/src/MvcFutures/Mvc/RadioExtensions.cs

namespace Microsoft.Web.Mvc {

    using System;

    using System.Collections;

    using System.Collections.Generic;

    using System.Globalization;

    using System.Linq;

    using System.Web;

    using System.Web.Mvc;

    using System.Web.Mvc.Html;

    using System.Web.Routing;

    using Microsoft.Web.Mvc.Resources;



    [AspNetHostingPermission(System.Security.Permissions.SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]

    public static class RadioListExtensions {

        public static string[] RadioButtonList(this HtmlHelper htmlHelper, string name) {

            return RadioButtonList(htmlHelper, name, (IDictionary<string, object>)null);

        }



        public static string[] RadioButtonList(this HtmlHelper htmlHelper, string name, object htmlAttributes) {

            return RadioButtonList(htmlHelper, name, new RouteValueDictionary(htmlAttributes));

        }



        public static string[] RadioButtonList(this HtmlHelper htmlHelper, string name, IDictionary<string, object> htmlAttributes) {

            SelectList selectList = htmlHelper.GetSelectData(name);

            return htmlHelper.RadioButtonListInternal(name, selectList, true /* usedViewData */, htmlAttributes);

        }



        public static string[] RadioButtonList(this HtmlHelper htmlHelper, string name, SelectList selectList) {

            return RadioButtonList(htmlHelper, name, selectList, (IDictionary<string, object>)null);

        }



        public static string[] RadioButtonList(this HtmlHelper htmlHelper, string name, SelectList selectList, object htmlAttributes) {

            return RadioButtonList(htmlHelper, name, selectList, new RouteValueDictionary(htmlAttributes));

        }



        public static string[] RadioButtonList(this HtmlHelper htmlHelper, string name, SelectList selectList, IDictionary<string, object> htmlAttributes) {

            return htmlHelper.RadioButtonListInternal(name, selectList, false /* usedViewData */, htmlAttributes);

        }



        private static SelectList GetSelectData(this HtmlHelper htmlHelper, string name) {

            object o = null;

            if (htmlHelper.ViewData != null) {

                o = htmlHelper.ViewData.Eval(name);

            }

            if (o == null) {

                throw new InvalidOperationException(

                    String.Format(

                        CultureInfo.CurrentUICulture,

                        MvcResources.HtmlHelper_MissingSelectData,

                        name,

                        typeof(SelectList)));

            }

            SelectList selectList = o as SelectList;

            if (selectList == null) {

                throw new InvalidOperationException(

                    String.Format(

                        CultureInfo.CurrentUICulture,

                        MvcResources.HtmlHelper_WrongSelectDataType,

                        name,

                        o.GetType().FullName,

                        typeof(SelectList)));

            }

            return selectList;

        }



        private static string[] RadioButtonListInternal(this HtmlHelper htmlHelper, string name, SelectList selectList, bool usedViewData, IDictionary<string, object> htmlAttributes) {

            if (String.IsNullOrEmpty(name)) {

                throw new ArgumentException(MvcResources.Common_NullOrEmpty, "name");

            }

            if (selectList == null) {

                throw new ArgumentNullException("selectList");

            }



            // If we haven't already used ViewData to get the entire list of items then we need to

            // use the ViewData-supplied value before using the parameter-supplied value.

            if (!usedViewData) {

                object defaultValue = htmlHelper.ViewData.Eval(name);

                if (defaultValue != null) {

                    selectList = new SelectList(selectList.Items, selectList.DataValueField, selectList.DataTextField, defaultValue);

                }

            }



            // Convert each ListItem to an <option> tag

            IList<ListItem> listItems = selectList.GetListItems();



            IEnumerable<string> radioButtons = listItems.Select<ListItem, string>(item => htmlHelper.RadioButton(name, item.Value, item.Selected, htmlAttributes));



            return radioButtons.ToArray();

        }

    }

}