using System.Collections.Immutable;
using FluentAssertions;
using Microsoft.Extensions.Logging.Abstractions;
using StellaOps.Evidence.Models;
using StellaOps.Replay.Engine;
using StellaOps.Replay.Models;
using StellaOps.Testing.Manifests.Models;
using Xunit;

using StellaOps.TestKit;
namespace StellaOps.Replay.Tests;

public class ReplayEngineTests
{
    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public async Task Replay_SameManifest_ProducesIdenticalVerdict()
    {
        var manifest = CreateManifest();
        var engine = CreateEngine();

        var result1 = await engine.ReplayAsync(manifest, new ReplayOptions());
        var result2 = await engine.ReplayAsync(manifest, new ReplayOptions());

        result1.VerdictDigest.Should().Be(result2.VerdictDigest);
    }

    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public async Task Replay_DifferentManifest_ProducesDifferentVerdict()
    {
        var manifest1 = CreateManifest();
        var manifest2 = manifest1 with
        {
            PolicySnapshot = manifest1.PolicySnapshot with { LatticeRulesDigest = new string('f', 64) }
        };

        var engine = CreateEngine();
        var result1 = await engine.ReplayAsync(manifest1, new ReplayOptions());
        var result2 = await engine.ReplayAsync(manifest2, new ReplayOptions());

        result1.VerdictDigest.Should().NotBe(result2.VerdictDigest);
    }

    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public void CheckDeterminism_IdenticalResults_ReturnsTrue()
    {
        var engine = CreateEngine();
        var result1 = new ReplayResult { RunId = "1", VerdictDigest = "abc123", Success = true, ExecutedAt = DateTimeOffset.UtcNow };
        var result2 = new ReplayResult { RunId = "1", VerdictDigest = "abc123", Success = true, ExecutedAt = DateTimeOffset.UtcNow };

        var check = engine.CheckDeterminism(result1, result2);

        check.IsDeterministic.Should().BeTrue();
    }

    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public void CheckDeterminism_DifferentResults_ReturnsDifferences()
    {
        var engine = CreateEngine();
        var result1 = new ReplayResult
        {
            RunId = "1",
            VerdictJson = "{\"score\":100}",
            VerdictDigest = "abc123",
            Success = true,
            ExecutedAt = DateTimeOffset.UtcNow
        };
        var result2 = new ReplayResult
        {
            RunId = "1",
            VerdictJson = "{\"score\":99}",
            VerdictDigest = "def456",
            Success = true,
            ExecutedAt = DateTimeOffset.UtcNow
        };

        var check = engine.CheckDeterminism(result1, result2);

        check.IsDeterministic.Should().BeFalse();
        check.Differences.Should().NotBeEmpty();
    }

    private static ReplayEngine CreateEngine()
    {
        return new ReplayEngine(
            new FakeFeedLoader(),
            new FakePolicyLoader(),
            new FakeScannerFactory(),
            NullLogger<ReplayEngine>.Instance);
    }

    private static RunManifest CreateManifest()
    {
        return new RunManifest
        {
            RunId = Guid.NewGuid().ToString(),
            SchemaVersion = "1.0.0",
            ArtifactDigests = ImmutableArray.Create(new ArtifactDigest("sha256", new string('a', 64), null, null)),
            FeedSnapshot = new FeedSnapshot("nvd", "v1", new string('b', 64), DateTimeOffset.UtcNow.AddHours(-1)),
            PolicySnapshot = new PolicySnapshot("1.0.0", new string('c', 64), ImmutableArray<string>.Empty),
            ToolVersions = new ToolVersions("1.0.0", "1.0.0", "1.0.0", "1.0.0", ImmutableDictionary<string, string>.Empty),
            CryptoProfile = new CryptoProfile("default", ImmutableArray<string>.Empty, ImmutableArray<string>.Empty),
            EnvironmentProfile = new EnvironmentProfile("postgres-only", false, null, null),
            CanonicalizationVersion = "1.0.0",
            InitiatedAt = DateTimeOffset.UtcNow
        };
    }

    private sealed class FakeFeedLoader : IFeedLoader
    {
        public Task<FeedSnapshot> LoadByDigestAsync(string digest, CancellationToken ct = default)
            => Task.FromResult(new FeedSnapshot("nvd", "v1", digest, DateTimeOffset.UtcNow.AddHours(-1)));
    }

    private sealed class FakePolicyLoader : IPolicyLoader
    {
        public Task<PolicySnapshot> LoadByDigestAsync(string digest, CancellationToken ct = default)
            => Task.FromResult(new PolicySnapshot("1.0.0", digest, ImmutableArray<string>.Empty));
    }

    private sealed class FakeScannerFactory : IScannerFactory
    {
        public IScanner Create(ScannerOptions options) => new FakeScanner(options);
    }

    private sealed class FakeScanner : IScanner
    {
        private readonly ScannerOptions _options;
        public FakeScanner(ScannerOptions options) => _options = options;

        public Task<ScanResult> ScanAsync(ImmutableArray<ArtifactDigest> artifacts, CancellationToken ct = default)
        {
            var verdict = new
            {
                feedVersion = _options.FeedSnapshot.Version,
                policyDigest = _options.PolicySnapshot.LatticeRulesDigest
            };
            var evidence = new EvidenceIndex
            {
                IndexId = Guid.NewGuid().ToString(),
                SchemaVersion = "1.0.0",
                Verdict = new VerdictReference("v1", new string('d', 64), VerdictOutcome.Pass, null),
                Sboms = ImmutableArray<SbomEvidence>.Empty,
                Attestations = ImmutableArray<AttestationEvidence>.Empty,
                ToolChain = new ToolChainEvidence("1", "1", "1", "1", "1", ImmutableDictionary<string, string>.Empty),
                RunManifestDigest = new string('e', 64),
                CreatedAt = DateTimeOffset.UtcNow
            };
            return Task.FromResult(new ScanResult(verdict, evidence, 10));
        }
    }
}