using SVSim.BattleNode.Protocol;
using SVSim.BattleNode.Sessions.Participants; // IHasHandshakePhase

namespace SVSim.BattleNode.Sessions.Dispatch;

/// <summary>Everything a handler reads or mutates for one inbound frame. <see cref="A"/>/<see cref="B"/>
/// are the session's positional participants (preserved so handlers that iterate participants in a
/// stable order — e.g. the mulligan barrier — match the legacy switch byte-for-byte). <see cref="From"/>
/// is the sender; <see cref="Other"/> is the non-sender.</summary>
internal sealed class FrameDispatchContext
{
    internal required IBattleParticipant A { get; init; }
    internal required IBattleParticipant B { get; init; }
    internal required IBattleParticipant From { get; init; }
    internal required IBattleParticipant Other { get; init; }
    internal required MsgEnvelope Env { get; init; }
    internal required BattleType Type { get; init; }
    internal required string BattleId { get; init; }
    internal required BattleSessionState State { get; init; }

    /// <summary>The dispatching participant's handshake phase (null for a non-IHasHandshakePhase
    /// participant, e.g. NoOpBot). Setting it advances the sender.</summary>
    internal HandshakePhase? SenderPhase
    {
        get => (From as IHasHandshakePhase)?.Phase;
        set { if (From is IHasHandshakePhase p && value is { } v) p.Phase = v; }
    }

    /// <summary>Both participants have completed the handshake. Reads A/B (not From/Other) so the
    /// result is identical regardless of which side sent the frame — matches legacy BothAfterReady.</summary>
    internal bool BothAfterReady() =>
        (A as IHasHandshakePhase)?.Phase == HandshakePhase.AfterReady &&
        (B as IHasHandshakePhase)?.Phase == HandshakePhase.AfterReady;
}