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

/// <summary>
/// Regression coverage. <see cref="ISiteEventLogger.FailedWriteCount"/>
/// is a cumulative (point-in-time) counter. A periodic
/// <c>SiteEventLogFailureCountReporter</c> hosted service polls the count and
/// pushes it into the collector via
/// <see cref="ISiteHealthCollector.SetSiteEventLogWriteFailures"/> so the next
/// <see cref="ISiteHealthCollector.CollectReport"/> includes it in the report
/// payload as <c>SiteEventLogWriteFailures</c>. Unlike the per-interval
/// SiteAuditWriteFailures counter, this value is NOT reset on collect — it
/// carries forward whatever the most recent poller push delivered.
/// </summary>
public class SiteEventLogWriteFailuresMetricTests
{
    private readonly SiteHealthCollector _collector = new();

    /// <summary>Verifies that a count that was set appears in the collected report.</summary>
    [Fact]
    public void Set_Then_CollectReport_IncludesCount()
    {
        _collector.SetSiteEventLogWriteFailures(17L);

        var report = _collector.CollectReport("site-1");

        Assert.Equal(17L, report.SiteEventLogWriteFailures);
    }

    /// <summary>Verifies that the report payload includes the site event log write failure count, defaulting to zero.</summary>
    [Fact]
    public void Report_Payload_Includes_SiteEventLogWriteFailures_AsZeroByDefault()
    {
        var report = _collector.CollectReport("site-1");

        Assert.Equal(0L, report.SiteEventLogWriteFailures);
    }

    /// <summary>Verifies that collecting a report does not reset the site event log write failure count.</summary>
    [Fact]
    public void CollectReport_DoesNotReset_SiteEventLogWriteFailures()
    {
        // This is a point-in-time cumulative count — successive CollectReport
        // calls before the next poller tick MUST carry forward the same value
        // rather than resetting to zero (which would falsely indicate no failures
        // between the two reports).
        _collector.SetSiteEventLogWriteFailures(42L);

        var first = _collector.CollectReport("site-1");
        var second = _collector.CollectReport("site-1");

        Assert.Equal(42L, first.SiteEventLogWriteFailures);
        Assert.Equal(42L, second.SiteEventLogWriteFailures);
    }

    /// <summary>Verifies that setting the count overwrites the previous value.</summary>
    [Fact]
    public void Set_Overwrites_Previous_Value()
    {
        _collector.SetSiteEventLogWriteFailures(5L);
        _collector.SetSiteEventLogWriteFailures(9L);

        var report = _collector.CollectReport("site-1");

        Assert.Equal(9L, report.SiteEventLogWriteFailures);
    }
}