// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.

using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Reflection;
using System.Web.Mvc.Properties;

namespace System.Web.Mvc
{
    [SuppressMessage("Microsoft.Design", "CA1019:DefineAccessorsForAttributeArguments", Justification = "The accessor is exposed as an ICollection<string>.")]
    [AttributeUsage(AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
    public sealed class AcceptVerbsAttribute : ActionMethodSelectorAttribute
    {
        public AcceptVerbsAttribute(HttpVerbs verbs)
            : this(EnumToArray(verbs))
        {
        }

        public AcceptVerbsAttribute(params string[] verbs)
        {
            if (verbs == null || verbs.Length == 0)
            {
                throw new ArgumentException(MvcResources.Common_NullOrEmpty, "verbs");
            }

            Verbs = new ReadOnlyCollection<string>(verbs);
        }

        public ICollection<string> Verbs { get; private set; }

        private static void AddEntryToList(HttpVerbs verbs, HttpVerbs match, List<string> verbList, string entryText)
        {
            if ((verbs & match) != 0)
            {
                verbList.Add(entryText);
            }
        }

        internal static string[] EnumToArray(HttpVerbs verbs)
        {
            List<string> verbList = new List<string>();

            AddEntryToList(verbs, HttpVerbs.Get, verbList, "GET");
            AddEntryToList(verbs, HttpVerbs.Post, verbList, "POST");
            AddEntryToList(verbs, HttpVerbs.Put, verbList, "PUT");
            AddEntryToList(verbs, HttpVerbs.Delete, verbList, "DELETE");
            AddEntryToList(verbs, HttpVerbs.Head, verbList, "HEAD");
            AddEntryToList(verbs, HttpVerbs.Patch, verbList, "PATCH");
            AddEntryToList(verbs, HttpVerbs.Options, verbList, "OPTIONS");

            return verbList.ToArray();
        }

        public override bool IsValidForRequest(ControllerContext controllerContext, MethodInfo methodInfo)
        {
            if (controllerContext == null)
            {
                throw new ArgumentNullException("controllerContext");
            }

            string incomingVerb = controllerContext.HttpContext.Request.GetHttpMethodOverride();

            return Verbs.Contains(incomingVerb, StringComparer.OrdinalIgnoreCase);
        }
    }
}
