Add initial new themed chaos draft functionality

Add new randomizer

forge-core/src/main/java/forge/card/CardEdition.java

@@ -124,6 +124,7 @@ public final class CardEdition implements Comparable<CardEdition> { // immutable
     private boolean smallSetOverride = false;
     private String boosterMustContain = "";
     private String boosterReplaceSlotFromPrintSheet = "";
+    private String[] chaosDraftThemes = new String[0];
     private boolean doublePickToStartRound = false;
     private final CardInSet[] cards;
     private final Map<String, Integer> tokenNormalized;
@@ -195,6 +196,7 @@ public final class CardEdition implements Comparable<CardEdition> { // immutable
     public boolean getDoublePickToStartRound() { return doublePickToStartRound; }
     public String getBoosterMustContain() { return boosterMustContain; }
     public String getBoosterReplaceSlotFromPrintSheet() { return boosterReplaceSlotFromPrintSheet; }
+    public String[] getChaosDraftThemes() { return chaosDraftThemes; }
     public CardInSet[] getCards() { return cards; }
     public boolean isModern() { return getDate().after(parseDate("2003-07-27")); } //8ED and above are modern except some promo cards and others
 
@@ -385,6 +387,9 @@ public final class CardEdition implements Comparable<CardEdition> { // immutable
 
             res.boosterMustContain = section.get("BoosterMustContain", ""); // e.g. Dominaria guaranteed legendary creature
             res.boosterReplaceSlotFromPrintSheet = section.get("BoosterReplaceSlotFromPrintSheet", ""); // e.g. Zendikar Rising guaranteed double-faced card
+
+            res.chaosDraftThemes = section.get("ChaosDraftThemes", "").split(";"); // semicolon separated list of theme names
+
             return res;
         }
 

forge-core/src/main/java/forge/item/generation/ChaosBoosterSupplier.java

@@ -1,25 +1,26 @@
 package forge.item.generation;
 
+import com.google.common.collect.Iterables;
 import forge.card.CardEdition;
 import forge.item.BoosterPack;
 import forge.item.PaperCard;
+import forge.util.BagRandomizer;
 
 import java.util.List;
 
 public class ChaosBoosterSupplier implements IUnOpenedProduct {
-    private List<CardEdition> sets;
+    private BagRandomizer<CardEdition> randomizer;
 
-    public ChaosBoosterSupplier(List<CardEdition> sets) {
-        this.sets = sets;
+    public ChaosBoosterSupplier(Iterable<CardEdition> sets) throws Exception {
+        if (Iterables.size(sets) <= 0) {
+            throw new Exception("At least one set needed to generate chaos draft!");
+        }
+        randomizer = new BagRandomizer<>(sets);
     }
 
     @Override
     public List<PaperCard> get() {
-        if (sets.size() == 0) {
-            System.out.println("No chaos boosters left to supply.");
-            return null;
-        }
-        final CardEdition set = sets.remove(0);
+        final CardEdition set = randomizer.getNextItem();
         final BoosterPack pack = new BoosterPack(set.getCode(), set.getBoosterTemplate());
         return pack.getCards();
     }

forge-core/src/main/java/forge/util/BagRandomizer.java

@@ -0,0 +1,68 @@
+package forge.util;
+
+import java.security.SecureRandom;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.Random;
+
+/**
+ * Data structure that allows random draws from a set number of items,
+ * where all items are returned once before the first will be retrieved.
+ * The bag will be shuffled after each time all items have been returned.
+ * @param <T> an object
+ */
+public class BagRandomizer<T > implements Iterable<T>{
+    private static Random random = new SecureRandom();
+
+    private T[] bag;
+    private int currentPosition = 0;
+
+    public BagRandomizer(T[] items) {
+        bag = items;
+    }
+
+    public BagRandomizer(Iterable<T> items) {
+        ArrayList<T> list = new ArrayList<>();
+        for (T item : items) {
+            list.add(item);
+        }
+        bag = (T[]) list.toArray();
+    }
+
+    public T getNextItem() {
+        // reset bag if last position is reached
+        if (currentPosition >= bag.length) {
+            shuffleBag();
+            currentPosition = 0;
+        }
+        return bag[currentPosition++];
+    }
+
+    private void shuffleBag() {
+        int n = bag.length;
+        for (int i = 0; i < n; i++) {
+            int r = (int) (random.nextDouble() * (i + 1));
+            T swap = bag[r];
+            bag[r] = bag[i];
+            bag[i] = swap;
+        }
+    }
+
+    @Override
+    public Iterator<T> iterator() {
+        return new BagRandomizerIterator<T>();
+    }
+
+    private class BagRandomizerIterator<T> implements Iterator<T> {
+
+        @Override
+        public boolean hasNext() {
+            return bag.length > 0;
+        }
+
+        @Override
+        public T next() {
+            return (T) BagRandomizer.this.getNextItem();
+        }
+    }
+}