/*
 *
 * (c) Copyright Ascensio System Limited 2010-2020
 *
 * 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.
 *
*/

namespace ASC.Data.Backup.Tasks
{
    public class ColumnMapper
    {
        private readonly Dictionary<string, object> _mappings = new Dictionary<string, object>();
        private readonly Dictionary<string, object> _newMappings = new Dictionary<string, object>();
        private readonly DateTime _now = DateTime.UtcNow;

        public int GetTenantMapping()
        {
            var mapping = GetMapping("tenants_tenants", "id");

            return mapping != null ? Convert.ToInt32(mapping) : -1;
        }

        public string GetUserMapping(string oldValue)
        {
            var mapping = GetMapping("core_user", "id", oldValue);

            return mapping != null ? Convert.ToString(mapping) : null;
        }

        public void SetDateMapping(string tableName, KeyValuePair<string, bool> column, object oldValue)
        {
            if (!column.Value)
            {
                SetMapping(tableName, column.Key, oldValue, _now);

                return;
            }

            var newValue = Convert.ToDateTime(oldValue);
            var tenantCreationDate = GetTenantCreationDate();
            if (tenantCreationDate != DateTime.MinValue && newValue > DateTime.MinValue.AddDays(1) && newValue < DateTime.MaxValue.AddDays(-1))
            {
                newValue = newValue.AddDays(_now.Subtract(tenantCreationDate).Days);
            }

            SetMapping(tableName, column.Key, oldValue, newValue);
        }

        public void SetMapping(string tableName, string columnName, object oldValue, object newValue)
        {
            if (tableName == "tenants_tenants")
            {
                var mapping = new MappingWithCondition { NewValue = newValue, OldValue = oldValue };
                AddMappingInternal(GetMappingKey(tableName, columnName), mapping);

            }

            AddMappingInternal(GetMappingKey(tableName, columnName, oldValue), newValue);
        }

        public object GetMapping(string tableName, string columnName)
        {
            var mappingKey = GetMappingKey(tableName, columnName);

            return HasMapping(mappingKey) ? ((MappingWithCondition)GetMappingInternal(mappingKey)).NewValue : null;
        }

        public object GetMapping(string tableName, string columnName, object oldValue)
        {
            var mappingKey = GetMappingKey(tableName, columnName, oldValue);
            if (HasMapping(mappingKey))
            {
                return GetMappingInternal(mappingKey);
            }

            mappingKey = GetMappingKey(tableName, columnName);
            if (HasMapping(mappingKey))
            {
                var mapping = (MappingWithCondition)GetMappingInternal(mappingKey);

                return mapping.NewValue;
            }

            return null;
        }

        public void Commit()
        {
            foreach (var mapping in _newMappings)
            {
                _mappings[mapping.Key] = mapping.Value;
            }

            _newMappings.Clear();
        }

        public void Rollback()
        {
            _newMappings.Clear();
        }

        private DateTime GetTenantCreationDate()
        {
            var mappingKey = GetMappingKey("tenants_tenants", "creationdatetime");
            if (HasMapping(mappingKey))
            {
                var mapping = (MappingWithCondition)GetMappingInternal(mappingKey);

                return mapping != null ? Convert.ToDateTime(mapping.OldValue) : DateTime.MinValue;
            }
            return DateTime.MinValue;
        }

        private void AddMappingInternal(string key, object value)
        {
            _newMappings[key] = value;
        }

        private object GetMappingInternal(string key)
        {
            return _newMappings.ContainsKey(key) ? _newMappings[key] : _mappings[key];
        }

        private bool HasMapping(string key)
        {
            return _newMappings.ContainsKey(key) || _mappings.ContainsKey(key);
        }

        private static string GetMappingKey(string tableName, string columnName)
        {
            return string.Format("t:{0};c:{1}", tableName, columnName).ToLowerInvariant();
        }

        private static string GetMappingKey(string tableName, string columnName, object oldValue)
        {
            return string.Format("{0};v:{1}", GetMappingKey(tableName, columnName), oldValue).ToLowerInvariant();
        }

        private class MappingWithCondition
        {
            public object NewValue { get; set; }
            public object OldValue { get; set; }
        }
    }
}