// -----------------------------------------------------------------------------
// AuditBundleWriterTests.cs
// Sprint: SPRINT_4300_0001_0002 (One-Command Audit Replay CLI)
// Description: Unit tests for AuditBundleWriter.
// -----------------------------------------------------------------------------

using System.Text;
using System.Text.Json;
using StellaOps.AuditPack.Services;

namespace StellaOps.AuditPack.Tests;

public class AuditBundleWriterTests : IDisposable
{
    private readonly string _tempDir;

    public AuditBundleWriterTests()
    {
        _tempDir = Path.Combine(Path.GetTempPath(), $"audit-test-{Guid.NewGuid():N}");
        Directory.CreateDirectory(_tempDir);
    }

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

    [Fact]
    public async Task WriteAsync_CreatesValidBundle()
    {
        // Arrange
        var writer = new AuditBundleWriter();
        var outputPath = Path.Combine(_tempDir, "test-bundle.tar.gz");

        var request = CreateValidRequest(outputPath);

        // Act
        var result = await writer.WriteAsync(request);

        // Assert
        Assert.True(result.Success, result.Error);
        Assert.True(File.Exists(outputPath));
        Assert.NotNull(result.BundleId);
        Assert.NotNull(result.MerkleRoot);
        Assert.NotNull(result.BundleDigest);
        Assert.True(result.TotalSizeBytes > 0);
        Assert.True(result.FileCount > 0);
    }

    [Fact]
    public async Task WriteAsync_ComputesMerkleRoot()
    {
        // Arrange
        var writer = new AuditBundleWriter();
        var outputPath = Path.Combine(_tempDir, "merkle-test.tar.gz");

        var request = CreateValidRequest(outputPath);

        // Act
        var result = await writer.WriteAsync(request);

        // Assert
        Assert.True(result.Success);
        Assert.NotNull(result.MerkleRoot);
        Assert.StartsWith("sha256:", result.MerkleRoot);
        Assert.Equal(71, result.MerkleRoot.Length); // sha256: + 64 hex chars
    }

    [Fact]
    public async Task WriteAsync_SignsManifest_WhenSignIsTrue()
    {
        // Arrange
        var writer = new AuditBundleWriter();
        var outputPath = Path.Combine(_tempDir, "signed-test.tar.gz");

        var request = CreateValidRequest(outputPath) with { Sign = true };

        // Act
        var result = await writer.WriteAsync(request);

        // Assert
        Assert.True(result.Success);
        Assert.True(result.Signed);
        Assert.NotNull(result.SigningKeyId);
        Assert.NotNull(result.SigningAlgorithm);
    }

    [Fact]
    public async Task WriteAsync_DoesNotSign_WhenSignIsFalse()
    {
        // Arrange
        var writer = new AuditBundleWriter();
        var outputPath = Path.Combine(_tempDir, "unsigned-test.tar.gz");

        var request = CreateValidRequest(outputPath) with { Sign = false };

        // Act
        var result = await writer.WriteAsync(request);

        // Assert
        Assert.True(result.Success);
        Assert.False(result.Signed);
        Assert.Null(result.SigningKeyId);
    }

    [Fact]
    public async Task WriteAsync_FailsWithoutSbom()
    {
        // Arrange
        var writer = new AuditBundleWriter();
        var outputPath = Path.Combine(_tempDir, "no-sbom.tar.gz");

        var request = new AuditBundleWriteRequest
        {
            OutputPath = outputPath,
            ScanId = "scan-001",
            ImageRef = "test:latest",
            ImageDigest = "sha256:abc123",
            Decision = "pass",
            Sbom = null!,
            FeedsSnapshot = CreateFeedsSnapshot(),
            PolicyBundle = CreatePolicyBundle(),
            Verdict = CreateVerdict()
        };

        // Act
        var result = await writer.WriteAsync(request);

        // Assert
        Assert.False(result.Success);
        Assert.Contains("SBOM", result.Error);
    }

    [Fact]
    public async Task WriteAsync_IncludesOptionalVex()
    {
        // Arrange
        var writer = new AuditBundleWriter();
        var outputPath = Path.Combine(_tempDir, "with-vex.tar.gz");

        var vexContent = Encoding.UTF8.GetBytes(JsonSerializer.Serialize(new
        {
            type = "https://openvex.dev/ns/v0.2.0",
            statements = new[]
            {
                new { vulnerability = "CVE-2024-1234", status = "not_affected" }
            }
        }));

        var request = CreateValidRequest(outputPath) with
        {
            VexStatements = vexContent
        };

        // Act
        var result = await writer.WriteAsync(request);

        // Assert
        Assert.True(result.Success);
        Assert.True(result.FileCount >= 5); // sbom, feeds, policy, verdict, vex
    }

    [Fact]
    public async Task WriteAsync_AddsTimeAnchor()
    {
        // Arrange
        var writer = new AuditBundleWriter();
        var outputPath = Path.Combine(_tempDir, "with-anchor.tar.gz");

        var request = CreateValidRequest(outputPath) with
        {
            TimeAnchor = new TimeAnchorInput
            {
                Timestamp = DateTimeOffset.UtcNow,
                Source = "local"
            }
        };

        // Act
        var result = await writer.WriteAsync(request);

        // Assert
        Assert.True(result.Success);
    }

    [Fact]
    public async Task WriteAsync_DeterministicMerkleRoot()
    {
        // Arrange
        var writer = new AuditBundleWriter();

        var sbom = CreateSbom();
        var feeds = CreateFeedsSnapshot();
        var policy = CreatePolicyBundle();
        var verdict = CreateVerdict();

        var request1 = new AuditBundleWriteRequest
        {
            OutputPath = Path.Combine(_tempDir, "det-1.tar.gz"),
            ScanId = "scan-001",
            ImageRef = "test:latest",
            ImageDigest = "sha256:abc123",
            Decision = "pass",
            Sbom = sbom,
            FeedsSnapshot = feeds,
            PolicyBundle = policy,
            Verdict = verdict,
            Sign = false
        };

        var request2 = request1 with
        {
            OutputPath = Path.Combine(_tempDir, "det-2.tar.gz")
        };

        // Act
        var result1 = await writer.WriteAsync(request1);
        var result2 = await writer.WriteAsync(request2);

        // Assert
        Assert.True(result1.Success);
        Assert.True(result2.Success);
        Assert.Equal(result1.MerkleRoot, result2.MerkleRoot);
    }

    private AuditBundleWriteRequest CreateValidRequest(string outputPath)
    {
        return new AuditBundleWriteRequest
        {
            OutputPath = outputPath,
            ScanId = "scan-001",
            ImageRef = "test:latest",
            ImageDigest = "sha256:abc123def456",
            Decision = "pass",
            Sbom = CreateSbom(),
            FeedsSnapshot = CreateFeedsSnapshot(),
            PolicyBundle = CreatePolicyBundle(),
            Verdict = CreateVerdict(),
            Sign = true
        };
    }

    private static byte[] CreateSbom()
    {
        return Encoding.UTF8.GetBytes(JsonSerializer.Serialize(new
        {
            bomFormat = "CycloneDX",
            specVersion = "1.6",
            version = 1,
            components = Array.Empty<object>()
        }));
    }

    private static byte[] CreateFeedsSnapshot()
    {
        return Encoding.UTF8.GetBytes("{\"type\":\"feed-snapshot\"}\n");
    }

    private static byte[] CreatePolicyBundle()
    {
        // Minimal gzip content
        return new byte[] { 0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
    }

    private static byte[] CreateVerdict()
    {
        return Encoding.UTF8.GetBytes(JsonSerializer.Serialize(new
        {
            decision = "pass",
            evaluatedAt = DateTimeOffset.UtcNow
        }));
    }
}