// <copyright file="FacetSealIntegrationTests.cs" company="StellaOps">
// Copyright (c) StellaOps. Licensed under BUSL-1.1.
// </copyright>

// -----------------------------------------------------------------------------
// FacetSealIntegrationTests.cs
// Sprint: SPRINT_20260105_002_002_FACET
// Task: FCT-020 - Integration tests: Extraction from real image layers
// Description: Integration tests for facet seal extraction from tar and OCI layers.
// -----------------------------------------------------------------------------

using System.Formats.Tar;
using System.IO.Compression;
using System.Text;
using FluentAssertions;
using Microsoft.Extensions.Time.Testing;
using StellaOps.Facet;
using Xunit;

namespace StellaOps.Scanner.Surface.FS.Tests;

/// <summary>
/// Integration tests for facet seal extraction from tar and OCI layers.
/// </summary>
[Trait("Category", "Integration")]
public sealed class FacetSealIntegrationTests : IDisposable
{
    private readonly FakeTimeProvider _timeProvider;
    private readonly GlobFacetExtractor _facetExtractor;
    private readonly FacetSealExtractor _sealExtractor;
    private readonly string _testDir;

    public FacetSealIntegrationTests()
    {
        _timeProvider = new FakeTimeProvider(new DateTimeOffset(2026, 1, 6, 12, 0, 0, TimeSpan.Zero));
        _facetExtractor = new GlobFacetExtractor(_timeProvider);
        _sealExtractor = new FacetSealExtractor(_facetExtractor, _timeProvider);
        _testDir = Path.Combine(Path.GetTempPath(), $"facet-integration-{Guid.NewGuid():N}");
        Directory.CreateDirectory(_testDir);
    }

    public void Dispose()
    {
        if (Directory.Exists(_testDir))
        {
            Directory.Delete(_testDir, recursive: true);
        }
    }

    #region Helper Methods

    private MemoryStream CreateTarArchive(Dictionary<string, string> files)
    {
        var stream = new MemoryStream();
        using (var tarWriter = new TarWriter(stream, TarEntryFormat.Pax, leaveOpen: true))
        {
            foreach (var (path, content) in files)
            {
                var entry = new PaxTarEntry(TarEntryType.RegularFile, path.TrimStart('/'))
                {
                    DataStream = new MemoryStream(Encoding.UTF8.GetBytes(content))
                };
                tarWriter.WriteEntry(entry);
            }
        }

        stream.Position = 0;
        return stream;
    }

    private MemoryStream CreateOciLayer(Dictionary<string, string> files)
    {
        var tarStream = CreateTarArchive(files);
        var gzipStream = new MemoryStream();

        using (var gzip = new GZipStream(gzipStream, CompressionMode.Compress, leaveOpen: true))
        {
            tarStream.CopyTo(gzip);
        }

        gzipStream.Position = 0;
        return gzipStream;
    }

    #endregion

    #region Tar Extraction Tests

    [Fact]
    public async Task ExtractFromTarAsync_ValidTar_ExtractsFacets()
    {
        // Arrange
        var files = new Dictionary<string, string>
        {
            { "/var/lib/dpkg/status", "Package: nginx\nVersion: 1.0" },
            { "/etc/nginx/nginx.conf", "server { listen 80; }" },
            { "/usr/bin/nginx", "binary_content" }
        };

        using var tarStream = CreateTarArchive(files);

        // Act
        var result = await _sealExtractor.ExtractFromTarAsync(
            tarStream,
            ct: TestContext.Current.CancellationToken);

        // Assert
        result.Should().NotBeNull();
        result!.Facets.Should().NotBeEmpty();
        result.CombinedMerkleRoot.Should().StartWith("sha256:");
        result.Stats.Should().NotBeNull();
        result.Stats!.TotalFilesProcessed.Should().BeGreaterThanOrEqualTo(3);
    }

    [Fact]
    public async Task ExtractFromTarAsync_EmptyTar_ReturnsEmptyFacets()
    {
        // Arrange
        using var tarStream = CreateTarArchive(new Dictionary<string, string>());

        // Act
        var result = await _sealExtractor.ExtractFromTarAsync(
            tarStream,
            ct: TestContext.Current.CancellationToken);

        // Assert
        result.Should().NotBeNull();
        result!.Facets.Should().BeEmpty();
    }

    [Fact]
    public async Task ExtractFromTarAsync_MatchesDpkgFacet()
    {
        // Arrange
        var files = new Dictionary<string, string>
        {
            { "/var/lib/dpkg/status", "Package: openssl\nVersion: 3.0.0" },
            { "/var/lib/dpkg/info/openssl.list", "/usr/lib/libssl.so" }
        };

        using var tarStream = CreateTarArchive(files);

        // Act
        var result = await _sealExtractor.ExtractFromTarAsync(
            tarStream,
            ct: TestContext.Current.CancellationToken);

        // Assert
        result.Should().NotBeNull();
        var dpkgFacet = result!.Facets.FirstOrDefault(f => f.FacetId == "os-packages-dpkg");
        dpkgFacet.Should().NotBeNull();
        dpkgFacet!.FileCount.Should().BeGreaterThanOrEqualTo(1);
    }

    [Fact]
    public async Task ExtractFromTarAsync_MatchesNodeModulesFacet()
    {
        // Arrange
        var files = new Dictionary<string, string>
        {
            { "/app/node_modules/express/package.json", "{\"name\":\"express\",\"version\":\"4.18.0\"}" },
            { "/app/package-lock.json", "{\"lockfileVersion\":3}" }
        };

        using var tarStream = CreateTarArchive(files);

        // Act
        var result = await _sealExtractor.ExtractFromTarAsync(
            tarStream,
            ct: TestContext.Current.CancellationToken);

        // Assert
        result.Should().NotBeNull();
        var npmFacet = result!.Facets.FirstOrDefault(f => f.FacetId == "lang-deps-npm");
        npmFacet.Should().NotBeNull();
    }

    #endregion

    #region OCI Layer Extraction Tests

    [Fact]
    public async Task ExtractFromOciLayersAsync_SingleLayer_ExtractsFacets()
    {
        // Arrange
        var files = new Dictionary<string, string>
        {
            { "/var/lib/dpkg/status", "Package: curl\nVersion: 7.0" },
            { "/etc/hosts", "127.0.0.1 localhost" }
        };

        using var layerStream = CreateOciLayer(files);
        var layers = new[] { layerStream as Stream };

        // Act
        var result = await _sealExtractor.ExtractFromOciLayersAsync(
            layers,
            ct: TestContext.Current.CancellationToken);

        // Assert
        result.Should().NotBeNull();
        result!.Facets.Should().NotBeEmpty();
        result.CombinedMerkleRoot.Should().StartWith("sha256:");
    }

    [Fact]
    public async Task ExtractFromOciLayersAsync_MultipleLayers_MergesFacets()
    {
        // Arrange - base layer has dpkg, upper layer adds config
        var baseLayerFiles = new Dictionary<string, string>
        {
            { "/var/lib/dpkg/status", "Package: base\nVersion: 1.0" }
        };

        var upperLayerFiles = new Dictionary<string, string>
        {
            { "/etc/nginx/nginx.conf", "server {}" }
        };

        using var baseLayer = CreateOciLayer(baseLayerFiles);
        using var upperLayer = CreateOciLayer(upperLayerFiles);
        var layers = new[] { baseLayer as Stream, upperLayer as Stream };

        // Act
        var result = await _sealExtractor.ExtractFromOciLayersAsync(
            layers,
            ct: TestContext.Current.CancellationToken);

        // Assert
        result.Should().NotBeNull();
        result!.Stats.Should().NotBeNull();
        result.Stats!.TotalFilesProcessed.Should().BeGreaterThanOrEqualTo(2);
    }

    #endregion

    #region Determinism Tests

    [Fact]
    public async Task ExtractFromTarAsync_SameTar_ProducesSameMerkleRoot()
    {
        // Arrange
        var files = new Dictionary<string, string>
        {
            { "/var/lib/dpkg/status", "Package: test\nVersion: 1.0" },
            { "/etc/test.conf", "config content" }
        };

        using var tarStream1 = CreateTarArchive(files);
        using var tarStream2 = CreateTarArchive(files);

        // Act
        var result1 = await _sealExtractor.ExtractFromTarAsync(
            tarStream1,
            ct: TestContext.Current.CancellationToken);

        var result2 = await _sealExtractor.ExtractFromTarAsync(
            tarStream2,
            ct: TestContext.Current.CancellationToken);

        // Assert
        result1.Should().NotBeNull();
        result2.Should().NotBeNull();
        result1!.CombinedMerkleRoot.Should().Be(result2!.CombinedMerkleRoot);
    }

    [Fact]
    public async Task ExtractFromTarAsync_DifferentContent_ProducesDifferentMerkleRoot()
    {
        // Arrange
        var files1 = new Dictionary<string, string>
        {
            { "/var/lib/dpkg/status", "Package: test\nVersion: 1.0" }
        };

        var files2 = new Dictionary<string, string>
        {
            { "/var/lib/dpkg/status", "Package: test\nVersion: 2.0" }
        };

        using var tarStream1 = CreateTarArchive(files1);
        using var tarStream2 = CreateTarArchive(files2);

        // Act
        var result1 = await _sealExtractor.ExtractFromTarAsync(
            tarStream1,
            ct: TestContext.Current.CancellationToken);

        var result2 = await _sealExtractor.ExtractFromTarAsync(
            tarStream2,
            ct: TestContext.Current.CancellationToken);

        // Assert
        result1.Should().NotBeNull();
        result2.Should().NotBeNull();
        result1!.CombinedMerkleRoot.Should().NotBe(result2!.CombinedMerkleRoot);
    }

    #endregion

    #region Options Tests

    [Fact]
    public async Task ExtractFromTarAsync_Disabled_ReturnsNull()
    {
        // Arrange
        var files = new Dictionary<string, string>
        {
            { "/var/lib/dpkg/status", "Package: test" }
        };

        using var tarStream = CreateTarArchive(files);

        // Act
        var result = await _sealExtractor.ExtractFromTarAsync(
            tarStream,
            FacetSealExtractionOptions.Disabled,
            TestContext.Current.CancellationToken);

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

    [Fact]
    public async Task ExtractFromOciLayersAsync_Disabled_ReturnsNull()
    {
        // Arrange
        using var layer = CreateOciLayer(new Dictionary<string, string>
        {
            { "/etc/test.conf", "content" }
        });

        // Act
        var result = await _sealExtractor.ExtractFromOciLayersAsync(
            [layer],
            FacetSealExtractionOptions.Disabled,
            TestContext.Current.CancellationToken);

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

    #endregion

    #region Multi-Facet Category Tests

    [Fact]
    public async Task ExtractFromTarAsync_MultipleCategories_AllCategoriesRepresented()
    {
        // Arrange - files for multiple facet categories
        var files = new Dictionary<string, string>
        {
            // OS Packages
            { "/var/lib/dpkg/status", "Package: nginx" },
            // Language Dependencies
            { "/app/node_modules/express/package.json", "{\"name\":\"express\"}" },
            // Configuration
            { "/etc/nginx/nginx.conf", "server {}" },
            // Certificates
            { "/etc/ssl/certs/ca-cert.pem", "-----BEGIN CERTIFICATE-----" }
        };

        using var tarStream = CreateTarArchive(files);

        // Act
        var result = await _sealExtractor.ExtractFromTarAsync(
            tarStream,
            ct: TestContext.Current.CancellationToken);

        // Assert
        result.Should().NotBeNull();
        result!.Facets.Should().HaveCountGreaterThanOrEqualTo(2);

        var categories = result.Facets.Select(f => f.Category).Distinct().ToList();
        categories.Should().HaveCountGreaterThan(1);
    }

    #endregion
}