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feat(battle-node): per-battle master seed + node-side deck shuffle

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GetOrSeedDeckMap now seeds from a Fisher-Yates shuffle of the deck keyed by the
per-battle MasterSeed, so the reveal map and the wire selfDeck share one
shuffled order. Updated the existing build-order test to the shuffle semantics.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This commit is contained in:
gamer147
2026-06-04 18:14:14 -04:00
parent 11c98bf67b
commit 6f7fcfe28e
2 changed files with 81 additions and 8 deletions
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36
SVSim.BattleNode/Sessions/Dispatch/BattleSessionState.cs
View File

@@ -1,3 +1,4 @@
using SVSim.BattleNode.Lifecycle;
using SVSim.BattleNode.Sessions;
namespace SVSim.BattleNode.Sessions.Dispatch;
@@ -9,6 +10,34 @@ namespace SVSim.BattleNode.Sessions.Dispatch;
/// <see cref="IdxToCardId"/> map via <see cref="RecordToken"/>; a reveal-gate set is still future.</summary>
internal sealed class BattleSessionState
{
/// <summary>The one random value chosen per battle. Every per-battle RNG (shared effect seed,
/// each side's deck shuffle + idxChangeSeed) derives from it via <see cref="BattleSeeds"/>.
/// Logged at session start so a battle's randomness is reproducible (future replay).</summary>
public int MasterSeed { get; }
/// <param name="masterSeed">Test hook — production uses the random default.</param>
public BattleSessionState(int? masterSeed = null) =>
MasterSeed = masterSeed ?? Random.Shared.Next();
private readonly Dictionary<IBattleParticipant, IReadOnlyList<long>> _shuffledDecks = new();
/// <summary>This side's deck, shuffled deterministically from <see cref="MasterSeed"/>
/// (Fisher–Yates). Cached per side. Both the wire selfDeck (Matched) and the reveal map
/// (<see cref="GetOrSeedDeckMap"/>) read this, so they share one shuffled order.</summary>
public IReadOnlyList<long> GetShuffledDeck(IBattleParticipant side)
{
if (_shuffledDecks.TryGetValue(side, out var cached)) return cached;
var deck = side.Context.SelfDeckCardIds.ToArray();
var rng = new Random(BattleSeeds.DeckShuffle(MasterSeed, side.ViewerId));
for (var i = deck.Length - 1; i > 0; i--)
{
var j = rng.Next(i + 1);
(deck[i], deck[j]) = (deck[j], deck[i]);
}
_shuffledDecks[side] = deck;
return deck;
}
public BattleSessionPhase SessionPhase { get; set; } = BattleSessionPhase.AwaitingInitNetwork;
public Dictionary<IBattleParticipant, long[]> PostSwapHands { get; } = new();
@@ -17,14 +46,15 @@ internal sealed class BattleSessionState
/// from add ops via <see cref="RecordToken"/>).</summary>
public Dictionary<IBattleParticipant, Dictionary<int, long>> IdxToCardId { get; } = new();
/// <summary>The sender's idx->cardId map, seeding it from its <see cref="MatchContext"/> on first
/// use. <c>BuildPlayerDeck</c> assigns deck idx = position+1, so entry (i+1) -> cardIds[i].</summary>
/// <summary>The sender's idx->cardId map, seeding it from its <see cref="GetShuffledDeck"/> order on
/// first use. Deck idx = position+1 in the shuffled order, so entry (i+1) -> shuffledDeck[i]. The
/// wire selfDeck (Matched) is built from the same shuffled order, so the two agree.</summary>
public IReadOnlyDictionary<int, long> GetOrSeedDeckMap(IBattleParticipant side)
{
if (!IdxToCardId.TryGetValue(side, out var map))
{
map = new Dictionary<int, long>();
var deck = side.Context.SelfDeckCardIds;
var deck = GetShuffledDeck(side);
for (var i = 0; i < deck.Count; i++) map[i + 1] = deck[i];
IdxToCardId[side] = map;
}

53
SVSim.UnitTests/BattleNode/Sessions/BattleSessionStateTests.cs
View File

@@ -27,17 +27,21 @@ public class BattleSessionStateTests
FieldId: 0, IsOfficial: 0, BattleType: 11);
[Test]
public void GetOrSeedDeckMap_maps_idx_1based_to_deck_cardIds()
public void GetOrSeedDeckMap_maps_idx_1based_to_the_shuffled_order()
{
var state = new BattleSessionState();
// The map seeds from GetShuffledDeck, not raw build order. idx (i+1) -> shuffledDeck[i],
// and the set of cardIds is unchanged (1..3 present, 4 absent).
var state = new BattleSessionState(masterSeed: 12345);
var p = new StubParticipant(1, Ctx(900L, 901L, 902L));
var shuffled = state.GetShuffledDeck(p);
var map = state.GetOrSeedDeckMap(p);
Assert.That(map[1], Is.EqualTo(900L));
Assert.That(map[2], Is.EqualTo(901L));
Assert.That(map[3], Is.EqualTo(902L));
Assert.That(map[1], Is.EqualTo(shuffled[0]));
Assert.That(map[2], Is.EqualTo(shuffled[1]));
Assert.That(map[3], Is.EqualTo(shuffled[2]));
Assert.That(map.ContainsKey(4), Is.False);
Assert.That(new[] { map[1], map[2], map[3] }, Is.EquivalentTo(new[] { 900L, 901L, 902L }));
}
[Test]
@@ -47,4 +51,43 @@ public class BattleSessionStateTests
var p = new StubParticipant(1, Ctx(900L));
Assert.That(state.GetOrSeedDeckMap(p), Is.SameAs(state.GetOrSeedDeckMap(p)));
}
[Test]
public void GetShuffledDeck_is_a_permutation_of_the_input()
{
var state = new BattleSessionState(masterSeed: 12345);
var p = new StubParticipant(1001, Ctx(DistinctDeck()));
Assert.That(state.GetShuffledDeck(p), Is.EquivalentTo(DistinctDeck()),
"same multiset of cards, just reordered");
}
[Test]
public void GetShuffledDeck_actually_reorders_a_distinct_deck()
{
var state = new BattleSessionState(masterSeed: 12345);
var p = new StubParticipant(1001, Ctx(DistinctDeck()));
Assert.That(state.GetShuffledDeck(p), Is.Not.EqualTo(DistinctDeck()),
"a 30-card distinct deck should not survive the shuffle in original order");
}
[Test]
public void GetShuffledDeck_is_deterministic_for_same_master_seed_and_viewer()
{
var a = new BattleSessionState(masterSeed: 777).GetShuffledDeck(new StubParticipant(1001, Ctx(DistinctDeck())));
var b = new BattleSessionState(masterSeed: 777).GetShuffledDeck(new StubParticipant(1001, Ctx(DistinctDeck())));
Assert.That(a, Is.EqualTo(b));
}
[Test]
public void GetShuffledDeck_differs_across_master_seeds()
{
var a = new BattleSessionState(masterSeed: 1).GetShuffledDeck(new StubParticipant(1001, Ctx(DistinctDeck())));
var b = new BattleSessionState(masterSeed: 2).GetShuffledDeck(new StubParticipant(1001, Ctx(DistinctDeck())));
Assert.That(a, Is.Not.EqualTo(b));
}
private static long[] DistinctDeck() =>
Enumerable.Range(1, 30).Select(i => 200_000_000L + i).ToArray();
}