Add support for up to 6 players.

internal/ai/predict.go

@@ -19,27 +19,35 @@ type ctx struct {
 }
 
 func newCtx(v *game.View, m *Memory) *ctx {
-	cx := &ctx{v: v, m: m, me: &v.Players[v.YouSeat], oppSeat: m.Opp.Seat, pools: map[int][]game.Card{}}
+	cx := &ctx{v: v, m: m, me: v.PlayerView(v.YouSeat), oppSeat: v.YourOpponent, pools: map[int][]game.Card{}}
+	// The round's pairing says exactly who the bot is preparing for, so it
+	// plans against that one rival even at a six-player table. Falling back to
+	// any other seat keeps a malformed view from wedging the bot.
 	if cx.oppSeat == cx.me.Seat || cx.oppSeat < 0 {
-		// Memory hasn't observed yet (shouldn't happen in practice).
 		for _, p := range v.Players {
 			if p.Seat != v.YouSeat {
 				cx.oppSeat = p.Seat
+				break
 			}
 		}
 	}
 	return cx
 }
 
+// opp is the model of the opponent this round's battle is against.
+func (cx *ctx) opp() *OppModel { return cx.m.Opp(cx.oppSeat) }
+
 func (cx *ctx) nextSimID() string {
 	cx.simID++
 	return fmt.Sprintf("sim-%d", cx.simID)
 }
 
 // unseenPool lists the printed cards of a tier that the bot cannot account
-// for anywhere it can see — its own deck, the opponent model, the shop row.
+// for anywhere it can see — its own deck, every opponent model, the shop row.
 // Hidden opponent cards are drawn from this pool, so the bot's guesses
-// respect card counting without peeking at the real decks.
+// respect card counting without peeking at the real decks. It counts against
+// the whole table's known cards, and against the combined contents of every
+// pack in play, which is what a human counting cards would be working from.
 func (cx *ctx) unseenPool(tier int) []game.Card {
 	if pool, ok := cx.pools[tier]; ok {
 		return pool
@@ -53,14 +61,16 @@ func (cx *ctx) unseenPool(tier int) []game.Card {
 	for _, c := range cx.me.Deck {
 		note(c)
 	}
-	for _, c := range cx.m.Opp.Known {
-		note(c)
+	for _, opp := range cx.m.Opps {
+		for _, c := range opp.Known {
+			note(c)
+		}
 	}
 	for _, c := range cx.v.ShopRow {
 		note(c)
 	}
 	var pool []game.Card
-	for _, c := range game.TierContentsForPack(cx.v.Pack, tier) {
+	for _, c := range game.TierContentsForPacks(cx.v.Packs, tier) {
 		if seen[c.Name] > 0 {
 			seen[c.Name]--
 			continue
@@ -75,10 +85,11 @@ func (cx *ctx) unseenPool(tier int) []game.Card {
 // known cards as-is, hidden cards drawn from the unseen pool of their tier
 // (or their named template, when a pick was later revealed).
 func (cx *ctx) sampleOppDeck() []game.Card {
-	deck := append([]game.Card(nil), cx.m.Opp.Known...)
-	for _, h := range cx.m.Opp.Hidden {
+	opp := cx.opp()
+	deck := append([]game.Card(nil), opp.Known...)
+	for _, h := range opp.Hidden {
 		var c game.Card
-		if t, ok := templateByName(cx.v.Pack, h.Name); ok {
+		if t, ok := templateByName(cx.v.Packs, h.Name); ok {
 			c = t
 		} else if pool := cx.unseenPool(h.Tier); len(pool) > 0 {
 			c = pool[rand.IntN(len(pool))]