using System.Text.Json;
using Akka.Actor;
using Akka.TestKit.Xunit2;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging.Abstractions;
using NSubstitute;
using ZB.MOM.WW.ScadaBridge.Commons.Entities.InboundApi;
using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Repositories;
using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
using ZB.MOM.WW.ScadaBridge.Commons.Messages.Communication;
using ZB.MOM.WW.ScadaBridge.Commons.Messages.Management;
using ZB.MOM.WW.ScadaBridge.InboundAPI;

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

/// <summary>
/// ScadaBridge#75: an inbound method whose script fails to compile answers callers with a
/// generic message and its real diagnostic used to reach only the central log. The
/// management surface now returns the diagnostics (<c>ValidateApiMethod</c>), shows the
/// node's compile state on <c>GetApiMethod</c>, and can clear a stale failure without a
/// full-replace update (<c>RecompileApiMethod</c>).
/// </summary>
public class ApiMethodCompileDiagnosticsTests : TestKit
{
    private const string BrokenScript = "return doesNotExist;";
    private readonly ServiceCollection _services = new ServiceCollection().AddTestConfigurationTransaction();
    private readonly IInboundApiRepository _apiRepo = Substitute.For<IInboundApiRepository>();
    private readonly IAuditService _audit = Substitute.For<IAuditService>();
    private readonly InboundScriptExecutor _executor =
        new(NullLogger<InboundScriptExecutor>.Instance, Substitute.For<IServiceProvider>());
    private readonly ApiMethod _method = new("Broken", BrokenScript) { Id = 5, TimeoutSeconds = 10 };
    // The other central node, reached only through the peer invalidation (ScadaBridge#103).
    private readonly InboundScriptExecutor _peerExecutor =
        new(NullLogger<InboundScriptExecutor>.Instance, Substitute.For<IServiceProvider>());
    private readonly ApiMethodCache _peerMethodCache = new(TimeSpan.FromHours(1));
    private readonly PeerCacheInvalidationPublisher _publisher;

    /// <summary>Initializes the harness with a real executor and a stubbed repository.</summary>
    public ApiMethodCompileDiagnosticsTests()
    {
        _services.AddScoped(_ => _apiRepo);
        _services.AddScoped(_ => _audit);
        _services.AddSingleton(_executor);
        _publisher = new PeerCacheInvalidationPublisher(
            new InboundApiCacheInvalidationHandler(_peerExecutor, _peerMethodCache));
        _services.AddSingleton<ICentralCacheInvalidationPublisher>(_publisher);
        _apiRepo.GetApiMethodByIdAsync(5, Arg.Any<CancellationToken>()).Returns(_method);
        _apiRepo.SaveChangesAsync(Arg.Any<CancellationToken>()).Returns(1);
    }

    private JsonElement Send(object command, string role = "Designer")
    {
        var actor = Sys.ActorOf(Props.Create(() => new ManagementActor(
            _services.BuildServiceProvider(), NullLogger<ManagementActor>.Instance)));
        actor.Tell(new ManagementEnvelope(
            new AuthenticatedUser("designer", "Designer", new[] { role }, Array.Empty<string>()),
            command, Guid.NewGuid().ToString("N")));
        var response = ExpectMsg<ManagementSuccess>(TimeSpan.FromSeconds(30));
        return JsonDocument.Parse(response.JsonData).RootElement.Clone();
    }

    /// <summary>
    /// After the data plane recorded a compile failure, GetApiMethod reports it with the real
    /// compiler diagnostic, alongside the unchanged entity fields.
    /// </summary>
    [Fact]
    public void Get_AfterACompileFailure_ReportsKnownBadWithTheDiagnostic()
    {
        Assert.False(_executor.CompileAndRegister(_method));

        var result = Send(new GetApiMethodCommand(5), role: "Viewer");

        Assert.Equal("Broken", result.GetProperty("name").GetString());
        Assert.Equal(BrokenScript, result.GetProperty("script").GetString());
        Assert.True(result.GetProperty("isKnownBad").GetBoolean());
        Assert.False(result.GetProperty("isCompiled").GetBoolean());
        Assert.Contains("doesNotExist", result.GetProperty("lastCompileError").GetString());
    }

    /// <summary>Validate returns the diagnostics and leaves the handler cache untouched.</summary>
    [Fact]
    public void Validate_ReturnsDiagnostics_WithoutRecordingAFailure()
    {
        var result = Send(new ValidateApiMethodCommand(5));

        Assert.False(result.GetProperty("success").GetBoolean());
        Assert.Contains(result.GetProperty("errors").EnumerateArray(),
            e => e.GetString()!.Contains("doesNotExist", StringComparison.Ordinal));
        var state = _executor.GetCompileState("Broken", BrokenScript);
        Assert.False(state.IsKnownBad);
        Assert.False(state.IsCompiled);
    }

    /// <summary>
    /// A failure recorded for unchanged script text is cleared by a recompile once the cause
    /// outside the script is gone — here modelled by the stored row now compiling — without
    /// re-sending the entity. The recompile is audited.
    /// </summary>
    [Fact]
    public void Recompile_ClearsAStaleFailure_AndIsAudited()
    {
        Assert.False(_executor.CompileAndRegister(_method));
        _method.Script = "return 1;";

        var result = Send(new RecompileApiMethodCommand(5));

        Assert.True(result.GetProperty("success").GetBoolean());
        Assert.Empty(result.GetProperty("errors").EnumerateArray());
        var state = _executor.GetCompileState("Broken", "return 1;");
        Assert.True(state.IsCompiled);
        Assert.False(state.IsKnownBad);
        _audit.Received(1).LogAsync("designer", "Recompile", "ApiMethod", "5", "Broken",
            Arg.Any<object?>(), Arg.Any<CancellationToken>());
    }

    /// <summary>A recompile of a still-broken script records the new diagnostics.</summary>
    [Fact]
    public void Recompile_StillBroken_RecordsTheDiagnostics()
    {
        var result = Send(new RecompileApiMethodCommand(5));

        Assert.False(result.GetProperty("success").GetBoolean());
        var state = _executor.GetCompileState("Broken", BrokenScript);
        Assert.True(state.IsKnownBad);
        Assert.Contains("doesNotExist", state.LastCompileError);
    }

    /// <summary>
    /// ScadaBridge#103: compile state is per node, so a recompile used to clear the known-bad
    /// record only on the node that answered — the peer kept refusing the unchanged script with
    /// SCRIPT_COMPILE_FAILED until it restarted. The recompile now drops the peer's record (and
    /// its cached row), so the peer compiles the current text on its next request.
    /// </summary>
    /// <returns>A task that represents the asynchronous operation.</returns>
    [Fact]
    public async Task Recompile_ClearsTheKnownBadRecordOnThePeerNode()
    {
        Assert.False(_peerExecutor.CompileAndRegister(_method));
        Assert.True(_peerExecutor.GetCompileState("Broken", BrokenScript).IsKnownBad); // positive control
        await _peerMethodCache.GetOrFetchAsync("Broken", _ => Task.FromResult<ApiMethod?>(_method), CancellationToken.None);

        Send(new RecompileApiMethodCommand(5));

        Assert.False(_peerExecutor.GetCompileState("Broken", BrokenScript).IsKnownBad);
        var refetched = false;
        await _peerMethodCache.GetOrFetchAsync("Broken", _ => { refetched = true; return Task.FromResult<ApiMethod?>(_method); }, CancellationToken.None);
        Assert.True(refetched);
        Assert.Equal(new[] { new InboundApiMethodInvalidated("Broken") }, _publisher.Published);
    }

    /// <summary>Negative control: validate changes nothing anywhere, so it tells the peer nothing.</summary>
    [Fact]
    public void Validate_DoesNotTouchThePeer()
    {
        Assert.False(_peerExecutor.CompileAndRegister(_method));

        Send(new ValidateApiMethodCommand(5));

        Assert.True(_peerExecutor.GetCompileState("Broken", BrokenScript).IsKnownBad);
        Assert.Empty(_publisher.Published);
    }

    /// <summary>Validate and recompile are Designer operations, like UpdateApiMethod.</summary>
    /// <param name="command">The command name to send.</param>
    [Theory]
    [InlineData("Validate")]
    [InlineData("Recompile")]
    public void ValidateAndRecompile_RequireDesigner(string command)
    {
        var actor = Sys.ActorOf(Props.Create(() => new ManagementActor(
            _services.BuildServiceProvider(), NullLogger<ManagementActor>.Instance)));
        object message = command == "Validate" ? new ValidateApiMethodCommand(5) : new RecompileApiMethodCommand(5);
        actor.Tell(new ManagementEnvelope(
            new AuthenticatedUser("viewer", "Viewer", new[] { "Viewer" }, Array.Empty<string>()),
            message, Guid.NewGuid().ToString("N")));

        ExpectMsg<ManagementUnauthorized>(TimeSpan.FromSeconds(10));
    }
}