using Microsoft.Extensions.Options;

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

/// <summary>
/// HealthMonitoring-014 regression: <see cref="HealthMonitoringOptions"/> intervals
/// are fed straight into <c>new PeriodicTimer(...)</c>, which throws
/// <see cref="ArgumentOutOfRangeException"/> for a zero/negative period. A
/// misconfigured <c>appsettings.json</c> must be rejected by an
/// <see cref="IValidateOptions{TOptions}"/> with a clear, key-naming message
/// rather than crashing the hosted service with an opaque exception.
/// </summary>
public class HealthMonitoringOptionsValidatorTests
{
    private static ValidateOptionsResult Validate(HealthMonitoringOptions options) =>
        new HealthMonitoringOptionsValidator().Validate(Options.DefaultName, options);

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

    [Fact]
    public void ZeroReportInterval_IsRejected()
    {
        var result = Validate(new HealthMonitoringOptions { ReportInterval = TimeSpan.Zero });

        Assert.True(result.Failed);
        Assert.Contains("ReportInterval", result.FailureMessage);
    }

    [Fact]
    public void NegativeReportInterval_IsRejected()
    {
        var result = Validate(new HealthMonitoringOptions { ReportInterval = TimeSpan.FromSeconds(-1) });

        Assert.True(result.Failed);
        Assert.Contains("ReportInterval", result.FailureMessage);
    }

    [Fact]
    public void ZeroOfflineTimeout_IsRejected()
    {
        var result = Validate(new HealthMonitoringOptions { OfflineTimeout = TimeSpan.Zero });

        Assert.True(result.Failed);
        Assert.Contains("OfflineTimeout", result.FailureMessage);
    }

    [Fact]
    public void ZeroCentralOfflineTimeout_IsRejected()
    {
        var result = Validate(new HealthMonitoringOptions { CentralOfflineTimeout = TimeSpan.Zero });

        Assert.True(result.Failed);
        Assert.Contains("CentralOfflineTimeout", result.FailureMessage);
    }

    [Fact]
    public void CentralOfflineTimeout_ShorterThanOfflineTimeout_IsRejected()
    {
        var result = Validate(new HealthMonitoringOptions
        {
            OfflineTimeout = TimeSpan.FromSeconds(60),
            CentralOfflineTimeout = TimeSpan.FromSeconds(30)
        });

        Assert.True(result.Failed);
        Assert.Contains("CentralOfflineTimeout", result.FailureMessage);
    }

    [Fact]
    public void ZeroMetricsStaleTimeout_IsRejected()
    {
        var result = Validate(new HealthMonitoringOptions { MetricsStaleTimeout = TimeSpan.Zero });

        Assert.True(result.Failed);
        Assert.Contains("MetricsStaleTimeout", result.FailureMessage);
    }

    [Fact]
    public void MetricsStaleTimeout_ShorterThanReportInterval_IsRejected()
    {
        // A stale window shorter than one report interval flags every site.
        var result = Validate(new HealthMonitoringOptions
        {
            ReportInterval = TimeSpan.FromSeconds(30),
            MetricsStaleTimeout = TimeSpan.FromSeconds(10)
        });

        Assert.True(result.Failed);
        Assert.Contains("MetricsStaleTimeout", result.FailureMessage);
    }
}
