using System;
using System.Collections.Generic;
using System.Linq;

namespace xCommons.Helpers {
    public partial class ObjectHelper {
        /// <summary>
        /// Convert Enum Keys to Array
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public static Array GetKeys<T> () {
            //
            ValidateEnumbType<T> ();
            var type = typeof (T);

            //
            var result = Enum.GetNames (type);

            //
            return result;
        }

        /// <summary>
        /// Convert EnumValues to Array
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public static Array GetValues<T> () {
            //
            ValidateEnumbType<T> ();
            var type = typeof (T);

            //
            var result = Enum.GetValues (type);

            //
            return result;
        }

        /// <summary>
        /// Convert an Enum to IEnumerable of it's Childs
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public static IEnumerable<T> ToEnumerableValues<T> () {
            //
            ValidateEnumbType<T> ();
            var type = typeof (T);

            //
            var result = GetValues<T> ()
                .Cast<T> ();

            //
            return result;
        }

        /// <summary>
        /// Retrieve Keys of an Enumerable
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public static IEnumerable<string> ToEnumerableKeys<T> () {
            //
            ValidateEnumbType<T> ();
            var type = typeof (T);

            //
            var result = GetKeys<T> ()
                .Cast<string> ();

            //
            return result;
        }

        public static IDictionary<string, int> ToDictionary<T> () {
            //
            ValidateEnumbType<T> ();

            //
            var result = new Dictionary<string, int> ();
            foreach (var name in Enum.GetNames (typeof (T))) {
                result.Add (name, (int) Enum.Parse (typeof (T), name));
            }

            //
            return result;
        }

        private static void ValidateEnumbType<T> () {
            //
            var type = typeof (T);
            if (!type.IsEnum) {
                throw new InvalidCastException ();
            }
        }
    }
}