using System.Threading;
using System.Threading.Tasks;
using FluentAssertions;
using Microsoft.Extensions.Logging.Abstractions;
using StellaOps.Graph.Indexer.Ingestion.Sbom;
using Xunit;

namespace StellaOps.Graph.Indexer.Tests;

public sealed class SbomIngestProcessorTests
{
    [Fact]
    public async Task ProcessAsync_writes_batch_and_records_success_metrics()
    {
        var snapshot = CreateSnapshot();
        var transformer = new SbomIngestTransformer();
        var writer = new CaptureWriter();
        var metrics = new CaptureMetrics();
        var snapshotExporter = new CaptureSnapshotExporter();
        var processor = new SbomIngestProcessor(transformer, writer, metrics, snapshotExporter, NullLogger<SbomIngestProcessor>.Instance);

        await processor.ProcessAsync(snapshot, CancellationToken.None);

        writer.LastBatch.Should().NotBeNull();
        metrics.LastRecord.Should().NotBeNull();
        metrics.LastRecord!.Success.Should().BeTrue();
        metrics.LastRecord.NodeCount.Should().Be(writer.LastBatch!.Nodes.Length);
        metrics.LastRecord.EdgeCount.Should().Be(writer.LastBatch!.Edges.Length);
        snapshotExporter.LastSnapshot.Should().BeSameAs(snapshot);
        snapshotExporter.LastBatch.Should().BeSameAs(writer.LastBatch);
    }

    [Fact]
    public async Task ProcessAsync_records_failure_when_writer_throws()
    {
        var snapshot = CreateSnapshot();
        var transformer = new SbomIngestTransformer();
        var writer = new CaptureWriter(shouldThrow: true);
        var metrics = new CaptureMetrics();
        var snapshotExporter = new CaptureSnapshotExporter();
        var processor = new SbomIngestProcessor(transformer, writer, metrics, snapshotExporter, NullLogger<SbomIngestProcessor>.Instance);

        var act = () => processor.ProcessAsync(snapshot, CancellationToken.None);

        await act.Should().ThrowAsync<InvalidOperationException>();
        metrics.LastRecord.Should().NotBeNull();
        metrics.LastRecord!.Success.Should().BeFalse();
        snapshotExporter.LastSnapshot.Should().BeNull();
        snapshotExporter.LastBatch.Should().BeNull();
    }

    private static SbomSnapshot CreateSnapshot()
    {
        return new SbomSnapshot
        {
            Tenant = "tenant-alpha",
            Source = "scanner.sbom.v1",
            ArtifactDigest = "sha256:test-artifact",
            SbomDigest = "sha256:test-sbom",
            CollectedAt = DateTimeOffset.Parse("2025-10-30T12:00:00Z"),
            EventOffset = 1000,
            Artifact = new SbomArtifactMetadata
            {
                DisplayName = "registry.example.com/app:latest",
                Environment = "prod",
                Labels = new[] { "demo" },
                OriginRegistry = "registry.example.com",
                SupplyChainStage = "deploy"
            },
            Build = new SbomBuildMetadata
            {
                BuilderId = "builder://tekton/default",
                BuildType = "https://slsa.dev/provenance/v1",
                AttestationDigest = "sha256:attestation",
                Source = "scanner.build.v1",
                CollectedAt = DateTimeOffset.Parse("2025-10-30T12:00:05Z"),
                EventOffset = 2000
            },
            Components = new[]
            {
                new SbomComponent
                {
                    Purl = "pkg:nuget/Example.Primary@1.0.0",
                    Version = "1.0.0",
                    Ecosystem = "nuget",
                    Scope = "runtime",
                    License = new SbomLicense
                    {
                        Spdx = "MIT",
                        Name = "MIT License",
                        Classification = "permissive",
                        SourceDigest = "sha256:license001"
                    },
                    Usage = "direct",
                    DetectedBy = "sbom.analyzer.transformer",
                    LayerDigest = "sha256:layer",
                    EvidenceDigest = "sha256:evidence",
                    CollectedAt = DateTimeOffset.Parse("2025-10-30T12:00:01Z"),
                    EventOffset = 1201,
                    Source = "scanner.component.v1",
                    Files = new[]
                    {
                        new SbomComponentFile
                        {
                            Path = "/src/app/Program.cs",
                            ContentSha256 = "sha256:file",
                            LanguageHint = "csharp",
                            SizeBytes = 1024,
                            Scope = "build",
                            DetectedBy = "sbom.analyzer.transformer",
                            EvidenceDigest = "sha256:file-evidence",
                            CollectedAt = DateTimeOffset.Parse("2025-10-30T12:00:02Z"),
                            EventOffset = 1202,
                            Source = "scanner.layer.v1"
                        }
                    },
                    Dependencies = Array.Empty<SbomDependency>(),
                    SourceType = "inventory"
                }
            },
            BaseArtifacts = new[]
            {
                new SbomBaseArtifact
                {
                    ArtifactDigest = "sha256:base",
                    SbomDigest = "sha256:base-sbom",
                    DisplayName = "registry.example.com/base:2025.09",
                    Environment = "prod",
                    Labels = new[] { "base-image" },
                    OriginRegistry = "registry.example.com",
                    SupplyChainStage = "build",
                    CollectedAt = DateTimeOffset.Parse("2025-10-22T08:00:00Z"),
                    EventOffset = 800,
                    Source = "scanner.sbom.v1"
                }
            }
        };
    }

    private sealed class CaptureWriter : IGraphDocumentWriter
    {
        private readonly bool _shouldThrow;

        public CaptureWriter(bool shouldThrow = false)
        {
            _shouldThrow = shouldThrow;
        }

        public GraphBuildBatch? LastBatch { get; private set; }

        public Task WriteAsync(GraphBuildBatch batch, CancellationToken cancellationToken)
        {
            LastBatch = batch;

            if (_shouldThrow)
            {
                throw new InvalidOperationException("Simulated persistence failure");
            }

            return Task.CompletedTask;
        }
    }

    private sealed class CaptureMetrics : ISbomIngestMetrics
    {
        public MetricRecord? LastRecord { get; private set; }

        public void RecordBatch(string source, string tenant, int nodeCount, int edgeCount, TimeSpan duration, bool success)
        {
            LastRecord = new MetricRecord(source, tenant, nodeCount, edgeCount, duration, success);
        }
    }

    private sealed class CaptureSnapshotExporter : ISbomSnapshotExporter
    {
        public SbomSnapshot? LastSnapshot { get; private set; }
        public GraphBuildBatch? LastBatch { get; private set; }

        public Task ExportAsync(SbomSnapshot snapshot, GraphBuildBatch batch, CancellationToken cancellationToken)
        {
            LastSnapshot = snapshot;
            LastBatch = batch;
            return Task.CompletedTask;
        }
    }

    private sealed record MetricRecord(
        string Source,
        string Tenant,
        int NodeCount,
        int EdgeCount,
        TimeSpan Duration,
        bool Success);
}