using Akka.TestKit.Xunit2;
using Google.Protobuf.WellKnownTypes;
using Grpc.Core;
using Microsoft.Extensions.Logging.Abstractions;
using NSubstitute;
using ZB.MOM.WW.Audit;
using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
using ZB.MOM.WW.ScadaBridge.Commons.Types.Audit;
using ZB.MOM.WW.ScadaBridge.Commons.Types.Enums;
using ZB.MOM.WW.ScadaBridge.Communication.Grpc;

namespace ZB.MOM.WW.ScadaBridge.Communication.Tests;

/// <summary>
/// Flow Debugger (design 2026-09-05 §5.4): <see cref="SiteStreamGrpcServer.PullTraceEvents"/>
/// — request validation, the queue point-read, DTO projection, and the guarantee that it is
/// NOT a reconciliation path (no cursor flip). Also pins that the RPC sits under the
/// PSK-gated <c>/sitestream.SiteStreamService/</c> prefix.
/// </summary>
public class SiteStreamPullTraceEventsTests : TestKit
{
    private readonly ISiteStreamSubscriber _subscriber = Substitute.For<ISiteStreamSubscriber>();

    private SiteStreamGrpcServer CreateServer() => new(_subscriber, NullLogger<SiteStreamGrpcServer>.Instance);

    private static ServerCallContext NewContext()
    {
        var context = Substitute.For<ServerCallContext>();
        context.CancellationToken.Returns(CancellationToken.None);
        return context;
    }

    private static AuditEvent Row(Guid executionId) => ScadaBridgeAuditEventFactory.Create(
        AuditChannel.ScriptTrace, AuditKind.ScriptRun, AuditStatus.Delivered,
        occurredAtUtc: new DateTime(2026, 9, 5, 12, 0, 0, DateTimeKind.Utc), executionId: executionId, sourceSiteId: "site-a");

    [Fact]
    public void PullTraceEvents_IsUnderThePskGatedServicePrefix()
    {
        var method = SiteStreamService.Descriptor.FindMethodByName("PullTraceEvents");
        Assert.NotNull(method);
        Assert.Equal("sitestream.SiteStreamService", SiteStreamService.Descriptor.FullName);
    }

    [Fact]
    public async Task NoQueueWired_ReturnsEmpty()
    {
        var response = await CreateServer().PullTraceEvents(new PullTraceEventsRequest
        {
            ExecutionIds = { Guid.NewGuid().ToString("D") }, MaxEvents = 10,
        }, NewContext());
        Assert.Empty(response.Events);
    }

    [Fact]
    public async Task ReadsByIds_ProjectsDtos_AndNeverFlipsState()
    {
        var queue = Substitute.For<ISiteAuditQueue>();
        var id = Guid.NewGuid();
        var rows = new List<AuditEvent> { Row(id), Row(id) };
        IReadOnlyCollection<Guid>? seenIds = null;
        DateTime seenSince = default;
        int seenLimit = 0;
        queue.ReadByExecutionIdsAsync(
                Arg.Do<IReadOnlyCollection<Guid>>(x => seenIds = x), Arg.Do<DateTime>(x => seenSince = x),
                Arg.Do<int>(x => seenLimit = x), Arg.Any<CancellationToken>())
            .Returns((IReadOnlyList<AuditEvent>)rows);
        var server = CreateServer();
        server.SetSiteAuditQueue(queue);
        var since = new DateTime(2026, 9, 5, 11, 0, 0, DateTimeKind.Utc);

        var response = await server.PullTraceEvents(new PullTraceEventsRequest
        {
            ExecutionIds = { id.ToString("D") }, SinceUtc = Timestamp.FromDateTime(since), MaxEvents = 500,
        }, NewContext());

        Assert.Equal(2, response.Events.Count);
        Assert.Equal(rows[0].EventId.ToString(), response.Events[0].EventId);
        Assert.Equal(new[] { id }, seenIds);
        Assert.Equal(since, seenSince);
        Assert.Equal(500, seenLimit);
        await queue.DidNotReceiveWithAnyArgs().MarkReconciledUpToAsync(default, default, default);
        await queue.DidNotReceiveWithAnyArgs().MarkReconciledAsync(default!, default);
    }

    [Theory]
    [InlineData(0, 1)]
    [InlineData(2001, 1)]
    [InlineData(10, 0)]
    [InlineData(10, 65)]
    public async Task InvalidArguments_AreRejected(int maxEvents, int idCount)
    {
        var server = CreateServer();
        server.SetSiteAuditQueue(Substitute.For<ISiteAuditQueue>());
        var request = new PullTraceEventsRequest { MaxEvents = maxEvents };
        for (var i = 0; i < idCount; i++) request.ExecutionIds.Add(Guid.NewGuid().ToString("D"));

        var ex = await Assert.ThrowsAsync<RpcException>(() => server.PullTraceEvents(request, NewContext()));
        Assert.Equal(StatusCode.InvalidArgument, ex.StatusCode);
    }

    [Fact]
    public async Task NonGuidId_IsRejected()
    {
        var server = CreateServer();
        server.SetSiteAuditQueue(Substitute.For<ISiteAuditQueue>());
        var ex = await Assert.ThrowsAsync<RpcException>(() => server.PullTraceEvents(
            new PullTraceEventsRequest { ExecutionIds = { "nope" }, MaxEvents = 10 }, NewContext()));
        Assert.Equal(StatusCode.InvalidArgument, ex.StatusCode);
    }

    [Fact]
    public async Task QueueFault_CollapsesToEmpty()
    {
        var queue = Substitute.For<ISiteAuditQueue>();
        queue.ReadByExecutionIdsAsync(default!, default, default, default)
            .ReturnsForAnyArgs<IReadOnlyList<AuditEvent>>(_ => throw new InvalidOperationException("boom"));
        var server = CreateServer();
        server.SetSiteAuditQueue(queue);

        var response = await server.PullTraceEvents(
            new PullTraceEventsRequest { ExecutionIds = { Guid.NewGuid().ToString("D") }, MaxEvents = 10 }, NewContext());
        Assert.Empty(response.Events);
    }
}