// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Globalization;
using System.Text.RegularExpressions;
using Microsoft.AspNet.Http;

namespace Microsoft.AspNet.Routing.Constraints
{
    public class RegexRouteConstraint : IRouteConstraint
    {
        private static readonly TimeSpan RegexMatchTimeout = TimeSpan.FromSeconds(10);

        public RegexRouteConstraint(Regex regex)
        {
            if (regex == null)
            {
                throw new ArgumentNullException(nameof(regex));
            }

            Constraint = regex;
        }

        public RegexRouteConstraint(string regexPattern)
        {
            if (regexPattern == null)
            {
                throw new ArgumentNullException(nameof(regexPattern));
            }

            Constraint = new Regex(
                regexPattern,
                RegexOptions.CultureInvariant | RegexOptions.IgnoreCase,
                RegexMatchTimeout);
        }

        public Regex Constraint { get; private set; }

        public bool Match(
            HttpContext httpContext,
            IRouter route,
            string routeKey,
            RouteValueDictionary values,
            RouteDirection routeDirection)
        {
            if (httpContext == null)
            {
                throw new ArgumentNullException(nameof(httpContext));
            }

            if (route == null)
            {
                throw new ArgumentNullException(nameof(route));
            }

            if (routeKey == null)
            {
                throw new ArgumentNullException(nameof(routeKey));
            }

            if (values == null)
            {
                throw new ArgumentNullException(nameof(values));
            }

            object routeValue;

            if (values.TryGetValue(routeKey, out routeValue)
                && routeValue != null)
            {
                var parameterValueString = Convert.ToString(routeValue, CultureInfo.InvariantCulture);

                return Constraint.IsMatch(parameterValueString);
            }

            return false;
        }
    }
}