/*
 *
 * (c) Copyright Ascensio System Limited 2010-2018
 *
 * This program is freeware. You can redistribute it and/or modify it under the terms of the GNU 
 * General Public License (GPL) version 3 as published by the Free Software Foundation (https://www.gnu.org/copyleft/gpl.html). 
 * In accordance with Section 7(a) of the GNU GPL its Section 15 shall be amended to the effect that 
 * Ascensio System SIA expressly excludes the warranty of non-infringement of any third-party rights.
 *
 * THIS PROGRAM IS DISTRIBUTED WITHOUT ANY WARRANTY; WITHOUT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY OR
 * FITNESS FOR A PARTICULAR PURPOSE. For more details, see GNU GPL at https://www.gnu.org/copyleft/gpl.html
 *
 * You can contact Ascensio System SIA by email at sales@onlyoffice.com
 *
 * The interactive user interfaces in modified source and object code versions of ONLYOFFICE must display 
 * Appropriate Legal Notices, as required under Section 5 of the GNU GPL version 3.
 *
 * Pursuant to Section 7 § 3(b) of the GNU GPL you must retain the original ONLYOFFICE logo which contains 
 * relevant author attributions when distributing the software. If the display of the logo in its graphic 
 * form is not reasonably feasible for technical reasons, you must include the words "Powered by ONLYOFFICE" 
 * in every copy of the program you distribute. 
 * Pursuant to Section 7 § 3(e) we decline to grant you any rights under trademark law for use of our trademarks.
 *
*/


using System;
using System.Text.RegularExpressions;
using ASC.Common.Caching;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;

namespace ASC.Web.Core.Mobile
{
    public class MobileDetector
    {
        private readonly Regex uaMobileRegex;

        private static readonly ICache cache = AscCache.Memory;

        public IHttpContextAccessor HttpContextAccessor { get; }

        public bool IsMobile()
        {
            return IsRequestMatchesMobile();
        }


        public MobileDetector(IHttpContextAccessor httpContextAccessor, IConfiguration configuration)
        {
            if (!string.IsNullOrEmpty(configuration["mobile:regex"]))
            {
                uaMobileRegex = new Regex(configuration["mobile:regex"], RegexOptions.IgnoreCase | RegexOptions.Singleline | RegexOptions.Compiled);
            }

            HttpContextAccessor = httpContextAccessor;
        }


        public bool IsRequestMatchesMobile()
        {
            bool? result = false;
            var ua = HttpContextAccessor.HttpContext.Request.Headers["User-Agent"].ToString();
            var regex = uaMobileRegex;
            if (!string.IsNullOrEmpty(ua) && regex != null)
            {
                var key = "mobileDetector/" + ua.GetHashCode();


                if (bool.TryParse(cache.Get<string>(key), out var fromCache))
                {
                    result = fromCache;
                }
                else
                {
                    cache.Insert(key, (result = regex.IsMatch(ua)).ToString(), TimeSpan.FromMinutes(10));
                }
            }
            return result.GetValueOrDefault();
        }
    }
}