/src/ZebraFlickr/CommandLine/EnumArgumentDecoder.cs

#region License



// Copyright (c) 2012 Gareth Lennox (garethl@dwakn.com)

// All rights reserved.

// 

// Redistribution and use in source and binary forms, with or without modification,

// are permitted provided that the following conditions are met:

// 

//     * Redistributions of source code must retain the above copyright notice,

//       this list of conditions and the following disclaimer.

//     * Redistributions in binary form must reproduce the above copyright notice,

//       this list of conditions and the following disclaimer in the documentation

//       and/or other materials provided with the distribution.

//     * Neither the name of Gareth Lennox nor the names of its

//       contributors may be used to endorse or promote products derived from this

//       software without specific prior written permission.

//  

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND

// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE

// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR

// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER

// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,

// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

// THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.



#endregion



using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Reflection;

using System.Text;



namespace ZebraFlickr.CommandLine

{

	public class EnumArgumentDecoder : IArgumentDecoder

	{

		private ArgumentMap _map;



		#region Implementation of IArgumentDecoder



		/// <summary>

		/// Decode an argument

		/// </summary>

		/// <param name="item">Item to set the argument on</param>

		/// <param name="argument">The argument</param>

		public void Decode(object item, Parser.Argument argument)

		{

			var enumType = _map.Property.PropertyType;

			var enumValue = Enum.Parse(enumType, argument.Value, true);



			_map.Property.SetValue(item, enumValue, null);

		}



		/// <summary>

		/// Initialize the decoder with the map

		/// </summary>

		/// <param name="map">The argument map</param>

		public void Initialize(ArgumentMap map)

		{

			_map = map;



			var enumType = _map.Property.PropertyType;



			var names = GetNames(enumType);





			var defaultDescription = "";



			if (map.Default != null)

			{

				var values = Enum.GetValues(enumType);



				for (int x = 0; x < values.Length; x++)

				{

					if (values.GetValue(x).Equals(map.Default))

					{

						defaultDescription = names[x];

						break;

					}

				}



				if (!string.IsNullOrEmpty(defaultDescription))

				{

					defaultDescription = ". Default = " + defaultDescription;

				}

			}



			var descriptionAddition = string.Format(" ({0}){1}", FancyJoin(", ", " or ", names), defaultDescription);



			_map.Description += descriptionAddition;

		}



		/// <summary>

		/// Did the decoder find a value?

		/// </summary>

		public bool HasValue

		{

			get { return true; }

		}



		private static string FancyJoin(string separator, string lastSeparator, string[] values)

		{

			if (values.Length == 0)

				return string.Empty;



			if (values.Length == 1)

				return values[0];





			var sb = new StringBuilder();



			for (int x = 0; x < values.Length; x++)

			{

				if (x > 0)

				{

					if (x < values.Length - 1)

						sb.Append(separator);

					else

						sb.Append(lastSeparator);

				}



				sb.Append(values[x]);

			}



			return sb.ToString();

		}



		private static string[] GetNames(Type type)

		{

			var ret = new List<string>();



			var fields = type.GetFields(BindingFlags.Public | BindingFlags.Static);



			foreach (var field in fields)

			{

				var attribs = field.GetCustomAttributes(typeof (DescriptionAttribute), true);



				string name;



				if (attribs.Length > 0)

				{

					name = ((DescriptionAttribute) attribs[0]).Description;

				}

				else

				{

					name = field.Name;

				}



				ret.Add(name);

			}



			return ret.ToArray();

		}



		#endregion

	}

}