using System.Globalization;

namespace ZB.MOM.WW.OtOpcUa.Runtime.Tests.Harness;

/// <summary>
///     The Akka TestKit time-dilation factor for this run, from the <c>AKKA_TEST_TIMEFACTOR</c> environment
///     variable (unset ⇒ 1, Akka's own default).
/// </summary>
/// <remarks>
///     <para>
///         <c>akka.test.timefactor</c> is Akka's sanctioned answer to "this machine is slower than the one
///         the timeouts were sized on": TestKit multiplies every <c>ExpectMsg</c> / <c>ExpectTerminated</c> /
///         <c>AwaitAssert</c> / <c>AwaitCondition</c> / <c>ExpectNoMsg</c> duration by it — explicit
///         durations included (<c>RemainingOrDilated</c>). The Gitea CI leg sets it (#606): the whole
///         solution runs there at once on the CI runner, and a long tail of 2–8 s presence budgets that
///         never fail locally each failed in roughly one run in eight, a different test each time — a
///         distribution, not a defect, exactly the shape Gitea #500 hit inside this assembly alone.
///     </para>
///     <para>
///         Dilation cannot make a broken assertion pass: a presence wait still fails, just later, and an
///         absence window only gets LONGER (a stronger check). It does not reach <c>Ask</c> timeouts or
///         plain <c>Task.WaitAsync</c> budgets — those are sized from <c>PresenceBudget</c> instead.
///     </para>
/// </remarks>
internal static class TestTimeFactor
{
    /// <summary>The environment variable the CI workflow sets.</summary>
    public const string EnvironmentVariable = "AKKA_TEST_TIMEFACTOR";

    /// <summary>The factor in effect: the variable's value when it parses to a number ≥ 1, else 1.</summary>
    public static double Value { get; } =
        double.TryParse(Environment.GetEnvironmentVariable(EnvironmentVariable), NumberStyles.Float,
            CultureInfo.InvariantCulture, out var f) && f >= 1 ? f : 1;

    /// <summary>A HOCON line setting <c>akka.test.timefactor</c>, to append to a test config.</summary>
    public static string Hocon =>
        "\nakka.test.timefactor = " + Value.ToString(CultureInfo.InvariantCulture) + "\n";
}