using System;
using System.Reflection;
using System.Text.RegularExpressions;
using System.Windows;
using System.Windows.Markup;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace Assets
{
	internal enum ResourceType
	{
		None,
		Xaml,
		Font,
		Image
	}

	[MarkupExtensionReturnType(typeof(object))]
	public class AssetExtension : MarkupExtension
	{
		private static Regex ResourceRegex = new Regex(
			@"
				(?<Image>(\.png|\.jpg|\.bmp)$)
				| (?<Font>\#.+$)
				| (?<Xaml>\.xaml$)
			", 
			RegexOptions.Singleline | RegexOptions.Compiled | RegexOptions.IgnorePatternWhitespace | 
			RegexOptions.IgnoreCase | RegexOptions.CultureInvariant);

		[ConstructorArgument("path")]
		public string Path { get; set; }

		public AssetExtension(string path)
		{
			Path = path;
		}

		public static Uri GetResourceUri(string path)
		{
			string asmName = Assembly.GetExecutingAssembly().GetName().Name;
			string uriString = string.Format("pack://application:,,,/{0};component/{1}", asmName, path);
			Uri uri = new Uri(uriString);

			return uri;
		}

		public override object ProvideValue(IServiceProvider serviceProvider)
		{
			IProvideValueTarget ipvt = serviceProvider.GetService(typeof (IProvideValueTarget)) as IProvideValueTarget;
			if (ipvt == null) return null;

			ResourceType type = ParseResourceType(Path);
			switch (type)
			{
				case ResourceType.Image:
					BitmapImage image = new BitmapImage(GetResourceUri(Path));
					return image;

				case ResourceType.Font:
					FontFamily family = new FontFamily(GetResourceUri(""), Path);
					return family;

				case ResourceType.Xaml:
					return GetResourceUri(Path);
			}

			return null;
		}

		private ResourceType ParseResourceType(string path)
		{
			ResourceType type = ResourceType.None;

			Match match = ResourceRegex.Match(path);
			if (match.Groups["Image"].Success) type = ResourceType.Image;
			else if (match.Groups["Font"].Success) type = ResourceType.Font;
			else if (match.Groups["Xaml"].Success) type = ResourceType.Xaml;

			return type;
		}
	}
}