namespace System.Web.Mvc {
    using System;
    using System.Diagnostics.CodeAnalysis;
    using System.Globalization;
    using System.Web.Mvc.Resources;
    using System.Web.Routing;

    public class UrlHelper {
        public UrlHelper(RequestContext requestContext)
            : this(requestContext, RouteTable.Routes) {
        }

        public UrlHelper(RequestContext requestContext, RouteCollection routeCollection) {
            if (requestContext == null) {
                throw new ArgumentNullException("requestContext");
            }
            if (routeCollection == null) {
                throw new ArgumentNullException("routeCollection");
            }
            RequestContext = requestContext;
            RouteCollection = routeCollection;
        }

        public RequestContext RequestContext {
            get;
            private set;
        }

        public RouteCollection RouteCollection {
            get;
            private set;
        }

        public string Action(string actionName) {
            return GenerateUrl(null /* routeName */, actionName, null, (RouteValueDictionary)null /* routeValues */);
        }

        public string Action(string actionName, object routeValues) {
            return GenerateUrl(null /* routeName */, actionName, null /* controllerName */, new RouteValueDictionary(routeValues));
        }

        public string Action(string actionName, RouteValueDictionary routeValues) {
            return GenerateUrl(null /* routeName */, actionName, null /* controllerName */, routeValues);
        }

        public string Action(string actionName, string controllerName) {
            return GenerateUrl(null /* routeName */, actionName, controllerName, (RouteValueDictionary)null /* routeValues */);
        }

        public string Action(string actionName, string controllerName, object routeValues) {
            return GenerateUrl(null /* routeName */, actionName, controllerName, new RouteValueDictionary(routeValues));
        }

        public string Action(string actionName, string controllerName, RouteValueDictionary routeValues) {
            return GenerateUrl(null /* routeName */, actionName, controllerName, routeValues);
        }

        public string Action(string actionName, string controllerName, object routeValues, string protocol) {
            return GenerateUrl(null /* routeName */, actionName, controllerName, protocol, null /* hostName */, null /* fragment */, new RouteValueDictionary(routeValues), RouteCollection, RequestContext, true /* includeImplicitMvcValues */);
        }

        public string Action(string actionName, string controllerName, RouteValueDictionary routeValues, string protocol, string hostName) {
            return GenerateUrl(null /* routeName */, actionName, controllerName, protocol, hostName, null /* fragment */, routeValues, RouteCollection, RequestContext, true /* includeImplicitMvcValues */);
        }

        public string Content(string contentPath) {
            return GenerateContentUrl(contentPath, RequestContext.HttpContext);
        }

        [SuppressMessage("Microsoft.Design", "CA1055:UriReturnValuesShouldNotBeStrings", Justification = "As the return value will used only for rendering, string return value is more appropriate.")]
        public static string GenerateContentUrl(string contentPath, HttpContextBase httpContext) {
            if (String.IsNullOrEmpty(contentPath)) {
                throw new ArgumentException(MvcResources.Common_NullOrEmpty, "contentPath");
            }

            if (httpContext == null) {
                throw new ArgumentNullException("httpContext");
            }

            if (contentPath[0] == '~') {
                return PathHelpers.GenerateClientUrl(httpContext, contentPath);
            }
            else {
                return contentPath;
            }
        }

        //REVIEW: Should we have an overload that takes Uri?
        [SuppressMessage("Microsoft.Design", "CA1054:UriParametersShouldNotBeStrings", Justification = "Needs to take same parameters as HttpUtility.UrlEncode()")]
        [SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification = "For consistency, all helpers are instance methods.")]
        public string Encode(string url) {
            return HttpUtility.UrlEncode(url);
        }

        private string GenerateUrl(string routeName, string actionName, string controllerName, RouteValueDictionary routeValues) {
            return GenerateUrl(routeName, actionName, controllerName, routeValues, RouteCollection, RequestContext, true /* includeImplicitMvcValues */);
        }

        [SuppressMessage("Microsoft.Design", "CA1055:UriReturnValuesShouldNotBeStrings", Justification = "As the return value will used only for rendering, string return value is more appropriate.")]
        public static string GenerateUrl(string routeName, string actionName, string controllerName, string protocol, string hostName, string fragment, RouteValueDictionary routeValues, RouteCollection routeCollection, RequestContext requestContext, bool includeImplicitMvcValues) {
            string url = GenerateUrl(routeName, actionName, controllerName, routeValues, routeCollection, requestContext, includeImplicitMvcValues);

            if (url != null) {
                if (!String.IsNullOrEmpty(fragment)) {
                    url = url + "#" + fragment;
                }

                if (!String.IsNullOrEmpty(protocol) || !String.IsNullOrEmpty(hostName)) {
                    Uri requestUrl = requestContext.HttpContext.Request.Url;
                    protocol = (!String.IsNullOrEmpty(protocol)) ? protocol : Uri.UriSchemeHttp;
                    hostName = (!String.IsNullOrEmpty(hostName)) ? hostName : requestUrl.Host;

                    string port = String.Empty;
                    string requestProtocol = requestUrl.Scheme;

                    if (String.Equals(protocol, requestProtocol, StringComparison.OrdinalIgnoreCase)) {
                        port = requestUrl.IsDefaultPort ? String.Empty : (":" + Convert.ToString(requestUrl.Port, CultureInfo.InvariantCulture));
                    }

                    url = protocol + Uri.SchemeDelimiter + hostName + port + url;
                }
            }

            return url;
        }

        [SuppressMessage("Microsoft.Design", "CA1055:UriReturnValuesShouldNotBeStrings", Justification = "As the return value will used only for rendering, string return value is more appropriate.")]
        public static string GenerateUrl(string routeName, string actionName, string controllerName, RouteValueDictionary routeValues, RouteCollection routeCollection, RequestContext requestContext, bool includeImplicitMvcValues) {
            if (routeCollection == null) {
                throw new ArgumentNullException("routeCollection");
            }

            if (requestContext == null) {
                throw new ArgumentNullException("requestContext");
            }

            RouteValueDictionary mergedRouteValues = RouteValuesHelpers.MergeRouteValues(actionName, controllerName, requestContext.RouteData.Values, routeValues, includeImplicitMvcValues);

            VirtualPathData vpd = routeCollection.GetVirtualPathForArea(requestContext, routeName, mergedRouteValues);
            if (vpd == null) {
                return null;
            }

            string modifiedUrl = PathHelpers.GenerateClientUrl(requestContext.HttpContext, vpd.VirtualPath);
            return modifiedUrl;
        }

        [SuppressMessage("Microsoft.Design", "CA1054:UriParametersShouldNotBeStrings", MessageId = "0#", Justification = "Response.Redirect() takes its URI as a string parameter.")]
        public bool IsLocalUrl(string url) {
            // TODO this should call the System.Web.dll API once it gets added to the framework and MVC takes a dependency on it.
            return System.Web.WebPages.RequestExtensions.IsUrlLocalToHost(RequestContext.HttpContext.Request, url);
        }

        [SuppressMessage("Microsoft.Design", "CA1055:UriReturnValuesShouldNotBeStrings", Justification = "As the return value will used only for rendering, string return value is more appropriate.")]
        public string RouteUrl(object routeValues) {
            return RouteUrl(null /* routeName */, routeValues);
        }

        [SuppressMessage("Microsoft.Design", "CA1055:UriReturnValuesShouldNotBeStrings", Justification = "As the return value will used only for rendering, string return value is more appropriate.")]
        public string RouteUrl(RouteValueDictionary routeValues) {
            return RouteUrl(null /* routeName */, routeValues);
        }

        [SuppressMessage("Microsoft.Design", "CA1055:UriReturnValuesShouldNotBeStrings", Justification = "As the return value will used only for rendering, string return value is more appropriate.")]
        public string RouteUrl(string routeName) {
            return RouteUrl(routeName, (object)null /* routeValues */);
        }

        [SuppressMessage("Microsoft.Design", "CA1055:UriReturnValuesShouldNotBeStrings", Justification = "As the return value will used only for rendering, string return value is more appropriate.")]
        public string RouteUrl(string routeName, object routeValues) {
            return RouteUrl(routeName, routeValues, null /* protocol */);
        }

        [SuppressMessage("Microsoft.Design", "CA1055:UriReturnValuesShouldNotBeStrings", Justification = "As the return value will used only for rendering, string return value is more appropriate.")]
        public string RouteUrl(string routeName, RouteValueDictionary routeValues) {
            return RouteUrl(routeName, routeValues, null /* protocol */, null /* hostName */);
        }

        [SuppressMessage("Microsoft.Design", "CA1055:UriReturnValuesShouldNotBeStrings", Justification = "As the return value will used only for rendering, string return value is more appropriate.")]
        public string RouteUrl(string routeName, object routeValues, string protocol) {
            return GenerateUrl(routeName, null /* actionName */, null /* controllerName */, protocol, null /* hostName */, null /* fragment */, new RouteValueDictionary(routeValues), RouteCollection, RequestContext, false /* includeImplicitMvcValues */);
        }

        [SuppressMessage("Microsoft.Design", "CA1055:UriReturnValuesShouldNotBeStrings", Justification = "As the return value will used only for rendering, string return value is more appropriate.")]
        public string RouteUrl(string routeName, RouteValueDictionary routeValues, string protocol, string hostName) {
            return GenerateUrl(routeName, null /* actionName */, null /* controllerName */, protocol, hostName, null /* fragment */, routeValues, RouteCollection, RequestContext, false /* includeImplicitMvcValues */);
        }
    }
}