namespace System.Web.Mvc.Html {
    using System.Collections.Generic;
    using System.Diagnostics.CodeAnalysis;
    using System.Web.Routing;

    public static class FormExtensions {
        public static MvcForm BeginForm(this HtmlHelper htmlHelper) {
            // generates <form action="{current url}" method="post">...</form>
            string formAction = htmlHelper.ViewContext.HttpContext.Request.RawUrl;
            return FormHelper(htmlHelper, formAction, FormMethod.Post, new RouteValueDictionary());
        }

        public static MvcForm BeginForm(this HtmlHelper htmlHelper, object routeValues) {
            return BeginForm(htmlHelper, null, null, new RouteValueDictionary(routeValues), FormMethod.Post, new RouteValueDictionary());
        }

        public static MvcForm BeginForm(this HtmlHelper htmlHelper, RouteValueDictionary routeValues) {
            return BeginForm(htmlHelper, null, null, routeValues, FormMethod.Post, new RouteValueDictionary());
        }

        public static MvcForm BeginForm(this HtmlHelper htmlHelper, string actionName, string controllerName) {
            return BeginForm(htmlHelper, actionName, controllerName, new RouteValueDictionary(), FormMethod.Post, new RouteValueDictionary());
        }

        public static MvcForm BeginForm(this HtmlHelper htmlHelper, string actionName, string controllerName, object routeValues) {
            return BeginForm(htmlHelper, actionName, controllerName, new RouteValueDictionary(routeValues), FormMethod.Post, new RouteValueDictionary());
        }

        public static MvcForm BeginForm(this HtmlHelper htmlHelper, string actionName, string controllerName, RouteValueDictionary routeValues) {
            return BeginForm(htmlHelper, actionName, controllerName, routeValues, FormMethod.Post, new RouteValueDictionary());
        }

        public static MvcForm BeginForm(this HtmlHelper htmlHelper, string actionName, string controllerName, FormMethod method) {
            return BeginForm(htmlHelper, actionName, controllerName, new RouteValueDictionary(), method, new RouteValueDictionary());
        }

        public static MvcForm BeginForm(this HtmlHelper htmlHelper, string actionName, string controllerName, object routeValues, FormMethod method) {
            return BeginForm(htmlHelper, actionName, controllerName, new RouteValueDictionary(routeValues), method, new RouteValueDictionary());
        }

        public static MvcForm BeginForm(this HtmlHelper htmlHelper, string actionName, string controllerName, RouteValueDictionary routeValues, FormMethod method) {
            return BeginForm(htmlHelper, actionName, controllerName, routeValues, method, new RouteValueDictionary());
        }

        public static MvcForm BeginForm(this HtmlHelper htmlHelper, string actionName, string controllerName, FormMethod method, object htmlAttributes) {
            return BeginForm(htmlHelper, actionName, controllerName, new RouteValueDictionary(), method, HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes));
        }

        public static MvcForm BeginForm(this HtmlHelper htmlHelper, string actionName, string controllerName, FormMethod method, IDictionary<string, object> htmlAttributes) {
            return BeginForm(htmlHelper, actionName, controllerName, new RouteValueDictionary(), method, htmlAttributes);
        }

        public static MvcForm BeginForm(this HtmlHelper htmlHelper, string actionName, string controllerName, object routeValues, FormMethod method, object htmlAttributes) {
            return BeginForm(htmlHelper, actionName, controllerName, new RouteValueDictionary(routeValues), method, HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes));
        }

        public static MvcForm BeginForm(this HtmlHelper htmlHelper, string actionName, string controllerName, RouteValueDictionary routeValues, FormMethod method, IDictionary<string, object> htmlAttributes) {
            string formAction = UrlHelper.GenerateUrl(null /* routeName */, actionName, controllerName, routeValues, htmlHelper.RouteCollection, htmlHelper.ViewContext.RequestContext, true /* includeImplicitMvcValues */);
            return FormHelper(htmlHelper, formAction, method, htmlAttributes);
        }

        public static MvcForm BeginRouteForm(this HtmlHelper htmlHelper, object routeValues) {
            return BeginRouteForm(htmlHelper, null /* routeName */, new RouteValueDictionary(routeValues), FormMethod.Post, new RouteValueDictionary());
        }

        public static MvcForm BeginRouteForm(this HtmlHelper htmlHelper, RouteValueDictionary routeValues) {
            return BeginRouteForm(htmlHelper, null /* routeName */, routeValues, FormMethod.Post, new RouteValueDictionary());
        }

        public static MvcForm BeginRouteForm(this HtmlHelper htmlHelper, string routeName) {
            return BeginRouteForm(htmlHelper, routeName, new RouteValueDictionary(), FormMethod.Post, new RouteValueDictionary());
        }

        public static MvcForm BeginRouteForm(this HtmlHelper htmlHelper, string routeName, object routeValues) {
            return BeginRouteForm(htmlHelper, routeName, new RouteValueDictionary(routeValues), FormMethod.Post, new RouteValueDictionary());
        }

        public static MvcForm BeginRouteForm(this HtmlHelper htmlHelper, string routeName, RouteValueDictionary routeValues) {
            return BeginRouteForm(htmlHelper, routeName, routeValues, FormMethod.Post, new RouteValueDictionary());
        }

        public static MvcForm BeginRouteForm(this HtmlHelper htmlHelper, string routeName, FormMethod method) {
            return BeginRouteForm(htmlHelper, routeName, new RouteValueDictionary(), method, new RouteValueDictionary());
        }

        public static MvcForm BeginRouteForm(this HtmlHelper htmlHelper, string routeName, object routeValues, FormMethod method) {
            return BeginRouteForm(htmlHelper, routeName, new RouteValueDictionary(routeValues), method, new RouteValueDictionary());
        }

        public static MvcForm BeginRouteForm(this HtmlHelper htmlHelper, string routeName, RouteValueDictionary routeValues, FormMethod method) {
            return BeginRouteForm(htmlHelper, routeName, routeValues, method, new RouteValueDictionary());
        }

        public static MvcForm BeginRouteForm(this HtmlHelper htmlHelper, string routeName, FormMethod method, object htmlAttributes) {
            return BeginRouteForm(htmlHelper, routeName, new RouteValueDictionary(), method, HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes));
        }

        public static MvcForm BeginRouteForm(this HtmlHelper htmlHelper, string routeName, FormMethod method, IDictionary<string, object> htmlAttributes) {
            return BeginRouteForm(htmlHelper, routeName, new RouteValueDictionary(), method, htmlAttributes);
        }

        public static MvcForm BeginRouteForm(this HtmlHelper htmlHelper, string routeName, object routeValues, FormMethod method, object htmlAttributes) {
            return BeginRouteForm(htmlHelper, routeName, new RouteValueDictionary(routeValues), method, HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes));
        }

        public static MvcForm BeginRouteForm(this HtmlHelper htmlHelper, string routeName, RouteValueDictionary routeValues, FormMethod method, IDictionary<string, object> htmlAttributes) {
            string formAction = UrlHelper.GenerateUrl(routeName, null, null, routeValues, htmlHelper.RouteCollection, htmlHelper.ViewContext.RequestContext, false /* includeImplicitMvcValues */);
            return FormHelper(htmlHelper, formAction, method, htmlAttributes);
        }

        public static void EndForm(this HtmlHelper htmlHelper) {
            htmlHelper.ViewContext.Writer.Write("</form>");
            htmlHelper.ViewContext.OutputClientValidation();
        }

        [SuppressMessage("Microsoft.Reliability", "CA2000:Dispose objects before losing scope", Justification = "Because disposing the object would write to the response stream, you don't want to prematurely dispose of this object.")]
        private static MvcForm FormHelper(this HtmlHelper htmlHelper, string formAction, FormMethod method, IDictionary<string, object> htmlAttributes) {
            TagBuilder tagBuilder = new TagBuilder("form");
            tagBuilder.MergeAttributes(htmlAttributes);
            // action is implicitly generated, so htmlAttributes take precedence.
            tagBuilder.MergeAttribute("action", formAction);
            // method is an explicit parameter, so it takes precedence over the htmlAttributes.
            tagBuilder.MergeAttribute("method", HtmlHelper.GetFormMethodString(method), true);

            bool traditionalJavascriptEnabled = htmlHelper.ViewContext.ClientValidationEnabled
                                            && !htmlHelper.ViewContext.UnobtrusiveJavaScriptEnabled;

            if (traditionalJavascriptEnabled) {
                // forms must have an ID for client validation
                tagBuilder.GenerateId(htmlHelper.ViewContext.FormIdGenerator());
            }

            htmlHelper.ViewContext.Writer.Write(tagBuilder.ToString(TagRenderMode.StartTag));
            MvcForm theForm = new MvcForm(htmlHelper.ViewContext);

            if (traditionalJavascriptEnabled) {
                htmlHelper.ViewContext.FormContext.FormId = tagBuilder.Attributes["id"];
            }

            return theForm;
        }
    }
}