using Microsoft.Extensions.Options;

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

/// <summary>
/// Regression: <see cref="CommunicationOptions"/> timeouts feed per-pattern Ask
/// deadlines and gRPC keepalive/stream-lifetime settings; a zero/negative value
/// (or a non-positive <c>GrpcMaxConcurrentStreams</c>) must be rejected at startup
/// by an <see cref="IValidateOptions{TOptions}"/> with a clear, key-naming message
/// rather than surfacing at first Ask/gRPC use.
/// </summary>
public class CommunicationOptionsValidatorTests
{
    private static ValidateOptionsResult Validate(CommunicationOptions options) =>
        new CommunicationOptionsValidator().Validate(Options.DefaultName, options);

    [Fact]
    public void DefaultOptions_AreValid()
    {
        var result = Validate(new CommunicationOptions());
        Assert.True(result.Succeeded, result.FailureMessage);
    }

    [Fact]
    public void ZeroDeploymentTimeout_IsRejected()
    {
        var result = Validate(new CommunicationOptions { DeploymentTimeout = TimeSpan.Zero });
        Assert.True(result.Failed);
        Assert.Contains("DeploymentTimeout", result.FailureMessage);
    }

    [Fact]
    public void NonPositiveGrpcMaxConcurrentStreams_IsRejected()
    {
        var result = Validate(new CommunicationOptions { GrpcMaxConcurrentStreams = 0 });
        Assert.True(result.Failed);
        Assert.Contains("GrpcMaxConcurrentStreams", result.FailureMessage);
    }

    // ── Aggregated live alarm cache options (plan #10, Task 6) ───────────────────

    [Fact]
    public void ZeroLiveAlarmCacheLinger_IsValid()
    {
        // Zero linger = stop the aggregator immediately when the last viewer leaves.
        var result = Validate(new CommunicationOptions { LiveAlarmCacheLinger = TimeSpan.Zero });
        Assert.True(result.Succeeded, result.FailureMessage);
    }

    [Fact]
    public void NegativeLiveAlarmCacheLinger_IsRejected()
    {
        var result = Validate(new CommunicationOptions { LiveAlarmCacheLinger = TimeSpan.FromSeconds(-1) });
        Assert.True(result.Failed);
        Assert.Contains("LiveAlarmCacheLinger", result.FailureMessage);
    }

    [Fact]
    public void ZeroLiveAlarmCacheReconcileInterval_IsRejected()
    {
        var result = Validate(new CommunicationOptions { LiveAlarmCacheReconcileInterval = TimeSpan.Zero });
        Assert.True(result.Failed);
        Assert.Contains("LiveAlarmCacheReconcileInterval", result.FailureMessage);
    }

    [Fact]
    public void ZeroLiveAlarmCacheSeedConcurrency_IsRejected()
    {
        var result = Validate(new CommunicationOptions { LiveAlarmCacheSeedConcurrency = 0 });
        Assert.True(result.Failed);
        Assert.Contains("LiveAlarmCacheSeedConcurrency", result.FailureMessage);
    }

    [Fact]
    public void ExcessiveLiveAlarmCacheSeedConcurrency_IsRejected()
    {
        var result = Validate(new CommunicationOptions { LiveAlarmCacheSeedConcurrency = 65 });
        Assert.True(result.Failed);
        Assert.Contains("LiveAlarmCacheSeedConcurrency", result.FailureMessage);
    }

    [Fact]
    public void ZeroLiveAlarmCacheMaxSubscribersPerSite_IsRejected()
    {
        var result = Validate(new CommunicationOptions { LiveAlarmCacheMaxSubscribersPerSite = 0 });
        Assert.True(result.Failed);
        Assert.Contains("LiveAlarmCacheMaxSubscribersPerSite", result.FailureMessage);
    }

    // ── R2 T10: live-delta publish-coalescing window (N6) ────────────────────────

    [Fact]
    public void ZeroLiveAlarmCachePublishCoalesce_IsValid()
    {
        // Zero = publish per delta (legacy behavior).
        var result = Validate(new CommunicationOptions { LiveAlarmCachePublishCoalesce = TimeSpan.Zero });
        Assert.True(result.Succeeded, result.FailureMessage);
    }

    [Fact]
    public void NegativeLiveAlarmCachePublishCoalesce_IsRejected()
    {
        var result = Validate(new CommunicationOptions { LiveAlarmCachePublishCoalesce = TimeSpan.FromMilliseconds(-1) });
        Assert.True(result.Failed);
        Assert.Contains("LiveAlarmCachePublishCoalesce", result.FailureMessage);
    }

    // ── T1A.3: gRPC central transport endpoints (required only when selected) ────

    [Fact]
    public void GrpcTransport_WithNoEndpoints_IsRejected()
    {
        var result = Validate(new CommunicationOptions
        {
            CentralTransport = CentralTransportMode.Grpc,
            CentralGrpcEndpoints = new List<string>(),
        });
        Assert.True(result.Failed);
        Assert.Contains("CentralGrpcEndpoints", result.FailureMessage);
    }

    [Fact]
    public void GrpcTransport_WithBlankEndpoint_IsRejected()
    {
        var result = Validate(new CommunicationOptions
        {
            CentralTransport = CentralTransportMode.Grpc,
            CentralGrpcEndpoints = new List<string> { "   " },
        });
        Assert.True(result.Failed);
        Assert.Contains("CentralGrpcEndpoints", result.FailureMessage);
    }

    [Fact]
    public void GrpcTransport_WithEndpoints_IsValid()
    {
        var result = Validate(new CommunicationOptions
        {
            CentralTransport = CentralTransportMode.Grpc,
            CentralGrpcEndpoints = new List<string>
            {
                "http://scadabridge-central-a:8083",
                "http://scadabridge-central-b:8083",
            },
        });
        Assert.True(result.Succeeded, result.FailureMessage);
    }

    [Fact]
    public void AkkaTransport_IgnoresMissingGrpcEndpoints()
    {
        // The default transport must not be forced to declare gRPC endpoints it never dials.
        var result = Validate(new CommunicationOptions
        {
            CentralTransport = CentralTransportMode.Akka,
            CentralGrpcEndpoints = new List<string>(),
        });
        Assert.True(result.Succeeded, result.FailureMessage);
    }
}