using Opc.Ua;
using Shouldly;
using Xunit;

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

/// <summary>Review 01 P6 — the SDK request and transport quotas are configurable (<c>OpcUa:Quotas:*</c>) and
/// default to exactly what used to be hard-coded.</summary>
public sealed class OpcUaApplicationHostQuotaTests
{
    [Fact]
    public void Default_request_quotas_are_the_former_hard_coded_values()
    {
        var config = new ServerConfiguration();
        OpcUaApplicationHost.ApplyRequestQuotas(config, new OpcUaQuotaOptions());

        config.MinRequestThreadCount.ShouldBe(5);
        config.MaxRequestThreadCount.ShouldBe(100);
        config.MaxQueuedRequestCount.ShouldBe(200);
    }

    [Fact]
    public void Configured_request_quotas_are_applied()
    {
        var config = new ServerConfiguration();
        OpcUaApplicationHost.ApplyRequestQuotas(config, new OpcUaQuotaOptions
        {
            MinRequestThreadCount = 8, MaxRequestThreadCount = 250, MaxQueuedRequestCount = 1000,
        });

        config.MinRequestThreadCount.ShouldBe(8);
        config.MaxRequestThreadCount.ShouldBe(250);
        config.MaxQueuedRequestCount.ShouldBe(1000);
    }

    [Fact]
    public void Unset_transport_quotas_keep_the_sdk_defaults()
    {
        var sdkDefault = new TransportQuotas();
        var built = OpcUaApplicationHost.BuildTransportQuotas(new OpcUaQuotaOptions());

        built.OperationTimeout.ShouldBe(sdkDefault.OperationTimeout);
        built.MaxStringLength.ShouldBe(sdkDefault.MaxStringLength);
        built.MaxByteStringLength.ShouldBe(sdkDefault.MaxByteStringLength);
        built.MaxArrayLength.ShouldBe(sdkDefault.MaxArrayLength);
        built.MaxMessageSize.ShouldBe(sdkDefault.MaxMessageSize);
        built.MaxBufferSize.ShouldBe(sdkDefault.MaxBufferSize);
        built.ChannelLifetime.ShouldBe(sdkDefault.ChannelLifetime);
        built.SecurityTokenLifetime.ShouldBe(sdkDefault.SecurityTokenLifetime);
    }

    [Fact]
    public void Configured_transport_quotas_replace_only_what_is_set()
    {
        var sdkDefault = new TransportQuotas();
        var built = OpcUaApplicationHost.BuildTransportQuotas(new OpcUaQuotaOptions
        {
            MaxMessageSize = 8 * 1024 * 1024, OperationTimeoutMs = 45_000, MaxArrayLength = 1_000_000,
        });

        built.MaxMessageSize.ShouldBe(8 * 1024 * 1024);
        built.OperationTimeout.ShouldBe(45_000);
        built.MaxArrayLength.ShouldBe(1_000_000);
        built.MaxStringLength.ShouldBe(sdkDefault.MaxStringLength);
        built.ChannelLifetime.ShouldBe(sdkDefault.ChannelLifetime);
    }

    [Fact]
    public void History_read_batch_cap_default_scales_with_the_machine()
    {
        OtOpcUaNodeManager.DefaultMaxConcurrentHistoryReadBatches
            .ShouldBe(Math.Clamp(Environment.ProcessorCount * 2, 4, 16));
    }
}