namespace su.divan2000.PLandDS_hanoi
{
    class HanoiTowers
    {
        private int[] tower_A;
        private int[] tower_B;
        private int[] tower_C;

        private int size;

        public HanoiTowers(int size)
        {
            this.size = size;
            tower_A = new int[size];
            tower_B = new int[size];
            tower_C = new int[size];

            for (int i = 0; i < size; i++)
            {
                tower_A[i] = size - i;
            }
        }

        public string toString()
        {
            int charsPerTower = size.ToString().Length;
            string result = "";
            for (int i = size - 1; i >= 0; i--)
            {
                result += tower_A[i].ToString().PadLeft(charsPerTower).Replace("0", "|") + " ";
                result += tower_B[i].ToString().PadLeft(charsPerTower).Replace("0", "|") + " ";
                result += tower_C[i].ToString().PadLeft(charsPerTower).Replace("0", "|") + "\n";
            }
            return result;
        }

        public void move(int from, int to)
        {
            int[] sourceTower = getTower(from);
            int[] targetTower = getTower(to);

            int sourceTopIndex = getTopIndex(sourceTower);
            int targetTopIndex = getTopIndex(targetTower);

            if (sourceTopIndex == -1)
            {
                throw new InvalidOperationException("No disk to move");
            }

            if (targetTopIndex != -1 && sourceTower[sourceTopIndex] > targetTower[targetTopIndex])
            {
                throw new InvalidOperationException("Cannot place larger disk on smaller one");
            }

            targetTower[targetTopIndex + 1] = sourceTower[sourceTopIndex];
            sourceTower[sourceTopIndex] = 0;
        }

        private int[] getTower(int index)
        {
            switch (index)
            {
                case 0: return tower_A;
                case 1: return tower_B;
                case 2: return tower_C;
                default: throw new ArgumentException("Invalid tower index");
            }
        }

        private int getTopIndex(int[] tower)
        {
            for (int i = size - 1; i >= 0; i--)
            {
                if (tower[i] != 0)
                {
                    return i;
                }
            }
            return -1; // Tower is full
        }
    }
}