write' is not allowed for this client.", context.ErrorDescription);
    }

    [Fact]
    public async Task ValidateClientCredentials_Allows_WhenConfigurationMatches()
    {
        var clientDocument = CreateClient(
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "jobs:read jobs:trigger");

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var options = TestHelpers.CreateAuthorityOptions();
        var handler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            new TestAuthEventSink(),
            new TestRateLimiterMetadataAccessor(),
            TimeProvider.System,
            new NoopCertificateValidator(),
            new HttpContextAccessor(),
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "jobs:read");
        var context = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);

        await handler.HandleAsync(context);

        Assert.False(context.IsRejected, $"Rejected: {context.Error} - {context.ErrorDescription}");
        Assert.False(context.Transaction.Properties.ContainsKey(AuthorityOpenIddictConstants.ClientTenantProperty));
        Assert.Same(clientDocument, context.Transaction.Properties[AuthorityOpenIddictConstants.ClientTransactionProperty]);

        var grantedScopes = Assert.IsType<string[]>(context.Transaction.Properties[AuthorityOpenIddictConstants.ClientGrantedScopesProperty]);
        Assert.Equal(new[] { "jobs:read" }, grantedScopes);
        Assert.Equal(clientDocument.Plugin, context.Transaction.Properties[AuthorityOpenIddictConstants.ClientProviderTransactionProperty]);
    }

    [Fact]
    public async Task ValidateClientCredentials_Allows_NewIngestionScopes()
    {
        var clientDocument = CreateClient(
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "advisory:ingest advisory:read",
            tenant: "tenant-alpha");

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var options = TestHelpers.CreateAuthorityOptions();
        var handler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            new TestAuthEventSink(),
            new TestRateLimiterMetadataAccessor(),
            TimeProvider.System,
            new NoopCertificateValidator(),
            new HttpContextAccessor(),
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "advisory:ingest");
        var context = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);

        await handler.HandleAsync(context);

        Assert.False(context.IsRejected, $"Rejected: {context.Error} - {context.ErrorDescription}");
        var grantedScopes = Assert.IsType<string[]>(context.Transaction.Properties[AuthorityOpenIddictConstants.ClientGrantedScopesProperty]);
        Assert.Equal(new[] { "advisory:ingest" }, grantedScopes);
    }

    [Fact]
    public async Task ValidateClientCredentials_RejectsEffectiveWrite_WhenServiceIdentityMissing()
    {
        var clientDocument = CreateClient(
            clientId: "policy-engine",
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "effective:write findings:read policy:run",
            tenant: "tenant-default");

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var options = TestHelpers.CreateAuthorityOptions();
        var handler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            new TestAuthEventSink(),
            new TestRateLimiterMetadataAccessor(),
            TimeProvider.System,
            new NoopCertificateValidator(),
            new HttpContextAccessor(),
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        Assert.True(clientDocument.Properties.ContainsKey(AuthorityClientMetadataKeys.Tenant));
        Assert.Equal("tenant-default", clientDocument.Properties[AuthorityClientMetadataKeys.Tenant]);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "effective:write");
        var context = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);

        await handler.HandleAsync(context);

        Assert.True(context.IsRejected);
        Assert.Equal(OpenIddictConstants.Errors.UnauthorizedClient, context.Error);
        Assert.Equal("Scope 'effective:write' is reserved for the Policy Engine service identity.", context.ErrorDescription);
    }

    [Fact]
    public async Task ValidateClientCredentials_RejectsEffectiveWrite_WhenTenantMissing()
    {
        var clientDocument = CreateClient(
            clientId: "policy-engine",
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "effective:write findings:read policy:run");
        clientDocument.Properties[AuthorityClientMetadataKeys.ServiceIdentity] = StellaOpsServiceIdentities.PolicyEngine;

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var options = TestHelpers.CreateAuthorityOptions();
        var handler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            new TestAuthEventSink(),
            new TestRateLimiterMetadataAccessor(),
            TimeProvider.System,
            new NoopCertificateValidator(),
            new HttpContextAccessor(),
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "effective:write");
        var context = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);

        await handler.HandleAsync(context);

        Assert.True(context.IsRejected);
        Assert.Equal(OpenIddictConstants.Errors.InvalidClient, context.Error);
        Assert.Equal("Policy Engine service identity requires a tenant assignment.", context.ErrorDescription);
    }

    [Fact]
    public async Task ValidateClientCredentials_AllowsEffectiveWrite_ForPolicyEngineServiceIdentity()
    {
        var clientDocument = CreateClient(
            clientId: "policy-engine",
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "effective:write findings:read policy:run",
            tenant: "tenant-default");
        clientDocument.Properties[AuthorityClientMetadataKeys.ServiceIdentity] = StellaOpsServiceIdentities.PolicyEngine;

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var options = TestHelpers.CreateAuthorityOptions();
        var handler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            new TestAuthEventSink(),
            new TestRateLimiterMetadataAccessor(),
            TimeProvider.System,
            new NoopCertificateValidator(),
            new HttpContextAccessor(),
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "effective:write");
        var context = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);

        await handler.HandleAsync(context);

        Assert.False(context.IsRejected, $"Rejected: {context.Error} - {context.ErrorDescription}");
        var grantedScopes = Assert.IsType<string[]>(context.Transaction.Properties[AuthorityOpenIddictConstants.ClientGrantedScopesProperty]);
        Assert.Equal(new[] { "effective:write" }, grantedScopes);

        var tenant = Assert.IsType<string>(context.Transaction.Properties[AuthorityOpenIddictConstants.ClientTenantProperty]);
        Assert.Equal("tenant-default", tenant);
    }

    [Fact]
    public async Task ValidateClientCredentials_RejectsGraphWrite_WhenServiceIdentityMissing()
    {
        var clientDocument = CreateClient(
            clientId: "cartographer-service",
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "graph:write graph:read",
            tenant: "tenant-default");

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var options = TestHelpers.CreateAuthorityOptions();
        var handler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            new TestAuthEventSink(),
            new TestRateLimiterMetadataAccessor(),
            TimeProvider.System,
            new NoopCertificateValidator(),
            new HttpContextAccessor(),
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "graph:write");
        var context = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);

        await handler.HandleAsync(context);

        Assert.True(context.IsRejected);
        Assert.Equal(OpenIddictConstants.Errors.UnauthorizedClient, context.Error);
        Assert.Equal("Scope 'graph:write' is reserved for the Cartographer service identity.", context.ErrorDescription);
    }

    [Fact]
    public async Task ValidateClientCredentials_RejectsGraphWrite_WhenServiceIdentityMismatch()
    {
        var clientDocument = CreateClient(
            clientId: "cartographer-service",
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "graph:write graph:read",
            tenant: "tenant-default");
        clientDocument.Properties[AuthorityClientMetadataKeys.ServiceIdentity] = StellaOpsServiceIdentities.PolicyEngine;

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var options = TestHelpers.CreateAuthorityOptions();
        var handler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            new TestAuthEventSink(),
            new TestRateLimiterMetadataAccessor(),
            TimeProvider.System,
            new NoopCertificateValidator(),
            new HttpContextAccessor(),
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "graph:write");
        var context = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);

        await handler.HandleAsync(context);

        Assert.True(context.IsRejected);
        Assert.Equal(OpenIddictConstants.Errors.UnauthorizedClient, context.Error);
        Assert.Equal("Scope 'graph:write' is reserved for the Cartographer service identity.", context.ErrorDescription);
    }

    [Fact]
    public async Task ValidateClientCredentials_RejectsGraphScopes_WhenTenantMissing()
    {
        var clientDocument = CreateClient(
            clientId: "graph-api",
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "graph:read graph:export");

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var options = TestHelpers.CreateAuthorityOptions();
        var handler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            new TestAuthEventSink(),
            new TestRateLimiterMetadataAccessor(),
            TimeProvider.System,
            new NoopCertificateValidator(),
            new HttpContextAccessor(),
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "graph:read");
        var context = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);

        await handler.HandleAsync(context);

        Assert.True(context.IsRejected);
        Assert.Equal(OpenIddictConstants.Errors.InvalidClient, context.Error);
        Assert.Equal("Graph scopes require a tenant assignment.", context.ErrorDescription);
    }

    [Fact]
    public async Task ValidateClientCredentials_AllowsGraphRead_WithTenant()
    {
        var clientDocument = CreateClient(
            clientId: "graph-api",
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "graph:read graph:export",
            tenant: "tenant-default");

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var options = TestHelpers.CreateAuthorityOptions();
        var handler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            new TestAuthEventSink(),
            new TestRateLimiterMetadataAccessor(),
            TimeProvider.System,
            new NoopCertificateValidator(),
            new HttpContextAccessor(),
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "graph:read");
        var context = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);

        await handler.HandleAsync(context);

        Assert.False(context.IsRejected, $"Rejected: {context.Error} - {context.ErrorDescription}");
        var grantedScopes = Assert.IsType<string[]>(context.Transaction.Properties[AuthorityOpenIddictConstants.ClientGrantedScopesProperty]);
        Assert.Equal(new[] { "graph:read" }, grantedScopes);
        var tenant = Assert.IsType<string>(context.Transaction.Properties[AuthorityOpenIddictConstants.ClientTenantProperty]);
        Assert.Equal("tenant-default", tenant);
    }

    [Fact]
    public async Task ValidateClientCredentials_AllowsGraphWrite_ForCartographerServiceIdentity()
    {
        var clientDocument = CreateClient(
            clientId: "cartographer-service",
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "graph:write graph:read",
            tenant: "tenant-default");
        clientDocument.Properties[AuthorityClientMetadataKeys.ServiceIdentity] = StellaOpsServiceIdentities.Cartographer;

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var options = TestHelpers.CreateAuthorityOptions();
        var handler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            new TestAuthEventSink(),
            new TestRateLimiterMetadataAccessor(),
            TimeProvider.System,
            new NoopCertificateValidator(),
            new HttpContextAccessor(),
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "graph:write");
        var context = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);

        await handler.HandleAsync(context);

        Assert.False(context.IsRejected, $"Rejected: {context.Error} - {context.ErrorDescription}");
        var grantedScopes = Assert.IsType<string[]>(context.Transaction.Properties[AuthorityOpenIddictConstants.ClientGrantedScopesProperty]);
        Assert.Equal(new[] { "graph:write" }, grantedScopes);
        var tenant = Assert.IsType<string>(context.Transaction.Properties[AuthorityOpenIddictConstants.ClientTenantProperty]);
        Assert.Equal("tenant-default", tenant);
    }

    [Fact]
    public async Task ValidateClientCredentials_EmitsTamperAuditEvent_WhenUnexpectedParametersPresent()
    {
        var clientDocument = CreateClient(
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "jobs:read");

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var sink = new TestAuthEventSink();
        var options = TestHelpers.CreateAuthorityOptions();
        var handler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            sink,
            new TestRateLimiterMetadataAccessor(),
            TimeProvider.System,
            new NoopCertificateValidator(),
            new HttpContextAccessor(),
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "jobs:read");
        transaction.Request?.SetParameter("unexpected_param", "value");

        await handler.HandleAsync(new OpenIddictServerEvents.ValidateTokenRequestContext(transaction));

        var tamperEvent = Assert.Single(sink.Events, record => record.EventType == "authority.token.tamper");
        Assert.Contains(tamperEvent.Properties, property =>
            string.Equals(property.Name, "request.unexpected_parameter", StringComparison.OrdinalIgnoreCase) &&
            string.Equals(property.Value.Value, "unexpected_param", StringComparison.OrdinalIgnoreCase));
    }

    [Fact]
    public async Task ValidateDpopProof_AllowsSenderConstrainedClient()
    {
        var options = TestHelpers.CreateAuthorityOptions(opts =>
        {
            opts.Security.SenderConstraints.Dpop.Enabled = true;
            opts.Security.SenderConstraints.Dpop.Nonce.Enabled = false;
        });

        var clientDocument = CreateClient(
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "jobs:read");
        clientDocument.SenderConstraint = AuthoritySenderConstraintKinds.Dpop;
        clientDocument.Properties[AuthorityClientMetadataKeys.SenderConstraint] = AuthoritySenderConstraintKinds.Dpop;

        using var ecdsa = ECDsa.Create(ECCurve.NamedCurves.nistP256);
        var securityKey = new ECDsaSecurityKey(ecdsa)
        {
            KeyId = Guid.NewGuid().ToString("N")
        };
        var jwk = JsonWebKeyConverter.ConvertFromECDsaSecurityKey(securityKey);
        var expectedThumbprint = ConvertThumbprintToString(jwk.ComputeJwkThumbprint());

        var clientStore = new TestClientStore(clientDocument);
        var auditSink = new TestAuthEventSink();
        var rateMetadata = new TestRateLimiterMetadataAccessor();

        var dpopValidator = new DpopProofValidator(
            Options.Create(new DpopValidationOptions()),
            new InMemoryDpopReplayCache(TimeProvider.System),
            TimeProvider.System,
            NullLogger<DpopProofValidator>.Instance);

        var nonceStore = new InMemoryDpopNonceStore(TimeProvider.System, NullLogger<InMemoryDpopNonceStore>.Instance);

        var dpopHandler = new ValidateDpopProofHandler(
            options,
            clientStore,
            dpopValidator,
            nonceStore,
            rateMetadata,
            auditSink,
            TimeProvider.System,
            TestActivitySource,
            NullLogger<ValidateDpopProofHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "jobs:read");
        transaction.Options = new OpenIddictServerOptions();

        var httpContext = new DefaultHttpContext();
        httpContext.Request.Method = "POST";
        httpContext.Request.Scheme = "https";
        httpContext.Request.Host = new HostString("authority.test");
        httpContext.Request.Path = "/token";

        var now = TimeProvider.System.GetUtcNow();
        var proof = TestHelpers.CreateDpopProof(securityKey, httpContext.Request.Method, httpContext.Request.GetDisplayUrl(), now.ToUnixTimeSeconds());
        httpContext.Request.Headers["DPoP"] = proof;

        transaction.Properties[typeof(HttpContext).FullName!] = httpContext;

        var validateContext = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);
        await dpopHandler.HandleAsync(validateContext);

        Assert.False(validateContext.IsRejected);

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var validateHandler = new ValidateClientCredentialsHandler(
            clientStore,
            registry,
            TestActivitySource,
            auditSink,
            rateMetadata,
            TimeProvider.System,
            new NoopCertificateValidator(),
            new HttpContextAccessor(),
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        await validateHandler.HandleAsync(validateContext);
        Assert.False(validateContext.IsRejected);

        var tokenStore = new TestTokenStore();
        var sessionAccessor = new NullMongoSessionAccessor();
        var handleHandler = new HandleClientCredentialsHandler(
            registry,
            tokenStore,
            sessionAccessor,
            rateMetadata,
            TimeProvider.System,
            TestActivitySource,
            NullLogger<HandleClientCredentialsHandler>.Instance);

        var handleContext = new OpenIddictServerEvents.HandleTokenRequestContext(transaction);
        await handleHandler.HandleAsync(handleContext);
        Assert.True(handleContext.IsRequestHandled);

        var persistHandler = new PersistTokensHandler(
            tokenStore,
            sessionAccessor,
            TimeProvider.System,
            TestActivitySource,
            NullLogger<PersistTokensHandler>.Instance);

        var signInContext = new OpenIddictServerEvents.ProcessSignInContext(transaction)
        {
            Principal = handleContext.Principal,
            AccessTokenPrincipal = handleContext.Principal
        };

        await persistHandler.HandleAsync(signInContext);

        var confirmationClaim = handleContext.Principal?.GetClaim(AuthorityOpenIddictConstants.ConfirmationClaimType);
        Assert.False(string.IsNullOrWhiteSpace(confirmationClaim));

        using (var confirmationJson = JsonDocument.Parse(confirmationClaim!))
        {
            Assert.Equal(expectedThumbprint, confirmationJson.RootElement.GetProperty("jkt").GetString());
        }

        Assert.NotNull(tokenStore.Inserted);
        Assert.Equal(AuthoritySenderConstraintKinds.Dpop, tokenStore.Inserted!.SenderConstraint);
        Assert.Equal(expectedThumbprint, tokenStore.Inserted!.SenderKeyThumbprint);
    }

    [Fact]
    public async Task ValidateDpopProof_IssuesNonceChallenge_WhenNonceMissing()
    {
        var options = new StellaOpsAuthorityOptions
        {
            Issuer = new Uri("https://authority.test")
        };
        options.Security.SenderConstraints.Dpop.Enabled = true;
        options.Security.SenderConstraints.Dpop.Nonce.Enabled = true;
        options.Security.SenderConstraints.Dpop.Nonce.RequiredAudiences.Clear();
        options.Security.SenderConstraints.Dpop.Nonce.RequiredAudiences.Add("signer");
        options.Signing.ActiveKeyId = "test-key";
        options.Signing.KeyPath = "/tmp/test-key.pem";
        options.Storage.ConnectionString = "mongodb://localhost/test";
        Assert.Contains("signer", options.Security.SenderConstraints.Dpop.Nonce.RequiredAudiences);

        var clientDocument = CreateClient(
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "jobs:read",
            allowedAudiences: "signer");
        clientDocument.SenderConstraint = AuthoritySenderConstraintKinds.Dpop;
        clientDocument.Properties[AuthorityClientMetadataKeys.SenderConstraint] = AuthoritySenderConstraintKinds.Dpop;

        using var ecdsa = ECDsa.Create(ECCurve.NamedCurves.nistP256);
        var securityKey = new ECDsaSecurityKey(ecdsa)
        {
            KeyId = Guid.NewGuid().ToString("N")
        };

        var clientStore = new TestClientStore(clientDocument);
        var auditSink = new TestAuthEventSink();
        var rateMetadata = new TestRateLimiterMetadataAccessor();

        var dpopValidator = new DpopProofValidator(
            Options.Create(new DpopValidationOptions()),
            new InMemoryDpopReplayCache(TimeProvider.System),
            TimeProvider.System,
            NullLogger<DpopProofValidator>.Instance);

        var nonceStore = new InMemoryDpopNonceStore(TimeProvider.System, NullLogger<InMemoryDpopNonceStore>.Instance);

        var dpopHandler = new ValidateDpopProofHandler(
            options,
            clientStore,
            dpopValidator,
            nonceStore,
            rateMetadata,
            auditSink,
            TimeProvider.System,
            TestActivitySource,
            NullLogger<ValidateDpopProofHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "jobs:read");
        transaction.Options = new OpenIddictServerOptions();

        var httpContext = new DefaultHttpContext();
        httpContext.Request.Method = "POST";
        httpContext.Request.Scheme = "https";
        httpContext.Request.Host = new HostString("authority.test");
        httpContext.Request.Path = "/token";

        var now = TimeProvider.System.GetUtcNow();
        var proof = TestHelpers.CreateDpopProof(securityKey, httpContext.Request.Method, httpContext.Request.GetDisplayUrl(), now.ToUnixTimeSeconds());
        httpContext.Request.Headers["DPoP"] = proof;

        transaction.Properties[typeof(HttpContext).FullName!] = httpContext;

        var validateContext = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);
        await dpopHandler.HandleAsync(validateContext);

        Assert.True(validateContext.IsRejected);
        Assert.Equal(OpenIddictConstants.Errors.InvalidClient, validateContext.Error);
        var authenticateHeader = Assert.Single(httpContext.Response.Headers.Select(header => header)
            .Where(header => string.Equals(header.Key, "WWW-Authenticate", StringComparison.OrdinalIgnoreCase))).Value;
        Assert.Contains("use_dpop_nonce", authenticateHeader.ToString());
        Assert.True(httpContext.Response.Headers.TryGetValue("DPoP-Nonce", out var nonceValues));
        Assert.False(StringValues.IsNullOrEmpty(nonceValues));
        Assert.Contains(auditSink.Events, record => record.EventType == "authority.dpop.proof.challenge");
    }

    [Fact]
    public async Task ValidateClientCredentials_AllowsMtlsClient_WithValidCertificate()
    {
        var options = new StellaOpsAuthorityOptions
        {
            Issuer = new Uri("https://authority.test")
        };
        options.Security.SenderConstraints.Mtls.Enabled = true;
        options.Security.SenderConstraints.Mtls.RequireChainValidation = false;
        options.Security.SenderConstraints.Mtls.AllowedSanTypes.Clear();
        options.Signing.ActiveKeyId = "test-key";
        options.Signing.KeyPath = "/tmp/test-key.pem";
        options.Storage.ConnectionString = "mongodb://localhost/test";

        var clientDocument = CreateClient(
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "jobs:read");
        clientDocument.SenderConstraint = AuthoritySenderConstraintKinds.Mtls;
        clientDocument.Properties[AuthorityClientMetadataKeys.SenderConstraint] = AuthoritySenderConstraintKinds.Mtls;

        using var rsa = RSA.Create(2048);
        var certificateRequest = new CertificateRequest("CN=mtls-client", rsa, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
        using var certificate = certificateRequest.CreateSelfSigned(DateTimeOffset.UtcNow.AddMinutes(-5), DateTimeOffset.UtcNow.AddHours(1));
        var hexThumbprint = Convert.ToHexString(certificate.GetCertHash(HashAlgorithmName.SHA256));
        clientDocument.CertificateBindings.Add(new AuthorityClientCertificateBinding
        {
            Thumbprint = hexThumbprint
        });

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var auditSink = new TestAuthEventSink();
        var metadataAccessor = new TestRateLimiterMetadataAccessor();
        var httpContextAccessor = new HttpContextAccessor { HttpContext = new DefaultHttpContext() };
        httpContextAccessor.HttpContext!.Connection.ClientCertificate = certificate;

        var validator = new AuthorityClientCertificateValidator(options, TimeProvider.System, NullLogger<AuthorityClientCertificateValidator>.Instance);

        var handler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            auditSink,
            metadataAccessor,
            TimeProvider.System,
            validator,
            httpContextAccessor,
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "jobs:read");
        var context = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);

        await handler.HandleAsync(context);

        Assert.False(context.IsRejected, context.ErrorDescription ?? context.Error);
        Assert.Equal(AuthoritySenderConstraintKinds.Mtls, context.Transaction.Properties[AuthorityOpenIddictConstants.SenderConstraintProperty]);

        var expectedBase64 = Base64UrlEncoder.Encode(certificate.GetCertHash(HashAlgorithmName.SHA256));
        Assert.Equal(expectedBase64, context.Transaction.Properties[AuthorityOpenIddictConstants.MtlsCertificateThumbprintProperty]);
    }

    [Fact]
    public async Task ValidateClientCredentials_RejectsMtlsClient_WhenCertificateMissing()
    {
        var options = new StellaOpsAuthorityOptions
        {
            Issuer = new Uri("https://authority.test")
        };
        options.Security.SenderConstraints.Mtls.Enabled = true;
        options.Signing.ActiveKeyId = "test-key";
        options.Signing.KeyPath = "/tmp/test-key.pem";
        options.Storage.ConnectionString = "mongodb://localhost/test";

        var clientDocument = CreateClient(
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "jobs:read");
        clientDocument.SenderConstraint = AuthoritySenderConstraintKinds.Mtls;
        clientDocument.Properties[AuthorityClientMetadataKeys.SenderConstraint] = AuthoritySenderConstraintKinds.Mtls;

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var httpContextAccessor = new HttpContextAccessor { HttpContext = new DefaultHttpContext() };
        var validator = new AuthorityClientCertificateValidator(options, TimeProvider.System, NullLogger<AuthorityClientCertificateValidator>.Instance);

        var handler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            new TestAuthEventSink(),
            new TestRateLimiterMetadataAccessor(),
            TimeProvider.System,
            validator,
            httpContextAccessor,
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "jobs:read");
        var context = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);

        await handler.HandleAsync(context);

        Assert.True(context.IsRejected);
        Assert.Equal(OpenIddictConstants.Errors.InvalidClient, context.Error);
    }

    [Fact]
    public async Task ValidateClientCredentials_Rejects_WhenAudienceRequiresMtlsButClientConfiguredForDpop()
    {
        var options = TestHelpers.CreateAuthorityOptions(opts =>
        {
            opts.Security.SenderConstraints.Mtls.Enabled = true;
            opts.Security.SenderConstraints.Mtls.EnforceForAudiences.Clear();
            opts.Security.SenderConstraints.Mtls.EnforceForAudiences.Add("signer");
        });

        var clientDocument = CreateClient(
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "jobs:read",
            allowedAudiences: "signer");
        clientDocument.SenderConstraint = AuthoritySenderConstraintKinds.Dpop;
        clientDocument.Properties[AuthorityClientMetadataKeys.SenderConstraint] = AuthoritySenderConstraintKinds.Dpop;

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var handler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            new TestAuthEventSink(),
            new TestRateLimiterMetadataAccessor(),
            TimeProvider.System,
            new NoopCertificateValidator(),
            new HttpContextAccessor(),
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "jobs:read");
        var context = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);

        await handler.HandleAsync(context);

        Assert.True(context.IsRejected);
        Assert.Equal(OpenIddictConstants.Errors.InvalidClient, context.Error);
        Assert.Equal("Requested audiences require mutual TLS sender constraint.", context.ErrorDescription);
    }

    [Fact]
    public async Task ValidateClientCredentials_RequiresMtlsWhenAudienceMatchesEnforcement()
    {
        var options = TestHelpers.CreateAuthorityOptions(opts =>
        {
            opts.Security.SenderConstraints.Mtls.Enabled = true;
            opts.Security.SenderConstraints.Mtls.EnforceForAudiences.Clear();
            opts.Security.SenderConstraints.Mtls.EnforceForAudiences.Add("signer");
        });

        var clientDocument = CreateClient(
            secret: "s3cr3t!",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "jobs:read",
            allowedAudiences: "signer");
        clientDocument.CertificateBindings.Add(new AuthorityClientCertificateBinding
        {
            Thumbprint = "DEADBEEF"
        });

        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(clientDocument));
        var certificateValidator = new RecordingCertificateValidator();
        var httpContextAccessor = new HttpContextAccessor { HttpContext = new DefaultHttpContext() };

        var handler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            new TestAuthEventSink(),
            new TestRateLimiterMetadataAccessor(),
            TimeProvider.System,
            certificateValidator,
            httpContextAccessor,
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, "s3cr3t!", scope: "jobs:read");
        var context = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);

        await handler.HandleAsync(context);

        Assert.True(context.IsRejected);
        Assert.Equal(OpenIddictConstants.Errors.InvalidClient, context.Error);
        Assert.Equal("client_certificate_required", context.ErrorDescription);
        Assert.True(certificateValidator.Invoked);
    }

    [Fact]
    public async Task HandleClientCredentials_PersistsTokenAndEnrichesClaims()
    {
        var clientDocument = CreateClient(
            secret: null,
            clientType: "public",
            allowedGrantTypes: "client_credentials",
            allowedScopes: "jobs:trigger",
            allowedAudiences: "signer",
            tenant: "Tenant-Alpha");

        var descriptor = CreateDescriptor(clientDocument);
        var registry = CreateRegistry(withClientProvisioning: true, clientDescriptor: descriptor);
        var tokenStore = new TestTokenStore();
        var sessionAccessor = new NullMongoSessionAccessor();
        var authSink = new TestAuthEventSink();
        var metadataAccessor = new TestRateLimiterMetadataAccessor();
        var options = TestHelpers.CreateAuthorityOptions();
        var validateHandler = new ValidateClientCredentialsHandler(
            new TestClientStore(clientDocument),
            registry,
            TestActivitySource,
            authSink,
            metadataAccessor,
            TimeProvider.System,
            new NoopCertificateValidator(),
            new HttpContextAccessor(),
            options,
            NullLogger<ValidateClientCredentialsHandler>.Instance);

        var transaction = CreateTokenTransaction(clientDocument.ClientId, secret: null, scope: "jobs:trigger");
        transaction.Options.AccessTokenLifetime = TimeSpan.FromMinutes(30);

        var validateContext = new OpenIddictServerEvents.ValidateTokenRequestContext(transaction);
        await validateHandler.HandleAsync(validateContext);
        Assert.False(validateContext.IsRejected);

        var handler = new HandleClientCredentialsHandler(
            registry,
            tokenStore,
            sessionAccessor,
            metadataAccessor,
            TimeProvider.System,
            TestActivitySource,
            NullLogger<HandleClientCredentialsHandler>.Instance);
        var persistHandler = new PersistTokensHandler(tokenStore, sessionAccessor, TimeProvider.System, TestActivitySource, NullLogger<PersistTokensHandler>.Instance);

        var context = new OpenIddictServerEvents.HandleTokenRequestContext(transaction);

        await handler.HandleAsync(context);

        Assert.True(context.IsRequestHandled);
        Assert.NotNull(context.Principal);
        Assert.Contains("signer", context.Principal!.GetAudiences());

        Assert.Contains(authSink.Events, record => record.EventType == "authority.client_credentials.grant" && record.Outcome == AuthEventOutcome.Success);

        var identityProviderClaim = context.Principal?.GetClaim(StellaOpsClaimTypes.IdentityProvider);
        Assert.Equal(clientDocument.Plugin, identityProviderClaim);

        var principal = context.Principal ?? throw new InvalidOperationException("Principal missing");
        Assert.Equal("tenant-alpha", principal.FindFirstValue(StellaOpsClaimTypes.Tenant));
        var tokenId = principal.GetClaim(OpenIddictConstants.Claims.JwtId);
        Assert.False(string.IsNullOrWhiteSpace(tokenId));

        var signInContext = new OpenIddictServerEvents.ProcessSignInContext(transaction)
        {
            Principal = principal,
            AccessTokenPrincipal = principal
        };

        await persistHandler.HandleAsync(signInContext);

        var persisted = Assert.IsType<AuthorityTokenDocument>(tokenStore.Inserted);
        Assert.Equal(tokenId, persisted.TokenId);
        Assert.Equal(clientDocument.ClientId, persisted.ClientId);
        Assert.Equal("valid", persisted.Status);
        Assert.Equal("tenant-alpha", persisted.Tenant);
        Assert.Equal(new[] { "jobs:trigger" }, persisted.Scope);
    }
}

public class TokenValidationHandlersTests
{
    private static readonly ActivitySource TestActivitySource = new("StellaOps.Authority.Tests.TokenValidation");

    [Fact]
    public async Task ValidateAccessTokenHandler_Rejects_WhenTokenRevoked()
    {
        var tokenStore = new TestTokenStore();
        tokenStore.Inserted = new AuthorityTokenDocument
        {
            TokenId = "token-1",
            Status = "revoked",
            ClientId = "concelier"
        };

        var metadataAccessor = new TestRateLimiterMetadataAccessor();
        var auditSink = new TestAuthEventSink();
        var sessionAccessor = new NullMongoSessionAccessor();
        var handler = new ValidateAccessTokenHandler(
            tokenStore,
            sessionAccessor,
            new TestClientStore(CreateClient()),
            CreateRegistry(withClientProvisioning: true, clientDescriptor: CreateDescriptor(CreateClient())),
            metadataAccessor,
            auditSink,
            TimeProvider.System,
            TestActivitySource,
            NullLogger<ValidateAccessTokenHandler>.Instance);

        var transaction = new OpenIddictServerTransaction
        {
            Options = new OpenIddictServerOptions(),
            EndpointType = OpenIddictServerEndpointType.Token,
            Request = new OpenIddictRequest()
        };

        var principal = CreatePrincipal("concelier", "token-1", "standard");
        var context = new OpenIddictServerEvents.ValidateTokenContext(transaction)
        {
            Principal = principal,
            TokenId = "token-1"
        };

        await handler.HandleAsync(context);

        Assert.True(context.IsRejected);
        Assert.Equal(OpenIddictConstants.Errors.InvalidToken, context.Error);
    }

    [Fact]
    public async Task ValidateAccessTokenHandler_EnrichesClaims_WhenProviderAvailable()
    {
        var clientDocument = CreateClient();
        var userDescriptor = new AuthorityUserDescriptor("user-1", "alice", displayName: "Alice", requiresPasswordReset: false);

        var plugin = CreatePlugin(
            name: "standard",
            supportsClientProvisioning: true,
            descriptor: CreateDescriptor(clientDocument),
            user: userDescriptor);

        var registry = CreateRegistryFromPlugins(plugin);

        var metadataAccessorSuccess = new TestRateLimiterMetadataAccessor();
        var auditSinkSuccess = new TestAuthEventSink();
        var sessionAccessor = new NullMongoSessionAccessor();
        var handler = new ValidateAccessTokenHandler(
            new TestTokenStore(),
            sessionAccessor,
            new TestClientStore(clientDocument),
            registry,
            metadataAccessorSuccess,
            auditSinkSuccess,
            TimeProvider.System,
            TestActivitySource,
            NullLogger<ValidateAccessTokenHandler>.Instance);

        var transaction = new OpenIddictServerTransaction
        {
            Options = new OpenIddictServerOptions(),
            EndpointType = OpenIddictServerEndpointType.Token,
            Request = new OpenIddictRequest()
        };

        var principal = CreatePrincipal(clientDocument.ClientId, "token-123", plugin.Name, subject: userDescriptor.SubjectId);
        var context = new OpenIddictServerEvents.ValidateTokenContext(transaction)
        {
            Principal = principal
        };

        await handler.HandleAsync(context);

        Assert.False(context.IsRejected);
        Assert.Contains(principal.Claims, claim => claim.Type == "enriched" && claim.Value == "true");
    }

    [Fact]
    public async Task ValidateAccessTokenHandler_AddsConfirmationClaim_ForMtlsToken()
    {
        var tokenDocument = new AuthorityTokenDocument
        {
            TokenId = "token-mtls",
            Status = "valid",
            ClientId = "mtls-client",
            SenderConstraint = AuthoritySenderConstraintKinds.Mtls,
            SenderKeyThumbprint = "thumb-print"
        };

        var tokenStore = new TestTokenStore
        {
            Inserted = tokenDocument
        };

        var clientDocument = CreateClient();
        var registry = CreateRegistry(withClientProvisioning: false, clientDescriptor: null);
        var metadataAccessor = new TestRateLimiterMetadataAccessor();
        var auditSink = new TestAuthEventSink();
        var sessionAccessor = new NullMongoSessionAccessor();
        var handler = new ValidateAccessTokenHandler(
            tokenStore,
            sessionAccessor,
            new TestClientStore(clientDocument),
            registry,
            metadataAccessor,
            auditSink,
            TimeProvider.System,
            TestActivitySource,
            NullLogger<ValidateAccessTokenHandler>.Instance);

        var transaction = new OpenIddictServerTransaction
        {
            Options = new OpenIddictServerOptions(),
            EndpointType = OpenIddictServerEndpointType.Introspection,
            Request = new OpenIddictRequest()
        };

        var principal = CreatePrincipal(clientDocument.ClientId, tokenDocument.TokenId, clientDocument.Plugin);
        var context = new OpenIddictServerEvents.ValidateTokenContext(transaction)
        {
            Principal = principal,
            TokenId = tokenDocument.TokenId
        };

        await handler.HandleAsync(context);

        Assert.False(context.IsRejected);
        var confirmation = context.Principal?.GetClaim(AuthorityOpenIddictConstants.ConfirmationClaimType);
        Assert.False(string.IsNullOrWhiteSpace(confirmation));
        using var json = JsonDocument.Parse(confirmation!);
        Assert.Equal(tokenDocument.SenderKeyThumbprint, json.RootElement.GetProperty("x5t#S256").GetString());
    }

    [Fact]
    public async Task ValidateAccessTokenHandler_EmitsReplayAudit_WhenStoreDetectsSuspectedReplay()
    {
        var tokenStore = new TestTokenStore();
        tokenStore.Inserted = new AuthorityTokenDocument
        {
            TokenId = "token-replay",
            Status = "valid",
            ClientId = "agent",
            Devices = new List<BsonDocument>
            {
                new BsonDocument
                {
                    { "remoteAddress", "10.0.0.1" },
                    { "userAgent", "agent/1.0" },
                    { "firstSeen", BsonDateTime.Create(DateTimeOffset.UtcNow.AddMinutes(-15)) },
                    { "lastSeen", BsonDateTime.Create(DateTimeOffset.UtcNow.AddMinutes(-5)) },
                    { "useCount", 2 }
                }
            }
        };

        tokenStore.UsageCallback = (remote, agent) => new TokenUsageUpdateResult(TokenUsageUpdateStatus.SuspectedReplay, remote, agent);

        var metadataAccessor = new TestRateLimiterMetadataAccessor();
        var metadata = metadataAccessor.GetMetadata();
        if (metadata is not null)
        {
            metadata.RemoteIp = "203.0.113.7";
            metadata.UserAgent = "agent/2.0";
        }

        var clientDocument = CreateClient();
        clientDocument.ClientId = "agent";
        var auditSink = new TestAuthEventSink();
        var registry = CreateRegistry(withClientProvisioning: false, clientDescriptor: null);
        var sessionAccessorReplay = new NullMongoSessionAccessor();
        var handler = new ValidateAccessTokenHandler(
            tokenStore,
            sessionAccessorReplay,
            new TestClientStore(clientDocument),
            registry,
            metadataAccessor,
            auditSink,
            TimeProvider.System,
            TestActivitySource,
            NullLogger<ValidateAccessTokenHandler>.Instance);

        var transaction = new OpenIddictServerTransaction
        {
            Options = new OpenIddictServerOptions(),
            EndpointType = OpenIddictServerEndpointType.Introspection,
            Request = new OpenIddictRequest()
        };

        var principal = CreatePrincipal("agent", "token-replay", "standard");
        var context = new OpenIddictServerEvents.ValidateTokenContext(transaction)
        {
            Principal = principal,
            TokenId = "token-replay"
        };

        await handler.HandleAsync(context);

        Assert.False(context.IsRejected);
        var replayEvent = Assert.Single(auditSink.Events, record => record.EventType == "authority.token.replay.suspected");
        Assert.Equal(AuthEventOutcome.Error, replayEvent.Outcome);
        Assert.NotNull(replayEvent.Network);
        Assert.Equal("203.0.113.7", replayEvent.Network?.RemoteAddress.Value);
        Assert.Contains(replayEvent.Properties, property => property.Name == "token.devices.total");
    }
}

public class AuthorityClientCertificateValidatorTests
{
    [Fact]
    public async Task ValidateAsync_Rejects_WhenSanTypeNotAllowed()
    {
        var options = new StellaOpsAuthorityOptions
        {
            Issuer = new Uri("https://authority.test")
        };
        options.Security.SenderConstraints.Mtls.Enabled = true;
        options.Security.SenderConstraints.Mtls.RequireChainValidation = false;
        options.Security.SenderConstraints.Mtls.AllowedSanTypes.Clear();
        options.Security.SenderConstraints.Mtls.AllowedSanTypes.Add("uri");
        options.Signing.ActiveKeyId = "test-key";
        options.Signing.KeyPath = "/tmp/test-key.pem";
        options.Storage.ConnectionString = "mongodb://localhost/test";

        using var rsa = RSA.Create(2048);
        var request = new CertificateRequest("CN=mtls-client", rsa, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
        var sanBuilder = new SubjectAlternativeNameBuilder();
        sanBuilder.AddDnsName("client.mtls.test");
        request.CertificateExtensions.Add(sanBuilder.Build());
        using var certificate = request.CreateSelfSigned(DateTimeOffset.UtcNow.AddMinutes(-5), DateTimeOffset.UtcNow.AddMinutes(5));

        var clientDocument = CreateClient();
        clientDocument.SenderConstraint = AuthoritySenderConstraintKinds.Mtls;
        clientDocument.CertificateBindings.Add(new AuthorityClientCertificateBinding
        {
            Thumbprint = Convert.ToHexString(certificate.GetCertHash(HashAlgorithmName.SHA256))
        });

        var httpContext = new DefaultHttpContext();
        httpContext.Connection.ClientCertificate = certificate;

        var validator = new AuthorityClientCertificateValidator(options, TimeProvider.System, NullLogger<AuthorityClientCertificateValidator>.Instance);
        var result = await validator.ValidateAsync(httpContext, clientDocument, CancellationToken.None);

        Assert.False(result.Succeeded);
        Assert.Equal("certificate_san_type", result.Error);
    }

    [Fact]
    public async Task ValidateAsync_AllowsBindingWithinRotationGrace()
    {
        var options = new StellaOpsAuthorityOptions
        {
            Issuer = new Uri("https://authority.test")
        };
        options.Security.SenderConstraints.Mtls.Enabled = true;
        options.Security.SenderConstraints.Mtls.RequireChainValidation = false;
        options.Security.SenderConstraints.Mtls.RotationGrace = TimeSpan.FromMinutes(5);
        options.Signing.ActiveKeyId = "test-key";
        options.Signing.KeyPath = "/tmp/test-key.pem";
        options.Storage.ConnectionString = "mongodb://localhost/test";

        using var rsa = RSA.Create(2048);
        var request = new CertificateRequest("CN=mtls-client", rsa, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
        var sanBuilder = new SubjectAlternativeNameBuilder();
        sanBuilder.AddDnsName("client.mtls.test");
        request.CertificateExtensions.Add(sanBuilder.Build());
        using var certificate = request.CreateSelfSigned(DateTimeOffset.UtcNow.AddMinutes(-5), DateTimeOffset.UtcNow.AddMinutes(10));

        var thumbprint = Convert.ToHexString(certificate.GetCertHash(HashAlgorithmName.SHA256));

        var clientDocument = CreateClient();
        clientDocument.SenderConstraint = AuthoritySenderConstraintKinds.Mtls;
        clientDocument.CertificateBindings.Add(new AuthorityClientCertificateBinding
        {
            Thumbprint = thumbprint,
            NotBefore = TimeProvider.System.GetUtcNow().AddMinutes(2)
        });

        var httpContext = new DefaultHttpContext();
        httpContext.Connection.ClientCertificate = certificate;

        var validator = new AuthorityClientCertificateValidator(options, TimeProvider.System, NullLogger<AuthorityClientCertificateValidator>.Instance);
        var result = await validator.ValidateAsync(httpContext, clientDocument, CancellationToken.None);

        Assert.True(result.Succeeded);
        Assert.Equal(thumbprint, result.HexThumbprint);
    }

    [Fact]
    public async Task ValidateAsync_Rejects_WhenBindingSubjectMismatch()
    {
        var options = new StellaOpsAuthorityOptions
        {
            Issuer = new Uri("https://authority.test")
        };
        options.Security.SenderConstraints.Mtls.Enabled = true;
        options.Security.SenderConstraints.Mtls.RequireChainValidation = false;
        options.Signing.ActiveKeyId = "test-key";
        options.Signing.KeyPath = "/tmp/test-key.pem";
        options.Storage.ConnectionString = "mongodb://localhost/test";

        using var rsa = RSA.Create(2048);
        var request = new CertificateRequest("CN=mtls-client", rsa, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
        var sanBuilder = new SubjectAlternativeNameBuilder();
        sanBuilder.AddDnsName("client.mtls.test");
        request.CertificateExtensions.Add(sanBuilder.Build());
        using var certificate = request.CreateSelfSigned(DateTimeOffset.UtcNow.AddMinutes(-5), DateTimeOffset.UtcNow.AddMinutes(5));

        var clientDocument = CreateClient();
        clientDocument.SenderConstraint = AuthoritySenderConstraintKinds.Mtls;
        clientDocument.CertificateBindings.Add(new AuthorityClientCertificateBinding
        {
            Thumbprint = Convert.ToHexString(certificate.GetCertHash(HashAlgorithmName.SHA256)),
            Subject = "CN=different-client"
        });

        var httpContext = new DefaultHttpContext();
        httpContext.Connection.ClientCertificate = certificate;

        var validator = new AuthorityClientCertificateValidator(options, TimeProvider.System, NullLogger<AuthorityClientCertificateValidator>.Instance);
        var result = await validator.ValidateAsync(httpContext, clientDocument, CancellationToken.None);

        Assert.False(result.Succeeded);
        Assert.Equal("certificate_binding_subject_mismatch", result.Error);
    }

    [Fact]
    public async Task ValidateAsync_Rejects_WhenBindingSansMissing()
    {
        var options = new StellaOpsAuthorityOptions
        {
            Issuer = new Uri("https://authority.test")
        };
        options.Security.SenderConstraints.Mtls.Enabled = true;
        options.Security.SenderConstraints.Mtls.RequireChainValidation = false;
        options.Signing.ActiveKeyId = "test-key";
        options.Signing.KeyPath = "/tmp/test-key.pem";
        options.Storage.ConnectionString = "mongodb://localhost/test";

        using var rsa = RSA.Create(2048);
        var request = new CertificateRequest("CN=mtls-client", rsa, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
        var sanBuilder = new SubjectAlternativeNameBuilder();
        sanBuilder.AddDnsName("client.mtls.test");
        request.CertificateExtensions.Add(sanBuilder.Build());
        using var certificate = request.CreateSelfSigned(DateTimeOffset.UtcNow.AddMinutes(-5), DateTimeOffset.UtcNow.AddMinutes(5));

        var clientDocument = CreateClient();
        clientDocument.SenderConstraint = AuthoritySenderConstraintKinds.Mtls;
        clientDocument.CertificateBindings.Add(new AuthorityClientCertificateBinding
        {
            Thumbprint = Convert.ToHexString(certificate.GetCertHash(HashAlgorithmName.SHA256)),
            SubjectAlternativeNames = new List<string> { "spiffe://client" }
        });

        var httpContext = new DefaultHttpContext();
        httpContext.Connection.ClientCertificate = certificate;

        var validator = new AuthorityClientCertificateValidator(options, TimeProvider.System, NullLogger<AuthorityClientCertificateValidator>.Instance);
        var result = await validator.ValidateAsync(httpContext, clientDocument, CancellationToken.None);

        Assert.False(result.Succeeded);
        Assert.Equal("certificate_binding_san_mismatch", result.Error);
    }
}

internal sealed class TestClientStore : IAuthorityClientStore
{
    private readonly Dictionary<string, AuthorityClientDocument> clients = new(StringComparer.OrdinalIgnoreCase);

    public TestClientStore(params AuthorityClientDocument[] documents)
    {
        foreach (var document in documents)
        {
            clients[document.ClientId] = document;
        }
    }

    public ValueTask<AuthorityClientDocument?> FindByClientIdAsync(string clientId, CancellationToken cancellationToken, IClientSessionHandle? session = null)
    {
        clients.TryGetValue(clientId, out var document);
        return ValueTask.FromResult(document);
    }

    public ValueTask UpsertAsync(AuthorityClientDocument document, CancellationToken cancellationToken, IClientSessionHandle? session = null)
    {
        clients[document.ClientId] = document;
        return ValueTask.CompletedTask;
    }

    public ValueTask<bool> DeleteByClientIdAsync(string clientId, CancellationToken cancellationToken, IClientSessionHandle? session = null)
        => ValueTask.FromResult(clients.Remove(clientId));
}

internal sealed class TestTokenStore : IAuthorityTokenStore
{
    public AuthorityTokenDocument? Inserted { get; set; }

    public Func<string?, string?, TokenUsageUpdateResult>? UsageCallback { get; set; }

    public ValueTask InsertAsync(AuthorityTokenDocument document, CancellationToken cancellationToken, IClientSessionHandle? session = null)
    {
        Inserted = document;
        return ValueTask.CompletedTask;
    }

    public ValueTask<AuthorityTokenDocument?> FindByTokenIdAsync(string tokenId, CancellationToken cancellationToken, IClientSessionHandle? session = null)
        => ValueTask.FromResult(Inserted is not null && string.Equals(Inserted.TokenId, tokenId, StringComparison.OrdinalIgnoreCase) ? Inserted : null);

    public ValueTask<AuthorityTokenDocument?> FindByReferenceIdAsync(string referenceId, CancellationToken cancellationToken, IClientSessionHandle? session = null)
        => ValueTask.FromResult<AuthorityTokenDocument?>(null);

    public ValueTask UpdateStatusAsync(string tokenId, string status, DateTimeOffset? revokedAt, string? reason, string? reasonDescription, IReadOnlyDictionary<string, string?>? metadata, CancellationToken cancellationToken, IClientSessionHandle? session = null)
        => ValueTask.CompletedTask;

    public ValueTask<long> DeleteExpiredAsync(DateTimeOffset threshold, CancellationToken cancellationToken, IClientSessionHandle? session = null)
        => ValueTask.FromResult(0L);

    public ValueTask<TokenUsageUpdateResult> RecordUsageAsync(string tokenId, string? remoteAddress, string? userAgent, DateTimeOffset observedAt, CancellationToken cancellationToken, IClientSessionHandle? session = null)
        => ValueTask.FromResult(UsageCallback?.Invoke(remoteAddress, userAgent) ?? new TokenUsageUpdateResult(TokenUsageUpdateStatus.Recorded, remoteAddress, userAgent));

    public ValueTask<IReadOnlyList<AuthorityTokenDocument>> ListRevokedAsync(DateTimeOffset? issuedAfter, CancellationToken cancellationToken, IClientSessionHandle? session = null)
        => ValueTask.FromResult<IReadOnlyList<AuthorityTokenDocument>>(Array.Empty<AuthorityTokenDocument>());
}

internal sealed class TestClaimsEnricher : IClaimsEnricher
{
    public ValueTask EnrichAsync(ClaimsIdentity identity, AuthorityClaimsEnrichmentContext context, CancellationToken cancellationToken)
    {
        if (!identity.HasClaim(c => c.Type == "enriched"))
        {
            identity.AddClaim(new Claim("enriched", "true"));
        }

        return ValueTask.CompletedTask;
    }
}

internal sealed class TestUserCredentialStore : IUserCredentialStore
{
    private readonly AuthorityUserDescriptor? user;

    public TestUserCredentialStore(AuthorityUserDescriptor? user)
    {
        this.user = user;
    }

    public ValueTask<AuthorityCredentialVerificationResult> VerifyPasswordAsync(string username, string password, CancellationToken cancellationToken)
        => ValueTask.FromResult(AuthorityCredentialVerificationResult.Failure(AuthorityCredentialFailureCode.InvalidCredentials));

    public ValueTask<AuthorityPluginOperationResult<AuthorityUserDescriptor>> UpsertUserAsync(AuthorityUserRegistration registration, CancellationToken cancellationToken)
        => ValueTask.FromResult(AuthorityPluginOperationResult<AuthorityUserDescriptor>.Failure("unsupported", "not implemented"));

    public ValueTask<AuthorityUserDescriptor?> FindBySubjectAsync(string subjectId, CancellationToken cancellationToken)
        => ValueTask.FromResult(user);
}

internal sealed class TestClientProvisioningStore : IClientProvisioningStore
{
    private readonly AuthorityClientDescriptor? descriptor;

    public TestClientProvisioningStore(AuthorityClientDescriptor? descriptor)
    {
        this.descriptor = descriptor;
    }

    public ValueTask<AuthorityPluginOperationResult<AuthorityClientDescriptor>> CreateOrUpdateAsync(AuthorityClientRegistration registration, CancellationToken cancellationToken)
        => ValueTask.FromResult(AuthorityPluginOperationResult<AuthorityClientDescriptor>.Failure("unsupported", "not implemented"));

    public ValueTask<AuthorityClientDescriptor?> FindByClientIdAsync(string clientId, CancellationToken cancellationToken)
        => ValueTask.FromResult(descriptor);

    public ValueTask<AuthorityPluginOperationResult> DeleteAsync(string clientId, CancellationToken cancellationToken)
        => ValueTask.FromResult(AuthorityPluginOperationResult.Success());
}

internal sealed class TestIdentityProviderPlugin : IIdentityProviderPlugin
{
    public TestIdentityProviderPlugin(
        AuthorityPluginContext context,
        IUserCredentialStore credentialStore,
        IClaimsEnricher claimsEnricher,
        IClientProvisioningStore? clientProvisioning,
        AuthorityIdentityProviderCapabilities capabilities)
    {
        Context = context;
        Credentials = credentialStore;
        ClaimsEnricher = claimsEnricher;
        ClientProvisioning = clientProvisioning;
        Capabilities = capabilities;
    }

    public string Name => Context.Manifest.Name;

    public string Type => Context.Manifest.Type;

    public AuthorityPluginContext Context { get; }

    public IUserCredentialStore Credentials { get; }

    public IClaimsEnricher ClaimsEnricher { get; }

    public IClientProvisioningStore? ClientProvisioning { get; }

    public AuthorityIdentityProviderCapabilities Capabilities { get; }

    public ValueTask<AuthorityPluginHealthResult> CheckHealthAsync(CancellationToken cancellationToken)
        => ValueTask.FromResult(AuthorityPluginHealthResult.Healthy());
}

internal sealed class TestAuthEventSink : IAuthEventSink
{
    public List<AuthEventRecord> Events { get; } = new();

    public ValueTask WriteAsync(AuthEventRecord record, CancellationToken cancellationToken)
    {
        Events.Add(record);
        return ValueTask.CompletedTask;
    }
}

internal sealed class TestRateLimiterMetadataAccessor : IAuthorityRateLimiterMetadataAccessor
{
    private readonly AuthorityRateLimiterMetadata metadata = new();

    public AuthorityRateLimiterMetadata? GetMetadata() => metadata;

    public void SetClientId(string? clientId) => metadata.ClientId = clientId;

    public void SetSubjectId(string? subjectId) => metadata.SubjectId = subjectId;

    public void SetTenant(string? tenant)
    {
        metadata.Tenant = string.IsNullOrWhiteSpace(tenant) ? null : tenant.Trim().ToLowerInvariant();
        metadata.SetTag("authority.tenant", metadata.Tenant);
    }

    public void SetTag(string name, string? value) => metadata.SetTag(name, value);
}

internal sealed class NoopCertificateValidator : IAuthorityClientCertificateValidator
{
    public ValueTask<AuthorityClientCertificateValidationResult> ValidateAsync(HttpContext httpContext, AuthorityClientDocument client, CancellationToken cancellationToken)
    {
        var binding = new AuthorityClientCertificateBinding
        {
            Thumbprint = "stub"
        };

        return ValueTask.FromResult(AuthorityClientCertificateValidationResult.Success("stub", "stub", binding));
    }
}

internal sealed class RecordingCertificateValidator : IAuthorityClientCertificateValidator
{
    public bool Invoked { get; private set; }

    public ValueTask<AuthorityClientCertificateValidationResult> ValidateAsync(HttpContext httpContext, AuthorityClientDocument client, CancellationToken cancellationToken)
    {
        Invoked = true;

        if (httpContext.Connection.ClientCertificate is null)
        {
            return ValueTask.FromResult(AuthorityClientCertificateValidationResult.Failure("client_certificate_required"));
        }

        AuthorityClientCertificateBinding binding;
        if (client.CertificateBindings.Count > 0)
        {
            binding = client.CertificateBindings[0];
        }
        else
        {
            binding = new AuthorityClientCertificateBinding { Thumbprint = "stub" };
        }

        return ValueTask.FromResult(AuthorityClientCertificateValidationResult.Success("stub", binding.Thumbprint, binding));
    }
}

internal sealed class NullMongoSessionAccessor : IAuthorityMongoSessionAccessor
{
    public ValueTask<IClientSessionHandle> GetSessionAsync(CancellationToken cancellationToken = default)
        => ValueTask.FromResult<IClientSessionHandle>(null!);

    public ValueTask DisposeAsync() => ValueTask.CompletedTask;
}

internal static class TestHelpers
{
    public static StellaOpsAuthorityOptions CreateAuthorityOptions(Action<StellaOpsAuthorityOptions>? configure = null)
    {
        var options = new StellaOpsAuthorityOptions
        {
            Issuer = new Uri("https://authority.test")
        };

        options.Signing.ActiveKeyId = "test-key";
        options.Signing.KeyPath = "/tmp/test-key.pem";
        options.Storage.ConnectionString = "mongodb://localhost/test";

        configure?.Invoke(options);
        return options;
    }

    public static AuthorityClientDocument CreateClient(
        string clientId = "concelier",
        string? secret = "s3cr3t!",
        string clientType = "confidential",
        string allowedGrantTypes = "client_credentials",
        string allowedScopes = "jobs:read",
        string allowedAudiences = "",
        string? tenant = null)
    {
        var document = new AuthorityClientDocument
        {
            ClientId = clientId,
            ClientType = clientType,
            SecretHash = secret is null ? null : AuthoritySecretHasher.ComputeHash(secret),
            Plugin = "standard",
            Properties = new Dictionary<string, string?>(StringComparer.OrdinalIgnoreCase)
            {
                [AuthorityClientMetadataKeys.AllowedGrantTypes] = allowedGrantTypes,
                [AuthorityClientMetadataKeys.AllowedScopes] = allowedScopes
            }
        };

        if (!string.IsNullOrWhiteSpace(allowedAudiences))
        {
            document.Properties[AuthorityClientMetadataKeys.Audiences] = allowedAudiences;
        }

        var normalizedTenant = NormalizeTenant(tenant);
        if (normalizedTenant is not null)
        {
            document.Properties[AuthorityClientMetadataKeys.Tenant] = normalizedTenant;
        }

        return document;
    }

    private static string? NormalizeTenant(string? value)
        => string.IsNullOrWhiteSpace(value) ? null : value.Trim().ToLowerInvariant();

    public static AuthorityClientDescriptor CreateDescriptor(AuthorityClientDocument document)
    {
        var allowedGrantTypes = document.Properties.TryGetValue(AuthorityClientMetadataKeys.AllowedGrantTypes, out var grants) ? grants?.Split(' ', StringSplitOptions.RemoveEmptyEntries) : Array.Empty<string>();
        var allowedScopes = document.Properties.TryGetValue(AuthorityClientMetadataKeys.AllowedScopes, out var scopes) ? scopes?.Split(' ', StringSplitOptions.RemoveEmptyEntries) : Array.Empty<string>();
        var allowedAudiences = document.Properties.TryGetValue(AuthorityClientMetadataKeys.Audiences, out var audiences) ? audiences?.Split(' ', StringSplitOptions.RemoveEmptyEntries) : Array.Empty<string>();

        return new AuthorityClientDescriptor(
            document.ClientId,
            document.DisplayName,
            confidential: string.Equals(document.ClientType, "confidential", StringComparison.OrdinalIgnoreCase),
            allowedGrantTypes,
            allowedScopes,
            allowedAudiences,
            redirectUris: Array.Empty<Uri>(),
            postLogoutRedirectUris: Array.Empty<Uri>(),
            properties: document.Properties);
    }

    public static AuthorityIdentityProviderRegistry CreateRegistry(bool withClientProvisioning, AuthorityClientDescriptor? clientDescriptor)
    {
        var plugin = CreatePlugin(
            name: "standard",
            supportsClientProvisioning: withClientProvisioning,
            descriptor: clientDescriptor,
            user: null);

        return CreateRegistryFromPlugins(plugin);
    }

    public static TestIdentityProviderPlugin CreatePlugin(
        string name,
        bool supportsClientProvisioning,
        AuthorityClientDescriptor? descriptor,
        AuthorityUserDescriptor? user)
    {
        var capabilities = supportsClientProvisioning
            ? new[] { AuthorityPluginCapabilities.ClientProvisioning }
            : Array.Empty<string>();

        var manifest = new AuthorityPluginManifest(
            name,
            "standard",
            true,
            null,
            null,
            capabilities,
            new Dictionary<string, string?>(StringComparer.OrdinalIgnoreCase),
            $"{name}.yaml");

        var context = new AuthorityPluginContext(manifest, new ConfigurationBuilder().Build());

        return new TestIdentityProviderPlugin(
            context,
            new TestUserCredentialStore(user),
            new TestClaimsEnricher(),
            supportsClientProvisioning ? new TestClientProvisioningStore(descriptor) : null,
            new AuthorityIdentityProviderCapabilities(
                SupportsPassword: true,
                SupportsMfa: false,
                SupportsClientProvisioning: supportsClientProvisioning));
    }

    public static AuthorityIdentityProviderRegistry CreateRegistryFromPlugins(params IIdentityProviderPlugin[] plugins)
    {
        var services = new ServiceCollection();
        services.AddLogging();
        foreach (var plugin in plugins)
        {
            services.AddSingleton<IIdentityProviderPlugin>(plugin);
        }

        var provider = services.BuildServiceProvider();
        return new AuthorityIdentityProviderRegistry(provider, NullLogger<AuthorityIdentityProviderRegistry>.Instance);
    }

    public static OpenIddictServerTransaction CreateTokenTransaction(string clientId, string? secret, string? scope)
    {
        var request = new OpenIddictRequest
        {
            GrantType = OpenIddictConstants.GrantTypes.ClientCredentials,
            ClientId = clientId,
            ClientSecret = secret
        };

        if (!string.IsNullOrWhiteSpace(scope))
        {
            request.Scope = scope;
        }

        return new OpenIddictServerTransaction
        {
            EndpointType = OpenIddictServerEndpointType.Token,
            Options = new OpenIddictServerOptions(),
            Request = request
        };
    }

    public static string ConvertThumbprintToString(object thumbprint)
        => thumbprint switch
        {
            string value => value,
            byte[] bytes => Base64UrlEncoder.Encode(bytes),
            _ => throw new InvalidOperationException("Unsupported thumbprint representation.")
        };

    public static string CreateDpopProof(ECDsaSecurityKey key, string method, string url, long issuedAt, string? nonce = null)
    {
        var jwk = JsonWebKeyConverter.ConvertFromECDsaSecurityKey(key);
        jwk.KeyId ??= key.KeyId ?? Guid.NewGuid().ToString("N");

        var signingCredentials = new SigningCredentials(key, SecurityAlgorithms.EcdsaSha256);
        var header = new JwtHeader(signingCredentials)
        {
            ["typ"] = "dpop+jwt",
            ["jwk"] = new Dictionary<string, object?>
            {
                ["kty"] = jwk.Kty,
                ["crv"] = jwk.Crv,
                ["x"] = jwk.X,
                ["y"] = jwk.Y,
                ["kid"] = jwk.Kid ?? jwk.KeyId
            }
        };

        var payload = new JwtPayload
        {
            ["htm"] = method.ToUpperInvariant(),
            ["htu"] = url,
            ["iat"] = issuedAt,
            ["jti"] = Guid.NewGuid().ToString("N")
        };

        if (!string.IsNullOrWhiteSpace(nonce))
        {
            payload["nonce"] = nonce;
        }

        var token = new JwtSecurityToken(header, payload);
        return new JwtSecurityTokenHandler().WriteToken(token);
    }

    public static X509Certificate2 CreateTestCertificate(string subjectName)
    {
        using var rsa = RSA.Create(2048);
        var request = new CertificateRequest(subjectName, rsa, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
        return request.CreateSelfSigned(DateTimeOffset.UtcNow.AddMinutes(-5), DateTimeOffset.UtcNow.AddHours(1));
    }

    public static ClaimsPrincipal CreatePrincipal(string clientId, string tokenId, string provider, string? subject = null)
    {
        var identity = new ClaimsIdentity(OpenIddictServerAspNetCoreDefaults.AuthenticationScheme);
        identity.AddClaim(new Claim(OpenIddictConstants.Claims.ClientId, clientId));
        identity.AddClaim(new Claim(OpenIddictConstants.Claims.JwtId, tokenId));
        identity.AddClaim(new Claim(StellaOpsClaimTypes.IdentityProvider, provider));

        if (!string.IsNullOrWhiteSpace(subject))
        {
            identity.AddClaim(new Claim(OpenIddictConstants.Claims.Subject, subject));
        }

        return new ClaimsPrincipal(identity);
    }
}