///
/// Copyright (c) 2021-2023 Sensus Slovensko a.s.
///
using System;
using System.Windows.Forms;
using NHibernate;
using NHibernate.Cfg;
using NHibernate.Tool.hbm2ddl;
using FluentNHibernate.Cfg;
using FluentNHibernate.Cfg.Db;
using Common;
using Events;
using TBF.Resources;
using System.Collections.Generic;

namespace TBF
{
    public class DB
    {
        ///
        /// Database related: This object reference is set after a successful user login
        ///
        public static DatabaseSettings CurrentBench;

        public static ISessionFactory ConfigDBSessionFactory = null;        /// Configuration DB session factory (always != null)
        public static ISessionFactory SharedDBSessionFactory = null;        /// Shared configuration DB session factory or null
        public static ISessionFactory ResultsDBSessionFactory = null;       /// Results DB session factory (always != null)
        public static ISessionFactory EventsDBSessionFactory = null;        /// Events DB session factory or null

        public static ISessionFactory LocalUsersDBSessionFactory = null;    /// Local users DB session factory (always != null)
        public static ISessionFactory SharedUsersDBSessionFactory = null;   /// Shared users DB session factory or null

        public static ISessionFactory[] UserSessionFactories
        {
            get
            {
                return (SharedUsersDBSessionFactory != null)
                    ? new ISessionFactory[] { SharedUsersDBSessionFactory, LocalUsersDBSessionFactory }
                    : new ISessionFactory[] { LocalUsersDBSessionFactory };
            }
        }

        /// <summary>
        /// Create all database session factories
        /// </summary>
        public static void CreateSessionFactories(DatabaseSettings dbSettings)
        {
            /// Configuration database (local, always non-null)
            if (dbSettings.ProceduresDBSettings != null && dbSettings.ProceduresDBSettings.IsValid)
            {
                ConfigDBSessionFactory =
                    CreateSessionFactory(m => m.FluentMappings.AddFromAssemblyOf<Config.Entities.Procedure>(),
                                         dbSettings.ProceduresDBSettings.DbType,
                                         dbSettings.ProceduresDBSettings.ConnectionString);

                LocalUsersDBSessionFactory =
                    CreateSessionFactory(m => m.FluentMappings.AddFromAssemblyOf<Users.Entities.User>(),
                                         dbSettings.ProceduresDBSettings.DbType,
                                         dbSettings.ProceduresDBSettings.ConnectionString);
            }

            /// Shared configuration database (remote)
            if (dbSettings.UsersDBSettings != null && dbSettings.UsersDBSettings.IsValid)
            {
                SharedDBSessionFactory =
                    CreateSessionFactory(m => m.FluentMappings.AddFromAssemblyOf<Config.Entities.Procedure>(),
                                         dbSettings.UsersDBSettings.DbType,
                                         dbSettings.UsersDBSettings.ConnectionString);

                SharedUsersDBSessionFactory =
                    CreateSessionFactory(m => m.FluentMappings.AddFromAssemblyOf<Users.Entities.User>(),
                                         dbSettings.UsersDBSettings.DbType,
                                         dbSettings.UsersDBSettings.ConnectionString);
            }

            /// Results database (local, always non-null)
            if (dbSettings.WaterMetersDBSettings != null && dbSettings.WaterMetersDBSettings.IsValid)
            {
                Results.DB.SessionFactory = ResultsDBSessionFactory =
                    CreateSessionFactory(m => m.FluentMappings.AddFromAssemblyOf<Results.Entities.Batch>(),
                                         dbSettings.WaterMetersDBSettings.DbType,
                                         dbSettings.WaterMetersDBSettings.ConnectionString);
            }

            /// Events database (remote or local)
            if (dbSettings.EventsDBSettings != null && dbSettings.EventsDBSettings.IsValid)
            {
                EventsDBSessionFactory =
                    CreateSessionFactory(m => m.FluentMappings.AddFromAssemblyOf<Events.Entities.Event>(),
                                         dbSettings.EventsDBSettings.DbType,
                                         dbSettings.EventsDBSettings.ConnectionString);
            }
        }

        /// <summary>
        /// NHibernate session factory (to create the database session 'SessionFactory')
        /// </summary>
        /// <returns>A database session</returns>
        public static ISessionFactory CreateSessionFactory(Action<MappingConfiguration> mappings, DBType dbType,
                                                           string connectionString, bool createDB = false)
        {
            try
            {
                var buildSchema = createDB ? (Action<Configuration>)BuildSchemaCreate : (Action<Configuration>)BuildSchema;

                switch (dbType)
                {
                    default:
                    case DBType.MySql:

                        return Fluently.Configure()
                                       .Database(MySQLConfiguration.Standard.ConnectionString(connectionString))
                                       .Mappings(mappings)
                                       .ExposeConfiguration(buildSchema)
                                       .BuildConfiguration()
                                       .SetProperty("hibernate.connection.connect_timeout", Const.MySqlConnectTimeoutSec)
                                       .BuildSessionFactory();

                    case DBType.SQLite:

                        return Fluently.Configure()
                                       .Database(SQLiteConfiguration.Standard.UsingFile(connectionString))
                                       .Mappings(mappings)
                                       .ExposeConfiguration(buildSchema)
                                       .BuildSessionFactory();

                }
            }
            catch (Exception exc)
            {
                MessageBox.Show(string.Format("{0}: {1}", Strings.Cannot_connect_to_the_database, exc.Message),
                                Strings.Error, MessageBoxButtons.OK, MessageBoxIcon.Error);
                return null;
            }
        }

        static void BuildSchema(Configuration config)
        {
            /// This NHibernate tool takes a configuration (with mapping info in)
            /// and exports a database schema from it
            new SchemaExport(config).SetOutputFile("db_schema");
        }

        static void BuildSchemaCreate(Configuration config)
        {
            /// This NHibernate tool takes a configuration (with mapping info in)
            /// and exports a database schema from it
            new SchemaExport(config).Create(true, true);
        }

        /// <summary>
        /// Create an empty users database.
        /// Database contains only the user 'admin' and the control board component 'CB'.
        /// </summary>
        /// <param name="dbType">DBType.SQLite or DBType.MySql</param>
        /// <param name="connectionString">Connection string</param>
        /// <returns>true=success, false=error</returns>
        public static bool CreateEmptyConfigDB(Common.DBType dbType, string connectionString)
        {
            ISessionFactory sessionFactory =
                CreateSessionFactory(m => m.FluentMappings.AddFromAssemblyOf<Config.Entities.Procedure>(),
                                     dbType, connectionString, true);

            if (sessionFactory == null) return false;

            /// Populate the database
            using (var session = sessionFactory.OpenSession())
            {
                using (var transaction = session.BeginTransaction())
                {
                    ///
                    /// Create user 'admin'
                    ///
                    var admin = new Config.Entities.User
                    {
                        UserName = Config.Data.AdminUsername,
                        FullName = Strings.Administrator,
                        LastPwChange = DateTime.Now
                    };
                    admin.SetPassword(Config.Data.AdminPassword);

                    ///
                    /// Prepare all groups, add some of them to admin
                    ///
                    for (Common.GID gid = 0; gid < Common.GID.NrOfGroups; gid++)
                    {
                        Config.Entities.Group group = new Config.Entities.Group(gid);
                        switch (gid)
                        {
                            case Common.GID.Testers:
                            case Common.GID.TestingSpecialists:
                            case Common.GID.HeadOfLab:
                            case Common.GID.MaintenanceSpecialists:
                            case Common.GID.Metrologists:
                            case Common.GID.CalibrationSpecialists:
                            case Common.GID.Administrators:
#if TURA_IPERL || TURA_IPERL_NEW || TURA_SPECIAL
                            case Common.GID.TraceabilityManagement:
#elif KEMPNO_50 || KRAKOW_50 || TORUN_50 || WARSAW_50 || WARSAW_END
                            case Common.GID.MetrologicalAuthority:
                            case Common.GID.WaterMeterAuthority:
#endif
                                admin.AddGroup(group);
                                session.SaveOrUpdate(group);    /// Save this group
                                break;
                        }
                    }

                    session.SaveOrUpdate(admin);                /// Save user 'admin'
                    transaction.Commit();
                }
            }

            return true;
        }
    }
}