Add deal() method to the Decks

1 files changed, 30 insertions, 3 deletions

diff --git a/src/main/java/org/luxons/sevenwonders/game/Decks.java b/src/main/java/org/luxons/sevenwonders/game/Decks.java
index 72dff4e9..be811b6f 100644
--- a/src/main/java/org/luxons/sevenwonders/game/Decks.java
+++ b/src/main/java/org/luxons/sevenwonders/game/Decks.java
@@ -1,6 +1,6 @@
 package org.luxons.sevenwonders.game;
 
-import java.util.Collections;
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -9,13 +9,40 @@ import org.luxons.sevenwonders.game.cards.Card;
 
 public class Decks {
 
+    private static final int HAND_SIZE = 7;
+
     private Map<Integer, List<Card>> cardsPerAge = new HashMap<>();
 
     public Decks(Map<Integer, List<Card>> cardsPerAge) {
         this.cardsPerAge = cardsPerAge;
     }
 
-    public List<Card> getCards(int age) {
-        return cardsPerAge.getOrDefault(age, Collections.emptyList());
+    Map<Integer, List<Card>> deal(int age, int nbPlayers) {
+        List<Card> deck = getDeck(age);
+        validateNbCards(deck, nbPlayers);
+        return deal(deck, nbPlayers);
+    }
+
+    private List<Card> getDeck(int age) {
+        List<Card> deck = cardsPerAge.get(age);
+        if (deck == null) {
+            throw new IllegalArgumentException("No deck found for age " + age);
+        }
+        return deck;
+    }
+
+    private void validateNbCards(List<Card> deck, int nbPlayers) {
+        if (nbPlayers * HAND_SIZE != deck.size()) {
+            throw new IllegalArgumentException(
+                    String.format("%d cards is not the expected number for %d players", deck.size(), nbPlayers));
+        }
+    }
+
+    private Map<Integer, List<Card>> deal(List<Card> deck, int nbPlayers) {
+        Map<Integer, List<Card>> hands = new HashMap<>(nbPlayers);
+        for (int i = 0; i < deck.size(); i++) {
+            hands.putIfAbsent(i % nbPlayers, new ArrayList<>()).add(deck.get(i));
+        }
+        return hands;
     }
 }