SVSimServer/SVSim.BattleNode/Sessions/Dispatch/Handlers/PlayActionsHandler.cs

using SVSim.BattleNode.Protocol;
using SVSim.BattleNode.Protocol.Bodies;

namespace SVSim.BattleNode.Sessions.Dispatch.Handlers;

/// <summary>PvP PlayActions translator. Synthesizes the opponent-facing knownList from the sender's
/// idx->cardId map + the orderList move op, renames targetList -> oppoTargetList, drops orderList,
/// and forwards a stripped keyAction for choice/Discover plays ({type,cardId}; selectCard dropped
/// for a hidden open:0 pick). Token plays resolve their cardId from add ops (concrete tokens),
/// keyAction.selectCard (choice picks), or a baseIdx copy resolved against the side's map — all mined
/// on earlier (or the same) frames; an un-generated token idx still degrades to {playIdx,type}
/// (no knownList). Bot drop (no rule).</summary>
internal sealed class PlayActionsHandler : IFrameHandler
{
    public IReadOnlyList<DispatchRoute> Handle(FrameDispatchContext ctx)
    {
        if (!ctx.BothSidesAfterReady())
            return Array.Empty<DispatchRoute>();

        var entries = (ctx.Env.Body as RawBody)?.Entries ?? new Dictionary<string, object?>();
        var playIdx = (int)KnownListBuilder.AsLong(entries.GetValueOrDefault(WireKeys.PlayIdx));
        var type = (int)KnownListBuilder.AsLong(entries.GetValueOrDefault(WireKeys.Type));

        var orderList = entries.GetValueOrDefault(WireKeys.OrderList);
        var keyAction = entries.GetValueOrDefault(WireKeys.KeyAction);

        // Mine generated-token identities from this frame's add ops into the right side's idx->cardId
        // map (isSelf:1 → sender; isSelf:0 → opponent, a cross-side gift), so a token played in a LATER
        // frame resolves its cardId — by whichever side ends up playing it (bullet-3 audit F1).
        ctx.State.RecordTokensFrom(ctx.From, ctx.Other, orderList);

        // Choice/Discover-into-hand: the chosen cardId rides keyAction.selectCard (the orderList's
        // choiceAdd carries candidates only). Record idx->chosenCardId now so the later play reveals it.
        ctx.State.RecordChoicePicksFrom(ctx.From, ctx.Other, orderList, keyAction);

        // Copy/clone tokens: card:{baseIdx} points at a card in the actor's own index space; resolve it
        // against that side's map and record copyIdx->cardId so the later play reveals it. Ordered after
        // the plain/choice mining so a same-frame copy of a just-added token resolves against the live map.
        ctx.State.RecordCopyTokensFrom(ctx.From, ctx.Other, orderList);

        var deckMap = ctx.State.GetOrSeedDeckMap(ctx.From);
        // The ENGINE-RESOLVED play-time cost (M-HC-3a). The conductor's ShadowIngest already ran
        // engine.Receive for THIS frame before this handler runs, so the engine has resolved the play and
        // PlayedCardCost reads the discounted cost it actually charged (spellboost + board modifiers folded
        // in BY CONSTRUCTION — no bookkeeping). Sender's seat == ctx.A (BattleSession.ShadowIngest uses the
        // same ReferenceEquals(from, A) mapping). Degrades to 0 when the engine isn't owned/ready for this
        // session (single-active-engine gate) so a non-engine session never crashes.
        bool senderSeat = ReferenceEquals(ctx.From, ctx.A);
        int playedCost = ctx.Engine.PlayedCardCost(senderSeat, playIdx, fallback: 0);

        // Spellboost count still rides the played card's knownList (prod-faithful; Task 6 retires this
        // bookkeeping now that cost is engine-sourced). Read the CURRENT map (state before this frame's
        // grant) for the emit, then fold THIS frame's alter ops in afterwards — a play that grants
        // spellboost (e.g. Fate's Hand) targets the REST of the hand, not the card just played.
        var played = KnownListBuilder.BuildPlayedCard(
            deckMap, playIdx, orderList, ctx.State.GetSpellboostMap(ctx.From), cost: playedCost);
        ctx.State.RecordSpellboostFrom(ctx.From, ctx.Other, orderList);
        var oppoTargets = KnownListBuilder.RenameTargets(entries.GetValueOrDefault(WireKeys.TargetList));

        // Deck-sourced movements (fetch / search / summon-from-deck) ride the uList — a verbatim,
        // separate receive slot the node forwards unchanged (bullet-3 audit F1). The node makes no
        // reveal decision; cardId presence is the sender's call. Coexists with the synthesized
        // knownList in the same frame (capture line 75).
        var uList = KnownListBuilder.RelayUList(entries.GetValueOrDefault(WireKeys.UList));

        var body = new PlayActionsBroadcastBody(
            PlayIdx: playIdx,
            Type: type,
            KnownList: played is null ? null : new[] { played },
            OppoTargetList: oppoTargets,
            UList: uList,
            // {type,cardId} forwarded so the opponent renders the choice token; selectCard dropped
            // when open==0 (hidden draw-to-hand pick). Null for a vanilla play (no keyAction).
            KeyAction: KnownListBuilder.StripKeyActionForOpponent(keyAction));

        var frame = ctx.Env with { Body = body };
        return new[] { new DispatchRoute(ctx.Other, frame, Stock.Normal) };
    }
}