namespace MoShiro.Backend.Analysis;

/// <summary>连接建立、长连接、UDP 压测（udp_train）的指标。</summary>
public static class SessionMetrics
{
    private static readonly string[] s_conn = ["connect.conn"];
    private static readonly string[] s_hold = ["hold.hold"];
    private static readonly string[] s_train = ["udp_train.pkt"];

    public static readonly MetricDef ConnectSuccess = new(
        "connect.success", AccKind.Ratio, s_conn, Ops.OutcomeRatio(ConnectOutcome.Ok), "Connect success", "Share of connection attempts that completed.", Better.Higher,
        [new MetricExport("connect.success", Stat.Pct, Unit.Pct, 99, 90)]);

    public static readonly MetricDef ConnectTcp = Metric.Histogram(
        "connect.tcp_ms", s_conn, Ops.PhaseMs("tcp_us"), "TCP connect time", "Time to establish the TCP connection.", Unit.Ms, [Stat.P95], good: 100, poor: 400);

    public static readonly MetricDef ConnectTls = Metric.Histogram(
        "connect.tls_ms", s_conn, Ops.PhaseMs("tls_us"), "TLS handshake time", "Time for the TLS handshake after TCP is up.", Unit.Ms, [Stat.P95], good: 200, poor: 800);

    public static readonly MetricDef FailTimeout = Metric.Counter(
        "connect.fail.timeout", s_conn, Ops.OutcomeCount(ConnectOutcome.Timeout), "Connect timeouts", "Attempts that timed out.", new MetricExport("connect.fail.timeout", Stat.Count, Unit.Count));

    public static readonly MetricDef FailReset = Metric.Counter(
        "connect.fail.rst", s_conn, Ops.OutcomeCount(ConnectOutcome.Reset), "Connect resets", "Attempts answered with a reset.", new MetricExport("connect.fail.rst", Stat.Count, Unit.Count));

    public static readonly MetricDef FailTls = Metric.Counter(
        "connect.fail.tls", s_conn, Ops.OutcomeCount(ConnectOutcome.TlsAlert), "TLS failures", "Attempts that ended in a TLS alert.", new MetricExport("connect.fail.tls", Stat.Count, Unit.Count));

    public static readonly MetricDef HoldResets = Metric.Counter(
        "hold.resets", s_hold, Ops.HoldEvents(HoldEvent.Reset), "Held connection resets", "Times the held connection was reset.", new MetricExport("hold.resets.per_h", Stat.PerHour, Unit.PerHour, 0.5, 4));

    public static readonly MetricDef HoldLifetime = Metric.Max(
        "hold.lifetime", s_hold, Ops.HoldLifetime, "Longest connection lifetime", "Longest observed lifetime of the held connection (ms).", Unit.Ms, "hold.lifetime_max", Better.Higher);

    public static readonly MetricDef TrainLoss = Metric.Ratio(
        "train.loss", s_train, Ops.TrainLoss, "Train loss", "Loss of a fixed-rate UDP stream.", good: 1, poor: 10);

    public static readonly MetricDef TrainJitter = Metric.Histogram(
        "train.jitter", s_train, Ops.TrainJitter, "Train jitter", "One-way delay variation of a fixed-rate UDP stream.", Unit.Ms, [Stat.P95], good: 3, poor: 20);

    public static readonly MetricDef TrainRate = Metric.Histogram(
        "train.rate", s_train, Ops.TrainRate, "Train rate", "Delivered rate of a fixed-rate UDP stream per second.", Unit.Mbps, [Stat.P50, Stat.Mean], Better.Higher);

    public static readonly MetricDef SamplesConnect = Metric.Counter(
        "n.connect", s_conn, Ops.RowCount, "connect samples", "Number of connection attempts.", new MetricExport("n.connect", Stat.Count, Unit.Count), Better.None);
}