using System;
using System.Collections.Specialized;
using System.IO;
using System.Web.Hosting;

namespace EPiServer.Extensions
{
	internal static class VirtualPathProviderExtensions
	{
		public static NameValueCollection FixPhysicalPath(this NameValueCollection configParameters)
		{
			var physicalPath = configParameters["physicalPath"] ?? String.Empty;

			if (physicalPath.StartsWith("~"))
			{
				var rootDirectory = (HostingEnvironment.MapPath("~/") ?? Environment.CurrentDirectory).Replace("/", "\\").TrimEnd('\\');
				physicalPath = physicalPath.TrimStart('~', '\\').Replace("/", "\\");

				while (physicalPath.StartsWith(".."))
				{
					rootDirectory = rootDirectory.Substring(0, rootDirectory.LastIndexOf("\\")).TrimEnd('\\');
					physicalPath = physicalPath.TrimStart('.');
					physicalPath = physicalPath.TrimStart('\\');
				}

				physicalPath = Path.Combine(rootDirectory, physicalPath);

				configParameters["physicalPath"] = physicalPath;
			}

			return configParameters;
		}
	}
}