/*
 *
 * (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 ASC.Common.Data;
using ASC.Common.Data.Sql;
using ASC.Common.Data.Sql.Expressions;
using ASC.Common.Security.Authorizing;
using ASC.Core.Tenants;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Linq;

namespace ASC.Core.Data
{
    public class DbAzService : DbBaseService, IAzService
    {
        public DbAzService(ConnectionStringSettings connectionString)
            : base(connectionString, "tenant")
        {
        }

        public IEnumerable<AzRecord> GetAces(int tenant, DateTime from)
        {
            // row with tenant = -1 - common for all tenants, but equal row with tenant != -1 escape common row for the portal
            var q = new SqlQuery("core_acl")
                .Select("subject", "action", "object", "acetype")
                .Where(Exp.Eq("tenant", Tenant.DEFAULT_TENANT));

            var commonAces = ExecList(q)
                .ConvertAll(r => ToAzRecord(r, tenant))
                .ToDictionary(a => string.Concat(a.Tenant.ToString(), a.SubjectId.ToString(), a.ActionId.ToString(), a.ObjectId));

            q = new SqlQuery("core_acl")
                .Select("subject", "action", "object", "acetype")
                .Where(Exp.Eq("tenant", tenant));

            var tenantAces = ExecList(q)
                .ConvertAll(r => new AzRecord(new Guid((string)r[0]), new Guid((string)r[1]), (AceType)Convert.ToInt32(r[3]), string.Empty.Equals(r[2]) ? null : (string)r[2]) { Tenant = tenant });

            // remove excaped rows
            foreach (var a in tenantAces.ToList())
            {
                var key = string.Concat(a.Tenant.ToString(), a.SubjectId.ToString(), a.ActionId.ToString(), a.ObjectId);
                if (commonAces.ContainsKey(key))
                {
                    var common = commonAces[key];
                    commonAces.Remove(key);
                    if (common.Reaction == a.Reaction)
                    {
                        tenantAces.Remove(a);
                    }
                }
            }

            return commonAces.Values.Concat(tenantAces);
        }

        public AzRecord SaveAce(int tenant, AzRecord r)
        {
            r.Tenant = tenant;
            using (var db = GetDb())
            using (var tx = db.BeginTransaction())
            {
                if (!ExistEscapeRecord(db, r))
                {
                    InsertRecord(db, r);
                }
                else
                {
                    // unescape
                    DeleteRecord(db, r);
                }
                tx.Commit();
            }

            return r;
        }

        public void RemoveAce(int tenant, AzRecord r)
        {
            r.Tenant = tenant;
            using (var db = GetDb())
            using (var tx = db.BeginTransaction())
            {
                if (ExistEscapeRecord(db, r))
                {
                    // escape
                    InsertRecord(db, r);
                }
                else
                {
                    DeleteRecord(db, r);
                }
                tx.Commit();
            }
        }


        private bool ExistEscapeRecord(IDbManager db, AzRecord r)
        {
            var q = Query("core_acl", Tenant.DEFAULT_TENANT)
                .SelectCount()
                .Where("subject", r.SubjectId.ToString())
                .Where("action", r.ActionId.ToString())
                .Where("object", r.ObjectId ?? string.Empty)
                .Where("acetype", r.Reaction);
            return db.ExecuteScalar<int>(q) != 0;
        }

        private void DeleteRecord(IDbManager db, AzRecord r)
        {
            var q = Delete("core_acl", r.Tenant)
                .Where("subject", r.SubjectId.ToString())
                .Where("action", r.ActionId.ToString())
                .Where("object", r.ObjectId ?? string.Empty)
                .Where("acetype", r.Reaction);
            db.ExecuteNonQuery(q);
        }

        private void InsertRecord(IDbManager db, AzRecord r)
        {
            var q = Insert("core_acl", r.Tenant)
                .InColumnValue("subject", r.SubjectId.ToString())
                .InColumnValue("action", r.ActionId.ToString())
                .InColumnValue("object", r.ObjectId ?? string.Empty)
                .InColumnValue("acetype", r.Reaction);
            db.ExecuteNonQuery(q);
        }

        private AzRecord ToAzRecord(object[] r, int tenant)
        {
            return new AzRecord(
                new Guid((string)r[0]),
                new Guid((string)r[1]),
                (AceType)Convert.ToInt32(r[3]),
                string.Empty.Equals(r[2]) ? null : (string)r[2]) { Tenant = tenant };
        }
    }
}