using Microsoft.Extensions.Options;
using ZB.MOM.WW.Secrets.Abstractions;
using ZB.MOM.WW.Secrets.Replicator.Grpc.V1;

namespace ZB.MOM.WW.Secrets.Replicator.Grpc.Tests;

/// <summary>
/// The real hub client, driven over a fake <c>CallInvoker</c>: what it puts on the wire (credential
/// and deadline) and what it does with what comes back (per-item conversion, per-item isolation).
/// </summary>
/// <remarks>
/// Everything here is deliberately exercised through <c>GrpcSecretsHubClient</c> itself rather than
/// through a fake of the <c>ISecretsHubReader</c> seam. A seam fake proves nothing about the header,
/// the deadline, or the conversion — all three live only in this class, and all three are exactly
/// where a follower silently talks to the hub wrong.
/// </remarks>
public sealed class GrpcSecretsHubClientTests
{
    private static readonly DateTimeOffset Now = new(2026, 8, 7, 12, 0, 0, TimeSpan.Zero);

    private readonly FakeSecretsHubCallInvoker _invoker = new();
    private readonly RecordingLogger<GrpcSecretsHubClient> _logger = new();

    private readonly SecretsGrpcHubClientOptions _options = new()
    {
        Endpoint = "https://central:5001",
        BearerToken = "hub-token",
        CallDeadline = TimeSpan.FromSeconds(17),
    };

    private GrpcSecretsHubClient CreateClient() => new(
        new SecretsHub.SecretsHubClient(_invoker),
        Options.Create(_options),
        _logger,
        new FixedTimeProvider(Now));

    [Fact]
    public async Task Every_call_presents_the_bearer_credential()
    {
        _invoker.ManifestResponse = new GetManifestResponse { Entries = { TestWire.Entry("db/password") } };
        _invoker.SecretsResponse = new GetSecretsResponse { Secrets = { TestWire.Row("db/password", 0xAA) } };

        GrpcSecretsHubClient client = CreateClient();

        await client.GetManifestAsync(CancellationToken.None);
        await client.GetManyAsync([new SecretName("db/password")], CancellationToken.None);

        Assert.Equal(["GetManifest", "GetSecrets"], _invoker.Methods);
        Assert.Equal("Bearer hub-token", _invoker.AuthorizationOn(0));
        Assert.Equal("Bearer hub-token", _invoker.AuthorizationOn(1));
    }

    [Fact]
    public async Task Every_call_carries_a_deadline_of_now_plus_the_configured_budget()
    {
        await CreateClient().GetManifestAsync(CancellationToken.None);

        Assert.Equal(Now.UtcDateTime.AddSeconds(17), _invoker.Calls[0].Deadline);
    }

    [Fact]
    public async Task The_deadline_is_recomputed_per_call_rather_than_cached()
    {
        // A CallOptions built once at construction would carry an absolute deadline that expires
        // shortly after startup and then fails every sweep forever, which reads as a hub outage.
        GrpcSecretsHubClient client = CreateClient();

        await client.GetManifestAsync(CancellationToken.None);
        await client.GetManifestAsync(CancellationToken.None);

        Assert.Equal(_invoker.Calls[0].Deadline, _invoker.Calls[1].Deadline);
        Assert.NotSame(_invoker.Calls[0].Headers, _invoker.Calls[1].Headers);
    }

    [Fact]
    public async Task The_fetch_asks_for_exactly_the_names_it_was_given()
    {
        _invoker.SecretsResponse = new GetSecretsResponse();

        await CreateClient().GetManyAsync(
            [new SecretName("db/password"), new SecretName("api/key")], CancellationToken.None);

        Assert.Equal(["db/password", "api/key"], _invoker.LastSecretsRequest!.Names);
    }

    [Fact]
    public async Task A_wire_row_comes_back_as_a_domain_row()
    {
        _invoker.SecretsResponse = new GetSecretsResponse { Secrets = { TestWire.Row("db/password", 0xAA) } };

        IReadOnlyList<StoredSecret> rows =
            await CreateClient().GetManyAsync([new SecretName("db/password")], CancellationToken.None);

        StoredSecret row = Assert.Single(rows);
        Assert.Equal("db/password", row.Name.Value);
        Assert.Equal(SecretContentType.Text, row.ContentType);
        Assert.Equal(new byte[] { 0xAA }, row.Ciphertext);
        Assert.Equal(TestWire.FixedInstant, row.UpdatedUtc);
    }

    [Fact]
    public async Task A_wire_manifest_entry_comes_back_as_a_domain_entry()
    {
        _invoker.ManifestResponse = new GetManifestResponse { Entries = { TestWire.Entry("api/key") } };

        IReadOnlyList<SecretManifestEntry> entries =
            await CreateClient().GetManifestAsync(CancellationToken.None);

        SecretManifestEntry entry = Assert.Single(entries);
        Assert.Equal("api/key", entry.Name.Value);
        Assert.Equal(TestWire.FixedInstant, entry.UpdatedUtc);
    }

    [Fact]
    public async Task A_malformed_row_is_dropped_and_its_well_formed_siblings_survive()
    {
        // The whole point: one unparseable row must not cost the batch. Eagerly materializing the
        // response would fail all three, and the identical pull set would re-fail every interval.
        SecretRow bad = TestWire.Row("api/key", 0xBB);
        bad.ContentType = "Kerberos";

        _invoker.SecretsResponse = new GetSecretsResponse
        {
            Secrets = { TestWire.Row("db/password", 0xAA), bad, TestWire.Row("svc/token", 0xCC) },
        };

        IReadOnlyList<StoredSecret> rows = await CreateClient().GetManyAsync(
            [new SecretName("db/password"), new SecretName("api/key"), new SecretName("svc/token")],
            CancellationToken.None);

        Assert.Equal(["db/password", "svc/token"], rows.Select(r => r.Name.Value));
    }

    [Fact]
    public async Task A_dropped_row_costs_exactly_one_warning_that_names_it()
    {
        SecretRow bad = TestWire.Row("api/key", 0xBB);
        bad.ContentType = "Kerberos";

        _invoker.SecretsResponse = new GetSecretsResponse
        {
            Secrets = { TestWire.Row("db/password", 0xAA), bad },
        };

        await CreateClient().GetManyAsync(
            [new SecretName("db/password"), new SecretName("api/key")], CancellationToken.None);

        string warning = Assert.Single(_logger.Warnings);
        Assert.Contains("api/key", warning, StringComparison.Ordinal);
    }

    [Fact]
    public async Task A_dropped_row_never_logs_the_material_it_was_carrying()
    {
        // A parse failure is an operations problem, so it is logged — but a replicated row is
        // ciphertext plus its wrapped DEK, and none of that may reach a log sink.
        SecretRow bad = TestWire.Row("api/key", 0xBB);
        bad.UpdatedUtc = "yesterday";

        _invoker.SecretsResponse = new GetSecretsResponse { Secrets = { bad } };

        await CreateClient().GetManyAsync([new SecretName("api/key")], CancellationToken.None);

        string warning = Assert.Single(_logger.Warnings);

        foreach (string forbidden in new[] { "sha256:test", "hub-token", "Ciphertext", "WrappedDek" })
        {
            Assert.DoesNotContain(forbidden, warning, StringComparison.OrdinalIgnoreCase);
        }
    }

    [Fact]
    public async Task A_row_whose_own_name_is_unparseable_is_dropped_without_echoing_it()
    {
        // The name is the one field a warning may legitimately carry — but here the name IS what
        // failed to parse, so it is replaced by a marker rather than trusted into the log line.
        SecretRow bad = TestWire.Row("db/password", 0xAA);
        bad.Name = "../../etc/passwd";

        _invoker.SecretsResponse = new GetSecretsResponse { Secrets = { bad } };

        IReadOnlyList<StoredSecret> rows =
            await CreateClient().GetManyAsync([new SecretName("db/password")], CancellationToken.None);

        Assert.Empty(rows);

        string warning = Assert.Single(_logger.Warnings);
        Assert.DoesNotContain("etc/passwd", warning, StringComparison.Ordinal);
    }

    [Fact]
    public async Task A_malformed_manifest_entry_is_dropped_and_the_rest_of_the_manifest_survives()
    {
        ManifestEntry bad = TestWire.Entry("api/key");
        bad.UpdatedUtc = "not-a-timestamp";

        _invoker.ManifestResponse = new GetManifestResponse
        {
            Entries = { TestWire.Entry("db/password"), bad, TestWire.Entry("svc/token") },
        };

        IReadOnlyList<SecretManifestEntry> entries =
            await CreateClient().GetManifestAsync(CancellationToken.None);

        Assert.Equal(["db/password", "svc/token"], entries.Select(e => e.Name.Value));
        Assert.Single(_logger.Warnings);
    }

    [Fact]
    public async Task Conversion_preserves_the_order_the_hub_sent()
    {
        _invoker.SecretsResponse = new GetSecretsResponse
        {
            Secrets = { TestWire.Row("db/password", 0xAA), TestWire.Row("api/key", 0xBB) },
        };

        IReadOnlyList<StoredSecret> rows = await CreateClient().GetManyAsync(
            [new SecretName("db/password"), new SecretName("api/key")], CancellationToken.None);

        Assert.Equal(["db/password", "api/key"], rows.Select(r => r.Name.Value));
    }

    [Fact]
    public async Task A_well_formed_response_logs_nothing()
    {
        _invoker.ManifestResponse = new GetManifestResponse { Entries = { TestWire.Entry("db/password") } };

        await CreateClient().GetManifestAsync(CancellationToken.None);

        Assert.Empty(_logger.Warnings);
        Assert.Empty(_logger.Information);
    }
}