using Microsoft.Win32;
using MySql.Data.Entity;
using Step.Database.Controllers;
using Step.Database.Migrations;
using Step.Model.DatabaseModels;
using System;
using System.Data.Entity;
using System.Data.Entity.Migrations;
using System.IO;
using System.Linq;
using static Step.Config.ServerConfig;
using static Step.Model.Constants;
using static Step.Utils.ExceptionManager;

namespace Step.Database
{
    [DbConfigurationType(typeof(MySqlEFConfiguration))]
    public class DatabaseContext : DbContext
    {
        public DbSet<UserModel> Users { get; set; }
        public DbSet<MachineModel> Machines { get; set; }
        public DbSet<MachineUserModel> MachinesUsers { get; set; }
        public DbSet<RoleModel> Roles { get; set; }
        public DbSet<FunctionAccessModel> FunctionsAccess { get; set; }
        public DbSet<SessionModel> Sessions { get; set; }
        public DbSet<MaintenanceModel> Maintenances { get; set; }
        public DbSet<PerformedMaintenanceModel> PerformedMaintenances { get; set; }


        public static string CONNECTION_STRING = "Server = " + ServerStartupConfig.DatabaseAddress + "; Database=" + DATABASE_NAME +";Uid="+ DATABASE_USER +";Pwd="+ DATABASE_PWD +";";

        public DatabaseContext()
            : base(CONNECTION_STRING)
        {
        }

        public static DatabaseContext Create()
        {
            return new DatabaseContext();
        }

        public static void SetUpDbConnectionAndDbConfig()
        {
            try
            {
                System.Data.Entity.Database.SetInitializer<DatabaseContext>(null);

                // Make sure database exists.
                using (var db = new DatabaseContext())
                {
                    db.Database.Initialize(false);
                }

                var migrator = new DbMigrator(new Configuration());

                if (migrator.GetPendingMigrations().Any())
                {
                    // Run migrations and seed.
                    migrator.Update();
                }

                FindOrCreateMachineUniqueId();

                using (MaintenancesController maintenancesController = new MaintenancesController())
                {
                    maintenancesController.CheckDifferencesFromDbAndXml();
                }
                // Get functionality and PLC default false functionality
                using (FunctionsAccessController functionsAccess = new FunctionsAccessController())
                {
                    FunctionsAccessConfig = functionsAccess.FindAll();
                    AllFunctionalityDisabled = functionsAccess.FindAllFunctionsAndDisableAll();
                }
            }
            catch (MySql.Data.MySqlClient.MySqlException ex)
            {
                if (ex.Number == 0)
                {
                    //dbContext.Database.Initialize(true);
                }
                else if (ex.Number == 1042) // Can't find MySQLServer
                {
                    Manage(ERROR_LEVEL.FATAL, ex);
                }
                else
                {
                    Manage(ERROR_LEVEL.ERROR, ex);
                }
            }
            catch (Exception ex)
            {
                Manage(ERROR_LEVEL.FATAL, ex);
            }
        }

        public static void FindOrCreateMachineUniqueId()
        {
            // Find machine unique id in the register
            string uniqueId = ReadUniqueIdFromRegister();

            // If not found
            if (uniqueId == null || uniqueId == "")
            {
                if (!File.Exists("uniqueid.txt"))
                {
                    uniqueId = Guid.NewGuid().ToString();
                    // Save uinique id into file
                    File.WriteAllText("uniqueid.txt", uniqueId);
                    // Save uinique id in the registry
                    WriteUniqueIdIntoRegister(uniqueId);
                }
                else
                {
                    // Find machine unique id in the storage file
                    uniqueId = File.ReadAllText("uniqueid.txt");

                    // If null or empty
                    if (uniqueId == null || uniqueId == "")
                    {
                        // Delete empty file and recreate
                        File.Delete(uniqueId);
                        FindOrCreateMachineUniqueId();
                        return;
                    }
                    else
                    {
                        WriteUniqueIdIntoRegister(uniqueId);
                    }
                }
            }
            // Set machine info into static server config
            using (MachinesController machinesController = new MachinesController())
            {
                MachineConfig = machinesController.FindMachineByUniqueId(uniqueId);
                if (MachineConfig == null)
                {
                    // Create Machine inside database
                    MachineConfig = machinesController.Create(uniqueId);
                    using (UsersController usersController = new UsersController())
                    {
                        // Create default CMS user
                        usersController.CreateCmsDefaultUserIfNotExists(MachineConfig.MachineId);
                    }
                }
                else
                {
                    // if config name is different than dabase name, update db
                    if (MachineConfig.Model != NcConfig.NcName)
                        machinesController.UpdateMachineName(MachineConfig.MachineId, NcConfig.NcName);
                }
            }
        }

        private static void WriteUniqueIdIntoRegister(string uniqueId)
        {
            // Get path to the HKEY_LOCAL_MACHINE/SOFTWARE
            RegistryKey key = Registry.LocalMachine.OpenSubKey("SOFTWARE", true);
            // Create or get ..//CMS/Step subkey
            key = key.CreateSubKey("Cms").CreateSubKey("Step");
            // Set machine unique id Key
            key.SetValue(REGISTER_MACHINE_ID_KEY_NAME, uniqueId);
        }

        private static string ReadUniqueIdFromRegister()
        {
            // Get path to the HKEY_LOCAL_MACHINE/SOFTWARE
            RegistryKey key = Registry.LocalMachine.OpenSubKey("SOFTWARE", true);
            // Get ..//CMS/Step subkey
            key = key.CreateSubKey("Cms").CreateSubKey("Step");
            // Return value
            return (string)key.GetValue(REGISTER_MACHINE_ID_KEY_NAME);
        }
    }
}