diff --git a/SVSim.BattleNode/Sessions/Dispatch/KnownListBuilder.cs b/SVSim.BattleNode/Sessions/Dispatch/KnownListBuilder.cs
index 9ec92c0..2df5637 100644
--- a/SVSim.BattleNode/Sessions/Dispatch/KnownListBuilder.cs
+++ b/SVSim.BattleNode/Sessions/Dispatch/KnownListBuilder.cs
@@ -42,6 +42,41 @@ internal static class KnownListBuilder
return null;
}
+ /// Count hidden, non-reproduced shared-RNG draws implied by an orderList: move ops
+ /// from Deck(0) to Hand(10) for a non-played, unrevealed card (a random fetch the opponent can't
+ /// reproduce — it can't enumerate the active player's deck). Each such moved card = one crank the
+ /// receiver must apply (spin += 1). Skips: the played card's own move (idx == playIdx);
+ /// any idx in (its identity is already on the wire — a revealed uList
+ /// fetch); and lot-based randoms (a move op carrying a rand array — the receiver
+ /// reproduces those by re-rolling, so counting would double-crank). An ordinary card DRAW also
+ /// surfaces as a hidden move(0→10) but is a deterministic top-of-deck pop (no shared-stream
+ /// roll) and must NOT be counted — distinguishing it from a random fetch on the wire is the open
+ /// capture (real-spin design §3.1; the spec's Task 0). Base 0; see the real-spin design doc.
+ public static int CountHiddenDraws(object? orderList, int playIdx, IReadOnlySet revealed)
+ {
+ if (orderList is not IEnumerable ops) return 0;
+ var count = 0;
+ foreach (var op in ops)
+ {
+ if (op is not IDictionary opDict) continue;
+ if (!opDict.TryGetValue("move", out var moveRaw) || moveRaw is not IDictionary move) continue;
+
+ if (move.ContainsKey("rand")) continue; // lot random → receiver re-rolls
+ if (!move.TryGetValue("from", out var fromRaw) || (int)AsLong(fromRaw) != 0) continue; // not from Deck
+ if (!move.TryGetValue("to", out var toRaw) || (int)AsLong(toRaw) != 10) continue; // not to Hand
+ if (!move.TryGetValue("idx", out var idxRaw) || idxRaw is not IEnumerable idxList) continue;
+
+ foreach (var i in idxList)
+ {
+ var idx = (int)AsLong(i);
+ if (idx == playIdx) continue; // the played card's own move
+ if (revealed.Contains(idx)) continue; // opponent already knows this card's identity
+ count++;
+ }
+ }
+ return count;
+ }
+
/// Mine generated-token identities from a sender's add ops: yields
/// (idx, cardId, isSelf) for every idx in each {add:{idx:[...], isSelf, card:{cardId}}}
/// op. isSelf is surfaced verbatim (the sender's perspective tag on CardObj.IsPlayer,
diff --git a/SVSim.UnitTests/BattleNode/Sessions/KnownListBuilderTests.cs b/SVSim.UnitTests/BattleNode/Sessions/KnownListBuilderTests.cs
index 3133844..a7381a0 100644
--- a/SVSim.UnitTests/BattleNode/Sessions/KnownListBuilderTests.cs
+++ b/SVSim.UnitTests/BattleNode/Sessions/KnownListBuilderTests.cs
@@ -20,6 +20,78 @@ public class KnownListBuilderTests
}
};
+ // A move op dict allowing extra keys (e.g. "rand") for CountHiddenDraws fixtures.
+ private static Dictionary MoveOp(long[] idxs, int from, int to,
+ IDictionary? extra = null)
+ {
+ var move = new Dictionary
+ {
+ ["idx"] = idxs.Select(i => (object?)i).ToList(),
+ ["isSelf"] = 1L, ["from"] = (long)from, ["to"] = (long)to,
+ };
+ if (extra is not null) foreach (var kv in extra) move[kv.Key] = kv.Value;
+ return new Dictionary { ["move"] = move };
+ }
+
+ private static readonly IReadOnlySet NoneRevealed = new HashSet();
+
+ [Test]
+ public void CountHiddenDraws_counts_a_hidden_deck_to_hand_fetch()
+ {
+ // Hoverboard-shaped: move(0->10) for a non-played, unrevealed token idx.
+ var orderList = new List { MoveOp(new[] { 31L }, from: 0, to: 10) };
+ Assert.That(KnownListBuilder.CountHiddenDraws(orderList, playIdx: 3, NoneRevealed), Is.EqualTo(1));
+ }
+
+ [Test]
+ public void CountHiddenDraws_ignores_the_played_cards_own_move()
+ {
+ // The played card moving hand(10)->field(20) is not a draw.
+ var orderList = new List { MoveOp(new[] { 3L }, from: 10, to: 20) };
+ Assert.That(KnownListBuilder.CountHiddenDraws(orderList, playIdx: 3, NoneRevealed), Is.EqualTo(0));
+ }
+
+ [Test]
+ public void CountHiddenDraws_ignores_a_visible_destroy()
+ {
+ // A visible field(20)->cemetery(30) destroy is reproduced by the receiver → 0.
+ var orderList = new List { MoveOp(new[] { 8L }, from: 20, to: 30) };
+ Assert.That(KnownListBuilder.CountHiddenDraws(orderList, playIdx: 3, NoneRevealed), Is.EqualTo(0));
+ }
+
+ [Test]
+ public void CountHiddenDraws_ignores_a_revealed_fetch()
+ {
+ // The fetched idx's identity was revealed to the opponent (in `revealed`) → 0.
+ var orderList = new List { MoveOp(new[] { 31L }, from: 0, to: 10) };
+ var revealed = new HashSet { 31 };
+ Assert.That(KnownListBuilder.CountHiddenDraws(orderList, playIdx: 3, revealed), Is.EqualTo(0));
+ }
+
+ [Test]
+ public void CountHiddenDraws_ignores_a_lot_based_random()
+ {
+ // A move op carrying a `rand` array is reproduced (re-rolled) by the receiver → 0.
+ var rand = new Dictionary { ["rand"] = new List { 0.5d } };
+ var orderList = new List { MoveOp(new[] { 31L }, from: 0, to: 10, extra: rand) };
+ Assert.That(KnownListBuilder.CountHiddenDraws(orderList, playIdx: 3, NoneRevealed), Is.EqualTo(0));
+ }
+
+ [Test]
+ public void CountHiddenDraws_counts_each_hidden_card_in_a_multi_fetch()
+ {
+ var orderList = new List { MoveOp(new[] { 31L, 32L }, from: 0, to: 10) };
+ Assert.That(KnownListBuilder.CountHiddenDraws(orderList, playIdx: 3, NoneRevealed), Is.EqualTo(2));
+ }
+
+ [Test]
+ public void CountHiddenDraws_returns_zero_for_a_vanilla_play()
+ {
+ var orderList = new List { MoveOp(new[] { 3L }, from: 10, to: 20) };
+ Assert.That(KnownListBuilder.CountHiddenDraws(orderList, playIdx: 3, NoneRevealed), Is.EqualTo(0));
+ Assert.That(KnownListBuilder.CountHiddenDraws(null, playIdx: 3, NoneRevealed), Is.EqualTo(0));
+ }
+
[Test]
public void ExtractMoveTo_returns_to_for_matching_idx()
{