/*
 *
 * (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.Data.Common;
using System.Configuration;
using ASC.Common.Data.Sql;
using ASC.Common.Data.Sql.Dialects;

namespace ASC.Common.Data
{
    public class DbProviderFactoryCustom
    {
        public string Name { get; set; }
        public string Invariant { get; set; }
        public string Description { get; set; }
        public string Type { get; set; }
    }

    public static class DbRegistry
    {
        private const string DEFAULT = "DEFAULT";
        private static readonly object syncRoot = new object();
        private static readonly IDictionary<string, DbProviderFactory> providers = new Dictionary<string, DbProviderFactory>(StringComparer.InvariantCultureIgnoreCase);
        private static readonly IDictionary<string, string> connnectionStrings = new Dictionary<string, string>(StringComparer.InvariantCultureIgnoreCase);
        private static readonly IDictionary<string, ISqlDialect> dialects = new Dictionary<string, ISqlDialect>(StringComparer.InvariantCultureIgnoreCase);
        private static volatile bool configured = false;

        static DbRegistry()
        {
            dialects["MySql.Data.MySqlClient.MySqlClientFactory"] = new MySQLDialect();
            dialects["System.Data.SQLite.SQLiteFactory"] = new SQLiteDialect();
        }

        internal static void RegisterDatabase(string databaseId, DbProviderFactory providerFactory, string connectionString)
        {
            if (string.IsNullOrEmpty(databaseId)) throw new ArgumentNullException("databaseId");
            if (providerFactory == null) throw new ArgumentNullException("providerFactory");

            if (!providers.ContainsKey(databaseId))
            {
                lock (syncRoot)
                {
                    if (!providers.ContainsKey(databaseId))
                    {
                        providers.Add(databaseId, providerFactory);
                        if (!string.IsNullOrEmpty(connectionString))
                        {
                            connnectionStrings.Add(databaseId, connectionString);
                        }
                    }
                }
            }
        }

        internal static void RegisterDatabase(string databaseId, string providerInvariantName, string connectionString)
        {
            RegisterDatabase(databaseId, DbProviderFactories.GetFactory(providerInvariantName), connectionString);
        }

        public static void RegisterDatabase(string databaseId, ConnectionStringSettings connectionString)
        {
            RegisterDatabase(databaseId, connectionString.ProviderName, connectionString.ConnectionString);
        }

        public static void UnRegisterDatabase(string databaseId)
        {
            if (string.IsNullOrEmpty(databaseId)) throw new ArgumentNullException("databaseId");

            if (providers.ContainsKey(databaseId))
            {
                lock (syncRoot)
                {
                    if (providers.ContainsKey(databaseId))
                    {
                        providers.Remove(databaseId);
                    }
                }
            }

            if (connnectionStrings.ContainsKey(databaseId))
            {
                lock (syncRoot)
                {
                    if (connnectionStrings.ContainsKey(databaseId))
                    {
                        connnectionStrings.Remove(databaseId);
                    }
                }
            }
        }

        public static bool IsDatabaseRegistered(string databaseId)
        {
            lock (syncRoot)
            {
                return providers.ContainsKey(databaseId);
            }
        }

        public static DbConnection CreateDbConnection(string databaseId)
        {
            Configure();

            if (!providers.ContainsKey(databaseId))
            {
                databaseId = DEFAULT;
            }

            var connection = providers[databaseId].CreateConnection();
            if (connnectionStrings.ContainsKey(databaseId))
            {
                connection.ConnectionString = connnectionStrings[databaseId];
            }
            return connection;
        }

        public static DbProviderFactory GetDbProviderFactory(string databaseId)
        {
            Configure();

            if (!providers.ContainsKey(databaseId))
            {
                databaseId = DEFAULT;
            }
            return providers.ContainsKey(databaseId) ? providers[databaseId] : null;
        }

        public static ConnectionStringSettings GetConnectionString(string databaseId)
        {
            Configure();

            if (!connnectionStrings.ContainsKey(databaseId))
            {
                databaseId = DEFAULT;
            }
            return connnectionStrings.ContainsKey(databaseId) ? new ConnectionStringSettings(databaseId, connnectionStrings[databaseId], providers[databaseId].GetType().Name) : null;
        }

        public static ISqlDialect GetSqlDialect(string databaseId)
        {
            var provider = GetDbProviderFactory(databaseId);
            if (provider != null && dialects.ContainsKey(provider.GetType().FullName))
            {
                return dialects[provider.GetType().FullName];
            }
            return SqlDialect.Default;
        }


        public static void Configure()
        {
            if (!configured)
            {
                lock (syncRoot)
                {
                    if (!configured)
                    {
                        foreach (var cs in Utils.ConfigurationManager.GetSettings<DbProviderFactoryCustom>("DbProviderFactories"))
                        {
                            DbProviderFactories.RegisterFactory(cs.Invariant, cs.Type);
                        }

                        var factories = DbProviderFactories.GetFactoryClasses();
                        AppDomain.CurrentDomain.SetData("DataDirectory", AppDomain.CurrentDomain.BaseDirectory); //SQLite

                        foreach (var cs in Utils.ConfigurationManager.ConnectionStrings)
                        {
                            var factory = factories.Rows.Find(cs.ProviderName);
                            if (factory == null)
                            {
                                throw new ConfigurationErrorsException("Db factory " + cs.ProviderName + " not found.");
                            }
                            RegisterDatabase(cs.Name, cs);
                        }
                        configured = true;
                    }
                }
            }
        }
    }
}