using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Commons.Protos;
using ZB.MOM.WW.OtOpcUa.Commons.Protos.MeshTransport.V1;

namespace ZB.MOM.WW.OtOpcUa.Commons.Tests;

/// <summary>
///     Contract-lock for the mesh command envelope's oneof. If a fifth command is added
///     to <c>mesh_transport.proto</c> without adding a matching entry to
///     <see cref="MeshTransportProtoContract.HandledCases"/>, this test goes red — the single guard
///     that keeps the wire contract and the handled-case set from silently drifting apart. A drift
///     here is exactly the failure the whole transport exists to avoid: a command that crosses the
///     mesh boundary, decodes to a case nobody handles, and is dropped without a trace.
/// </summary>
public class MeshTransportProtoContractTests
{
    [Fact]
    public void EveryOneofVariant_IsAccountedFor()
    {
        var variants = System.Enum.GetValues<CommandEnvelope.CommandOneofCase>()
            .Where(c => c != CommandEnvelope.CommandOneofCase.None).ToArray();

        variants.ShouldBe(MeshTransportProtoContract.HandledCases, ignoreOrder: true);
    }

    [Fact]
    public void The_service_base_and_client_types_generate()
    {
        // Referencing these types is the whole assertion — GrpcServices="Both" must emit both halves
        // of both services: central hosts CentralCommandService and dials NodeCommandService, and a
        // driver node does the mirror image, so neither service can ship client-only or server-only.
        typeof(NodeCommandService.NodeCommandServiceBase).ShouldNotBeNull();
        typeof(NodeCommandService.NodeCommandServiceClient).ShouldNotBeNull();
        typeof(CentralCommandService.CentralCommandServiceBase).ShouldNotBeNull();
        typeof(CentralCommandService.CentralCommandServiceClient).ShouldNotBeNull();
    }

    [Fact]
    public void The_apply_outcome_enum_reserves_zero_as_unspecified()
    {
        // proto3 decodes an absent enum field as 0. If 0 meant "Applied", a message that lost the
        // field in transit — or was written by a peer that predates it — would report a deployment
        // as successfully applied when nothing was said at all. 0 must stay meaningless.
        ((int)ApplyOutcome.Unspecified).ShouldBe(0);
        ((int)ApplyOutcome.Applied).ShouldNotBe(0);
        ((int)ApplyOutcome.Failed).ShouldNotBe(0);
    }
}