Memory/Memory.Logic/Game.cs

namespace Memory.Logic
{
    public class Game
    {
        public const int DECKSIZE = 10;
        public const int GRIDSIZE = 5;
        public List<Card> Cards { get; } = CreateDeck(DECKSIZE);

        private static List<Card> CreateDeck(int pairs)
        {
            List<Card> cards = [];
            for (int i = 1; i < pairs + 1; i++)
            {
                cards.Add(new(i));
                cards.Add(new(i));
            }
            Random random = new();
            return [..cards.OrderBy(card => random.Next())];
        }

        public Card? GetChoice1()
        {
            return Cards.FirstOrDefault(card => card.IsChoice1);
        }

        public Card? GetChoice2()
        {
            return Cards.FirstOrDefault(card => card.IsChoice2);
        }

        public bool IsFinished()
        {
            return Cards.All(card => card.Completed);
        }

        public void ClickCard(Card card)
        {
            Card? choice1 = GetChoice1();
            Card? choice2 = GetChoice2();
            if (!card.Completed)
            {
                if ((choice1 == null && choice2 == null) || (choice1 != null && choice2 != null))
                {
                    if (choice1 != null)
                    {
                        choice1.IsChoice1 = false;
                    }
                    if (choice2 != null)
                    {
                        choice2.IsChoice2 = false;
                    }
                    card.IsChoice1 = true;
                }
                else if (choice1 != null && choice2 == null && choice1 != card)
                {
                    card.IsChoice2 = true;
                    if (choice1.Matches(card))
                    {
                        choice1.Completed = true;
                        card.Completed = true;
                        // handle score etc
                    }
                }
            }
        }
    }
}