namespace ZB.MOM.WW.OtOpcUa.Core.Abstractions;

/// <summary>
///     Stability tier of a driver type. Determines which cross-cutting runtime protections
///     apply — per-tier retry defaults, memory-tracking thresholds, and whether out-of-process
///     supervision with process-level recycle is in play.
/// </summary>
/// <remarks>
///     Per <c>docs/v2/driver-stability.md</c> §2-4 and <c>docs/v2/plan.md</c> decisions #63-74.
///
///     <list type="bullet">
///         <item><b>A</b> — managed, known-good SDK; low blast radius. In-process. Fast retries.
///             Examples: OPC UA Client (OPCFoundation stack), S7 (S7NetPlus).</item>
///         <item><b>B</b> — native or semi-trusted SDK with an in-process footprint. Examples: Modbus.</item>
///         <item><b>C</b> — unmanaged SDK with COM/STA constraints, leak risk, or other out-of-process
///             requirements. Must run as a separate Host process behind a Proxy with a supervisor that
///             can recycle the process on hard-breach. Example: Galaxy (MXAccess COM).</item>
///     </list>
///
///     <para>Process-kill protections (<c>MemoryRecycle</c>, <c>ScheduledRecycleScheduler</c>) are
///     Tier C only per decisions #73-74 and #145 — killing an in-process Tier A/B driver also kills
///     every OPC UA session and every co-hosted driver, blast-radius worse than the leak.</para>
/// </remarks>
public enum DriverTier
{
    /// <summary>Managed SDK, in-process, low blast radius.</summary>
    A,

    /// <summary>Native or semi-trusted SDK, in-process.</summary>
    B,

    /// <summary>Unmanaged SDK, out-of-process required with Proxy+Host+Supervisor.</summary>
    C,
}