namespace MoShiro.Protocol;

/// <summary>
/// Kind 目录。新增一种采集方法 = 在这里加一个静态字段并放进 <see cref="All"/>；
/// 参数一律用 <see cref="P"/> 声明默认值和上下限。
/// </summary>
public static class Kinds
{
    private static readonly string[] s_directions = ["fwd", "rev", "bidir"];

    /// <summary>这个任务可能达到的最高探测频率（Hz）：自适应时是 <c>rate_max_hz</c>，否则是固定的 <c>rate_hz</c>。预算、限速和准入都按它算。</summary>
    public static long PeakRateHz(string kindId, ParamValues values) =>
        (kindId is "udp_echo" or "tcp_echo") && values.GetBool("adaptive") ? Math.Max(values.GetInt("rate_max_hz"), values.GetInt("rate_min_hz")) : values.GetInt("rate_hz");

    private static readonly StreamSpec s_echoMsg = new(
        "msg",
        [
            Col.Seq("seq"), Col.U16("size"), Col.U16("w"),
            Col.TsDialer("t1"), Col.TsListener("t2", nullable: true), Col.TsListener("t3", nullable: true), Col.TsDialer("t4", nullable: true),
        ],
        Side.Dialer,
        "seq");

    private static readonly StreamSpec s_tcpInfo = new(
        "tcp_info",
        [
            Col.TsLocal("ts"), Col.U8("side"), Col.U32("srtt_us"), Col.U32("rttvar_us"), Col.U32("cwnd"),
            Col.U32("retrans_total"), Col.U32("segs_out"), Col.U64("bytes_acked"),
            new ColumnSpec("conn", ColumnType.U64, ColumnEnc.Plain, true),
        ],
        Union: true);

    public static readonly KindSpec UdpEcho = new(
        "udp_echo",
        "QUIC Datagram echo",
        "Fixed-rate QUIC Datagram echo with four timestamps per packet.",
        Scope.Line,
        new BlockSet("quic_datagram", "fixed", "fixed", "echo", []),
        [
            P.Bool("adaptive", true, "Adapt the probe rate to the loss rate: low when the line is quiet, up to rate_max_hz when it loses packets, exponential back-off when it is unreachable."),
            P.Int("rate_hz", 10, 1, 200, "Hz", "Fixed rate, used when adaptive is false."),
            P.Int("rate_min_hz", 2, 1, 200, "Hz"),
            P.Int("rate_max_hz", 10, 1, 200, "Hz", "Highest rate, and the reference grid for sample weights."),
            P.Number("tau_pct", 0.2, 0.01, 5, "%", "Loss rate a quiet line has to be able to prove below, at 95% confidence."),
            P.Number("rtt_tol_pct", 2, 0.1, 20, "%", "Half-width of the 95% confidence interval of the RTT p99 a quiet line has to keep, as a share of p99 (never below 0.3 ms)."),
            P.Int("size", 64, 44, 1400, "B"),
            P.Int("port", 7443, 1, 65535),
        ],
        [s_echoMsg],
        p => Bandwidth.UdpEcho(PeakRateHz("udp_echo", p), p.GetInt("size")));

    public static readonly KindSpec UdpTrain = new(
        "udp_train",
        "QUIC Datagram train",
        "Fixed-rate or laddered one-way QUIC Datagram stream (Agent to 拨号方) for loss and delay variation under load.",
        Scope.Line,
        new BlockSet("quic_datagram", "ladder", "fixed", "sink", []),
        [
            P.Number("mbps", 10, 0.1, 1000, "Mbit/s"),
            P.Int("size", 1250, 200, 1400, "B"),
            P.Int("duration_s", 10, 1, 120, "s"),
            P.Enum("direction", "rev", s_directions),
            P.Int("port", 7443, 1, 65535),
        ],
        [
            new StreamSpec("pkt", [Col.Seq("seq"), Col.U16("size"), Col.TsListener("t_send"), Col.TsDialer("t_recv", nullable: true)], Side.Listener, "seq"),
            new StreamSpec("step", [Col.U16("index"), Col.U32("mbps"), Col.TsDialer("start_ts"), Col.TsDialer("end_ts")]),
        ],
        p => (long)(p.GetNumber("mbps") * 1_000_000));

    public static readonly KindSpec TcpEcho = new(
        "tcp_echo",
        "TCP echo",
        "Small TCP messages echoed with four timestamps, plus periodic kernel tcp_info samples.",
        Scope.Line,
        new BlockSet("tcp", "fixed", "uniform", "echo", ["tcp_info"]),
        [
            P.Bool("adaptive", true, "Adapt the echo rate: as low as the loss bound and the RTT percentile precision allow when the line is quiet, the maximum when it is not, back-off when it stalls."),
            P.Int("rate_hz", 20, 1, 200, "Hz", "Fixed rate, used when adaptive is false."),
            P.Int("rate_min_hz", 2, 1, 200, "Hz"),
            P.Int("rate_max_hz", 20, 1, 200, "Hz", "Highest rate, and the reference grid for sample weights."),
            P.Number("tau_pct", 0.2, 0.01, 5, "%", "Share of retransmitted segments a quiet line has to be able to prove below, at 95% confidence."),
            P.Number("rtt_tol_pct", 2, 0.1, 20, "%", "Half-width of the 95% confidence interval of the RTT p99 a quiet line has to keep, as a share of p99 (never below 0.3 ms)."),
            P.Int("min", 32, 16, 1400, "B"),
            P.Int("max", 64, 16, 1400, "B"),
            P.Int("tcp_info_ms", 1000, 10, 1000, "ms"),
            P.Int("port", 7444, 1, 65535),
            P.Bool("tls", false),
        ],
        [s_echoMsg, s_tcpInfo],
        p => Bandwidth.TcpEcho(PeakRateHz("tcp_echo", p), p.GetInt("max")));

    public static readonly KindSpec TcpBulk = new(
        "tcp_bulk",
        "TCP bulk",
        "Bulk TCP transfer on several streams with periodic byte counters and tcp_info.",
        Scope.Line,
        new BlockSet("tcp", "fixed", "fixed", "source", ["tcp_info"]),
        [
            P.Int("streams", 4, 1, 16),
            P.Int("duration_s", 4, 1, 120, "s"),
            P.Enum("direction", "rev", s_directions),
            P.Int("sample_ms", 100, 20, 1000, "ms"),
            P.Int("port", 7444, 1, 65535),
            P.Bool("tls", true),
        ],
        [
            new StreamSpec("bytes", [Col.TsDialer("ts"), Col.U8("conn"), Col.U64("bytes")]),
            s_tcpInfo,
        ],
        _ => 0);

    public static readonly KindSpec Connect = new(
        "connect",
        "Connect",
        "Repeated TCP and TLS connection establishment with per-phase timings and outcome.",
        Scope.Line | Scope.Target,
        new BlockSet("tcp", "fixed", "fixed", "connect", []),
        [
            P.Int("per_minute", 6, 1, 60),
            P.Bool("tls", true),
            P.Int("timeout_ms", 5000, 500, 30000, "ms"),
            P.Int("port", 7444, 1, 65535),
        ],
        [
            new StreamSpec(
                "conn",
                [Col.Seq("attempt"), Col.TsDialer("ts"), Col.U32("tcp_us", nullable: true), Col.U32("tls_us", nullable: true), Col.U8("outcome")]),
        ],
        p => p.GetInt("per_minute") * 4000 / 60);

    public static readonly KindSpec Hold = new(
        "hold",
        "Hold",
        "A long-lived TLS connection with periodic heartbeats; records resets and lifetime.",
        Scope.Line,
        new BlockSet("tls", "fixed", "fixed", "hold", []),
        [
            P.Int("heartbeat_s", 30, 5, 300, "s"),
            P.Int("port", 7444, 1, 65535),
        ],
        [
            new StreamSpec("hold", [Col.TsDialer("ts"), Col.U8("event"), Col.U32("lifetime_ms")]),
        ],
        p => 2000 / Math.Max(1, p.GetInt("heartbeat_s")) * 8);

    public static readonly KindSpec IcmpEcho = new(
        "icmp_echo",
        "ICMP echo",
        "拨号方 or Agent side ICMP echo to a target address.",
        Scope.Target,
        new BlockSet("icmp", "fixed", "fixed", "echo", []),
        [
            P.Int("rate_hz", 1, 1, 20, "Hz"),
            P.Int("size", 64, 44, 1400, "B"),
        ],
        [
            new StreamSpec("msg", [Col.Seq("seq"), Col.U16("size"), Col.TsLocal("t1"), new ColumnSpec("t4", ColumnType.I64, ColumnEnc.Delta, true, ColumnRole.TsLocal)]),
        ],
        p => Bandwidth.UdpEcho(p.GetInt("rate_hz"), p.GetInt("size")));

    public static readonly IReadOnlyList<KindSpec> All = [UdpEcho, UdpTrain, TcpEcho, TcpBulk, Connect, Hold, IcmpEcho];

    public static KindSpec? Find(string id)
    {
        foreach (KindSpec kind in All)
        {
            if (kind.Id == id)
            {
                return kind;
            }
        }

        return null;
    }
}