// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System.Linq;
using System.Reflection;

namespace System.Net.Http
{
    internal static class TypeExtensions
    {
#if NETFX_CORE
        private static bool EqualTo(this Type[] t1, Type[] t2)
        {
            if (t1.Length != t2.Length)
            {
                return false;
            }

            for (int idx = 0; idx < t1.Length; ++idx)
            {
                if (t1[idx] != t2[idx])
                {
                    return false;
                }
            }

            return true;
        }

        public static ConstructorInfo GetConstructor(this Type type, Type[] types)
        {
            return type.GetTypeInfo().DeclaredConstructors
                                     .Where(c => c.IsPublic)
                                     .SingleOrDefault(c => c.GetParameters()
                                                            .Select(p => p.ParameterType).ToArray().EqualTo(types));
        }
#endif

        public static Type ExtractGenericInterface(this Type queryType, Type interfaceType)
        {
            Func<Type, bool> matchesInterface = t => t.IsGenericType() && t.GetGenericTypeDefinition() == interfaceType;
            return (matchesInterface(queryType)) ? queryType : queryType.GetInterfaces().FirstOrDefault(matchesInterface);
        }

#if NETFX_CORE
        public static Type[] GetGenericArguments(this Type type)
        {
            return type.GetTypeInfo().GenericTypeArguments;
        }

        public static Type[] GetInterfaces(this Type type)
        {
            return type.GetTypeInfo().ImplementedInterfaces.ToArray();
        }
#endif

#if NETFX_CORE
        public static bool IsAssignableFrom(this Type type, Type c)
        {
            return type.GetTypeInfo().IsAssignableFrom(c.GetTypeInfo());
        }
#endif

        public static bool IsGenericType(this Type type)
        {
#if NETFX_CORE
            return type.GetTypeInfo().IsGenericType;
#else
            return type.IsGenericType;
#endif
        }

        public static bool IsInterface(this Type type)
        {
#if NETFX_CORE
            return type.GetTypeInfo().IsInterface;
#else
            return type.IsInterface;
#endif
        }

        public static bool IsValueType(this Type type)
        {
#if NETFX_CORE
            return type.GetTypeInfo().IsValueType;
#else
            return type.IsValueType;
#endif
        }
    }
}
