using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace BankDAL
{
    public class BankAccountManager
    {

        public void TransfererArgent(string ibanOrigine, string ibanDestination, int montantATransferer)
        {
            using (SqlConnection connection = GetDatabaseConnection())
            {
                connection.Open();

                SqlCommand command = connection.CreateCommand();
                SqlTransaction transaction;

                // Start a local transaction.
                transaction = connection.BeginTransaction("SampleTransaction");

                // Must assign both transaction object and connection
                // to Command object for a pending local transaction
                command.Connection = connection;
                command.Transaction = transaction;

                try
                {
                    DebiterDe(montantATransferer, ibanOrigine, connection, command);
                    CrediterDe(montantATransferer, ibanDestination, connection, command);

                    transaction.Commit();
                }
                catch (Exception e)
                {
                    transaction.Rollback();
                    throw e;
                }
                finally
                {
                    connection.Close();
                }

            }
        }

        private void CrediterDe(int montantAAjouter, string iban, SqlConnection cn, SqlCommand mainCommand)
        {
            mainCommand.CommandText = "UPDATE [CompteEnBanque] SET [Solde]=[Solde]+@montantAAjouter WHERE [IBAN]=@ibanOrigine";
            mainCommand.Parameters.AddWithValue("@montantAAjouter", montantAAjouter);
            mainCommand.Parameters.AddWithValue("@ibanOrigine", iban);
            ExecuterRequeteEtVerifierImpact(mainCommand);
        }

        private void DebiterDe(int montantARetirer, string iban, SqlConnection cn, SqlCommand mainCommand)
        {
            mainCommand.CommandText = "UPDATE [CompteEnBanque] SET [Solde]=[Solde]-@montantARetirer WHERE [IBAN]=@ibanDestination";
            mainCommand.Parameters.AddWithValue("@montantARetirer", montantARetirer);
            mainCommand.Parameters.AddWithValue("@ibanDestination", iban);
            ExecuterRequeteEtVerifierImpact(mainCommand);
        }

        private static void ExecuterRequeteEtVerifierImpact(SqlCommand command)
        {
            var nombreDeComptesEnBanqueAffectes = command.ExecuteNonQuery();
            if (nombreDeComptesEnBanqueAffectes != 1)
                throw new BankAccountNotFoundException();
        }

        public static SqlConnection GetDatabaseConnection()
        {
            return new SqlConnection(ConfigurationManager.ConnectionStrings["MyVeryPrimitiveBank"].ConnectionString);
        }

        public double ObtenirSolde(string iban)
        {
            using (SqlConnection connection = GetDatabaseConnection())
            {
                connection.Open();
                var command = new SqlCommand("SELECT [Solde] FROM [CompteEnBanque] WHERE [IBAN]=@iban", connection);
                command.Parameters.AddWithValue("@iban", iban);
                var solde = (decimal)command.ExecuteScalar();
                connection.Close();
                return Convert.ToDouble(solde);
            }
        }
    }
}