﻿// Copyright (c) 2017 Sidneys1
//
// 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.ComponentModel;
using System.Linq;
using System.Windows.Markup;

namespace BatchImageProcessor.ViewModel.Extensions
{
	public class EnumerationExtension : MarkupExtension
	{
		private Type _enumType;

		public EnumerationExtension(Type enumType)
		{
			if (enumType == null)
				throw new ArgumentNullException(nameof(enumType));

			EnumType = enumType;
		}

		public Type EnumType
		{
			get { return _enumType; }
			private set
			{
				if (_enumType == value)
					return;

				var enumType = Nullable.GetUnderlyingType(value) ?? value;

				if (enumType.IsEnum == false)
					throw new ArgumentException("Type must be an Enum.");

				_enumType = value;
			}
		}

		public override object ProvideValue(IServiceProvider serviceProvider)
		{
			var enumValues = Enum.GetValues(EnumType);

			return (
				from object enumValue in enumValues
				select new EnumerationMember
				{
					Value = enumValue,
					Description = GetDescription(enumValue)
				}).ToArray();
		}

		private string GetDescription(object enumValue)
		{
			var descriptionAttribute = EnumType
				.GetField(enumValue.ToString())
				.GetCustomAttributes(typeof(DescriptionAttribute), false)
				.FirstOrDefault() as DescriptionAttribute;


			return descriptionAttribute != null
				? descriptionAttribute.Description
				: enumValue.ToString();
		}

		public class EnumerationMember
		{
			public string Description { get; set; }
			public object Value { get; set; }
		}
	}

}
