using System.Text;
using System.Text.Json;
using Api.SeaHavenIndustries.Infrastructure;
using Data.SeaHavenIndustries.Enums;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using SeaHaven.DataServices.Interfaces;
using SeaHaven.Services.Configuration;
using SeaHaven.Services.Implementation;
using SeaHaven.Services.Interfaces;

namespace SeaHavenIndustries.Tests;

public sealed class ShocWebhookVectorTests
{
    private const string FixturePath = "Fixtures/shoc-webhook-test-vectors.json";

    [Fact]
    public async Task All_four_shared_signing_vectors_pass_signature_verification()
    {
        var vectors = await LoadVectorsAsync();
        Assert.True(vectors.Count >= 4, "fixture must ship at least the four shared vectors");

        foreach (var vector in vectors)
        {
            var body = Encoding.UTF8.GetBytes(vector.Body);
            var timestamp = vector.Timestamp.ToString(System.Globalization.CultureInfo.InvariantCulture);
            var signature = "v1=" + vector.ExpectedSignature;
            var at = DateTimeOffset.FromUnixTimeSeconds(vector.Timestamp);

            var data = new RecordingDataService();
            var service = new WorkOrderWebhookService(
                new VectorSecretProvider(vector.Kid, vector.SecretHex),
                data,
                new StaticOptionsMonitor<WorkOrderWebhookOptions>(new WorkOrderWebhookOptions
                {
                    Enabled = true,
                    AllowedClockSkewSeconds = 300,
                    SecretId = "workorder-ingest/shoc-webhook-hmac"
                }),
                new FixedTimeProvider(at),
                NullLogger<WorkOrderWebhookService>.Instance);

            var result = await service.ProcessAsync(
                new WorkOrderWebhookRequest(timestamp, vector.Kid, signature, body),
                CancellationToken.None);

            Assert.True(
                result.Status != WorkOrderWebhookStatus.Unauthorized,
                $"vector {vector.Kid}@{vector.Timestamp} failed signature verification");
        }
    }

    [Fact]
    public async Task Valid_envelope_vectors_are_applied_and_invalid_body_vectors_are_invalid_envelope()
    {
        var vectors = await LoadVectorsAsync();
        var byIndex = vectors.Take(4).ToList();

        var applied = await RunVectorAsync(byIndex[0]);
        Assert.Equal(WorkOrderWebhookStatus.Applied, applied.Status);

        var comment = await RunVectorAsync(byIndex[1]);
        Assert.Equal(WorkOrderWebhookStatus.Applied, comment.Status);

        var empty = await RunVectorAsync(byIndex[2]);
        Assert.Equal(WorkOrderWebhookStatus.InvalidEnvelope, empty.Status);

        var noSource = await RunVectorAsync(byIndex[3]);
        Assert.Equal(WorkOrderWebhookStatus.InvalidEnvelope, noSource.Status);
    }

    private static async Task<WorkOrderWebhookResult> RunVectorAsync(Vector vector)
    {
        var body = Encoding.UTF8.GetBytes(vector.Body);
        var timestamp = vector.Timestamp.ToString(System.Globalization.CultureInfo.InvariantCulture);
        var signature = "v1=" + vector.ExpectedSignature;
        var at = DateTimeOffset.FromUnixTimeSeconds(vector.Timestamp);

        var data = new RecordingDataService();
        var service = new WorkOrderWebhookService(
            new VectorSecretProvider(vector.Kid, vector.SecretHex),
            data,
            new StaticOptionsMonitor<WorkOrderWebhookOptions>(new WorkOrderWebhookOptions
            {
                Enabled = true,
                AllowedClockSkewSeconds = 300,
                SecretId = "workorder-ingest/shoc-webhook-hmac"
            }),
            new FixedTimeProvider(at),
            NullLogger<WorkOrderWebhookService>.Instance);

        return await service.ProcessAsync(
            new WorkOrderWebhookRequest(timestamp, vector.Kid, signature, body),
            CancellationToken.None);
    }

    private static async Task<List<Vector>> LoadVectorsAsync()
    {
        await using var stream = File.OpenRead(FixturePath);
        var document = await JsonDocument.ParseAsync(stream);
        var result = new List<Vector>();
        foreach (var item in document.RootElement.GetProperty("vectors").EnumerateArray())
        {
            result.Add(new Vector(
                item.GetProperty("kid").GetString()!,
                item.GetProperty("secret_hex").GetString()!,
                item.GetProperty("timestamp").GetInt64(),
                item.GetProperty("body").GetString()!,
                item.GetProperty("expected_signature").GetString()!));
        }
        return result;
    }

    private sealed record Vector(
        string Kid,
        string SecretHex,
        long Timestamp,
        string Body,
        string ExpectedSignature);

    private sealed class VectorSecretProvider : IWorkOrderWebhookSecretProvider
    {
        private readonly string _kid;
        private readonly byte[] _secret;

        public VectorSecretProvider(string kid, string secretHex)
        {
            _kid = kid;
            _secret = Encoding.UTF8.GetBytes(secretHex);
        }

        public Task<WorkOrderWebhookSecretResult> GetSecretAsync(
            string keyId,
            CancellationToken cancellationToken) =>
            Task.FromResult(string.Equals(keyId, _kid, StringComparison.Ordinal)
                ? new WorkOrderWebhookSecretResult(
                    WorkOrderWebhookSecretStatus.Found,
                    (byte[])_secret.Clone())
                : new WorkOrderWebhookSecretResult(WorkOrderWebhookSecretStatus.UnknownKey));
    }

    private sealed class RecordingDataService : IWorkOrderWebhookDataService
    {
        public Task<WorkOrderWebhookPersistenceResult> ApplyAsync(
            WorkOrderWebhookMutation mutation,
            CancellationToken cancellationToken) =>
            Task.FromResult(new WorkOrderWebhookPersistenceResult(
                WorkOrderWebhookPersistenceStatus.Applied));
    }
}