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