Pointbuy System

using System;
using System.Collections.Generic;

public enum AttributeType
{
    Strength,
    Agility,
    Defense,
    Vitality,
    Intellect,
    Wisdom,
    Spirit
}

public class PointBuySystem
{
    private const int MaxAttributeValue = 10;
    private const int TotalPoints = 21;
    private Dictionary<AttributeType, int> attributes = new Dictionary<AttributeType, int>()
    {
        { AttributeType.Strength, 1 },
        { AttributeType.Agility, 1 },
        { AttributeType.Defense, 1 },
        { AttributeType.Vitality, 1 },
        { AttributeType.Intellect, 1 },
        { AttributeType.Wisdom, 1 },
        { AttributeType.Spirit, 1 }
    };
    private int availablePoints = TotalPoints;

    public int GetAttributeValue(AttributeType attribute)
    {
        return attributes[attribute];
    }

    public int AvailablePoints { get { return availablePoints; } }

    public bool CanBuy(AttributeType attribute)
    {
        return availablePoints > 0 && attributes[attribute] < MaxAttributeValue;
    }

    public bool BuyAttribute(AttributeType attribute)
    {
        if (!CanBuy(attribute))
        {
            return false;
        }

        if (availablePoints >= (MaxAttributeValue - attributes[attribute]))
        {
            availablePoints -= (MaxAttributeValue - attributes[attribute]);
            attributes[attribute] = MaxAttributeValue;
        }
        else
        {
            attributes[attribute] += availablePoints;
            availablePoints = 0;
        }

        return true;
    }

    public bool SellAttribute(AttributeType attribute)
    {
        if (attributes[attribute] <= 1)
        {
            return false;
        }

        attributes[attribute]--;
        availablePoints += (MaxAttributeValue - attributes[attribute] + 1);

        return true;
    }

    public void Reset()
    {
        foreach (AttributeType attribute in Enum.GetValues(typeof(AttributeType)))
        {
            attributes[attribute] = 1;
        }
        availablePoints = TotalPoints;
    }
}