/*
 *
 * (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.Collections.Generic;
using System.Linq;

using ASC.Common;
using ASC.Common.Security;
using ASC.Common.Security.Authorizing;
using ASC.Core.Caching;

namespace ASC.Core
{
    [Scope]
    public class AuthorizationManager
    {
        private readonly IAzService service;

        private TenantManager TenantManager { get; }

        public AuthorizationManager(IAzService service, TenantManager tenantManager)
        {
            this.service = service;
            TenantManager = tenantManager;
        }


        public IEnumerable<AzRecord> GetAces(Guid subjectId, Guid actionId)
        {
            var aces = service.GetAces(TenantManager.GetCurrentTenant().TenantId, default);
            return aces
                .Where(a => a.ActionId == actionId && (a.SubjectId == subjectId || subjectId == Guid.Empty))
                .ToList();
        }

        public IEnumerable<AzRecord> GetAces(Guid subjectId, Guid actionId, ISecurityObjectId objectId)
        {
            var aces = service.GetAces(TenantManager.GetCurrentTenant().TenantId, default);
            return FilterAces(aces, subjectId, actionId, objectId)
                .ToList();
        }

        public IEnumerable<AzRecord> GetAcesWithInherits(Guid subjectId, Guid actionId, ISecurityObjectId objectId, ISecurityObjectProvider secObjProvider)
        {
            if (objectId == null)
            {
                return GetAces(subjectId, actionId, null);
            }

            var result = new List<AzRecord>();
            var aces = service.GetAces(TenantManager.GetCurrentTenant().TenantId, default);
            result.AddRange(FilterAces(aces, subjectId, actionId, objectId));

            var inherits = new List<AzRecord>();
            var secObjProviderHelper = new AzObjectSecurityProviderHelper(objectId, secObjProvider);
            while (secObjProviderHelper.NextInherit())
            {
                inherits.AddRange(FilterAces(aces, subjectId, actionId, secObjProviderHelper.CurrentObjectId));
            }

            inherits.AddRange(FilterAces(aces, subjectId, actionId, null));

            result.AddRange(DistinctAces(inherits));
            return result;
        }

        public void AddAce(AzRecord r)
        {
            service.SaveAce(TenantManager.GetCurrentTenant().TenantId, r);
        }

        public void RemoveAce(AzRecord r)
        {
            service.RemoveAce(TenantManager.GetCurrentTenant().TenantId, r);
        }

        public void RemoveAllAces(ISecurityObjectId id)
        {
            foreach (var r in GetAces(Guid.Empty, Guid.Empty, id))
            {
                RemoveAce(r);
            }
        }

        private IEnumerable<AzRecord> GetAcesInternal()
        {
            return service.GetAces(TenantManager.GetCurrentTenant().TenantId, default);
        }

        private IEnumerable<AzRecord> DistinctAces(IEnumerable<AzRecord> inheritAces)
        {
            var aces = new Dictionary<string, AzRecord>();
            foreach (var a in inheritAces)
            {
                aces[string.Format("{0}{1}{2:D}", a.SubjectId, a.ActionId, a.Reaction)] = a;
            }
            return aces.Values;
        }

        private IEnumerable<AzRecord> FilterAces(IEnumerable<AzRecord> aces, Guid subjectId, Guid actionId, ISecurityObjectId objectId)
        {
            var objId = AzObjectIdHelper.GetFullObjectId(objectId);
            return aces is AzRecordStore store ?
                store.Get(objId).Where(a => (a.SubjectId == subjectId || subjectId == Guid.Empty) && (a.ActionId == actionId || actionId == Guid.Empty)) :
                aces.Where(a => (a.SubjectId == subjectId || subjectId == Guid.Empty) && (a.ActionId == actionId || actionId == Guid.Empty) && a.ObjectId == objId);
        }
    }
}