using ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport.Cip;

namespace ZB.MOM.WW.OtOpcUa.Driver.AbCip;

/// <summary>
///     Maps <see cref="AbCipTagCreateParams"/> onto the native transport's connection identity and
///     settings. Shared by the native tag runtime, enumerator and template reader so every handle on
///     one device leases the same pooled connection.
/// </summary>
internal static class NativeAbCipDevice
{
    /// <summary>The EtherNet/IP default TCP port, used when no usable port was configured.</summary>
    internal const int DefaultPort = 44818;

    /// <summary>The <c>plc=</c> attribute of the Micro800 family profile.</summary>
    private const string Micro800Attribute = "micro800";

    /// <summary>The pool key: one CIP connection per <c>(host, port, cipPath, plcAttribute)</c>.</summary>
    /// <param name="p">The tag creation parameters.</param>
    /// <returns>The device key.</returns>
    public static DeviceKey Key(AbCipTagCreateParams p) =>
        new(p.Gateway, p.Port > 0 ? p.Port : DefaultPort, p.CipPath, p.LibplctagPlcAttribute);

    /// <summary>The connection settings for the device <paramref name="p"/> addresses.</summary>
    /// <param name="p">The tag creation parameters.</param>
    /// <returns>The connection options.</returns>
    public static ConnectionOptions Options(AbCipTagCreateParams p) => new()
    {
        Routing = RoutingFor(p),
        Timeout = p.Timeout,
        ConnectionSize = p.ConnectionSize,
        AllowPacking = p.AllowPacking,
    };

    /// <summary>
    ///     How requests reach the controller's message router.
    /// </summary>
    /// <remarks>
    ///     Micro800 is <b>always</b> <see cref="CipRouting.Connected"/> with an empty route, even though its
    ///     family profile says <c>SupportsConnectedMessaging: false</c>: libplctag opens a Large Forward
    ///     Open with connection path <c>20 02 24 01</c> and reads connected (Captures/micro800-read-dint.hex,
    ///     Captures/README.md "Routing observed"; ruling R12-1 — the capture beats the profile flag).
    ///     Every other family follows the profile: connected-capable ⇒ Forward Open; otherwise
    ///     Unconnected Send when a route is configured, bare SendRRData when it is not.
    /// </remarks>
    /// <param name="p">The tag creation parameters.</param>
    /// <returns>The routing mode.</returns>
    internal static CipRouting RoutingFor(AbCipTagCreateParams p)
    {
        if (string.Equals(p.LibplctagPlcAttribute, Micro800Attribute, StringComparison.OrdinalIgnoreCase))
            return CipRouting.Connected;
        if (p.UseConnectedMessaging) return CipRouting.Connected;
        return string.IsNullOrWhiteSpace(p.CipPath) ? CipRouting.Direct : CipRouting.UnconnectedSend;
    }
}