src/solitaire/Depot.java

   1 package solitaire;
   2
   3 import java.util.LinkedList;
   4 import java.util.List;
   5 import java.util.Optional;
   6 import java.util.stream.Collectors;
   7
   8 final class Depot {
   9     private final List<Card> cards;
  10
  11     Depot(List<Card> cards) {
  12         if (cards.isEmpty())
  13             throw new IllegalArgumentException("Depot should be initialized with at least one card");
  14
  15         this.cards = new LinkedList<>(cards);
  16         this.cards.getLast().reveal();
  17     }
  18
  19     private static boolean isValidNextCard(Card lastCard, Card nextCard) {
  20         if (nextCard.getSuit().isRed() == lastCard.getSuit().isRed())
  21             return false;
  22
  23         return lastCard.getRank().isSuccessorOf(nextCard.getRank());
  24     }
  25
  26     private boolean isValidPlacement(Card card) {
  27         if (cards.isEmpty())
  28             return card.getRank() == Rank.KING;
  29
  30         return isValidNextCard(cards.getLast(), card);
  31     }
  32
  33     private static boolean isValidRun(List<Card> run) {
  34         Card prev = null;
  35
  36         for (Card next : run) {
  37             if (next.isHidden() || (prev != null && !isValidNextCard(prev, next)))
  38                 return false;
  39
  40             prev = next;
  41         }
  42
  43         return true;
  44     }
  45
  46     boolean add(List<Card> run) {
  47         /*
  48          * no invalid run can be generated by the game, so we only need to check
  49          * placement.
  50          */
  51         if (!isValidPlacement(run.getFirst()))
  52             return false;
  53
  54         cards.addAll(run);
  55         return true;
  56     }
  57
  58     boolean add(Card card) {
  59         return add(List.of(card));
  60     }
  61
  62     Optional<List<Card>> remove(int size) {
  63         if (size < 1)
  64             throw new IllegalArgumentException("Size must be a positive integer");
  65
  66         if (cards.size() < size)
  67             return Optional.empty();
  68
  69         List<Card> slice = cards.subList(cards.size() - size, cards.size());
  70
  71         if (!isValidRun(slice))
  72             return Optional.empty();
  73
  74         List<Card> run = List.copyOf(slice);
  75         slice.clear();
  76
  77         if (!cards.isEmpty())
  78             cards.getLast().reveal();
  79
  80         return Optional.of(run);
  81     }
  82
  83     @Override
  84     public String toString() {
  85         if (cards.isEmpty())
  86             return "<   >";
  87
  88         return cards.stream().map(String::valueOf).collect(Collectors.joining("\n"));
  89     }
  90 }