using System;
using System.Linq;
using System.Text;
using System.Web;
using System.Web.Mvc;
using System.Web.Routing;
using Umbraco.Core;
using Umbraco.Core.Logging;
using Umbraco.Core.Models;
using Umbraco.Web.Models;
using Umbraco.Web.Routing;
using umbraco.cms.businesslogic.template;

namespace Umbraco.Web.Mvc
{
	public class RenderRouteHandler : IRouteHandler
	{
		
		public RenderRouteHandler(IControllerFactory controllerFactory)
		{
			if (controllerFactory == null) throw new ArgumentNullException("controllerFactory");			
			_controllerFactory = controllerFactory;
		}

		/// <summary>
		/// Contructor generally used for unit testing
		/// </summary>
		/// <param name="controllerFactory"></param>
		/// <param name="umbracoContext"></param>
		internal RenderRouteHandler(IControllerFactory controllerFactory, UmbracoContext umbracoContext)
		{
			if (controllerFactory == null) throw new ArgumentNullException("controllerFactory");
			if (umbracoContext == null) throw new ArgumentNullException("umbracoContext");
			_controllerFactory = controllerFactory;
			_umbracoContext = umbracoContext;
		}

		private readonly IControllerFactory _controllerFactory;
		private readonly UmbracoContext _umbracoContext;
		
		/// <summary>
		/// Returns the current UmbracoContext
		/// </summary>
		public UmbracoContext UmbracoContext
		{
			get { return _umbracoContext ?? UmbracoContext.Current; }			
		}

		#region IRouteHandler Members

		/// <summary>
		/// Assigns the correct controller based on the Umbraco request and returns a standard MvcHandler to prcess the response,
		/// this also stores the render model into the data tokens for the current RouteData.
		/// </summary>
		/// <param name="requestContext"></param>
		/// <returns></returns>
		public IHttpHandler GetHttpHandler(RequestContext requestContext)
		{			
			if (UmbracoContext == null)
			{			
				throw new NullReferenceException("There is not current UmbracoContext, it must be initialized before the RenderRouteHandler executes");
			}
			var docRequest = UmbracoContext.PublishedContentRequest;
			if (docRequest == null)
			{
				throw new NullReferenceException("There is not current PublishedContentRequest, it must be initialized before the RenderRouteHandler executes");
			}

			var renderModel = new RenderModel()
			{
				Content = docRequest.PublishedContent,
				CurrentCulture = docRequest.Culture
			};

			//put essential data into the data tokens, the 'umbraco' key is required to be there for the view engine
			requestContext.RouteData.DataTokens.Add("umbraco", renderModel); //required for the RenderModelBinder
			requestContext.RouteData.DataTokens.Add("umbraco-doc-request", docRequest); //required for RenderMvcController
			requestContext.RouteData.DataTokens.Add("umbraco-context", UmbracoContext); //required for UmbracoTemplatePage

			return GetHandlerForRoute(requestContext, docRequest);
			
		}

		#endregion

		/// <summary>
		/// Checks the request and query strings to see if it matches the definition of having a Surface controller
		/// posted value, if so, then we return a PostedDataProxyInfo object with the correct information.
		/// </summary>
		/// <param name="requestContext"></param>
		/// <returns></returns>
		private static PostedDataProxyInfo GetPostedFormInfo(RequestContext requestContext)
		{
			if (requestContext.HttpContext.Request.RequestType != "POST")
				return null;

			//this field will contain a base64 encoded version of the surface route vals 
			if (requestContext.HttpContext.Request["uformpostroutevals"].IsNullOrWhiteSpace())
				return null;

			var encodedVal = requestContext.HttpContext.Request["uformpostroutevals"];
			var decodedString = Encoding.UTF8.GetString(Convert.FromBase64String(encodedVal));
			//the value is formatted as query strings
			var decodedParts = decodedString.Split('&').Select(x => new { Key = x.Split('=')[0], Value = x.Split('=')[1] }).ToArray();

			//validate all required keys exist

			//the controller
			if (!decodedParts.Any(x => x.Key == "c"))
				return null;
			//the action
			if (!decodedParts.Any(x => x.Key == "a"))
				return null;
			//the area
			if (!decodedParts.Any(x => x.Key == "ar"))
				return null;

			////the controller type, if it contains this then it is a plugin controller, not locally declared.
			//if (decodedParts.Any(x => x.Key == "t"))
			//{
			//    return new PostedDataProxyInfo
			//    {
			//        ControllerName = requestContext.HttpContext.Server.UrlDecode(decodedParts.Single(x => x.Key == "c").Value),
			//        ActionName = requestContext.HttpContext.Server.UrlDecode(decodedParts.Single(x => x.Key == "a").Value),
			//        Area = requestContext.HttpContext.Server.UrlDecode(decodedParts.Single(x => x.Key == "ar").Value),
			//        ControllerType = requestContext.HttpContext.Server.UrlDecode(decodedParts.Single(x => x.Key == "t").Value)
			//    };				
			//}

			//return the proxy info without the surface id... could be a local controller.
			return new PostedDataProxyInfo
			{
				ControllerName = requestContext.HttpContext.Server.UrlDecode(decodedParts.Single(x => x.Key == "c").Value),
				ActionName = requestContext.HttpContext.Server.UrlDecode(decodedParts.Single(x => x.Key == "a").Value),
				Area = requestContext.HttpContext.Server.UrlDecode(decodedParts.Single(x => x.Key == "ar").Value),
			};

		}

		/// <summary>
		/// Handles a posted form to an Umbraco Url and ensures the correct controller is routed to and that
		/// the right DataTokens are set.
		/// </summary>
		/// <param name="requestContext"></param>
		/// <param name="postedInfo"></param>
		/// <param name="routeDefinition">The original route definition that would normally be used to route if it were not a POST</param>
		private IHttpHandler HandlePostedValues(RequestContext requestContext, PostedDataProxyInfo postedInfo, RouteDefinition routeDefinition)
		{
			var standardArea = Umbraco.Core.Configuration.GlobalSettings.UmbracoMvcArea;

			//set the standard route values/tokens
			requestContext.RouteData.Values["controller"] = postedInfo.ControllerName;
			requestContext.RouteData.Values["action"] = postedInfo.ActionName;
			requestContext.RouteData.DataTokens["area"] = postedInfo.Area;

			IHttpHandler handler = new MvcHandler(requestContext);

			//ensure the controllerType is set if found, meaning it is a plugin, not locally declared
			if (postedInfo.Area != standardArea)
			{
				//requestContext.RouteData.Values["controllerType"] = postedInfo.ControllerType;
				//find the other data tokens for this route and merge... things like Namespace will be included here
				using (RouteTable.Routes.GetReadLock())
				{
					var surfaceRoute = RouteTable.Routes.OfType<Route>()
						.SingleOrDefault(x => x.Defaults != null &&
						                      x.Defaults.ContainsKey("controller") &&
						                      x.Defaults["controller"].ToString() == postedInfo.ControllerName &&
						                      x.DataTokens.ContainsKey("area") &&
						                      x.DataTokens["area"].ToString() == postedInfo.Area);
					if (surfaceRoute == null)
						throw new InvalidOperationException("Could not find a Surface controller route in the RouteTable for controller name " + postedInfo.ControllerName + " and within the area of " + postedInfo.Area);
					//set the 'Namespaces' token so the controller factory knows where to look to construct it
					if (surfaceRoute.DataTokens.ContainsKey("Namespaces"))
					{
						requestContext.RouteData.DataTokens["Namespaces"] = surfaceRoute.DataTokens["Namespaces"];
					}
					handler = surfaceRoute.RouteHandler.GetHttpHandler(requestContext);
				}

			}

			//store the original URL this came in on
			requestContext.RouteData.DataTokens["umbraco-item-url"] = requestContext.HttpContext.Request.Url.AbsolutePath;
			//store the original route definition
			requestContext.RouteData.DataTokens["umbraco-route-def"] = routeDefinition;

			return handler;
		}

		/// <summary>
		/// Returns a RouteDefinition object based on the current renderModel
		/// </summary>
		/// <param name="requestContext"></param>
		/// <param name="publishedContentRequest"></param>
		/// <returns></returns>
		internal virtual RouteDefinition GetUmbracoRouteDefinition(RequestContext requestContext, PublishedContentRequest publishedContentRequest)
		{
			var defaultControllerName = ControllerExtensions.GetControllerName<RenderMvcController>();
			//creates the default route definition which maps to the 'UmbracoController' controller
			var def = new RouteDefinition
				{
					ControllerName = defaultControllerName,
					Controller = new RenderMvcController(),
					PublishedContentRequest = publishedContentRequest,
					ActionName = ((Route)requestContext.RouteData.Route).Defaults["action"].ToString(),
					HasHijackedRoute = false
				};

			//check if there's a custom controller assigned, base on the document type alias.
			var controller = _controllerFactory.CreateController(requestContext, publishedContentRequest.PublishedContent.DocumentTypeAlias);


			//check if that controller exists
			if (controller != null)
			{

				//ensure the controller is of type 'RenderMvcController'
				if (controller is RenderMvcController)
				{
					//set the controller and name to the custom one
					def.Controller = (ControllerBase)controller;
					def.ControllerName = ControllerExtensions.GetControllerName(controller.GetType());
					if (def.ControllerName != defaultControllerName)
					{
						def.HasHijackedRoute = true;	
					}
				}
				else
				{
					LogHelper.Warn<RenderRouteHandler>("The current Document Type {0} matches a locally declared controller of type {1}. Custom Controllers for Umbraco routing must inherit from '{2}'.", publishedContentRequest.PublishedContent.DocumentTypeAlias, controller.GetType().FullName, typeof(RenderMvcController).FullName);
					//exit as we cannnot route to the custom controller, just route to the standard one.
					return def;
				}

				//check that a template is defined), if it doesn't and there is a hijacked route it will just route
				// to the index Action
				if (publishedContentRequest.HasTemplate)
				{
					//check if the custom controller has an action with the same name as the template name (we convert ToUmbracoAlias since the template name might have invalid chars).
					//NOTE: This also means that all custom actions MUST be PascalCase.. but that should be standard.
					var templateName = publishedContentRequest.Template.Alias.Split('.')[0].ToUmbracoAlias(StringAliasCaseType.PascalCase);
					def.ActionName = templateName;
				}
	
			}
			

			return def;
		}

		/// <summary>
		/// this will determine the controller and set the values in the route data
		/// </summary>
		/// <param name="requestContext"></param>
		/// <param name="publishedContentRequest"></param>
		internal IHttpHandler GetHandlerForRoute(RequestContext requestContext, PublishedContentRequest publishedContentRequest)
		{
			var routeDef = GetUmbracoRouteDefinition(requestContext, publishedContentRequest);

			//Need to check for a special case if there is form data being posted back to an Umbraco URL
			var postedInfo = GetPostedFormInfo(requestContext);
			if (postedInfo != null)
			{
				return HandlePostedValues(requestContext, postedInfo, routeDef);
			}

			//here we need to check if there is no hijacked route and no template assigned, if this is the case
			//we want to return a blank page, but we'll leave that up to the NoTemplateHandler.
			if (!publishedContentRequest.HasTemplate && !routeDef.HasHijackedRoute)
			{
				var handler = publishedContentRequest.ProcessNoTemplateInMvc(requestContext.HttpContext);

				// if it's not null it can be either the PublishedContentNotFoundHandler (no document was
				// found to handle 404, or document with no template was found) or the WebForms handler 
				// (a document was found and its template is WebForms)

				// if it's null it means that a document was found and its template is Mvc

				// if we have a handler, return now
				if (handler != null)
					return handler;

				// else we are running Mvc
				// update the route definition
				routeDef = GetUmbracoRouteDefinition(requestContext, publishedContentRequest);
			}

			//no post values, just route to the controller/action requried (local)

			requestContext.RouteData.Values["controller"] = routeDef.ControllerName;
			if (!string.IsNullOrWhiteSpace(routeDef.ActionName))
			{
				requestContext.RouteData.Values["action"] = routeDef.ActionName;
			}

			// reset the friendly path so in the controllers and anything occuring after this point in time,
			//the URL is reset back to the original request.
			requestContext.HttpContext.RewritePath(UmbracoContext.OriginalRequestUrl.PathAndQuery);

			return new MvcHandler(requestContext);
		}
	}
}