﻿// The MIT License
// 
// Copyright (c) 2012-2015 Jordan E. Terrell
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

using System;
using System.Collections.Generic;

namespace iSynaptic.Commons.Reflection
{
    public class TypeHierarchyComparer : IComparer<Type>
    {
        public int Compare(Type left, Type right)
        {
            if (left == null && right == null)
                return 0;

            if (left == null)
                return -1;

            if (right == null)
                return 1;

            if (left.IsInterface && !right.IsInterface)
                return -1;

            if (!left.IsInterface && right.IsInterface)
                return 1;

            int result = 0;

            if (left.IsAssignableFrom(right))
                result--;

            if (right.IsAssignableFrom(left))
                result++;

            return result;
        }
    }
}
