using Microsoft.Extensions.Logging.Abstractions;
using ZB.MOM.WW.MxGateway.Server.Configuration;
using ZB.MOM.WW.MxGateway.Server.Grpc;

namespace ZB.MOM.WW.MxGateway.Server.Sessions;

/// <summary>
///     Dependencies a <see cref="GatewaySession"/> needs to construct and own its
///     <see cref="SessionEventDistributor"/>. Bundled so the session constructor stays a
///     single optional parameter rather than four, and so unit tests that build a session
///     directly get a working distributor from <see cref="Default"/> without wiring DI.
/// </summary>
/// <param name="Mapper">
///     Maps worker IPC <c>WorkerEvent</c> frames to public <c>MxEvent</c>s. The distributor
///     pump applies this once per event in worker order, mirroring the mapping
///     <c>EventStreamService.ProduceEventsAsync</c> used before Task 4.
/// </param>
/// <param name="EventOptions">
///     Supplies the distributor's per-subscriber queue capacity and replay ring-buffer
///     bounds (<see cref="EventOptions.QueueCapacity"/>,
///     <see cref="EventOptions.ReplayBufferCapacity"/>,
///     <see cref="EventOptions.ReplayRetentionSeconds"/>).
/// </param>
/// <param name="DistributorLogger">Logger for the distributor pump lifecycle.</param>
/// <param name="TimeProvider">Clock used to timestamp and age-evict replay entries.</param>
public sealed record SessionEventStreaming(
    MxAccessGrpcMapper Mapper,
    EventOptions EventOptions,
    ILogger<SessionEventDistributor> DistributorLogger,
    TimeProvider TimeProvider)
{
    /// <summary>
    ///     Defaults used when a session is constructed without explicit streaming
    ///     dependencies (unit tests). Uses a fresh mapper, default event options, a no-op
    ///     logger, and the system clock.
    /// </summary>
    public static SessionEventStreaming Default { get; } = new(
        new MxAccessGrpcMapper(),
        new EventOptions(),
        NullLogger<SessionEventDistributor>.Instance,
        TimeProvider.System);
}