using System;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using StellaOps.Attestor.Core.Options;
using StellaOps.Attestor.Core.Submission;
using StellaOps.Attestor.Core.Observability;
using StellaOps.Attestor.Infrastructure.Rekor;
using StellaOps.Attestor.Infrastructure.Storage;
using StellaOps.Attestor.Infrastructure.Submission;
using Xunit;

namespace StellaOps.Attestor.Tests;

public sealed class AttestorSubmissionServiceTests
{
    [Fact]
    public async Task SubmitAsync_ReturnsDeterministicUuid_OnDuplicateBundle()
    {
        var options = Options.Create(new AttestorOptions
        {
            Redis = new AttestorOptions.RedisOptions
            {
                Url = string.Empty
            },
            Rekor = new AttestorOptions.RekorOptions
            {
                Primary = new AttestorOptions.RekorBackendOptions
                {
                    Url = "https://rekor.stellaops.test",
                    ProofTimeoutMs = 1000,
                    PollIntervalMs = 50,
                    MaxAttempts = 2
                }
            }
        });

        var canonicalizer = new DefaultDsseCanonicalizer();
        var validator = new AttestorSubmissionValidator(canonicalizer);
        var repository = new InMemoryAttestorEntryRepository();
        var dedupeStore = new InMemoryAttestorDedupeStore();
        var rekorClient = new StubRekorClient(new NullLogger<StubRekorClient>());
        var archiveStore = new NullAttestorArchiveStore(new NullLogger<NullAttestorArchiveStore>());
        var auditSink = new InMemoryAttestorAuditSink();
        var logger = new NullLogger<AttestorSubmissionService>();
        using var metrics = new AttestorMetrics();
        var service = new AttestorSubmissionService(
            validator,
            repository,
            dedupeStore,
            rekorClient,
            archiveStore,
            auditSink,
            options,
            logger,
            TimeProvider.System,
            metrics);

        var request = CreateValidRequest(canonicalizer);
        var context = new SubmissionContext
        {
            CallerSubject = "urn:stellaops:signer",
            CallerAudience = "attestor",
            CallerClientId = "signer-service",
            CallerTenant = "default",
            ClientCertificate = null,
            MtlsThumbprint = "00"
        };

        var first = await service.SubmitAsync(request, context);
        var second = await service.SubmitAsync(request, context);

        Assert.NotNull(first.Uuid);
        Assert.Equal(first.Uuid, second.Uuid);

        var stored = await repository.GetByBundleShaAsync(request.Meta.BundleSha256);
        Assert.NotNull(stored);
        Assert.Equal(first.Uuid, stored!.RekorUuid);
    }

    [Fact]
    public async Task Validator_ThrowsWhenModeNotAllowed()
    {
        var canonicalizer = new DefaultDsseCanonicalizer();
        var validator = new AttestorSubmissionValidator(canonicalizer, new[] { "kms" });

        var request = CreateValidRequest(canonicalizer);
        request.Bundle.Mode = "keyless";

        await Assert.ThrowsAsync<AttestorValidationException>(() => validator.ValidateAsync(request));
    }

    [Fact]
    public async Task SubmitAsync_Throws_WhenMirrorDisabledButRequested()
    {
        var options = Options.Create(new AttestorOptions
        {
            Redis = new AttestorOptions.RedisOptions { Url = string.Empty },
            Rekor = new AttestorOptions.RekorOptions
            {
                Primary = new AttestorOptions.RekorBackendOptions
                {
                    Url = "https://rekor.primary.test",
                    ProofTimeoutMs = 1000,
                    PollIntervalMs = 50,
                    MaxAttempts = 2
                }
            }
        });

        var canonicalizer = new DefaultDsseCanonicalizer();
        var validator = new AttestorSubmissionValidator(canonicalizer);
        var repository = new InMemoryAttestorEntryRepository();
        var dedupeStore = new InMemoryAttestorDedupeStore();
        var rekorClient = new StubRekorClient(new NullLogger<StubRekorClient>());
        var archiveStore = new NullAttestorArchiveStore(new NullLogger<NullAttestorArchiveStore>());
        var auditSink = new InMemoryAttestorAuditSink();
        var logger = new NullLogger<AttestorSubmissionService>();
        using var metrics = new AttestorMetrics();

        var service = new AttestorSubmissionService(
            validator,
            repository,
            dedupeStore,
            rekorClient,
            archiveStore,
            auditSink,
            options,
            logger,
            TimeProvider.System,
            metrics);

        var request = CreateValidRequest(canonicalizer);
        request.Meta.LogPreference = "mirror";

        var context = new SubmissionContext
        {
            CallerSubject = "urn:stellaops:signer",
            CallerAudience = "attestor",
            CallerClientId = "signer-service",
            CallerTenant = "default"
        };

        var ex = await Assert.ThrowsAsync<AttestorValidationException>(() => service.SubmitAsync(request, context));
        Assert.Equal("mirror_disabled", ex.Code);
    }

    [Fact]
    public async Task SubmitAsync_ReturnsMirrorMetadata_WhenPreferenceBoth()
    {
        var options = Options.Create(new AttestorOptions
        {
            Redis = new AttestorOptions.RedisOptions { Url = string.Empty },
            Rekor = new AttestorOptions.RekorOptions
            {
                Primary = new AttestorOptions.RekorBackendOptions
                {
                    Url = "https://rekor.primary.test",
                    ProofTimeoutMs = 1000,
                    PollIntervalMs = 50,
                    MaxAttempts = 2
                },
                Mirror = new AttestorOptions.RekorMirrorOptions
                {
                    Enabled = true,
                    Url = "https://rekor.mirror.test",
                    ProofTimeoutMs = 1000,
                    PollIntervalMs = 50,
                    MaxAttempts = 2
                }
            }
        });

        var canonicalizer = new DefaultDsseCanonicalizer();
        var validator = new AttestorSubmissionValidator(canonicalizer);
        var repository = new InMemoryAttestorEntryRepository();
        var dedupeStore = new InMemoryAttestorDedupeStore();
        var rekorClient = new StubRekorClient(new NullLogger<StubRekorClient>());
        var archiveStore = new NullAttestorArchiveStore(new NullLogger<NullAttestorArchiveStore>());
        var auditSink = new InMemoryAttestorAuditSink();
        var logger = new NullLogger<AttestorSubmissionService>();
        using var metrics = new AttestorMetrics();

        var service = new AttestorSubmissionService(
            validator,
            repository,
            dedupeStore,
            rekorClient,
            archiveStore,
            auditSink,
            options,
            logger,
            TimeProvider.System,
            metrics);

        var request = CreateValidRequest(canonicalizer);
        request.Meta.LogPreference = "both";

        var context = new SubmissionContext
        {
            CallerSubject = "urn:stellaops:signer",
            CallerAudience = "attestor",
            CallerClientId = "signer-service",
            CallerTenant = "default"
        };

        var result = await service.SubmitAsync(request, context);

        Assert.NotNull(result.Mirror);
        Assert.False(string.IsNullOrEmpty(result.Mirror!.Uuid));
        Assert.Equal("included", result.Mirror.Status);
    }

    [Fact]
    public async Task SubmitAsync_UsesMirrorAsCanonical_WhenPreferenceMirror()
    {
        var options = Options.Create(new AttestorOptions
        {
            Redis = new AttestorOptions.RedisOptions { Url = string.Empty },
            Rekor = new AttestorOptions.RekorOptions
            {
                Primary = new AttestorOptions.RekorBackendOptions
                {
                    Url = "https://rekor.primary.test",
                    ProofTimeoutMs = 1000,
                    PollIntervalMs = 50,
                    MaxAttempts = 2
                },
                Mirror = new AttestorOptions.RekorMirrorOptions
                {
                    Enabled = true,
                    Url = "https://rekor.mirror.test",
                    ProofTimeoutMs = 1000,
                    PollIntervalMs = 50,
                    MaxAttempts = 2
                }
            }
        });

        var canonicalizer = new DefaultDsseCanonicalizer();
        var validator = new AttestorSubmissionValidator(canonicalizer);
        var repository = new InMemoryAttestorEntryRepository();
        var dedupeStore = new InMemoryAttestorDedupeStore();
        var rekorClient = new StubRekorClient(new NullLogger<StubRekorClient>());
        var archiveStore = new NullAttestorArchiveStore(new NullLogger<NullAttestorArchiveStore>());
        var auditSink = new InMemoryAttestorAuditSink();
        var logger = new NullLogger<AttestorSubmissionService>();
        using var metrics = new AttestorMetrics();

        var service = new AttestorSubmissionService(
            validator,
            repository,
            dedupeStore,
            rekorClient,
            archiveStore,
            auditSink,
            options,
            logger,
            TimeProvider.System,
            metrics);

        var request = CreateValidRequest(canonicalizer);
        request.Meta.LogPreference = "mirror";

        var context = new SubmissionContext
        {
            CallerSubject = "urn:stellaops:signer",
            CallerAudience = "attestor",
            CallerClientId = "signer-service",
            CallerTenant = "default"
        };

        var result = await service.SubmitAsync(request, context);

        Assert.NotNull(result.Uuid);
        var stored = await repository.GetByBundleShaAsync(request.Meta.BundleSha256);
        Assert.NotNull(stored);
        Assert.Equal("mirror", stored!.Log.Backend);
        Assert.Null(result.Mirror);
    }

    private static AttestorSubmissionRequest CreateValidRequest(DefaultDsseCanonicalizer canonicalizer)
    {
        var request = new AttestorSubmissionRequest
        {
            Bundle = new AttestorSubmissionRequest.SubmissionBundle
            {
                Mode = "keyless",
                Dsse = new AttestorSubmissionRequest.DsseEnvelope
                {
                    PayloadType = "application/vnd.in-toto+json",
                    PayloadBase64 = Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes("{}")),
                    Signatures =
                    {
                        new AttestorSubmissionRequest.DsseSignature
                        {
                            KeyId = "test",
                            Signature = Convert.ToBase64String(RandomNumberGenerator.GetBytes(32))
                        }
                    }
                }
            },
            Meta = new AttestorSubmissionRequest.SubmissionMeta
            {
                Artifact = new AttestorSubmissionRequest.ArtifactInfo
                {
                    Sha256 = new string('a', 64),
                    Kind = "sbom"
                },
                LogPreference = "primary",
                Archive = false
            }
        };

        var canonical = canonicalizer.CanonicalizeAsync(request).GetAwaiter().GetResult();
        request.Meta.BundleSha256 = Convert.ToHexString(SHA256.HashData(canonical)).ToLowerInvariant();
        return request;
    }
}