using System;

namespace Chernobyl.Calculator
{
    /// <summary>
    /// A version of an ICalculator that can perform 
    /// calculations on ints.
    /// </summary>
    public struct UIntCalculator : ICalculator<uint>
    {
        /// <summary>
        /// Adds one uint to another.
        /// </summary>
        /// <param name="left">The left side of the addition operation.</param>
        /// <param name="right">The right side of the addition operation.</param>
        /// <returns>The result of the addition.</returns>
        public uint Add(uint left, uint right)
        {
            return left + right;
        }

        /// <summary>
        /// Subtracts one uint from another.
        /// </summary>
        /// <param name="left">The left side of the subtraction operation.</param>
        /// <param name="right">The right side of the subtraction operation.</param>
        /// <returns>The result of the subtraction.</returns>
        public uint Subtract(uint left, uint right)
        {
            return left - right;
        }

        /// <summary>
        /// Divides two uints.
        /// </summary>
        /// <param name="dividend">The dividend.</param>
        /// <param name="divisor">The divisor.</param>
        /// <returns>The result of the divide.</returns>
        public uint Divide(uint dividend, uint divisor)
        {
            return dividend / divisor;
        }

        /// <summary>
        /// Multiplies two uints together.
        /// </summary>
        /// <param name="left">The left side of the multiplication operation.</param>
        /// <param name="right">The right side of the multiplication operation.</param>
        /// <returns>The result of the multiplication.</returns>
        public uint Multiply(uint left, uint right)
        {
            return left * right;
        }

        /// <summary>
        /// Negates a uint.
        /// </summary>
        /// <param name="item">The uint to negate.</param>
        /// <returns>The result of the negation.</returns>
        public uint Negate(uint item)
        {
            // uint can't go below 0
            throw new Exception("Negate called on a UIntCalculator; uints cannot be negated because they are unsigned types.");
        }

        /// <summary>
        /// Compares two uints.
        /// </summary>
        /// <param name="left">The left side of the comparison operation.</param>
        /// <param name="right">The right side of the comparison operation.</param>
        /// <returns>True if the two are the same, false if otherwise.</returns>
        public bool Compare(uint left, uint right)
        {
            return (left == right);
        }
    }
}