using System.Text;
using StellaOps.Zastava.Core.Contracts;
using StellaOps.Zastava.Core.Hashing;
using StellaOps.Zastava.Core.Serialization;

namespace StellaOps.Zastava.Core.Tests.Serialization;

public sealed class ZastavaCanonicalJsonSerializerTests
{
    [Fact]
    public void Serialize_RuntimeEventEnvelope_ProducesDeterministicOrdering()
    {
        var runtimeEvent = new RuntimeEvent
        {
            EventId = "evt-123",
            When = DateTimeOffset.Parse("2025-10-19T12:34:56Z"),
            Kind = RuntimeEventKind.ContainerStart,
            Tenant = "tenant-01",
            Node = "node-a",
            Runtime = new RuntimeEngine
            {
                Engine = "containerd",
                Version = "1.7.19"
            },
            Workload = new RuntimeWorkload
            {
                Platform = "kubernetes",
                Namespace = "payments",
                Pod = "api-7c9fbbd8b7-ktd84",
                Container = "api",
                ContainerId = "containerd://abc",
                ImageRef = "ghcr.io/acme/api@sha256:abcd",
                Owner = new RuntimeWorkloadOwner
                {
                    Kind = "Deployment",
                    Name = "api"
                }
            },
            Process = new RuntimeProcess
            {
                Pid = 12345,
                Entrypoint = new[] { "/entrypoint.sh", "--serve" },
                EntryTrace = new[]
                {
                    new RuntimeEntryTrace
                    {
                        File = "/entrypoint.sh",
                        Line = 3,
                        Op = "exec",
                        Target = "/usr/bin/python3"
                    }
                }
            },
            LoadedLibraries = new[]
            {
                new RuntimeLoadedLibrary
                {
                    Path = "/lib/x86_64-linux-gnu/libssl.so.3",
                    Inode = 123456,
                    Sha256 = "abc123"
                }
            },
            Posture = new RuntimePosture
            {
                ImageSigned = true,
                SbomReferrer = "present",
                Attestation = new RuntimeAttestation
                {
                    Uuid = "rekor-uuid",
                    Verified = true
                }
            },
            Delta = new RuntimeDelta
            {
                BaselineImageDigest = "sha256:abcd",
                ChangedFiles = new[] { "/opt/app/server.py" },
                NewBinaries = new[]
                {
                    new RuntimeNewBinary
                    {
                        Path = "/usr/local/bin/helper",
                        Sha256 = "def456"
                    }
                }
            },
            Evidence = new[]
            {
                new RuntimeEvidence
                {
                    Signal = "procfs.maps",
                    Value = "/lib/.../libssl.so.3@0x7f..."
                }
            },
            Annotations = new Dictionary<string, string>
            {
                ["source"] = "unit-test"
            }
        };

        var envelope = RuntimeEventEnvelope.Create(runtimeEvent, ZastavaContractVersions.RuntimeEvent);
        var json = ZastavaCanonicalJsonSerializer.Serialize(envelope);

        var expectedOrder = new[]
        {
            "\"schemaVersion\"",
            "\"event\"",
            "\"eventId\"",
            "\"when\"",
            "\"kind\"",
            "\"tenant\"",
            "\"node\"",
            "\"runtime\"",
            "\"engine\"",
            "\"version\"",
            "\"workload\"",
            "\"platform\"",
            "\"namespace\"",
            "\"pod\"",
            "\"container\"",
            "\"containerId\"",
            "\"imageRef\"",
            "\"owner\"",
            "\"kind\"",
            "\"name\"",
            "\"process\"",
            "\"pid\"",
            "\"entrypoint\"",
            "\"entryTrace\"",
            "\"loadedLibs\"",
            "\"posture\"",
            "\"imageSigned\"",
            "\"sbomReferrer\"",
            "\"attestation\"",
            "\"uuid\"",
            "\"verified\"",
            "\"delta\"",
            "\"baselineImageDigest\"",
            "\"changedFiles\"",
            "\"newBinaries\"",
            "\"path\"",
            "\"sha256\"",
            "\"evidence\"",
            "\"signal\"",
            "\"value\"",
            "\"annotations\"",
            "\"source\""
        };

        var cursor = -1;
        foreach (var token in expectedOrder)
        {
            var position = json.IndexOf(token, cursor + 1, StringComparison.Ordinal);
            Assert.True(position > cursor, $"Property token {token} not found in the expected order.");
            cursor = position;
        }

        Assert.DoesNotContain("  ", json, StringComparison.Ordinal);
        Assert.StartsWith("{\"schemaVersion\"", json, StringComparison.Ordinal);
        Assert.EndsWith("}}", json, StringComparison.Ordinal);
    }

    [Fact]
    public void ComputeMultihash_ProducesStableBase64UrlDigest()
    {
        var decision = AdmissionDecisionEnvelope.Create(
            new AdmissionDecision
            {
                AdmissionId = "admission-123",
                Namespace = "payments",
                PodSpecDigest = "sha256:deadbeef",
                Images = new[]
                {
                    new AdmissionImageVerdict
                    {
                        Name = "ghcr.io/acme/api:1.2.3",
                        Resolved = "ghcr.io/acme/api@sha256:abcd",
                        Signed = true,
                        HasSbomReferrers = true,
                        PolicyVerdict = PolicyVerdict.Pass,
                        Reasons = Array.Empty<string>(),
                        Rekor = new AdmissionRekorEvidence
                        {
                            Uuid = "xyz",
                            Verified = true
                        }
                    }
                },
                Decision = AdmissionDecisionOutcome.Allow,
                TtlSeconds = 300
            },
            ZastavaContractVersions.AdmissionDecision);

        var canonicalJson = ZastavaCanonicalJsonSerializer.Serialize(decision);
        var expectedDigestBytes = SHA256.HashData(Encoding.UTF8.GetBytes(canonicalJson));
        var expected = $"sha256-{Convert.ToBase64String(expectedDigestBytes).TrimEnd('=').Replace('+', '-').Replace('/', '_')}";

        var hash = ZastavaHashing.ComputeMultihash(decision);

        Assert.Equal(expected, hash);

        var sha512 = ZastavaHashing.ComputeMultihash(Encoding.UTF8.GetBytes(canonicalJson), "sha512");
        Assert.StartsWith("sha512-", sha512, StringComparison.Ordinal);
    }
}