Improve card-based Commander deck generation legality and weighting

forge-gui/src/main/java/forge/deck/DeckgenUtil.java

@@ -684,8 +684,7 @@ public static Deck generateRandomCommanderDeck(PaperCard commander, DeckFormat f
             }else {
                 String matrixKey = (format.equals(DeckFormat.TinyLeaders) ? DeckFormat.Commander : format).toString(); //use Commander for Tiny Leaders
                 List<Map.Entry<PaperCard, Integer>> potentialCards = new ArrayList<>(CardRelationMatrixGenerator.cardPools.get(matrixKey).get(commander.getName()));
-                Collections.shuffle(potentialCards, MyRandom.getRandom());
-                for(Map.Entry<PaperCard,Integer> pair:potentialCards){
+                for(Map.Entry<PaperCard,Integer> pair:getWeightedRandomizedCardPool(potentialCards)){
                     if(format.isLegalCard(pair.getKey())) {
                         preSelectedCards.add(pair.getKey());
                     }
@@ -819,6 +818,20 @@ else if (commander.getRules().canBePartnerCommander()) {
         return deck;
     }
 
+    private static List<Map.Entry<PaperCard, Integer>> getWeightedRandomizedCardPool(final List<Map.Entry<PaperCard, Integer>> potentialCards) {
+        final Map<Map.Entry<PaperCard, Integer>, Double> sortKeys = new IdentityHashMap<>();
+        for (final Map.Entry<PaperCard, Integer> cardEntry : potentialCards) {
+            sortKeys.put(cardEntry, getWeightedRandomSortKey(cardEntry));
+        }
+        potentialCards.sort(Comparator.comparingDouble(sortKeys::get).reversed());
+        return potentialCards;
+    }
+
+    private static double getWeightedRandomSortKey(final Map.Entry<PaperCard, Integer> cardEntry) {
+        final int weight = Math.max(1, cardEntry.getValue());
+        return Math.log(MyRandom.getRandom().nextDouble()) / weight;
+    }
+
     public static Map<ManaCostShard, Integer> suggestBasicLandCount(Deck d) {
         int W=0, U=0, R=0, B=0, G=0, total=0;
         List<PaperCard> cards = d.getOrCreate(DeckSection.Main).toFlatList();

forge-gui/src/main/java/forge/gamemodes/limited/CardThemedCommanderDeckBuilder.java

@@ -1,6 +1,9 @@
 package forge.gamemodes.limited;
 
+import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.stream.Collectors;
 
 import com.google.common.collect.Lists;
@@ -20,7 +23,7 @@ public class CardThemedCommanderDeckBuilder extends CardThemedDeckBuilder {
 
     public CardThemedCommanderDeckBuilder(PaperCard commanderCard0, PaperCard partner0, final List<PaperCard> dList, boolean isForAI, DeckFormat format) {
         super(new DeckGenPool(FModel.getMagicDb().getCommonCards().getUniqueCards()), format);
-        this.availableList = dList;
+        this.availableList = new ArrayList<>(dList);
         keyCard = commanderCard0;
         secondKeyCard = partner0;
         // remove Unplayables
@@ -32,6 +35,8 @@ public CardThemedCommanderDeckBuilder(PaperCard commanderCard0, PaperCard partne
             this.aiPlayables = Lists.newArrayList(availableList);
         }
         this.availableList.removeAll(aiPlayables);
+        this.aiPlayables = uniqueCardNamesForSingletonDeck(aiPlayables);
+        this.availableList = uniqueCardNamesForSingletonDeck(availableList);
         targetSize=format.getMainRange().getMinimum();
         colors = keyCard.getRules().getColorIdentity();
         colors = ColorSet.combine(colors, keyCard.getRules().getColorIdentity());
@@ -59,6 +64,13 @@ protected void addLandKeyCards(){
         //do nothing as keycards are commander/partner and are added by the DeckGenUtils
     }
 
+    @Override
+    protected void extendPlaysets(int numSpellsNeeded) {
+        // Commander-family formats are singleton except for basic lands and cards
+        // with explicit deckbuilding exceptions. Do not fill gaps by duplicating
+        // cards already selected for the main deck.
+    }
+
     @Override
     protected void addThirdColorCards(int num) {
         //do nothing as we cannot add extra colours beyond commanders
@@ -78,4 +90,25 @@ protected String generateName() {
         return keyCard.getName() +" based commander deck";
     }
 
+    private List<PaperCard> uniqueCardNamesForSingletonDeck(final List<PaperCard> cards) {
+        final List<PaperCard> result = new ArrayList<>();
+        final Map<String, Integer> countsByName = new HashMap<>();
+        countsByName.put(keyCard.getName(), 1);
+        if (secondKeyCard != null) {
+            countsByName.put(secondKeyCard.getName(), 1);
+        }
+
+        for (final PaperCard card : cards) {
+            final int maxCopies = format.getMaxCardCopies(card);
+            final String name = card.getName();
+            final int currentCount = countsByName.getOrDefault(name, 0);
+            if (currentCount < maxCopies) {
+                result.add(card);
+                countsByName.put(name, currentCount + 1);
+            }
+        }
+
+        return result;
+    }
+
 }

forge-gui/src/main/java/forge/gamemodes/limited/CardThemedDeckBuilder.java

@@ -604,7 +604,7 @@ public boolean test(PaperCard card) {
                         && !card.getRules().getMainPart().getType().isLand();
             }
         };
-        List<PaperCard> possibleList = Lists.newArrayList(pool.getAllCards(possibleFromFullPool));
+        List<PaperCard> possibleList = limitCopiesForFormat(Lists.newArrayList(pool.getAllCards(possibleFromFullPool)));
         //ensure we do not add more keycards in case they are commanders
         if (keyCard != null) {
             possibleList.removeAll(StaticData.instance().getCommonCards().getAllCards(keyCard));
@@ -830,7 +830,7 @@ private void addRandomCards(int num) {
                 && !card.getRules().getAiHints().getRemRandomDecks()
                 && !card.getRules().getMainPart().getType().isLand();
 
-        List<PaperCard> possibleList = Lists.newArrayList(pool.getAllCards(possibleFromFullPool));
+        List<PaperCard> possibleList = limitCopiesForFormat(Lists.newArrayList(pool.getAllCards(possibleFromFullPool)));
         //ensure we do not add more keycards in case they are commanders
         if (keyCard != null) {
             possibleList.removeAll(StaticData.instance().getCommonCards().getAllCards(keyCard));
@@ -844,6 +844,24 @@ private void addRandomCards(int num) {
         addManaCurveCards(possibleList, num, "Random Card");
     }
 
+    protected List<PaperCard> limitCopiesForFormat(final List<PaperCard> cards) {
+        final Map<String, Integer> countsByName = new HashMap<>();
+        for (final PaperCard card : deckList) {
+            countsByName.merge(card.getName(), 1, Integer::sum);
+        }
+
+        final List<PaperCard> result = new ArrayList<>();
+        for (final PaperCard card : cards) {
+            final String name = card.getName();
+            final int currentCount = countsByName.getOrDefault(name, 0);
+            if (currentCount < format.getMaxCardCopies(card)) {
+                result.add(card);
+                countsByName.put(name, currentCount + 1);
+            }
+        }
+        return result;
+    }
+
     /**
      * Add creatures to the deck.
      *