// Author: Richard Garside [www.nogginbox.co.uk]
// Ref: http://www.nogginbox.co.uk/blog/xml-to-asp.net-mvc-action-method

namespace NogginBox.MvcExtras.Providers
{
	using System;
	using System.Collections;
	using System.Collections.Generic;
	using System.Globalization;
	using System.Web.Mvc;
	using System.Xml;
	using System.Xml.Linq;

	public class XmlValueProviderFactory : ValueProviderFactory
	{
		private static void AddToBackingStore(Dictionary<string, object> backingStore, string prefix, XElement xmlDoc)
		{
			// Check the keys to see if this is an array or an object
			var uniqueKeys = new List<String>();
			int totalCount = 0;
			foreach (XElement element in xmlDoc.Elements())
			{
				if(!uniqueKeys.Contains(element.Name.LocalName)) {
					uniqueKeys.Add(element.Name.LocalName);
				}
				totalCount++;
			}

			bool isArray;
			if (uniqueKeys.Count == 1) {
				isArray = true;
			}
			else if (uniqueKeys.Count == totalCount) {
				isArray = false;
			}
			else {
				// Not sure how to deal with a XML doc that has some keys the same, but not all
				// For now don't process this node
				return;
			}

			// Add the elements to the backing store
			int elementCount = 0;
			foreach (XElement element in xmlDoc.Elements())
			{
				if (element.HasElements)
				{
					if (isArray)
					{
						// Omit local name for arrays and add index instead
						AddToBackingStore(backingStore, String.Format("{0}[{1}]", prefix, elementCount), element);
					}
					else
					{
						AddToBackingStore(backingStore, MakePropertyKey(prefix, element.Name.LocalName), element);
					}
				}
				else
				{
					backingStore.Add(MakePropertyKey(prefix, element.Name.LocalName), element.Value);
				}

				elementCount++;
			}
		}

		private static XDocument GetDeserializedXml(ControllerContext controllerContext) {
			var contentType = controllerContext.HttpContext.Request.ContentType;
			if (!contentType.StartsWith("text/xml", StringComparison.OrdinalIgnoreCase)
				&& !contentType.StartsWith("application/xml", StringComparison.OrdinalIgnoreCase)) {
				// Are there any other XML mime types that are used? (Add them here)

				// not XML request
				return null;
			}


			XDocument xml;
			try
			{
				var xmlReader = new XmlTextReader(controllerContext.HttpContext.Request.InputStream);
				xml = XDocument.Load(xmlReader);
			}
			catch (Exception)
			{
				return null;
			}


			if (xml.FirstNode == null)
			{
				// No XML data
				return null;
			}

			return xml;
		}

		public override IValueProvider GetValueProvider(ControllerContext controllerContext) {
			XDocument xmlData = GetDeserializedXml(controllerContext);
			if (xmlData == null) {
				return null;
			}

			Dictionary<string, object> backingStore = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);
			AddToBackingStore(backingStore, String.Empty, xmlData.Root);
			return new DictionaryValueProvider<object>(backingStore, CultureInfo.CurrentCulture);
		}

		private static string MakeArrayKey(string prefix, int index) {
			return prefix + "[" + index.ToString(CultureInfo.InvariantCulture) + "]";
		}

		private static string MakePropertyKey(string prefix, string propertyName) {
			return (String.IsNullOrEmpty(prefix)) ? propertyName : prefix + "." + propertyName;
		}
	}
}