using System;

namespace Gwen
{
    /// <summary>
    /// Represents outer spacing.
    /// </summary>
    public struct Margin : IEquatable<Margin>
    {
        public int Top;
        public int Bottom;
        public int Left;
        public int Right;

        // common values
        public static Margin Zero = new Margin(0, 0, 0, 0);
        public static Margin One = new Margin(1, 1, 1, 1);
        public static Margin Two = new Margin(2, 2, 2, 2);
        public static Margin Three = new Margin(3, 3, 3, 3);
        public static Margin Four = new Margin(4, 4, 4, 4);
        public static Margin Five = new Margin(5, 5, 5, 5);
        public static Margin Six = new Margin(6, 6, 6, 6);
        public static Margin Seven = new Margin(7, 7, 7, 7);
        public static Margin Eight = new Margin(8, 8, 8, 8);
        public static Margin Nine = new Margin(9, 9, 9, 9);
        public static Margin Ten = new Margin(10, 10, 10, 10);

        public Margin(int left, int top, int right, int bottom)
        {
            Top = top;
            Bottom = bottom;
            Left = left;
            Right = right;
        }

        public bool Equals(Margin other)
        {
            return other.Top == Top && other.Bottom == Bottom && other.Left == Left && other.Right == Right;
        }

        public static bool operator==(Margin lhs, Margin rhs)
        {
            return lhs.Equals(rhs);
        }

        public static bool operator!=(Margin lhs, Margin rhs)
        {
            return !lhs.Equals(rhs);
        }

        public override bool Equals(object obj)
        {
            if (ReferenceEquals(null, obj)) return false;
            if (obj.GetType() != typeof (Margin)) return false;
            return Equals((Margin) obj);
        }

        public override int GetHashCode()
        {
            unchecked
            {
                int result = Top;
                result = (result*397) ^ Bottom;
                result = (result*397) ^ Left;
                result = (result*397) ^ Right;
                return result;
            }
        }
    }
}