// =============================================================================
// DsseAttestationParserTests.cs
// Golden-file tests for DSSE attestation parsing
// Part of Task T24: Golden-file tests for determinism
// =============================================================================

using FluentAssertions;
using StellaOps.AirGap.Importer.Reconciliation.Parsers;

namespace StellaOps.AirGap.Importer.Tests.Reconciliation;

public sealed class DsseAttestationParserTests
{
    private static readonly string FixturesPath = Path.Combine(
        AppDomain.CurrentDomain.BaseDirectory,
        "Reconciliation", "Fixtures");

    [Fact]
    public async Task ParseAsync_ValidDsse_ExtractsEnvelope()
    {
        // Arrange
        var parser = new DsseAttestationParser();
        var filePath = Path.Combine(FixturesPath, "sample.intoto.json");

        if (!File.Exists(filePath))
        {
            return;
        }

        // Act
        var result = await parser.ParseAsync(filePath);

        // Assert
        result.IsSuccess.Should().BeTrue();
        result.Envelope.Should().NotBeNull();
        result.Envelope!.PayloadType.Should().Be("application/vnd.in-toto+json");
        result.Envelope.Signatures.Should().HaveCount(1);
        result.Envelope.Signatures[0].KeyId.Should().Be("test-key-id");
    }

    [Fact]
    public async Task ParseAsync_ValidDsse_ExtractsStatement()
    {
        // Arrange
        var parser = new DsseAttestationParser();
        var filePath = Path.Combine(FixturesPath, "sample.intoto.json");

        if (!File.Exists(filePath))
        {
            return;
        }

        // Act
        var result = await parser.ParseAsync(filePath);

        // Assert
        result.Statement.Should().NotBeNull();
        result.Statement!.Type.Should().Be("https://in-toto.io/Statement/v1");
        result.Statement.PredicateType.Should().Be("https://slsa.dev/provenance/v1");
        result.Statement.Subjects.Should().HaveCount(1);
    }

    [Fact]
    public async Task ParseAsync_ExtractsSubjectDigests()
    {
        // Arrange
        var parser = new DsseAttestationParser();
        var filePath = Path.Combine(FixturesPath, "sample.intoto.json");

        if (!File.Exists(filePath))
        {
            return;
        }

        // Act
        var result = await parser.ParseAsync(filePath);

        // Assert
        var subject = result.Statement!.Subjects[0];
        subject.Name.Should().Be("test-app");
        subject.GetSha256Digest().Should().Be("sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855");
    }

    [Fact]
    public void IsAttestation_DsseFile_ReturnsTrue()
    {
        var parser = new DsseAttestationParser();
        parser.IsAttestation("test.intoto.json").Should().BeTrue();
        parser.IsAttestation("test.intoto.jsonl").Should().BeTrue();
        parser.IsAttestation("test.dsig").Should().BeTrue();
        parser.IsAttestation("test.dsse").Should().BeTrue();
    }

    [Fact]
    public void IsAttestation_NonDsseFile_ReturnsFalse()
    {
        var parser = new DsseAttestationParser();
        parser.IsAttestation("test.json").Should().BeFalse();
        parser.IsAttestation("test.cdx.json").Should().BeFalse();
        parser.IsAttestation("test.spdx.json").Should().BeFalse();
    }

    [Fact]
    public async Task ParseAsync_Deterministic_SameOutputForSameInput()
    {
        // Arrange
        var parser = new DsseAttestationParser();
        var filePath = Path.Combine(FixturesPath, "sample.intoto.json");

        if (!File.Exists(filePath))
        {
            return;
        }

        // Act - parse twice
        var result1 = await parser.ParseAsync(filePath);
        var result2 = await parser.ParseAsync(filePath);

        // Assert - results should be identical
        result1.Statement!.PredicateType.Should().Be(result2.Statement!.PredicateType);
        result1.Statement.Subjects.Count.Should().Be(result2.Statement.Subjects.Count);
        result1.Statement.Subjects[0].GetSha256Digest()
            .Should().Be(result2.Statement.Subjects[0].GetSha256Digest());
    }

    [Fact]
    public async Task ParseAsync_InvalidJson_ReturnsFailure()
    {
        // Arrange
        var parser = new DsseAttestationParser();
        var json = "not valid json";
        using var stream = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(json));

        // Act
        var result = await parser.ParseAsync(stream);

        // Assert
        result.IsSuccess.Should().BeFalse();
        result.ErrorMessage.Should().Contain("parsing error");
    }
}